FIELD OF THE INVENTION The invention relates to the field of making material, in particular granular or particulate material, collide, in particular with the object of breaking the grains or particles. However, the method of the invention is also suitable for other purposes for which materials have to be hit by grains or particles at great speed, such as treating, for example cubing or cleaning, grains and particles and treating and even deforming in a targeted manner, by means of impact loading, an object along its surface. A particular application is that of testing material or an object for hardness, wear-resistance and performance under impact loading.

Furthermore, the method of the invention may be used to generate a fast stream of material.

In addition to granular material, it is also possible to employ a liquid in the process, for example in the form of drops of liquid or a stream of liquid.

BACKGROUND OF THE INVENTION According to a known technique, material can be broken by subjecting it to an impulse loading. An impulse loading of this kind is created by allowing the material to collide with a wall at high speed. It is also possible, in accordance with another option, to allow partic- les of the material to collide with each other. The impulse loading results in microcracks, which are formed at the location of irregularities in the material. These microcracks continuously spread further under the influence of the impulse loading until, when the impulse loading is sufficiently great or is repeated sufficiently often and quickly, ultimately the material breaks completely and disintegrates into smaller parts. Depending on the specific material properties of the collision partners, in particular the mechanical properties, such as the elasticity, the brittleness and the toughness, and the strength, in particular the tensile strength, on the one hand of the material which collides with an impact face of an impact member at great speed and on the other hand of the material which forms the said impact face, these materials become deformed or yield during the impact. In any case, the impact loading always results in deformation and wear to both collision partners. The impact face can be formed by a hard metal face or wall, but also by grains or a bed of its own material.

The latter case is an autogenous process, and the wear during the impact remains limited.

The movement of the material is frequently generated under the influence of centrifugal forces. In this process, the material is flung away from a quickly rotating rotor, in order then to collide at high speed with an armoured ring which is positioned around the rotor and optionally rotates about a vertical shaft in the same or the opposite direction. If the aim is to break the material, it is a precondition that the armoured ring be composed of harder material than the impacting material ; or is at least as hard as the impacting material. The impulse forces generated in the process are directly related to the velocity at which the material leaves the rotor and strikes against the armoured ring. In other words, the more quickly the rotor rotates in a specific arrangement, the better the breaking result will be.

Furthermore, the angle at which the material strikes the armoured ring has an effect on the breaking probability. The same applies to the number of impacts which the material undergoes or has to deal with and how quickly in succession these impacts take place. This method is known from various patents and is employed in a large number of devices for breaking granular material or making it collide.

Since about 1850, many hundreds of patents have been granted worldwide for this method. A distinction can be drawn here between single impact crushers, in which the material is loaded by a single impact, indirect multiple impact crushers, in which the material is accelerated again after the first impact and loaded by a second impact, which process can be repeated further, and direct multiple impact crushers, in which the material is loaded in immediate succession by two or more impacts. Direct multiple impact is preferred, since this considerably increases the breaking probability.

A single impact crusher, intended for breaking granular material, was announced in the literature as early as 1870 (Ritter von Rittinger, Lehrbuche der Aufbereitungskunde, Figure 34), the crusher being equipped with a rotor on which are located relatively long guides, by means of which the material is accelerated and then flung outwards, at great speed, from the delivery end of the guides against a knurled, stationary armoured ring, which is disposed around the rotor, during which impact the material, if the velocity is sufficiently great, breaks. In the known device for breaking material by means of a single impact, the material to be broken is flung outwards, under the effect of the centrifugal forces, on rotation of the rotor. The velocity obtained by the material in the process is generated by guiding the material outwards along a guide, and is composed of a radial velocity component and a velocity component which is directed perpendicular to the radial component, in other words a transverse velocity component.

The theory of the single impact crusher was described extensively as early as 1889 (M. E. Bordier : Broyeur Vapalt ; Revue de L'Exposition de 1889, septième partie, Tome II,

Les machines-outils. Travail des divers Matériaux. Broyeurs, concasseurs, pulvérisateurs, etc., p. 627-631, 1889). When viewed from a stationary position, the take-off angle of the material to be broken from the edge of the rotor blade is determined by the magnitudes of the radial and transverse velocity components which the material possesses at the moment when it comes off the delivery end of the guide. If the radial and transverse velocity components are equal, the take-off angle is 45°. Since in the known single impact crushers the transverse velocity component is generally greater than the radial velocity component, the take-off angle is normally less than this, and lies between 35° and 45°. Over the relatively short distance covered by the material to be broken in the known devices until it strikes the impact face, the force of gravity, the air resistance, any air movements and a self-rotating movement of the grains normally have no significant effect on the direction of movement for (mineral) grains with diameters of greater than 5 mm. For grains with a smaller diame- ter, or grains composed of lighter material, the effect of the air resistance, in particular, increases considerably. As a general rule, it can be stated that the effect of the air resistance increases for grains of smaller diameter, while the effect of the grain configuration on the air resistance increases for grains of larger diameter. The known atmospheric impact crushers can be used to process material to a diameter of 1 to 3 mm. For smaller diameters, the breaking process has to take place in a chamber in which a partial vacuum can be created.

As long as the diameter is not too small, the material to be broken therefore moves, when seen from a stationary viewpoint, at a virtually constant velocity along a virtually straight line towards the location of the impact on the stationary armoured ring. The im- pact angle of the granular material against this armoured ring is defined by the take-off angle of the granular material from the delivery end of the guide and by the angle at which the impact face is disposed at the location of the impact.

In the known single impact crusher, the impact faces are generally disposed in such a manner that the impact in the horizontal plane as far as possible takes place perpendicularly.

The specific arrangement of the impact faces which is required for this purpose means that the armoured ring as a whole has a type of knurled shape. A device of this kind is known from US 5, 248, 101. The stationary impact faces of the known devices for breaking material are frequently of straight design in the horizontal plane, but may also be curved, for example following an involute of circle. A device of this kind is known from US 2, 844, 331. This achieves the effect of the impacts all taking place at an impact angle which is as far as possible identical (perpendicular). US 3, 474, 974 has disclosed a device for single impact in which the stationary impact faces are directed obliquely downwards in the vertical plane, with the result that the material is guided downwards after impact. This results in the

impact angle being more optimum, while the impact of subsequent grains is affected to a lesser extent by fragments from previous impacts, which is known as interference.

The problem with the known single impact crusher described is that the comminution process takes place during one single impact which is directed as perpendicularly as possible.

Examinations have shown that a perpendicular impact is not optimum for comminuting most materials by means of impact loading and that a greater breaking probability can be achieved, depending on the specific type of material, with an impact angle of approximately 75°, or at least between 70° and 85°. Furthermore, the breaking probability can be increased considerably further if the material for breaking is subjected to an impact loading not just once, but rather a number of times in quick succession, and at any rate at least twice.

Furthermore, in the impact crusher described, the impact of the granular material is to some extent considerably disturbed by the projecting corners of the impact plates. This interference can be given as the length which is calculated by multiplying the diameter of the fragments of material for breaking by the number of projecting corners of the armoured ring, with respect to the total length or the periphery of the armoured ring. In the known single impact crushers, frequently more than half the grains are interfered with during impact. This interference increases considerably as the corners of the impact plates become rounded by wear ; with the result that even the beneficial effect of directing the impact faces obliquely forwards and making them curved is quickly cancelled out.

The single impact, the impact angle which is as far as possible perpendicular, and the disturbing influences resulting from interference and above all from the projecting corners are the cause of the fact that the breaking probability of the known device described for breaking material by a single impact is limited, while the quality of the broken product can exhibit considerable variations. To achieve a reasonable degree of comminution, it is frequently necessary to increase the impact velocity, which requires extra power and causes the wear to increase considerably, while an undesirably high content of extremely fine particles may result.

DE 1, 253, 562 has disclosed a device for breaking grains by means of a single impact in which use is made of two rotor blades situated one above the other, which are both provided with guides and both rotate in the same direction, at the same angular velocity and about the same axis of rotation. In this device, a first part of the material is accelerated onto the upper rotor blade and is flung outwards against a first armoured ring which is disposed around the upper rotor blade. The second part of the material is accelerated onto the second rotor blade, which is situated below the first rotor blade, and is flung against a second armoured ring, which is disposed around this rotor blade. The capacity is thus

doubled, as it were. DE 1, 814, 751 has disclosed a device in which more than two systems are placed above one another.

Various patents have disclosed methods for accelerating granular material onto a ro- tor, the attempt being to achieve the required velocity while consuming as little power as possible and above all to limit the wear as far as possible.

US 3, 955, 767 has disclosed a device by means of which the material is accelerated by guide members which are provided with relatively long rotating radial guide faces. This process has the advantage that these grains are able to make good contact with the guide face and are flung outwards from the delivery end of the guide member at approximately the same velocity and at approximately the same take-off angle. However, the wear to these relatively long guides is extremely high ; this is because this wear increases very progressively, to the third power of the radial distance, as the velocity increases.

In addition to radially directed guides, devices are also known in which the guides are not disposed radially, but rather are curved forwards or backwards, when seen in the direction of rotation, and may even be of double-curved design. UK 309, 854 has disclosed a device in which the guides are bent backwards and the curvature is integrated with the curvature of stationary impact faces. UK 1, 434, 420 has disclosed a device in which the guides are designed in the form of a so-called scoop. EP 0, 191, 696 has disclosed a device in which the guides are bent forwards, in such a manner that the material itself attaches to the guide face under the influence of centrifugal force, so that an autogenous guide face is formed.

US 1, 875, 817 has disclosed a device in which rotating hammers are disposed along the outside of the rotor blade, by means of which hammers the material is flung against stationary impact plates. Symmetrical arrangements are also known, such as from US 1, 499, 455 and EP 0, 562, 194, which make it possible to allow the device to function rotating both forwards and backwards. UK 2, 092, 916 has disclosed a device in which the guide is designed in the form of a tube. It has been found that changing the form of the longitudinal direction of the guide face in general has a relatively limited effect on the wear and the power consumption, because it is, after all, necessary to achieve a certain velocity, at which the material to be broken is flung away and strikes the stationary impact member.

US 4, 787, 564 has disclosed a guide member in which the guide face is perforated, so that the material is directed better and, at the same time, is guided outwards at various levels situated parallel and next to one another.

WO 96/32195, in the name of the applicant, has disclosed a rotor-blade design in which the guides with the central feed are disposed at various levels, while the discharge ends lie more towards the outside and at the same level. This means that the number of

guides on the rotor blade, and thus the capacity, can be doubled without the feed of the material to the central feed of the various guide members being impeded.

US 5, 184, 784 has disclosed a method for accelerating granular material, in which guide shoes, in the form of projections, are disposed on the edge of a rotor blade, relatively far away from the axis of rotation. Thus the granular material, which is metered onto the centre of the rotor and, from there, spreads outwards over the rotor blade without hindrance, is taken up at a relatively great velocity, accelerated and flung outwards. This type of rotor, which exhibits less wear than a rotor which is equipped with longer, radially directed guides, which extend from the central part to the edge of the rotor blade, is in practice in widespread use in single impact crushers. The rotor blade of the known method, having the projections, does, however, exhibit the drawback that the acceleration takes place in a very uncontrolled manner. Grains can be taken up at the corners on the inside or the outside of the projection or anywhere along the face, and from there can be loaded by means of an oblique or perpendicular impact and flung away ; however, and this frequently occurs, they can also be accelerated by being guided along (a section of) the face of the projection, while combinations, in particular of an oblique impact followed by the partial guidance, are also possible. In these known methods, the grains are consequently flung outwards at extremely changeable and divergent velocities in various directions, while the wear to the guides is still in relative terms extremely high, in particular owing to impact friction and above all guide friction. Owing to the uncontrolled acceleration, the impacts of the various grains against the stationary, knurled armoured ring take place at very different velocities and at various angles. To achieve a reasonable level of comminution, the rotational speed of the rotor has to be adapted to the grains which have the lowest breaking probability, which strike against the armoured ring at the most unfavourable angle and at the lowest velocity. The rotational speed therefore has to be relatively high. The broken product thus exhibits a considerable spread in grain size distribution, frequently with a high content of undesirable, very fine constituents, while the power consumption and also the wear are still relatively high. US 3, 174, 698 has disclosed a single impact crusher in which round bars are mounted instead of projections. The metering face is formed by a relatively steep cone, the intention being to allow the material to strike the round bars at a high velocity, so that the grains can break even during this impact, after which the fragments are flung outwards against the stationary armoured ring. The symmetrical arrangement of the bars makes it possible to allow the rotor blade to rotate in both directions.

It is important that the material should be metered as evenly as possible onto the metering face on the centre of the rotor. It is necessary to avoid metering the material at

excessive velocity or from an excessive height. EP 0, 740, 961 has disclosed a device in which a metering chamber is disposed above the inlet of the rotor, from which metering chamber the material is metered onto the central part of the rotor blade in a uniform manner.

Methods are also known in which the granular material is accelerated not in one step, as in the above-described discovered methods for single impact, but rather in two steps, by means of guidance.

US 3, 032, 169 has disclosed a device for accelerating granular material, by means of which the grain particles are guided from the central part of the rotor blade with a relatively short preliminary guidance to longer guides disposed directly radially on the outside ; the material is accelerated along these longer guides and then flung against a stationary, knurled armoured ring disposed around the rotor blade. The object of the invention is to guide the grains, with the aid of the short preliminary guides, in a more regular distribution to the longer guides, specifically in such a manner that the grains do not strike these longer guides, but rather are accelerated along them, as far as possible by means of guidance, in order then to be flung outwards from the delivery end.

US 3, 204, 882 has disclosed a device for accelerating granular material, by means of which the granular material is guided, by means of a preliminary guide disposed tangentially directly along the central part of the rotor blade, to the guide face of a guide shoe, which guide face is directed more or less at 90'outwards and is disposed at the end of the first tangential preliminary guide. This design aims to prevent the granular material from striking the guide surface of the shoe structure with an impact, instead of which it is to be accelerated along the guide surface in a regular manner and as far as possible in a sliding movement, in order then to be flung outwards, past the delivery end of the guides, against a knurled armoured ring. It is stated that this method considerably reduces the wear and that the granules are accelerated more regularly. However, the wear to the guide face of the guide shoe is still high. Impact plates are additionally arranged behind the shoe structure, by means of which impact plates material or grain fragments which rebound after impact against this stationary armoured ring are collected and loaded again. These impact plates can also be designed as impact hammers and at the same time serve as a protective structure for the rotor.

Instead of a metal guide face, the material on the rotor blade can also be accelerated along a bed of the same material, i. e. an autogenous guide face. For this purpose, the rotor blade has to be equipped with a structure in which this same material accumulates under the effect of centrifugal force and forms an autogenous guide bed, in which case the structure in question is a chamber vane structure.

US 1, 547, 385 has disclosed a single impact crusher in which the material becomes attached to the rotor blade along sections of a circular wall, the material being accelerated and then flung outwards, primarily in a tangential direction, through openings in the cylinder wall, primarily with the tip velocity at that location. The amount of material which is guided outwards through the slot-like openings in the cylinder wall, that is to say the flow rate, is determined primarily by the radial velocity component which the material has at the moment at which it passes through the slot-like opening. On the baseplate of the cylindrical chamber, where the contact with the grains is limited, the material only develops a low radial velocity, with the result that the flow rate also remains limited ; moreover, it is only affected to a limited extent by the angular velocity. A further problem with the known structure is that the material becomes attached to the cylindrical wall section between the slot-like openings, so that bridges can easily be formed, so that the flow of the granular material outwards is considerably impeded. The manner in which the grains are guided outwards through the openings in the cylinder wall is extremely chaotic, because essentially there is an absence of any form of guidance. Another problem is presented by the considerable wear which occurs along the walls of the slot-like opening. US 1, 405, 151 has disclosed a similar design, in which the openings (delivery end) in the cylinder walls are provided with guide projections, so that an autogenous guide face can be formed. This design is improved further in US 4, 834, 298, so that a tangentially directed, autogenous guide face can be formed in the cylinder.

WO 96/20789 has disclosed a device in which the material on the centre of the rotor blade is taken up in a sleeve, from where it is flung outwards along the top edge, under the influence of centrifugal force. It is claimed that this considerably limits the wear.

US 3, 834, 631 has disclosed a design in which the cylinder is arranged in tumbling fashion.

JP 61-216744 has disclosed a symmetrical rotor-blade structure which has the form of a cone which widens downwards. The material is introduced from above onto a co-rotating distributor disc which is suspended in the top of the cone and, from there, is flung outwards, where the material becomes"attached"to the inside of the cone in vane structures which are arranged there. In these structures there is formed an autogenous guide bed which is, as it were, inverted and along which the material is accelerated and flung outwards along the bottom of the edge of the cone.

US 3, 174, 697 has disclosed a device for accelerating granular material, in which the rotor is equipped with a guide, each in the form of two chamber vanes which are positioned in line with one another. Under the influence of centrifugal force, the granular material accumulates in these chamber vanes, resulting in the formation of a type of bent, tangentially

directed, autogenous guide face, along which the granular material is accelerated and flung outwards.

US 3, 162, 386 has disclosed a similar device for accelerating granular material with guide arms which are directed radially outwards and along which guides more than one vane structure is fastened, each of which is disposed tangentially in such a manner that the granular material accumulates in these vanes under the influence of centrifugal force, with the result that the vanes as a whole form an autogenous bed of grains, along which the granular material is accelerated and flung outwards by stepwise guidance. This combination aims to prevent the material from rubbing too much against the rotor blades, due to the fact that the fillet-like top ends of the fillings in the chamber vanes as a whole form an autogenous guide face, along which the material is accelerated and guided outwards. The number of chamber vanes is determined by the diameter of the rotor. At the same time, the wear to the guides, and in particular to the rotor, is limited. This is because the vanes are designed in such a manner that the granular material is prevented from rubbing along the bottom plates and top plates of the rotor housing, as a result of which wear to these plates is prevented. In a supplementary US Patent 3, 346, 203, a protective structure is also provided for the device of this invention, which structure is arranged in the form of pins along the edge of the rotor, between the upper and lower blades, thus preventing granular material which rebounds after it has struck the stationary armoured ring from damaging the rotor-blade structure.

The known crusher brings about a certain degree of direct, multiple autogenous impact, albeit uncontrolled. Since the"impact face"essentially functions as the subsequent guide face, this action is ineffective.

EP 0, 101, 277 has disclosed a method for accelerating granular material and making it collide, using guides which are disposed virtually tangentially and, furthermore, are designed such that an autogenous guide face made of the same material is formed against these guides, under the influence of centrifugal force. The known structures, by means of which an autogenous guide face is formed, aim to limit wear. However, a relatively great amount of wear occurs at the delivery end of a guide of this kind. Moreover, the tangential arrangement of the guide is the cause of the fact that the radial velocity component is used only to a very limited extent for accelerating the material. The grains come off the delivery end with essentially only the tip velocity and scarcely any radial velocity. As a result, much of the added energy, approximately half, is lost. Furthermore, a large quantity of energy is lost because the grains in the rotor are guided towards the edge of the rotor in an essentially unnatural, forwards movement. Consequently, the known rotor structure has only a limited efficiency. A major problem with the known crushers is that because the grains do not

develop any radial velocity along the guides, they do not have any outwards velocity, when seen from the viewpoint which moves together with the delivery end, when they come off the delivery end of the guide, and therefore they move directly backwards, seen in the direction of rotation, and cause intense wear along the outer edge of the delivery end (tip).

Thus, moreover, considerable velocity is lost. Dozens of tip designs are known for the delivery end of rotors of this kind, which designs aim to limit the wear, and are known inter alia from US 5, 131, 601 and EP 0, 187, 252, EP 0, 265, 580 and EP 0, 452, 590, UK 2, 214, 107 and WO 95/10358, WO 95/10359 and WO 95/11086. However, none of the known tip designs functions satisfactorily, and they are unable to prevent the occurrence of intense wear at the delivery end. US 4, 390, 136 has disclosed a device in which the guide, which is of symmetrical design, is formed by vertical bars, which are disposed along the edge of the rotor blade in such a manner that a type of semi-autogenous guide face is produced.

The material is flung from the rotor against an armoured ring disposed around the rotor, during which impact the material breaks. It is possible to combine the guide and impact structures in various ways : a steel guide face and a steel impact face, known as steel-on-steel, an autogenous guide face and a steel impact face, known as stone-on-steel, an autogenous guide face with an autogenous impact face, known as stone-on-stone, and a steel guide face with an autogenous impact face, known as steel-on-stone.

The armoured ring is generally formed by separate elements, i. e. impact plates, which are disposed around the rotor blade with their impact face directed perpendicular to the straight path which the grains describe when they are flung outwards from the rotor blade.

The wear to the impact plates is relatively high, since the grains continuously rub along them at high speed. US 4, 090, 673 has disclosed a typical structure (steel-on-steel) in which the separate impact plates are provided with a special fastening structure, so that they can be exchanged quickly. JP 2-237653 has disclosed a device in which the impact faces are designed such that less hindrance is undergone as a result of the wear of the projecting corners. EP 0, 135, 287 has disclosed a design in which the impact plates comprise elongate, radial blocks which are disposed next to one another around the rotor blade. These blocks, as they become worn, can always be moved forwards, so that they have a longer service life. In this case, the impact face of the armoured ring is knurled centrally and is no longer directed perpendicular to the path which the grains describe. Overall, it has to be stated that in the known crushers the wear is relatively high in relation to the intensity of comminution.

JP 06000402 and JP 06063432 have disclosed devices in which the impact plates are

vertically adjustable, so that the wear can be spread more evenly along the impact face.

JP 06091185 has disclosed a device which is symmetrical and in which it is possible to change the length of the guide members in the radial direction and to adjust the height of the impact faces. This document contains an extensive (theoretical) discussion of the movement of granular material along a radially disposed guide face.

Instead of an armoured ring, against which the material is flung from the delivery end of the autogenous guide, a trough structure may be disposed around the edge of the rotor, in which trough an autogenous bed of the same material builds up, against which bed the granular material which is flung off the rotor blade then strikes (stone-on-stone).

US 4, 575, 014 has disclosed a device with an autogenous rotor blade, from which the material is flung against an armoured ring (stone-on-steel) or a bed of the same material (stone-on- stone). JP 59-66360 has disclosed a device in which the material is flung from steel guides onto an the same bed (steel-on-stone). Comminution takes place in the bed of the same material by the grains colliding with one another and undergoing friction. As a result, the wear is limited further ; however, the impact intensity, i. e. the impulse loading of the grains in the autogenous ring, is limited in the known method. Due to the fact that primarily the transverse velocity component (tip velocity) is active and the radial velocity component, although limited, is variably active, the grains are guided into the autogenous bed at extremely shallow but very diverse angles (from approximately 5° to 20°). Consequently, the impact against the autogenous bed of the same material takes place at a very oblique, and moreover variable impact angle, which as a result has limited effect. As a result, the grains are guided in a movement"running round"along the autogenous bed. When the grains collide with one another, the impacting grains are loaded against grains which con- tinue to move along the said bed of the same material ; i. e., as it were, from behind, which also has little effect. The level of comminution of the known method is therefore low, and the crusher is primarily employed for the after-treatment of granular material by means of rubbing the grains together, and in particular for"cubing"irregularly shaped grains. A further drawback is that if the material for breaking contains fine material, or a large number of small particles are formed during the autogenous treatment, the autogenous bed can easily become blocked, forming a so-called dead bed of fine particles. Material which strikes against and rubs along a dead bed of this kind is relatively ineffective. It is therefore in actual fact not possible to call this a comminution process, but rather a more or less intensive after-treatment process for material which has already been broken.

JP 04300655 has disclosed a single impact crusher in which the autogenous ring is designed so that it can be emptied at the bottom, thus allowing the bed of the same material

to be, as it were, exchanged regularly. As a result, a dead bed is less likely to form. US 4, 844, 364 has disclosed a single impact crusher in which the autogenous bed is formed in a structure in which it can move right round, thus aiming to make the autogenous action more intensive.

JP 07275727 has disclosed a single impact crusher in which an armoured ring is disposed around part of the rotor and a bed of the same material is disposed around part of the rotor, so that the intensity of comminution differs considerably and a grain size distribution with a large dispersion can be achieved.

EP 0, 074, 771 has disclosed a method for breaking material using autogenous guides and a stationary bed of the same material, in which part of the granular material is not accelerated but rather is guided around the outside of the rotor. Two streams of grains are thus formed, a horizontal first stream of grains, which is flung outwards onto the rotor from the guides, and a vertical second stream of grains which, as it were, forms a curtain of granular material around the guides. The material from the first accelerated horizontal stream of grains now collides with the material of the second, unaccelerated vertical stream of grains, whereupon the two collided streams of grains are taken up in an autogenous bed of the same material, so that this can be known as an inter-autogenous comminution process.

This method, which aims to save energy and to reduce the wear, has a number of drawbacks.

The loading takes place by the perpendicular collision between a grain moving quickly in the horizontal direction and a grain moving relatively slowly in the vertical direction. The effectiveness of a collision of this kind is essentially low ; in the most favourable scenario, when grains of the same mass hit each other full on, at most half of the kinetic energy is transmitted, while only a limited fraction of the grains actually contact each other fully.

Furthermore, the material which is accelerated with the guide is concentrated in separate first horizontal streams of grains, which are guided, from the guides, around the inside of a vertical curtain, or second stream of granular material. Consequently, the grains from the second stream of grains are not all loaded uniformly. In fact some of the grains from the second stream of grains are not even touched at all before being collected at the bottom in the bed of the same material. The specific, very oblique angle at which the grains from the first stream of grains leave the rotor blade is furthermore the reason for the intensity of the impact of the collided material from the first and second streams of grains against the autogenous bed of the same material being limited. The effectiveness of the known method is therefore limited. Here too, a dead autogenous bed is easily formed, as a result of which the autogenous action along the bed of the same material is limited. Moreover, the method is extremely susceptible to changes in the quantitative distribution of the material across

the first and second streams of grains.

US 3, 044, 720 has disclosed a device for indirect multiple impact, in which the material is flung, with the aid of a first rotor blade, against a first stationary armoured ring where, after impact, it is taken up and guided to a second rotor blade situated beneath the first, which rotates at the same angular velocity, in the same direction and about the same axis of rotation as the first rotor blade, on which second rotor blade the second part of the material is accelerated for the second time, frequently at greater velocities than during the impact against the first impact face, and flung against a second stationary armoured ring, which is disposed around this second rotor blade. US 3, 160, 354 has disclosed methods in which this process is repeated a number of times, or at least more than twice. US 1, 911, 193 has disclosed a device in which the impact plates on the rotor blade situated at a lower level are disposed ever further from the axis of rotation, so that the impact velocity increases.

