The present invention relates to a method of emptying and collecting from a transport vessel, preferably of container size, unitary batches ^* of a granular or dust-forming product with creating dust in the sur¬ roundings.

Products of the aforementioned kind are, by their nature, dust- creating, dangerous to the environment, and difficult to handle pneumatically. Such products, the transport for which constitutes a problem which has not hitherto been satisfactorily solved, are extremely fine-grained, as are also hygroscopic, bridging inorganic and/or organic products, whereat as examples of products which are particularly difficult to handle can be mentioned anhydride (a gyp¬ sum quality), moist chalk, carbon black, maize starch, potato starch, different types of PVC raw-materials, such as suspensions, emulsions and pastes.

Difficultly handled products of the kind aforementioned when transported over long distances, e.g. by sea, are, at present time, carried in so-called pressure-vessel containers. An alternative made of trans- port for moving the said products over long distances is the so- called bulk trucks. When moving said products in large quantities, container ships and bulk carriers are often used, these being able to accomodate large unitary batches of said dust-forming or granular goods. When transporting these goods in container ships, standard transport vessels or pressure vessels of container size are nor¬ mally used, said vessels being of various designs with regard to the infeed and outfeed arrangements applied.

A standard transport vessel of container size and of present day design does not meet those requirements placed on the handling of

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the said granular or dust-forming products. Moreover, because the standard vessel is wrongly designed for the purpose in question, it is, in itself, difficult to handle, using standardized loading and emptying equipment, which is incapable of operating in a manner satisfactory for the purpose in question.

With regard to bulk cargo vessels, the large loads in question re¬ quire harbours to be provided with specially contracted silos, and cannot be used for products of the aforementioned kind for reasons of contamination, and especially for products which are hazardous to the environment, which products are not allowed to be handled in this way for environmental reasons. In addition, when transport¬ ing such goods in bulk carriers, there is a risk of said products being contaminated by previous loads, which in the case, for ex- ample, of plastics products in totally damaging. For the retailer and the purchaser the storage of these large loads also has the drawback of keeping large sums of money tied up in the store.

Many further disadvantages could be disclosed in this context, but those aforementioned are, at present, considered characteristic of present day techniques and methods.

The invention also relates to an apparatus for carrying out the -method of emptying and collecting from a transport vessel of con- tainer size batches of a granular or dust-forming product without creating dusty surroundings.

The characterizing features of the invention are set forth in the following claims.

The primary object of the invention is to eliminate the aforementioned disadvantages associated with the transport of dust creating, envi¬ ronmentally deleterious products of the kind mentioned, and to render the use of transport vessels of container size for said purpose both attractive and possible in practice, this object being achieved by providing a method which facilitates the emptying of transport

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vessels while preventing the surroundings becoming dusty in the pro¬ cedure thereof.

A number of exemplary embodiments of the invention will now be de- scribed in detail with reference to the accompanying schematic draw¬ ings, further features of the invention being made apparent in con¬ junction therewith.

Figure 1 is a partially broken sideview of a towing vehicle and a trailer on which a transport vessel of container size rests; also shown is an emptying unit for emptying a powderous or dust-forming product from the vessel without soiling the surroundings; Figure 2 illustrates the same arrangement as Figure 1 with the transport vessel and the emptying means coupled together in readiness for an emptying operation, and tipped at a suitable angle relative to the horizontal plane for emptying said vessel of its contents; Figure 3 is an end view of the lower part of the end wall of the transport vessel having an emptying opening at the bottom thereof, said open¬ ing being closable by means of a flap, which is shown in an uplifted position; Figure 4 is a view similar to Figure 3 with the emptying opening closed by an emptying bin which converges towards the middle and which has two feed screws of mutually different thread direc¬ tions for feeding goods located in the bin in the transverse direc¬ tion thereof to a central outfeed opening; and Figure 5 is a par- tially broken side view in larger scale of the emptying unit shown in Figures 1 and 2.

