This invention relates to inflatable containers and valves for use therein and more particularly, but not exclusively, to containers having a valve formed integrally therewith.

Inflatable containers of the type used, for example, as flotation bags are commonly made from flexible sheet material within which is incorporated a valve to allow the container to be inflated and deflated when appropriate. However existing valves for such containers are generally made of metal or plastic components which stand proud of the surface of the container; they are therefore susceptible to damage and, especially when being stored in stacks in the deflated state, can readily cause damage to adjacent containers in the stacks through penetration of the wall of those containers. Such problems can be exacerbated when the containers are being stored in bulk in confined spaces, for example on a ship when it may be unavoidable for crew members to walk over the stacks of containers.

Disclosure of the Invention There is therefore| need for a container having a

I r valve which, is not.susceptible to damage (or ^* causing damage) in these ways. The present invention generally provides such a valve which may be used separately or integrally with an inflatable container of the type described above.

∑π. accordance with the invention, there is provided an inflatable container having a valve comprising a flexible diaphragm which is attached to an inside surface of the container about an aperture in the surface so as to cover the aperture and define a sealing area with the inside surface around the periphery of the aperture between the aperture and peripheral openings into the container so that in use the container is inflated by fluid flowing throug -the aperture, between the container and the diaphragm and through the openings, but deflation is resisted by internal fluid pressure causing the diaphragm to contact the surface at the sealing area, characterised in that said openings are located around the aperture so that depression of the diaphragm by pressing on it centrally through the

aperture will break the sealing contact between the diaphragm and sealing area to expose said openings.

In one example, the container is made from a flexible material; for use at sea, in particular, a rubber coated Nylon or similar material can be employed to good effect. In one of its least complex forms, the container may comprise a simple "pillow" or "barrel" shape.

The aperture, preferably circular, is formed at a chosen position for the valve on the surface of the container. Strengthening of the container surface in the vicinity of the aperture may be effected if necessary, for example, by securing a reinforcing ring about the aperture on an outside surface of the container.

The diaphragm must be flexible and of a shape and size sufficient to completely cover the aperture to form the sealing area with the container around the aperture and to be secured to the container away from the sealing area.

Advantageously, especially in the case of a circular aperture, the diaphragm comprises a circular disc having a di'ameter larger than that of the aperture, with said openings formed around the periphery of the disc, preferably on a circle concentric with, and having a radius about twice that of, the aperture.

The diaphragm must be positioned inside the container and secured thereto in a manner which allows fluid to be forced under pressure between the container and the diaphragm and through said openings to the inside of the container, but which does not interfere with the sealing area between the diaphragm and the container.

The diaphragm may be secured to the inside of the ^" container by bonding the outer edge-to the container leaving said openings clear for fluid flow. The whole of the outer edge may be bonded with the openings formed away from the edge, or the openings may be formed as cut-outs in the outer edge with the portions therebetween being bonded. Alternatively, the diaphragm may be secured to the inside of the container by means of

ties around the outer edge of the diaphragm with said openings therebetween and/or with the ties passing through said openings.

The characteristics of the container material and diaphragm material must be such that they are capable of forming a good seal at the sealing area when the latter is forced against the former by fluid pressure in the container. These characteristics can either be inherent in the respective materials or the materials may be treated in the relevant areas to enable the seal to be formed.

In preferred embodiments of the invention, the diaphragm material has a greater elasticity than the container material so that, in use, the diaphragm is partially forced through the aperture and thereby cause a better seal to be formed at the edge of the aperture in particular. A diaphragm of silicone rubber (advantageously reinforced) is especially preferred.

Furthermore, it is- advantageous for the inside surface of the container about the aperture to

have formed therein an internally protruding lip against which the diaphragm can seal.

Most preferably, all the components of the container and the valve are wholly or partially composed of rubber or similar substances such that they may all be assembled together and then bonded in. a predetermined manner by a simple pressure/heat treatment.

For example, all the container/valve components may usefully be made of rubber, preferably neoprene rubber, in an uncured state except for the diaphragm which, as stated above, is preferably of silicone rubber. A single treatment

O V of the components at, say, 150 C at 60 psi can therefore be used to bond the components together - - ^{" ~} - ^{" "} except for the silicone rubber diaphragm which will not bond under such conditions. Such bonding can include the container edges in addition to the valve area of the container although clearly a separation sheet or sheets will be required to prevent the container sides being bonded together.

In all embodiments of the invention, the size and

shape of the aperture and of the diaphragm and the mode of securing the diaphragm to the container may be varied according to the intended use of the container.

Deflation of the container will normally be effected by depressing the diaphragm relative to the container surface, and the number and size of said openings may be varied to take account of desired inflation/deflation rates.

Description of the Drawings

Reference will now be made for the purpose of exemplification only to the accompanying drawings in which:

Figure l is a top view of a container of the invention,

Figure 2 is a side view of the container of Figure 1,

Figure 3 is an enlarged sectional view along the line III - III of Figure 1,

Figure 4 is a view of the diaphragm only of the containers of Figures 1 to 3, and

Figure 5 is a view of a modified diaphragm for a container of the invention.

Best Method of Carrying Out the Invention With reference to the drawings, Figures 1 and 2 show diagrammatically a cushion-shaped container 1 of the invention made from reinforced neoprene and having a valve 2 positioned in one wall of the container.

The valve 2 comprises - see Figure 3 - a diaphragm

3 of reinforced silicone rubber positioned on the inside surface of the container 1 about a circular aperture 4 in the container surface. The aperture

4 is strengthened by the presence of a disc 5 on the outer surface of the container 1 which is made from reinforced neoprene.

The diaphragm 3 is secured to the inside surface of the container by means of a plurality of ties 6 - see also Figure 4 - whic pass through holes 7 in the diaphragm and whose ends are fixed to the

inside surface.

The inside surface of the container adjacent the aperture 4 has bonded thereto a ring 8 of non-reinforced neoprene rubber chosen so that it can form a good seal with the adjacent surface of the diaphragm and positioned to form a lip against which the seal is formed and enhanced.

Prior to manufacture, the container and valve components were all uncured with the exception of the diaphragm which was pre-cured. With a dividing sheet of paper in place, therefore, the container/valve was made by assembling the components in the manner shown in Figure 3 and o -•' ^■ heating these together at 150 C at 60 psi.

In the assembled form, the diaphragm and the inside surface of the container 1 define a sealing area inwardly of the ties 6 and especially between the diaphragm and the ring 8.

Pressurised fluid, normally air, can be injected between the diaphragm 3 and ring 8 and between the ties 6 and through openings 7 into the interior of

the container by any standard means, for example a compressed air nozzle. Internal container pressure, however, causes the membrane to seal against the inner surface of the container and against the ring 8 in particular and thereby resist deflation.

The relative greater elasticity of the diaphragm material causes the internal container pressure to force the ^" diaphragm 3 partially through the aperture in the container and thereby be somewhat proud of the container surface.

Depression of the diaphragm 3 towards the interior of" the container causes loss of sealing between the diaphragm and the container and exposes the openings 7 to allow deflation of the container.

The alternative form of diaphragm shown in Figure 5 can be bonded to the inside surface of the container and across the annular band 9 (the limit of bonding being indicated by broken line 12) but a plurality of holes 10 in the diaphragm between this band and the sealing area adjacent the container aperture 11 allows air to penetrate the

interior of the container during inflation and be expelled therefrom during deflation. Preferably, the holes 10, like the holes 7 in Figure 4, lie on a circle concentric with the aperture 11 and having a radius about twice that of the aperture

11.