DESCRIPTION Technical Field The present invention relates to an injection nozzle suitable to inject material to be processed inside a mold, particularly, although not exclusively, material to be recycled or post-use material, such as for example heterogeneous plastics or polymer blends from the urban separate waste collection or from industrial wastes.

The present invention also relates to a device suitable to extract gases contained in a material to be injected inside a mold, particularly, although not exclusively, material to be recycled or post-use material, such as for example heterogeneous plastics or polymer blends from the urban separate waste collection or from industrial wastes.

According to a further aspect, the present invention relates to an injection plant suitable to inject material to be processed inside a mould, particularly, although not exclusively, plastic material to be recycled or post-use material, such as for example heterogeneous plastics or polymer blends from the urban separate waste collection or from industrial wastes, and a related functioning method. State of the Art Currently, the collection of the post-use plastic, i.e. plastic coming from the urban separate waste collection or from industrial wastes, is mainly performed through collecting means of public entities, which also carry out the disposal thereof in landfills, incinerators, or for producing fuel.

In particular, wastes from industrial processes, if not re-used in small percentages in the same processes, are collected in landfill, with high disposal costs.

Some forms of re-use are arranged through expensive treatments of selection, milling, washing, centrifugation, drying and conversion, wherein the plastic waste is reduced into fractions of mono-material to restrict the presence of impurities to small percentages. The recycle of post-use plastics can be generally divided in two different sectors: (1) the recycle of homogeneous plastics and (2) the recycle of heterogeneous plastics.

"Homogeneous plastics" means in general the plastics presenting a uniform composition or blend, with impurities (i.e. heterogeneous polymers, phases of inerts, gaseous emissions or other) in limited quantities, usually from approximately 1% to approximately 5% of the total mass.

"Heterogeneous plastics" means a blend of polymeric materials with significant presence of inert and gaseous phases, such as for example the materials from the selection platforms of the urban waste collection or from the wastes of industrial processes.

Nowadays, in the field of waste recycling, heterogeneity is not intended totally, i.e. related to all the types of polymers in any condition and percentage, but to at least 50% or 60% polyolefin based polymer matrices, with the remaining part being formed by PS, EPS, PA, PET, ABS and various inerts, such as small metallic parts, paper, rags, wood, organic material, soil, etc.

The recycling techniques used for the homogeneous plastics are, for the most part, the same as those used for the virgin plastics, in case of both molding and extrusion, and, briefly, the phases characterizing these processes are the following: selection, milling, washing, centrifugation, drying and conversion.

These phases are called pre-treatment phases, and are performed using complex and very expensive plants, that however simplify the final conversion, as they allow to make the material, from which the finished product will be obtained, more uniform. In particular, these pre-treatment phases consist in recreating the thermal and pressure conditions so as to repeat the conversion process in a manner similar to that used for the virgin plastics.

According to the field of reuse, the impurities in the homogeneous plastics to be processed must be absolutely restricted to more or less stable limits. Greater deviations significantly reduce the price of these materials and the quality of the finished product.

Methods and plants for reuse or recycle have been studied also for the heterogeneous plastics. However, only a small percentage of these materials can be successfully recycled, and only at high costs, due to the complex problems caused by the heterogeneity of the polymer fractions, the fractions of various inerts and the high gaseous emissions.

For example, heterogeneous plastics have a high degree of incompatibility, i.e. the polymer phases tend to remain separate from each other as greater the interfacial tension and the dimensions of the particles, according to their mixing and dispersion ability. Furthermore the gases, if not adequately eliminated, increase the interfacial inconsistency between the particles, thus reducing the aggregation ability of the mass.

The mixing is also affected by the different molecular viscosity of the polymers, that avoids deformability of the particles, reduction and fractioning, and therefore various morphological forms of dispersion occur, for example point-like, lamellar, lined and variegated.

The chemical bonds allowing high cohesion between the particles, even after heating, are almost non-existent due to the incompatibility, the melt is generally inconsistent, without capability of elongation, frays and defibers easily, is porous and heterogeneous on the surface, and the mass inside has at least 30% - 40% of porosity, due to the reduced forces of molecular cohesion.

Moreover, it is difficult to intimately homogenize the polymer particles, as well as the inert phases, as they must be dimensionally reduced so as to disperse them in a uniform manner in the melt, affected by the effect of the structural difference and of the viscosity.

It is also difficult to obtain flowing paths in the injection plant that are sufficiently wide for the passage of small inert bodies in order to avoid occlusions; the bulk dimensions are great. The conversion and molding process for the reuse of post-use heterogeneous plastics (similarly to the techniques used for the conversion of the homogeneous materials) in general provides for a sequence of physical-mechanical actions, which is aimed at pre-treating the material, homogenizing it and freeing it from the high gaseous emissions, injecting and mechanically compacting it, in order to obtain the required mechanical and thermal properties.

Nowadays there is practically a wide range of additives greatly allowing to modify the characteristic of the base and the rheological features of the melt, and thus the performances of the finished product, such as for example plasticizers, reinforcers, impact modifiers, cross linkers, stabilizers, lubricants, flame retarders, smoke suppressors, conductors, pigments, color additives, adhesion promoters, wear resistant additives, antioxidants, light-stabilizers, antiblocking agents.

However, the use of the additives entails numerous problems, as heterogeneous plastics are in general low compatible, and therefore low miscible to each other; the additives must be for example dispersed in a uniform manner and adhere to the mass, or it is often necessary, in order to use an additive that determines a characteristic, to also provide another additive to promote the adhesion of the first one.

Melt injection technique can be used for molding, providing an extruder that directly injects inside the mold, or providing an extruder that loads an accumulator head which, in turn, injects the product inside the mold from a single injection point or injection hole.

Some disadvantages of the traditional equipments and machines for recycling heterogeneous plastics are due to the fact that they have low applicability to the production of consumer goods and need prolonged down times and to the fact that the finished products present low quality.

Furthermore, in order to increase the quality of the processing and of the finished product, the heterogeneous material shall be selected and treated through synthesis or selection processes that allow to obtain intermediate compounds that are more workable through a sequence of consecutive chemical reactions. These synthesis processes are long-lasting and laborious, increase the production cost and generate significant scraps.