In the drawings the reference 10 identifies a towing vehicle of known kind on which a tippable trailer 12 is pivotably mounted by means of a swing device 11. Resting on a tipping frame 14 is a transport ves¬ sel 15 of container size. The frame 14 is pivotable about a rear bearing shaft 13 and the inner surfaces of the transport vessel are covered, in a known manner, with wear-resistant coverings 16 which seal said surfaces, and which are suitable made of metal, such as stainless steel, aluminium plate or the like coated with a plastics

material, such as polytεtra fluoro ethylene (Teflonv-^). In the il¬ lustrated embodiment, one end wall, 17, of the vessel 15 is provided with an emptying opening 18 which, during transportation of goods in said vessel, is closed by a swingable flap 19, said flap being shown in an upraised position, to expose said opening. Mounted on the frame 14 is an emptying unit, generally shown at 20, which is displaceable in the directions of arrows A. In the figure, the unit 20 is shown drawn towards the bearing shaft 13, in preparation for movement to¬ wards end wall 17 and the opening 18 to a position where a goods- -receiving bin 21 having an infeed opening 22 covers the opening 18 in said wall 17. It can be mentioned here that the opening 18. is closed, suitably from the inside thereof, with a flexible film of plastics material or like suitable material, which prevents the goods from escaping from the transport vessel before the bin 21 has been brought into sealing and locking engagement with the end wall 17 around said opening 18.

In the illustrated embodiment, the unit 20 can be displaced or rolled on the frame 14 of the trailer 12 in the directions of arrows A by hydraulic devices driven from the hydraulic system of the vehicle 10. In addition to the bin 21, the emptying unit also comprises a dust- -tight and gas-tight drive means 25 for the emptied goods, and a dust-tight and gas-tight, communicating line 26 extending between the bin 21 and a feeder 27 of the rotary vane type, said feeder being arranged to prevent gas or dust leaking to the surroundings and to prevent uncontrolled flow of goods through the unit 20. In accordance with the invention, the bin 21, the line 26 and the feeder 27 may be substantially rigidly formed rogether so as to be movable as a single unit on the frame 14. It can be mentioned in this context that it is an advantage to use vessels of 20 ft lengths, which is the normal standard measurement in this case, in combination with trailers of 30 ft length, which are also available as standard and which have the space to enable the emptying unit to be mounted on the same frame as the transport vessel . ^'

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Also shown in the Figure is a silo or like storage container 28. The storage container 28 has means (not shown) for coupling it to the feeder 27 from which said silo receives goods fed from the transport vessel through a connecting hose or the like. Figure 1 also shows a telescopic, hydraulic lifting device 29 in its retracted or rest position.

Figure 2, which in essential details coincides with Figure 1, illus¬ trates the next step of the method according to the invention. The elements shown in Figure 2 which coincide with those shown in Figure 1 are identified by the same references.

Figure 2 shows the transport vessel 15 and the unit 20 joined and locked together in a manner such that the bin 21 sealingly and lock- ingly surrounds the opening 18 in the end wall 17. In the procedural step illustrated in Figure 2, frame 14 has been tipped about the shaft 13 to a suitable angle^by means of the telescopic lifting de¬ vice 29, wherewith both the transport vessel 15 and the unit 20 are inclined at said angle substantially to the horizontal plane.

When the opening 18 is covered on the inside thereof with a flexible film-like sheet, e.g. a plastics film, the operator of unit 20 will rupture or slit said film, e.g. along the sides of the opening, prior to tipping the transport vessel from the substantially hori- zontal position shown in Figure 1, access to the film being had through an inspection opening or the like, which is normally closed by a cover 30. When the transport vessel has been tipped to an angle sufficient for goods to slide through the opening 18 and into the bin 21, said bin is, at least initially, with goods from the con- tainer or vessel 15. Should the goods cease to slide, however, fur¬ ther sliding of the goods can be caused by increasing the angle at which the transport vessel is inclined, or by using an electric or pneumatic vibrator, without increasing said angle, said vibrator preventing arching of the goods in the vessel 15.

