GB1582079A

GB1582079A - Fluid storage vessels

Info

Publication number: GB1582079A
Application number: GB46488/77A
Authority: GB
Original assignee: BOC Ltd
Current assignee: BOC Ltd
Priority date: 1977-11-08
Filing date: 1977-11-08
Publication date: 1980-12-31
Also published as: FR2408091A1; BE871806A; IT7829501A0; IT1100936B; FR2408091B3; IE782202L; IE47751B1

Description

(54) FLUID STORAGE VESSELS (71) We, BOC LIMITED, of Hammerssmith House, London, W6 9DX, England, an English company, 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 statement : This invention relates to fluid storage vessel and particularly, though not exclusively, to vessels for storing gas or liquefied gas under pressure.

The invention is especially concerned with gas capsules of relatively small volume (e.g.

10-50 cc) such as, for example, those marketed by the present applicants under the registered trademark SPARKLETS. Such capsules are typically closed by a seal crimped or welded in an opening of the capsule and which, in use of the capsule, is punctured by a hollow piercing pin provided on the apparatus to which the stored gas is to be supplied or on an adaptor which can mate with such apparatus.

For various reasons, including its ease of assembly and greater reliability, a welded closure is to be preferred to a crimped closure. However, in as much as a puncturable seal type of closure cn only be applied to a capsule after it has been filled, welding techniques cannot safely be used to secure such closures to capsules containing oxygen, nitrous oxide or other inflammable gases.

Another problem with this type of closure, whether welded or crimped, is that once the seal has been punctured the capsule cannot be withdrawn from the utilisation apparatus or adaptor and still retain any unconsumed gas, and furthermore an empty capsule cannot be refilled and reused unless, of course, the remains of the seal are removed and a fresh seal atached.

The present invention seeks to overcome the above indicated drawbacks of conventional gas capsules and accordingly resides in a fluid storage vessel having an opening within which is secured a closure comprising a valve seat and a valve member, the valve seat being deformed by a metal member welded within said opening, the valve member being adapted to be urged into sealing contact with the valve seat by pressurised fluid when stored within the vessel but having a portion accessible from without the vessel by which the valve member can be moved out of contact with the seat to thereby provide fluid communication between the interior and exterior of the vessel.

In this way the vessel can be filled after welding the closure in place simply by unseating the valve member to provide access to the interior of the vessel, and in like manner the vessel can be refilled when empty as many times as may be desired. In use of the vessel its contents are also, of course, made available by suitably unseating the valve member and such a vessel has the advantage over a vessel having a puncturable seal type of closure that at any time the valve member can be allowed to reseat under the influence of the vessel pressure to thereby retain any unconsumed fluid during subsequent handling.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawing which is a sectional view of the neck and closure of a preferred embodiment of the invention.

The illustrated embodiment is a gas capsule the main body 1 of which may be the same as that conventionally employed in one of the types of capsule closed by a puncturable diaphragm marketed by the present applicants under the registered trademark SPARKLETS.

In this case, however, the capsule has a closure comprising a cup shaped member 2 having a central bore 2A surrounded by an annular valve seat 2B, and a valve member 3.

Member 2 also has an out-turned annular flange 2C which, during manufacture of the capsule, is welded by any suitable process to the annular end face 1A of the body 1.

Valve member 3 is made in three parts: a rivet 4, an elastomeric sealing washer 5 and a collar 6. The washer 5 is retained between the head of rivet 4 and the collar 6, and is so disposed as to be urged into sealing contact with the valve seat 2B when the capsule is pressurised. In addition, a coil spring 7 is provided to reseat the washer 5 when the capsule is empty. However, the shank of rivet 4 and the surrounding collar 6 collectively define a valve stem extending through the bore 2A by which the washer 5 can be mechanically unseated from without the capsule. collar 6 has a head of a larger diameter than that of bore 2A which accordingly limits the axial movement of the valve member when unseated.

It will be apparent that when it is desired to provide fluid communication between the interior and exterior of the capsule, i.e. when the capsule is to be filled or its contents dispensed, a suitable effort is applied to the valve stem to move washer 5 out of contact with the seat 2A so that gas can flow through the clearance space between the stem and the bore 2B, and that whenever the effort on the valve stem is relaxed the washer will immediately reseat to prevent the escape of such gas as remains within the capsule at that time.

It will also be observed that the end surface 8 of the valve stem is generally flush with the top of the capsule when washer 5 is seated, or in other words it occupies the same position as does the puncturable seal on a conventionally closed capsule of equivalent type. In this way the illustrated capsule can be used in conjunction with any apparatus or adaptor designed to accept the conventional capsule, the piercing pin in this case serving not to puncture a seal but to unseat the valve member 3.

A further feature of the illustrated embodiment is the provision of an annular groove 2D coined or otherwise formed in the member 2 whereby that member can act as a burster disc in the event of the capsule becoming over pressurised. Preferably the groove 2D is interrupted at one circumferential point so that in the event of rupture the central portion of member 2 does not become completely detached and the ejection of the whole valve assembly is prevented.