A further disadvantage of the known molding techniques is that, in the preparation treatment of the materials, they generally don't take into account the gaseous emissions, which can be released in the material under processing in a non uniform and abrupt manner during transformation and injection, so that the structure of the finished product results fragile, with low mechanical resistance and therefore of low quality. Finished products deriving from heterogeneous material are generally produced for technological sectors where particular performances and resistance are not required.

A further disadvantage is the fact that the centralized injection causes rough molding, with great heterogeneity of mechanical resistance from the centre to the edge, inconstancy in filling, a fragile structure at the external edges farthest from the injection centre of the mold. Furthermore, the feedhead is rough, and a further phase must be hence provided, wherein skilled personnel shall cut the burrs manually; consequently, the costs increase, the external surface is rough, the structure is greatly plastic and with low E-modulus, as the thickness is at least four times greater, not very compacted and the cooling is therefore slow. A further disadvantage is that, when the injection is performed directly from the extruder, the production capacity decreases, as the cooling phase must be carried out while keeping the mold closed.

A further disadvantage is that, in order to have a good production yield, it is necessary that the homogenization process is as continuous and uniform as possible, without substantial alterations in the pressure during processing.

Currently, despite the technological developments, it is therefore difficult, and there is a need, to provide molding plants that are simpler and not so expensive to be constructed and used, and that allow at the same time to obtain finished products of good quality.

Summary of the Invention

An object of an embodiment of the present invention is to provide an injection nozzle for a molding plant that is improved over the current ones.

These objects and advantages are substantially obtained with an injection nozzle as claimed in claim 1.

In the present invention and in the attached claims, "material to be treated or molded" means mainly a blend of heterogeneous plastics, post-use or to be recycled, substantially from the urban separate waste collection or from wastes of industrial processes; it is also possible to process any other type of moldable material, for example a homogeneous plastic blend, also in combination with these heterogeneous plastic blends.

In particular, post-use heterogeneous plastics can comprise polymers suitable to be reused through injection and molding in percentages greater than 55% of the overall mass of the material, and can be at least some of the following: PELD, PEHD-PS-ABS, PA-PET-PP and derivatives thereof, polylaminates and pulper, acetate, polycarbonate, methacrilate only in percentages lower than 5% as well as inerts such as loam, metal residues, rags, paper and wood in proportion within 10% in weight, polylaminates and blends of materials from collection areas.

The base polymer blend has preferably highly viscous-elastic characteristics, suitable to act as a binder and to aggregate the other polymers and inerts disseminated more or less finely in the blend, even if not completely melt.

The polymers of the type PEHD, PELD and PP have a good degree of affinity (polyolefins) able to construct, with their viscous-elastic properties, the binder suitable physically to join stably the polymer particles and the inerts forming the - - blend, defined usually "property of interfacial bond" of the particles.

The minimum quantity of binder necessary for the polymer blend to have the suitable mechanical characteristics is preferably not lower than 55%-60%.

According to a first aspect, the present invention relates to an injection nozzle with an exit hole to inject a material in a mold through an injection hole. The nozzle comprises a coupling end or coupling member suitable to move so as to open or close at least the exit hole and to engage or release a closing element in the injection hole.

In a particularly advantageous embodiment of the present invention, the closing element can be engaged in the injection hole by means of a reversible blocking system, such as for example a snap blocking system that can be actuated through a slight forcing during the movement of the nozzle towards the injection hole.

Advantageously, the coupling end or coupling member and the closing element engage to one another by means of a controlled coupling system, comprising for example a shaped end or bayonet, provided on the coupling member, that can be inserted by rotation in a shaped aperture provided on the closing element, or vice versa.

In a particularly advantageous embodiment, at least one first handling system is provided, to actuate the coupling system, and at least one second handling system is provided to actuate the blocking system.

In the preferred embodiment, the above mentioned first and second handling systems include a single oleodynamic device that is advantageously and preferably actuated by a single electronically controlled four-way valve, which feeds a first inlet and a second inlet. The nozzle is preferably of the type comprising a first outer sleeve with a heat- resistant ring, so as to reduce the heat exchange with the mold, and a second inner sleeve, within which the material to be processed flows.

The inner sleeve advantageously comprises a hot-spot heating system with independent thermal control, so as to avoid cooling and solidification of the material to be processed which can be still present inside the nozzle after the injection phase.

In a particularly advantageous embodiment, the coupling member is associated with the end of a rod arranged inside the second sleeve, so as to obtain a device which is particularly simple to construct and use. It is also possible to design the coupling member in other manners, according to particular construction or use requirements.

In this way it is possible to close both the exit hole of the nozzle and the injection hole of the mold with a single control device (the electronically controlled four- way valve), thus increasing the profitability and the functionality of the process. Furthermore, the nozzle and the mold are independent, so as to allow to load new material to be injected inside the nozzle and at the same time to detach the filled mold from the nozzle.

Definitely, these measures allow easily to decrease the molding times, and thus to increase the production and at the same time to increase the conversion continuity and the homogenization of the plant.

In an advantageous embodiment, the nozzle comprises a first tilting system, suitable to make the nozzle oscillate or basculate angularly and axially for tight connection in the injection hole, and a second tilting system, suitable to make at least the rod oscillate or basculate angularly and axially relative to the body of the nozzle for insertion of the closing element in the same injection hole, so as to offset any small deviation or clearance. An advantage of this embodiment is that the above mentioned first and second tilting systems allow small angular and axial adjustments, so as to allow both a better sealing between the nozzle and the injection hole of the mold and an easier closing of the injection hole by means of the closing element, even if small angular differences or differences in reciprocal positioning occur, and this also for more nozzles composing the injection equipment.

The first tilting system can include a series of elastic elements interposed in blocking clamps of the nozzle and the second tilting system can include suitable joints arranged on the rod. It is clear that different tilting systems can be provided, according to particular construction or use requirements.

In the preferable embodiment, the nozzle has a wide passage aperture (i.e. an inner sleeve with great diameter) and the exit hole and the injection hole suitable to the passage of small inert bodies, particularly suitable to the injection of post-use heterogeneous plastics. It is also possible to use this nozzle also to inject different types of material to be processed, such as for example homogeneous plastic material, virgin plastic material, or other. In this case, the passage aperture and the exit and injection hole can have a smaller cross section.