DE 38 21 360 (JP 0596194) has disclosed a method for indirect multiple impact, in which the material, after it has been accelerated for the first time on a first rotor blade and flung against an armoured ring, is taken up on a second rotor blade, situated below the first, from where it is flung against an autogenous bed of the same material. JP 08192065 has disclosed a similar device, in which the material is flung from both the first and the second rotor blades against a bed of the same material. This structure aims, inter alia, to utilize as much as possible of the kinetic energy which the grain still possesses after the first impact. However, this kinetic energy is generally limited, since the material often loses virtually all its kinetic energy during the stationary impact and, as it were, kills this energy. In order to prevent the formation of a dead bed in the autogenous ring, air can be injected into the trough structure from below, so that relatively fine particles can be blown out of the material bed.

Indirect multiple impact of this kind can achieve a high level of comminution. However, the wear and the power consumption are high, while it is frequently difficult, after the first impact, to guide the material uniformly to the next rotor blade, on which the material is accelerated again and undergoes a second impact.

WO 94/29027, which is in the name of the applicant, has disclosed a device for direct multiple impact, the impacts taking place in an annular and slot-shaped space between two casings which are positioned one above the other and are in the form of truncated cones which widen downwards and which are both rotatable in the same direction and at the same angular velocity as the rotor, around the same axis of rotation. Instead of cones, in the known method for direct multiple impact, the impact faces can also be composed of straight faces which are disposed in the centre before the delivery end of the guides and, in the

horizontal plane, are directed perpendicular to the radius of the rotor. This angle which is directed perpendicularly in the horizontal plane may be altered by +10° and-10°, thus allowing the material which is to be broken to be guided downwards between the impact faces as far as possible perpendicularly in a zig-zag path of direct multiple impact, and making it possible to prevent the material to be broken from striking the side walls of the breaking chamber. In the rotating breaking chamber, primarily the radial velocity compo- nent is utilized ; the residual energy, which is mostly transverse, is only utilized after the material is guided out of the rotating breaking chamber and strikes stationarily disposed impact faces.

Instead of being stationary, the impact face may also be designed to rotate, about the same axis of rotation as the rotor blade. In this case, rotation can take place in the same direction and at the same angular velocity as these guides, but also oppositely thereto.

UK 376, 760 has disclosed a method for breaking granular material, by means of which a first and a second part of the granular material are flung outwards, with the aid of two guides which are situated directly above one another, are directed towards one another and rotate around the same axis of rotation but in opposite directions. As a result, the two streams of grains are oppositely directed, with the result that the grains hit each other at a relatively great velocity and are then taken up in a trough structure which is disposed around the two rotor blades and in which the granular material builds up a bed of the same material. In order to allow the grains to hit each other correctly, it is necessary to concentrate the oppositely directed streams of grains as far as possible in one plane between the rotor blades. With guides, this can be achieved only to a limited extent, because the grains, when they come off the delivery end, under the influence of centrifugal force, immediately move outwards in a horizontal path. Therefore, only a limited fraction of the grains actually collide fully with one another. The specific arrangement of the guides, which is necessary in order as far as possible to move the streams of grains into one plane when they come off the delivery end of the guides is the reason for the wear to the guides being relatively great.

JP 2-227147 has disclosed a similar structure in which the material is launched from a symmetrical autogenous structure.

JP 2014753 has disclosed a device in which the material on a rotor, which is equipped with autogenous guides, is flung outwards against an autogenous bed of the same material, which is formed in a trough structure which rotates in the same direction as the rotor, but is driven separately.

DE 31 16 159 has disclosed a device in which an autogenous ring is disposed around a sleeve structure in the centre of the rotor blade, which autogenous ring rotates in a direction

opposite to that of the sleeve structure.

JP 2-122841 has disclosed a device in which a rotor is disposed in the centre, which rotor is provided with first chamber vanes, in which material accumulates, forming a guide face, around which is disposed a rotor with similar, second chamber vanes which rotate in the opposite direction and from which the material is flung into the autogenous bed disposed around it. The material is flung from the first chamber vane at great velocity against the material in the second chamber vane and, from there, into the stationary autogenous ring.

A problem with the known crusher is the transfer from the first to the second chamber vane, which is impeded to a considerable extent by the edges of the chamber vanes.

JP 2-122842 has disclosed a device in which a ring structure is disposed around the outside of the rotor with chamber vanes, which rotor is disposed in the centre, which ring structure rotates in the opposite direction and an autogenous bed accumulates therein.

JP 2-122843 has disclosed a crusher, of which two rotors are disposed in the crusher chamber, which are provided with two rotors, which are positioned one above the other, rotate in opposite directions about the same shaft and are each provided with chamber vanes, the material being guided outwards into the autogenous ring in two oblique paths which are situated one above the other and in opposite directions, which process leads to an intense after-treatment. A disadvantage is that the jets do not immediately contact one another, but rather do so only after they have struck the autogenous bed.

A significant problem with the known rotors operating in opposite directions is the complicated separate drive.

SU 797761 has disclosed a device in which the material, after it has been accelerated on the rotor blade, is flung outwards against a stationary, knurled edge, from where it is taken up again by projections which are fastened along the edge of the rotor. However, this process, which is known as direct multiple impact, is disrupted by the material not rebounding"cleanly"when it strikes the points of the knurled edge and not being taken up by the projections.

DE 39 26 203 has disclosed a rotor structure in which rebound plates are disposed behind the chamber vanes for taking up material which rebounds from the armoured ring, i. e. direct multiple impact. JP 06079189 has disclosed a similar, but symmetrical design for indirect multiple impact, the rebound plates being fastened in a pivoting manner along the outer edge. US 2, 898, 053 has disclosed a direct multiple impact crusher in which the material, after it has struck a stationary armoured ring from the rotor blade, is taken up by impact plates which are suspended along the bottom of the rotor blade.

DE 39 05 365 has disclosed a direct multiple impact crusher, by means of which the

material is guided from the rotor blade between impact faces which are directed radially outwards, are positioned next to one another and are disposed around the rotor blade. The material executes a zig-zag movement between these impact plates. A problem with the known impact crusher is the disruption from the points of the impact plates.

EP 0 702 598, which is in the name of the applicant, has disclosed a direct multiple impact crusher, by means of which the material, after it is flung from the rotor blade, is taken up in a circular, gap-like space which is disposed around the rotor blade and in which the material is guided downwards in a zig-zag path. This crusher functions only if the distance between the edge of the rotor blade and the surrounding stationary impact face is made to be relatively great.

PCT/NL96/00154 and PCT/NL96/00153, which are in the name of the applicant, have disclosed a method for direct multiple impact, in which the impact face is formed by a planar armoured ring which is disposed around the rotor and can be rotated in the same direction and at the same angular velocity as the rotor, around the same axis of rotation ; furthermore, its impact face, which is directed inwards, has a conical shape which widens downwards. The material, which after the first impact still has a considerable residual velocity, is guided further to a stationary second impact plate or bed of the same material, where it undergoes the second impact. When seen from a co-rotating position, i. e. when seen from a viewpoint which moves together with the rotor, primarily the radial velocity component is active at the moment that the grain comes off the delivery end of the guide.

The transverse velocity component of the material to be broken is in fact at that moment equal to that of the delivery end. After the material to be broken comes off the delivery end, it bends off gradually, when seen from a viewpoint which moves together with the rotor, in a direction towards the rear, when seen from the direction of rotation, thus describing a spiral path. In the known method for direct multiple impact, the impact face is directed perpendicular to the radius of the rotor shaft and therefore has to be disposed at a relatively short radial distance from the delivery end of the guide, because, if this distance becomes too great, the angle at which the material to be broken strikes the horizontal face becomes too oblique, with the result that the impact intensity decreased considerably and the wear increases considerably. The short distance required is the cause of the impact velocity against the co-rotating impact face being defined primarily by the radial velocity compo- nent. In order to generate a reasonable radial velocity component, the guide on the rotor blade has to be made relatively long, or else the angular velocity has to be raised considerably, which in both cases leads to a high level of wear to the guide and extra power consumption.

Since the transverse component does not contribute to the impact intensity, or does so only

to a limited extent, a not insignificant part of the energy supplied to the material to be broken is not used profitably during this first impact. However, the unused energy to a large part remains after the first impact, and in the known method for multiple impact is utilized during one or more immediately following impacts against stationary impact faces.

SU 1, 248, 655 has disclosed a device in which an impact means is situated outside the rotor, in line with the guide, the centre of the radial impact face of which impact means is directed perpendicular to the radius which joins this centre to the centre of the rotor, which impact face can be rotated at the same velocity as the rotor around the axis of rotation. The impact face is in this case disposed at a relatively short radial distance beyond the delivery end of the guide, since, if the radial impact face were to be disposed at a greater distance beyond the guide, the material to be broken would pass along the back of the impact face, when seen in the direction of rotation. The relatively short distance between the delivery end and the impact face has the consequence that the transverse velocity component scarcely contributes to the impact intensity, as a result of which, since the residual energy in this known method is not utilized further in the first impact, a large proportion, approximately half, of the energy supplied to the material to be broken is completely lost.

FR 2, 005, 680 has disclosed a direct multiple impact crusher, in which the rotor is equipped with guides which in relative terms are very short and are disposed close to the axis of rotation. In this case, the material is not metered centrally onto the rotor blade, but rather directly above the guides, from where it is flung outwards, whereupon the material is taken up by a large number of short radial impact faces which are mounted along the edge of the rotor blade. A large number of short, radially directed, stationary impact faces are disposed directly around these guides, resulting in a sort of grinding track. The conveyance of the grains between these impact faces is given extra impetus with the aid of an air flow. A problem with the known device is that there is a considerable disturbing effect during the entry of the material at the location of the top edges of the short guides, with the result that the impact acceleration is extremely chaotic, and also that there is a considerable disturbing effect at the location of the points of the co-rotating impact faces.

JP 54-104570 (US 4, 373, 679) has disclosed a direct multiple impact crusher, in which the material is metered into a thin-walled cylinder which is located on the central part of the rotor blade, from where the material is flung outwards through slot-like openings in the cylinder wall, under the effect of centrifugal force. Impact members are fastened along the edge of the rotor at some distance outside the cylinder. These impact members are preferably formed by pivoting hammers. The cylinder structure with the slot-like opening is selected so as to minimize the length of the impact faces, so that the grains are not accelerated

radially, but rather, with an impact, are guided outwards from the cylinder in an essentially tangential path only under the effect of the transverse velocity component (tip velocity).

The aim of the method is to guide the material outwards always in an essentially tangential -i. e. essentially the same-direction, irrespective of the rotational speed of the rotor. It is stated that if the grains are guided outwards in a tangential path of this kind, the movement of the grains, even those with a relatively small diameter, is not affected by turbulence caused by the rotating hammers. Furthermore, the tangential path makes it possible to control the location where the grains strike the co-rotating hammers, by turning the cylinder with respect to the hammers. The known crusher has a number of drawbacks. The material which is metered onto the centre of the rotating rotor blade on the bottom of the cylinder describes, when seen from the slot-like opening in the cylinder wall, an outwardly directed spiral (Archimedes'spiral) path in a direction opposite to the direction of rotation of the rotor. In doing so, the material develops, with respect to the slot-like opening, only a low speed. It is therefore inevitable that part of the material will pass through the slot-like opening without coming into contact with the edge of the slot-like opening, i. e. will, as it were, roll outwards through the gaps. Some of the material comes into contact with the edge and in so doing is accelerated by means of an impact, in which case the material can be hit by the points or by the short impact face, or by the very short impact face. A signi- ficant problem with the crusher according to the invention is that since the material is unable to develop any radial velocity component, or can develop only a very limited radial velocity component, the flow rate of the said rotor blade, which is essentially a function of the radial velocity component, is limited. This was pointed out earlier in the discussion of cylindrical guide members of this kind. Furthermore, the feed of the material to the slot- like opening is disturbed to a considerable extent, due to the fact that, under the effect of centrifugal force, material becomes attached to the cylinder segments between the slot- like openings, with the result that bridges are formed in the cylindrical space. Only a limited amount of the grains will really hit the impact face of the hammers full on, with the impacts taking place spread along the impact face. Moreover, since there is no protective (tip) structure provided, the edge will become worn very quickly and irregularly, with the result that the way in which the grains are guided outwards is disturbed further. In order nevertheless to subject all the grains to an impact, a second set of hammers is provided which are mounted along the edge of the rotor blade, in a plane directly below the first hammers.

EP 0, 562, 163 has disclosed a symmetrical multiple impact crusher in which the rotor blade is equipped along the edge with hammers, the material being metered from above

these hammers and being guided with an impact between stationary impact plates which are directed radially outwards. After striking these plates, the material falls downwards, where it is taken up by a second set of hammers, which rotate along the inside of a steel armoured ring, the opening between the hammers and the armoured ring forming a gap, so that a maximum grain dimension of the broken product is limited.

US 4, 145, 009 has disclosed a rotor blade which is provided along the edge with hammers, the material being metered around the rotor blade, above the rotating hammers.

An armoured ring is disposed around the outside of the hammers, the distance between the hammers and the armoured ring being adjustable, so that the maximum grain dimension of the broken product can be controlled.

In principle, it is possible with direct multiple impact crushers to synchronize the movement of the impact members in such a manner that the grains are always hit full on by the respective impact faces.

US 1, 331, 969 has disclosed a multiple synchronized impact crusher in which the moving impact plates are mounted on two rotors which are situated next to one another and rotate about horizontal shafts, the rotating movement of the rotors being mutually adapted so that the material is successively hit firstly full on by the first impact plate and immediately afterwards full on by the second impact plate.

EP 0, 583, 515 has disclosed a device for direct multiple (double) impact, in which the material is comminuted by a first impact plate which rotates around a first axis of rotation and from which the material is guided in a direction towards a second impact face, which rotates about a second axis of rotation and the rotating movement of which is synchronized with that of the first impact face in such a manner that the material is hit full on twice immediately in succession. A problem with the known method is that the direction in which the material is guided from the first impact face inevitably exhibits a certain dispersal, with the result that this material is hit by the second rotor blade at"considerably"differing distances and thus at"considerably"differing tip velocities of the axis of rotation. It is claimed that impact against a stationary wall provides the lowest possible loading.

Impact loading is also used for the production of extremely fine material with diame- ters of less than 100 Rm and even 10 m. Since the movement of fine material is affected to a considerable extent by the air resistance, the rotor therefore has to be disposed in a chamber in which there is a vacuum. To break fine material (powder) by impact loading to give an extremely fine product, the material has to be introduced at a very great velocity, which places high demands on the structure whose rotor blade has to rotate at a very high speed, while a high level of wear is found on the means by which the material is accelerated.

US 4, 138, 067 has disclosed a single impact crusher in which the material is flung outwards with the aid of a rotor, which is provided with closed guide ducts, into a chamber in which there is a vacuum and in which a stationary armoured ring is disposed around the outside of the rotor.

US 4, 738, 403 has disclosed a vacuum crusher which is equipped with a rotor blade with guides which are curved forwards in such a manner that, under the influence of centrifugal force, material of the same type becomes attached to them, as such forming a guide face made of the same material. The rotor is furthermore equipped with a special tip structure, which guides the material outwards in a manner which as far as possible is autogenous.

US 4, 697, 743 has disclosed a direct multiple impact crusher with a rotor which is disposed in a crushing chamber in which a vacuum prevails. Arms, which at the ends are provided with impact plates, are attached to the rotor. The material is guided into the crushing chamber at a relatively high speed from above, at locations situated directly above the circular movement which these impact plates describe. This material is taken up by the rotating impact plate, where it is struck directly against a stationary armoured ring which is disposed in the stationary crushing chamber around the outside of the impact plate. A similar design is known from US 4, 645, 131.

For very fine comminution, it may be necessary to cool the material considerably, so that it becomes more fragile and breaks more easily on impact.

EP 0, 750, 944 has disclosed a device in which a rotor, which is cooled with the aid of a light gas, for example helium or hydrogen, is disposed in the crushing chamber, in which a vacuum, or at least subatmospheric pressure, prevails.

A problem with the known vacuum crushers is primarily the wear to the rotor blade with which the material has to be brought to extremely high speeds.

Collision can be used not only for crushing but also for sorting granular material for hardness, if the differing hardnesses of the separate grains are accompanied by a difference in elasticity, as is normally the case. Material with high elasticity rebounds at a greater velocity, and hence further, than material with a lower elasticity. The theory involved here is essentially sorting on the basis of the restitution behaviour of the grains. DE 872, 685 has disclosed methods which employ this principle for sorting material, the granular material being flung from the rotor blade against a stationary wall. EP 0, 455, 023 has disclosed an indirect multiple impact crusher, the material being flung from the rotor blade against a forwardly (downwardly) directed armoured ring. Material with a low coefficient of restitution and broken fragments fall downwards after the impact, while material with a

higher coefficient of restitution rebounds and is taken up on a second rotor blade which is disposed along the bottom edge of the first rotor blade, from where it is flung back against the armoured ring.

Besides breaking, sorting and accelerating granular material, various methods are known in which materials or objects are processed by means of impact loading. Examples of these are the treatment of granular material with the aim of cleaning this material, for example by removing, during the impact, a layer of a different type of material, for example clay, which has become attached to the surface of the grains (moulding sand). It is also possible to separate soft materials selectively from the granular material by selecting the impact velocity in such a manner that the soft constituents are pulverized and the hard constituents are not affected.

Conversely, an object may be treated using impact from granular material, optionally mixed with a liquid, or solely by the impact of a liquid. Known processes are sand-blasting and shot-peening. A design of this type is known from US 3, 716, 947.

It is also possible to treat a surface of an object, and even, with the aid of impact loading, to apply a layer of a different type of material ; it is even possible to use a method of this kind to prestress a material. With regard to the treatment, in addition to finishing a surface it is also possible to consider repairing weld seams and even repairing microcracks along the surface. Furthermore, an object can be shaped and deformed by means of impact loading. The article by W. Earl Hanley,"Shot blasting your way to better finishes", Ma- chine design, March 20, 1975, provides an overview of various methods for treating material using impact loading. Furthermore, impact loading can be used to test both a material and an object for hardness, wear and fracture behaviour. Various methods have been developed for this.

Impact loading forms a major problem in the design and selection of materials for building aircraft and turbine blades of steam turbines and centrifugal pumps. In space travel too, much attention is paid to the effect of impact loading on the surface of spacecraft.

Aircraft are exposed to impacts from drops of water, hail and dust particles. The same applies to the turbine blades of the motors. The blades of steam turbines are exposed to the impact of hot steam and drops which have condensed out of this steam. Pumps which are used, inter alia, on dredging vessels, are exposed to the impact from mixtures of water and grains or from dredge spoil. A number of methods have been developed for investigating the performance of construction materials of this kind under impact loading, in which methods the material is accelerated with the aid of a rotor, as described, inter alia, in Annual Book of ASTM Standards, Vol. 03. 02, G 73-82"Standard Practice for liquid

impingement erosion testing".

A synchronized testing method is known from US 3, 985, 015. Recently developed methods are known from the article by W. Hübner, W. Hauffe, Wear 188 (1995) 108-114 and by Yuan Zhong, Kiyoshi Minemura, Wear 199 (1996) 36-44.

However, the possible applications for the test methods are generally limited, and the methods are often complicated. A significant problem in investigating the impact at high velocity of drops of water on a surface is the disintegration or dispersion of the drops of water when they are accelerated to high speed or are injected into a fast-moving stream of air.

SUMMARY OF THE INVENTION The known methods for accelerating granular materials and then making them collide, with the aim of breaking or comminuting, working, cleaning, sorting, testing or influencing this material in some other way, have been found to have drawbacks. For example, the efficiency of the many known methods for comminution by means of single impact, indi- rect multiple impact and direct multiple impact, is rather low, primarily owing to the chaotic nature of the methods : much of the energy supplied to the material is converted into heat, which is at the expense of the energy available for breaking. An additional drawback is the rather considerable wear to which the comminution device with which this method is carried out is exposed. The process with which the material is accelerated proceeds in a rather uncontrolled manner. The grains leave the rotor blade at different take-off velocities and at varying take-off angles, with the result that the various grains from the stream of grains can strike the stationary armoured ring, which is disposed around the rotor blade, at varying velocities and at differing angles, while the knurled, stationary armoured ring in part interferes considerably with the comminution process, which. interference increases considerably as the projecting points of the armoured ring become worn. The stream described by the accelerated grains before they strike the said armoured ring is disrupted further by rebounding fragments (interference). Impact against an autogeneous bed of the same material limits the wear but requires a relative high amount of energy and has a relative limited crushing efficiency. All the above has the result that the comminution process cannot always be controlled equally well, so that not all parts are broken uniformly.

The comminution product obtained as a result frequently has a relatively great grain size distribution and spread in grain configuration, and may contain a relatively great proportion of undesirable fine parts. Impact against an autogenous bed of the same material has only

a limited comminution effectiveness.

Methods for testing material with regard to the effect of impact loading have the drawback that these methods are not deterministic, or are deterministic only to a limited extent, thus limiting the possibilities for testing. Furthermore, it is very difficult, and often impossible, with the known test method to subject material to impact loads continuously and at varying velocities.

The object of the invention is therefore to provide a method, as described above, which does not exhibit these drawbacks, or at least does so to a lesser extent. This object is achieved by means of an essentially deterministic method for making material collide with the aid of a rotating impact member, comprising the steps : -feeding the said material to the central feed of a guide member, which rotates about the axis of rotation (O) of the said rotating system ; -guiding the said fed material from the said central feed, along the guide face, to the delivery end of the said guide member, which delivery end is situated at a greater radial distance (rl) from the said axis of rotation (O) than (ro) the said central feed, in such a manner that the said guided material comes off the said guide member with at least a radial velocity component (vr) and is guided in an essentially deterministic straight path (R), when seen from a stationary viewpoint, and in an essentially deterministic spiral stream (S), when seen from a viewpoint which moves together with the said collision means ; -using the said moving collision means to hit the said material, which is moving in the said essentially deterministic spiral stream (S) and has not yet collided, at a hit location (T) which is behind, when seen in the direction of rotation, the radial line on which is situated the location (W) where the said as yet uncollided material leaves the said guide member, and at a greater radial distance (r) from the said axis of rotation than the location (W) at which the said as yet uncollided material leaves the said guide member, the position of which hit location (T) is determined by selecting the angle (9) between the radial line on which is situated the location (W) where the said as yet uncollided material leaves the said guide member and the radial line on which is situated the location where the path (S) of the said as yet uncollided material and the path (C) of the said collision means intersect one another in such a manner that the arrival of the said as yet uncollided material at the location (T) where the said paths intersect one another is synchronized with the arrival at the same location of the said moving collision means.

The collision means may be formed by a rotating impact member, which rotates in

the same direction, at the same angular velocity and about the same axis of rotation as the guide member, which rotating impact member is provided with an impact face. The collision means may further be formed by an object or a part made of the same material. The material may be formed by a stream of granular material, a stream of liquid drops or a stream of liquid. The invention provides the possibility of using the collision means to hit a plurality of materials, optionally simultaneously.

In the method according to the invention, the grains to be broken, as is usual, are metered onto a metering face, which is disposed on the centre of a rotor, and, under the effect of centrifugal forces, are accelerated with the aid of a rotating guide member and flung away outwards, i. e."launched"in the direction of an impact member which, at a greater radial distance, rotates in the same direction, at the same angular velocity (Q) and about the same axis of rotation as the said guide member. The unit comprising rotating guide member and rotating impact member is here referred to as the rotating system. The said guide member is equipped with a central feed, a guide face and a delivery end. According to the method of the invention, each grain from the stream of material is launched in a predetermined fixed, controlled and unimpeded manner, i. e. in an essentially deterministic manner : i. e. from a predetermined take-off location (W), at a predetermined take-off angle (a) and at a take-off velocity (vabs) which can be selected with the aid of the angular velocity (S2,). As a result, the stream which the grains then describe is also fixed.

The movement executed by a grain in the process can, in effect simultaneously, be seen from both a stationary viewpoint and a viewpoint which moves together with the guide member or the rotating impact member. Although the movement which takes place in the same period of time is identical in both of these cases, the path described by the movement of the grain is extremely different when seen from the respective viewpoints.

To understand the method of the invention, it is of essential import that the movement executed by the material between the guide member and the rotating impact member is simultaneously seen from both a stationary viewpoint and from a viewpoint which moves along therewith.

-When seen from a stationary viewpoint, the grains, after they have been metered onto the rotor blade, move in a virtually straight, radially directed stream outwards, towards the outer edge of the metering face, where the stream of material is taken up by the guide member and accelerated. When the stream of material comes off the delivery end of the guide member, this stream moves along a virtually straight path and the velocity of the movement is virtually constant. This velocity is equal to the take-off velocity (rabs) with which the grains leave the guide member. The direction of the straight stream is determined

by the take-off angle (a), the grains in the plane of the rotation moving outwards, when seen from the axis of rotation, and forwards, when seen in the direction of rotation.

-When seen from a viewpoint which moves together with the rotating impact member, the grains on the metering face describe an outwardly directed, short spiral stream, approximating to an Archimedes'spiral, and from the delivery end they describe a long spiral stream, which is directed more radially outwards than the short spiral, the relative velocity of the movement increasing, when seen from the rotating impact member, as the grain moves further away from the axis of rotation. At the moment at which the grain comes off the guide member, the relative velocity is lower than the take-off velocity (vars), but it quickly exceeds the latter, whereupon the relative velocity along the spiral stream increases, and further on in the stream relative velocities can be reached which are a multiple of the direction of the movement of the spiral stream, as for the straight stream, is determined by the take-off angle (a), the grains in the plane of the rotation moving outwards, when seen from the axis of rotation, and backwards, i. e. in the opposite direction to the straight stream, when seen in the direction of rotation. After the take-off velocity (vars) has been exceeded, the grains cover a greater relative distance along the spiral stream than along the straight stream, the difference in length increasing as the grains move further away from the axis of rotation.

The function of the guide member is thus to"launch"the grains in succession, in such a manner that they are flung away in a defined stream, the"short"natural spiral stream which the grains describe on the metering face being converted, with the aid of the guide member, into a"longer"spiral stream which the grains describe between the guide member and the rotating impact member, when seen from a viewpoint which moves together with the rotating impact member.

