IES940087A2 - Container for flowable material and method of manufacture - Google Patents

Abstract

A method of manufacturing a panel of a container for transporting and/or storing a flowable material where the container comprises a plurality of side wall panels, where each panel is formed of a substantially flat sheet of rigid material and has a main side wall portion. The method comprises, for each panel forming an upper seam along an upper edge of the sheet, forming a first seam along a first edge of the sheet and forming a second seam along a second edge of the sheet, the second edge being opposite the first edge and the upper seam being transverse to each of the first and second seams.

Description

CONTAINED FO^ FLOWAbLE MATERIAL. AMD METHOD OF MANUFACTURE The present invention relates to containers for the storage and transportation of flowable material, and more particularly, to containers which can be readily accommodated in a shipping container or on a pallet for stacking one on top of the other, and a method of manufacture of the same.

A known type of liquid container designed to facilitate transportation comprises an outer shell which is of a generally rectangular prismatic shape, and an inner shell in which the liquid is received, the inner shell being secured to the outer shell and having a generally cylindrical shape. The cylindrical shape of the inner shell is particularly well adapted for the transportation of liquid, partly because of its strength and partly because there are no corners in which small residual amounts of liquid can lodge. The rectangular shape of the outer shell facilitates stacking of the corners on pallets or platforms and on top of similar containers, and at the same time, the outer shell physically protects the inner shell. However, this known type of liquid container is relatively expensive, and the cost factor is especially important where, as frequently happens, transportation costs rule out return of the empty container for re-filling, so that it has to be scrapped after a single use.

Although such containers are generally used for the transportation of liquids, they can also be used for the transportation of semi-liquids, and solids which are in the form of powdered or granular materials, so that they act as liquids in the sense that they are flowable, and also gasses, particularly gasses.hajxing~a~speciflcTjravity noN Γ UNDER ΐ RULE 23 ί SECTION 23 AU J f S JNL No L„ .Or L940 Οε7 - 2 greater than unity. The physical characteristic which distinguishes those products which the container is adapted to carry is the ability to flow.

It is the principal object of the invention to provide a method of manufacture of a low cost container for flowable material of the double shell type.

According to one aspect of the present invention, there is provided a method of manufacturing a panel of a container for transporting and/or storing a flowable material, the container comprising a plurality of side wall panels, each panel formed of a substantially flat sheet of rigid material and having a main side wall portion, the method comprising the steps of, for each panel: (i) forming an upper seam along an upper edge of the sheet; (ii) forming a first seam along a first edge of the sheet; (iii) forming a second seam along a second edge of the sheet, said second edge being opposite said first edge and said upper seam being transverse to each of said first and second seams.

Preferably, said panel includes a corner portion located adjacent the side wall portion, and further comprising the steps of: (iv) forming an elongate bend in the sheet along a line which lies between said first and second seams, and nearer said second seam than said *.»40 08 7 - 3 first seam, such that the main side wall portion is defined between said bend line and said first seam, and the corner portion is formed between said bend line and said second seam; (v) attaching a foot member to the corner portion, said foot member attached to said sheet material by at least one fixing device; and (vi) forming a second bend along a second elongate bend line between the first bend line and the second seam, to form an edge portion adjacent said corner portion, the second seam being carried on said edge portion.

The invention includes a method of assembling a container from a plurality of panels manufactured according to the above aspect, the method of assembly comprising: engaging a said first seam of a first said panel with a second seam of a second said panel and compressing together said seams to form a first compressed seam joint; engaging a first seam of the second panel with a second seam of a third said panel and compressing said seams together to form a second compressed seam joint; engaging a first seam of the third panel with a first seam of a fourth panel and compressing said seams together to form a third compressed seam joint; engaging a first seam of the fourth panel with the second seam of the first panel and compressing said seams together to form a fourth compressed seam joint, 400ΡΊ - 4 wherein said first to fourth panels are joined together to form a tubular shell structure.

Preferably, the method of assembly further comprising the step of: (vii) closing the tubular shell structure by fitting an end closure member comprising a sheet of material having a peripheral downwardly depending lip, inserting the downwardly depending lip into a socket of the upper seam, and bending a portion of the upper seam over the periphery of the lid to enclose the downwardly depending lip in the upper seam.

The invention includes a panel manufactured in accordance with the above aspect, or a container assembled in accordance with the above method.