Even though the angle CC of inclination of the vessel is increased,

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the goods in the vessel may stop running in the bin 21, thereby halting the emptying operation. To prevent this, the goods in the bin 21 can be loosened or broken up, by means of a vibrator of the kind aforementioned for example. Alternatively there can be used to this end a pneumatically operated blowing device, e.g. an ejector, arranged to act solely on the goods in the bin 21. In a further preferred embodiment there can be used, as indicated at 25, oppo¬ sitely acting conveyor screws in the transverse direction of the feed, said screws being arranged to feed the goods from the bin 21 into the communication line, from where the goods are passed to the discharge feeder 27. This feeder may be of any suitable kind, such as a rotary vane feeder, or a mechanical screw feeder for ex¬ ample.

Shown to the right of figure 2 is the silo 28 shown in Figure 1.

When using a silo plant 28, which may reach to a considerable height above the surface of the ground, the goods can be discharged through a line or hose 32 which is impervious to dust and granular material. The goods are moved through the line 32 by means of compressed air which is passed to the outfeeder 27 from a blowing machine 23 mounted on the frame 24 of the vehicle 10 through a line 31, which is con¬ nected to the outfeeder 27 at 50.

As will be understood from Figures 1 and 2 and the description rela- tive thereto, an essential factor for carrying out the method accord¬ ing to the invention is that at least one end wall 17 of the trans¬ port vessel 15 is provided with an emptying opening through which dust-like products or granular products stored in the vessel can be emptied therefrom.

Figure 3 is an enlarged view of the lower part of the end wall 17 in which the beforementioned emptying opening 18 is formed. In Figure 3 a closing flap 19 is shown in its upwardly swung position. The flap 19 is hinged on three hinges 33 which are attached to the end wall 17 above the opening 18, said flap 19 being pivotable on said hinges around shafts not shown. Arranged around the opening 18

is a number of lock fittings.34 arranged to receive locking pins of any suitable kind, for the purpose of locking the flap 19 in its downwardly swung position, in which position said flap sealingly abuts the surrounding defining edges of the opening 18 in the end wall 17.

Figure 4 is a view similar to that in figure 3, but with the excep¬ tion that the emptying opening 18 is closed from the outside by a substantial funnel-shaped receiving bin 35 for emptied goods. As will be seen from Figure 4, the receiving bin 35 is locked in its position of use by means of the lock fittings 34 and the lock pins 36.

Figure 4 also illustrates the outfeed opening 37 of the bin 35, on the inside of which opening 37 two conveyor screws 38 and 39 having mutually opposite screw directions are arranged for rotation. These screw conveyors are arranged to be operated by drive means (not shown) and to feed the products received in the bin towards the center thereof prior to said goods being discharged from the bin through the outfeed opening 37. The illustrated screw conveyors are only shown as an example of suitable drive means or conveying means for the goods present in the bin, and discharge of said goods from the bin can be suitably effected by a motor arranged externally from a hydraulic pump of the bin 35 and driven hydraulically by means of power taken through the power output of the towing vehicle. Other conveying devices are also conceivable within the scope of the inven- tion. Further, it is possible to use a pneumatic device for blowing goods out of the bin through the opening 37, suitably a pneumatic device of the ejector type.

As will best be seen from Figure 3, the emptying opening is closed from the inside of the end wall 17 by means of a flexible film 40 of, for example, a plastics material, to prevent the product escaping from the vessel when the closure flap 19 is swung away from the emptying opening 18. Subsequent to mounting the bin 35 on the end wall 17, the film 40 is cut away or ruptured with a knife or some other sharp instrument, preferably along the defining edges of the

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opening, there being arranged in the bin for this purpose an access opening 41 which is normally closed by a flap 30, as shown in Figures 1 and 2.

As an alternative to the arrangement shown in Figure 3 incorporating the sealing film of flexible material, such as a plastics material, said film can, in accordance with the invention* comprise, in a manner known per se, a bag or sack made of said film material and intended for storing the product in the transport vessel. Such a bag is suit- ably so formed as to lie against all parts of the inner wall of the vessel and to support thereagainst. Such an arrangement will prevent the inner wall of the transport vessel from becoming dusty or dirty, thereby reducing cleaning work to a minimum, since the inner walls of the vessel, even though they should present surfaces which might retain dust and granular material, do not come into contact with the product stored in the sack.