According to the method of the invention, the accelerated granular material is not allowed to collide directly with a stationary or co-rotating armoured ring, armoured plate or bed of the same material which is disposed around the rotor, but rather the grains are first hit in their spiral stream, after leaving the guide member, by the impact face of a rotating impact member, which impact face is disposed virtually transversely in the spiral stream which the grains describe after leaving the guide member. The rotating impact member is situated at a greater radial distance from the axis of rotation than the delivery end of the guide member, from where the grains are launched. Nevertheless, the impact member rotates in the same direction and at the same angular velocity (S2) and about the same axis of rotation as the guide member, which means that the absolute velocity in the peripheral direction of the said rotating impact member is greater than this corresponding

velocity of the grains, when seen from a stationary viewpoint. The difference in the abso- lute velocity in the peripheral direction, i. e. the difference in absolute transverse velocities, between the grains and the rotating impact member roughly provides the impulse loading, under the effect of which the breaking process takes place. In addition, the grains still have a radially outwardly directed velocity component with respect to the rotating impact member, which radial velocity component is of essential importance to the accuracy with which the impacts of the grains against the collision face of the stationary impact member take place.

It can be demonstrated that, in a rotating system, the path which a grain describes, from the moment at which the said grain comes off a guide face until the moment at which the said grain strikes an impact face of a rotating impact member, is not affected by the angular velocity (Q), or the take-off velocity (Va,,), when the following conditions are satisfied : -the take-off angle (a) of the said grain on leaving the said guide member is independent of the said angular velocity () ; -the take-off location (W) at which the said grain leaves the said guide member is likewise independent of the said angular velocity (Q) ; -the said take-off velocity (vabs) of the said grain after leaving the said guide member, with regard to a viewpoint which moves together with the said rotating impact member, is proportional to the angular velocity (Q) of the said rotating impact member.

If these conditions are satisfied, then the route covered by the said grain between the said guide member and the said rotating impact member is constant. Since the said distance is constant, and since the said distance is the product of the constant velocity (vab5) and the time (t) elapsed, and the said velocity (rabs) is proportional to the said angular velocity (Q), the said elapsed time (t) is inversely proportional to the said angular velocity (Q). Since the peripheral velocity (V, ip) of the said rotating impact member is also proportional to the said angular velocity (Q), the route covered along the periphery, which the said rotating impact member describes, is not affected by the angular velocity (Q) in the said elapsed time (t).

This demonstrates that the route covered by both the said grain and the said rotating impact member is always constant in relation to the said angular velocity ().

This makes it possible to synchronize the movement executed by the rotating impact member with the movement executed by the grain, so that, irrespective of the angular velocity (Q), the impact of the grain against the impact face of the rotating impact member takes place at a predetermined synchronization location (T) and at a predetermined impact angle (p), the impact velocity (V iiiipact) being proportional to the angular velocity (Q) and

can thus be selected with the aid of the said angular velocity (Q) without in so doing affecting the impact location (T) or the impact angle (p).

It can be demonstrated that synchronization of this kind is even possible if at least two streams, which are directed at an imaginary impact face, are launched from a system which rotates at the angular velocity, at least one of the said streams acting as collision means for the other streams.

For the sake of completeness, it should be noted that the friction between the grain and the guide face, which is given by the coefficient of friction (co), is affected slightly, although minimally, by the angular velocity (Q), and as such slightly affects the take-off angle (a) and the take-off velocity (v). However, this effect is so minimal that it can be disregarded here. However the friction as such has to be taken into account.

In order to satisfy the abovementioned conditions, the grains therefore have to leave the guide member, irrespective of the angular velocity (Q), at the same location and at the same take-off angle (a), when seen from a stationary viewpoint, the take-off velocity (vab5) may only be affected by the angular velocity () and the movement of the grains along the stream may not be substantially affected by the air resistance and air movement ; i. e. both the way in which the grains leave the guide member and the stream which the grains then describe must be essentially deterministic.

In theory, the grains can be guided (launched) in a deterministic manner in a deterministic stream of this kind for any take-off velocity (vars) and at any take-off angle (a) between 0° and 90° : with an extremely short rotating impact face with a take-off angle (a) of approximately 0° in a straight tangential stream, and with a spiral (Archimedes' spiral) guide member with a take-off angle (a) of approximately 90° in a straight radial stream, when seen from a stationary viewpoint. However, in reality the possibilities are limited, and certain conditions have to be met with regard to the take-off velocity (vau5) and the take-off angle (a), while the effect of air movements has to be limited as far as possible.

-In order to bridge the relatively short distance between the guide member and the rotating impact member without the force of gravity and the air resistance significantly affecting the movement of the grains, a take-off velocity (vab5) of 10 to 15 metres per second is normally sufficient for grains with diameters of greater than 3 to 5 mm. At lower velocities, the movement of the grain is increasingly affected by both the air resistance and the force of gravity, with the result that the spiral paths described by the grains start to shift in an uncontrolled manner. For smaller diameters, the influence of the air resistance increases considerably, essentially irrespective of the velocity, and in order for the process to proceed in an essentially deterministic manner it is necessary to create a vacuum in the chamber

between the guide member and the rotating impact member.

-The effect of the air movements which are generated by the rotating guide member and the rotating impact member can be limited by setting in motion, at the same time as the grains, an air stream, which has virtually the same velocity as the grains, with the aid of the guide member along the spiral stream, so that, as it were, a cylindrical disc (flying dish) of air is formed between the guide member and the rotating impact member, this air rotating in virtually the same direction, at virtually the same angular velocity (Q) and about the same axis of rotation as the guide member and the rotating impact member.

-In order to allow the separate grains from the stream of grains to come off the guide member from virtually the same location and at virtually the same take-off angle (a), irrespective of the angular velocity (S2), with only the take-off velocity (rabs) being affected by the angular velocity (Q), it is necessary for the grains to be taken up in a regular manner by the central feed of the guide member, making good contact with the guide face in the process, so that the grains are guided to the delivery end over a certain distance along the guide face, so that the radial and transverse velocity components of the individual grains from the stream of material, at the moment at which they reach the delivery end and come off the guide member, are virtually constant. To achieve this, the length of the guide face has to be selected such that the radial velocity component (vr) at the location of the delivery end is at least 35% till 55 % of the transverse velocity component (v,), i. e. so that the take- off angle (a) is greater than or equal to 20°, and preferably 30°. A shorter guide face leads not only to a shorter take-off angle (a), but is also the cause of the grains starting to come off the guide member at varying take-off velocities (vabS) and at different take-off angles (a), and in the process even the location where the grains come off can shift. The shorter the guide is chosen to be, such that the take-off angle (a) becomes less than 30°, the more chaotic the process becomes.

Thus, in order to realize the abovementioned conditions in practice, the said material has to be accelerated along the said guide face in such a manner that, when the said material is taken from the said delivery end in a straight stream, the said take-off velocity (vars) is at least 10 metres per second, and preferably at least 15 metres per second, and the take-off angle (a) is at least 20°, and preferably at least 30°, when seen fi om a stationary viewpoint.

The maximum take-off angle (a) is normally limited in practice to 45°, so that the feasible range in which the grains can be guided in an essentially deterministic stream from the guide member to the rotating impact member irrespective of the angular velocity (Q) lies between the take-off angles (a) of 30° and 45°. This places certain requirements on the guide member.

After the granules have been metered onto the rotating metering face close to the axis of rotation, they move outwards in a virtually radial direction, when seen from a stationary viewpoint, and outwards in a spiral stream, when seen from a viewpoint which moves together with the face, which spiral movement normally approximates to an Archimedes' spiral.

The movement of the stream of material moving outwards, from the metering face, along the said spiral is interrupted by the guide member, which is normally arranged in the spiral at a distance from the axis of rotation. That part of the guide face of the guide member which intersects the stream of material is referred to as the central feed. This central feed forces the material stream to move in a more radial direction, with the result that the movement is accelerated. The length (foc) from the start point to the end point of the central feed is thus determined by the shape of the spiral stream of material, and as such is a function of the angular velocity (S2) at which the guide member is rotating, the radial velocity (va) of the material at the moment at which it touches the central feed and the number of guides (ng), which radial length () essentially satisfies the equation : <BR> <BR> <BR> <BR> <BR> e =% Va<BR> <BR> <BR> c Q # All notations used in the text are summerized at page 101.

The length (8c) of the central feed therefore increases at lower angular velocities (IT) and greater initial radial velocities (va) ; the latter being a function primarily of the way in which the material is metered (height of drop) and the shape of the metering face. It is important that the length of the central feed, which, after all, is not completely effective for accelerating the material in the radial direction, is kept as short as possible. This is achieved by allowing the system to rotate at a sufficiently great angular velocity (Q) and keeping the initial radial velocity (va) as low as possible, i. e. as far as possible limiting the height of drop from which the stream of material is metered onto the metering face. Furthermore, the shape of the central feed can be selected in such a manner that the stream of material is taken up as well as possible by the guide member ; this matter will be dealt with later in the text.

In order to promote a good feed of the metered material to the central feed, it is furthermore preferred to provide the grains with a preliminary guidance, in the direction of a central inlet of the guide member, from the said rotating face with the aid of a preliminary guide member, which extends from a central inlet in a direction opposite to the direction of

rotation of the rotating face towards a discharge end. It is preferred here for the guide face of the said preliminary guide member as far as possible to approximate to the natural spiral movement, i. e. Archimedes'spiral, which the said material describes at that location, or at least for the said central inlet and the said discharge end of the said preliminary guide member to lie on the natural movement spiral described by the material ; i. e. for the radial distance from the discharge end of the preliminary guide member to the axis of rotation to be approximately 10 to 15% greater than the corresponding radial distance to the central inlet of the preliminary guide member.

From the central feed, the material is taken up by the guide face and moves outwards along the latter, under the effect of centrifugal force, during which movement the material is accelerated. As has been stated, it is important that in the process the material makes good contact with the guide face. The guide face has to be at least sufficiently long for the grains to leave the guide member from a delivery end always at the same take-off location (W) and always at the same take-off angle (a), irrespective of the angular velocity (fol). A lower take-off velocity (vars) results in a higher impact velocity (Vlaact, but the take-off velicity (vau5) has to be at least 10 m/sec. The function of the guide member is thus to guide the grains at as low a velocity as possible in an essentially deterministic spiral stream. The aim is to achieve direction, and not so much to achieve velocity.

It is furthermore important that no more material is added to the guide members than the amount which the latter are able to deal with in an essentially deterministic manner ; i. e. that the grains come off the guide member essentially in succession (virtually one by one) and that the impacts are not disrupted by interference. This so-called essentially deterministic capacity is determined by the grain diameter and, of course, by the angular velocity (Q) and the length of the guide face. The deterministic capacity decreases considerably for smaller grain diameters. This is balanced by the fact that it is possible, in the case of smaller grain diameters, to design the rotor blade with more guides, so that the essentially deterministic capacity of the rotor blade as a whole is not affected excessively.

Starting from a radially arranged guide face, the minimum length of the guide face which is required in order to make the grains come off the guide member in an essentially deterministic manner is, for a resistance-free state given by the relationship between the radial distance from the axis of rotation to the central feed and the corresponding radial distance to the delivery end, i. e. (rC/rl) which ratio essentially satisfies the equation :

To achieve a take-off angle (a) of 30° the ratio rC/rl =-25%, and for 20° the ratio r/ rl =-10%. In the event of a different coefficient of friction and in the event that the guide face is not arranged radially and is not straight, but rather is of curved design, the relationship between the said radial distances has to be adapted.

In the event that the guide face is not arranged radially, or is curved, the relationship can also be calculated ; however, this calculation is complicated, but essentially satisfies the equation : cos Ot, p r12-r2 cosao-r/ oc = arctan ri-sinao-r/J All notations used in the text are summerized at page 101.

If the delivery end is positioned towards the rear, when seen in the direction of rotation, a greater radial velocity component (v) is generated by comparison with a radial arrange- ment of the guide face, while the transverse velocity component (v) decreases slightly, resulting in a greater take-off angle (a). This makes it possible, while retaining the prescribed take-off angle (a), to make the radial distance from the delivery end to the axis of rotation shorter. Conversely, if the delivery end is positioned towards the front, the opposite is the case. It is therefore possible to achieve the prescribed take-off angle (a) with a relatively short radial distance from the axis of rotation to the delivery end, making it possible to reduce the take-off velocity (vars).

In the case of a radially arranged guide member, the central feed is directed virtually perpendicular to the short spiral stream which the material describes on the metering face.

The movement of this stream, at the location of the central inlet, therefore has to form an angle of approximately 90°, which can lead to blockage, with the result that the flow rate from the guide member is limited. It is therefore preferred to curve the central feed and to position it with the entry in line with the short spiral stream, as a result of which the material is taken up and guided to the guide face in a better and more natural manner. Since there is only a limited take-off velocity (vau$), of approximately 10 metres per second, the guide face can be designed with a straight face which is directed obliquely backwards, when seen in the direction of rotation. From the guide face, the stream of material is guided towards the delivery end, from where the material is guided in an essentially deterministic, long spiral stream. The said delivery end may be bent backwards, when seen in the direction of rotation, so that the grains are guided, as it were, in a natural manner

from a location on the said delivery end in the intended, essentially deterministic spiral stream, in the direction of the rotating impact member. An essentially S-shaped"grain pump"of this kind makes it possible to convert the movement of the stream of material in as natural a manner as possible, and thus with minimum energy and wear, from a short spiral into an essentially deterministic long spiral.

The grains advancing in an essentially deterministic spiral stream are now hit for the first time, specifically by the impact face of the rotating impact member, which impact is likewise essentially deterministic, specifically such that, irrespective of the angular velocity (H), the hitting takes place at a predetermined hit location (T), at a predetermined impact angle (p) and at an impact velocity (V ) which can be specified and can be controlled with the aid of the angular velocity (Q). For this purpose, the angle (0) between the radial line on which is situated the location at which the said as yet uncollided stream of material leaves the guide member and the radial line on which is situated the location at which the stream of the as yet uncollided material and the path of the said rotating impact member intersect one another has to be selected in such a manner that the arrival of the said as yet uncollided stream of material at the location at which the said stream and the said path intersect one another is synchronized with the anival at the same location of the rotating impact member.

A plurality of guide members with associated impact members can be disposed around the axis of rotation. Since the synchronously running steps of accelerating and striking the material form essentially individual processes for each of the arrangements, these processes can be differentiated by changing the position of the guide member and/or the rotating impact member for each arrangement, in which case the principle of differentiation is referred to. A differentiated arrangement of this kind makes it possible for the separate breaking processes to take place simultaneously but at different collision velocities or impulse loading. As a result, a differentiated arrangement of the impact members leads to the production of materials of differing fineness, with the result that the grain size distribution of the broken product can be controlled to a considerable extent. This can be achieved by varying only the radial distances to the various locations where the grains leave the guide member amongst themselves or, and this is the preferred option, by arranging the rotating impact member at a different location, or at a different distance from the axis of rotation, in the spiral stream described by the grains.

Futhermore it is possible to vary the amount of material which is fed to the various guide members. The guide members as it were divide the rotor blade into feed segments.

Normally, the guides are arranged at regular intervals and at the same radial distances from

the axis of rotation. In this case, the feed segments are of equal sizes and the stream of material is distributed uniformly over the guide members. However, it is also possible to make the size of the feed segments different. This is known as the principle of segmentation.

An irregular segmentation of this kind may, for example, be achieved by arranging the start points of the central feed ends of the guide members at different radial distances from the axis of rotation. The guide members which are disposed with the central feed closer to the axis of rotation now take up more material than the guide members whose central feed is further away from the axis of rotation. Such segmentation of the material makes it possible to regulate further the amounts of material which are broken into fine and coarse particles. Naturally, segmentation is also possible with the aid of the preliminary guide members.

To obtain the desired result, i. e. the desired collision between grains and the rotating impact member, the angle (6) between the radial line on which is situated the location where the material leaves the guide member and the radial line on which is situated the location where the material is hit by the impact face, with the aid of the rotating impact member, must essentially satisfy the equation : p cos a cos a 0 = arctan psina+rl f r where : vabs cos α<BR> <BR> <BR> f = -<BR> vtip All notations used in the text are summerized at page 101.

It is necessary here to take into account the grain diameter. The further the grain diameter increases, the longer the grain makes contact with the guide face at the location of the delivery end, resulting in a greater transverse and, in particular, radial velocity compo- nent, and consequently a greater take-off angle (a) and a greater take-off velocity (vau5).

The influence is in any case limited, but is the cause of a natural shift, which is per se deterministic, of the spiral stream for larger and smaller grains. The radial distance to that location at which the material leaves the guide member (rl) is therefore calculated as the sum of the corresponding radial distance to the delivery end of the guide member, increased by half the diameter of the grains from the material.

Since the angle (0) has an unambiguous relationship with the radial distance (r) from the axis of rotation to the hit location (T), it is in fact possible to dispose the impact face at precisely the correct location, i. e. in a synchronized manner.

In order to achieve an effective collision between particle and the impact face of the rotating impact member, it is preferred for the angle (8) to be greater than 10° ; preferably greater than 20° to 30°. The maximum angle (0) is essentially limited only in practical terms, but may even be greater than 360°.

It is possible to guide the material, after it has struck the first impact face and comes off the latter, in a second spiral path to a second, co-rotating impact face, and then allowing it to strike a stationary impact member. This method has the advantage that the material is accelerated by means of two impacts, with the result that, while the wear is distributed over the two impact faces, the material can be brought to a very high velocity. Furthermore, as explained above, directly successive impacts lead to a considerable increase in the probability of breaking. The collision velocity with which the particles can be loaded during the successive impacts can be controlled with the aid of the positioning, i. e. the radial distances to the axis of rotation, of the respective impact faces. This multiple impact- loading method is particularly advantageous for processing material which is composed of components which have very different hardnesses (brittlenesses) in order to release miner- als from ores and in order to comminute material to a very great fineness.

In the calculation, a resistance-free state is assumed. In reality, the movement of the grains is in actual fact subject to, inter alia, friction against components of the rotor and to the air resistance. The same applies to the force of gravity. In this calculation, a role is played by the grain diameter, the grain configuration and the self-rotation of the grains.

These parameters have a certain influence on the stream, although without changing the nature of the movement significantly. However, this influence is generally limited for the limited distance between the guide member and the rotating impact member, which is covered at high speed by the grains, and thus in a very short period of time (normally 30- 60 ms), although the influence cannot be ignored altogether. Furthermore, we have to deal with the influence of air movements which are caused by the rotation of the system. These may be limited by forming a type of rotating (flying) dish of air in the space between the guide member and the rotating impact member, so that the air rotates together with the guide members and the impact members.

Different grains from one stream of material can therefore describe different paths next to one another, owing to a natural, but essentially deterministic shift, with the result that the grains do not all hit precisely the same location on the rotating impact member.

Although the effect is normally limited, it is necessary in practice, when positioning, dimensioning and selecting the rotating impact member, to take into account the fact that the impacts can to some extent spread over a certain region on the impact face because of natural effects. As we shall see later, this is in itself beneficial, since the wear is thus also spread along the impact face.

As well as the hit location, it is also possible to specify the angle (p) at which the grains hit the impact face of the rotating impact member in a fairly accurate manner. At the location where the said as yet uncollided material hits the said impact face, the said impact face, together with the line which is directed perpendicular to the radial line on which is situated the location at which me said material leaves the said guide member, forms an impact angle (p'), when seen in the plane of the rotation and when seen from a viewpoint which moves together with the said rotating impact member, which angle essentially satisfies the equation : 2 f 1 r cosa rcosm rl cos oc fr, f rl p sin a + rl = arctan-6 rlsina + p where : posa cossa 6 = arctan psinO+rl f r p cos a p = arctan psino+rlJ All notations used in the text are summerized at page 101.

With the aid of the angle (ß'), it is in fact possible to curve and arrange the impact face in such a manner that different grains from the stream of material all strike the impact face of the rotating impact member at an angle which is as far as possible identical, which impact angle (p) preferably lies between 75° and 85°.

In order as far as possible to limit the wear to the said impact face of the said rotating impact member, it is necessary to prevent the said material from moving outwards along the said impact face after impact ; i. e. to prevent the said impact face starting to function as

a"guide acceleration member"in addition to as an"impact acceleration member". This leads, at the relatively great radial distance from the axis of rotation on which the said rotating impact member is disposed and the associated high peripheral speed at that location, to an extremely high level of wear along the outer edge of the said rotating impact member ; which guide acceleration and guide wear do not contribute significantly to an improved progression of the comminution process. By directing the said impact face slightly (a few degrees) inwards, when seen in the plane of the rotation, at an angle (p"), with respect to the position directed perpendicular to the said spiral stream of the said material, and directing the said impact face slightly (a few degrees) downwards, in the plane directed perpendicular to the plane of the rotation, at an angle (ß"'), the said material can be guided downwards, as far as possible perpendicularly along the impact face, after impact, provided it does not rebound, where it comes off along the edge of the said impact face of the rotating impact member : in which case there is no significant centrifugal acceleration, so that the wear on the guide remains limited to a minimum and interference is prevented, since the impact face is immediately free for the impact of the said following material. The calculated angle in fact makes an arrangement of this kind possible.

The precise velocity at which the grains hit the impact face of the rotating impact member, i. e. the actual impact velocity (V, bnpact) is a function of, on the one hand, the radial distance from the axis of rotation to the central feed end of the guide member, the corresponding radial distance to the location from which the grains leave the guide member and the location at which the grains hit the impact face and, on the other hand, the angular velocity (Q) of the guide member and of the rotating impact member, and essentially satisfies the equation : 2 2' Vunpact-r +r 8 where : p cos a (p = arctani P p sin a+rl

All notations used in the text are summerized at page 101.

It is therefore possible, for a defined angular velocity (Q), successively to select the radial distance from the axis of rotation to the central feed end of the guide member, the radial distance from the axis of rotation to the location where the as yet uncollided grains leave the guide member, and the radial distance from the axis of rotation to the location where the as yet uncollided grains are hit for the first time by the rotating impact manner, such that the as yet uncollided grains are hit for the first time by the rotating impact member at a prescribed impact velocity (Vhnpact).

It is also possible, for a guide member with a defined radial distance from the axis of rotation to the central feed end of the guide member, a defined radial distance from the axis of rotation to the location where the as yet uncollided grains leave the guide member, and a defined radial distance from the axis of rotation to the location where the as yet uncollided grains are hit for the first time by the rotating impact member, to select the angular velocity (Q) such that the grains are hit for the first time by the rotating impact member at a prescribed impact velocity (Vhl. pac) As has been stated, the high level of determinism of the method of the invention for making material collide has the consequence that the impacts against the said impact face of the said rotating impact member can take place in a relatively concentrated manner.

This may be the cause of problems. If the impacts against the impact face of the breaking member take place in an excessively concentrated manner, this may lead to a non-uniform wear pattern along this face, with the result that the breaking process can be disturbed significantly. However, as explained above, there is normally a natural, although limited, spread and shift of the deterministic spiral paths which the separate grains of the said material run through ; for example due to the fact that grains with a large grain diameter make contact for a longer period with the guide member than grains with smaller diame- ters, and thus leave the delivery end at a slightly different take-off angle (a) and take-off velocity (vau5). Furthermore, the air resistance, the air movements and even the force of gravity will to some extent affect the movement of the separate grains. In addition to the grain diameter, the shape of the grain, the grain configuration and the self-rotation of the grain also have an effect here. The fact that the spiral movement also exhibits a certain

shift as a result of wear along the guide face and the impact face will be dealt with subsequently. Thus there is normally a natural, outwardly widening spiral bundle of paths, which is otherwise still essentially deterministic.

However, it may also prove necessary to take measures to ensure that the impacts spread out to a greater extent across the impact face. An artificial shift of the location, i. e. the limited area where the said material from the said spiral stream hits the said impact face, may be of essential import ; in particular when the natural spread is limited and when the grains become very pulverized during the first impact and the fragments are not removed from the location of the said impact quickly enough (this occurs in particular in the event of the impact of very tough material), with the result that the intensity of the following impacts is limited (damped), in which case interference is involved. A regular shift of this kind can be achieved by allowing the position of the delivery end of the guide member to move slightly, when seen from a viewpoint which moves together with the rotating impact member. A relatively small movement of the delivery end, as stated above, quickly leads to a greater displacement further on in the spiral stream. The delivery end can be moved in a relatively simple manner by arranging the guide member pivotably along the edge of the rotating face, in such a manner that the delivery end, in the plane of the rotation, executes a slight reciprocating movement along the circumference which the delivery end describes, when seen from a viewpoint which moves together with the rotating impact member ; the invention provides for this possibility.

On the other hand, it may happen that the spiral streams along which the grains are guided to the rotating impact member become somewhat excessively spread, with the result that some grains from the stream of material hit the impact face on the edge or fly right past it. The method of the invention therefore provides the option of a subsequent guide member which can be disposed, between the guide member and the rotating impact member, along a section of the intended spiral stream ; preferably along the outside, when seen from the axis of rotation. It is in any case possible actively to involve the subsequent guide member in providing subsequent guidance for the grains, by allowing the subsequent guide face of the subsequent guide member to intersect slightly the spiral stream of the grains.

Owing to wear on the guide face, and in particular on the delivery end, of the guide member, the spiral stream between the guide member and the rotating impact member shifts gradually backwards, when seen in the direction of rotation, with the result that the location of the impact on the impact face of the rotating impact member also shifts. It is necessary to prevent the delivery end being able to become worn to such an extent that the

impact face is no longer hit by all the grains from the stream of material. It is possible to adapt the wear along the guide member and on the rotating impact member, i. e. to integrate this wear, in such a manner that in the event of wear to the guide member the rotating impact member always lies in the spiral stream of the said material. This is known as the principle of integration, although this principle cannot be summarized by a formula ; however, it can be simulated using a computer. Together with practical observations, this makes it possible to mutually adapt the design and the geometry of the guide member and the rotating impact member to the shift backwards, when seen in the direction of rotation, of the said spiral stream through which the said material runs between the said guide member and the said rotating impact member, when seen from a viewpoint which moves together with the said rotating impact member, which shift arises as a result of wear to the said guide face and in particular to the said delivery end, and specifically to adapt them such that, in the event of wear to the said guide member, the said impact face always lies in the said spiral stream of the said material.