In a further embodiment of the present invention, the seal between the nozzle and the mold in obtained by adequately shaping the contact surfaces, without the - o - need for rubber gaskets.

An advantage of some embodiments of the injection nozzle according to the present invention is that it is particularly simple and economical in production and use, as it is composed by few elements which can be easily constructed and assembled, and at the same time it is greatly efficient and effective, in particular to inject post-use heterogeneous plastics, but not only. Furthermore, a nozzle of this type can be easily interchanged and extracted from its support, thus facilitating maintenance operations. It is in fact possible to demount the nozzle from its seat in a very fast manner with a short production interruption. Further advantages of some embodiments of the present invention are that this nozzle allows a particularly efficient and fast injection phase, avoids thermal non- uniformities, avoids the extrusion of the material but at the same time allows the exit of at least a part of the gaseous emissions, and it has low load losses, thus allowing net injection pressures on the injected material that are low but sufficient to generate stable interfacial bonds between the base blend (polyolefin blend) and any other component.

A further advantage of some embodiments of the nozzle according to the present invention is that most of the seals can be of mechanical type, therefore without flexible rubber gaskets that can deteriorate or damage. In fact, the melt material is generally a fluid of non-newtonian type and therefore with laminar layers in the order of some hundredths of millimeter that are suitable not to flow out from these seals, but that at the same time allow at least partially the leakage of the gaseous and liquid emissions which have significantly greater flowability.

According to another aspect, the invention relates to a method for injecting material into a mold through one or more injection holes by means of one or more nozzles of the type defined above, which provides for at least the following steps in sequence: moving each nozzle towards the respective injection hole closed by a closing element; opening the injection hole; injecting the material into the mold through the injection hole or holes by means of the nozzle or nozzles; closing the injection hole or holes; moving the nozzle or the nozzles away from the mold; cooling the mold after the injection; opening the mold and removing the finished product after cooling.

In some embodiments of the present invention, the steps of moving towards the nozzles, opening the injection holes, injecting the material, closing the injection holes and moving away the nozzles are performed in the same injection station.

An object of a further embodiment of the present invention is to provide a device suitable to extract, at least for the most part, the gases contained in a mass of material to be injected into a mold, in particular when the polymers are heterogeneous and include inert phases. According to one aspect, the present invention relates to a degasser for extracting the gases contained in the material to be processed flowing inside a work chamber, comprising at least one inlet for the material under processing in said work chamber; an exit for the material under processing from said work chamber; a motorized feeding rotor to transfer the material from the inlet to the outlet; an upper aperture for extracting the gases and at least one crushing element associated with the aperture so as to crush the material under processing in order to extract most of the gases. (60%-70%)

Advantageously, the rotor has a shaped cylindrical surface, suitable to transfer the material during the rotation, which for example includes a plurality of projections or toothings sweetly joined to each other.

In an advantageous embodiment of the present invention, the crushing element is provided with at least one roller covered by a plastic, antiadherent, high temperature resistant material, with a low friction coefficient, such as Teflon, and hinged on a movable supporting arm, to press or crush the material under processing. It is also possible that this crushing element is of a different type and/or that more crushing elements are provided, combined to each other, also according to particular construction or use requirements.

A particularly advantageous embodiment provides one or more scraping elements suitable to remain constantly spaced from the shaped surface of the rotor so as to separate the inlet and the outlet of the degassing device. If this is arranged between a plastification chamber and an injection chamber of the plant, the two chambers can be therefore maintained reciprocally separated, so as to reduce reciprocal effects, due to differences in the pressure in the two chambers.

In this way it is possible to avoid or substantially to limit that the variable injection conditions (from 30 to 150 bar) affect the pressure and temperature conditions of an homogenization unit (extruder).

The degasser according to the present invention, therefore, avoids that during injection at the maximum pressure, the melt material flows back from the cylinder of the extruder. . _

The scraping element is advantageously and preferably actuated by a handling mechanism, so as to avoid the contact and the direct stripping between the scraping element and the surface of the rotor. The handling mechanism can be of any type suitable to the purpose, preferably a cam mechanism, hi other embodiments of the present invention the handling mechanism can comprise a fluid-dynamic actuator or other. hi the preferable embodiment, a motorization is provided for rotating the rotor with an electronically controlled rotation speed, so as to maintain the pressure of the material substantially constant inside the work chamber. An advantage of some embodiments of the degasser according to the present invention is that it allows to extract the most part of the gas contained inside the material to be processed in a very effective manner.

Another advantage of some embodiments of the present invention is that said degasser allows to maintain the upstream area, where an extruder can be provided, separated from the downstream area, where the injection system is provided, so that, by arranging the degasser between the extruder and the injection area, it is possible to actuate contemporaneously the extruder and the injection group without interruptions and without reciprocal interactions.

An advantage of some embodiments of the present invention is that it is possible to maintain the flow rate of the material quite constant, absorbing any variation thereof and making the degassing process continuous and uniform without substantial alterations of the pressure during processing.

In particular, by providing the motor with variable revolutions applied to the rotor, the homogeneity and the uniformity of the material under process increase, as the greater speed of rotation allows a greater fractionation of the material, and therefore a greater activity of degasification on thinner layers.

It is also possible to control the packing pressure of the material, also according to the viscosity degree thereof, so as to obtain a high mechanical quality and a better aesthetical aspect of the finished product. A further advantage is that said degasser can be inserted in any transformation process or in any regrinding line for processing heterogeneous plastics.

According to a further aspect, the present invention relates to an injection plant comprising at least one injection equipment with a plurality of nozzles to inject a material through respective injection holes of the mold. In a particularly advantageous embodiment of the present invention, this plant comprises a heated feeding chamber, suitable to feed the nozzles of the injection equipment in a substantially continuous and advantageously quite uniform manner. It also comprises wide flowing channels to avoid obstructions by the inert particles present in the material depending upon the type and the shape of the product to be molded and the viscosity of the material to be processed.

In some particularly advantageous embodiments, the plant according to the present invention comprises a track or path with at least the following working stations actuatable contemporaneously so as to work with a plurality of molds at the same time: an injection station, suitable to open one or more injection holes of the mold, to inject the material into the mold through these injection holes and to close the injection holes; a cooling station, suitable to cool the mold after the injection; an ejecting station, suitable to open the mold to extract the finished product after cooling. In particular, the injection station and the nozzles comprise wide flowing channels for the material to be injected, so as to avoid obstructions by the inert particles present in the material in order to facilitate the injection of the post-use material to be recycled.

