GB2303115A

GB2303115A - Loading Bulk Material

Info

Publication number: GB2303115A
Application number: GB9514201A
Authority: GB
Inventors: Paul David Pratt
Original assignee: Turner Grain & Feed Milling Li
Current assignee: Turner Grain & Feed Milling Li
Priority date: 1995-07-12
Filing date: 1995-07-12
Publication date: 1997-02-12
Also published as: GB9514201D0; PE34697A1

Abstract

In order to load bulk, particulate material into a shipping container 12, an elongate screw conveyer boom 22 which has a feed opening and a discharge opening is set up with its feed opening outside and its discharge opening inside the container. The particulate material is fed into the container by this conveyor. A compaction plate unit (26, Fig 2) is mounted on the boom or booms and is movable beneath the booms to compress and compact the bulk material discharged from the discharge opening of the conveyor, to maximise the volume of material which can be introduced into the container. Preferably the compaction plate is movable from the inoperative position (Fig 3) to the operable position (Fig 2) by a ram (36) and compacting is by a ram (32).

Description

LOADING BULK MATERIAL This invention relates to the loading of bulk or granular material into an enclosed space such as a shipping container.

British Patent Specification 2 222 397 discloses a method and apparatus for loading bulk material into shipping containers, and the disclosure of that specification is incorporated herein by reference.

We have however found that it is possible to increase the density of packing of bulk material into shipping containers, beyond that achievable by use of the method and apparatus of British Patent Specification 2 222 397.

According to the invention, there is provided loading apparatus for loading bulk material into a shipping container, the apparatus comprising an elongate screw conveyer boom with a feed opening and a discharge opening, a drive for driving the conveyer screw in rotation, and a bulk material compaction plate unit movable beneath the booms to compress and compact bulk material discharged from the discharge opening.

The compaction plate unit is preferably mounted on the boom and can be moved between a retracted position, where it lies underneath the boom, to a compacting position where it extends generally downwardly beneath the boom, by swinging the plate unit about a hinge. The compaction plate unit preferably comprises a compaction plate mounted on a frame, and a hydraulic arrangement can be used to force the plate downwards, away from the frame and therefore to effect a compacting action.

Hydraulic rams may also be provided to move the compaction plate between its raised and lowered positions.

The invention also provides a method of loading bulk material into a shipping container, wherein an elongate conveyer with a feed opening and a discharge opening is positioned so that it extends into the container with the feed opening outside the container and the discharge opening within the container, the conveyer then being operated to discharge material into the conveyer, with discharged material being compacted within the container by a compaction plate as further material is discharged into the container.

Preferably, the container has an open end, through which the conveyer enters, and a closed end. Loading preferably takes place in the following sequence: (a) initially discharging material into the end of the container with the opening, until the initially discharged material reaches a preset level (b) advancing the discharge openings a preset distance within the container towards the closed end (c) discharging a further quantity of material and at the same time compacting the initially discharged material (d) repeating steps (b) and (c) until the discharge openings reach the closed end of the container (e) withdrawing the discharge openings a preset distance from the closed end (f) discharging a further quantity of material into the space above the compacted material (g) repeating steps (e) and (f) until the discharge openings are at the end of the container with the opening (h) withdrawing the conveyor from the container (i) closing the container.

By following these steps, a high density of packing of bulk material into the container can be achieved, which results in a reduction in shipping costs per unit volume.

It is preferred for the withdrawal of the discharge openings and the discharge of material in steps (e), (f) and (g) to take place automatically. The compaction plate will normally be raised to its retracted position during these steps.

The invention finds particular application where the bulk material to be loaded is highly compressible. One example of such a material is fish meal. The invention also has benefits when less compressible materials such as granular malt are to be loaded.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of apparatus in accordance with the invention, showing several stages in the loading of a container; Figure 2 is a side view, on a larger scale, of a part of the apparatus of Figure 1; and Figure 3 is an end view in the direction of the arrow A from Figure 2.

In Figure 1, a loading apparatus 10 is shown on the left hand side and a container 12 is shown on the right, being loaded with bulk material. The loading apparatus is mounted on a wheeled trailer 14 so that it can be towed into position. The container 12, which is a standard shipping container, is shown loaded onto a flat-bed lorry 16.

Many parts of the loading apparatus 10 are described in detail in British Patent Specification 2 222 397, and the reader is directed to that document for constructional details not apparent from the following description.

The apparatus has a hopper 18 which will, in use, receive material from a store of bulk material such as a silo.

Beneath the hopper 18 are two conveyor booms 20, each of which contains a feed screw (not shown in detail).

Material will flow from the hopper 18 into each of the booms 20 and, when the screws are rotated by an associated drive motor, the material will be conveyed to the discharge openings 22 of the conveyor booms.

As can be seen for Figure 1, the booms 20 can be advanced beneath the hopper 18 between a position where the discharge openings 22 are at the left hand end of the container and a position where the openings are at the right hand end of the container. The right hand end of the container is closed. The left hand end of the container is generally closed, but has an opening 24 through which the booms 20 can enter.