It is envisaged that a capsule with a closure of the type illustrated may form the basis of a regulated gas dispenser, the valve member 3 being controlled by a spring and diaphragm assembly in a similar manner to the high pressure valve in a conventional pressure regulator. Similarly the capsule may form the basis of a constant dose dispenser.

WHAT WE CLAIM IS: 1. A fluid storage vessel having an opening in which is secured a closure comprising a valve seat and a valve member, the valve seat being defined by a metal welded within said opening, the valve member being adapted to be urged into sealing contact with the valve seat by pressurised fluid when stored within the vessel but having a portion accessible from without the vessel by which the valve member can be moved out of contact with the seat to thereby provide fluid communication between the interior and exterior of the vessel.

2. A vessel according to claim 1 wherein said metal member is cup shaped and has a bore therein to provide fluid communication between the interior and exterior of the vessel, the portion of said cup shaped member surrounding the bore on the side interior of the vessel defining said valve seat, and the valve member comprising a sealing head for cooperation with said seat and a stem extending from said head through said bore with clearance.

3. A vessel according to claim 2 wherein said stem carries, at its end remote from said sealing head, a second head of a diameter greater than that of said bore, thereby to prevent separation of the valve member from said cup shaped member.

4. A vessel according to any preceding claim wherein said metal member is configured to rupture before any other part of the vessel in the event of the vessel becoming over pressurised.

5. A vessel according to any preceding claim wherein, when the valve member is seated, said portion of the valve member accessible from without the vessel terminates substantially in the plane of said opening in the vessel.

6. A vessel according to any preceding claim further comprising spring means for biassing the valve member into sealing contact with the valve seat.

7. A fluid storage vessel substantially as hereinbefore described with reference to the accompanying drawing.

8. A vessel according to any preceding claim, being a capsule charged with gas or liquefied gas under pressure.

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

Claims

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

4 and the surrounding collar 6 collectively define a valve stem extending through the bore 2A by which the washer 5 can be mechanically unseated from without the capsule. collar 6 has a head of a larger diameter than that of bore 2A which accordingly limits the axial movement of the valve member when unseated.

It will be apparent that when it is desired to provide fluid communication between the interior and exterior of the capsule, i.e. when the capsule is to be filled or its contents dispensed, a suitable effort is applied to the valve stem to move washer 5 out of contact with the seat 2A so that gas can flow through the clearance space between the stem and the bore 2B, and that whenever the effort on the valve stem is relaxed the washer will immediately reseat to prevent the escape of such gas as remains within the capsule at that time.

It will also be observed that the end surface 8 of the valve stem is generally flush with the top of the capsule when washer 5 is seated, or in other words it occupies the same position as does the puncturable seal on a conventionally closed capsule of equivalent type. In this way the illustrated capsule can be used in conjunction with any apparatus or adaptor designed to accept the conventional capsule, the piercing pin in this case serving not to puncture a seal but to unseat the valve member 3.

A further feature of the illustrated embodiment is the provision of an annular groove 2D coined or otherwise formed in the member 2 whereby that member can act as a burster disc in the event of the capsule becoming over pressurised. Preferably the groove 2D is interrupted at one circumferential point so that in the event of rupture the central portion of member 2 does not become completely detached and the ejection of the whole valve assembly is prevented.

It is envisaged that a capsule with a closure of the type illustrated may form the basis of a regulated gas dispenser, the valve member 3 being controlled by a spring and diaphragm assembly in a similar manner to the high pressure valve in a conventional pressure regulator. Similarly the capsule may form the basis of a constant dose dispenser.

WHAT WE CLAIM IS: 1. A fluid storage vessel having an opening in which is secured a closure comprising a valve seat and a valve member, the valve seat being defined by a metal welded within said opening, the valve member being adapted to be urged into sealing contact with the valve seat by pressurised fluid when stored within the vessel but having a portion accessible from without the vessel by which the valve member can be moved out of contact with the seat to thereby provide fluid communication between the interior and exterior of the vessel.
2. A vessel according to claim 1 wherein said metal member is cup shaped and has a bore therein to provide fluid communication between the interior and exterior of the vessel, the portion of said cup shaped member surrounding the bore on the side interior of the vessel defining said valve seat, and the valve member comprising a sealing head for cooperation with said seat and a stem extending from said head through said bore with clearance.
3. A vessel according to claim 2 wherein said stem carries, at its end remote from said sealing head, a second head of a diameter greater than that of said bore, thereby to prevent separation of the valve member from said cup shaped member.
4. A vessel according to any preceding claim wherein said metal member is configured to rupture before any other part of the vessel in the event of the vessel becoming over pressurised.
5. A vessel according to any preceding claim wherein, when the valve member is seated, said portion of the valve member accessible from without the vessel terminates substantially in the plane of said opening in the vessel.
6. A vessel according to any preceding claim further comprising spring means for biassing the valve member into sealing contact with the valve seat.
7. A fluid storage vessel substantially as hereinbefore described with reference to the accompanying drawing.
8. A vessel according to any preceding claim, being a capsule charged with gas or liquefied gas under pressure.