GB1583693A - Containers having an inflatable tubular seal - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO CONTAINERS HAVING AN INFLATABLE TUBULAR SEAL (71) We, AIRFLEX CONTAINERS LIMITED, a British Company, of Bruns- wick Road, Cobbs Wood Industrial Estate.

Ashford, Kent, and CHRISTOPHER DANIEL DOWLING HICKEY, a British Subject, of 5 Heathside, Hinchley Wood.

Esher, Surrey, do hereby declare the invention, for which we pray that a patent may be granted to us. and the method by which it is to be performed to be particularly described in and by the following statcment:- This invention relates to containers of the kind having a base with a load-carying surface and a cover which is sealed to the base by an inflatable tubular sealing mcmber. Typicallv the base has an impermeable load-carrying surface. and the cover is a flexible impermeable envelope to cover goods on said base. which envelope is sealed to the base by an inflatable tubular sealing member extending around the periphery of the envelope to hold the envelope in airtight engagement against a part of the base assembly.

Containers of this kind are used bv putting the envelope of impermeable mate- rial over a load on the air-impermeable base and then sealing the periphery of the envelope to the base bv an airtight seal: the space within the envelope may then be partially evacuated so that the reduced pressure holds the envelope tightly down onto the base: if the envelope is flexible it is drawn down onto the load and so holds the load firmlv onto the base. In some cases the region inside the envelope may he press rises. e.g. with dry air or an inert gas.Such packaging systems find particular appl ica- tion for loads which mav haze to he trins- ported but which may also have to he stored for long periods. By evacuation. the en velopc plOVi(lCS the required restraint on goods during transport and also serves to protect the goods during st()rge. Both for transport and for storage, it is necessary that the envelope should be sealed to the base in an airtight manner.For this purpose, it is known to use an inflatable tubular seal.

Such a seal may be formed as a tube integral with or secured to the periphery of the envelope as described for example in Specification No. 1286544 or it may be a separate tube either fitting in or secured to the base.

Very conveniently the periphery of the envelope is put within a slot or groove extending around the base and the aforementioned tube inflated to seal the periphery of the envelope against one or both walls of the slot or groove. For example. the tube may be placed within the slot or groove and the periphery of the envelope then put within the slot or groove between the tube and one side wall of the slot or groove: the tube is then inflated to press the envelope against that side wall.

It has been found that. particularly with long-term storage. there may be leakage from the tubular seal. for example a slow leak through the inflation valve. so that.

after a long term. the tube has lost so much pressure that the seal is no longer airtight.

It is one of the objects of the present invention to provide an improved form of sealing for such a container.

According to this invention. a container for goods comprises a base with an impermeable load-carrving surface, a flexible imperinetble envelope and a pressure surface against which the periphery of the envelope is to be sealed to form a vacuumtight container for goods enclosed between the envelope and the impermeible surface of the base. wherein, for sealing the periphery of the envelope 'tgainst said press ure surface. there are provided two separate sealing tubes which are separately inflatable and tube holder means locating said tubes with respect to said surface so thit each tube extends arouncl tlte peripheral portion of the envelope. one further inwardly from the edge thereof than the other each inflatable tube arranged, on inflation, to force the adjacent part of the envelope towards said pressure surface. This pressure surface conveniently is one wall of a slot or groove on said base.Preferably said wall has a rib or other projection extending along its length in each of the regions where the envelope is forced by a tube against the wall so as to give a localised pressure line and thereby giving a tight seal.

In referring to a base with an impermeable surface, it will be understood that the impermeable surface might be formed integrally with a rigid base or it might be constituted. for example. by a further sheet of flexible material over a load-bearing base. If such a further sheet is provided.

conveniently the peripheries of the two sheets are sealed together to form the airtight container by putting the peripheries of both sheets in said slot or groove and then inflating said tubes. In referring in this specification to the pressing of the part of the envelope towards said wall or other pressure surplice. it will be understood that this includes arrangements in which, if a further sheet is used over the base. the peripheries of both sheets may together be pressed against said will or other surface.

