GB2356211A

GB2356211A - Flexible gas impermeable pressure vessel

Info

Publication number: GB2356211A
Application number: GB0005618A
Authority: GB
Inventors: Alex Burnup
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-11-10
Filing date: 2000-03-10
Publication date: 2001-05-16
Anticipated expiration: 2020-03-10
Also published as: GB0005618D0; GB2356211B; GB9926514D0

Abstract

A pressure vessel comprises a body 10, an opening in the body 14 and a door 18 for closing the opening in the body, the door having a gas inlet valve and a gas outlet valve and the body having an inner gas impermeable layer (20, Fig 4) and an outer fabric layer (22, Fig 4) made from flexible plastics material. The body may be cylindrical while the opening which may be provided at one end may have a collar 16 around it. The fabric layer may be woven or knitted from strips of material such as polyester arranged into weft rings spaced along the length of the vessel and longitudinally extending warp strips. The pressure vessel may be used as a portable decompression chamber, a subsea lifting bag or a pressurised medical enclosure.

Description

2356211 PRESSURE VESSEL This invention relates to a pressure vessel, and

in particular to a pressure vessel that can maintain a considerable internal pressure but can also be compressed and folded into a small volume when not in use.

It is a hazard of diving that too quick a return to the surface can cause various very serious medical conditions the commonest of which is an attack of the "bends" which at best is extremely painful and can cause permanent injury or even death. If a diver has returned to the surface too quickly it is important that he be placed in a decompression chamber within a few minutes or as soon as possible and subjected to a controlled programme of pressure change to mitigate the effects of the bends. Such decompression chambers are fixed professional installations using large steel cylinders having a door at one end, and they are few and far between. As diving takes place almost anywhere where there is a suitable depth of water, it is unlikely that a diver threatened with the bends is sufficiently close to a decompression chamber to avoid becomingvery ill and incurring at least some injury.

It is an object of the present invention to provide a pressure vessel that is portable and can accompany a group of divers to the diving site and be available for use immediately.

The present invention is a pressure vessel comprising a body, an opening in the body 2 5 and a door for closing the opening in the body, the door having a gas inlet valve and a gas outlet valve, and the body having an inner gas impermeable layer and an outer fabric layer made from flexible plastics material.

The fabric layer may be woven or knitted.

The body may be cylindrical with the opening at one end.

Preferably the strips are woven from a man made material such as a polyester.

A flexible collar may be provided round the opening.

The outer layer may have weft rings spaced along the length of the vessel, each weft ring being formed from a strip of said flexible plastics material with its ends fastened together.

The outer layer may have warp strips extending from the interior ofthe vessel over the collar, down the length ofthe vessel, across the other end, up the length of the vessel, over the collar and into the vessel.

An embodiment of the present invention will now be described, by way of example, 2 0 with reference to the accompanying drawing, in which: - Fig. I is a longitudinal eross-section through a pressure vessel according to the present invention; Fig. 2 is a view of the exterior of the closed end of the vessel of Fig. 1; Fig. 3 is a cross-section through the vessel of Fig. 1; and Fig. 4 is an enlarged partial cross section through the open end of the pressure vessel of Fig. 1.

Referring now to the drawings, a pressure vessel according to the present invention comprises a cylindrical body 10 having a closed end 12 and an open end 14. Around the aperture at the open end is a collar 16 which retains a door or lid 18.

The body 12 comprises two layers 20 and 22, the inner layer 20 being gas tight while the outer layer 22 of fabric provides the reinforcement or strength to resist the pressure inside the body. The outer 22 layer is, in this embodiment, woven from strips of plastics material, a polyester, the strips themselves being woven from polyester fibres. Man made materials other than polyester may be used, for example aramide fibres or a polyethylene fibre known as "Dyneema7', and mixtures of such fibres may also be used. Lengths of the strip have their ends sewn together to form weft rings which are placed side by side along the length of the body. The collar 16, formed from polyester fibres wound to form an o-ring, is located at one end of the weft rings. Each warp strip is looped round the collar 16, and is sewn to itself to retain the collar. From the collar the warp strip is woven into the weft rings along the length of the body to its other end where it crosses diametrically to the other side of the body, is woven into the weft rings along the length ofthe body, is looped over the collar 16 and is then 2 0 sewn to itself. At both ends a warp strip may be woven into the weft rings and the resulting friction strengthens the sewn attachment.

