GB2116938A

GB2116938A - Method and apparatus for handling bulk material

Info

Publication number: GB2116938A
Application number: GB08306753A
Authority: GB
Inventors: Dale Patrick Elwell
Original assignee: Cyclonaire Corp
Current assignee: Cyclonaire Corp
Priority date: 1982-03-16
Filing date: 1983-03-11
Publication date: 1983-10-05
Also published as: AU1241883A; JPS58167322A; AU558894B2; GB8306753D0

Abstract

To transport dry bulk solids in a container 1, the container floor is covered with air permeable material 3 and then filled with the dry bulk solids 17. An opening is formed in the container at or close to the floor. A discharge shute 23 from an air supply is attached to said opening and the other end of the container is elevated so that the air stream arriving in the container through the permeable material facilitates flow of said solids from the container. <IMAGE>

Description

SPECIFICATION Method and apparatus for handling bulk material The present invention relates to the conveying of free fiowing dry bulk materials such as flour, sugar, various plastics, minerals and the like. It is not limited to any specific material. In particular, it provides an improved method and apparatus for the removal of these materials from a container in which they have been placed for transportation, storage, or other purposes.

Bulk materials of this nature have traditionally been transported in pressurised road or rail tankers or pods. These specialised units are not always readily available and are necessarily expensive. The present invention has been developed to enable standard ISO containers to be used more effectively in the transport and storage of dry bulk materials.

Although these ISO containers, are nominally8ft x 8ft x 20ft, and the invention will be described hereinafter with reference to this particular application, it is not limited to this type of container or this particular size.

Many bulk products are already carried by these containers. Examples such as grains and minerals are usually easily removed from the container by gravity and there is normally no problem with contamination, nor does it matter if some product residue remains in the container.

With products such as foodstuffs or plastics, however, contamination is a critical factor. The product must not be allowed to come into contact with the walls of the container or any foreign material. Any wastage or spillage of foodstuffs could present health problems, while with plastics, wastage or spillage can be extremely expensive. Until now there has been no successful method of handling these products in standard containers, although many systems have been tried. It is known to line the container with a disposable or reusable plastic sheet. The product is then introduced either by gravity or pneumatically and the container is transported in the usual manner. However, difficulties arise when efforts are made to remove the product and most systems to not overcome bridging, ratholing and hang-ups of product in the container.Some systems damage the product during transfer, while others contaminate, spill or otherwise waste the product.

It is an object of the present invention to overcome or at least ameliorate many of these problems in order to allow the successful transportation of dry bulk solids in standard containers.

According to one aspect of the invention, there is provided a method of transporting dry bulk solids by means of a box-like container including the steps of: substantially covering the floor of said container with at least one air permeable pad; filling said container with dry bulk solids; transporting said container; forming an opening in one end of said container at a point adjacent said floor; attaching a discharge shute to said opening; connecting said pad to an air supply; elevating the other end of said container; and passing an air stream through said pad to aerate said solids and facilitate the flow of said solids from said container.

In preferred embodiments, the container is first lined, preferably with a flexible plastics material. An aeration pad is then placed on the floor of the container, inside the liner. Alternatively, the pad may be incorporated integrally with the liner. The product to be conveyed is then placed on top of the pad, the liner closed and the container transported to its destination. When the material is to be removed from the container, a novel discharge shute is applied to the container adjacent its floor and the liner is opened to allow the product to run into the shute. The shute in turn is preferably connected to a pneumatic conveyor and the container is tilted from the horizontal towards the shute. Pressurised air is then introduced to the pad, which inflates and aerates the product.This not only supplies make-up air for the pneumatic conveyor, but, more importantly, it also reduces friction between the product and the container floor, thereby promoting the flow of the product to the shute. Preferably, the shute is also provided with an air permeable floor by an aeration pad located on the bottom wall of the shute.

The invention also provides a novel shute for use in performing the method described above. The shute includes an elongated mouth adapted to engage the lower portion of one end of said container at a point adjacent said container floor, a hatchway formed in the wall of said shute for providing access to open a liner provided in said container, thereby to permit dry bulk solid material within the container to run into said shute, an exit adapted for attachmentto a pneumatic conveyor, and at least one air supply pipe extending through the wall of the shute for attachment to at least one aeration pad located within the container.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a cut-away perspective view of a container prepared in accordance with the present invention.

Figure 2 is a cut-away perspective view of a container being unloaded in accordance with the present invention.

Figure 3 is an enlarged, part section of Figure 2 showing the product discharging from the container to the shute.

Figures 4to 7 illustrate successive steps in one particular manner of using the invention to load, transport and unload dry bulk material from a standard container.

Figure 8 is similar to Figure 7 but illustrates a container being unloaded from a tipping truck.

Referring to the drawings, a standard ISO container 1 is first fitted with a plastic liner 2 as shown Figures 1 and 4. The liner may be reusable or disposable. Disposable liners are normally of Polyviny-chloride sheeting, seam welded to form a bag open at the top for filling. Reusable liners are normally of coated woven polyethylene fabric also shaped as a bag open at the filling point.