The aforementioned slot or groove may be an integral part of the base or attached thereto in an airtight manner or. if a further sheet is used. it may merely be carried on said base.

In the known way provision may be made for partiallv evacuating the interior of the envelope so that the latter is held down by air pressure to restrain goods On said base.

Provision may also be made for inflating the envelope, for example with an inert gas or with dry air. The base may conveniently be a pallet having apertures to accept the prongs of a fork-lift truck.

If the aforementioned wall forms one side of a groove or slot in the bise. the aforementioned tubes may be located in said slot or groove. In order to facilitate proper location of said tubes in such a groove or slot. said tube holder means convenientl comprises a removable beat- ing memher which holds the tubes and into which the tubes may be assembled hefore the locating member is put in said slot or groove. Such a tube holder is described and claimed in the specification of co-pending Application No. 4987/77 (Serial No.

l583fi92) out of which the present applici- tion is divided. By this construction. it becomes readily possible to insert or remove the sealing tubers from the assembly yet the sealing tubes are accurately located so that they can al'l'lv T pressure to the envelope opposite the aforementioned ribs or projec- tions.

The provision of a tube holder along the length of the tube or tubes and extending around the major part of the periphery of the tubular seal constrains the expansion of the tube and localises it in the required position.

The following is a description of two embodiments of the invention, reference being made to the accompanying drawings in which: Figure 1 is a diagrammatic cross-section through part of the sealing system for sealing an envelope of flexible impermeable material to the base of a container; and Figure 2 is a view similar to Figure I of another construction of container.

The embodiments shown in Figures 1 and 2 are also described and claimed in the specification of the aforementioned Application No. 4987/77 (Serial No. 1583692) out of which the present application is divided.

Figure 1 shows part of the peripheral portion 10 of a flexible sheet of impermeable material. for example butyl rubber, which is to be sealed against a pressure plate 11 forming an upright side wall of a tray 12 extending over and forming part of the base of a container 13. The trav may be impermeable or the container may be impermeable or they may be covered with an impermeable sheet in order to form an airtight support surface for carrying goods. The goods may rest on this surface or be carried above it in the known way, e.g. on shockabsorbing mounts. In the known way also this base may be arranged as part of a pallet having openings for handling by a fork-lift truck.Provision is made also in the known way for evacuating the region between the impermeable base and the envelope andior for pressurising this region. for example with an inert gas or drv air.

The present invention is concerned more particularly with the sealing of the periphery of the envelope 1() against the pressure plate II. This pressing plate is supported at intervals along its length by stiffeners 14 to enable it to withstand the pressures to be applied os described hereinafter. Sealing is effected. in this particular embodiment.

along the length of two ribs 15 formed in the side wall II, these ribs extending along the whole length of the side wall, which side wall extends around the whole of the container just inwardly from the periphery thereof. The base of the container has a further upright wall 16 spaced away from the pressure wall I I so that the two walls 11.

16 form a channel or groove lying between these upright wills. Within this channel or groove is positioned a rigid metal or plastics element 2() having two chambers 21 extending along the length of the element, which element may be an endless element or conveniently is formed in a number of sections which together extend along the whole length of the endless channel or groove. In each of these chamber is located an inflatable tube 22 of resilient material. In the embodiment of Figure 1 the upper one of these tubes is uninflated and, in this condition, it is of non-circular form. The tube is shaped so that it is closely embraced over a substantial part of its circumference by the wall of the chamber 21.This chamber has an opening 23 opposite one of the aforementioned ribs 15 and the part of the tube 22 adjacent this opening 23 is shaped so that, in the uninflated condition, it lies just inwardly of the outer surface of the tube holder as shown for the upper tube in the drawing. The other tube is a similar tube but is shown in the inflated condition; when so inflated, the part adjacent the opening in the chamber bulges outwardly as shown at 25 to apply pressure to the aforementioned sheet 10 so that it is compressed between this tube and one of the ribs 15 thereby sealing the envelope against that rib.

