GB2382339A

GB2382339A - A liner system for bulk cargo containers

Info

Publication number: GB2382339A
Application number: GB0126315A
Authority: GB
Inventors: Michael Peter Douglas Massie
Original assignee: U B C Ltd
Current assignee: U B C Ltd
Priority date: 2001-11-02
Filing date: 2001-11-02
Publication date: 2003-05-28
Anticipated expiration: 2021-11-02
Also published as: GB0126315D0; GB2382339B

Abstract

A liner system for bulk cargo containers comprises a liner (1) which is shaped to fit the interior of a bulk cargo container and having at least one inlet (7) and at least one discharge chute (8) in the walls thereof. The liner is comprised of a double layer of air and watertight material (1,3), and quantities of water absorbent material (4) such as silica gel are provided throughout the space defined between the two layers (1,3). The material (4) may be replaceable in pockets and may be treated to change colour when saturated.

Description

DESCRIPTION "A LINER SYSTEM FOR BULK CARGO CONTAINERS" The present invention relates to a liner system for bulk cargo containers and, more specifically, to a liner system for bulk cargo containers which is resistant to the passage of moisture through the walls thereof.

It is known to provide liner systems for bulk cargo containers to prevent bulk cargos carried therein from coming into contact with the walls of the container and thereby being contaminated. Known liner systems generally comprises a bag which is shaped to fit the interior walls of the container. One or more inlets and a discharge chute are provided in the walls of the bag and in use these are aligned, respectively, with inlet ports and a discharge opening in the sides of container itself. Generally, the liner system is installed by placing it in the container and securing the bottom to the floor of the container by, for example, securing double-sided sticky tape between the liner and the container floor, or trapping the liner against the floor of the container using wooden batons which are nailed to the floor of the container. Then the liner is partially inflated to ensure that it fits into all the comers of the container. At this point the inlets and discharge chute in the walls of the liner are pulled through the corresponding apertures in the container to insure proper alignment of the liner in the container.

Once the lining system is properly positioned and secured inside the container, a bulk cargo can be loaded thereinto. Typically, this is done by inserting a filling tube through the or each of the inlets to feed the cargo, under pneumatic pressure, into the

interior of the container. Once the container is fully loaded the inlets in the liner and the inlet ports in the container are closed. When the container is required to be unloaded the discharge opening in the container is opened, the discharge chute in the liner is pulled through and the discharge chute is then opened to release the bulk cargo.

Many bulk cargos are shipped over large distances and the prevailing environment may change significantly during their journey. Thus, they experience wide changes in temperature and humidity. Generally speaking, container liners are made from air and water resistant materials, typically polythene. This is resistant to the passage of water from one side to another, but is still permeable to water vapour. In many instances bulk cargo containers are not filled fully and a space is formed between the top of the cargo and the ceiling of the container through which air circulates. Depending on the prevailing temperature and humidity, water vapour within this air space can permeate the polythene liner, thereby causing spoilage.

The rate at which water vapour permeates a polythene liner is directly related to the thickness or gauge of the polythene. In this regard, it will be understood that the thicker the polythene the more resistant it is to the passage of water vapour through it. However, liners made from heavy gauge polythene are heavy which makes them difficult to install and relatively expensive. Moreover, even heavy gauge polythene will allow the passage of some water vapour over a period of time.

As an alternative to polythene it is known to make liners from aluminium foil.

This material is highly effective in preventing water vapour passing from the outside of the liner to the inside, but it suffers from a number of serious disadvantages. Firstly, it

is extremely expensive to manufacture liners from aluminium foil when one compares this with the standard liners comprised of polythene. Secondly, aluminium foil liners require the exercise of considerable care during installation as they are prone to tearing.

It is an object of the present invention to provide a liner system for bulk cargo containers which is resistant to the passage of water vapour through the walls thereof.

It is yet another object of the present invention to provide a liner system for bulk cargo containers which is relatively inexpensive and which is robust enough to be installed easily.

According to the present invention there is provided a liner system for bulk cargo containers comprising a liner which is shaped to fit the interior of a bulk cargo container and having at least one inlet and at least one discharge chute in the walls thereof, wherein the liner is comprised of a double layer of air and watertight material, and quantities of water absorbent material are provided throughout space defined between the two layers.

Preferably, the water absorbent material is silica gel. Conveniently, this is located in pockets provided throughout the space defined between the two layers and the pockets are accessible to permit the silica gel to be replaced once it has become saturated.

Preferably, the silica gel is treated so that it changes colour once it is saturated thereby signalling that it needs to be replaced.

Preferably, the inner layer forms an enclosed bag which is adapted to be filled with material and the outer layer only covers that part of the inner layer which in use will be exposed to air pockets when in use within a bulk cargo container. Typically, the outer layer will extend over the top of the inner layer and down at least part of the sides thereof.

In this regard, it is anticipated that there will be little, if any, moisture laden air passing between the floor and side walls of the liner and the container where these are held in close contact by the weight of the cargo, but that there will be a pocket of air in the space formed between the top of the cargo and ceiling of the container.