One or more aeration pads 3 are then fitted to the container floor 4, inside the liner as shown in Figure 1. The pad is best illustrated in Figure 1 and is made of a sandwich of two fabrics 5 and 6 joined to form an envelope. The lower side 5, which covers the liner floor is impervious to air. However, the top side 6 is porous and is exposed to the product which sits on top of it.

Preferably, the pad is compartmentalised, the number of compartments depending on the size and shape of the container. Five compartments (7,8,9, 10 and 11) have been found to be the most effective for standard containers. Each compartment has a separate air inlet 12 and 13 and all air inlets are placed along the front end of the pad which is exposed by the open container doorway 14. Three parallel compartments 9, 10 and 11 run longitudinalliy and cover the width ofthecontainerforapproxi- matelytwo thirds of its length from the door end.

Each of these compartments has a separate air inlet 12. Two other parallel compartments 7 and 8, also placed longitudinally, cover the remaining one third of the container floor area. These latter compartments are each fed by an inlet tube 13.

The pad is able to be rolled up for storage or transportation when not in use. When installed flat on the container floor it is held in place by fixings attached to its perimeter (not shown).

Once the pad is in position, a bulkhead 15 is fitted across the open doorway 14 to retain the front face 16 of the liner 2 as shown in Figures 1 and 4. The bulkhead is preferably formed of wood. Installation of the liner 2 can now be continued to define a continuous bag, extending around the four walls, top and floor of the container.

As shown in Figure 5, the product 17 is now introduced to the liner through the container top 18 or through an opening 19 above the bulkhead 15.

The product may be introduced by gravity or by pneumatic or other mechanical conveying, depending on the container type and the plant design.

The installation of the liner is then completed so as to substantially seal the container and the container doors 20 are closed securely for transport or storage.

The inlet opening 18 at the top of the liner may be sealed with tape or ties as required.

To remove the product from the container, the container is first placed on a tilt frame 21 as shown in Figure 7 or left on a tipping truck tray 22, as shown in Figure 8. The doors 20 are opened and a discharge shute 23 is then applied to the opening 24 beneath the bulkhead 15, as illustrated in Figure 2. In some containers, an auxiliary rear door is provided along the bottom edge of the container and in such cases the shute may be applied directly to this opening without any need for a bulkhead.

As best shown in Figure 2, the discharge shute 23 includes top 25, bottom 26 and side walls 27. The shute resembles a funnel and its tapered walls extend from an elongate mouth 28 to an exit port 29.

The mouth 28 is adapted to sealingly engage the opening 24 beneath the bulkhead 15, while the exit preferably communicates with a pneumatic conveyor unit 30 (Figure 7). The mouth of the shute is sealed to the container and bulkhead by a peripheral flange and over-centre latches (not shown). The shute top wall 25 includes a hatchway 31 as shown in Figure 2. With the shute in position as illustrated in this figure, the hatch door 35 (see Figure 3) is opened to provide access through the hatchway 31 to the liner 2. The liner can then be slit or otherwise opened to allow the product to fall through into the shute, as shown in Figure 3. Opening the liner through the hatchway 31 ensures that no product is wasted at the initial opening stage since the shute is in position to catch any material falling from the open liner.

With disposable liners, the liner may simply be slit to remove the product. With reusable liners, however, one or more permanent outlets may be provided below bulkhead 15. These can be closed and reopened by ties accessible through the hatchway 31. Preferably, however, the reusable liner is provided with a special discharge port in the form of an opening extending substantially entirely across the opening below bulkhead 15 to provide maximum discharge area. The discharge port may be sealed by a flap releasably held in sealing engagement with the liner by ties or a VELCRO-type sealing strip.

As shown in Figure 2, the shute includes an air supply manifold 32 from which a plurality of air supply pipes 33 extend through the top wall of the shute. Once the shute is in position on the container, these pipes 33 are connected to the pad air inlets 12 and 13 by clamps 34, access being provided through the hatchway 31. The hatchway 31 is then closed off by the hatch door 35 (Figure 3) completely sealing the system. The manifold 32 carries a number of vaives (not shown) for directing air to selected pipes 33 as may be required. The manifold connects to any convenient source of compressed air.

The bottom wall 26 of the shute 23 is preferably covered with an aeration pad 36, supplied with air through pipe 37 (Figure 2), separately valved from the manifold 32. This pad 36 functions in the same way as the main pad 3 described above and provides the shute with an air permeable floor.

The container is now elevated, preferably to an angle in the order of 10 to 15 degrees, and air is supplied to the aeration pads 3 via the manifold 32.

When air is introduced to the pads they inflate under pressure and the air permeates through the top sides 6, forming a layer of air between the pad and the product, reducing friction between the two and enabling the product to flow readily to the shute and into the pneumatic conveyor unit 30 for subsequent transport. The additional pad 36 functions the same way within the shute itself.