According to some advantageous embodiments of the present invention, an extruder is provided, for feeding or injecting the material in the injection station, as well as a compensation mechanical joint between the extruder and said station in order to offset the axial expansions due to the heating of the extruder.

In this way it is possible to inject a post-use heterogeneous material even if high quantities of gaseous phases, humidity and solvents are present, as well as in the presence of paper, volatile substances emitted by the polymers of the material, fermentation and evaporation of sewage, solid inert elements, such as for example metallic traces, even in laminar form.

According to another aspect, the present invention relates to a method to inject a material into a mold through a plurality of injection holes by means of a plurality of nozzles in a plant of the type defined above, which provides for at least the following steps in sequence: moving each nozzle towards the respective injection hole closed by a closing element; opening the injection holes; injecting the material in the mold through the injection holes by means of the nozzles; closing the injection holes; moving the nozzles away from the mold; cooling the mold after injection; opening the mold and removing the finished product after cooling.

In some embodiments of the present invention, the steps of moving towards the nozzles, opening the injection holes, injecting the material, closing the injection holes and moving away the nozzles are performed in the same injection station. In an advantageous embodiment of the present invention, a cooling station, for cooling the material, and an ejection station, for opening the mold and ejecting the finished product, are provided. The injection station, the cooling station and the ejecting station are actuated so as to work a plurality of molds substantially at the same time. For example, whilst a mold is in the injection station, to inject the plastic material inside it, a second mold is in the cooling station and a third mold is in the ejecting station. In this way the working time decreases and the production rate increases.

Further advantageous characteristics and embodiments of the method and of the device according to the present invention are set forth in the appendent dependent claims and will be further described hereunder with reference to some non-limiting embodiments provided by way of example. Brief description of the drawings

The present invention can be better understood and its numerous objects and advantages shall be more apparent to those skilled in the art with reference to the accompanying schematic drawings, which show a non-limiting practical embodiment of the invention. In the drawing: figures 1 to 7 show partially cross sectional side views of working steps of an injection nozzle according to one embodiment of the present invention; figure IA shows an enlarged exploded view of details of the nozzle of figure 1 according to a particularly advantageous embodiment of the present invention; figure 8 shows a complete side view of the nozzle of figure 1; figure 9 show a partially cross sectional side view of an injection equipment comprising a plurality of nozzles according to figure 8; figure 10 shows a partially cross sectional side view of a degasser according to one embodiment of the present invention; figure 11 shows a sectional top view according to the arrow X-X of figure 9; figure 12 shows an enlarged and sectional detail of the degasser of figure 9; figure 13 shows a partially sectional view according to the arrow XIII-XIII of figure 12; figure 14 schematically shows a side view of an injection and molding plant according to one embodiment of the present invention; figure 15 shows a schematic top view of the plant of figure 14. Detailed Description of some Embodiments of the Invention In the drawings, in which the same reference numbers indicate the same parts in all the figures, number 1 indicates an injection nozzle according to one embodiment of the present invention, see figure 1, comprising a coupling member 3 suitable to engage a closing element or pellet 5 to open an injection hole 7 of a mold 9 or suitable to release it to close the hole 7. In the embodiment shown in figure 1, the nozzle 1 includes an outer sleeve 13 and an inner sleeve 15, between which a heat-resistant ring (made for example in vetronite) can be inserted to reduce the heat exchange with the mold 9, and a hot-spot heating system with independent thermal control, including at least one spiroidal resistor 17 arranged in a adequate seat provided on the outer surface of the inner sleeve 15. In this way it is possible to control the temperature at the end of the nozzle 1 so as to avoid the cooling and solidification of the material to be processed.

Inside the inner sleeve 15, a rod 19 is advantageously arranged, which rod is slidable and rotatable around its own axis Xl, at the lower end of which the coupling member 3 is fixed or arranged. It is also possible to associate the coupling member 3 to the nozzle 1 in other manner according to particular construction requirements.

In some embodiments of the present invention, at the edge of the hole 7 a snap blocking mechanism 21 is provided. In some embodiments, the snap blocking mechanism comprises shaped springs 11 fixed between an inserted seat 7A and a plate 7B, which define the hole 7 and are suitable to reversibly engage the closing element or pallet 5, as will be described in greater detail hereunder with reference to figure IA.

In figure IA a coupling mechanism 20 is shown, to engage the pellet 5 to the coupling member 3, including a bayonet mechanism or tab 3 A (partially visible in the figure) in the same coupling member 3 to enter in a shaped seat 5A provided in the pellet 5 by means of an axial rotation F3 of the rod 19, with which the coupling member 3 is integral.

It is clear that this coupling mechanism 20 is here schematized just by way of example, as it can be of any other type, for example the bayonet 3 A can be provided on the pellet 5 and the shaped seat 5 A can be provided on the coupling member 3, or - - in other manner.

Figure IA also shows the above mentioned snap blocking mechanism 21 to block the pellet 5 inside the hole 7 through the springs 11, which advantageously have an arched shape so as to project partially from the hole 7. Locking screws 7C can serve to lock the springs 11 between the seat 7 A and the plate 7B. The seat 7 A can be screwed on the edge of the hole 7.

The pellet 5 has a shape suitable to enter precisely in the hole 7 to close it, and has lateral grooves 5 S inside which the springs 11 can be inserted to block the pellet 5 by holding it in the hole 7. It is therefore possible to close the mold 9 by means of the pellets or closing elements 5, so that it can be immediately transferred outside an injection station, for cooling, and at the same time to close an exit hole IF of the nozzle 1 by means of the end 3 of the rod 19 so as to allow the immediate recharge of the accumulator head.

It should be noted that the pellet 5 is maintained in a fixed angular position by means of the springs 11, by means of the grooves 5S and by a slight shaping of the hole, if necessary.

In a particularly advantageous embodiment of the present invention, an oleodynamic device 23 is provided, including: a first handling system 25, to move the coupling member 3 towards and away the hole 7 of the mold 9, and a second handling system 27, to lock the closing element or pellet 5 to the coupling member 3 or to release it there from.