With the tubes in the deflated condition.

the tube holder 2() and tube 22 can be withdrawn from said slot or groove and it becomes readily possible to remove and replace the tubes. Each tube is provided with a separate inflation svstem. Convenientlv inflation valves as shown at 26. 27 extend outwardly through an upright slot in the aforementioned outer wall 16 to permit withdrawal of the tube holder and tubes with these valves. Because the tubes are confined within chambers closely embracing the tubes over the greater part of the periphery. it is possible to use higher pressures than has heretofore been the practice in tubular seals for containers and hence to get higher pressure exerted on the sheet 1() pressing it against the rib in the pressure wall.The use of this form of tube and tube container thus. in itself, enables an improved seal to be obtained. Bv providing two separate sealing tubes however as shown in the diagram. an effcctive seal is still maintained cven if one of the tubes should lose pressure.

Although specifically shaped sealing tubes have been illustratcd in Figure 1.

other shapes may be used such as cvlindric'iI or ovoid or lay-flat tubing.

Figure 2 illustrates a modification of the container of Figure 1. The same reference numerals are used to indicate corresp)nding components and, in the following description. mention will he made only of the distinctive features. In this embodiment, the base 13 of the container necd l()t be impermeable to air as it is covered by a flexible impermeable sheet 30 the peripher- al edge of which extends around the top of the wall 11 to lie between that wall and the cover sheet 1(). I'hus. when the two tubes 22 are inflated. the sheets are pressed together around their complete peripheries to seal the container.

In Figure 2, cylindrical section tubes 22 are shown. The upper one, shown uninflated, is a loose fit in its chamber 21. The lower tube 22 is shown inflated; where it lies inside the chamber 21, it is restrained to the shape of the chamber wall but it bulges at 25 through the opening to press the sheets 10, 30 together.

WHAT WE CLAIM IS: 1. A container for goods comprising a base with an impermeable load-carrying surface, a flexible impermeable envelope and a pressure surface against which the periphery of the envelope is to be sealed to form a vacuum-tight container for goods enclosed between the envelope and the impermeable surface of the base, wherein, for sealing the periphery of the envelope against said pressure surface. there are provided two separate sealing tubes which are separately inflatable and tube holder means locating said tubes with respect to said surface so that each tube extends around the peripheral portion of the envelope, one further inwardly from the edge thereof than the other. each inflatable tube arranged. on inflation. to force the adjacent part of the envelope towards said pressure surface.

2. A container as claimed in claim I wherein said pressure surface is one will of a slot or groove on said base.

3. A container as claimed in claim 2 wherein said wall has a rib or other projection extending along its length in each of the regions where the envelope is forccd by a tube against the wall so as to give a localised pressure line and thereby giving a tight seal.

4. A container as claimed in either claim 2 or claim 3 wherein said impermeable surface is constituted bv a further sheet of flexible matelial over a load-bearing base and wherein the peripheries of the two sheets are put in said slot or groove hefore said tubes are inflated to seal the sheets together.

A A container as cItimed in any of the preceding claims wherein means are pro- vided fol partitIly evacuiting the interior of the envelope so that the latter is held down by air pressure to restrain Foocls on said base.