The pneumatic conveyor unit 30 may be of any suitable type, but is preferably of the type known by the Registered Trade Mark CYCLONAIRE. This includes a transfer vessel which generates a vacuum on its inlet by use of a venturi. This vacuum assists the product to flow from the shute 23 into a suitable vessel where it is pressurised and thereby discharged through a conveyor line to its required destination.

It will be appreciated that the illustrated system is self contained and fully enclosed. The product need never be exposed to the atmosphere to any significant extent.

Although the invention has been described with reference to a specific example, it will be appreciated that the invention is not limited to this particular embodiment and that it may be embodied in many other forms.

Claims

1. A method of transporting dry bulk solids by means of a box-like container comprising the steps of: substantially covering the floor of said container with at least one air permeable pad; filling said container with dry bulk solids; transporting said container; forming an opening in one end of said container at a point adjacent said floor; attaching a discharge shute to said opening; connecting said pad to an air supply; elevating the other end of said container; and passing an air stream through said pad to aerate said solids and facilitate the flow of said solids from said container.

2. A method as defined in claim 1 wherein the interior of said container is first lined and subsequently substantially sealed with a liner of plastics sheet material.

3. A method as defined in claim 2 wherein said opening is formed by gaining access to said liner through a hatchway formed in the wall of said shute.

4. A method as defined in claim 1,2 or 3, wherein the discharge end of said shute communicates with a pneumatic conveyor for drawing air and solids from said shute.

5. A method as defined in claim 1,2,3 or 4, wherein said container is filled through an opening in the top of said container.

6. A method as defined in claim 1,2,3 or 4, wherein said container is filled through an opening in the front of said container.

7. A method as defined in any preceding claim, wherein a flow of air is passed through an air permeable floor formed in the bottom of said discharge shute.

8. A method as defined in any preceding claim, wherein air is supplied to said pad through at least one air supply pipe extending through the wall of said shute.

9. A method as defined in any preceding claim, wherein said pad is compartmentalised.

10. A method as defined in claim 9, wherein said pad has more compartments adjacent said one end of said container than at said other end.

11. A method as defined in claim 9 or 10, wherein air is separately supplied to each compartment.

12. A method as defined in any preceding claim, wherein a plurality of said air permeable pads are used.

13. A method as defined in any preceding claim, wherein a bulkhead is fixed across said one end of said container and positioned above the floor of said container to form a restricted opening from said container when said one end is opened.

14. Apparatus for use in performing the method of claim 1 including a shute having an elongate mouth adapted to engage the lower portion of one end of said container at a point adjacent said container floor, a hatchwayformed in the wall of said shute for providing access to open a liner provided in said container, thereby to permit dry bulk solid material within the containerto run into said shute, an exit adapted for attachment to a pneumatic conveyor, and at least one air supply pipe extending through the wall of the shute for attachment to at least one aeration pad located within the container.

15. Apparatus as defined in claim 14, wherein an air permeable floor is formed in the bottom wall of said shute.

16. Apparatus as defined in claim 14 or 15, wherein an air supply manifold is attached to the top wall of said shute, with air supply ducts extending through said top wall from said manifold for connection to said aeration pad.

17. Apparatus as defined in claim 16, wherein said manifold includes valves for individually controlling the air supply to said ducts.

18. Apparatus as defined in claim 14, 15, 16 or 17, wherein said hatchway is formed in the top wall of said shute.

19. Apparatus as defined in claim 15, wherein said shute floor is substantially co-planar with said container floor when said shute is operatively connected to said container.

20. Apparatus as defined in any one of claims 14 to 19, wherein the mouth of said discharge shute extends substantially for the entire width of said container floor.

21. Apparatus as defined in any one of claims 14 to 20, wherein said mouth is bounded by a peripheral flange adapted for sealing engagement with said container.

22. Apparatus as defined in any one of claims 14 to 21,further including: a plastics liner for covering the interior walls of said container, and at least one aeration pad for covering the floor of said container.

23. Apparatus as defined in claim 22, wherein said plastics liner is a continuous bag.

24. Apparatus as defined in claim 22, wherein said pad is formed as an envelope of two fabrics, the fabric on the lower side being impervious to air and the fabric on the upper side being porous to air.

25. Apparatus as defined in claim 22, 23 or 24, wherein said liner has a closeable top opening capable of accepting dry bulk solid material and a lower opening capable of being closed and reopened a number of times.

26. Apparatus as defined in claim 22, 23,24 or 25, wherein said pad is integral with said liner.

27. A method of transporting dry bulk solids substantially as herein described with reference to the accompanying drawings.

28. Apparatus for removing dry bulk solids from a box-like container substantially as herein described with reference to the accompanying drawings.

29. A method of handling dry bulk solids using a container wherein the floor of the container is covered with an air permeable pad, the solids are held in the container so as to cover the pad and the solids are subsequently removed from the container while an air stream is passed through the pad.