In particular, the first handling system 25 comprises preferably a first piston- cylinder actuator, with a piston 25A, slidable in a cylinder or chamber 25B, suitable to move towards or away from the injection hole 7 the coupling member 3, on which the closing element 5 is associated, so as to open or close the injection hole 7 through a slight forcing on the closing element 5 in the hole 7. The second handling system 27 comprises a second piston-cylinder actuator with a piston 27A, slidable in a chamber or cylinder 27B and provided with a mechanical transmission 25E, 27E (for example gear wheel and rack) to the rod 25 A of the first actuator, in order to rotate it around the axis Xl of the coupling member 3, so as to couple the closing element 5 to, or release it from, the coupling member 3. In the illustrated embodiment, the pinion 25E is provided on a shaft 25F, which has a key 25G so that the piston 25A rotates about the axis Xl integrally with the pinion 25E and at the same time it is axially slidable. In this way it is possible to reduce the dimensions of the device. More in particular, the first piston 25A is slidable along the axis Xl (see arrows FIa and FIb) inside the first chamber 25B and is integral with the rod 19, so as to lift or lower it in order to open or close the hole 7 through a slight forcing of the pellet 5 against the springs 11 in the hole 7. The piston 25A is provided on the end of the rod 19 opposite to the end where the coupling member 3 is arranged (see also figure 8). The first chamber 25B is closed at the bottom by a closure 25C and a series of seals 25D.

The second piston 27A is slidable inside the second chamber 27B along the axis X2 (see arrows F2a and F2b) perpendicular and incident relative to the first axis Xl and arranged above the first chamber 25B. The second chamber 27B is closed at the end by a closure 27C and a series of seals 27D.

The pinion - rack system 25E and 27E is shown herein just by way of example, as it can be designed with any other system suitable to the purpose.

Advantageously, the fluid-dynamic device 23 includes ducts 23A, 23B, 23C, 23D, 25F and 27F for feeding pressurized fluid P in order to actuate in sequence the first and the second actuator 25 A, 25B and respectively 27A, 27B.

In particular, a first and second inlet duct 23A and 23B feed alternatively pressurized fluid P in the first chamber 25B or in the second chamber 27B, so as to actuate in sequence the pistons 25 A and 27 A, and a lower outlet duct 23 C and an upper outlet duct 23D to put the first chamber 25B in fluid connection with the second chamber 27B, see the detailed description below.

More in particular, the first inlet duct 23 A ends in the upper part of the first chamber 25B and the first inlet duct 23B ends in the lower part of the second chamber 27B. Furthermore, the lower outlet duct 23C ends in the first chamber 25B arranged more downstream along the sliding direction F Ia-F Ib of the piston 25 A relative to the end of the upper outlet duct 23D. The same lower outlet duct 23C moreover has an outlet in the second chamber 27B arranged more downstream along the sliding direction Fla-F2b of the piston 27 A relative to the end of the upper outlet duct 23D. Furthermore, on the head of each piston 25 A and 27 A a substantially T-shaped connection duct 25F and respectively 27F is provided, to put into fluid connection the respective chamber 25B or 27B with the outlet ducts 23C or 23D according to the position of the pistons 25A, 27A in the respective chamber 25B, 27B.

In figure 1 entrance holes should be noted, closed by closing screws T, which - - serve for tool-machining the ducts 23 C, 23D.

Advantageously, it is possible to provide only one electronically controlled four-way valve to feed the first and the second inlet 23A and 23B.

The oleo-dynamic device 23 described above is particularly simple, efficient and effective. However, it is also possible to provide a different device suitable for the same purpose according to particular construction and use requirements.

The seal between the nozzle 1 and the mold 9 can be obtained by providing that the respective contact surfaces are slightly inclined, so as to obtained a nearly linear contact. The closing force between them creates therefore a high contact pressure, thus avoiding leakage of melt material in a very easy and effective manner and furthermore avoiding the need for rubber seals which can deteriorate during the use.

Advantageously, the lower head of the pellet 5 can be provided with an antihaderent and thermal insulating layer in Teflon or other adequate material, to obtain an optimum surface quality of the finished product, also in correspondence of the pellet 5.

The lower head can furthermore have a small raised edge - not shown in the figure for the sake of simplicity - to cut any solid inert part which can stop between the exit hole IF of the nozzle 1 and the injection hole 7 of the mold 9, which can cause an incomplete closing of the mold after injection.

In figure IA shaped seats 7S can be seen, provided in the plate 7B and suitable to contain the springs 11 and to allow the deformation thereof so as to obtain the snap blocking.

It is clear that also this snap mechanism 21 is here represented and described merely by way of example as it is particularly simple and effective for the purpose, but it can be designed in any other manner. For example the springs 11 can be of a different type or they can be replaced with a pin or something else.

The functioning of the nozzle 1 is described hereunder with references to figures 1 to 8. It provides for an injection phase (figure 1), wherein the mold 9 is moved to contact the nozzle 1 and the rod 19 is lifted inside the inner sleeve 15 so as to leave open the hole IF of the nozzle and the hole 7 of the mold 9 and to allow the passage of the material M to be molded.

The inner sleeve 15 and the holes IF and 7 can have a large diameter, for example from approximately 22 to approximately 45 millimeters, so as to allow the passage of material M of the post-consumer heterogeneous type, i.e. coming from the separate waste collection or from industrial processes and including solid residues with greater or smaller dimensions, to nearly 6 or 8 millimeters.

Figure 2 shows a phase subsequent to the phase of figure 1, wherein a pressurized fluid P (oil or other) is fed in the first inlet 23 A to gradually lower (arrow

FIa) both the first piston 25 A and the rod 19, until the hole IF of the nozzle is closed by means of the coupling member 3 and the hole 7 of the mold 9 is closed by means of the pellet 5.

In particular, the pressure of the fluid P produces a slight forcing so as to snap insert the springs 11 inside the lateral grooves 5 S of the pellet 5.