A method of manufacturing a container in accordance with a specific method and embodiment of the invention, will now be described by way of examples only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of the container mounted on a pallet, Figure 2 is a sectional detail view of a lid and inlet construction of the container; Figure 3 is a detail section through a rolled seam joint in the course of assembly, Figure 4 is a view similar to figure 3, but showing a later stage in assembly of the rolled seam joint, ¢940087 - 5 Figure 5 is a cross-section through a rolled seam joint used for a detachable lid, Figure 6 is a perspective view of an outer shell of the container shown prior to final assembly; Figure 7 is a plan view of one of the panels comprising the outer shell of figure 6; Figure 8 is a schematic plan view of first and second seams of seam joint between two adjacent panels of the outer shell, prior to final formation of the seam joint; Figure 9 is a schematic plan view of the seam joint of figure 8 after completion of the joint; Figure 10 is a detail of an inlet of a lid of the container; Figure 11 is a diagrammatic side view of an inner shell, shown removed from the outer shell; Figure 12 is a detailed view showing the attachment of an outer pipe to the inner shell; Figure 13 is a perspective view from inside the outer shell looking towards an outer opening in the outer shell; and Figure 14 shows a modified outlet pipe.

According to a specific embodiment of this invention, a container for transporting and/or storing flowable material comprises an outer shell of rigid or semi-rigid construction which has a generally prismatic shape 4 94008 7 - 6 comprising four side panels, and an inner shell to receive the material to be contained, the outer shell being made as a tube open at the top and bottom ends and having a closure element secured to one of the open ends by a first rolled seam joint. The closure element may comprise a lid or a bottom which itself substantially closes that end of the tube accordingly. Preferably part of each wall of the tube projects beyond the rolled seam joint and is turned over on to the outside of the closure element to secure that element to the tube.

The tube comprises four panels, each having a side wall portion and a corner portion, such that the corner portion is angled with respect to the main plane of the side wall portion. Each panel is provided with first and second seams such that, when the panels are assembled to each other to form the tube, a first seam of a first panel engages a second seam of a second panel; and the engaged seams can be compressed to form a compressed seam joint 10.

In another construction, the closure element comprises a support attachable to the tube by the rolled seam joint, to which a lid can be releasably secured. In that case, the support may comprise a frame which fits into the open top end of the tube, and provided with a series of screw-threaded parts, the lid having a turned down rim which fits outside the walls of the tube when the lid is in position, and a series of screws passing through the holes in the lid and engaging respectively in screwthreaded parts of the support to releasably secure the lid to the support.

The construction of the embodiments may allow the outer shell to be made of thin sheet material, for -940087 - Ί example, mild steel of 20 S.W.G. Without any rolled seam joint, a tube of say 1 metre square cross-section and 1 metre in depth would not in itself have a sufficient rigidity to protect the inner shell. Even when the lid and bottom are added, the additional rigidity provided by the lid and bottom would not be adequate, especially if the lid is detachable.

By using rolled seam joints around the ends of the tube (ie. at the top and bottom) much greater rigidity is obtained in addition to securing the closure element (lid, bottom or lid support) to the tube. It has also been found however, that the rolled seam joint gives another advantage in that it permits a configuration of the outer shell which readily admits of stacking the containers one on top of another, whilst avoiding the formation of sharp edges which could damage other containers.

The term ’’rolled seam joint is used to describe a joint in which a marginal portion of the sheet material forming one element is bent to provide a socket in which a marginal portion of another sheet element can be received, and at least a double thickness of sheet material is provided alongside the socket, and in which the joint is secured by closing part of one element over the other element to hold the marginal portion of the other element in the socket.

The term compressed seam joint is used to describe a joint in which a marginal portion of a first sheet element is bent with respect to an adjacent portion of the first sheet element to provide a socket in which a marginal portion of a second sheet element can be received, and in which the joint is secured by closing the socket such that the marginal portion of the second sheet -940087 - 8 element is squeezed in the closed socket between the marginal portion and an adjacent portion of the first sheet element, so as to retain the marginal portion of the second sheet in the socket.

Preferably the container has a lid an inlet hole 11 formed in the lid and the top of the inner shell and the marginal portions of both the lid and the inner shell around these inlet openings may be nipped together, whereby the inner shell is attached to the outer shell.