The warp strips all cross at the centre of the bottom of the body to provide the necessary strength in this area.

Inside the outer woven layer 22 is the inner gas impervious layer 20 in the form of a loose liner bonded to the interior surface of the woven outer layer. The inner layer consists of a sheet of dense impervious plastics material formed or bonded to the required shape, or 5 a liquid which dries to form an impervious layer, or a woven material impregnated with or coated by a gas impervious material and it extends to the outside of the collar.

The door 18 is rigid and may be made of any material having the necessary strength, such as steel or a reinforced plastics material. The door may be flat but in this embodiment is domed, and around the door's periphery is an inwardly curled flange 24 for engaging the inner lining at the inside of the collar 16 as seen best in Fig. 4.

The door 18 may be provided with a number of fittings depending on the intended use of the vessel; in this embodiment, intended as a portable decompression chamber, the door has an inlet gas valve, a pressure relief valve, a pressure gauge and a gas outlet valve. The outlet valve has a flexible inlet tube extending inside the vessel to its bottom so that it draws gas from the bottom of the vessel and causes a flow of gas from the inlet valve down the length of the vessel.

When not in use the vessel is not pressurised and the body is flexible, light enough to be carried by one person, and may be folded for transport or storage. The vessel is prepared for use as an emergency decompression chamber by being laid out flat to enable a diver to be placed in the vessel with his head at the open end. The collar is distorted to allow the door to be passed into the interior of the vessel, the door is then located with its flange in engagement with the collar, and a supply ofpressurised oxygen or oxygen/gas mixture, which may conveniently be a diver's gas cylinder, is connected to the inlet valve, so that as the pressure in the vessel increases the door is pressed against the collar to establish an airtight 5 seal.

Different inlet valves may be provided to allow the connection of different coupling sizes for different air bottles or other sources of pressurised gas.

A suitable decompression prograrnme, printed on the exterior of the vessel or otherwise associated with it, can then be followed to give almost immediate treatment to the diver and reduce or prevent the injuries that the diver might suffer if left untreated during a lengthy journey to the nearest decompression chamber.

As a pressure vessel as described is capable of high internal pressures while being portable, it may also be used as a pressure bag for lifting heavy objects in situations in which more conventional lifting means such as cranes orj acks cannot be deployed. The embodiment described can have an internal pressure of 150 lbs/sq.in., and can lift up to 100 tons. It also has other engineering applications. 20 The embodiment described may be modified in a number of ways. To facilitate the positioning of an unconscious diver in the vessel it may be desirable to provide means which maintains the shape of the vessel even when it is not pressurised; such means may take the form of tubes located inside or outside the body which when filled with a gas under pressure 25 stiffen sufficiently to hold the vessel in its pressurised shape.

If desired, the door may be hinged on a rigid collar permanently secured to the end of the vessel, and an additional compressible seal may be provided between the door and the collar. Instead of a flange 24 there may be substituted an annular tube welded to a metal door.

Pressure vessels according to the present invention may also have other medical uses such as a low pressure oxygen chamber for pregnant women and, in larger sizes, oxygen pressurised. operating theatres.

Pressure vessels according to the invention need not be cylindrical but may be of other shapes such as spherical. Also doors may be provided at both ends of a cylindrical vessel. If used as an airlock for a larger vessel, the entrance has a soft collar and, at the entry to the larger vessel, a rigid collar is inserted through and engages a soft collar in the larger vessel.

VVhile the layer 22 in this embodiment is a woven fabric it could equally be a fabric assembled by knitting or weaving or double weaving used alone or in combination, or any other method involving the passing of thread or threads or yam or other filaments over and under one or another or through loops to form a webbing or knitted material which has a shape open at one or two positions or more such as a tube with one closed end or a tube with two ends open or a tube with multiple openings or any other shape enclosing a space which can be used as a pressure vessel or part of a pressure vessel.