The pressurized fluid is fed, arrow P, from the first inlet 23A so as to make the first piston 25 A slide in the upper part of the chamber 25B along the sliding direction

Fl and at the same time to press the fluid present in the lower part of the chamber

25B so as to push it through the ducts 23D and 23C towards the chamber 27B. Once the piston 25 A has achieved the lower end of its run (figure 2), the first chamber 25B is put into fluid communication with the left part (in the drawing) of the second chamber 27B by means of the connection duct 25F provided in the head of the piston

25A which is at the upper outlet duct 23D. The pressurized fluid starts therefore filling the left part of the second chamber 27B so as to displace the piston 27A from the left to the right (in the drawing).

Figure 3 shows how the fluid P, fed in the first inlet 23 A, actuates the displacement of the second piston 27 A (towards the right according to the arrow F2a) in the second chamber 27B to put the first piston 25A into rotation around its own axis Xl (see arrow F3a) by means of the pinion-rack system 25E and 27E. The bayonet 3A (see also figure IA) therefore rotates by 90° to release from the pellet 5, which remains firmly blocked in the hole 7 by means of the snap coupling system 21.

Figure 4 shows a phase subsequent to that shown in figure 3, wherein it should be noted in particular how the mold 9 is lowered (arrow F4a) to remove it from the nozzle 1 ; the plate 5 closes the hole 7 of the mold 9. During this phase the cooling of the material M injected in the mold 9 starts.

It should be noted that in the above mentioned phases the fluid P for actuating the fluid-dynamic device 23 is maintained pressurized.

Figure 5 shows a phase subsequent to that of figure 4, wherein the mold 9 has been replaced with an empty mold 9A which is lifted (see arrow F4b) into contact _ and tight against the nozzle 1. The mold 9 A has a snap coupling system 21 entirely similar to that of the mold 9, and in its hole 7 another pellet 5 is present.

In this phase the bayonet 3A of the coupling member 3 enters inside the shaped seat 5 A of the pellet 5; the fluid P is fed from the inlet 23 A. Figure 6 shows a phase subsequent to that of figure 5, wherein the coupling member 3 couples to the pellet 5 by means of the rotation (arrow F3b) of the rod 19 around the axis Xl. hi particular, in this phase the pressurized fluid P is fed in the second inlet 23 B of the device 23 so as to gradually move the second piston 27A (toward the left according to the arrow F2b) and to put the piston 25 A (see arrow F3b) into rotation around its own axis Xl; the fluid is discharged at low pressure from the inlet 23 A.

In this way the bayonet 3A rotates inside the shaped seat 5A to couple the member 3 to the pellet 5.

Once the second piston 27A has reached the upper end of its run (toward the left in figure 6), the right part (in figure) of the second chamber 27B is put into fluid communication with the lower part (in figure) of the chamber 25B by means of the ducts 27F and 23C.

Figure 7 shows the phase subsequent to that of figure 6, wherein, by continuing feeding the pressurized fluid from the inlet 23B, it is possible to open the holes IF and 7 so as to inject the material M in the mold 9 A.

In particular, the fluid fed from the inlet 23B passes through the ducts 27F and 23 C and enters in the lower part of the chamber 25B to lift gradually both the piston 25A, arrow FIa, and the rod 19 integral thereto. hi a particularly advantageous embodiment of the present invention, the rod 19 comprises two joints 29A and 29B, see figure 8, to form a tilting system 29 suitable to make at least the rod 19 oscillate and basculate longitudinally and axially in order to offset any small clearance or deviation during the insertion of the pellet 5 in the hole IF of the nozzle 1 and in the hole 7 of the mold 9. It is clear that this tilting system 29 can be designed in any other manner according to particular applications. Figure 9 shows an injection equipment 31 comprising a plurality of nozzles 1 centered in respective holes 7 to inject simultaneously the material M in the mold 9. hi this way the injection phase is simplified, as it is possible to inject the material M with a great uniformity in the mold 9, substantially reducing the problems due to the postmold of the material during the cooling of the mold. In some embodiments, the injection equipment 31 comprises an upper plate 33 and a lower plate 34 separated by spacers 35, one or more inlet collectors 37 to feed the material M from an accumulator head (not shown in figure for the sake of simplicity) of the plant to a feeding chamber 39. Advantageously, in some embodiments of the present invention on the upper plate 33 the oleo-dynamic devices 23 of each nozzle 1 are fixed, and passage holes F are obtained to feed the pressurized fluid P to each inlet duct 23A and 23B. The lower plate 34 acts as a support for the nozzles 1.

In an advantageous embodiment of the present invention, the feeding chamber 39 is designed so as to receive one or more feeding collectors 37 for the material M and to feed it uniformly and simultaneously to all the nozzles 1 through adequate inner channels (schematically indicated in figure 9 with the number 39C). On the lower surface of the hot chamber or feeding chamber 39, the nozzles 1 are fixed by means of respective tight blocking jaws 41, whilst on the upper surface tight passage holes 39F are provided for the rods 19 of each nozzle 1. A hermetic bush 39B provides this seal.

Advantageously, a further tilting system 42 is provided for each nozzle 1, obtained by interposing to each blocking jaw 41 an elastic element, such as for example a spring 42 A, suitable to be elastically deformed. In this way it is possible to make each nozzle 1 oscillate or basculate angularly and axially, so as to insert it in the respective hole 7 of the mold, offsetting any axial and/or angular positioning error.

It is clear that this second tilting system is described merely by way of example, as it can be designed in any other manner according to particular construction and use requirements.

Figure 10 shows a degasser 50 to extract the gases contained in a mass of material M, moving inside a work chamber 51, which includes an inlet 501 and an outlet 5OU for said material M. Inside the work chamber 51 of the degasser 50 a motorized feeding rotor 53 is arranged to transfer the material M from the inlet 501 towards the outlet 5OU. The chamber furthermore includes an upper aperture 50S for gas discharge.

Two crushing elements 55A, 55B are associated with the aperture 5OS so as to crush the sliding material M to extract at least part of the gases from it. A cover 54 envelops the aperture 50S and the crushing elements 55A, 55B and on it an outlet duct 52 is provided for discharging the extracted gases.

The rotor 53 advantageously has a shaped cylindrical surface with a plurality of projections or toothings sweetly joined to each other to transfer the material M during the rotation, hi some embodiments of the present invention the rotor 53 has a lined lateral surface, i.e. a surface formed by a series of straight lines parallel to each other and to an axis of the rotor, and presents a cross section with a differently shaped profile, defined by a plurality of arcs of circumference, each corresponding to a cylindrical portion with the concavity facing towards the outside of the rotor. The concave cylindrical portions of the lateral surface, which are indicated with Sl, are mutually joined at adequately chamfered or rayed cusps, indicated with S2.