The inner shell may be made of flexible material. In one embodiment, the flexibility of the inner shell construction is preferably such that it will at least partially collapse when empty, but it is capable of expansion to a maximum internal volume when filled with a flowable material, and therefore the term expansion is used to describe the opening of the inner shell to its maximum volume, and is not intended to include actual inflation. On the other hand, it is preferred that the inner shell is strong enough not to suffer substantial stretching due to stress applied by the internal load when it is full. By manufacturing the inner shell in flexible material, very considerable manufacturing cost savings can be effected, whereby the container can be used in situations where the cost of a double shell container of the known (rigid inner shell) type container presently used for carrying liquids would be prohibitive.

The inner shell may be made of plastics film of thin sheet material having the required degree of strength and flexibility. A suitable material is polyethylene and a particularly effective material is made of cross-laminated high and low density polyethylene films. Compound films, such as co-extruded films, having two or more layers of 0 08 7 - 9 materials with differing physical properties may also be employed.

The inner shell may have a rigid or semi-rigid planar sustaining element, secured to one of its sides to resist creasing of that side. It is desirable to prevent creasing to avoid trapping material in the creases. This applies particularly of course, to the bottom of the shell, when materials such as semi-liquids or powders would be prone to lodge in any available creases, even when the container is being emptied.

The planar sustaining element may comprise a sheet of card such as cardboard, boxboard, millboard strawboard and the like secured to the side of the inner shell by adhesive. The sustaining element could equally comprise a sheet of rigid plastics material, plywood or hardboard, but the use of card is preferred because it is relatively cheap.

The planar sustaining element can be attached to the shell over its entire surface, which is useful in resisting creases. However, it might be possible to secure the sustaining element to the inner shell only around the edges of the element, for example, by using adhesive tape. Providing that side of the shell is stretched when the element is attached to it, the arrangement should be adequate to prevent substantial creasing.

Alternatively, the inner shell may comprise a more rigid container, eg. a large plastics bottle.

It is further preferred that the outer shell is of generally rectangular prismatic shape. This retains the 0 08 7 facility for stacking which is a feature of the known double shell type container. The outer shell may have secondary formations to give it additional strength, eg. dishing or ribbing, and it has been found that the diagonal or chamfered corner portions are an effective way of increasing the rigidity of the outer shell.

In another embodiment, the panels of the outer shall comprise two substantially L-shaped members (as seen in plan) joined together, so that on the arm of each ’'L’' forms a side wall of the shell and the base of the L forms a corner portion.

In one construction, the marginal portions of the lid and the inner shell are nipped between a flange on an inlet adapter and a collar, so that the attachment of the inner shell to the outer shell is provided by the adapter and collar combination.

An outlet opening is preferably formed in one wall of the outer shell near to the bottom of the container, for an outlet pipe and/or tap, and it is preferred to provide a substantially imperforate rigid barrier on the inside of this opening to protect the inner shell against damage by anything inserted through the outlet opening. Alternatively, the outlet may be formed in the bottom wall of the inner shell to permit removal of the contents of the inner shell through the bottom of the container. In some instances, the outlet may be omitted altogether, in which case, the container is emptied by sucking the contents out through the inlet.

Referring to figures 1 to 13 of the accompanying drawings, the particular container which is described hereafter, is intended for the transport of liquids, and 494008/ - 11 more particularly, for the transport of liquids on platforms or in containers such as the I.S.O. containers used for international transportation purposes. Although a container in accordance with the specific embodiments of the invention could be used for the storage and/or transport of virtually any kind of liquid, it is thought that the most likely use is for transportation of nondangerous liquids, since dangerous liquids may require containers of somewhat more substantial construction. On the other hand, a container in accordance with the specific embodiment of the present invention can be used to transport liquids of relatively high specific gravity, for example up to 1.4. Indeed, the container can also be used for transporting semi-liquids, granular materials and powdered materials which will have even higher specific gravities.

The container is a double-shell construction, and to that extent it resembles a known type of container used for the transportation of non-dangerous liquids, which has rigid inner and outer shells. Referring to figure 1 of the accompanying drawings, a first embodiment container comprises an outer shell made in sheet steel and an inner shell. The outer shell 1 comprises tube 2 having four side walls, the tube being assembled from four panels, each having a substantially flat side portion 3, a corner portion 4 and a lip 5 adjacent the corner portion. Each panel, in view from one end, therefore is substantially in the shape of a j. Because the primary object of the construction is to provide a container which is relatively cheap, the sheet steel outer shell should be made quite thin, so long as it has sufficient rigidity to hold its shape, when the inner shell is filled with the liquid, powder or grannules to be transported, in a particular example, where the outer shell 10 is approximately a 1 940087 - 12 ~ metre cube, the sheet steel plate used for the outer shell may be of 20 S.W.G.