Conveniently, hooks or loops are welded into the walls of the liner to facilitate hanging the liner within a bulk cargo container, and double sided sticky tape is provided along the floor of the container to facilitate securing same to the floor of the bulk cargo container.

Conveniently, the or each inlet in the liner is comprised of a sleeve welded or otherwise secured in an aperture in the liner. Preferably, each sleeve comprises closure means and additionally, water absorbent material may be incorporated in the material of the sleeve.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure I shows a perspective view of a liner system for a bulk cargo container in accordance with the present invention; and, Figure 2 shows an end view of the liner system shown in Figure 1.

Referring to the drawings there is shown a liner system comprising a seamless tube or bag I of air and water tight material, such as polythene. The bag I is shaped to fit the interior of a bulk cargo container and in this regard it is essential cuboid.

The upper half of the cuboid bag I is covered with an outer layer 3 of air and watertight material, again comprised of material such as polythene, to form an enclosed

space. Located at intervals throughout this enclosed space are bags of water absorbent silica gel 4. The actual quantity of silica gel incorporated into the enclosed space can be calculated to precisely match the estimated quantity of water vapour which will permeate through the outer layer. In this regard, it is known that silica gel can absorb up to one third of its own weight in water.

Welded into the top and side panels of the liner system are reinforced loops 5 which can be looped over hooks on the inner walls and ceiling of a bulk cargo container to support same therein. To further facilitate securing the lining system within a bulk cargo container strips 6 of double-sided tape are provided on the bottom panel of the liner system.

Four closeable inlet sleeves 7 are welded into the top panel of the liner system through which the liner can be filled. These inlet sleeves may be closed in any appropriate way, although it is envisaged that to prevent moisture passing through the opening defined by each, welding them shut would be the preferred option. To further reduced the likelihood of moisture passing through the inlet sleeves when closed, a sheet of material (not shown) may also be welded or otherwise secured, over the aperture in the outer layer 3 to form a double layer enclosing a space, into which, optionally, a quantity of silica gel has been introduced.

As with conventional liner systems a closeable discharge chute 8 is welded into the front face thereof.

Once installed within a bulk cargo container the liner system in accordance with the present invention is filled with bulk cargo through each of the inlet sleeves 7. As the

cavity defined by the bag I is filled with material the bottom and side panels thereof are pushed into close contact with the inner walls of the container, effectively preventing any movement of air therebetween. However, because the material does not typically fill the bag to the very ceiling of the container, as illustrated by the line 8 in Figure 2 representing a typical profile of carried material, the top and side panels above this level are held only loosely against the container. Thus moisture laden air is free to circulate.

The double layer formed by the bag 1 and the outer layer 3, together with the silica gel, form an active barrier to the passage of moisture into the bag 1. In this regard, any moisture which is able to permeate through the outer layer 3 is absorbed by the silica gel 4 before it can permeate through the walls of the bag 1. The outer layer 3 effectively limits the quantity of water reaching the outer surface of the inner bag I and the inner bag I resists the passage of moisture vapour therethrough for long enough for it to be absorbed into the silica gel.

It will be understood that the outer layer 3 could effectively enclose the inner bag I in its entirety. However, it is envisaged that it is enough for it to enclose only that part of the inner bag which lies above the level of the material contained therein.

Claims

CLAIMS 1. A liner system for bulk cargo containers comprising a liner which is shaped to fit the interior of a bulk cargo container and having at least one inlet and at least one discharge chute in the walls thereof, wherein the liner is comprised of a double layer of air and watertight material, and quantities of water absorbent material are provided throughout the space defined between the two layers.
2. A liner system according to claim I, wherein the water absorbent material is silica gel.
3. A liner system according to claim 2, wherein the silica gel is located in pockets provided throughout the space defined between the two layers and the pockets are accessible to permit the silica gel to be replaced once it has become saturated.
4. A liner system according to claims 3, wherein the silica gel is treated so that it changes colour once it is saturated thereby signalling that it needs to be replaced.
5. A liner system according to any preceding claim, wherein the inner layer of the liner forms an enclosed bag which is adapted to be filled with material and the outer layer only covers that part of the inner layer which in use will be exposed to air pockets when in use within a bulk cargo container.
6. A liner system according to claim 5, wherein the outer layer extends over the top of the inner layer and down at least part of the sides thereof.

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7. A liner system according to any preceding claim, wherein hooks or loops are welded into the walls of the liner to facilitate hanging the liner within a bulk cargo container, and double sided sticky tape is provided along the floor of the container to facilitate securing same to the floor of the bulk cargo container.
8. A liner system according to any preceding claim, wherein the or each inlet in the liner is comprised of a sleeve welded or otherwise secured in an aperture in the liner.
9. A liner system according to claim 8, wherein each sleeve comprises closure means.
10. A liner system according to claim 8 or 9, wherein water absorbent material is incorporated in the material of the sleeve.
11. A liner system for bulk cargo containers substantially as hereinbefore described with reference to the accompanying drawings.

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