GB2048062A

GB2048062A - Operating Head for Fire Extinguisher

Info

Publication number: GB2048062A
Application number: GB7909518A
Authority: GB
Original assignee: RAMPART ENG CO Ltd
Current assignee: RAMPART ENG CO Ltd
Priority date: 1979-03-19
Filing date: 1979-03-19
Publication date: 1980-12-10
Also published as: GB2048062B

Abstract

A fire extinguisher cylinder 10 has a neck ring 12 formed with an axially directed outlet hole or pipe 14 for pressurised fire fighting medium. The outlet hole is sealed by means of a thin metal disc 16. A firing head 19 has an axially slidable piston 26 which actuates a piercing member 21 and is held in its rest position by means of a locking pin, which fits into bores 30 of the firing head. When the pin is removed, a coil spring 27 forces the piston 26 downwardly so that the piercing member 21 penetrates through the disc 16 to permit the fire fighting medium to escape through flow space 20 and passage 35. The firing head is of simple construction and easy to operate and is suitable for operation manually by removal of the pin or remotely by means of a cartridge actuator 37 and associated firing pin. <IMAGE>

Description

SPECIFICATION Operating Head for Fire Extinguisher The present invention relates to a fire extinguisher which is a cylinder containing a pressurised fire fighting medium and which is provided with a novel construction of operating head.

Such extinguishers may incorporate a head formed with an axial outlet hole closed off by means of a thin copper disc. The outlet side of the disc is provided with a hollow axially movable plunger which may be depressed by actuation of an operating handle to pierce the disc and allow escape of the pressurised fire fighting medium. In an alternative design of fire extinguisher the outlet hole is closed off by means of a thin metal cap, and a remotely operated cartridge actuator has a firing pin which is arranged to penetrate and destroy the cap there by allowing escape of the fire fighting medium.The lever operated fire extinguishers incorporate a locking pin which has to be removed before the operating handle can be actuated, but they are complicated and expensive to construct and two operations are necessary, that is to say removal of the locking pin followed by actuation of the operating handle. The automatically operated fire extinguishers may have a remote firing control, which can be operated manually, but there is no provision for manual actuation of the cylinder itself without recourse to an associated electrical firing system.

The present invention provides a fire extinguisher comprising in combination: a cylinder containing a pressurised fire-fighting medium and having a neck formed with an outlet hole closed off by a sealing disc; an axially movable piercing member; a piston disc slideable in a bore in a housing secured in the extinguisher neck in axial alignment with the sealing disc and biassed towards the sealing disc, the piston disc and the sealing member interengaging so that movement of the piston disc towards the sealing disc effects corresponding movement of the piercing member; and a removable locking pin inserted through transverse bores in the housing into engagement with the lower face of the piston disc to hold it in a retracted inoperative position.

It will be appreciated that removal of the locking pin causes the piston disc, and therefore the piercing member, to move rapidly towards the sealing disc which becomes pierced to allow escape of the fire fighting medium from the cylinder to the location where it is required.

Passages may be formed in the housing to direct the flow of fire fighting medium appropriately, and the housing may be provided with a threaded bore for interconnection of a pipe through which the fire fighting medium can flow.

In a preferred construction the free end of the piercing member is in contact with an axially movable firing pin of a cartridge actuator whereby the fire extinguisher may be operated by remote electrical firing as well as direct manual firing by removal of the locking pin.

An embodiment of the invention will now be described by way of example only, with reference to the accompanying drawing in which: Figure 1 is a view in transverse section of the neck portion of a fire extinguisher cylinder together with its associated operating head; and Figure 2 is a plan view of a locking pin for insertion into the head of the cylinder shown in Figure 1 to hold the piston disc in the inoperative position.

A cylinder 10 of drawn steel or aliminium contains a pressurised fire fighting medium such as carbon dioxide or bromochlorodifluoromethane and has a female threaded neck 11. A neck ring 12 is screwed into the neck 11 and has an axially directed outlet hole at its lower end communicating with the pressurised fire fighting medium in the cylinder optionally via a pipe 14 which extends downwardly into the body of the cylinder. The upper end of the outlet hole 13 communicates with a larger intermediate bore 1 5 which is internally threaded. A sealing disc 1 6 of thin metal sheet such as copper or nickel sheet fits flat against the lower end of the bore 1 5 and is urged into sealing engagement with the top end of the outlet hole by means of a male threaded clamping ring 17.The upper end of the neck ring 12 is formed with a relatively large bore 18 which is also female threaded and communicates with the top end of the intermediate bore 1 5. A firing head 19 has a male threaded lower end which screws into the upper bore 1 8 so that when it is fully tightened its lower end is clear of the lower end of the upper bore 18 so as to define a generally cylindrical gas flow space 20. The head 19 is formed with an axial bore within which slides a piercing member 21 having a pointed head 22 at its lower end for piercing the sealing disc 1 6. The firing head 1 9 is sealed at its lower end to the piercing member 21 by means of an 0ring seal 23 retained in position by means of a retaining ring 24.The upper end of the piercing member 21 extends into a relatively large axial cylinder 25 formed in the top end of the head 19.

