WO2004082552A1

WO2004082552A1 - Pressure chamber

Info

Publication number: WO2004082552A1
Application number: PCT/GB2004/001139
Authority: WO
Inventors: Alexander Burnup
Original assignee: Alexander Burnup
Priority date: 2003-03-18
Filing date: 2004-03-17
Publication date: 2004-09-30
Also published as: GB0306164D0; GB2416365A; GB0520960D0; GB2416365B

Abstract

Portable flexible hyperbaric chamber (1) comprising a main body (2) with two outwardly projecting neck collars (14) and a closure (4) with two complementary inwardly projecting closure collars (24). Each collar (14,24) includes circumferentially disposed polyester fibre coils. A major portion of each of the main body (2) and the closure (4) is made from woven strips of material which material may also be of woven construction so that the whole chamber can be collapsed and folded for storage. A zip seal (62) with complementary parts connected to the main body (2) and the closure (4) hold the collars correctly juxtaposed relative to each other so that they sealingly engage each other in a form locking manner when the chamber (1) is pressurised.

Description

PRESSURE CHAMBER

The present invention relates to a flexible pressure chamber of the type suitable for use as a hyperbaric chamber for carrying out decompression treatment of a diver and which can be folded 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 or hyperbaric 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. In the past a number of flexible chambers have been proposed to facilitate transportation of the chambers. All of these chambers have however included a rigid access cover which means that they still weigh a significant amount and cannot be easily packed into a suitcase which would be useful for divers travelling abroad by aeroplane who wish to take their own hyperbaric chamber with them. An example of a prior art flexible hyperbaric chamber is described in United Kingdom Patent 2,356,211.

An object of the invention is to overcome the above- mentioned disadvantage.

Thus, according to the invention, there is provided a pressure chamber comprising a flexible main body with a neck including neck sealing means and a closure with closure sealing means, the closure being configured to be urgeable by pressure inside the chamber to urge the closure sealing means into sealing engagement with the neck sealing means in a form locking manner, wherein the closure comprises a flexible cover.

By making the cover flexible, as well as the main body, the entire pressure chamber can be designed so as to be folded and will accordingly fit into a smaller space than prior art flexible hyperbaric chambers.

In order to facilitate secure connection between the main body and the closure, preferably at least one and more preferably both, of the main body and the closure include at least one protruding collar. When both include such protruding collars, the closure can be engaged with the neck of the main body by inter-engagement of such collars .

So as to provide a particularly secure inter- engagement of the closure and neck of the main body, and to provide a particularly effective seal therebetween, preferably the neck sealing means includes two protruding collars and the closure sealing means also includes two protruding collars each of which is engageable with one of the neck sealing means collars.

Preferably the or each neck sealing means collar protrudes outwardly and the or each closure sealing means collar protrudes inwardly in order to facilitate the securing of the cover to the main body. Preferably the or each collar includes flexible circumferentially disposed tension members in order to resist high hoop stresses experienced by such a chamber.

The tension members may comprise one or more filaments or strands wound so as to form substantially superimposed coils. More preferably each collar contains a multiplicity of such superimposed coils.

Preferably the main body includes a major portion made of material which extends to the neck sealing means where it is looped around the at least one protruding collar. With such an arrangement, the major portion of the main body is securely connected to the at least one collar and, as the chamber becomes pressurised, the form locking interconnection of the closure with the main body will ensure that there is no possibility of the material of the major portion of the main body becoming separated from the at least one collar regardless of what stitching is employed to secure the material to the collars. For similar reasons, preferably the closure includes a closure body made of material which extends to the closure sealing means where it is looped around the at least one protruding collar.

In order to ensure an even more secure connection of the elements referred to above, preferably at least one of the neck sealing means and the closure sealing means includes circumferentially disposed weft material situated in the region of the at least one collar.

So as to facilitate holding the sealing means of the cover in close proximity to that of the main body, in order that internal pressurisation of the chamber effects a rapid sealing between the sealing means of the cover and the main body, the chamber preferably includes locating means for holding the closure sealing means and the neck sealing means in a particular juxtaposition relative to each other prior to pressurisation of the pressure chamber. The locating means can conveniently comprise a zip or hook and loop fabric joining means.