Claims

CLAIMS 1. A tubular or spherical or any other volumetric shaped pressure

vessel constructed of, a woven or knitted man made fibre material lined with an impervious plastic material with a restrictive opening fonned from an attached tubular flexible collar/ring and hatch which when the opening is deformed allows the hatch to be passed inside, pulled back against the opening and sealed when pressurised and when empty, may be compressed and folded in any direction into a small volume.-Fig 1.

2. A pressure vessel as claimed in any preceding claim where a flexible collar, constructed from a highly flexible non-rigid plastic filament or filaments, fibre or thread formed into a tubular flexible ring, and covered by a woven or knitted cloth, film or binding plastic material, retained by warp lengths that are passed over it and to the inside or outside of the vessel, is provided for the retention of a greater diameter unattached hatch or connector and seal which may be passed to the inside of the vessel by deformation of the flexible opening constructed to include a collar within the neck on which it seats.- Fig 1 3 & 3a.

3. A pressure vessel as claimed in any preceding claim where the warp and weft are attached together only for partial strengthening of the vessel and as a means to retain the shape of the vessel before pressurisation commences when friction between the warp and weft, and the hatch or connector and the collar at the neck in the case of the unattached hatch or connector or the clamping action of the friction resulting from a ring to which the attached hatch, or connector, maintains the integrity of the vessel.

4. A pressure vessel as claimed in any proceeding claim in which the vessel maintains its integrity through friction as pressure is increased within the impermeable plastic liner, or other layer, or body and the hatch or connector and seal are forced against the collar and the various woven layers of materials used in the pressure vessel's construction.- Fig 1 3 & 4.

5. A pressure vessel as claimed in any preceding Claim which is woven or knitted from a narrow fabric made as rings or joined rings of narrow fabric lengths to form the weft whilst the warp of similar material is woven through the weft in a number of single continuous lengths dependent on the diameter or shape required from the inside or outside of the vessel up and over the entry neck collar down one side across the bottom and up the opposite side over the entry collar and back inside or outside the vessel diametrically opposite or to one side or the other from the point that the other end of the warp strand commenced. - Fig 1.

6. A pressure vessel as claimed in any preceding Claim which is woven from narrow fabric where the weft is a continuous length or spiral starting from a closed -9loop and ending in a closed loop, subject to the length and shape of the vessel to be constructed, with the warp woven through the continuous or spiral weft.

7. A pressure vessel as claimed in any preceding claim which is knitted, from a plastic or two or more different plastic materials formed into a yarn, to form any shape required with the neck formed by folding inwards over the collar to be lightly attached to the inside whilst the larger diameter hatch may be passed inside by deforming the neck and collar, in similar fashion to one that is woven, prior to pressurisation which forces the unattached hatch against the neck where friction completes the integrity of the hatch or connector, seal and body of the vessel.

8. A pressure vessel as claimed in any preceding claim where the unattached hatch or connector made from plastic or metal is constructed to a suitable shape with an outer soft flexible plastic seat attached to the hatch so shaped as to seat into the flexible collar covered by the internal impermeable layer or liner at the neck, forming a seal. - Fig 3, 3a & 4.

9. A pressure vessel as claimed in any preceding claim in which the flexible pressure vessel may be equipped with flexible tubes, attached inside or outside the vessel, which stiffen when inflated to cause the flattened and folded vessel to assume that shape to which it has been constructed.

-1010. A pressure vessel as claimed in any preceding Claim where flexible or rigid tubes may be lead through holes made in the hatch for the purpose of the sealed delivery and variation in pressure of a contained gas or gas mixture or liquid or liquid mixture or slurry or any combination of gas liquid and slurry, or to permit electrical or electronic or mechanical cables to pass inside for the purpose of connecting various breathing apparatus or instruments, measuring gauges, communication equipment including microphones, CCTV cameras, medical monitoring and the use of surgical equipment of the key hole variety.