The walls of the outer shell 10 are constituted by four nearly identical panels 12 and 14, each of which when seen in end view comprises a j shaped member, each arm of the j fonning one side wall of the outer shell 10. At each of the corners, there is a diagonal or angled formation corner portion 16, which in the case of a l metre cube container may for instance be 80 millimetres in width. This angling of the corners adds considerably to the rigidity of each of the arms·' and also to the rigidity of the finished shell 10.

In figures 1 and 6, corner fittings 90 are shown attached to the chamfered corner panels of the outer shell at the bottom end, to allow the container to be secured by screws to a pallet 92.

The two panels 12 and 14 are brought together, so that a first seam of the first panel engages a second seam of the second panel. As a result of joining the two panels 12 and 14 together there is formed a generally rectangular prismatic tube, which is open at the top and bottom. A lid 18 is fitted to the top end of the walls of the outer shell, and secured thereto by the first rolled seam joints.

The formation of the first rolled seam joint for the lid 18 is shown in figures 3 and 4. It will be understood that in other embodiments, a further rolled seam joint for the bottom may be formed in the same manner. The top marginal portion of each panel of the outer shell is rolled to produce a double thickness seam 20 parallel t-94 0 0 8 7 - 13 with, but joggled inwardly of the main side wall portion 6 of the panel, and an upstanding flange 22 parallel with the seam 20, but with a narrow socket 24 between the seam 20 and the flange 22. As shown in figure 3, part of the flange 22 projects above the top end of the seam 20.

The lid 18 has a downwardly depending lip 26 which can be pressed into the socket 24 (see figure 4). The lip 26 may be a tight fit in the socket 24 so that it is retained therein, or the joint may be rolled after the lip is inserted to close the socket and cause the lip to be gripped tightly. In any case, after the lid has been fitted, the projecting part of the flange 22 is turned over as indicated by the dotted line in figure 4 to close on to the top of the lid.

The first rolled seam joint not only holds the lid securely on the tube of the outer shell 10, it also reinforces the walls of the outer shell. Moreover, it ensures that there are no sharp edges on the joint of the lid and the tube.

The construction shown in figures 3 and 4 provides a permanently attached lid. Sometimes, a detachable lid may be required, and for this purpose, the rolled seam joint shown in figure 5 is employed. Initially the walls of the outer shell are formed with the seam 20 and flange 22 as shown in figure 3. A rectangular support frame is provided comprising four support elements 30 each of which is made of sheet material bent into an L shaped crosssection, one arm of the L forming a lip to fit in the socket 24 of the joint. The support frame fits inside the top end of the tube of the outer shell as shown in figure 5, but of course it only covers the outer marginal portion of the open top and of the tube. The projecting part of 940087 - 14 the flange 22 is bent over on to the top arm of each support element.

At spaced locations around the support frame, holes are formed through the frame and a nut 32 is welded to the underside of the frame in alignment with each hole. The lid 18a is somewhat larger than the lid 18, so that its lip 26a fits over the outside of the flange 22. A series of holes is formed through the lid at positions aligned with the holes in the support frame, and cup-headed screws 34 are used to secure the lid to the support frame. The lid can be detached by first removing these screws.

It will be appreciated that once the floor and lid are fitted into the walls of the outer shell, that shell assumes a greater rigidity than is provided by the walls themselves. For all practical purposes, the outer shell can be regarded as a rigid rectangular prism, although in fact, because of the very thin walls, it may be capable of sustaining slight bending. Some or all of the walls may be slightly dished or formed with ribs, as a means of provided greater rigidity if required.

Referring to figures 6 and 7 of the accompanying drawings, there is shown the walls of the outer shell tube in exploded view. The outer shell comprises four panels, each comprising a side portion 100, a corner portion 101, an edge portion 102, and corner fitting 90. At a first vertical edge 103 of the panel, there is provided a first vertical seam 104. At a second vertical edge 105 of the panel is provided a second vertical seam 106.