The loading apparatus shown can operate in the manner already described in British Patent Specification 2 222 397, but has an additional feature.

A compaction plate unit 26 is mounted beneath the booms 20, and can be moved between a retracted position 28 (Figure 2) and a compaction position 30.

The unit 26 comprises a frame 32 hinged to the booms 20 (or to framework adjacent the booms) at 34. A hydraulic ram 36 is attached to the frame 32 at 42 and can be extended and retracted to move the compaction unit between the positions 28 and 30. The unit also includes a compaction plate 38 and a pair of hydraulic rams 40 which can raise and lower the plate. The plate has a flat bottom surface and an apron 44 set at an angle to the bottom surface. The plate also has a lip 46, to add stiffness to the plate.

In use the booms, with the compaction unit 26 raised, are introduced into the container through the opening 24. The conveyors are operated to discharge flowable bulk material which drops into the container to form an uncompacted pile as at 48. Discharge is halted when the pile 48 reaches up to the lower edge of the opening 48 as a result of contact between a sensing wheel 50 and the container roof.

The booms are then advanced into the container, and discharge of material is recommenced. Alternatively, material may continue to be discharged while the booms are advanced.

Whilst material is being discharged, for example as shown at 52, the compaction unit 26 is operated to compress the previously discharged material. The ram 36 is first extended to lower the unit 26, with the plate 38 at this stage lifted up against the frame 32. With the unit lowered to the position shown in Figure 3, the plate will lie in a horizontal plane above the pile of material.

Next the rams 40 are extended to press the plate 38 down onto the top of the material pile and this causes the material to be compacted as can be seen at 54.

These steps are repeated until the booms reach the closed end of the container. At this point, the conveyor continues discharging until the whole cross section of the container, up to the roof, is filled by the material, as sown at 56. This state will be detected by monitoring the current consumption from the screws, as described in British Patent Specification 2 222 397. The compaction unit 26 is then raised and withdrawal of the booms begins, with discharge of material continuing to fill the void space 58 above the, now compacted, material fed into the container during the advancing of the booms.

When the booms are fully retracted and loading of the container is complete, the load will be compacted in the lower part of the container using the compaction plate unit described here, and compacted in the top half using main conveyor screw pressure. When the container is transported, this stratification of the material may disappear as a result of the movement of the container.

The angled apron 44 on the leading edge of the plate 38 ensures that when the compaction unit is lowered from its raised position, the discharged material is prevented from flowing over the top of the plate. The apron also helps to distribute the material across the width of the container helping to create a level surface of material for the compaction plate to act against.

The stroke of the compaction rams 32 can be designed with a knowledge of the degree of possible compaction of any particular material which is to be loaded. The hydraulic system incorporates settable pressure regulating valves to prevent excess pressure on compacted material causing the main loading conveyor to be force upwards.

This apparatus thus allows flowable solid particulate material to be loaded into a shipping container with a high packing density, without any direct operator intervention.

Claims

1. Loading apparatus for loading bulk material into a shipping container, the apparatus comprising an elongate screw conveyer boom with a feed opening and a discharge opening, a drive for driving the conveyer screw in rotation, and a bulk material compaction plate unit movable beneath the boom to compress and compact bulk material discharged from the discharge opening.

2. Loading apparatus as claimed in Claim 1, wherein the compaction plate unit is mounted on the boom and can be moved between a retracted position, where it lies underneath the boom, to a compacting position where it extends generally downwardly beneath the boom, by swinging the plate unit about a hinge.

3. Loading apparatus as claimed in Claim 2, wherein hydraulic rams are provided to move the compaction plate between its raised and lowered positions.

4. Loading apparatus as claimed in any preceding claim, wherein the compaction plate unit comprises a compaction plate mounted on a frame and a hydraulic arrangement adapted to force the plate downwards, away from the frame to effect a compacting action.

5. A method of loading bulk material into a shipping container, wherein an elongate conveyer with a feed opening and a discharge opening is positioned so that it extends into the container with the feed opening outside the container and the discharge opening within the container, the conveyer then being operated to discharge material into the conveyer, with discharged material being compacted within the container by a compaction plate as further material is discharged into the container.

6. A method as claimed in Claim 5, wherein the container has an open end, through which the conveyer enters, and a closed end, and loading takes place in the following sequence: (a) initially discharging material into the open end of the container, until the initially discharged material reaches a preset level (b) advancing the discharge openings a preset distance within the container towards the closed end (c) discharging a further quantity of material and at the same time compacting the initially discharged material (d) repeating steps (b) and (c) until the discharge openings reach the closed end of the container (e) withdrawing the discharge openings a preset distance from the closed end (f) discharging a further quantity of material into the space above the compacted material (g) repeating steps (e) and (f) until the discharge openings are at the end of the container with the opening (h) withdrawing the conveyor from the container, and (i) closing the container.

7. A method as claimed in Claim 6, wherein the withdrawal of the discharge openings and the discharge of material in steps (e), (f) and (g) takes place automatically.

8. A method as claimed in Claim 6 or Claim 7, wherein the compaction plate is raised to its retracted position during steps (e), (f) and (g).