As has been stated, the impact of a grain from the steam of material against the impact face of the rotating impact member can be impeded by other grains or fragments which are formed from these grains during the impact. This occurs in particular if grains are pulverized during the impact, in which case the very fine particles, in particular if they are moist, may adhere to the rotating impact face. As indicated earlier, this can be partially prevented by disposing the rotating impact face at an oblique angle, inwards and downwards, with res- pect to the impacting stream of material. The method of the invention furthermore provides the possibility of guiding a jet of air, in the vertical direction from the top downwards, at great speed against the rotating impact face, with the result that the impact face is continuously blown clean. The jet of air can be generated with the aid of the rotating movement of the rotating impact member, by disposing a partition or pipe, directed obliquely downwards, along the top of the edge of the rotating impact member.

In contrast to the known method, in which the material is flung from the guide member directly against a stationary impact member, essentially no velocity remaining after the stationary impact, the said material leaves (rebounds from) the rotating impact member after the impact with a rebound or residual velocity (VraSjdual) which is at least as great as the peripheral velocity (tip velocity (V, ip)) of the rotating impact member, which velocity, depending on the coefficient of restitution, is frequently greater (5-15%) than the impact velocity (V iinpact). This residual velocity (Yidua further utilized by allowing the material then to strike the collision face of a stationary impact member, which collision face is disposed in the straight stream which the material describes after it has struck the

rotating impact member and come off the latter, when seen from a stationary viewpoint.

The stationary impact member can be formed by at least one collision face. The stationary impact member can be made with a collision face of hard metal, which collision face is directed virtually transversely to the straight stream which the said material which has collided once describes when it comes off the said rotating impact member, when seen from a stationary viewpoint. The stationary impact member can also be formed by a collision face, which is formed by a bed of the same material, which collision face is directed at the straight stream which the said material which has collided once describes when it comes off the said rotating impact member, when seen from a stationary viewpoint.

In this case, the stream of material is split by the first and second guide members into two part streams, which are launched at different locations and at different velocities.

Depending on the radial distance and the angular distance of the"launching locations", the two part streams hit one another at a point in the chamber which is situated radially further outwards, thus resulting in a so-called"autogenous"breaking process, i. e. a breaking process in which the particles themselves each form the collision means (impact member) for the other. The invention provides the possibility of carrying along different materials with the separate part streams.

An autogenous breaking process of this kind can furthermore be carried out by causing material to collide with an autogenous bed of corresponding material after the two porti- ons of the material have collided with one another, which autogenous bed is disposed around the outside of the rotor, at a radial distance which is greater than the radial distance at which the streams of grains strike one another.

The collision face of the stationary impact member can be designed in such a manner that the separate grains impact at an angle which is as uniform as possible. For this purpose, the said collision face has to be curved and arranged in such a manner that the impacts, when seen from the plane of the rotation, take place as far as possible perpendicularly ; and when seen from a plane perpendicular to the plane of the rotation, at an angle which is optimum for the loading of the material, normally lying between 75° and 85°, and preferably between 80° and 85°. This is possible both for a collision face made of hard metal and for a collision face which is formed by a bed of the same material.

The fact that the said impacts take place regularly, immediately in succession and at an angle which is as optimum as possible leads to a very great loading intensity on the grains and a correspondingly high breaking probability, while the wear is limited as far as possible.

A second impact against a collision face made of the same material allows a very

intensitive autogenous (after) treatment of the said material which has collided once.

Compared to known systems, in which the grains are introduced into the autogenous bed in the plane of the rotation, i. e. virtually horizontally, the method according to the invention has the advantage that the material can be guided from the said impact face which is also moving, at relatively great speed, into the said autogenous bed, obliquely from above, thus considerably enhancing the intensity of the autogenous treatment. Furthermore, it is possible to arrange the collision face in such a manner that an autogenous bed of the same material is built up, arranged virtually transversely in the straight stream of granules, thus enhancing the autogenous intensity still further. The collision face of the autogenous bed may thus be disposed in such a way that the grains are guided into the bed in a virtually horizontal direction or obliquely from below ; this may, depending on the breaking behaviour of the material, be prefened.

The method of the invention thus makes it possible to bring granular material from a predetermined location on the guide member, at a predetermined take-off angle (a > 30°) and at a relatively low take-off velocity (vau5) (> 10 metres per second) into a deterministic spiral stream and then to allow the said material to strike at great speed against an impact face, disposed transversely further on in the spiral stream, of a rotating impact member, which rotates in the same direction, at the same angular velocity (Q) and about the same axis of rotation as the guide member. The impact face of the said rotating impact member can be positioned in such a manner that the impact takes place at a predetermined hit location (T), at a predetermined impact angle (p), at a predetermined impact velocity (V ;" ), which impact velocity (V ) can be selected accurately, within very wide limits, with the aid of the rotational speed (Q), without the location of impact and the angle at which the impact takes place being affected. This high residual velocity (Vresidua,) which the grains still possess after they come off the rotating impact member, i. e. approximately half of the comminution energy, can be utilized further for a second impact of the material against a stationary collision face or a bed of the same material.

In the method according to the invention, the material is thus accelerated in two steps, short guidance followed by impact while moving along, while the said material is simultaneously loaded in two, immediately successive steps, co-rotating impact immediately followed by stationary impact, the second impact taking place at an collision velocity (V) which is at least as great as the velocity at which the first impact (Vimpact) takes place. Both the two acceleration steps and the two loading steps, which overlap one another, proceed in an essentially deterministic manner, with the result that as little energy as possible is lost, the wear remains limited and the loading intensity is very great and regular. The

method of the invention thus leads to a very great, and essentially deterministic, collision intensity with a relatively low power consumption and a relatively low level of wear.

However, the method according to the invention is not suitable solely for crushing material. According to another possibility, the collision means (impact member) may form an object which is deliberately exposed to a series of impacts from material, for example in order thus to treat the surface of the said object. Consideration may be given here, inter alia, to a treatment process which is similar to (sand) blasting. Other treatment processes relate to the application of a layer of material of a different type to the surface of an object, optionally with the aim of prestressing this object. It is also possible to treat the surface, for example by touching up weld seams or repairing microcracks along the surface. Also, the surface, or the object, can be shaped and even deformed.

In order to treat an object in such a manner, the invention provides the possibility of allowing this object to perform a rotationally symmetrical movement and optionally of being vertically adjustable during the rotating movement. As has been stated, the invention also provides the possibility of using this method to set the comminuted stream of material in motion ; this possibility may be used, for example, for sand-blasting.

Furthermore, the method of the invention is eminently suitable for testing the impact hardness (brittleness) of materials, and also for testing the surface of an object under im- pact loading. Consideration may be given here to testing construction materials destined for aircraft and for turbine blades. Materials which can be used for this are granular material, a mixture of granular material and a liquid, i. e. a slurry, and a liquid. For this purpose, the stream of liquid must be brought to only a relatively low velocity, so that dispersion of the liquid is limited. As the liquid, consideration may be given to drops or a stream of liquid.

Finally, the method of the invention provides the possibility for the collision of the material to take place in a chamber in which both the temperature and the pressure can be controlled, so that the process may take place at high and low temperatures and high and low (partial vacuum) pressures.

The method of the invention makes possible a device for breaking granular material, comprising : -at least one rotor which can rotate about a central vertical axis of rotation (O) ; -at least one guide member, which is supported by the said rotor and is provided with a central feed, a guide face and a delivery end, for respectively feeding, guiding, accelerating and delivering the said stream of material which, in a region close to the said axis of rotation (O), is metered onto the said rotor, which guide member extends in the direction of the external edge of the said rotor ;

-at least one impact member, which is associated with the said guide member and can rotate about the said axis of rotation (O), which rotatable impact member is equipped with an impact face which lies entirely behind, when seen in the direction of rotation, the radial line on which is situated the location (W) where the said as yet uncollided stream of material leaves the said guide member, and at a greater radial distance from the said axis of rotation (O) than the location (W) at which the said as yet uncollided stream of material leaves the said guide member, the position of which impact face is determined by selecting the angle (9) between the radial line on which is situated the location (W) where the said as yet uncollided stream of material leaves the said guide member and the radial line on which is situated the location where the said essentially deterministic stream (S) of the said as yet uncollided stream of material and the path (C) of the said impact face intersect one another in such a manner that the arrival of the said as yet uncollided material at the location where the said stream (S) and the said path (C) intersect one another is synchronized with the arrival at the same location of the said impact face, which impact face is directed virtually transversely, when seen in the plane of the rotation, to the spiral stream (S) which the said as yet uncollided material describes, when seen from a viewpoint which moves together with the said rotatable impact member.

The method of the invention for making material collide in an essentially deterministic manner offers a considerable number of interesting possibilities for practical applications.

The discussed objectives, characteristics and advantages of the invention, as well as others, are explained, in order to provide better understanding, in the following detailed description of the invention in conjunction with the accompanying diagrammatic drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 diagrammatically shows, in steps, the progress of the method of the invention. Figure 2 diagrammatically shows a top view with a diagrammatic curve of the movement of the material according to the method of the invention, when seen from a stationary viewpoint.

Figure 3 diagrammatically shows a top view with a diagrammatic curve of the movement of the material according to the method of the invention, when seen from a moving viewpoint.

Figure 4 diagrammatically shows the transition from the short spiral to the long spiral for increasing length of the guide member.

Figure 5 diagrammatically shows a top view with a diagrammatic curve of the movement of the material according to the method of the invention, when seen from a stationary and a moving viewpoint.

Figure 6 diagrammatically shows the synchronization of the stream of material and the path which the rotating impact member describes.

Figure 7 and Figure 8 diagrammatically show a first possibility of how, according to the method of the invention, material is made to collide in a rotating system.

Figure 9 diagrammatically shows how the broken fragments, which are formed when a grain breaks during the impact against a rotating impact member (14), behave.

Figure 10 shows a separating plate for classifying and sorting material.

Figure 11 diagrammatically shows a first possibility according to the method of the invention equipped with a separating member.

Figure 12 and Figure 13 diagrammatically show a second possibility according to the method of the invention for making material collide.

Figure 14 diagrammatically shows a third possibility according to the method of the invention for making material collide.

Figure 15 and Figure 16 diagrammatically show a fourth possibility according to the method of the invention for making material collide.

Figure 17 and Figure 18 diagrammatically show a fifth possibility according to the method of the invention for making material collide.

Figure 19 diagrammatically shows a sixth possibility according to the method of the invention for making material collide.

Figure 20 diagrammatically shows a straight guide member with central feed, guide face and delivery end.

Figure 21 diagrammatically shows a bent guide member with central feed, guide face and delivery end.

Figure 22 diagrammatically shows the spiral movement which the material describes on the rotor and the transition of this spiral movement to a radial movement.

Figure 23 diagrammatically shows the way in which the material from the rotor is taken up by the central feed.

Figure 24 diagrammatically shows a movement along an Archimedes'spiral.

Figure 25 diagrammatically shows a method of calculating the length of the central feed.

Figure 26 diagrammatically shows the spiral stream which the material describes on the rotor at a relatively low angular velocity.

Figure 27 diagrammatically shows the spiral stream which the material describes on the rotor at a relatively high angular velocity.

Figure 28 diagrammatically shows a metering means, with which the height of drop of the material onto the rotor can be limited.

Figure 29 diagrammatically shows the effect of the length of the guide member on the way in which the stream of material comes off the guide member.

Figure 30 diagrammatically shows the theoretical relationship between the radial length to the central feed and the delivery end of the guide member as a function of the take-off angle for a radially disposed guide face.

Figure 31 diagrammatically shows the theoretical relationship between the radial length to the central feed and the delivery end of the guide member as a function of the take-off angle for a bent guide face.

Figure 32 diagrammatically shows the graph of the relationship between the radial length to the central feed and the delivery end of the guide member as a function of the take-off angle for a radially disposed and bent guide face.

Figure 33 diagrammatically shows the effect of the friction on the spiral movement described by the material after it comes off the guide member.

Figure 34 diagrammatically shows the spiral movement and the movement along straight guide faces which are disposed radially and non-radially.

Figure 35 diagrammatically shows a grain at the instant at which it comes off the delivery end, for a guide face which runs straight towards the rear.

Figure 36 diagrammatically shows a grain at the instant at which it comes off the delivery end, for a radially disposed guide face.

Figure 37 diagrammatically shows a grain at the instant at which it comes off the delivery end, for a guide face which runs straight forwards.

Figure 38 diagrammatically shows a rotor with S-shaped guide members.

Figure 39 diagrammatically shows an S-shaped guide member.

Figure 40 diagrammatically shows an S-shaped guide member.

Figure 41 diagrammatically shows how the central feed, the guide face and the delivery end can be designed such that they are combined.

Figure 42 shows a central feed which is disposed separately from the guide face.

Figure 43 diagrammatically shows a rotor which is equipped with preliminary guide members.

Figure 44 diagrammatically shows the velocities of the movement which the stream of material develops when it comes off the guide member, when seen from a stationary

viewpoint.

Figure 45 diagrammatically shows the velocities of the movement which the stream of material develops when it comes off the guide member, when seen from a viewpoint moving along.

Figure 46 diagrammatically shows the method of calculating the instantaneous angle (0)- Figure 47 diagrammatically shows the movement of the grain when it is moved into a second, spiral path.

Figure 48 diagrammatically shows the velocities which the stream of material develops after it comes off the guide member, along the spiral path.

Figure 49 diagrammatically shows the method of calculating the velocity (VPact) at which the material hits the rotating impact member.

Figure 50 diagrammatically shows the relative velocities which the stream of material develops along the spiral stream.

Figure 51 diagrammatically shows the method of calculating the angle (ß') at which the stream of material strikes the rotating impact member.

Figure 52 diagrammatically shows the behaviour of the stream of material after it has struck the rotating impact member.

Figure 53 diagrammatically shows the angle (ß") at which the impact face of the rotating impact member can be arranged in the vertical plane.

Figure 54 diagrammatically shows the angle (p'") at which the impact face of the rotating impact member can be arranged in the horizontal plane.

Figure 55 diagrammatically shows a top view of an air-guidance member.

Figure 56 diagrammatically shows a side view of an air-guidance member.

Figure 57 diagrammatically shows a front view of an air-guidance member.

Figure 58 diagrammatically shows the effect of the grain dimension on the spiral movement which the material describes when it comes off the guide member.

Figure 59 diagrammatically shows a self-rotating grain.

Figure 60 diagrammatically shows rolling fiiction of a grain along the guide face.

Figure 61 diagrammatically shows sliding friction of a grain along the guide face.

Figure 62 diagrammatically shows the effect of the shape of the grain on the sliding friction along the guide face.

Figure 63 diagrammatically shows the effect of the shape of the grain on the sliding friction along the guide face.

Figure 64 diagrammatically shows the spiral bundle of paths which the stream of

material describes after it comes off the guide member.

Figure 65 diagrammatically shows the radius by which the impact face can be curved.

Figure 66 diagrammatically shows an impact face which is composed of a plurality of materials.

Figure 67a diagrammatically shows an impact face with cavities.

Figure 67b diagrammatically shows an impact face with grooves.

Figure 68 diagrammatically shows an impact member which is disposed in a frame structure.

Figure 69 diagrammatically shows a guide member which widens towards the outside.

Figure 70 diagrammatically shows the wear along the guide member in accordance with Figure 69.

Figure 71 diagrammatically shows the spiral path which the material describes bet- ween the guide member and the impact member.

Figure 72 diagrammatically shows the shift of the spiral path which the material describes between the guide member and the impact member.

Figure 73 diagrammatically shows a delivery end, the top end of which is directed obliquely backwards in the direction of rotation.

Figure 74 diagrammatically shows the shift of the spiral path as a result of wear in accordance with Figure 73.

Figure 75 diagrammatically shows the shift of the spiral path as the top end becomes progressively shorter.

Figure 76 diagrammatically shows a top view of a rotor which is equipped with hinged guide members.

Figure 77 diagrammatically shows a hinged guide member.

Figure 78 diagrammatically shows a top view of a rotor which is equipped with single subsequent guide members.

Figure 79 diagrammatically shows a top view of a rotor which is equipped with double subsequent guide members.

Figure 80 diagrammatically shows the wear along the guide face.

Figure 81 diagrammatically illustrates the wear pattern of a guide face which is of layered design.

Figure 82 diagrammatically shows a guide face with obliquely disposed layers.

Figure 83 diagrammatically shows a rotor in which the layered guide members are disposed at an oblique angle.

Figures 84a to c diagrammatically show the principle of integration.

Figure 85 diagrammatically shows an impact block with its axis in line with the spiral.

Figure 86 shows an impact block for which the axis has been corrected for the shift of the spiral path.

Figure 87 shows an integrated guide and impact member.

Figure 88 shows an integrated guide and impact member with a layered design.

Figure 89 shows a first rotationally symmetrical impact member.

Figure 90 shows a longitudinal section through the impact member of Figure 89.

Figure 91 shows a side view of the impact member of Figure 89.

Figure 92 shows a second rotationally symmetrical impact member.

Figure 93 shows a third rotationally symmetrical impact member.

Figure 94 diagrammatically shows the movement of the material during the impact.

Figure 95 diagrammatically shows a model for the calculation of the rebound behaviour of grains after they have struck the impact face of the rotating impact member.

Figure 96 diagrammatically shows a perspective view of part of the system.

Figure 97 diagrammatically shows a top view with a diagrammatic movement curve of the grains after they come off the rotating impact member.

Figure 98 diagrammatically shows a section on A-A of Figure 97.

Figure 99 diagrammatically shows a second top view with a diagrammatic movement curve of the grains after they come off the rotating impact member.

Figure 100 diagrammatically shows the parameters for designing a device according to the method of the invention.

Figure 101 diagrammatically shows a top view of the movements which the stream of material executes on a rotor with uniformly arranged rotating impact members.

Figure 102 diagrammatically shows a top view of the movements which the stream of material executes on a rotor with rotating impact members ananged in a differentiated manner.

Figure 103 diagrammatically shows the effect of the impact velocity on the grain size distribution of a broken product from a rotor with uniformly arranged rotating impact members.

Figure 104 diagrammatically shows the effect of the impact velocity on the grain size distribution of a broken product from a rotor with rotating impact members arranged in a differentiated manner.

Figure 105 diagrammatically shows the movement of the material along guide members which are arranged with the central feed at identical radial distances from the

axis of rotation.

Figure 106 diagrammatically shows the movement of the material along guide members which are arranged with the central feed at non-identical radial distances from the axis of rotation.

Figure 107 diagrammatically shows a cross-section on II-II of a first embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 108.

Figure 108 diagrammatically shows a longtitudinal section on I-I of a first embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 107.

Figure 109 diagrammatically shows a cross-section on IV-IV of a second embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 110.

Figure 110 diagrammatically shows a longtitudinal section on III-III of a second embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 109.

Figure 111 diagrammatically shows a cross-section on VI-VI of a third embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, and at the same time treating the grain shape of the broken product, in accordance with Figure 112.

Figure 112 diagrammatically shows a longtitudinal section on V-V of a third embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, and at the same time treating the grain shape of the broken product, in accordance with Figure 111.

Figure 113 diagrammatically shows a cross-section on VIII-VIII of a fourth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 114.

Figure 114 diagrammatically shows a longtitudinal section on VII-VII of a fourth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 113.

Figure 115 diagrammatically shows a cross-section on X-X of a fifth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 116.

Figure 116 diagrammatically shows a longitudinal section on IX-IX of a fifth embodiment, according to the method of the invention, for a device for breaking granular

material or processing it in some other way, in accordance with Figure 115.

Figure 117 diagrammatically shows a cross-section on XII-XII of a sixth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 118.

Figure 118 diagrammatically shows a longitudinal section XI-XI of a sixth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 117.

Figure 119 diagrammatically shows a cross-section on XIV-XIV of a seventh embodiment according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 120.

Figure 120 diagrammatically shows a longitudinal section on XIII-XIII of a seventh embodiment, in accordance with the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 119.

Figure 121 diagrammatically shows a cross-section on XVI-XVI of an eighth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 122.

Figure 122 diagrammatically shows a longitudinal section on XV-XV of an eighth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, of Figure 121.

Figure 123 diagrammatically shows the movement of the streams of material in a ninth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the collision means being formed by a part of the same material.

Figure 124 diagrammatically shows the said ninth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the collision means being formed by a part of the same material.

Figure 125 diagrammatically shows a tenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed essentially in accordance with the ninth embodiment.

Figure 126 diagrammatically shows a cross-section on XVIII-XVIII of an eleventh embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 127.

Figure 127 diagrammatically shows a longitudinal section on XVII-XVII of an eleventh embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 126.

Figure 128 diagrammatically shows a cross-section on XX-XX of a twelfth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 129.

Figure 129 diagrammatically shows a longitudinal section on XIX-XIX of a twelfth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 128.

Figure 130 diagrammatically shows a cross-section on XXII-XXII of a thirteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 131.

Figure 131 diagrammatically shows a longitudinal section on XXI-XXI of a thirteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 130.

Figure 132 diagrammatically shows a cross-section on XXIV-XXIV of a fourteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 133.

Figure 133 diagrammatically shows a longitudinal section on XXIII-XXIII of a fourteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 132.

Figure 134 diagrammatically shows a fifteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way.

Figure 135 diagrammatically shows a top view on XXVI-XXVI of a sixteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 136.

Figure 136 diagrammatically shows a longitudinal section on XXV-XXV of a sixteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 135.

Figure 137 diagrammatically shows a top view on XXVIII-XXVIII of a seventeenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 138.

Figure 138 diagrammatically shows a longitudinal section on XXVII-XXVII of a seventeenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 137.

Figure 139 diagrammatically shows a top view on XXX-XXX of an eighteenth embodiment, according to the method of the invention, for a device for breaking granular

material or processing it in some other way, in accordance with Figure 140.

Figure 140 diagrammatically shows a longitudinal section on XXIX-XXIX of an eighteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 139.

Figure 141 diagrammatically shows a top view on XXXII-XXXII of a nineteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 142.

Figure 142 diagrammatically shows a longitudinal section on XXXI-XXXI of a nineteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 141.

Figure 143 diagrammatically shows a top view on XXXIV-XXXIV of a twentieth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 144.

Figure 144 diagrammatically shows a longitudinal section on XXXIII-XXXIII of a twentieth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 143.

Figure 145 diagrammatically shows a cross-section on XXXVI-XXXVI of a twenty- first embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being equipped with two rotor blades, in accordance with Figure 146.

Figure 146 diagrammatically shows a longitudinal section on XXXV-XXXV of a twenty-first embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, in accordance with Figure 145.

Figure 147 diagrammatically shows a first arrangement of a rotating system in a crusher housing.

Figure 148 diagrammatically shows a second arrangement of a rotating system in a crusher housing.

DETAILLED DESCRIPTION OF THE INVENTION All the symbols used in the text are summarized on page 101.

Figure 1 shows in steps the progress of the method of the invention : the material is metered in a rotating system onto a rotor and, from there, is fed, optionally with the aid of

a preliminary guide member, to the central feed of a guide member rotating about a vertical axis of rotation (O), whereupon the material is brought up to speed along the guide face of the said guide member and, above all, is guided in the desired direction, so that the stream of material from the delivery end of the said guide member comes off from a predetermined take-off location (W) at a predetermined take-off angle (a) and at a take-off velocity (vab5) which is defined by the angular velocity (Q) and is thus predetermined, and is brought into an essentially deterministic spiral stream, when seen from a viewpoint which moves along, in an atmospheric environment at normal temperature or in an partially vaccum environ- ment at normal or lower temperatures, which spiral movement is synchronized with the movement of a rotating impact member, which is situated at a greater radial distance from the axis of rotation (O) than the said delivery end, in such a manner that the said stream of material strikes the impact face of the said rotating impact member at a predetermined hit location (T), at a predetermined impact angle and at an impact velocity (V, n, pac,) which can be selected with the aid of the angular velocity (Q) and is thus predetermined, whereupon, after the said stream of material has collided for the first time and comes off the said impact face, the stream of material is guided at the residual velocity, which is at least as great as the impact velocity (Vjnlpact) in a straight stream (R), when seen from a stationary viewpoint, and the stream of material, immediately after the first impact and at an essentially predetermined collision velocity (V, at an essentially predetermined collision angle, strikes the collision face of a stationary impact member which is disposed in the said straight stream (R), which collision face may consist of a metal face or is formed by a bed of the same material. A number of specific additional possibilities are indicated, as are a number of factors which affect the separate steps in the process.

In all the embodiments described, it is possible not to meter part of the material onto the rotor blade, but rather to guide it in a vertical stream (Rv) around the outside of the rotating system, across the front of the collision face, where it is hit by the material which is flung out of the system from the impact face, after which the two material streams strike the collision face.

Figure 2 diagrammatically illustrates, for the resistance-free state, the movement which the grain executes in the rotating system, when seen from a stationary viewpoint. On the rotor (2), the grain, since it makes only limited contact with the metering face (3), which in this case is rotating, moves in a virtually radial stream (R) in the direction of the edge (26) of the metering face (3), where the grain is taken up by the central feed (9) of the guide member (8), and is guided in a spiral (logarithmic) movement (R) along the guide face (10), the grain being accelerated and moved in the desired direction, whereupon the grain

is moved in a straight stream (R) from the delivery end (11) of the guide member (8), at a take-off velocity (v. At the moment at which the grain comes off the guide member (8), a transverse velocity component (v,) and a radial velocity component (v) are active, the radial velocity component (vr) being decisive for the direction of the movement ; i. e. it is decisive for the take-off angle (a). The grain moves further, when seen from a stationary viewpoint, at a constant velocity (vab5) along the said straight stream (R), in the direction of the rotating impact member (14).

Figure 3 diagrammatically illustrates, for the resistance-free state, the relative movement of the grain, when seen from a viewpoint which moves along. As can be seen, the grain on the metering face (3) moves in a spiral stream (Sr), which approximates to the Archimedes'spiral, towards the edge (26) of the metering face (3), where it is taken up by the central feed (9) of the guide member (8) and is accelerated and directed along the guide face (10), in this case in the radial direction (Sc), whereupon the grain is moved from the delivery end (11) in a spiral stream (S), which, at the moment the material moves of the delivery end (11), is a continuation of the stream (Sc) which the grain describes along the guide member (8), along which spiral stream (S) the grain is guided towards the rotating impact member (14) in a direction which is essentially opposite to that of the straight stream (R), the direction of the spiral stream (S) being determined essentially by the radial velocity component (vu).

As shown in Figure 4, the grain, when seen from a viewpoint which moves along, describes on the metering face (3) as it were a"short"spiral (S), which, with the aid of the guide member (8), is converted into a"long"spiral (S), the"length"of this spiral, as is shown, being determined by the radial velocity component (v). As the length of the guide member (8) increases (a->b), the take-off angle (raz increases and the grain is moved in a"longer"spiral (S) (A-4B).