Referring to figure 8, an arrangement in which a first vertical seam 104 of a first panel is engaged with a second vertical seam 105 of a second panel is shown. 940087 - 15 The first vertical seam of the first panel comprises a first lip 202 and an outer membrane 203. The second vertical seam comprises a second lip 204, and a second outer membrane 205.

Referring to figure 9 of the accompanying drawings, the assembly of figure 8 is shown from above, after the first and second seams have been compressed together, for example by hammering the engaged seams. The first lip 202 compresses the second lip 204 between itself and the outer membrane 203 of the first panel, and the second lip 204, compresses the first lip 202 of the first panel between the second lip and the outer membrane 205 of the second panel, forming a rigid connection between the first and second panels.

The outer shell is assembled from four panels as follows. The first seam 104 of the first panel is engaged length wise with the second seam of the second panel, by inserting a marginal lip of the first seam into the socket of the second seam, and inserting the marginal lip of the second seam into the socket of the first seam. The combined seams are then hammered flat, so that the lip of the first seam is gripped between the lip of the second seam, and the front face of the panel.

The tube is assembled by connecting four panels together, each panel having a first and second seams as described above. The first seam of the first panel is engaged with the second seam of the second panel, and the seams are then compressed together, for example by hammering, to form a first rigid compressed seam joint. The first seam of the second panel is then engaged with the open second seam of a third panel, and the combined seams are hammered together to form a second compressed 940087 - 16 seam joint. The second seam of the fourth panel is engaged with the first seam of the third panel, and the seams are compressed together to form a third compressed seam joint. The first seam of the fourth panel is engaged with the second seam of the first panel, and the seams are compressed together, to form a fourth compressed seam joint. Once all four compressed seam joints have been formed and all four panels have been connected together, the four panels comprise the rigid outer shell.

An advantage of the compressed seam joints as compared to prior art welded edges is that, where the panels are galvanised steel, the galvanization is not removed. This feature is important to comply with hygiene regulations where the containers are used for transport of food stuffs and removes the need for painting the containers, as occurs with prior art containers. Further, the only tools required for joining the compressed seams is a hammer, and no welding equipment is necessary, thus allowing assembly of the outer shell at a wide range of locations as compared with prior art welded construction containers.

A method of manufacturing one of the panels as described above will now be described.

A sheet of rigid material, eg. 20 S.W.G. galvanized steel, is cut into rectangular form. The rolled seam joint as shown in figure 3 of the accompanying drawings is formed along a horizontal edge by bending and crimping a horizontal edge of the sheet. A first open seam is then formed along a first vertical edge of the sheet, the first vertical edge being adjacent to the first horizontal edge, by passing the first vertical edge through a seam turning machine, which turns over a lip at the first vertical edge 4 0 0 8 7 - 17 to form an open seam as shown in figures 7 and 8. The sheet is then turned round and a second vertical edge, opposite the first vertical edge and adjacent the horizontal edge, is fed through the lip turning machine, to turn an outwardly facing lip at the second vertical edge, as shown in figure 7 and 8.

A plurality of creases 150 are formed in the sheet to provide rigidity.

The sheet material is bent about a first elongate bend line 151. The first bend is formed between the first and second vertical edges, and nearer the second vertical edge than the first vertical edge to form the side wall panel 100 and the corner panel 101. The second bend lies parallel to the first and second vertical edges and perpendicular to the horizontal edge.

A further bend along a second elongate bend line 170 is then formed between the first bend and the second vertical edge, thus forming the edge panel 102 adjacent the corner portion 101.

Thus, a panel is formed comprising a substantially flat side wall panel 100, and angled corner panel 101, and an edge panel 102, disposed in the plane substantially perpendicularly to the side panel 100. The corner panel 101 is disposed in a plane which is approximately at 40° to the plane of the edge panel and to the plane of the side panel 100. The plane of the side panel 100 is substantially perpendicular to the plane of the edge panel 102. 940087 - 18 A corner fitting 90, comprising an angle bracket, is then fitted to a lower end of the upright corner panel by friction bolts, for example huck bolts.

In addition to the above, another rolled seam joint may be formed on a lower horizontal edge of the panel, in addition to the rolled seam joint on the upper horizontal edge.

In one embodiment, the inner shell comprises a cylindrical rigid plastics bottle, having a neck which opens out into the opening 11 on the lid.