Preferably the cover includes warp material extending from the closure sealing means to an opposite end of the closure and weft material with which the warp material is woven. Provided the warp and weft are made from material with a suitable tensile strength, such a woven arrangement will provide excellent longitudinal (i.e. warp direction) tensile strength and excellent hoop (i.e. weft direction) tensile strength. The effect of internal pressure on the woven warp and weft is that increased structural integrity of the chamber results from friction between the warp and weft material .

In order to provide a strong end to the closure at the opposite end to that at which the sealing means is provided, preferably the cover includes continuous lengths of warp material which extend from the closure sealing means around an opposite end of the closure and back to the closure sealing means. Each end of each length of warp material is preferably connected to the or each closure collar as described above.

Preferably at least one of the main body and the closure includes a gas-proof layer positioned inwardly of material included to provide tensile resistance in order that there is no requirement for the warp and weft material to be connected together in a gas-tight manner. Conveniently the gas-proof layer comprises a lining member or an applied coating which may be sprayed on, painted on etc .

The pressure chamber is preferably adapted for accommodating one person only and is preferably portable.

The invention will now be described by way of example only with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a pressure chamber in accordance with the invention;

FIG. 2 is a partially cutaway view of the chamber shown in Fig. 1 with the lifting handles omitted; and

FIG. 3 is a partial cross-section on the line 3-3 of Fig. 2 showing the engagement between the main body and the closure.

The pressure chamber includes a main body 2 and a closure 4, each of which has external carrying handles 6.

The main body 2 has a major portion 8 and a neck 10 adjacent an open end 12. Two outwardly projecting neck collars 14 extend around the neck 10 and each comprises a multiplicity of polyester fibre coils 26. All polyester fibre in a single collar is conveniently formed from a single fibre wound into a composite coil and fixed in that configuration by a plurality of bindings 18 spaced around the circumference of the composite coil.

The closure 4 has a closed end 22 and an open end 20 adjacent to which and on an inner surface of which two inwardly projecting closure collars 24 are provided, each of which is made up from polyester fibres 26 and bindings 28 in the same way as the neck collars 14.

The majority of the closure 4 is made up from webs or strips made from woven polyester fibres including warp strips 32 and weft strips 30 which are woven with each other as shown in Fig. 3. At least some of the wefts may each be formed from a single strip which extends around the closure once with an appropriate amount of sewn overlap so that frictional forces, in addition to stitching (not shown) will resist hoop stress in the wefts .

As shown in Fig. 3 each warp strip 32 has a starting point 34 at an inner surface of the closure and positioned proximally of the closure collars 24. The warp strip 32 extends from the starting point 34 over both of the closure collars 24, outwardly round a distal one of the closure collars 24 where it doubles back on itself and extends directly in a substantially straight line between the two closure collars and is then woven in and out of the weft strips 30 towards the closed end 22 of the closure 4 where it extends around the closed end 22 and returns along the opposite side of the closure 4 where it is woven in and out of substantially diametrically opposite portions of the weft strips 30 back to substantially diametrically opposed portions of the closure collars 24 where it is wound round the closure collars in an arrangement which is a mirror image of that shown in Fig. 3. The end point of the weft is accordingly on the inside of the closure 4 proximally of the closure collars 2 . Where the warps 32 and 44 cross at the closed ends of the closure 4 and main body 2, they are all sewn together to provide the required strength.

Sewing or gluing between inner and outer layers of the warps occurs at least at the positions marked 36, 38 and 40 in order to ensure that the closure collars 24 project inwardly from an outer surface 50 of the closure 4 with a recessed weft portion 42 between the two closure collars. The warp strips 44 and weft strips 46 of the main body 2 are arranged in a like manner with respect to the neck collars 14 except that the neck collars 14 project outwardly from an inner surface 48 of the main body 2. This arrangement will accordingly not be described in detail .