In order to understand the method of the invention correctly, it of essential import that the movement (R) (S) which the grain describes in the rotating system, thus from the metering face (3), along the guide member (8) to the rotating impact member (14), is simultaneously seen from both a stationary viewpoint and from a viewpoint which moves along.

Figure 5 shows these movements, when seen from both the stationary (I) and the moving (II) position. While the grain moves at a constant velocity (vab5) along the straight stream (R), the relative velocity (Vre,) of the movement along the spiral stream (5) increases as the grain moves further away from the axis of rotation (O). At the moment at which the grain comes off the guide member (8), it has a relative velocity (Vre,') which is lower than the absolute velocity (vau5). Along the spiral stream (S), the absolute velocity is quickly

exceeded by the relative velocity (Vre,"), after which, further on in the spiral stream (S), velocities (Vre,"') can be reached which are a multiple of the absolute velocity (vau5).

In the method of the invention, use is made of this high relative velocity (Vre,"') by allowing the grain to strike, at this relatively great impact velocity (Vhupact) the impact face (15) of an impact member (14) which rotates together with the system. In this way, the method of the invention makes it possible to allow a grain, which comes off the guide member (8) at a relatively low velocity (vab5) (Vre,'), to impact at a very high relative velocity (Vimpac). This means that the wear to the guide member is reduced considerably and the impact, if the impact face (15) is disposed correctly, takes place at an optimum, virtually perpendicular impact angle (p), with the result that a great comminution intensity is obtained, while the wear even to the impact face (15) is limited, since impact wear is much lower than guide wear.

A particular advantage according to the method of the invention is that the grain, after the first impact, comes off the impact face (15) at a residual velocity (V,), which is at least as great as the impact velocity (V ), at which residual velocity (Vresidual) the grain is moved into a straight stream (R), when seen from a stationary viewpoint, whereupon the grain, immediately after the first impact, can strike for a second time, at a high collision velocity (Vcollision), a stationary impact member (16), which impact can likewise take place at an optimum, virtually perpendicular angle.

It has been demonstrated that an impact at an angle of 80 to 85° for most types of material results in a much higher breaking probability than a perpendicular impact. The breaking probability can be increased considerably still further by allowing the grain to impact twice immediately in succession.

The method of the invention thus makes it possible, with a relatively lower power consumption and a relatively low level of wear, to allow the grains to impact at an opti- mum angle, at least twice immediately in succession, with the result that a high breaking probability is achieved.

Furthermore, the method of the invention makes it possible to synchronize the movement of the grain with the movement of the rotating impact member.

Figure 6 shows the spiral stream (S) which the grains describe between the guide member (8) and the rotating impact member (14). As indicated previously, it can be demonstrated that if the take-off location (W) and the take-off angle (a) are not affected by the angular velocity (Q), and the take-off velocity (vars) is proportional to the angular velocity (#), the route covered as the grain describes the spiral stream (S) and the route covered (C#) as the rotating impact member (14) describes the periphery (27) which is

described by the rotating impact member (14), are independent of the angular velocity (Q). The instantaneous angle (0), which is formed by the radial line (48) on which is situated the location (W) where the grains leave the guide member (8) and the radial line (49) on which is situated the location (T) at which the grains hit the rotating impact member (14), is thus not affected by the angular velocity ().

This makes it possible to synchronize the movement which the rotating impact member executes with the movement which the grain executes, so that, irrespective of the angular velocity (Q), the impact of the grain against the impact face of the rotating impact member takes place at a predetermined synchronization location (T) and at a predetermined impact angle (p), the impact velocity (V iiiipact) being proportional to the angular velocity (Q) and can thus be selected with the aid of the said angular velocity (Q) without in so doing affecting the impact location (T) or the impact angle (p).

However, a synchronization of this kind is only possible if the individual grains from the stream of material are guided, from the rotating impact member (14) in an essentially deterministic spiral stream (S), i. e. from a defined take-off location (W) and at a defined take-off angle (a), which is not affected by the angular velocity (Q). This places particular demands on the guide member (8).

Figure 7 and Figure 8 diagrammatically show a first possibility of how, according to the method of the invention for making material collide in a rotating system, a stream of material can be moved from a rotating guide member (8) into a spiral path (S), when seen from a viewpoint which moves together with the said guide member (8), and then strikes the impact face (15) of a freely suspended rotating impact member (14) which rotates in the same direction, at the same angular velocity and about the same axis of rotation (O) as the said guide member (8), and the movement of which is synchronized with the movement of the said stream of material (S). After the material has struck the impact face (15), when it comes off the rotating impact face (15), it is guided further in a straight path (Rr), when seen from a stationary viewpoint, after which the material strikes the hard metal collision face (46) of a stationary impact member (16) which is disposed in this straight path (Rr) ; in this case, the collision face may also be formed by an autogenous bed (47) of the same material.

It is possible here to equip the rotating system with at least two guide members and associated rotating impact members, in which case the radial distances from the axis of rotation to the star of the guide member do not have to be made equal for all the guide members, the corresponding radial distances to the end of the guide members do not have to be made equal for all the guide members, and the corresponding radial distances to the

rotating impact members do not have to be made equal for all the impact members. An arrangement of this kind makes it possible to vary the amounts of material which are taken up by the guide members and to allow the respective streams of material to strike the impact members at different velocities. This will be dealt with in detail further on in the text.

The method of the invention also makes it possible to classify and sort a stream of granular material (Sr), when it comes off the rotating impact face, optionally in combination with breaking this granular material.

Figure 9 diagrammatically shows how the broken fragments, which are formed when a grain breaks during the impact against a rotating impact member (14), behave. It is known that on impact loading the broken fragments which are formed can be subdivided into three fractions, namely coarse (508), intermediate (509) and fine (510), the quantities of the respective fractions shifting towards fine as the impulse loading increases. After impact, the coarse broken fragments (508) generally rebound at a greater angle than the finer broken fragments (510), thus resulting, as it were, in a fan of rebounding broken fragments, with the coarse fragments (508) in the top of the fan, the intermediate fragments (509) in the middle of the fan, and the fine fragments (510) in the bottom of the fan ; the fine fragments are frequently flung outwards along the impact face (15) (i. e. they slide down the latter). By disposing a separating plate (427) in the fan, the fine broken fragments (510) can be roughly separated from the coarse broken fragments (508). By making the separating plate (427) vertically adjustable, the division can be controlled. The wear can be limited by allowing the separating plate (427) to rotate together with the rotor. This also makes it possible to separate softer constituents of the stream of grains, which softer constituents break at a specific impact velocity, from hard grains which do not break at the said impact velocity.

Figure 10 diagrammatically shows how it is possible to use a (vertically adjustable) separating plate (427) of this kind to separate granular material with a greater elasticity (511), which has a greater rebound angle, (from grains with a lower elasticity (512), which have a smaller rebound angle.

Figure 11 diagrammatically shows a first possibility according to the method of the invention for making material collide, the first possibility being equipped with a separating member (427), which is vertically adjustable and with which it is possible to classify or sort material.

Figure 12 and Figure 13 diagrammatically show a second possibility, according to the method of the invention, for making material collide, the material being guided along

two guide members (8) (8') situated directly above one another, along two essentially identical spiral streams (S) (S') situated directly above one another, in the direction of one rotating impact member (14') associated with these two guide members.

Figure 14 diagrammatically shows a third possibility, according to the method of the invention, for making material collide, the material, after it comes off the impact face of the rotating impact member (428) of the first system (429), striking a stationary impact member (530), after which the material is guided to the metering face (430) of a second system (431), which is situated beneath the first system (429), which second system (431) rotates in the same direction, at the same angular velocity and about the same axis of rotation (O) as the said first system (429) ; in which case the radial distances from the axis of rotation (O) to respectively the guide member (428) (432) and the rotating impact member for the two systems (429) (431) may differ.

Figure 15 and Figure 16 diagrammatically show a fourth possibility, according to the method of the invention, for making material collide, the stream of material, after it comes off the impact face (14) of the rotating impact member of the first system (433), striking the impact face (434) of a second system (435), which is situated beneath the first, which second system (435) rotates about the same diagonal as the first system (433), but in the opposite direction.

Figure 17 and Figure 18 diagrammatically show a fifth possibility, according to the method of the invention, for making material collide, the stream of material being uniformly distributed over two systems (436) (437) situated one above the other which rotate, optionally at the same angular velocity, in opposite directions about the same axis of rotation, the guide members (438) (439) and the impact members (440) (441) of the respective systems (436) (437) forming mirror images of one another. The method of the invention makes it possible, by disposing the impact faces (442) (443) of the respective systems (436) (437) at an angle, to guide both the streams of material (RC) (Rc'), when they come off the respective impact faces (442) (443), in a direction obliquely outwards, when seen from the axis of rotation, obliquely forwards, when seen in the direction of rotation, and obliquely outwards, when seen from the plane of the rotation, in the direction of the plane of rotation of the other (opposite) system. The respective straight streams (R) Rc') then cross one another at a location (444) which is at a greater radial distance from the axis of rotation than the respective rotating impact members (440) (441), at a level between the two systems. If the angular velocity (Q) at which the respective systems rotate is equal, the paths (RC) (R cross one another on the radial line, when seen from the horizontal plane, on which are situated the respective rotating impact members (440) (441) at the moment at which they

cross one another.

Figure 19 diagrammatically shows a sixth possibility, according to the method of the invention, for making material collide, the collision means not being formed by an impact member, but by a second part of the material. In this case, the streams of material are flung outwards to two different radial distances from the respective guide members, the movements of the respective streams of material being synchronized in such a way that the streams of material cross one another at a location at a radial distance from the axis of rotation which is greater than the corresponding radial distance to that guide member which is situated furthest away from the axis of rotation.

Figure 20 diagrammatically depicts a radially designed guide member (29), and Figure 21 depicts a bent guide member (50), each guide member (29) (50) being equipped with a central feed (67) (70), by means of which the material is taken up from the metering face (3), which merges into a guide face (68) (71), along which the material is brought up to speed and is guided primarily in the desired direction, which guide face merges into a delivery end (69) (72), by means of which the material is guided in a spiral stream (S) in an essentially deterministic manner.

Figure 22 diagrammatically shows the movement of a stream of material (S) on a rotating face of a rotor (2), when seen from a viewpoint which moves together with the said rotor (2). The said stream (Sr) is guided outwards in a spiral movement, which approximates to an Archimedes'spiral, and is taken up by the central feed (9) of a guide member (8), which in this case is arranged radially, and is therefore directed virtually transversely to the spiral stream (Sr). With the aid of the said central feed (9), the spiral stream of material (S) is converted into a radial movement (Sc) and is guided towards the guide face (10).

Figure 23 provides a diagrammatic depiction of the central feed. The length of the central feed (9) is given here by ((c) which length is essentially determined by the width (Sb) of the spiral stream (Sr) at that location. The conversion of the spiral stream (Sr) into a straight radial movement (Sc) takes place along this central feed (9), it being necessary to take into account the fact that the length which is required in order to allow the stream of material to make good contact with the guide face (10) may be slightly longer than the given length (toc) of the central feed (9). The actual guide begins from this region (74).

Figure 24 shows the Archimedes'spiral (73). On the basis of a movement in an Archimedes'spiral (73), the radial width of the spiral is 27ta, a being calculated as : a = Va/ Q, i. e. the initial radial velocity (Va) which the stream of material has at that location, divided by the angular velocity (Q).

Figure 25 indicates how it is possible to calculate the minimum length (#c) which the central feed (9) has to have in order to take up the stream of material, specifically as the maximum distance which is given by the angle (%) which a grain, in the region in front of the said central feed (9), when seen in the direction of rotation, can cover in the radial direction starting from the periphery (ra) which the start point (76) of the central feed (9) describes, before the grain is taken up by the said central feed (9). In the process, the grain moves naturally in a spiral stream (77), when seen from a viewpoint which moves along.

The radial distance, or width of the spiral stream (Sc) which the said grain now covers is a function of the rotational speed (rpm), of the initial radial velocity (Va) which the grain has at the moment at which it passes into the region (75) before the said central feed (9), and the angle (x) between the radial line on which is situated the location (78) where the grain hits the guide member (8) and the radial line on which is situated the location of the start point (79) of the following central feed arranged in the direction of rotation ; which length () of which central feed (9) essentially satisfies the equation : <BR> <BR> <BR> <BR> <BR> = XVa<BR> <BR> <BR> <='D Figures 26 and 27 diagrammatically show how the angular velocity (Q) affects the spiral stream (Sr) on the rotor (2), and thus the length ((c) of the central feed (9). Figure 26 shows, for a low rotational speed (rpm), that the material moves in a relatively wide spiral stream (Sr) over the rotor (2), with the consequence that the length () of the central feed (9) is relatively great. Allowing the rotor (2) to rotate at a greater speed (rpm) means, as is shown diagrammatically in Figure 27, that the spiral stream (Sr) becomes less wide, leading to a shorter length (t"c) of the central feed (9).

It is furthermore apparent that the initial radial velocity (Va) which the stream of grains has at the moment at which it comes into contact with the central feed (9) has a considerable effect on the width (Sb) of the spiral stream (Sr). For example, for an angle X = 90 (approximately four guide members) and an initial radial velocity (Va) of 2 m/sec, the minimum length of the central feed (#c), for a rotational speed of 100 rpm, is in abso- lute units ec = 600 and, for a rotational speed of 1000 rpm, c = 60. If the initial radial velocity (V) is 5 m/sec, the respective values are ec = 1500 (at 100 rpm) and fc = 150 (at 1000 rpm). The length (6c) of the central feed decreases with the number of guides, i. e. the angle (x).

It is preferred to keep the length (8c) of the central feed (9) as short as possible, so that

the stream of material (Sr) can make contact as quickly as possible with the guide face (10) and can be guided from the delivery end (11) in the desired spiral movement (S) at as low a velocity (Va) as possible, i. e. at as short a radial distance (rl) as possible. As indicated, it is possible to make do with a shorter length (for) as the angular velocity (rpm) is increased and the rotor (2) is designed with more guide members (8). However, the maximum number of guides is limited by the necessary free feed of the stream of material (S) to the central feed (9). Flow rate and grain dimension play an important role in this connection. If the distance (%) between the guide members (8) is made too short, this impedes the feed of the stream of material (S) to the said central feed (8), with the consequence that the material accumulates on the metering face (3). With regard to the grain dimension, it can be stated as a general rule that the calculated length (l of the central feed (9) has to be at least twice as great as the maximum grain dimension of the grains from the stream of material (Sr).

The initial radial velocity (V) can be limited by limiting as far as possible the height of drop of the material during metering onto the rotor (2), and by limiting the diameter of the rotorblade ; however, also depending on the maximum grain dimension, a certain mini- mum diameter of the rotorblade is required.

Figure 28 shows how it is possible to limit the radiale velocity (Va) by suspending a partition (80) in the feed tube (81) above the metering face (3) of the rotor (2). However, here too it is necessary to take into account the fact that, in order to achieve a defined capacity, a defined flow rate is necessary during the metering.

To bridge the relatively short distance between the guide member (8) and the rotating impact member (14) without the grain being significantly affected by air resistance, any air movements and the force of gravity, a take-off velocity (vab5) of approximately 10 m/ sec is normally sufficient. Furthermore, in order to move the said material into a spiral stream (S) in an essentially deterministic manner, it is of essential importance that the take- off angle (a) of the individual grains from the stream of grains is virtually constant and that all the grains come off the guide member (8) at virtually the same take-off location (W).

For the method of the invention, the function of the guide member (8), in addition to providing a certain acceleration, is therefore primarily to direct the movement of the grains along the guide face (10) in such a manner that the stream of material comes off the guide member (8) at virtually the same take-off location (W), at a virtually constant take-off angle (a) and at virtually constant take-off velocity (vars). To this end, the grains from the stream of material, after they have been taken up by the central feed (9), must quickly and correctly make contact with the guide face (10).

As is diagrammatically indicated in Figure 29, the radial length () of the guide member (8) is essentially the determining factor here. An excessively short guide member (8) with a length (e"') which is shorter than the required length (8c) of the central feed (9) (situation D), the radial length (e"') of the guide member (8) thus being shorter than the width of the spiral stream (Sr), is the factor which causes only some of the grains from the stream of material (Sr) to come into contact with the central feed (9). A substantial proportion of the grains moves past the front of the said central feed (9) (as it were rolls off the rotor (2)) and is not taken up by the said central feed (9). The grains which, owing to the lack of a guide face, are not guided therefore leave the"guide member"in a chaotic manner, with the take-off angle (a) varying (α"') from virtually tangential to virtually radial, while the take- off velocity (v"'bs) varies from nothing to the tip velocity (Vtjp) at that location. It is impossible to synchronize a stream (S"') of this kind effectively with the movement of a rotating impact member (14). As the length of the guide member (8) increases (situations C and B), thus involving a guide member (8) with a central feed (9) and a guide face (10), the grain can make better contact with the guide face (10), and the spread of the take-off velocity (V"abs-4 v'a) and the spread of the take-off angle (α"#α') decrease, resulting in a process which proceeds in a more deterministic manner. If the length () of the guide member (8) is made large enough to produce a guide face (10) with sufficient contact length (situation A), the separate grains from the stream (Sr) make contact with the said guide face (10) in such a manner that the grains all leave the guide member (8) from virtually the same take-off location (W), at virtually the same take-off angle (a) and at a virtually constant take-off velocity (v,, b,) which is determined by the angular velocity (f2), and are guided in an essentially deterministic spiral stream (S).

Directing the stream of material along the guide face (10) is done essentially by means of the radial velocity component (vr) ; for a correct direction, it is therefore necessary for the stream of material to develop a specific minimum radial velocity component (vr) along the guide face (10). To launch the grains from the guide member (8) in an essentially deterministic manner, it is necessary for a radial velocity component (vr) which is approximately 35-55% of the transverse velocity component (v,) to be developed along the guide face (10), thus resulting in a take-off angle (a) of approximately 20 to 30°. It can therefore be stated that the stream of material (SroSc) can be brought into a spiral stream (S) in an essentially deterministic manner, with the aid of a guide member (8), if the take- off angle (a) is greater than 20°, and preferably greater than 30°.

For this purpose, the guide member (8) must be equipped with a central feed (9) which has a length (#c) to take up the stream of material (Sc) and a guide face (10) which

has sufficient guidance length ((g) to direct the stream (S). These factors together determine the length () of the guide member (8).

Figure 30 shows how this guidance length (eg) can be calculated as a function of the take-off angle (a). The guidance length (eg) is given here as the difference between the radial length (ro) from the axis of rotation (O) to the start point (83) of the guide face (10) (end point of said central feed) and the corresponding radial length (rl) to the end point (84) of the said guide member (8) (end point of said delivery end), i. e. : eg = rl-rc The length (eg) of the guide member (8) can thus be calculated on the basis of the relationship (r/rl). For radially arranged guides and for the resistance-free state, this relationship essentially satisfies the equation : Figure 31 shows a guide member (8) which is not arranged radially, with the result that the relationship (rC/rl) changes and, as a function of the take-off angle (a), can essentially be given by the equation : Cos OC rl2-r2 a = arctan rl-sin ap r12-r2 Figure 32 shows the connection between the take-off angle (a) and the relationship (rgrl) for guide members which are arranged radially (85) and non-radially (86). The degree to which the non-radial guide members (86) differ from the radial guide member (85) is shown by the angle (K) between the radial line on which is situated the end of the radial guide member (85) and the radial line on which is situated the end of the non-radial guide member (86), a non-radial guide member (86) which is situated towards the front, in the direction of rotation, by comparison with the radially arranged guide member (85) forming an angle (+K), and a non-radial guide member (86) which is situated towards the rear forming an angle (-K). Furthermore, it is necessary to take into account the friction of the stream of material (R) along the guide face (10).

Figure 33 diagrammatically illustrates how friction affects the take-off angle (a) ; the take-off angle (a) becomes smaller as the influence of the friction, which can be given by the coefficient of friction (co), increases. The coefficient of friction (m) is determined by

the contact between the grains and the guide member (8), the friction furthermore being influenced by the shape of the guide member (8).

However, it is extremely complicated to include the coefficient of friction (co) in the equation ; if a curved guide member is used, this is essentially impossible. The friction increases if the guide member (8) is disposed towards the front in the direction of rotation, and reduces if it is disposed towards the rear. However, the situation can be simulated fairly accurately with the aid of a computer. In any case, the guide length () of the guide face (10), which is required in order to launch the stream of material (Rc) in an essentially deterministic manner, increases together with the coefficient of friction (Q).

On the basis of the above description, it can be stated in a general sense for the method of the invention that, in order to realize an essentially deterministic take-off process of the grains from the guide member (8), or so that the grains leave the guide member (8) at a take-off angle (a) of at least 30°, the length () of the guide face (10), or the radial distance (ro) from the axis of rotation (O) to the end point of the guide member (8), must be 331/3 % greater than the corresponding radial distance (r,) or (rO) to the start point (84) of the guide member (8).

Figure 34 diagrammatically shows a rotor blade, the granular material being taken up, from the natural spiral movement (S) which it describes on the metering face (472), by the central feeds of straight guide faces, which in this case are respectively disposed radially (473) (K=0°), towards the rear in the direction of rotation (474) (+K) and towards the front in the direction of rotation (475) (-K). The angle (K) at which the guide members are disposed affects the direction of the spiral path (S) in which the material is guided from the delivery end.

Figure 35 diagrammatically shows the situation in the event that the guide face (474) is disposed directed towards the rear (+K) in the direction of rotational and Figure 37 shows the situation in the event that the guide face (475) is disposed directed towards the front (-K) in the direction of rotation. In all cases, the grain is moved in the relative spiral motion (S) in the direction which is in line with the movement (S d) which the grain describes along the guide face (473) (474) (475), the relative velocity (V'rel) in all cases being equal to : -in the event that the guide face (475) is directed towards the rear (+K), the friction (o), and hence the wear along the guide face (475), increases, the take-off angle (a) decreases and the absolute take-off velocity (vabS) increases ; -in the event that the guide face (474) is directed towards the front (-K), the friction (cl)), and hence the wear along the guide face, decreases, the take-off angle (a) increases,

while the absolute take-off velocity (Va,., For the method of the invention, i. e. guiding a grain at a take-off velocity (Vabs) which is as low as possible and at a take-off angle (a) which is as great as possible from the guide member in a deterministic spiral path, a guide face (474) which is disposed directed towards the rear (+K), is therefore preferred ; in this case, moreover, the wear is limited.

Figure 36 diagrammatically shows a grain at the instant at which it comes off the delivery end, for a radially disposed guide face (473).

Figure 38 shows a guide member (87) which has a type of S-shape and is disposed with the guide faces respectively directed radially (475) (K=0), towards the front (477) (-K) and towards the rear (476) (+K). A guide face (476) (+K) which is directed more towards the rear (+K) is normally preferred here.

The central feed (88), which is designed curved forwards in the direction of rotation, as far as possible lies in line with the natural spiral stream (Sr) which the material describes on the rotor (2), which central feed (88) merges into a guide face (89) which is of straight design, is directed towards the rear in the direction of rotation and merges into a delivery end (90) which is curved towards the rear in the direction of rotation, which delivery end (90) is curved at least in such a manner that the curvature is in line with the spiral stream (S) which the said material describes when it comes off the said delivery end (90).

The specific curved shape of the central feed (88) makes it possible to take up and guide to the guide face (89) the stream of material (Sr) better, in a flowing movement from the rotor (2). Since the guide face (89) is directed towards the rear, the acceleration is limited, while the material is guided from the curved delivery end (90), as it were in a natural manner, in the intended spiral stream (S), towards the rotating impact member (14). This design makes it possible to allow the stream of material (S) to come off the guide member (87) at a relatively low velocity (Vabs) in an essentially deterministic manner.

In the process, both the energy consumption and the wear are limited, while the stream of material (S-S) comes off the S-shaped guide member (87) at a lower take-off velocity (vars), and thus is able to develop a greater relative velocity (Vre,) along the spiral stream (S), and hence hits the rotating impact member (14) at a greater velocity (Vin, pact).

Figure 39 diagrammatically shows in detail the S-shaped guide face (476) which is directed towards the rear (+K). In this case, the central feed (478) is as far as possible disposed in line with the spiral movement (Sc) which the material describes on the metering face (479) and, from there, is curved towards the rear (+K) in the direction of rotation. The central feed (478) merges into a straight guide face (479), which is directed towards the rear (+K) in the direction of rotation and in turn merges into a delivery end (480) which is

curved towards the rear (+K) in the direction of rotation.

Figure 40 diagrammatically shows the movement of the stream of grains, respectively the short spiral movement (Sc) on the metering face, the movement (S) along the central feed (478), the guide face (479) and the delivery end (480), the way in which the grain comes off the delivery end (480) and the long spiral movement (S) in which the stream of material is then guided. It is normally preferred, in order for a guide member (476) of this kind to function optimally, for the central feed (478), the guide face (479) and the delivery end (480) to have an approximately equal radial length, i. e. (central feed), tg (guide face) (delivery end). The movement of the granular material along the guide member (476) is determined by the centrifugal force, which is directed from the axis of rotation (O), and the Coriolis force which is directed perpendicular to the plane of guidance. Under the influence of these forces, the normal force (N) which the grain exerts on the guide face increases, and hence so does the friction force (W). If a delivery end (480) is designed such that it is curved towards the rear (+K) in the direction of rotation, this leads to the increase in the normal force (N) being curbed. The normal force (N) is reduced gradually by casing the delivery end (480) round. At the instant at which the normal force N = 0, the stream of material (Sd) comes off the delivery end (480) and is moved into the desired, deterministic spiral movement (S) in a manner which is as far as possible"natural"and with a relative velocity (V're,) which is as low as possible and with as little wear as possible to the guide member (476).

Figure 41 shows a number of embodiments for the respective situations : -the central feed (481) is directed radially straight (482) or, in the direction of rotation, straight towards the rear (483) or curved towards the front (484) or towards the rear (485) ; -the guide face (486) is directed radially straight (487) or, in the direction of rotation, straight towards the rear (488) or curved towards the rear (489) ; -the delivery end (490) is directed radially straight (491) or, in the direction of rotation, straight towards the rear (492) or curved towards the rear (493).

The guide member (494) can in this way be designed and disposed as a combined unit. The specific arrangement is determined here by factors which were explained above.