The inner shell 20 (see figures 2, 11 and 12) may comprise a large plastics bag, with very flexible walls. In this particular construction, the inner shell is made from cross-laminated high and low density polyethylene films. Such film is marketed for exampie by Van Leer Flexibles of Poole under the Trade Mark VALERON. Essentially, cross-laminated film is formed from a plurality of film sheets in some or all of which, the molecular structure has been orientated, but the sheets which are joined together to form a laminate have their molecules orientated in different directions (for example at 90° to each other). The plurality of sheets are brought together during manufacture, so as to produce what is in effect a single sheet or film of very considerable strength. In the particular construction which is being described, the inner shell 40 is made from a multiple laminate material comprising: a layer of low density polyethylene 125 microns thick; a layer of low density polyethylene 5 to 10 microns thick; a layer of high density polyethylene 37.5 microns thick; a layer of low density polyethylene 5 to 10 microns 4 0 0 8 7^. - 19 thick; a layer of high density polyethylene 37.5 microns thick.

At least the two high density polyethylene layers have their molecules orientated in directions which are inclined with respect to the direction of orientation of the molecules in the other of these two layers. In any case, in order to handle materials having specific gravity up to 1.4, the inner shell 40 should be made of polyethylene film between 150 and 250 microns thickness. On the one hand, the thickness of the film will be determined by the strength required to hold the considerable quantity of material which can be accommodated in the inner shell, but on the other hand, the material used for the construction of the inner shell should be as thin as possible in order to minimise the expense of manufacture.

The inner shell 40 may have heat sealed seams, and when expanded (that is opened out to its maximum size) it is generally a rectangular prism, capable of nearly filling the outer shell 10. The material which is to be contained has to be held in the inner shell 40, and it is generally desirable to avoid creasing of the inner shell 40, when the latter is expanded, because of the possibility of material lodging in the creases. This of course is particularly true of the bottom side of the inner shell. As illustrated in figure 6, top and bottom planar sustaining elements 50 and 52 are secured to the top and bottom sides of the inner shell 50. Each of these sustaining elements 50 and 52 is made in card, which whilst it assists in preventing creasing of the side to which it is secured, is nevertheless relatively cheap. It will be noted, that the top sustaining element 50 extends over substantially the entire top surface of the expanded 940087 - 20 flexible inner shell, whereas the bottom sustainer 52 terminates some distance from the left hand side of the container as seen in figure 11. The sustaining elements 50 and 52 are preferably attached to the inner shell 40 by adhesive. This can readily be achieved, by coating the underside of the top sustaining element 50 and the top side of the bottom sustaining element 52 with adhesive, and then expanding the inner shell 40 by blowing air into it, until its top and bottom sides engage with their respective sustaining elements under the internal pressure provided by the air which has been blow into the shell. This is sufficient to produce the necessary adhesion of the sustaining element to the shell. It should emphasized, that whilst the sustaining element 52 prevent creasing of the inner shell 40, they do not give that shell a general rigidity, and it is still capable of collapsing upon itself. It has been found possible in some instances to dispense with the top element 50 and to rely on the bottom element 52.

In one embodiment, a moulded plastics inlet adapter 64 is provided which is illustrated in figure 2. It should first be noted that an inlet opening 60 is formed in the centre of the lid 18, but part of the lid around the opening 60 is dished inwardly as shown at 62. The adapter 64 is a ring which lies on the dished part of the lid, and a lip 66 which projects through the hole 60. Internally, the adapter 64 is formed with a single turn screw-thread 68. A clamping collar 70 fits on the outside of the lip 66 and co-operates with the adapter. As clearly shown in figure 2, the marginal portions of the lid 18 around the inlet hole 60 and of the inner shell 40 around its inlet hole are clamped between the adapter ring and the clamping collar and thee assembly is completed by ^9 * ϋ ο β ι - 21 rivets 72. Thus, the inner shell 40 is secured to the outer shell at the inlet.

A moulded plastics filler cap 74 has a single turn threaded part 76 which enables it to be quickly attached to or detached from the adapter 64.

In the embodiment, in which the inner shell comprises a large bottle, the inlet may comprise a circular aperture in the lid, as shown in figure 10. In this embodiment, the perimeter of the aperture has a rubber or plastics protective safety strip 300 of generally u shaped profile slotted onto the perimeter to prevent contact with the sharp perimeter edges.