The closure also includes an additional reinforcing weft ring 52 situated around the outside of the warp strips 32 sandwiching the closure collars 24. Similarly, the main body 2 includes a first reinforcing weft ring 54 which extends between the two neck collars 14 and a second reinforcing weft ring 56 which extends proximally of the proximal neck collar 14 inside the region occupied by the proximal closure collar 24. Both of these reinforcing weft rings 54, 56 are situated on the outside of the main body warps . To increase the strength of the reinforcing weft rings each will be made from a single strip of material with a considerable circumferential overlap. A double layer of the material may exist around the entire circumference of each such ring. The overlap region will be stitched securely. A cup-shaped main body gas-proof liner 58 lines the main body 2 and follows the route of the main body warps, i.e. doubled back and extending in a closely fitting arrangement over the neck collars. Similarly, a cup- shaped closure gas-proof liner 60 lines the closure and follows the route of the closure warps, i.e. in a closely fitting arrangement inside the closure collars 24 and doubling back along the outer surfaces of the closure collars 24.

A locating means in the form of a zip seal 62 is provided for holding the distal open end 20 of the closure and the neck 10 of the main body 2 in the correct juxtaposition relative to each other when pressurisation of the chamber 1 commences. A first side 68 of the zip is connected to the neck 10 of the main body 2 adjacent one of the neck collars 14 and a second side 70 of the zip is connected to the closure 4 adjacent its open end 20 and next to the closure collar 24 situated there.

A gas filling port 64 and a vent port 66 are provided in the closure. The following additional ports may be provided; one or two inlets for breathable gas such as air or oxygen; one or two breathable gas outlets one of which may be used as a body pressure vent; a spare port or vent; and a port for connection to a pressure line for connection to a control panel or gauge attached directly to the chamber.

In use, a patient in need of decompression treatment, or some other form of treatment necessitating being located in a pressurised environment, is positioned in the main body 2. This process may be assisted by the provision of a network of tubes (not shown) extending around the main body and arranged to draw the main body substantially into the configuration shown in Figs. 1 and

2 when the tube network is pressurised. The open end 20 of the closure 4 is then passed over the open end 12 of the main body 2 so that each closure collar is situated on the proximal side (with respect to the main body) of and closely adjacent to an associated one of the neck collars

14. The first and second sides 68 and 70 of the zip are zipped together and pressurised gas, such as air, is fed into the chamber through the filling port 6 . As the chamber becomes pressurised, each closure collar 24 is drawn sealingly against its associated neck collar 14 and in so doing presses adjacent portions of warp material against each other thereby ensuring, as a result of frictional forces therebetween, that the warps do not pull away from the collars.

Once pressurised, the chamber will be so rigid that it can be carried by means of the handles 6 in the manner of a stretcher.

When there is a requirement to remove the patient from the chamber, it is simply depressurised by releasing gas through the vent port 66 , unzipping the zip 62 and removing the closure 4 from the main body 2.

Variations of the invention will be apparent to those skilled in the art.

The closure and main body may each only include a single collar. The or each closure collar may be outwardly protruding and engage a complementary inwardly protruding neck collar. The warp and weft members may be replaced by some other structure, such as a continuous membrane which is adapted to resist tensile longitudinal and hoop stresses. If such a membrane is gas impermeable, then the requirement for a separate liner can be dispensed with. The bundles of polyester fibres in each collar could be replaced by some alternative tension resisting means such as a homogenous flexible band of some suitable material. A polyethylene fibre known as Dyneema (RTM) or some other man-made fibre could be used instead of polyester fibres or a mixture of fibres could be employed.

One of the ports 64 and 66 may have a tube connected thereto which substantially extends to an opposite end of the chamber in order that a purging or circulating flow of gas through the chamber can be established if necessary.

This tube will also act as miniature air lift by removing quantities of excess liquid such as urine from the patient at such time as the chamber is used for long decompressions. At such times, the rigid chamber is raised a little at the head end of the patient.

The closure 4 may be completely separable from the main body 2 or attached thereto.

Various other ports and/or mechanical and/or electrical outlets may be provided depending on what type of communication with the interior of the chamber is required. Such ports or outlets may be welded or mechanically sealed to the closure or the main body. Electrically operated valves may be provided which are connected to an automatic control device possibly including suitable software for controlling the environment within the chamber. Walls of the chamber may be translucent or lighting may be provided inside the chamber and a video and/or two- way voice communication system may also be included.

Such a chamber could alternatively be used as an underwater lifting bag or used in outer space for emergency movement of persons or material using manual or automatically directed gas vents or used for storage of a gas or liquid.

Although a substantially cylindrical embodiment has been described, the chamber may be any other suitable shape such as spherical, cuboidal or dumb-bell shaped. Furthermore, the chamber could incorporate an entrance lock and/or be configured to accommodate two or more people such as a doctor and patient or a doctor and several patients.