The emptying unit 20 illustrated in figure 1 and 2 is shown in larger scale and in more detail in Figure 5. Thus, in Figure 5 there is shown the receiving bin of Figure 1 generally identified at 21, and also the drive means 25 at the outfeed end of the bin. Also shown is the communication line 26 and the outfeeder 27.

In the Figure 5 embodiment, the bin 21 is provided with a connecting flange 42 and a sealing strip 43. The communication line 26 mainly comprises a tubular member which is sealingly connected to the outlet of the bin via a coupling flange 44 and a sealing ring 45, and is mounted ^' onto the outfeeder 27 at its upper end by means of a coup¬ ling flange 46 and a sealing ring 47, said outfeeder in a preferred embodiment having the form of a rotary vane feeder. The rotary vane feeder, which is shown in a broken view, has a rotary shaft 48 ar¬ ranged to drive a plurality of lamella or vanes 49, which succes¬ sively feed incoming material in the direction of arrow B into an outlet part 50, to which a drive means in the form of a compressed air hose 41 (Figure 2) is connected at 51 as a drive means for feeding the product from the outlet part 50 of the outfeeder 27 in

a direction substantially parallel with the rotary shaft 48 of the outfeeder, and out to a silo or the like through the hose 32 shown in Figure 2.

The intermediate part or communication line 26 illustrated in sec¬ tion in Figure 5 is provided with an inspection hatch 52, which can be closed and opened as desired by means of a handle 53. For the purpose of adjusting or determining the speed at which the product flows through the communication line 26, there is arranged in said line a plate-like butterfly valve 54, which can be turned and set manually as desired.

The elements which are assembled in this way to form a unit together form the emptying unit 20 shown in Figures 1 and 2. It is assumed n these figures that the unit is reciprocatingly movable in the direc¬ tion of arrows A, i.e. towards and away from a location in which the receiving bin 21 is in sealing contact with the end wall of the transport vessel. This arrangement obviates the need of displacing the transport vessel into contact with the receiving bin 21, but that instead the far less bulky unit 20 can be moved hydraulically or mechanically in its longitudinal direction to achieve contact bet¬ ween the bin 21 and the transport vessel 15.

An example of how the unit 20 can be carried and driven in its longi- tudinal direction is illustrated at the bottom of Figure 5, there being provided a platform 55 comprising beams or the like and fixed to the a tipping frame 14 (Figures 1 and 2), on which platform the unit is arranged for movement on supports 56. The unit 20 is dis¬ placed by means of rollers or other devices which move in suitable guides, there being provided for driving the unit in its longitu¬ dinal direction a piston-cylinder device 58 which is driven hydrau¬ lically, suitably by means of a separate hand pump, or mechanically.

In certain cases, however, it may be desirable for the unit as a whole to be placed stationary on a loading quay or the like. In such

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a case it may be difficult to tip both the transport vessel and the emptying unit. This can often create serious problems. In such a case it may be suitable, in accordance with the invention, to ar¬ range for the receiving bin 21 to be pivotable separately in rela- tion to the remaining part of the emptying unit, thereby enabling the transport vessel to be jointed to the bin and to tip the trans¬ port vessel together with solely the bin 21. A simple method of making this possible is, as illustrated in dash lines 59 in Figure 5, to make the outfeed pipe 60 of the bin flexible, e.g. through a bellow arrangement or the like. In this way both alternatives can be used of holding the unit completely stationary or of permitting the unit to move on rollers as shown in Figure 5.

In a preferred embodiment, emptying of the products from the trans- port vessel is influenced by the following parameters, namely the frequency of any vibrators used, the angle o6 at which the tipping frame is inclined, the rotary speed of the feed screws in the drive means 25, the setting of the butterfly valve 54, the rotary speed of the rotary vane feeder 27 and the pressure of the driving air connected to the outfeeder.

One skilled in this particular art will be able to optimize the set¬ ting or magnitude of the parameters so that a given material can be handled manually, although the invention also provides the possi- bility of automatizing the optimal values for any given product, for example by means of coded information, e.g. in the form of data cards, representative of each product, thereby eliminating the risk of human errors.

The invention is not limited to the illustrated and described embodi¬ ment thereof, but can be modified within the scope of the following claims.