Referring to figures 12 and 13, a moulded plastics outlet pipe 36 has a screw-threaded portion which passes through a hole in a lower part of one wall of the inner shell 40, and a moulded plastics nut or cap 38 fits on the part of the outer pipe 36 which projects inside the shell 40, whereby part of the shell 40 around an outlet hole in that shell is nipped between a collar 80 formed integrally with the outlet pipe 36 and the nut 38. It will be appreciated that it is necessary to fit the nut 38 on the outlet pipe 36, by gaining access to the interior of the inner shell 40 through the inlet opening covered by the filler cap 74. As indicated in figure 11, the outlet pipe 36 is located above that portion of the bottom side of the inner shell which is not attached to the bottom sustaining element 52.

The outlet pipe 36 may be provided with any known form of valve, which will enable liquid, semi-liquid, powdered or granular material, to be drained out of the inner shell 40 when required. 9-» 0 08 7 - 22 An outlet opening 42 is fonned in one wall of the outer shell 10, near to the bottom of that wall, to allow access to the outlet pipe 36. It is desirable however to provide support for the outlet pipe 36, and to prevent easy access to the inner shell 40 through the opening 42 so that pointed articles cannot be inserted through the opening 42. One method of achieving these desired features is to provide an inner cover such as that illustrated in 44 in figure 13, this inner cover being made of sheet steel material, and secured either to the floor of the outer shell 10, or to the wall of that shell in which the opening 42 is formed. Also, as illustrated in figure 13, there may be a Z-shaped member 46 which performs the dual function of providing a platform on which the outlet pipe 36 can rest, and a physical barrier closing the opening through the cover 44 under the outlet pipe 36.

As an alternative to the box-like formation of the cover 44, shown in full lines in figure 13, it may be extended across the full width of the outer shell as indicated in chain-dotted lines.

When the container is to be used, the filling cap 74 is removed, and liquid or other flowable material such as powder can be fed through the inlet into the inner shell 40. That shell expands as it is filled but its dimensions are such, that even when fully filled, it does not exert any severe outward pressure on the walls of the outer shell 10. Since it is desirable to make the outer shell as close a fit as possible around the inner shell however, and bearing in mind that the inner shell is flexible, the inner shell may in fact engage with the outer shell at certain positions. 940087 - 23 When the container is to be emptied, it is only necessary to open the tap or valve in the outlet pipe 36. It is however desirable to remove the filling cap 74 before attempting to empty the container.

Referring to figure 14 of the accompanying drawings, a modified outlet pipe 400 is shown, in a modified housing 401, the housing being attached to the outer container. The modified pipe outlet 400 comprises an elongate tube 402 having a conventional ball valve (not shown) inside the tube, operated by the lever 403. As the ball valve is operated by twisting the lever about a rotational axis which is transverse to a main axis of the outlet pipe, turning the lever causes twisting of the pipe. As this can be problematic where the outlet is connected to a bag, the housing 401 is provided to secure the outlet pipe to the outer container.

The housing 401 comprises a base portion 410 which supports a first upright support 411 and a second upright locking mechanism 412. A substantially horizontal bridge piece 413 is pivotally secured to the upright bracket 411 at one end, and has a second end which engages the locking mechanism 412. The locking mechanism may itself be pivotally attached to the base portion 410 and in use, insertion of the pipe into the housing may be as follows The housing is positioned in an open position in which the bridge portion is vertical, and the locking bracket 412 lies horizontal. The ball valve lever 403 is twisted to be in line with an aperture 420 in the bridge portion, so that the bridge portion can drop over the lever and onto the pipe 400. The locking mechanism 412 is then pivoted to an upright position, such that it engages one end of the bridge member, blocking the bridge member 0 08 7 J - 24 in position. Thus the bridge member is releasable and lockable to keep the pipe in position, or release the pipe as appropriate.

A further improvement to the pipe, which is made of a plastics material for example polyethylene, which is particularly advantageous where the container is to be used for carrying foodstuffs, if the provision of a screw threaded end cap 500 for sealing the end of the pipe. The end cap screws into the end of the pipe and is provided with a plurality of holes 501, through which a metal sealing wire may be attached, the other end of the wire being attached to the container or some other solid object, to prevent un-screwing of the cap. This is advantageous in ensuring that, for customs purposes the Customs Officer can check that the cap has not been removed, by checking that the wire is still sealed.