The chamber is preferably designed to withstand 5 Bar and more preferably to withstand 10 Bar.

The pressure chamber described can be flattened, folded and placed in a compact space such as a suitcase and can be manufactured with no parts made of metal (some small fittings such as the gas vents and other additional equipment may be of metal) . The chamber can be designed to easily pass through a standard air lock of a medical recompression chamber or that of a submarine. This provides the possibility of passing patients between submarines or decompressing the patients at different rates . The use of a flexible closure enables the weight of the chamber to be substantially reduced relative to a chamber with a rigid metal closure. The weight of the chamber described in United Kingdom patent 2,356,211 is typically around 30 kg. A chamber in accordance with the present invention can be manufactured to weigh as little as 20 kg .

Claims

1. Pressure chamber (1) comprising a flexible main body (2) with a neck (10) including neck sealing means (14) and a closure (4) with closure sealing means (24), the closure (4) being configured to be urgable by pressure inside the chamber (1) to urge the closure sealing means (24) into sealing engagement with the neck sealing means (14) in a form locking manner wherein the closure (4) comprises a flexible cover.

2. The pressure chamber (1) according to claim 1 wherein the neck sealing means includes at least one protruding collar (14) .

3. The pressure chamber (1) according to claim 1 or 2 wherein the closure sealing means includes at least one protruding collar (24) .

4. The pressure chamber (1) according to claim 2 or 3 wherein the neck sealing means includes two protruding collars (14) and the closure sealing means includes two protruding collars (24) each of which is engageable with one of the neck sealing collars (14) .

5. The pressure chamber (1) according to claim 2, 3 or 4 wherein the or each neck sealing means collar (14) protrudes outwardly and the or each closure sealing means collar (24) protrudes inwardly.

6. The pressure chamber (1) according to any one of claims 2 to 5 wherein the or each collar (14,24) includes one or more circumferentially disposed tension members

(26) .

7. The pressure chamber (1) according to claim 6 wherein the or each collar (14,24) includes at least one coiled circumferentially disposed filamentary tension member

(26) .

8. The pressure chamber (1) according to claim 2 or any claim depending thereon wherein the main body (2) includes a major portion (8) made of material (44) which extends to the neck sealing means where it is looped around the at least one protruding collar (14) .

9. The pressure chamber (1) according to claim 3 or any claim depending thereon wherein the closure (4) includes a closure body made of material (32) which extends to the closure sealing means where it is lopped around the at least one protruding collar (24) .

10. The pressure chamber (1) according to any one of claims 2 to 9 wherein at least one of the neck sealing means (14) and the closure sealing means (24) includes circumferentially disposed weft material (52,54,56) situated in the region of the at least one collar (14,24) .

11. The pressure cha ber (1) according to any preceding claim including locating means (62,68,70) for holding the closure sealing means (24) and the neck sealing means (14) in a particular juxtaposition relative to each other prior to pressurisation of the pressure chamber (1) .

12. The pressure chamber (1) according to claim 11 wherein the locating means (62,68,70) comprises a zip.

13. The pressure chamber (1) according to claim 11 wherein the locating means comprises hook and loop fabric joining means .

14. The pressure chamber (1) according to any preceding claim wherein the closure (4) includes warp material (32) extending from the closure sealing means (24) to an opposite end (22) of the closure (4) and weft material

(30) with which the warp material (32) is woven.

15. The pressure chamber (1) according to any preceding claim wherein the closure (4) includes continuous lengths of warp material (32) which extend from the closure sealing means (24) around an opposite end (22) of the closure (4) and back to the closure sealing means (24) .

16. The pressure chamber (1) according to any preceding claim wherein at least one of the main body (2) and the closure (4) includes a gas proof layer (58,60) positioned inwardly of material (30,32,44,46) included to provide tensile resistance.

17. The pressure chamber (1) according to claim 16 wherein the gas proof layer (58,60) comprises a lining member or an applied coating.

18. The pressure chamber (1) according to any preceding claim wherein the closure (4) , including the closure sealing means (24), is foldable.

19. The pressure chamber (1) according to any preceding claim wherein the closure (4) includes a closure body made of woven material (30,32) .