6. A container as claimed in any of the preceding claims and wherein said pressure surface is a wall forming one side of a groove or slot in the base. and wherein said tubes are located in said slot or groove.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. sections which together extend along the whole length of the endless channel or groove. In each of these chamber is located an inflatable tube 22 of resilient material. In the embodiment of Figure 1 the upper one of these tubes is uninflated and, in this condition, it is of non-circular form. The tube is shaped so that it is closely embraced over a substantial part of its circumference by the wall of the chamber 21. This chamber has an opening 23 opposite one of the aforementioned ribs 15 and the part of the tube 22 adjacent this opening 23 is shaped so that, in the uninflated condition, it lies just inwardly of the outer surface of the tube holder as shown for the upper tube in the drawing.The other tube is a similar tube but is shown in the inflated condition; when so inflated, the part adjacent the opening in the chamber bulges outwardly as shown at 25 to apply pressure to the aforementioned sheet 10 so that it is compressed between this tube and one of the ribs 15 thereby sealing the envelope against that rib. With the tubes in the deflated condition. the tube holder 2() and tube 22 can be withdrawn from said slot or groove and it becomes readily possible to remove and replace the tubes. Each tube is provided with a separate inflation svstem. Convenientlv inflation valves as shown at 26. 27 extend outwardly through an upright slot in the aforementioned outer wall 16 to permit withdrawal of the tube holder and tubes with these valves. Because the tubes are confined within chambers closely embracing the tubes over the greater part of the periphery. it is possible to use higher pressures than has heretofore been the practice in tubular seals for containers and hence to get higher pressure exerted on the sheet 1() pressing it against the rib in the pressure wall.The use of this form of tube and tube container thus. in itself, enables an improved seal to be obtained. Bv providing two separate sealing tubes however as shown in the diagram. an effcctive seal is still maintained cven if one of the tubes should lose pressure. Although specifically shaped sealing tubes have been illustratcd in Figure 1. other shapes may be used such as cvlindric'iI or ovoid or lay-flat tubing. Figure 2 illustrates a modification of the container of Figure 1. The same reference numerals are used to indicate corresp)nding components and, in the following description. mention will he made only of the distinctive features. In this embodiment, the base 13 of the container necd l()t be impermeable to air as it is covered by a flexible impermeable sheet 30 the peripher- al edge of which extends around the top of the wall 11 to lie between that wall and the cover sheet 1(). I'hus. when the two tubes 22 are inflated. the sheets are pressed together around their complete peripheries to seal the container. In Figure 2, cylindrical section tubes 22 are shown. The upper one, shown uninflated, is a loose fit in its chamber 21. The lower tube 22 is shown inflated; where it lies inside the chamber 21, it is restrained to the shape of the chamber wall but it bulges at 25 through the opening to press the sheets 10, 30 together. WHAT WE CLAIM IS:

1. A container for goods comprising a base with an impermeable load-carrying surface, a flexible impermeable envelope and a pressure surface against which the periphery of the envelope is to be sealed to form a vacuum-tight container for goods enclosed between the envelope and the impermeable surface of the base, wherein, for sealing the periphery of the envelope against said pressure surface. there are provided two separate sealing tubes which are separately inflatable and tube holder means locating said tubes with respect to said surface so that each tube extends around the peripheral portion of the envelope, one further inwardly from the edge thereof than the other. each inflatable tube arranged. on inflation. to force the adjacent part of the envelope towards said pressure surface.

2. A container as claimed in claim I wherein said pressure surface is one will of a slot or groove on said base.

3. A container as claimed in claim 2 wherein said wall has a rib or other projection extending along its length in each of the regions where the envelope is forccd by a tube against the wall so as to give a localised pressure line and thereby giving a tight seal.

4. A container as claimed in either claim 2 or claim 3 wherein said impermeable surface is constituted bv a further sheet of flexible matelial over a load-bearing base and wherein the peripheries of the two sheets are put in said slot or groove hefore said tubes are inflated to seal the sheets together.

A A container as cItimed in any of the preceding claims wherein means are pro- vided fol partitIly evacuiting the interior of the envelope so that the latter is held down by air pressure to restrain Foocls on said base.

6. A container as claimed in any of the preceding claims and wherein said pressure surface is a wall forming one side of a groove or slot in the base. and wherein said tubes are located in said slot or groove.