It will be appreciated that various constructional alternatives may be employed without departing from the inventive concept. For instance, the outlet pipe may be located in the bottom of the inner shell, so that the container is emptied through the bottom instead of out through one side wall. Indeed, for some purposes, the outlet pipe may be omitted altogether, if the material to be transported can be sucked out through the inlet. It will be appreciated that if the outlet pipe can be located either in the bottom of the inner shell 40, or omitted altogether, then the bottom sustaining element 52 can be extended across the full width of the outer shell, because it is no longer necessary to leave an unsustained flexible portion of the inner shell to fit around the bulkhead or cover 44. 4 ο ο 7 940087^ In the specific example described above, the inner shell is flexible. It should be understood however, that rigid inner shells may be employed, in which case they can either be secured to the inlet opening in similar fashion to that described with reference to figure 2 of the drawings, or alternatively, can be free standing on the floor provided by the bottom of the outer shell. In the case of a free-standing inner shell or bottle, a screw cap or closure is provided on the inner shell and an inlet hole is formed centrally in the lid of the outer shell to give access to the screw cap or closure.

The rigid inner shell may be provided with an outlet with a tap as described with reference to the flexible inner shell.

When a larger capacity container is required, such as a 2000 litre container, the outer shell may comprise two shells such as that described above, placed one on top of the other, but with only a single lid and a single floor (ie. there is no floor in the upper shell and no lid in the lower shell). To give the require degree of rigidity, a steel strap say 3 inches wide, is welded to the outside of the two shells, the strap surrounding the shells and extending above and below the horizontal joint.

The above constructions and methods of manufacture allow the outer shell of the container to be supplied in kit form for transportation. Each kit comprises four panels as described above with reference to figure 6, which can be flat-packed for transport; a lid; and a pallet. The containers may thus be transported and stored in kit form which is space and cost efficient and easily assembled on site immediately prior to filling with flowable material. Assembly of the containers is 940087 - 26 relatively un-skilled and requires minimum tools, eg. a hammer to compress the seam joints and to bend over the rolled seam joint.

Claims (5)

1. A method of manufacturing a panel of a container for transporting and/or storing a flowable material, the container comprising a plurality of side wall panels, each panel formed of a substantially flat sheet of rigid material and having a main side wall portion, the method comprising the steps of, for each panel: (i) forming an upper seam along an upper edge of the sheet; (ii) forming a first seam along a first edge of the sheet; (iii) forming a second seam along a second edge of the sheet, said second edge being opposite said first edge and said upper seam being transverse to each of said first and second seams.

2. A method according to claim 1, in which a said panel includes a corner portion located adjacent the side wall portion, and further comprising the steps of: (iv) forming an elongate bend in the sheet along a line which lies between said first and second seams, and nearer said second seam than said first seam, such that the main side wall portion is defined between said bend line and said first seam, and the corner portion is formed between said bend line and said second seam; (v) attaching a foot member to the corner portion, said foot member attached to said sheet material by at least one fixing device; and l 940Q87 - 28 (vi) forming a second bend along a second elongate bend line between the first bend line and the second seam, to form an edge portion adjacent said corner portion, the second seam being carried on said edge portion.

3. A method of assembling a container from a plurality of panels manufactured according to the method of any one of claims 1 to 3, the method of assembly comprising: engaging a said first seam of a first said panel with a second seam of a second said panel and compressing together said seams to form a first compressed seam joint; engaging a first seam of the second panel with a second seam of a third said panel and compressing said seams together to form a second compressed seam joint; engaging a first seam of the third panel with a first seam of a fourth panel and compressing said seams together to form a third compressed seam joint; engaging a first seam of the fourth panel with the second seam of the first panel and compressing said seams together to form a fourth compressed seam joint, wherein said first to fourth panels are joined together to form a tubular shell structure.

4. A method according to claim 3, further comprising the step of: (vii) closing the tubular shell structure by fitting an end closure member comprising a sheet of material having a peripheral downwardly - 29 depending lip, inserting the downwardly depending lip into a socket of the upper seam, and bending a portion of the upper seam over the periphery of the lid to enclose the downwardly 5. Depending lip in the upper seam.

5. A panel manufactured in accordance with claim 1 or 2, or a container assembled in accordance with a method as claimed in claim 3 or 4.