The crushing elements 55A, 55B are preferably formed by respective metallic rollers covered with a plastic, preferably antihaderent, high temperature resistant material with a low friction coefficient, for example Teflon, hinged on support arms

57A and 57B respectively, pushed downward by a thrust system 59A and respectively 59B, for example of the spring type or other.

Advantageously, a first scraping element 61 A is provided at the inlet of the degasser 50 and a second scraping element 6 IB at the outlet thereof, which are maintained constantly spaced from the shaped surface of the rotor 53, avoiding contact and stripping, so as to avoid the accumulation of material M in the lower area of the chamber 51. This accumulation can be dangerous and can damage the degasser.

In order to make the scrapers 61 A and 6 IB remain at a short distance (in the order of some tenths of a millimeter) from the shaped surface of the rotor 53, it is possible to provide a handling mechanism with desmodromic cams or channel, see in particular figures 12 and 13, which controls a tilting movement of the scrapers synchronized with the rotation movement of the rotor 53. Clearly, other types of handling mechanisms are also possible, suitable to the same purpose, see the description below.

In an advantageous embodiment of the present invention, a support shaft 53 S is provided for the rotor 53, at whose end are keyed a wheel 59A and respectively 59B, integral with it and on which a channel cam profile 60 is provided, facing towards the inside, see also figure 13.

Figure 12 shows the enlarged detail according to the line XII-XII of figure 10, wherein in particular a support shaft 61 S should be noted for the scraper 6 IA, at whose ends a rocker arm 63 is keyed, which has a misaligned pin 63 P suitable to slide inside the channel cam 60. In this way, the rotation of the shaft 53 S controls an oscillating movement of the rocker arm 63 and therefore of the shaft 61 S.

Figure 13 shows a partially sectional view according to the line XIII-XIII of figure 12, wherein it should be noted in particular how the pin 63P of the rocker arm 63 slides inside the channel cam 60 of the wheel 59A. A similar mechanism can be provided on the wheel 59B.

Therefore, provided that the path of the cam profile 60 is adequately shaped, it is possible to move the scraper 61 A (or the scraper 61B) so as to maintain it constantly spaced from the shaped surface of the rotor 53. In fact, the wheel 59A rotates integrally with the rotor 53 on the shaft 53 S and the cam 63 puts the shaft 61 S into oscillation with an oscillation motion, and the shaft 61 S in turn brings into oscillation the scraper 61 A. The scraper 61B has an analogous functioning.

It is clearly apparent that the handling mechanism of the scraper 61 A, 6 IB is described and illustrated herein merely by way of example, as it is possible to design it at least partially in a different manner, for example the grooved path 60 could face towards the outside.

According to a different embodiment of the present invention, a handling mechanism is provided with a fluid-dynamic actuator for the scraper 6 IA, 61B alternatively to the cam mechanism described above. In particular, this oleo-dynamic handling mechanism can comprise a sensor suitable to detect the position of the cam and to control the oleo-dynamic actuator, which in turn serves to move the scraper 61A, 61B.

In some embodiments of the present invention a motorization Ml is provided (for example an inverter motor) which can be controlled by an electronic unit El to rotate the rotor 53 with an adjustable rotation speed, so as to maintain a nearly constant flow rate of material M under processing inside the chamber 51 according to the specific work.

Advantageously, is it possible to provide for the electronic unit El to be connected to a transducer - not shown in the figure for the sake of simplicity - to constantly detect the pressure and/or the speed of the material M under processing in the chamber 51.

Figure 11 shows a sectional view according to the line XI-XI of figure 10, wherein it should be noted in particular that both the inlet 501 and the outlet 50U have a section which enlarges and respectively shrinks in a gradual manner, so as to flatten the material M inside the chamber 51, thus facilitating the extraction of the gas contained inside it.

Figures 14 and 15 show a side and plan view of a molding plant 100 according to a particularly advantageous embodiment of the present invention.

In particular, this plant 100 includes two mutually opposite injection lines 70. In some embodiments of the present invention, each injection line 70 comprises at the inlet separation cyclones 71 to perform the separation of the air from the material M, storage silos 73 for mixing and dosing the material M and the additives, a hopper 75 for forced feeding of the material M, a screw extruder 77 with a motor 77M for mixing and move forwards the material M, an accumulator 79 for injecting the material M and an injection group or station 81 with a mold 9 housed in a bearing frame 8 IT.

Furthermore, in figure 14 an oleo-dynamic unit 83 is schematized to control the feed of the pressurized fluid P for controlling the injection nozzles, and a control room 85 which serves as control interface between the injection plant 100 and the user.

Lti a particularly advantageous embodiment of the present invention, the injection group or station 81 can include the injection equipment 31 of figure 9. Advantageously, the degasser 50 described in figures 10 to 13 can be provided between the extruder 77 and the accumulator 79. It is clearly possible also to arrange the degasser 50 in a different position upstream of the injection group 81 or to provide a different type of degasser according to particular requirements.

In a particularly advantageous embodiment of the present invention, a compensation mechanical joint 72 is provided between the extruder 79 and the injection station 81 for offsetting the axial expansions, which can be large and can generate a great force, caused by the heating to which the extruder 79 is subjected during the working phases. This joint 72 preferably includes a male duct slidable in a female duct, not shown in the figure for the sake of simplicity, inside which the material M flows, and furthermore suitable to maintain the seal by offsetting any slight angular misalignments. A blocking mechanism blocks and makes mutually integral the male/female ducts when the expansions have been stabilized, so as to avoid that during the injection the one slides inside the other. After the injection phase, during the cooling of the material M ₅ the two ducts are released. In the preferred embodiment of the present invention, it is provided for the injection plant 100 to be of the type with circular track, see figure 15, wherein the two above mentioned injection lines 70 have the respective injection stations 81 associated opposite to each other on a circular track 183 on which a plurality of molds 9 slide.