Figure 42 diagrammatically shows an arrangement in which the central feed (495) is disposed separately : when seen in the direction of rotation, in front of the guide face (496) and the delivery end (497). An arrangement of this kind offers the possibility of replacing the central feed (495), the bend (498) of which is subject to high friction forces and hence wear, separately, in which case it is preferred for the thickness of both the central feed (499) and the guide face with delivery end (500) to increase progressively outwards.

Figure 43 shows a preliminary guide member (4), the central inlet (5) of which lies directly behind the central feed (9), when seen in the direction of rotation, which preliminary guide member (4) extends, from the said central inlet (5), with the preliminary guide face (6) in a direction which is essentially opposite to the direction of rotation, towards a delivery location (7) which is directed towards the central feed (9) of a subsequent guide member (8). A preliminary guide member (4) of this kind makes it possible to feed the spiral stream (S) better to the central feed (9) of the guide member (8), without impeding the movement of the grain on the rotor (2), and also to prevent grains from being able to fly off or simply roll off the metering face, thus not being taken up by the central feed (9) or coming into contact with the guide member (8) at a greater radial distance from the axis of rotation (O), thus substantially impairing the guidance process.

Figures 44 and 45 diagrammatically show, for the resistance-free state, the movements of the material between the location (W) where this material leaves the radial guide member (8) and the location (T) where the material strikes the rotating impact member (14), when seen respectively from a stationary viewpoint (Figure 44) and a viewpoint which moves together with the system (Figure 45).

In reality, the movement of the material is actually subject to, inter alia, friction with components of the rotor and to air resistance. The same also applies to the force of gravity.

These factors affect the stream, although without significantly changing the nature of the movement. The grain size and the grain configuration play an important role here. In the following observations, these effects are, for the time being, discounted.

When seen from a stationary viewpoint (Figure 44), when the material comes off the guide member (8) at a radial distance (ro) from the axis of rotation (O), at a take-off velocity (va,, a radial velocity component (vr) and a velocity component which is perpendicular to the radial component, i. e. a transverse velocity component (v,), are active. The transverse velocity (vt) of the material at the moment at which it leaves the guide member (8) corresponds to the tip velocity, i. e. the velocity at the location of the discharge end (11), of the guide member (8) : tip velocity = Qrl. If the radial (vr) and transverse (v,) velocity components are equal, the material leaves the guide member (8) at an angle (a) of 45°. In reality, the magnitudes of the velocity components may differ, with the result that the direction of movement changes : the transverse velocity component (v,) is normally greater than the radial velocity component (vu), but the reverse may also be true. The take-off angle (a) can thus be greater than and less than 45°, but is normally less than 45°. As indicated above, it is necessary, in order to bring the said material into an essentially deterministic stream, for the take-off angle (a) to be greater than 20°, and preferably

greater than 30°.

Since the straight movement path (R) is not directed from the axis of rotation (O), but rather from a location (W) situated at a radial distance from the axis of rotation (O), there is a shift outwards, when seen from the axis of rotation (O), at a radial distance which is greater than the radial distance to the location (W) where the material leaves the guide member (8), between the radial (vr) and transverse (v,) velocity components, when seen from a stationary viewpoint, the magnitude of the radial component (vr) increasing and that of the transverse component (v,) decreasing.

When seen from a viewpoint which moves together with the guide member (8) (Figure 45), the situation is different. After coming off the guide member (8), the grain moves at a relative velocity (Vre,) along the spiral stream (S), the direction of which is opposite to that of the straight stream (R), the relative velocity (Vre,) increasing as the grain moves further away from the axis of rotation (O). At the moment at which the grain comes off the guide member (8), there is no relative transverse velocity (V,'re,) active. At that moment, the relative movement is determined only by the radial velocity component (v).

When the material comes off the guide member (8), a relative transverse velocity compo- nent (v,) begins to develop. In the process, as the material moves further away from the axis of rotation (O), the radial velocity component (vr) increases considerably, and the transverse velocity component (v,) increases very considerably. The material therefore describes a spiral stream.

In this case, for both the movement in the straight stream and in the spiral stream (S), i. e. when seen from both the stationary and the moving viewpoint, the radial velocity component is, at any distance from the axis of rotation (O), identical (V. = vr), and increases as the grains move further away from the axis of rotation (O). Since, as the radial distance between the location (W) where the material leaves the guide member (8) and the location (T) where the material hits the rotating impact member (14) increases, the transverse velocity component (v,) increases more than the radial velocity component (Vr), the direction of movement of the relative velocity (Vre,), further on in the spiral stream (S), increasingly comes to lie as a continuation of the direction of movement, which is in fact in the opposite direction, of the rotating impact member (14), with the result that the impact intensity increases when the grain hits the rotating impact member (14). However, the spiral movement (S) described by the material prevents the relative movement (S) of the grain and the movement (B) of the rotating impact member (14) from being able to lie completely in a single line. Moreover, the distance (r-rl) between the location (W) where the material leaves the guide member (8) and the location (T) where it strikes the rotating impact

member (14) is also limited for practical reasons.

The spiral movement (S) which the material describes according to the method of the invention can, as shown in Figure 46, be given, when seen from a co-rotating position, as the connection between the instantaneous angle (8), the associated radius (r) and a factor f, and essentially satisfies the equation : ° = arctanß P cos a | _ p cos ot tpsina cos a cos a 6 = arctan pMna+r f which instantaneous angle (0) is defined as the angle between the radial line (48) on which is situated the location (W) where the stream of material (S) leaves the guide member (8) and the radial line (49) on which is situated the location (T) where the stream of material (S) hits the rotating impact member (14). The equation shows that the spiral stream (S) which the said material describes after leaving the guide member (8), when seen from a viewpoint which moves together with the rotating impact member (14), is determined entirely by the location (W), i. e. the radial distance (rl), from where the material leaves the guide member (8), by the take-off angle (a) of the material from the guide member (8) and by the relationship between the transverse component (v,) of the absolute velocity (va"5) on leaving the guide member (8) and the tip velocity (V, ip) of the delivery end (11) of the guide member (8), i. e. the factor f. It is extremely important that the stream (S) should not be affected by the angular velocity () ; as pointed out earlier, this essentially forms the basis of the method of the invention.

The fact that the instantaneous angle (0), which has an unambiguous connection with the radial distance (r) of the axis of rotation (O) to the hit point (T), can be calculated makes it possible to position the rotating impact member (14) accurately with respect to the guide member (8).

Figure 47 shows how a grain, after it has struck the rotating impact member for the first time, after coming off the impact face, can be guided in a second spiral path, when seen from a viewpoint which moves together with the impact member, and can strike a second rotating impact face which is disposed in the said second spiral path. In this way, the material in the rotating system is brought to speed in two steps. After the material comes off the said impact face of the said second rotating impact member, the material is guided in a straight path, when seen from a stationary viewpoint. In the process, the material is moved in a first spiral path (S') from the delivery end (11), when seen from a viewpoint which rotates together with the guide member (8), in a direction towards the rear, when

seen from the direction of rotation, after which the material strikes the impact face of a first impact member (14'), the angle (0') between the radial line on which is situated the location (11) where the said as yet uncollided material leaves the said guide member (8) and the radial line on which is situated the location where the path (S') of the said as yet uncollided material and the path (C') of the said first impact member (14') intersect one another being selected in such a manner that the arrival of the said as yet uncollided material at the location where the said paths (S') (C') intersect one another is synchronized with the arrival at the same location of the said first impact member (14) ; after this, the material, when it comes off the said first impact member (14), is moved into a second spiral path (S") and strikes the second impact member (14"), the angle (0") between the radial line on which is situated the location where the said as yet uncollided material leaves the said guide member (14) and the radial line on which is situated the location where the path (S") of the said material which has collided once and the path (C") of the said second (14") impact member intersect one another being selected in such a manner that the arrival of the said material which has collided once at the location where the said paths (S") (C") intersect one another is synchronized with the arrival at that location of the said second impact member (14") ; after this, the material, after it comes off the said second impact member (14") is moved into a straight path (R) when seen from a stationary viewpoint which straight path (R) is directed towards the front, when seen from the direction of rotation, after which the material strikes a stationary impact member (16) which is designed in the form of an impact segment or a bed of the same material.

The velocity (Vhnpac,) at which the material, with the aid of the rotating impact member (14), hits the impact face (13) increases considerably, as has been stated, as the difference increases between the radial distances (r-rdfrom the location (W) where the material leaves the guide member (8) and a hit location (T) situated further on in the stream (S).

Furthermore, the impact velocity (Vh,, is determined by the angular velocity (Q).

Figure 48 shows how the relatively velocity (Vre,) of a grain develops along the spiral stream (S). At the moment at which the grain is guided into the spiral stream (S), only the radial velocity component is active, i. e. : Vrel = Vr ; at that moment, the grain has no transverse velocity component (Vt = 0). As stated above, the radial velocity component (Vr) increases for both the absolute velocity (vab5) and the relative velocity (are), when seen from the axis of rotation (O), as the grain moves further away from the said axis of rotation (O), thus : vr = Vr. Immediately after the grain comes off the guide member (8), it develops, along the spiral stream (S), a transverse velocity component (V,) which increases considerably as the grain moves further away from the axis of rotation (O). This transverse velocity compo-

nent (Vt) is calculated as the distance, at a specific radial distance from the axis of rotation (O), between the relative tip velocity (V', ip) of the grain, which is calculated as Vtip ' = #r, and the transverse velocity component (vt) of the grain along the straight stream (R) at the said radial distance, i. e. : V rel = Vtip' - vt' = #r - vt'. The relative velocity (V), i. e. the impact velocity (Vhnpac,), is now, when seen from the axis of rotation (O), formed by the resultant of the radial (V) and the relative transverse (V) velocity components. It is clearly illustrated how considerably the relative velocity (Vre,) increases along the spiral stream (S) as the grain moves further away from the axis of rotation (O).

Figure 49 indicates how the velocity at which the material hits the rotating impact member (14), i. e. the impact velocity (Vimpact), can be reached. This impact velocity (V,,,- pact) essentially satisfies the equation : 2 2'2 Vunpact- This specific connection makes it possible, at a given location (T) where the material hits the rotating impact member (14), accurately to give the angular velocity (Q) which is required in order to achieve a specific impact velocity (V,. P.). Conversely, if the angular velocity (Q) is given, the hit location (T) where the material hits the rotating impact member (14) at a defined impact velocity (Vimpact) can be defined accurately.

For two angular velocities (# = 1000 and # = 1200 rpm), Figure 50 shows the relative velocities (Vrel = Vimpact) which the material develops along a specific spiral stream (S) ; i. e. the velocity (V ) at which the material at the location (T) in the spiral movement (S) would strike a rotating impact member (14) disposed at that location. The basis used here is a tip velocity (Vtip), i. e. peripheral velocity (V, ip), at the location (W) from where the material comes off the guide member (8), of 36 m/sec. The method of the invention thus makes it possible, at a relatively low take-off velocity (vau5), to achieve a very high collision velocity (Vimpact), and thus a high impulse loading of the material, which impact velocity (Vhnpac,) can be selected with the aid of the angular velocity (Q) and the radial distance (r) from the axis of rotation where the rotating impact member (14) is arranged in the spiral (S).

It is preferred for the material to hit the impact face (15) of the rotating impact member (14) perpendicularly, when seen in the plane of the rotation and when seen from a viewpoint which moves together with the rotating impact member (14). The actual impact angle (ß) can then be adjusted by tilting the impact face (15) in the vertical direction.

Figure 51 shows how the impact face (15) has to be arranged in order to achieve a

perpendicular impact angle in the plane of the rotation, at the location where the grain strikes the said impact face (15) : at an angle (ß') in the horizontal plane, between the radial line (48) on which is situated the location (W) from where the material leaves the guide member (8) and the line (49) which, from the location (T) where the material hits the impact face (15), is directed perpendicular to this radial line (48), which angle (ß') essentially satisfies the equation : 2 r2 cos oc r cos cp rl cos a. f rl a p sin a + rl = arctan-6 rlsina, +p With the aid of the angle (ß'), it is possible to arrange the impact face (15) in such a manner that the impact of the stream of material (S) takes place at an optimum impact angle (p), which lies, as indicated above, between 75° and 85° for most materials. At the same time, the impact angle (p) is largely the determining factor for the rebound behaviour of the grains ; i. e. the rebound velocity (Vresidual) the rebound angle (p) and the behaviour of the granular material which remains stuck to the impact face (15) during the impact.

This is the case in particular if the grains have a low coefficient of restitution, and above all if the grains become pulverized during the impact. This adhesion behaviour is promoted if the grains are moist. Disposing the impact face (15) at a slightly oblique angle with respect to the impacting stream (S) has the advantage, in addition to increasing the breaking probability, of guiding the grains in a different direction after the impact, so that the impact of following grains is not disturbed. Furthermore, it is necessary to prevent the grains from starting to move outwards, after impact, radially along the impact face (15) under the influence of the centrifugal force. Since the peripheral velocity (V'tjp) is relatively high at that location, this can lead to extremely intensive wear along the outer section of the im- pact face (15). This wear disturbs the impact process and does not lead to significantly greater rebound velocities, i. e. residual velocity (Vresidual), of the rebounding stream of material (Srfflsidual) It is therefore preferred to direct the impact face (15) slightly obliquely inwards and slightly obliquely downwards with respect to the impacting stream (S).

Figure 52 shows a preferred arrangement of an impact face (170). In this case, the impact face (170) is directed slightly inwards in the horizontal plane (Figure 53), so that the angle (ß") is a few degrees (1° to 5°) greater than the calculated angle p' ; in such a

manner that, when seen in the plane of the rotation, the said angle (ß"), which the said impact face forms with the spiral stream (S) at the location of impact is greater than 90°, when seen from a viewpoint which moves together with the said rotating impact member.

In the vertical plane (Figure 54), the impact face (170) is directed slightly downwards, with the angle (ß"') being a few degrees (1° to 5°) ; in such a manner that, when seen from the plane directed perpendicular to the plane of the rotation, the said angle (ß"'), which the said impact face forms with the spiral stream (S) at the location of impact is greater than 90°, when seen from a viewpoint which moves together with the said rotating impact member.

Overall, the angles (3"and (3"'must be selected in such a manner that the actual impact angle (p) lies between 75° and 85°. An arrangement of this kind is possible with the aid of the calculated angle (p').

Figures 55, 56 and 57 show how a jet of air (91) can be blown in a simple manner and at great speed along the impact face (131), from the top towards the bottom, thus assisting the movement of adhering material in a direction which is as far as possible vertical, downwards along the impact face (131), while the stream (Sresidual) of the rebounding material is guided more effectively. The jet of air (91) is generated with the aid of an air- guidance member (127) in the form of a partition (128) which is disposed along the top of the edge (130) of the rotating impact member (131).

The spiral streams which the grains describe between the guide member and the im- pact face may shift slightly as a result of natural effects.

Figure 58 shows the influence of the grain diameter. Since larger grains (153) make contact with the delivery end (11) for a somewhat longer period, to a somewhat greater distance from the axis of rotation (O), than smaller grains (154), larger grains (153) develop a somewhat greater take-off velocity (Vabs), and come off the delivery end (11) at a somewhat greater take-off angle (a) than smaller grains (154). The stream (155) of larger grains (153) therefore shifts outwards to some extent by comparison with the stream (156) of smaller grains (154). The length () of the guide member (8) can therefore be calculated as the length to the delivery end (11), increased by half the grain diameter.

The factors mentioned above explain why the particles from the stream of grains (S) exhibit a certain spread (157) along the rotating impact face (15) as has been mentioned ; this spread (157) increases further on in the stream (S).

Figure 59 shows how the spiral stream (S) can shift slightly owing to the self-rotation (158) of the grain in this stream (S). This is true in particular of elongate grains.

Figure 60 and Figure 61 show a different behaviour of grains along the guide face

(15). The grain can roll along this face (Figure 60), but can also, as is generally the case, slide along it (Figure 61). The coefficient of friction (co) for rolling friction is normally less than for sliding friction, and as such affects the take-off velocity (v) and the take-off angle (a), although only to a limited extent.

Figures 62 and 63 show that the contact surface (159) (160) between the grain and the guide face (10), depending on the shape of the grain, can differ considerably, which can affect the friction behaviour and thus the take-off behaviour to some extent.

Figure 64 shows that, owing to the abovementioned natural effects, the streams (S) which the separate grains from the material (S) describe as a whole form a bundle of streams (161). This behaviour is inherently essentially deterministic and controllable. As a result, the impacts become spread slightly over the impact face (15), with the result that a more regular wear pattern is produced. An extensive concentration of the impacts can lead to an irregular wear pattern, which can impair the impact of the grains. These natural effects must be taken into account when designing the impact face (15) by, as far as possible, adapting the design to the impact pattern (162) of the stream of material (161). As a general rule, it can be stated that the natural spread of the streams (161) which the grains describe, i. e. the extent to which the spiral streams (S) shift, increases as the stream of material contains grains with more divergent diameters, grain shapes which differ to a greater extent and as the material compositions of the grains differ increasingly, with differing coefficients of friction (co).

The impact pattern (162) has a major effect on the wear behaviour and is thus of great importance if the impact face (15) is to be designed optimally. In theory, the impact pattern (162) can be approximated effectively with the aid of computer simulation, but this simulation has to be checked and corrected using practical observations. An insight into the impact pattern (162) makes it possible to design a wear-resistant impact segment which has a relatively long service life.

To achieve a regular wear pattern, it is important that the impacts of the various particles against the impact face of the impact member take place at an angle which is as far as possible identical ; this is also of importance in order to achieve a broken product with a constant quality and a low spread in the grain size distribution. The impact face of the impact member may therefore be designed to be hollow, or curved once or twice. By designing the curvature (528) as shown in Figure 65, along a radius (r] pact) directed from the location (529) where the line (530) on which is situated the location (531) where the material leaves the guide member (532) and the line (533) on which is situated the location (534) where the material hits the guide member are perpendicular to each other. This

curvature reasonably approximates the curve with which the spiral movements (S) turn off, directed from the delivery point (531) of the guide member (532). For a single curvature, the impact face can be curved along the circle with radius (rimpact) with the location (529) as the centre point. For a double curvature, the impact face can be curved along the sphere with radius (rP), with the location (529) as the centre point.

The impact element (520) may, as shown in Figure 66, be of composite design, i. e. designed in the form of segments (521) which fit inside one another and have differing hardnesses (brittlenesses), so that the wear as far as possible takes place uniformly along the impact face. The structure (520) must in this case be adapted accurately to the wear pattern, the harder, more brittle material being employed where the impacts are concentrated (523).

As shown in Figures 67a and 67b, the impact face may also be provided with cavities or openings of another kind, in which material accumulates, so that a partially autogenous impact face of the same material is formed.

As shown in Figure 68, the impact element (520) may also be placed in a frame structure (524), the same material (527) accumulating between the edge (525) of the im- pact segment (520) and the edge (526) of the frame structure (524), thus preventing material which bends off in the spiral path from shooting outwards along the impact element (520).

Figure 69 and Figure 70 show a guide member (163) with a guide segment (164).

The wear along the guide face (165) of the guide segment (164) increases with the radial distance (rl) to the axis of rotation (O), i. e. outwards. As wear occurs, therefore, the guide face (165) is gradually curved backwards to a greater extent, when seen in the direction of rotation.

With increasing wear, the location (167 168) from where the material leaves the guide member (163) shifts backwards, when seen in the direction of rotation. As a result, the stream (S) which the particle describes between the guide member (163) (8) and the rotating impact member (14) also shifts backwards, when seen in the direction of rotation.

By making the impact segment (164) less thick at the location of the central inlet than at the delivery end (167), the effect is achieved that ultimately the guide segment wears away entirely.

As indicated above, the deterministic process may also be the cause of the impacts of the particles against the impact members taking place in a very concentrated manner. This may lead to such an iiregular wear pattern of the impact face of the impact member that the breaking process is interfered with. It is then important to implement measures which promote a spread of the impacts over the impact face. As explained above, the paths of

different particles, for example with different diameters, already exhibit a certain level of spread. However, with the aid of the guide member and the impact member it is also possible to increase the spread of the impacts ; at the same time, the impact segment of the impact member may be dimensioned and constructed in such a manner that it is able to deal with a more concentrated impact pattern.

A shift (513) of the location where the particle, under the influence of wear (514), touches the impact face (515) can, as shown in Figure 71 and Figure 72, partially be prevented by not making the delivery end (516) straight, when seen in the horizontal plane, but with a length which increases towards the rear, when seen in the direction of rotation.

On the other hand, by making the length of the delivery end (517) decrease towards the rear, when seen in the direction of rotation, as shown in Figure 73 and Figure 74, the shift (513) of the path (S S'), with increasing wear (518) to the delivery end (517), is promoted. This is often preferred, since this allows the impacts of the particle against the impact face (515) to be spread better and more quickly, with the result that it is possible to achieve a more regular wear pattern.

This process may, as shown in Figure 75, also be promoted by curving the delivery end (519) progressively towards the rear.

Figures 76 and 77 show how, in the event of the impacts of the grains becoming concentrated on a specific point on the impact face (15), due to the composition of the granular material being so uniform that a natural shift of the stream of material (S) is limited, these impacts can be spread apart in a simple manner. To do this, the guide member (97) is suspended in a pivoting manner, with the aid of a vertical hinge (98) which is fastened to the rotor (2) along the edge of the metering face (3). The radial distance (100) from the axis of rotation (O) to the pivot point (99) must in this case be smaller than the corresponding radial distance (100) to the mass centre (102) of the pivoting guide member (97). Under the effect of the rotating movement of the rotor (2), the pivoting guide member (97) becomes directed radially outwards, but under the effect of a natural, slightly fluctuating loading of the guide face (167) by the stream of material (Sr), a certain degree of reciprocating movement of the delivery end (168) can occur. The angle () which the delivery end (168) then forms with respect to the radial line on which is situated the location of the pivot point (99) can be limited both forwards and backwards. The degree to which the delivery end (168) moves in the process can be controlled using the distance (169) between the pivot point (99) and the mass centre (102) of the pivoting guide member (97). The smaller this distance (169) is made, the more the movement of the delivery end (168) increases. A pivoting guide member (97) of this kind moreover has the advantage that the spiral

movement (S) is affected to a lesser extent by the wear along the guide face (167).

Figures 78 and 79 show that, in the event that the stream of material (S) exhibits an excessive spread owing to natural or other effects, this can be corrected using the subsequent guide member (12), which is disposed with the subsequent guide face (13) along at least a section of one side of the spiral stream of material (S). A subsequent guide member (12) of this kind makes it possible also to gain better control of the air movement, in addition to the stream of grains.

It is necessary to prevent the stream (S) which the grains describe from being affected excessively by air movements. The air in the cylindrical chamber (20) between the guide member (8) and the rotating impact member (14) has to flow at virtually the same velocity and along the same spiral stream (S) as the said material, so that, as it were, a dish of air is formed in the circular chamber (20), which dish rotates in the same direction, at the same angular velocity (Q) and about the same axis of rotation (O) as the said guide member (8) and rotating impact member (14).

The central feed, the guide face and the delivery end are each subject to different forces. The central feed is exposed to impact forces which concentrate on the start point and is further affected by both rolling and sliding friction. The guide face is exposed primarily to friction forces which are mainly caused by sliding friction, the sliding friction increasing exponentially towards the end point of the guide face. The delivery end is exposed to a sudden (total) cessation of the normal loading at the moment at which the grains leave the delivery end, resulting in intense friction and wear. It is therefore preferred to design the various components of the guide member to be (geometrically) different specifically in such a manner that these components are best able to withstand the forces indicated. An important aspect is the selection of the construction materials. Ceramic materials offer advantageous possibilities in particular for the guide face. However, composite materials also offer advantageous possibilties.

Figure 80 shows a wear pattern (198) as is developed along the guide face and delivery end of a guide member (171) which is made of hard metal, possibly a composite metal. As the wear increases, it becomes more and more concentrated on the centre of the guide face (172), the wear increasing in the direction of the delivery end. A problem with a wear pattern (198) of this kind is, in addition to the cost aspect, that, owing to the fact that the material stream becomes concentrated in the centre along the guide face (171), the movement of the material along the spiral stream (S) is also concentrated, with the result that the impacts against the impact face (15) of the rotating impact member (14) also become concentrated, so that irregular wear on the impact face (15) may arise, which can lead to an

irregular impulse loading of the impacting material. Moreover, a concentration of the material stream (Sd) along the guide face (198) is the cause of the deterministic capacity of the guide member (14) decreasing. It is known that a guide face which is composed of ceramic material provides a more uniform wear pattern along the guide face. A drawback of ceramic is that it is not really intended for impact loading.

Figure 81 diagrammatically shows a guide face with delivery end with a layered design, layers with a high wear resistance (312) being stacked alternately on layers with a less high wear resistance (311) ; a structure of this kind is composed of at least five layers, with the bottom layer (313) and the top layer (310) made from a material with a high wear resistance. The wear now becomes concentrated along the layers (311) with the lower wear resistance, with the result that a number of guide channels (314) are formed, along which the material stream is guided outwards and concentration is avoided or, as it were, spread.

Figure 82 shows a guide member (501) with a layered design in which the layers (502) are disposed parallel to one another, at a slight acute angle (e). This has the advantage that the material which moves outwards, under the influence of the centrifugal force, in a virtually horizontal direction (503) along the guide member (501) is essentially unable to form any guide channels (314), so that the wear develops in a regular manner along the guide face and concentration towards the centre is avoided. It is preferred here to direct the angle (e) at which the layers (502) are disposed towards the outside, when seen from the axis of rotation (O), slightly downwards, the start point (504) of the layers along the guide face one grain diameter (D') being brought downwards towards the end point (505). The angle (e) at which the layers have to be disposed for this purpose essentially satisfies the equation : D' £ = arctan A (weighed) average diameter of the granular material may be taken as the grain diameter (D').

Figure 83 shows a very diagrammatic cross-section of a rotor blade (506), the guide members (507), which are of layered design, along the conical metering face (508) being disposed inclined downwards slightly, which means that the guide members (507) of layered design do not have to be designed with inclined layers. An arrangement inclined slightly downwards in this way moreover has the advantage that the material is guided outwards in a more natural way. The guide members may here be disposed at the angle (e) calculated

above.

