GB2268231A

GB2268231A - Liquid container and dispenser

Info

Publication number: GB2268231A
Application number: GB9312906A
Authority: GB
Inventors: Roger Andrews
Original assignee: TNT MATERIALS HANDLING Ltd
Current assignee: TNT MATERIALS HANDLING Ltd
Priority date: 1992-06-23
Filing date: 1993-06-22
Publication date: 1994-01-05
Also published as: GB9213300D0; GB9312906D0

Abstract

To discharge a viscous fluid 27 from a flexible bag B contained in a rigid box (not shown here) the upper part of the bag has two layers (22, 23) between which compressed air may be introduced through line 28. A feature of the construction is the coaxially nested connectors (25, 26) which enables the bag to be filled, with the connectors being then separable for discharge. <IMAGE>

Description

TITLE Containers This invention relates to containers and is primarily concerned with containers of the kind comprising a flexible plastics bag or bladder which is housed within a rigid box structure. Such containers are used for the bulk distribution of flowable materials which are discharged under gravity from an outlet in a lower part of the bag. The box is adapted for palletised handling and after use is returned to be filled with another bag. Generally, after use, the bags are discarded. Such containers may hold up to one tonne of material.

It has been found that where the bag contains a liquid of high viscosity, discharge of such a liquid slows down considerably as the bag empties due to the falling head. One method proposed for overcoming this disadvantage comprised the addition of a heavy metal plate or lid which simply pressed down on top of the bag.

In another proposed method to assist the discharge of the liquid a separate inflatable bladder was located between the top of the bag and the lid of the box with the bladder being inflated to press down on the bag to assist discharge of the liquid. Neither of these proposals has proved to be particularly satisfactory mainly because they involve additional apparatus to be used and time and labour is required to set up the container when discharge required. A further disadvantage has proved to be that the bag deforms considerably and tends to block up the outlet before complete discharge of the liquid has occurred.

It is one of the objects of this invention to provide a means of assisting the discharge of a viscous liquid from the bag without requiring input of additional apparatus and which will ensure that substantially the whole of the contents of the bag can be discharged.

Broadly, and in accordance with this invention, a container generally of the kind referred to includes a bag of which the upper portion at least comprises an inner layer and an outer layer provided with a coupling member through which a pressure fluid medium may be introduced between the..two said layers to assist discharge of the flowable material through the said outlet.

In an embodiment the bag is constructed from two sheet plastics materials which are joined generally circumferentially to form a bag for containing a fluid medium, the lowermost portion of the bag having a fluid outlet connector and the uppermost portion comprising at least two layers of material, the innermost layer or layers being adapted to contain a fluid medium with a bung for filling and the outermost layer incorporating a further bung co-operating with the inner bung and further provided with a means for coupling with a compressed gas.

With such a simple arrangement it has surprisingly been found that applying compressed air to the space between the laminate layers of the bag on the uppermost portion provides sufficient assistance to ensure uniform discharge of the product and furthermore by the use of a bag having an equatorial seam the upper portion collapses in a manner whereby substantially complete discharge of the product occurs without blockage or obstruction of the outlet.

Broadly, and in accordance with a second aspect of this invention, there is provided a method of discharging fluid materials from a flexible bag contained within an outer rigid container wherein pressure medium is applied between an outer layer portion of the bag and an inner layer portion of the bag which contains the fluid material to cause pressure to be applied to the fluid material and the inner layer to collapse as said material is discharged.

Further and preferred features of this invention are described with reference to the accompanying drawings, wherein: Figure 1 shows the liquid material containing bag in a near filled condition, Figure 2 shows the same bag in a condition when the material has been almost fully discharged, and Figure 3 shows a rigid outer box which contains the bag.

Referring firstly to Figure 3 of the drawings, a rigid palletised box container is shown comprising side members la, ib, ic and id (not visible) formed from tubular steel with a top member le and a base member if adapted for normal palletised handling. The components have an infill of rigid plastics material lg and include fastening members lh by which the sides and top may be detached, and the box transported in flat knock-down form to a user. The box also includes an outlet flap ij covering an outlet access aperture.