The track 183 furthermore comprises two extraction stations 185 for opening the mold, extracting the finished product and transferring it in the collection silos 73 through a respective collection path with rollers 190. Between each injection station and each extraction station 185 an intermediate station 186 is provided for cooling the mold, hi this way, each mold can be moved away from the injection group 81 once it has been filled, also thanks to the fact that the injection holes of the mold have been closed with the pellets 5. This makes it possible to insert immediately a new mold in the injection station 81, without the need for waiting the cooling of the molded material M. Therefore the production capacity of the plant increases significantly.

In the extraction station 185 each mold 9 is closed or opened by a press, not shown in the figures for the sake of simplicity.

Another press in the injection station 81 translates each mold 9, positioning it against the injection equipment 31, or more precisely to position each hole 7 against the respective nozzle 1.

In a particularly advantageous embodiment of the present invention, a mechanical blocking is provided to close the mold halves of each mold 9 so as to avoid outflows of the material M due to the effect of the backpressure inside the mold when it cools in subsequent stations. This mechanical blocking can be formed for example by a series of keys which enter into corresponding through holes provided on the edge of each mold half.

It should be noted that, by providing a same injection equipment 31, all the molds 9 of each station must have holes 7 in the same positions, i.e. at the respective nozzles 1, even if the finished products have different shape and weight. It is clearly apparent that the plant 100 is described merely by way of example, as it can be of any other type, for example it can present a different number of injection lines 70, additional stations to perform particular functions according to the works to be performed, a track of different shape or other else.

The substantial steps for the functioning of such a plant can be summarized as follows:

> to move vertically the mold 9, in order to position it against the injection equipment 81, each hole 7 of the mold 9 is closed by a respective pellet 5;

> to open the holes 7 of the mold 9 by coupling the pellets 5 by means of the coupling member 3 of the respective nozzle 1;

> to inject the material M in the mold 9;

^ to close again the holes 7 with the pellets 5 and to move away respectively the nozzles 1 and the mold 9 to detach the mold from the injection equipment 31 ; each pellet 5 closes the respective hole 7; > to transfer the mold 9 along the track 183 in a cooling station 186 and contemporaneously to translate a new hollow mold 9A, so as to bring it below the injection equipment 31; during this phase the accumulator 79 is loaded again with new material M for the subsequent injection; ^ to transfer the mold 9 along the track 183 in a discharge station 185, where it is opened to discharge the finished product on a collection line 190.

A self-cleaning continuous filter (not shown in the figures for the sake of simplicity) can be provided before the accumulator 79, in order to limit the dimension of the inert phases avoiding the block of the plant due to the obstruction of the ducts according to the characteristics of the available blend of the material M and therefore of the quality required for the finished product.

Furthermore, the degasser 50, if arranged between the extruder 77 and the accumulator 59, allows to maintain the processing area of the material M upstream of the extruder 77 separated from the injection area downstream of the accumulator 79 in each working phase, and therefore the changes in pressure in the injection equipment 81 will not affect the conversion and degassing process of the material M.

The phases of cooling, injecting the material and extracting the finished product are performed nearly at the same time for the molds arranged in the respective working station and they can be performed in less than 1 minute. The stations in figure 15 can be in different number and of different type than those described according to particular working requirements, for example they can be from 4 to 12 or more; furthermore, each mold 9 can have different shape and weight than the others, provided that its injection holes 7 correspond to the nozzles 1.

Further treatment phases can be also provided on the material M before the injection. For example the material M can be treated so as to be more suitable to the injection with treatments of milling, deferrizing, mixing with additives, drying, packing, pre-gelation or other.

The material M can be furthermore processed to make the phases or blends contained inside it, such as for example polymers or inert phases or other, more homogeneous and uniform, by means of the extruder 77. In the extruder 77 it is possible to provide a degassing plant, for example a high depression degassing plant with a water loop pump.

Specific additives can be furthermore provided, which improve the finished product, the transformation process or the environmental impact, such as for example compatibilizers, impact modifiers, stabilizers.

It should be noted that the injection plant 100 can be particularly advantageously applied in combination with the nozzles and the degasser described above; it is however possible to use it with nozzles and degassing systems at least partially different. Furthermore, the degasser can be used in plants of different type, and also the nozzles can be used with or without degasser and in plants with a different conformation than that described herein.

Finally, most of the plastics present in the solid waste and destined to the landfills or to the waste-to-energy plants can be reused and recycled with a plant of the type described above, by producing a finished product with mechanical and thermal performances very similar to those obtained with virgin plastics, even after normal ageing, with great advantages for the environment and for the production profitability.

The fields of application are in general that for the molded products and in particular merely by way of non limiting example the following are indicated: production of pallets of any type and dimension, of pots for the garden sector, of coils for electric cables; of platforms for modular interiors, of tiles for pavements, of modular elements for containing road rainwash, of containers, also underground, for waste, of containers for transporting fruit and vegetables or pieces of small dimensions in the engineering sector, of structures for sound-absorption panels, of elements for manholes and for sewerage systems, formwork systems for reinforcing concrete casting and for producing pavements, seats for sport centers, embankments and roadbeds, covering and other else.

Definitively, with the devices (the nozzle and the degasser) and with the - - molding plant (with the injection equipment and the hot chamber) according to the present invention, the costs significantly decrease for recycling, in particular urban or industrial waste, at the same time improving the quality and the mechanical properties of the finished product, so that to allow the use, also for consumer products, usually produced with virgin materials (such as plastic, wood, aluminum, bricks, sand) and also in specific cases for indirect contact with foods. Any lower mechanical performance can be balanced by the better structuration of the finished product.

It is clearly apparent that the nozzle, the degasser and the molding plant according to the present invention can be used in combination as described with reference to the illustrated example of embodiment, in order to obtain a plurality of advantages. However, it is also possible to use a plant without degassing device and/or nozzles of other type, or to use the nozzles of the type described in other plants with or without degassing device. It is also possible to use the degassing device in other plants with or without nozzles of the type described herein. Definitively, the advantages achievable with the degasser, with the nozzle or with the plant described herein can be validly applied also singularly.

It is understood that what is illustrated purely represents possible non-limiting embodiments of the invention, which may vary in forms and arrangements without departing from the scope of the concept on which the invention is based. Any reference numbers in the appended claims are provided for the sole purpose of facilitating the reading thereof in the light of the description hereinbefore and the accompanying drawings and do not in any way limit the scope of protection of the present invention.