The principle of integration means that the progress of the wear (192), with the shift of the spiral (S), as shown in Figures 84a, 84b and 84c, takes place simultaneously along both the guide surface (193) of the guide member (194), as far as possible are adapted to one another, specifically in such a manner that the wear (195) to the guide member (194) progresses, as it were, synchronously with the wear (192) to the rotating impact member (196), so that both elements (194) (196) are worn away and can be replaced virtually simultaneously.

Figure 85 shows a further design of the impact segment, specifically in the form of an elongate, curved impact block (458), a top end (456), which functions as the impact side, being directed transversely to the spiral path (S) which the material describes, when seen from a viewpoint which rotates together with the guide member (455).

In the process, the curvature (457) of the impact block (458) follows the course of the spiral path (459) which the material would describe if it were not impeded by the impact face (456), in such a manner that the impact face (456) remains directed transversely to the path (S) which the material describes when the impact face (456), under the influence of wear to the impact block (458), moves towards the rear.

As indicated in Figure 86, it is necessary here for the curvature (465) of the impact block (463) to be corrected, or integrated, when the spiral path (S-> S') which the material describes is shifted as a result of the wear along the delivery end (460) of the impact block (463).

In this design, it is necessary to take into account the fact that the impact face (462), as the wear (461) to the delivery end (460) increases, shifts further to the rear (464) in the path (S') of the grain and consequently the collision velocity increases. This can be corrected by periodically moving the impact face (464) forwards. It is more simple gradually to reduce the angular velocity, thus simultaneously saving energy. In relative terms, a very great amount of material can be processed using an element of this kind.

However, it is also possible, and this is preferred, to design the shape and the positioning of the guide face of the guide segment to be curved towards the rear, in the longitudinal direction, when seen in the direction of rotation and when seen in the plane of the rotation, in such a manner that the potential loading along the guide face is distributed more regularly, specifically in such a manner that the potential loading is virtually constant from the feed end to the discharge end of the guide member, so that the wear along the guide face is virtually uniform and so that the shape, i. e. the curvature, does not change significantly under the effect of the wear, but rather shifts in its entirety towards the rear, when seen in

the direction of rotation.

As shown in Figure 87, the design of the impact block can thus be integrated, in which case it is possible to design this impact block segment in the form of a curved impact block (466) with the axis (467) curved virtually, or at least strongly, in the direction along the circumference (168) along which the impact block (466) rotates. In a design of this kind, the radial distances from the axis of rotation (O) to respectively the location (469) from where the material leaves the guide face (470) and the location (471) to the axis (467) of the impact block (466), together with the selection of the materials from which the guide segment (470) and the impact block (466) are constructed, must be accurately adapted to one another.

It is possible here, as shown in Figure 88, to design the guide member (470) in the form of parallel segments (471) positioned one behind the other, and also to design the impact block (472) in this way with segments (473), thus making it possible, in the event of irregular wear, to repair this along the various blades.

A regular distribution of the wear can also be achieved by making the impact member rotatable with a rotationally symmetrical impact face.

Figure 89 shows an impact member (316) which is rotatable about a horizontal, outwardly directed axis (317), when seen from the axis of rotation (O), and is equipped with a cylindrical, rotationally symmetrical impact face (319). As indicated in Figures 90 and 91, the impact face (318) may be of conical design, the impact face (319), in cross- section, being curved in such a manner that the impacts in the plane of the rotation take place at an angle which is as far as possible perpendicular, when seen from a viewpoint which moves together with the impact member. The material which strikes a rotationally symmetrical impact face (319) (318) of this kind is in the process turned out of the plane of the rotation, so that the impact face is always freed for subsequent impacts.

Figure 92 shows an impact member (323) which is rotatable about a vertical axis (324) and is equipped with a cylindrical, rotationally symmetrical impact face (325).

The impacts against a spherical surface provide a high level of impulse loading for the granular material, and hence a high breaking probability.

Figure 93 shows an impact member (326) which rotates about a horizontal axis (327), which is essentially in line with the spiral stream (S), and is equipped with a rotationally symmetrical impact face (328) in the form of a flat disc (329).

Figure 94 diagrammatically shows the impact and the rebounding of the material at the location on the rotating impact face, which impact takes place at a predetermined angle (a) on a predetermined hit location (T) and with an impact velocity (Vi", paC,) which can be

selected with the aid of the angular velocity (U), the rebound behaviour being determined by the collision partners.

Figure 95 diagrammatically shows the impact of the grain against the impact face (15) of the rotating impact member (14), and how this grain then comes off and is guided in a further stream (Sresidual). With the aid of the already calculated impact velocity (V) and the impact angle (p), it is possible, with the aid of the coefficient of restitution, within the model shown, to calculate the rebound velocity (Vresjdu31) and the rebound angle (ßr).

Figure 96 diagrammatically illustrates the movement of the grains between the rotating impact member (14) and the stationary impact member (16). The velocity (Vresjdual) of the material when it comes off the impact face (15) of the rotating impact member (14) is at least equal to the absolute transverse velocity, i. e. the tip velocity (Vip) of the rotating impact member (14). The impact against the collision face (17) of the stationary impact member (16) therefore takes place at a relatively great velocity, i. e. at a velocity (Vn,,,.,,,) which is at least equal to, and often greater than, the velocity (V, l,, pac,) at which the material hit the rotating impact member (14). Moreover, the impacts against the respective impact faces (15 17) take place in quick succession and at an optimum impact angle. Depen- ding on the position of the two impact faces (15-> 17), the grains in the process have to cover a shorter (a) or longer (a2) distance. Figure 97 shows the grain movements, i. e. the trajectories (74), which the grains describe between the rotating impact member (14) and the stationary impact member (16). The trajectories (174) which the grains describe together form, as it were, a trajectory plane (175). Figure 98 depicts the trajectory plane (175) in horizontal section. It is possible to differentiate here between an upper trajectory plane (176), a lower trajectory plane (177) and a trajectory turning point (K), the radius of which is equal to that of the inscribed circle (178) which the trajectories (174) describe. No impacts take place inside this inscribed circle (178) or trajectory turning point (K). It is furthermore important, since the trajectories between them cany out a type of"helical motion" (180) in the trajectory plane (174), as indicated in Figure 99, that the grains are first guided out of the upper trajectory plane (176) to the lower trajectory plane (177), before they strike the collision face (17). It is necessary here to guide the grains over the edge (179) of the stationary impact member (16). At the location where the trajectory plane (175) intersects this upper edge (179), the straight streams (R), i. e. the trajectories, of the grains can be affected. The grains with the short trajectories (a1) strike the top of the collision face (17) at a first radial distance from the axis of rotation (O), and the grains with the long trajectories (a2) strike the bottom of the collision face (17) at a second radial distance which is greater than the first radial distance. This can be taken into account when

designing the stationary impact member (16), which for this purpose can be designed with an oblique upper edge (179).

As has been stated, the method of the invention makes it possible to achieve relatively great impacts in quick succession, first against the impact face (15) and then against the collision face (17), using a relatively short guide member (8) and consequently with relatively low power consumption and, as a result, limited wear. This is achieved essentially by guiding the material in an uninterrupted spiral stream (S), when seen from a viewpoint which moves together with the rotating impact member (14), through a co-rotating breaking chamber (20) which, as it were, is moving, in which breaking chamber (20) the movement of the impact face (15) is synchronized with the spiral movement (S) of the material in such a manner that the material strikes this impact face (15) without making contact with the edges of the rotating impact member (14), which permits an essentially undisturbed, deterministic progress of the material movement and the first impact. If the material is guided out of the moving, rotating chamber (20), after the impact, in particular the upper edge (179) of the stationary impact member (16) provides an interfering influence. By extending the collision faces (17) as far as possible outwards, the number of collision faces (17) can be reduced considerably, as indicated in Figure 99, and thus so can the abovementioned interfering influence. By curving the collision faces (17) along an involute, it is possible to make the grains, when seen from a horizontal plane, impact as far as possible perpendicularly.

As indicated above, the movement equations given apply to an idealized, resistance- free state. In reality, it is necessary, when determining the spiral stream (S) which the material describes between the guide member (8) and the rotating impact member (14), when seen from a viewpoint which rotates together with the system, to take into account the effects of, inter alia, the friction of the material with parts of the system, the airresistance, air movements, any inherent rotation of the material and the force of gravity. Although the nature of the movement (S) does not change significantly under the influence of these factors-the material has a relatively great velocity and the distance which the material covers between the guide member (8) and the rotating impact member (14) is relatively short-, it is nevertheless necessary to take into account the fact that a certain degree of spread will occur in the streams (S) which the material describes between the location (W) where it leaves the guide member (8) and the location (T) where the material hits the rotating impact member (14).

The method of the invention thus makes it possible, as indicated in Figure 100, to optimize the design parameters, namely the radial distances to the central feed (r0), the

length (fol) of the guide member (8), including the length of the central feed (suc) and the guide face (tu), the radial distance (rl) before the said delivery end (11), the radial distance (r) to the rotating impact member (14), the instantaneous angle (6) between the guide member (8) and the rotating impact member (14) and the angle (p) at which the impact face (15) has to be arranged. Furthermore, these parameters make it possible to arrange the stationary impact member (16) as effectively as possible in the straight stream (Rresidual) which the material describes when it comes off the impact face (15), when seen from a stationary viewpoint.

The method of the invention furthermore makes it possible to implement a number of principles which make it possible to optimize the process further, namely the principes of differentiation and segmentation.

Since the impacts of the material against the various rotating impact members (14) form essentially individual processes, it is possible to load the material differently in these separate processes. Figure 101 shows the principle of differentiation, by means of which different loadings of this kind can be realized by comparison with an undifferentiated system (Figure 102). In the undifferentiated system (58), the impact members (14) are disposed at equal radial distances (r) and are distributed uniformly around the axis of rotation (angle 0). The impact intensity of each rotating impact member (14) is consequently identical. In the differentiated system, the impact members (38) (39) are positioned at dif- ferent radial distances (r') (r") in the spiral movement (0"). Consequently, there are, as it were, a plurality of breaking processes with different intensities functioning simultaneously next to one another. The particles are hit at a lower collision velocity by the rotating impact member (39) which is disposed at a short radial distance (r') (6') than by the rotating impact member (38) which is disposed at a greater radial distance (r") (6"). The result is broken products with different grain size distributions, which moreover are immediately mixed with one another again. The principle of differentiation consequently makes it possible to control to a considerable extent the grain size distribution.

Figure 103 shows the grain size distribution, for different impact velocities, which is obtained with a crusher in which the rotating impact members (14) are not disposed in a differentiated manner and function identically. In this figure, the cumulative amount (181) of material is shown on a smaller scale than the specified diameter (182). The grain size distribution of the broken material is indicated by curve (183). As the collision velocity increases, the grain size distribution shifts in a direction (184) from a coarse (185) range to the fine (186) range and normally continues to run continuously. The grain size distribution can in this case essentially be affected only by the angular velocity (Q). In this case, the

grain size distribution, by changing the velocity, can essentially only be shifted from coarse (185) to fine (186). It is not possible to affect the grain size distribution otherwise.

Figure 104 shows the grain size distribution, for a specific collision velocity, which is obtained with a crusher with a differentiated arrangement of the impact members. The grain size distribution of the broken material is shown by the curve (183). The figure further shows the sieve analyses of a relatively coarse, first broken product (187), which is produced with the rotating impact member at a short radial distance (r') and consequently a relatively low collision velocity, and the sieve analysis of a relatively fine second broken product (188), which is produced with the rotating impact member at a great radial distance (r") and consequently a relatively great impact velocity (V""pac,), or at least an impact velocity (V", n, pac,) which is greater than the impact velocity (V'"pac,) at which the first broken product is produced. The result is thus, as it were, two different broken products at the same time, namely a fine broken product (188) and a coarse broken product (187), which moreover are immediately mixed. The combination of the fine product (188) and the coarse product (187) here provides a broken product with a grain size distribution (189) which cannot be produced directly using a crusher with an undifferentiated arrangement of the rotating impact members (14). In this way, it is basically possible to achieve"all possible" grain size distributions, including discontinuous grain size distributions (189), an example of which is given here. By making the radial distances (r,/r") at which the impact members are disposed adjustable, it is possible in this way substantially to control the grain size distribution.

The principle of differentiation can be implemented further with the aid of the principle of segmentation.

The material, when it is metered onto the rotor (2), is guided outwards, when seen from the axis of rotation (O), in a spiral movement (Sr), when seen from a viewpoint which rotates together with the rotor (2), which spiral movement (Sr) is directed backwards, when seen in the direction of rotation. Since the spiral movement (Sr) is interrupted by the guide members (8), there are formed, as shown in Figure 105, as it were, feed segments (32) of material which is moving outwards in a spiral stream (Sr) and is taken up by the central feed (9) of the guide members (8), from where it is accelerated and flung outwards.

As shown, in the event that the start points (33) of the guide members (8) are situated at identical radial distances (Ro) from the axis of rotation (O) and are distributed regularly around the central part of the rotor (2), the granular material from the central part is also distributed regularly over the various feed segments (32) between the guide members (8).

By varying the radial distances (r') (r") from the axis of rotation (O) to the central feed

(30) (31) of the guide members (24) (25), as is shown in Figure 106, the effect is achieved that the feed segments (190) (191), from where the grains are fed to the guide members (24) (25), cover different areas, with the result that the various guide members (24) (25) are fed with different amounts of material. Less material is taken up by the guide member (24) which is disposed with the central inlet (30) at a greater radial distance (ro") from the axis of rotation (O) than by the guide member (25) which is disposed with the central inlet (32) at a shorter radial distance (ro) from the axis of rotation (O). This makes it possible to feed the rotating impact members (16), which are arranged in a differentiated manner at diffe- rent radial distances (r') (r"), with different amounts of material, with the result that the quantities of coarse and fine broken product which are produced can be controlled further, and thus so can the grain size distribution.

The method of the invention makes it possible to comminute granular material having dimensions between 3 mm (or even 1 mm) and about 100 mm, it being possible to achieve a high level of comminution ; depending on circumstances, a degree of comminution of more than 25.

To comminute material finer than 1 to 3 mm, the rotor and the stationary impact members must be disposed in a chamber (not shown here) in which a partial vacuum can be created, so that there is no hindrance from air resistance and air movements. An arran- gement of this kind makes it possible to achieve extremely great fineness, down to less than 5 m, with a relatively low power consumption and, by comparison with known systems, with relatively low wear.

Furthermore, the rotor and the stationary impact member may be disposed in a chamber (not shown here) in which a low temperature can be created. This makes it possible to increase considerably the brittleness of certain materials, with the result that a much better breaking probability is achieved.

Naturally, it is also possible to set a high temperature and a high pressure in the chamber where the rotor and the stationary impact member are disposed ; combinations of vacuum and high pressure with high and low temperatures are possible.

The following figures show a number of embodiments according to the method of the invention for devices and a rotor for breaking granular material. All the rotors described are equipped here with four guide members and four associated impact members. It is clear that the rotors may be equipped with fewer and, within practical limits, with more guide members and associated impact members. It is also clear that the various components which are described for the various devices may be combined with one another in other ways and that all the rotors described may function without a stationary impact member.

Figure 107 and 108 diagrammically show a first embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way.

The material to be broken is fed centrally onto the top of the rotor (52) via a feed pipe (200). The rotor (52) bears four guide members (58), which are distributed evenly and are disposed at a radial distance around the axis of rotation (O). Each of the guide members (58) is provided with a central feed (59), guide face (60) and delivery end (61). The stream of material (Sr) which is metered onto the central part of the rotor (52) is accelerated with the aid of the relatively short guide members (58) in the direction of the rotatable impact members (64), which are associated with each guide member (58) and are disposed, at a greater radial distance from the guide members (58), along the edge (201) of the rotor (52), and are supported by the said rotor (52). From a coordination system which is fixed with respect to the rotor (52), the material, when seen from a viewpoint which moves along with the rotatable impact member (64), moves along the spiral path (S) towards the impact fact (65) of the rotatable impact member (64). Thus in this case, when seen in the plane of the rotation and when seen from a viewpoint which moves along, the impact face (65) is directed virtually transversely to the spiral stream (S) of material. After impact against the rotatable impact member (64), the stream of material is accelerated again by the rotatable impact member (64) and is flung at great speed against a stationary armoured ring (202), which is arranged around the rotor (52) and is fastened against the outer wall (203) of the crusher housing (204). The armoured ring (202) comprises separate segments (205) which are each provided with an impact face (206) which is arranged virtually transversely in the straight stream (R) which the material describes when it comes off the rotatable impact member (65), when seen from a stationary viewpoint. The stationary armoured ring (202) as a whole therefore has a sort of knurled shape. In this embodiment, a stream (S) (R) of material is subjected to direct multiple (double) loading, the impacts taking place at a virtually perpendicular angle.

Figure 109 and 110 diagammically show a second embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way.

The material to be broken is metered onto a stationary plate (208) centrally above the rotor (207), via a feed pipe (200), which plate interrupts the fall of the stream of material.

The material then flows to a following horizontal plate (209) situated at a lower level, which is provided in the centre, centrally above the rotor (207), with a round opening (210), through which the material, via an opening (212) in the centre of a first rotor blade

(211), is moved onto the metering face (213) of a second rotor blade (214), which second rotor blade (214) is supported by the same shaft (215) as the first rotor blade (211), but has a smaller diameter than the first rotor blade (211). The second rotor blade (214) is connected to the first rotor blade (211) by means of projections (216) which are disposed behind the guide members (217). The metering face (213) is designed in the form of an upright cone, so that the material is guided outwards in a flowing movement, towards the relatively short guide members (217) which are disposed along the edge (218) of the second rotor blade (214). The stream of material (S) is accelerated with the aid of the guide member (217) and is flung outwards from the delivery end (219) and guided along a spiral path (S), when seen from a viewpoint which moves together with the rotor (207), freely through the air in the direction of a rotatable impact member (220) which is associated with the said guide member (217) and is freely suspended, at a greater radial distance from the axis of rotation (O) than the guide member (217), along the bottom of the edge (221) of the first rotor blade (211). After the material has struck the impact face (222) of the said freely suspended, rotatable impact member (220) and has come off the latter, the stream of material (R) strikes the collision faces (223) of stationary impact members (224) which stand in the straight path (R) which the material now describes, when seen from a stationary viewpoint.

These stationary impact members (224) are fastened to the outer wall (225) of the rotor housing (226). The impact face (222) of the rotatable impact members (220) is directed slightly obliquely inwards and slightly obliquely downwards, in such a manner that the material is guided, from the periphery (221) which the rotatable impact member (220) describes, obliquely downwards out of the rotor (207), along a straight, virtually tangential stream (R). The collision faces (223) of the stationary impact members (224) are curved concavely, in accordance with the involute which the stream (R) describes from the said periphery (221), so that the impacts of the grains from the stream of material (R), when seen from the plane of the rotation, take place as far as possible at a perpendicular angle. In the vertical plane, the collision face (223) can be tilted in such a manner that the impacts take place as far as possible at an angle of between 80 and 85°. The stationary impact member (227) is arranged along the bottom of the edge (220) of the rotatable impact members (220) and is continued outwards, so that the number of stationary impact members (224) is limited as far as possible. Furthermore, the collision faces (223) are continued upwards to some extent along the outside of the rotatable impact members (220), so that there too material can be taken up. The freely suspended, rotatable impact members (220) have the advantage that there is no hindrance from rebounding material, while this design permits simple suspension of the rotatable impact members (220).

Figure 111 and 112 diagrammically show a third embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, and at the same time treating the grain shape of the broken product.

The material to be broken is metered onto a stationary plate (230) centrally above the rotor (229), via a feed pipe (200), which plate interrupts the fall of the material. The plate (230) is designed in the form of an upright cone, so that the material is guided further in a flowing movement. The material flows along the plate (230) to a subsequent plate (231), which is disposed in the centre, centrally above the rotor (229), and is provided with a round opening (232), through which the material is moved evenly onto the metering face (233) of the rotor (229), which metering face (233) is likewise designed as an upright cone. The stream of material (Sr) is accelerated along guide members (234) which are disposed along the edge (235) of the rotor (229), and, from there, in free flight, are guided to the associated impact members (236) which, at a greater radial distance from the axis of rotation (O) than the impact members (234), are fastened to arms (237) which are supported by the rotor (229). After the stream of material (S) has struck the impact face (238) of the rotatable impact members (236) and comes off it, the material is guided into a trough structure (239), which is disposed around the outside of the rotatable impact members (236), with the opening (240) directed inwards. A bed of the same material (241) builds up in the trough structure (239), against which bed of material the material then impacts. The autogenous action, i. e. the intensive rubbing of the grains against one another, provides a high level of cubicity of the broken product.

As depicted diagrammatically, the stream of material (R), after it comes off the rotatable impact member (236), may be guided, depending on the angle at which the impact face (238) is disposed in the vertical direction, towards the autogenous bed (241) respectively in a horizontal movement (241), a movement directed obliquely upwards (242) and a movement directed obliquely downwards (243). This makes it possible to adapt the autogenous process, together with the arrangement of the height of the trough structure (239), to the material. In the event of a large number of fine particles being formed, the autogenous bed (241) has the tendency to take up too much fine material, with the result that the bed, as it were, dies. This can be partially prevented by arranging the bed somewhat higher and guiding the stream of material (242) slightly obliquely upwards into the bed (241). In the event that not so many fine particles are formed, the autogenous bed (241) may be arranged at a lower level and the material can be guided into this bed obliquely from above (243), so that the autogenous intensity is increased. For this purpose, the device is equipped with a trough structure (239) whose height (244) can be adjusted.

Figure 113 and Figure 114 diagramatically show a fourth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way.

The material is fed centrally above the rotor (246), via a feed pipe (200), onto a stationary, round plate (245), which is provided along the edge (247) with an upright rim, so that a bed of material is formed on the plate (245), limiting the wear to the plate. The stream of material is guided further, along the bed of the same material thus formed, to a rotor (246) which is designed in accordance with the second embodiment (207). After the stream of material comes off the rotatable impact member (220), it is guided further to collision faces (248) of stationary impact members (251), which are fastened around the outside of the rotatable impact members (220), along the wall (250) of the crusher housing (249). The collision faces (248) are curved in accordance with the involute which the stream of material (R) describes from the periphery which the rotatable impact members (220) describe. In the vertical plane, the collision faces (248) can be arranged slightly inclined towards the rear, so that the stream of material (R), which is directed slightly obliquely downwards (252) from the impact face (222), strikes this collision face (248) virtually perpendicularly. Horizontal plates (253) may be fastened along the bottom of these stationary impact members (251). This results in the formation, below and along the front of the involute collision face (248), of a rim (254) on which material accumulates and, therefore, builds up an autogenous bed against the involute collision face (248). This design, which, by making the plates (253) along the bottom of the stationary impact members (251) removable, can be used in accordance with the steel-on-steel principle and the steel- on-stone principle, thus makes it possible largely to protect the collision face (248) from wear, while nevertheless bringing about an intensive working of the material.

Figures 115 and 116 diagrammatically show a fifth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed essentially in accordance with the second embodiment.

The rotor (330) thereof, which has guides (331), is suspended from a disc (332) with a central hole (333). The rotor (330) is situated beneath this central hole (333) in the disc (332).

On its circumference, the disc (332) rests by means of a radial bearing (334) on the casing (335) of the impact crusher. The breaking plates (336) are also attached to this casing.

The annular disc (332) bears a number of wheels (337), the vertical axle (338) of

which is mounted in the disc (332). The axle (338) is also connected to a motor (339). The circumference of each wheel (337) rolls in a supported manner along a running track (340) attached to the inside of the drum (335).

By driving the wheels (337) with the motors (339) in the same direction, a rotational movement of the annular disc (332), and hence of the rotor (330), is generated.

Figure 117 and Figure 118 diagrammatically show a sixth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor (384) being designed essentially in accordance with the third embodiment.

The impact member (320) is designed as a rotating, rotationally symmetrical impact member which is accommodated in a frame (341). This frame (341) is attached to the arm (342). The rotatable impact member (320) comprises a roll (343) with an externally curved surface. This roll (343) is accommodated in a rotatable manner, by means of bearings (344) (345), on an axle (346), both ends of which are accommodated in the frame (341).

The material coming off the guides (347) collides with the surface of the rolls (343).

Since the axial line of the rolls (343) is situated slightly above or below the path of the flung-off material to be broken, the rolls (343) are set in rotation. This results in the broken material being diverted downwards, while in addition the entire surface of each roll (343) is loaded uniformly in the circumferential direction.

Figure 119 and Figure 120 diagrammatically show a seventh embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed essentially in accordance with the third embodiment.

The rotor (349) is equipped with guides (350) and arms (351), to which roll-shaped, rotationally symmetrical impact members (352) with a vertical axis of rotation (353) are attached. Here too, the material to be broken coming off the guides (350) is able to set the rolls (352) in rotation. This results in the material being diverted, for example in the direction of the breaking plates (354). In addition, the entire surface of the rolls (352) is loaded uniformly.

Figure 121 and Figure 122 diagrammatically show an eighth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed essentially in accordance with the third embodiment.

The rotor (355) is equipped with guides (356) and arms (357), to which disc-like impact members (358) with a horizontal axis of rotation (359) are attached. By this means

too, the entire surface of the discs (358) is loaded uniformly.

It is clear that the sixth, seventh and eighth embodiments may also be combined with other embodiments, and this, of course, also applies to the embodiments described previously and subsequently.

Figures 123 and 124 diagrammatically show a ninth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the collision means not being formed by an impact member but by a second part of the material.

In this case, material is flung outwards, from the rotor blade (370) at two different radial distances (r,'/rl"), specifically in such a manner that the streams of grains (361) (362), which are at different velocities, cross one another, with the particles hitting one another.

The first stream of grains (361) is accelerated along a first guide face (363) and the second stream of grains (362) is accelerated along a second guide face (364), the discharge end (365) of the second guide face (364) lying at a radial distance outside that of the first discharge end (366), while the discharge end (365) of the second guide face (364), when seen from a rotating position, is situated behind that of the first discharge end (366). The angle (0') which the two radials (367) (368) form is selected in such a manner that the first stream of grains (361) passes by the outside of the discharge end (365) of the second guide member (364), so that the two streams of grains (361) (362) hit one another at a location (369), at a great radial distance (r,") and when seen in the direction of movement (370), behind the discharge end (365) of the second guide face (364).

After the collision of the two streams of grains (369), the material is taken up in an autogenous ring (361) situated behind it, i. e. a trough structure with the opening directed towards the inside, where an autogenous bed of material is formed.

Figure 125 diagrammatically shows a tenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed in accordance with the principle of the ninth embodiment.