I I Amended claims have been filed as follows CLAIMS:

1. A unit which is a pressure vessel comprising a body having an inner gas impermeable layer and an outer fabric layer made from flexible plastics material with an opening in it Figure I and a door Figure 1.18 equipped with gas inlet and outlet valves.

2. A unit according to claim 1which can be inflated to a considerable pressure to recompress one person to a pressure considered necessary to relieve the medical symptoms presented.

3. A unit according to claim 1 which when inflated has sufficient volume to accommodate one person for transportation under pressure Figure 1.

4. A unit according to any preceeding claim which is portable and can be legally carried by one person Figure 1.

5. A unit according to any preceding claim whose body can be folded in any required manner or compressed into a small volume when not in use Figure 1.

6. A unit according to any preceeding claim which is of woven construction forming a tubular shape with rounded closed end Figure 2 in the one person version Figure 1 whose rounded closed end is formed by the continuous warp lengths Figure 3.22.

7. A unit according to any preceeding claim which relies both on stitching and friction to maintain its shape when pressurised Figure 1.

8. A unit according to any preceeding claim in which the outer layer of the body is woven by passing the warp lengths under and over the weft rings Figures 4.22 & 3.22.

9. A unit according to any preceeding claim whose outer layer of the body is wholly or partly of knitted construction Figure 4.22.

10. A unit according to any preceeding claim which may be woven or knitted or any combination of the two into a variety of shapes including sphericaL A 1. A unit according to any preceeding claim which is provided with a flexible collar round the opening which being completely flexible can be easily distorted to allow the larger unattached door to be passed through the opening and seated on the collar before gas is passed under pressure through a valve in the door to the inside of the vessel where gas pressurisation forces the door against the impermeable liner covering the collar to form a seal Figures 1.18 & 4.18.

12. A unit according to any preceeding claim which is woven or knitted from a single or combination of man made fibres for example polyester or aramide or polyethylene.

13. A unit according to any preceeding claim in which the outer layer of the body is assembled by weaving or knitting or double weaving or in combination or any other method involving the passing of thread or threads or yarn or other filaments over and under one another or through loops to form a webbing or knitted material which has a shape open at one or two positions or more such as a tube with one closed end or a tube with two ends open or a tube with multiple openings or any other shape enclosing a space which can be used as a pressure vessel or part of a pressure vessel.

14. A unit according to claim 13 in which the outer fabric material of the body figure 1 is made from woven strips to form the weft rings that are formed from strips of said flexible plastics material with the ends fastened together and spaced along the length of the body whilst the warp strips extend from the interior of the vessel over, the collar and down the length of the vessel then across the other end and up the length of the vessel over the collar and into the vessel as per Figures 1 & 2.12 & 3.22 and 4.22.

15. A unit according to any proceeding claims which may be laid flat and placed between two objects before inflating to a considerable pressure sufficient to lift a great weight figure 1.

16. A unit according to any preceding claim which has other medical and engineering applications.

17. A unit according to any preceeding claim which may be modified by the installation of tubes located inside or outside the body which when filled under pressure stiffen sufficiently to hold the vessel in its pressurised shape.

18. A unit according to any preceeding claim which may be used to relieve a variety of medical conditions which has an inner gas impermeable layer Figure 1.4 and an unattached'door both of which can be removed and replaced after each use Figure 1.18.

19. A unit according to any preceeding claim which may comprise a number of individual sub-units joined to one another each of which may have dfferent internal pressures or the same.

20. A unit according to any preceeding claim in which the door may be hinged on a rigid collar secured to the end of the vessel with an additional compressible seal provided between the rigid collar and the flexible collar of the body.

21. A unit according to any preceeding claim whose door is equipped with different inlet or outlet valves to allow the connection of difterent couplings sizes for different gas cylinders or other gas sources Figure 1. 18.

22. A unit according to any preceeding claim that can be pressurized up to 10 BAR or more Figure 1. A unit according to any preceeding claim that may be used for medical purposes other than those associated with diving Figures 1 & 4.

23. A unit according to any preceeding claim that may be used for medical purposes other than those associated with diving Figures 1 & 4.