The box shown in Figure 3 is adapted to receive a bag or bladder B made of a flexible plastics material and of generally rectangular form when filled and as shown in Figures 1 and 2.

As shown in Figures 1 and 2, the bag B comprises a lower flexible plastics component 20 which is joined by seam welding at an equatorial flange 21 to an inner upper layer 22 and an outer upper layer 23. The lower layer 20 of the bag may include an outlet coupling flange 24 which co-operates with the outlet in the box which is closed by the flap lj in Figure 3. The inner upper layer 22 includes a filler coupling flange 25 which normally is connected coaxially with a further flange 26 provided on the upper layer 23. The composite bag assembly is normally transported in flat form and this is effected by folding through the use of a pleated construction as is known. In such a condition, the filling flange 25 is nested within the flange 26.

The filled bag which may contain up to one tonne of material is transported to the user in the box shown in Figure 3 and in order to effect discharge of especially viscous fluids 27, means are provided, in accordance with this invention, whereby a medium such as compressed air may be fed through an inlet line 28 into the space 29 between the inner and outer layers 22, 23. By maintaining a constant pressure, for example 1 psi within the space 29, the viscous medium may be discharged from the outlet 24 in a consistent manner and during this process the inner layer 22 collapses and ultimately becomes retroverted into the form as shown in Figure 2.

It has been found most surprisingly that by this relatively simple expedient almost complete discharge of even a very viscous medium through the outlet 24 may be obtained without the bag trapping pockets of material or obstructing the outlet 24 before full discharge has occurred.

In order to provide access to couple the air line 28, the top le of the box may be provided with a central flap similar to the flap 1j which may be opened to connect the line 28 with the coupling 26 and to release the inner filling aperture 25 if necessary.

In one practical construction, the parts of the bag 20, 22 are constructed from three plies of a plastics material with the outer layer 23 being constructed from one ply of a thicker material. In a typical construction the plies will be 80 p with layer 23 of 250 u of polyethylene. In one particularly simple embodiment of this invention the construction of a standard multi-ply bag is modified by the addition of a further outer layer 23 which is seam welded along with the other plies at 21 to form the complete structure.

The addition of the coaxial coupling members 25 and 26 involves very little modification to a standard assembly.

A further advantage of the invention is that the modified bag may be used with or without compressed air discharge assistance and may be contained within a standard box or a box which has been modified by inclusion of a suitable flap or aperture on the top.

It has been found that 1 psi is an adequate pressure to ensure discharge of even highly viscous materials whilst ensuring that pressure is easily contained by the outer box. In a modification, a pressure blow-off valve is provided and conveniently this is set at 2 psi. The aperture in the top of the box may be provided with suitable locking means whereby the flange 26 may be engaged therewith to prevent collapse and to retain the flange in position for coupling with the air line 28.

Broadly therefore, this invention provides the surprisingly simple discovery that by introducing air pressure between the laminate or ply layers of a bag, adequate discharge may be obtained and in addition provides a simple modification to an existing bag enabling the invention to be carried out.

Claims

1. A rigid container housing a deformable bag for containing a flowable material to be discharged from an outlet in the lower part of the bag, characterised in that the upper portion of the bag comprises an inner layer and an outer layer provided with a coupling member through which a pressure fluid medium may be introduced between the two said layers to assist discharge of the flowable material through the said outlet.

2. A container according to Claim 1, wherein the bag is constructed from two sheet plastics materials which are joined generally circumferentially to form a bag for containing a fluid medium, the lowermost portion of the bag having a fluid outlet connector and the uppermost portion comprising at least two layers of material, the innermost layer or layers being adapted to contain a fluid medium with a bung for filling and the outermost layer incorporating a further bung co-operating with the inner bung and further provided with a means for coupling with a compressed gas.

3. A method of discharging fluid materials from a flexible bag contained within an outer rigid container wherein pressure medium is applied between an outer layer portion of the bag and an inner layer portion of the bag which contains the fluid material to cause pressure to be applied to the fluid material and the inner layer to collapse as said material is discharged.

4. A rigid container housing a deformable bag containing a fluid medium substantially as described herein and exemplified with particular reference to the drawings.

5. A method of discharging a flowable material from a deformable bag containing same and substantially as herein described.