This design is equipped with guide members (372) (373) with different lengths, the short guide members (372) being designed with a straight guide face (374) and the long guide members (373) being disposed tangentially and arranged in the form of a chamber vane (375).

It is possible, according to a second variant of the method of the invention, to allow two or more identical systems to rotate about the same axis of rotation (100).

Figure 126 and Figure 127 diagrammatically show an eleventh embodiment, according to the method of the invention, for a device for breaking granular material or processing it

in some other way.

The design is identical to the second design, but is equipped with two systems (446) (447), which both rotate in the same direction, at the same angular velocity and about the same axis of rotation (O). After it comes off the collision face (448) of the first system (446), which is situated above the second system (447), the material is taken up and guided to the metering face (448) of the second system (447). The radial distances from the axis of rotation (O) to the start and the end of the guide member (449) (450) and the corresponding radial distances (449) (450) to the impact members (453) (454) may be made different for the two systems, in which case it is preferred for the radial distance (450) from the axis of rotation (O) to the rotatable impact member (454) of the second system (447) to be made greater than that (449) of the first system (446), so that the impact in the second system (447) takes place with a greater intensity than in the first system (446).

Figures 128 and 129 diagrammatically show a twelfth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor (389) being designed essentially in accordance with the second embodiment.

In this embodiment, the systems rotate about the same vertically disposed axis of rotation (O), at the same velocity and in the same direction (376). A first part (377) of the material is guided from the first receiving disc (378), via a first guide member (379), to the impact member (380), while the second part (381) of the material is guided from a second receiving disc (382), situated at a lower level, via a second guide member (383), which is positioned directly beneath the first guide member (379), to the same impact member (380). The impact face (384) of the impact member (380) is for this purpose extended downwards, so that both streams of grains (377) (381) hit the same impact face (384). This arrangement has the advantage that the capacity is increased considerably, while the im- pacts of the material against the impact face (384) of the impact member (380) are more spread out.

Both streams of grains (377) (381) are guided from the impact face (384) towards a stationary impact member, which may be designed as a stationary impact segment (385) or as a trough structure (386) in which an autogenous bed (387) of the same material builds up. In addition, a third part (388) of the material may be guided along the front of the bed of autogenous material (387), this third part being hit by material from the first stream of grains (377) and the second stream of grains (381), after which the three streams of grains (377) (381) (388) strike the autogenous bed of the same material (387).

Figure 130 and 131 diagrammatically show a thirteenth embodiment, according to

the method of the invention, for a device for breaking granular material or processing it in some other way.

In this embodiment, the systems (390) (391) are inverted with respect to one another, hence forming a mirror image of one another, the systems rotating about the same axis of rotation (O), at the same angular velocity but in opposite directions. Here too, a first part of the material (392) is guided from a first receiving disc (394), by means of a first guide member (394), to a first impact member (395), and a second part (396) of the material is guided from a second receiving disc (397), by means of a second guide member (398), to a second impact member (399). The method of the invention makes it possible to direct the impact faces of the impact members (395) (399) obliquely towards one another, specifically in such a manner that the paths of the material from the first system (400) and the second system (401), after they respectively come off the first impact member (395) and the second impact member (399), intersect or cross one another at a location (402) which is radially outside the location (403) where the first impact face (395) and the second impact face (399) cross one another. At that location, concentrated collision areas (404) are formed, the number of collision areas (404) corresponding to the total of the number of impact members (395) (399) in the first system (390) and the second system (391). Since the radial velocity of the materials, at the instant at which they hit one another in the collision areas (404), is virtually identical, the streams of material collide with one another at full velocity.

The impulse loading of the collision partners (400) (401) is therefore extremely great while, since the process is autogenous, there is no wear. Since the collision areas (404) are situated at fixed locations radially around the outside of the impact members (395) (399), it is possible to dispose semicircular collection locations (405) radially outside the collision areas (404), in which collection locations semicircular impact faces (406) of the same material build up, which the material then strikes, primarily with the remaining radial velocity compo- nent.

This process also proceeds autogenously, i. e. without significant wear and has a relatively great intensity. It is possible in this process to introduce a third part (407) of the material into the collision area (404) from above, from a stationary feed. This material is then loaded with great intensity by the material streams from the first system (400) and the second system (401). The third stream (407) can then be struck by the first stream (400) and the second stream (401) simultaneously or after the first stream (400) and the second stream (401) have collided with one another. The three streams (400) (401) (407) then together strike the bed of the same material (406). In this way, a very effective collision process is realized, a very great impulse loading being produced with the use of relatively little energy

and limited wear, this loading being distributed evenly over the first part (400), the second part (401) and the third part (407) of the material.

In this thirteenth embodiment, the first system is essentially designed in accordance with the second embodiment and the second system is essentially designed in accordance with the first embodiment.

Figures 132 and 133 diagrammatically show a fourteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed essentially in accordance with the thirteenth embodiment.

This embodiment is essentially identical to the thirteenth embodiment, with the angular velocities of the first system (408) and the second system (409) being oppositely directed but not identical. As a result, the collision areas (404) are not concentrated radially around the outside of the impact members (411) (412), but rather there is a continuous shift, in an area radially around the outside of the impact members (411) (412), of the location (413) where the first portion (414) and the second portion (415) of the material hit one another.

The bed of the same material (416) must therefore be disposed radially around the outside of the locations (413) where the first stream of material (414) and the second stream of material (415) hit one another. This third combination is less effective than the second combination, but is easier to construct. Here too, a third part (417) of the material may be guided in the vertical direction around the collision area (404).

Figure 134 diagrammatically shows a fifteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way.

The material is introduced onto the metering face (418) of a first system (419) and, after it comes off the impact face (420) of this system (419), which is preferably designed in accordance with the thirteenth embodiment, is guided in a direction which is inclined downwards, out of this first system (419), after which the material strikes the impact face (421) of a second system (422), which is disposed beneath the first system (419) and rotates in the opposite direction to, but about the same axis of rotation (O), as the first system (419). After the material comes off the impact face (421) of the second system (422), it is guided in a path to a stationary impact member (423).

Figure 135 and Figure 136 diagrammatically show a sixteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed essentially in accordance with the second embodiment, the rotor (52) being equipped with a preliminary guide member and a

subsequent guide member.

The rotor (255) is similar to the rotor (207) which is described in the second embodiment, but is provided with preliminary guide members (257), which are associated with the guide members (217) and extend from a central inlet (258), which is positioned in the direction of rotation immediately behind the central feed (259) of the guide member (217), in a direction of the central feed (260) of the guide member (261) which follows in the direction of rotation. The preliminary guide face (262) of the preliminary guide member (257) is curved along the natural spiral stream (Sr) which the material describes at that location on the rotor (255), the delivery location (263) of the preliminary guide member (257) lying at a greater radial distance (264) from the axis of rotation (O) than (265) the central inlet (258). Furthermore, a subsequent guide member (264) is disposed on the outside, i. e. in the direction of rotation along the front of the spiral path (S) which the material describes between the guide member (217) and the impact member (220). The aim of the preliminary guide member (257) and the subsequent guide member (264) is to guide the material more effectively along the respective spiral streams (S) (S), and to prevent, at least as far as possible, material from moving along the outside of this stream.

Figure 137 and Figure 138 diagrammatically show a seventeenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed essentially in accordance with the second embodiment, it being possible for the guide members (266) to be disposed at different radial distances from the axis of rotation (O).

The rotor (265) is essentially similar to the rotor (207) which is described in the second embodiment, with the exception of the impact members (220) (267), due to the fact that two impact members (267), which are arranged opposite one another and are fastened to the first rotor blade (211) along the bottom of the outer edge (221), are adjustable, so that they can be disposed at different (268), but, with regard to the balancing, equal radial distances from the axis of rotation (O) by comparison with the other two impact members (220) arranged opposite one another. At the same time, by selecting the guide member (217), the mutually opposite central feeds of the guide members (217) can be disposed at different radial distances (267) (268) from the axis of rotation (O). A rotor (265) of this kind makes it possible to distribute the stream of material which is metered onto the rotor (265) in different quantities to the associated guide members (217) (269), from which guide members (217) (269) the respective streams are guided to rotatable impact members (220) (267), which are disposed at different radial distances (267) (268) from the axis of rotation (O), so that the grains from the respective streams impact at different velocities.

As a result, the different streams are subjected to different loads. This makes it possible to control to a large extent the grain size distribution of the broken material.

Figure 139 and Figure 140 diagrammatically show an eighteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor essentially being designed in accordance with the third embodiment, the guide members (270) being suspended in a hinged manner.

The rotor (271) is essentially similar to the rotor (229) which is described in the third embodiment, with the exception of the guide members (270), which are fastened to the rotor (271) by a vertical hinge (272), at a distance from the axis of rotation (O), the pivot point (273) lying at a shorter distance from the axis of rotation (O) than the mass centre (274) of the pivoting guide member (270). The delivery end (275) of a pivoting guide member (270) of this kind may, in the plane of the rotation, execute a certain level of reciprocating movement (277), under the effect of the varying loading of the stream (Sr) (Sb) of material which is guided along the guide face (276) of the rotatable impact member (270), with the result that the impacts against the impact face (238) of the rotatable impact member (236) are spread to a certain extent, so that a more even wear pattern is obtained on this impact face (238). The magnitude of the reciprocating movement (277) can be controlled by selecting the distance (278) between the axis of rotation (O) and the mass centre (274), the reciprocating movement (277) increasing as this distance is made shorter.

Furthermore, it is possible to limit the reciprocating movement (277) in the respective directions.

Naturally, hinged guides may also be employed in other embodiments.

Figure 141 and Figure 142 diagrammatically show a nineteenth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed essentially in accordance with the first embodiment, which is designed with an S-shaped guide member (280), a jet of air being guided along the impact face (221).

The rotor (279) is essentially similar to the rotor (207) described in the second embodiment, with the exception of the guide members (280), which are designed differently, while air-guidance members (281) are disposed above the impact members (220). The guide members (280) are designed with a central feed (282), which lies as an extension of the spiral movement which the material describes at that location on the rotor (279), which central feed (282) is bent forwards in the direction of rotation and merges seamlessly into a straight guide face (283) which is directed slightly backwards in the direction of rotation, which guide face (283) merges seamlessly into a delivery end (284) which is bent backwards

in the direction of rotation, and specifically is bent so far that this delivery end (284) lies as a"natura"continuation of the spiral path (S) which the material describes between the guide member (280) and the impact member (220). A guide member (280) of this kind means that the material is taken up uniformly by the central feed (282) and is guided in a flowing movement to the guide face (283). Since the guide face (283) is directed slightly backwards, the stream of material (Sr) is directed, but it is not accelerated too much. The material comes off the backwardly bent delivery end (284) in a"natura"manner, and is guided in the intended, essentially deterministic path (S) at a relatively low velocity. Slot- like openings (286) are arranged in the first rotor blade (211), along the front of the impact faces (221) of the rotatable impact members (220), above which openings a tube (287) is arranged, with the opening (302) in the direction of rotation, through which opening (302), during the rotational movement, air is taken up, which air is blown through the slot-like opening (286) at great speed, along the impact face (221) from the top downwards. This achieves the effect that the material, after impact, is moved in a stream which is directed downwards, as far as possible perpendicularly, when seen from a viewpoint which moves together with the impact face (221).

S-shaped guide members, which are preferred in the devices according to the method of the invention, may, of course, also be employed in other embodiments.

Figure 143 andFigure 144 diagrammatically show a twentieth embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, which can be employed in any embodiment.

The rotor (288) comprises two rotor blades (289) (290), which are supported by the same shaft (291) and have the same diameter. The first, upper rotor blade (290) is provided in the centre with an opening (292), through which the material can be metered onto the metering face (293) of the second rotor blade (289). This metering face (293) is designed in the form of an upright cone. Between the rotor blades (289) (290) there are clamped, as it were, four guide members (294) with associated preliminary guide members (295) and subsequent guide members (296) and impact members (297), at respectively greater radial distances from the axis of rotation (O). The two rotor blades (289) (290) are connected to one another by projections (297) (298), which are disposed behind the guide members (294) (298) and impact members (267) (297). Along the edge (299) of the second rotor blade (289), segment-like sections (301) are taken out of the second rotor blade (289) along the front of the impact faces (300), so that the material is not impeded when it is guided out of the rotor (290) from the impact faces (300). The first rotor blade (290) is equipped with air-guidance members (281), as described in the embodiment with the S-

shaped guide members (279).

Figure 145 and Figure 146 diagrammatically show a twenty-first embodiment, according to the method of the invention, for a device for breaking granular material or processing it in some other way, the rotor being designed essentially in accordance with the second embodiment, the rotor being equipped with two rotor blades.

The material is introduced through an opening (210) in the centre of the first, upper rotor blade (211), onto the metering face (213) of a second rotor blade (214), from where, with the aid of a guide member (217), it is guided, from the edge (218) of this second rotor blade (214), along a first spiral stream (S), in the direction of a first rotating impact member (425), which is suspended, at a greater radial distance from the axis of rotation (O) than the edge (218) of the second rotor blade (214), beneath the first rotor blade (211). When the material comes off this first impact member (425), it is guided in a second spiral path (S') in the direction of a second rotating impact member (227), which is attached, at a greater radial distance from the axis of rotation (O) than the first rotating impact member (425), along the bottom edge of the first rotor blade (211), when seen from a viewpoint which moves together with the said rotating impact members (425) (227). After the material comes off this second rotating impact member (227), the material is guided in a straight path (R) towards the stationary impact member (224), when seen from a stationary viewpoint.

Figure 147 shows a device in the form of a crusher housing (531), in which there is disposed a rotating system which is driven by means of V-belts (533) using an electric motor (532). Figure 148 shows another arrangement in a crusher housing (534), the rotating systems being driven by an electric motor (535) which is directly connected to the axle (536).

In the breaking chambers (531) (534), it is possible to work under atmospheric conditions and at normal temperatures. If the material being processed produces a large amount of dust, it is preferred to employ a limited pressure reduction in the breaking chamber by extracting air at the location of the outlet (537). It is also possible to create a partial vacuum in the breaking chambers (531) (534), making it possible to process and produce ultrafine material. It is also possible in this process to create a low temperature in the breaking chambers (531) (534), by means of an injection of, for example, liquid nitrogen, thus making the material to be broken more brittle, as a result of which it breaks more easily.

The method of the invention thus permits direct multiple impulse loading of a stream of material with great intensity and in an essentially deterministic manner. Due to the fixed location of the impact face, with respect to the fixed location where the grains leave (are

"launched"from) the guide member at a predetermined take-off angle (a) and at a take-off velocity (vab5) which can be selected with the aid of the angular velocity (#), and the fact that the spiral path which the particle describes between the guide member and the impact member is not affected by the angular velocity (Q), it is always ensured that all the partic- les hit the said impact face uniformly : the particles which leave the guide member one after the other are mostly hit by the impact face one after the other, at virtually the same hit point (T), at a velocity (V ) which can be selected with the aid of the angular velocity (Q) and at virtually the same angle (p).

We are thus dealing with an essentially deterministic process, the stream of material leaving the guide member : at a predetermined take-off angle (a) ; at a predetermined take-off location (W) ; at a take-off velocity (Vabs) which can be selected with the aid of the angular velocity after which the stream of material strikes the impact member : at a predetermined impact angle (p) ; at a predetermined impact location (T) ; at an impact velocity (Vhnpac) which can be selected with the aid of the angular velocity (# (Q) ; after which the material is guided in an essentially deterministic, straight path and, without the need to provide extra energy, strikes the collision face of a stationary impact member : at an essentially predetermined impact angle ; at a collision velocity (VCO"jSjon) which is at least as great as the impact velocity (Vim- All the devices and components of devices shown may be employed, as well as for breaking and comminuting materials, also, in the form indicated or in components of the form indicated, for other purposes.

The method of the invention thus makes it possible to allow a material, in the form of separate grains and particles, a stream of grains and particles, optionally a plurality of streams of grains and particles, but also liquid in the form of drops or a stream and mixtures of grains, particles and liquid, to strike an impact member with high accuracy, at a defined angle and at a defined location, it being possible to control the impact velocity accurately, within very wide limits, with the aid of the angular velocity. The method of the invention

is also suitable for collision processes in which materials such as beans, cereals, nuts and the like are involved.

The method of the invention is therefore eminently suitable for breaking granular and particulate material in an essentially deterministic manner, it being possible to make opti- mum use of the high residual velocity (V midual) which the material still possesses when it comes off the impact face. The method of the invention makes it possible to control the level of comminution as well as the grain size distribution of the broken product accurately and within very wide limits while nevertheless achieving a high capacity ; on the other hand, the intensity of the impulse loading can be increased considerably, with the object of pulverizing material as finely as possible. In a chamber in which a partial vacuum prevails, the method of the invention is eminently suitable for comminuting particles to an extremely great fineness, in which case it is possible to produce relatively great amounts (capacity) of extremely fine material.

The high level of determinism of the comminution process makes it possible to load material in a virtually identical manner each time. This makes the method of the invention eminently suitable for the comminution of material (samples of material) which are involved in a laboratory experiment.

By making use of the rebound behaviour of the material, which is determined by the coefficients of restitution of the collision partners, the method of the invention can be used in a simple manner to sort a stream of granular material on the basis of its rebound behaviour or its elasticity. It is also possible to separate a stream of material on the basis of its hardness with great accuracy, i. e. on the basis of that portion of the stream of material which does not break and does break under a specific impulse loading (impact velocity V ).

Furthermore, the method of the invention is suitable for treating the surface of granular material. Possible examples here are the removal of deposits of material of a different sort which has become attached to the surface of grains. A particularly advantageous application is that of allowing the material, with the aid of the residual velocity (Vresjdual) to strike a bed of the same material, thus resulting in an intensive treatment of the grains and a high level of cubicity of the broken product without essentially having to add extra energy to the comminution process.

The method of the invention is also suitable for bringing a stream of material to speed, for example for the purpose of sand-blasting. Furthermore, it is possible to process (comminute) a plurality of types of material simultaneously, in which process these materials become mixed intensively.

Furthermore, the method of the invention makes it possible to test and investigate

material for hardness, in which case it is possible accurately to study the breaking behaviour.

The impact of the material against an impact face can be established with the aid of a high- speed camera. In this case, it is also possible to investigate the air resistance which a material undergoes. It is possible here to subject a material, during a specific time, optionally with intervals, to changing loads (impact velocities) using changing quantities and types of material.

On the other hand, it is possible to investigate and test not the impacting material but (also) the material which the accelerated material strikes. Consideration may be given here to the performance of a material under impact loading from grains and particles, such as dust and hail, drops, such as rain, but also the impact of liquids. The investigation may in this case be directed at the surface, but also at the failure of sheet material ; or else it is possible to investigate the load which is required to make a hole in a material. The testing may be directed either at a disc or plate or at an object. Thus the influence which the shape has on the performance of material or an object can be investigated.

The method of the invention is also suitable for accurately working an object, which then, as it were, functions as an impact member. Consideration may be given here to treating a surface, for example cleaning this surface by means of blasting, but also to treating an object, for example a weld seam, in a targeted manner. This object may move during the treatment process, for example by means of self-rotation, in which case the impact velocity and the quantity and type of material which strike the object can be controlled systematically.

Also, an object or metal can be deformed accurately along the surface by means of impact loading, for example with the aim of prestressing the material or object along its surface.

The method of the invention even makes it possible to move an object in a spiral path and to allow it to strike accurately against another object or material ; the influence of the shape of the two collision partners can thus be included in the investigation. It is even possible here to simulate the impact of a material against an object, or of an object against an object.

Naturally, all the application areas indicated are possible both under atmospheric conditions and in a chamber in which a partial vacuum prevails, at high or low temperature, and under excess pressure. Naturally, combinations of these are also possible.

The following notations have been used in the text and are explained as follows.

0 = included angle between the radial line on which is situated the location (W) where the said as yet uncollided stream of material (S) leaves (r,) the said guide member and the radial line on which is situated the location (T) where the said as yet uncollided stream of

material (S) strikes the rotating impact member (r), when seen from a viewpoint which moves along and on the understanding that a negative value of this angle (0) indicates a rotation in the opposite direction to the rotation of the said guide member. p = the said included angle of impact with the said impact face, at the location where the said as yet uncollided stream of material hits the said impact face, when seen from a viewpoint which moves together with the said rotating impact member.

P'= the said included angle with the said impact face, at the location where the said as yet uncollided stream of material hits the said impact face, when seen in the plane of the rotation, and when seen from a viewpoint which moves together with the said rotating impact member, forms with the line which is directed perpendicular to the said radial line on which is situated the location where the said as yet uncollided stream of material leaves the said guide member p"= the said included angle of impact with the said impact face, when seen in the plane of the rotation, at the location where the said as yet uncollided stream of material hits the said impact face, when seen from a viewpoint which moves together with the said rotating impact member. p'"= the said included angle of impact with the said impact face, when seen from the plane directed perpendicular to the plane of rotation, at the location where the said as yet uncollided stream of material hits the said impact face, when seen from a viewpoint which moves together with the said rotating impact member.

Vre, = relative velocity of the movement of the stream of material, when seen from a viewpoint which moves together with the said rotating impact member V = relative velocity at which the said as yet uncollided stream of material strikes the said impact face, when seen from a viewpoint which moves together with the said rotating impact member vab5 = absolute velocity of the said as yet uncollided stream of material on leaving the said guide member, when seen from a stationary viewpoint vr = radial velocity component of the absolute velocity (v) v, = transverse velocity component of the absolute velocity (vau5) v't = transverse velocity component of the absolute velocity (vars) at a greater radial distance from the axis of rotation than the location where the stream of material leaves the guide member v'r = radial velocity component of the absolute velocity (vars) at a greater radial distance from the axis of rotation than the location where the stream of material leaves the guide member

Vr = radial velocity component of the relative velocity (vire,) at the moment at which the stream of material leaves the guide member and is equal to v V'r = radial velocity component of the relative velocity (Vre,) at a greater radial distance from the axis of rotation than the location at which the stream of material leaves the guide member and is equal to ver V"r = radial velocity component of the relative velocity (Vre,) at a radial distance from the axis of rotation where the relative velocity (Vre,) of the stream of material is equal to vab5 vtt = relative transverse velocity component of the relative velocity (V) at a greater radial distance from the axis of rotation than the location where the stream of material leaves the guide member v = peripheral velocity of the said location where the said as yet uncollided stream of material leaves the said guide member (tip velocity) V', ip = peripheral velocity of the said location where the said collided material is situated after it leaves the said guide member (relative tip velocity), when seen from a viewpoint which rotates together with the said rotating impact member r = the radial distance from the said axis of rotation to the location where the said stream of the said as yet uncollided material and the path of the said rotating impact member intersect one another rl = the radial distance from the said axis of rotation to the location where the said as yet uncollided stream of material leaves the said guide member ro = the radial distance from the axis of rotation to the location where the central feed is situated closest to the axis of rotation r = the radial distance from the axis of rotation to the location where the central feed merges into the guide face r = radial component of the said impact velocity ro = transverse component of the said impact velocity a = the included angle between, on the one hand, the velocity of the location where the said as yet uncollided stream of material leaves the said guide member (tip velocity), equal in size to the product of the angular velocity (Q) and the radial distance from the said axis of rotation to the location where the said as yet uncollided material leaves (rl) the said guide member, and, on the other hand, the absolute velocity (vab5) of the said as yet uncollided stream of material on leaving the said guide member ao = the included angle between the radial line on which is situated the location where the stream of material leaves the guide member and the movement of the stream of material at the moment at which it leaves the guide member.

(p = the angle between the said radial line on which is situated the location where the said as yet uncollided stream of material leaves the said guide member (the said tip of the said guide member), when seen from a stationary position at the moment at which the said as yet uncollided stream of material leaves the said guide member, and the radial line to the location where the said as yet uncollided material hits the said rotating impact member for the first time, when seen from a stationary position f = the ratio of, on the one hand, the magnitude of the velocity of the location on the guide member where the said as yet uncollided stream of material leaves the said guide member (tip velocity) and, on the other hand, the magnitude of the component of the absolute velocity (vau5) of the said as yet uncollided stream of material parallel to the tip velocity, i. e. the product of cos (a) and the magnitude of the absolute velocity (vau5) on leaving the said guide member p = the path covered by the said as yet uncollided stream of material from the said location where the said as yet uncollided stream of material leaves the said guide member to the said location where the said as yet uncollided stream of material strikes the said rotating impact member tc = minimum length of the central feed, which is given as the difference between the radial distance from the axis of rotation (ro) to the location where the central feed is situated closest to the axis of rotation and the radial distance from the axis of rotation (rc) to the location where the central feed merges into the guide face 9 = the minimum length of the guide face, which is given as the difference between the radial distance from the axis of rotation (rc) to the location where the central feed merges into the guide face and the radial distance from the axis of rotation to the location where the guide face merges into the delivery end X = the angle between the radial line on which is situated the location where the central feed is situated closest to the axis of rotation and the radial line on which is situated the location where the material hits the guide member which follows in the direction of rotation Va = the radial velocity component of the grain on the rotor at a radial distance (ro) from the axis of rotation where the central feed is situated closest to the axis of rotation Q = the angular velocity of the rotor R = the straight stream which the material describes after it comes off the guide member, when seen from a stationary viewpoint Rc = the stream which the material describes on the central part of the rotor before it is taken up by the central feed, when seen from a stationary viewpoint

Rd = the steam which the material describes along the guide member, when seen from a stationary viewpoint S = the spiral stream which the material describes after it comes off the guide member, when seen from a viewpoint which moves together with the said rotating impact member se = the spiral stream which the material describes on the central part of the rotor before it is taken up by the central feed, when seen from a viewpoint which moves together with the said impact member Sd = the stream which the material describes along the guide member, when seen from a viewpoint which moves together with the rotating member K = the angle between the radial line on which is situated the location where the central feed is situated closest to the axis of rotation and the radial line on which is situated the location where the material leaves the guide member t = the angle on which are situated the radial lines to the locations on the delivery end, where the material leaves the pivoting guide member, which are situated furthest forwards and furthest backwards in the direction of rotation. tw = the tangent or contact line on the circumference which is described by the location where the material leaves the guide member C = the path which the rotating impact member describes e = the angle at which the layers, which are stacked on top of one another, of a guide member are disposed with respect to the plane of the rotation D'= the diameter of the granular material It will be apparent to those skilled in the art that various changes in the structure and relative arrangement of parts may be made without necessarily departing from the scope of the present invention as defined in the claims appended.