A firing piston 26 is slidable axially ithin the cylinder 25 and is urged downwardly towards the sealing disc 1 6 by means of a coil spring 27 which in an inoperative position shown in the right hand side of Figure 1 is held in compression between the top face of the firing piston 26 and a seat on a spring clamping sleeve 28 which is retained by means of a threaded end cap 29 which is screwed to the top end of the firing head 1 9. The head 1 9 is formed with transverse bores 30 which open into the cylinder 25 at an appropriate level. Two such bores 30 are formed, symmetrically to either side of the piercing member 21.A removable locking pin 31 has parallel limbs 32 and 33 which fit into the transverse bores 30 and, when the spring 27 is compressed, provide a location for the firing piston 26 to hold it in a retracted position. The piercing member 21 is provided, on the side of the firing piston 26 nearer to the sealing disc 1 6, with a circlip 34. Therefore, when the locking pin 31 is removed, the axial load of the spring 27 on the firing piston 26 is transmitted via the circlip 30 to the piercing member 21 which is forced fighting medium to escape from the cylinder into the gas flow space 20.The firing head 1 9 is formed with generally axial gas outlet passage 35 communicating with the gas flow space 20 and terminating at its upper end in an outlet port 36 from which the firing extinguishing medium can either be sprayed directly onto the fire or can be supplied to a gas transport pipe.

Within the locating sleeve 28 is provided a cartridge actuator 37 which may be operated electrically to urge a firing pin (not shown) at its lower end against the top end of the piercing member 21 to force the piercing member downwardly through the sealing disc 1 6. The cartridge actuator 37 may be fired in response to a remote sensing device, or to a remotely operated push button forming part of an electrical control circuit.

It will be appreciated that various modifications may be made to the embodiment described herein without departing from the invention, the scope of which is set out in the appended claims.

Claims

Claims

1. A fire extinguisher comprising in combination: a cylinder containing a pressurised fire fighting medium and having a neck formed with an outlet hole closed off by means of a sealing disc; an axially movable piston member; a piston disc slidable in a bore in a housing secured in the extinguisher neck in axial alignment with the sealing disc and biassed towards the sealing disc, the piston disc and the sealing member interengaging so that movement of the piston disc towards the sealing disc effects corresponding movement of the piercing member; and a removable locking pin inserted through transverse bores in the housing into engagement with the lower face of the piston disc to hold it in a retracted inoperative position.

2. A fire extinguisher according to Claim 1, wherein the piston disc is biassed towards the sealing disc by means of a coil spring held in compression when in the retracted inoperative position.

3. A fire extinguisher as claimed in Claim 1 or 2, wherein the lower face of the piston disc locates against a circlip on the piercing member to enable the piston disc to effect firing movement of the piercing member.

4. A fire extinguisher as claimed in any preceding claim wherein the removable locking pin has parallel limbs which fit into transverse bores disposed symmetrically to either side of the piercing member.

5. A fire extinguisher as claimed in any preceding claim, further comprising a cartridge actuator whose firing pin is in axial alignment with the top end of the piercing member.

6. A fire extinguisher having a head arranged for firing by means of a removable locking pin, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

New Claims or Amendments to Claims filed on 25/7/80.

Superseded Claims 1.

New or Amended Claims:

1. A fire extinguisher comprising in combination: a cylinder containing a pressurised fire fighting medium and having a neck formed with an outlet hole closed off by means of a sealing disc; an axially movable piston member; a piston disc slidable in a bore in a housing secured in the extinguisher neck in axial alignment with the sealing disc and biassed towards the sealing disc, the piston disc and the piercing member being arranged so that movement of the piston disc towards the sealing disc effects corresponding movement of the piercing member; and a removable locking pin inserted through transverse bores in the housing into engagement with the lower face of the piston disc to hold it in a retracted inoperative position.