AU600171B2

AU600171B2 - Automatic fire extinguisher head assembly valve

Info

Publication number: AU600171B2
Application number: AU22846/88A
Authority: AU
Inventors: Philip Patrick Thurn
Original assignee: WESTFIRE Pty Ltd
Current assignee: THURN PROPERTIES Pty Ltd
Priority date: 1987-10-01
Filing date: 1988-09-26
Publication date: 1990-08-02
Anticipated expiration: 2008-09-26
Also published as: AU2284688A

Description

71 COMMO N W E A LTH O F A US T RA LIA PATENT ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE CLASS INT. CLASS Application Number: Lodged: 0 Complete Specification Lodged: 6 0 Accepted: Published: 000 0 0.

0 0 Priority: a Related Prt-: 0 00 AEO PLCN:WSFR T.LD 00 NAME(S OF PICAENT:RS PEHIP PTIC LTD.

ADDRESS O APPLICN: UnitE 3& 74N Newands Rtoresevi including3073 tebsmehdoprfming t Stawntof itra AUTOMATIC FIRE EXTINGUISHER HEAD ASSEMBLY VALVE Q0 0 This invention relates to an extinguisher &oo head assembly.

0 More particularly, the invention relates to O an extinguisher head assembly which can be used on a pressure vessel which contains an extinguishant under pressure.

o COf °o 9 The general object of the invention is to provide a simple but effective assembly of this type.

According to the present invention there is provided an extinguisher head assembly comprising a I body having first and second bores, the first bore being of a smaller diameter than the second, the first bore being in use coupled to a source of extinguishant under pressure, said second bore forming part of a normally closed chamber, piston means having first and second portions slidably mounted in said first and second bores respectively, release means for releasing pressure in the chamber, said piston means including a pressure equalization opening therethrough to equalize pressure, in use, in the first and second bores, said body including an i: 2 outlet port which is closed by the piston means until the release means is operated to release pressure in the chamber whereby the piston means moves under the influence of the pressure of the extinguishant in the first bore to thereby open the outlet port and permit the extinguishant to pass through the outlet port.

The invention will now be further described with reference to the accompanying drawings, in which: Figure 1 is a side view partly in section of o a head assembly of the invention, o0 0 Figure 2 is a plan view of the assembly, al o Figure 3 is a side view partly in section of 9 0 othe body, Figure 4 is a cross-section along the line o oo 4-4, 00 0 oo 0Figure 5 is a side view partly in section of o o the cap, 0ooo Figure 6 is a plan view of the cap, 6 Figure 7 is another side view partly in section of the cap, and 0. Figure 8 is a side view of the plunger.

oo a 00 0 The extinguisher head assembly 2 of the invention includes a body 4, cap 6 and piston 8. The lower end of the body 4 includes a threaded spigot for mounting in the neck of a pressure vessel 12 which contains an extinguishant under pressure. A syphon tube 14, shown in broken lines, is fitted to the spigot 10 in order to extract the extinguishant from the pressure vessel 12, in the usual way.

3 The body 4 includes a shoulder 16 which is recessed to receive an O-ring 18 which seals against the top face of the neck of the pressure vessel 12.

As best seen in Figures 3 and 4, the body 4 includes first and second bores 20 and 22, the first bore being of narrower diamater than the second bore.

The second bore 22 extends through an externally threaded spigot 24 upon which is mounted the cap 6 0which has a complementary recess. The body 4 includes a discharge port 26 which extends transversely a a through the body and communicates with the second SC IObore 22. The port 26 is internally threaded so as to 0 00 receive a discharge tube (not shown) which is used to o 4 convey the extinguishant to the site where it is to be used.

00° The body 4 includer three recesses 28, 0 00 oo and 32 which extend radially inwardly and communicate awith the bore 20, as seen in Figure 4. The opening 28 i in use receives a filling valve (not shown) which enables the assembly to be coupled to a source of extinguishant under pressure for filling the pressure vessel 12. The opening 30 serves as a mounting point 2 for a pressure gauge 35, as seen in Figure 1. The opening 32 has mounted therein a bursting disc 36 which is arranged to rupture when the pressure in the bore 20 exceeds a predetermined level. In other words, the disc 36 functions as a pressure relief valve.

The cap 6 is illustrated in more detail in Figures 5, 6 and 7. It has an internally threaded recess 28 which receives the threaded spigot 24 of the body. The lower end of the recess includes a shoulder 30 upon which is seated an O-ring 32 which bears against a shoulder 34 formed on the body 4 adjacent to the spigot 24. The O-ring 32 forms a seal between the body 4 and the cap 6, as best seen in Figure i. The cap includes an opening 38 extending inwardly from the top of the cap, as shown in Figure ooo A connecting duct 40 extends from the "i opening 38 to the recess 28 but fluid communication o1 obetween these parts is prevented by means of a bursting disc 42 which is held seated in the opening 38 by means of an operating member (not shown). The o0 operating member preferably includes a threaded spigot which co-operates with internal threads of the 09 opening 38. The arrangement is such that the operating member ruptures the disc 42 so as to 90 0 99 relieve pressure within the recess 28 for the purpose to be explained hereinafter.

004 The cap 6 also includes a transversely extending opening 44 communicating duct 46 and 1 bursting disc 48 which function analogously to those i described above.

The piston 8 is illustrated in more detail in Figure 8. It has first and second portions 50 and 52 which are respectively slidable in the bores and 22 of the body 4. The portions 50 and 52 are provided with pairs of recesses 54 for receipt of O-rings 55 to sealingly engage the bores 20 and 22.

The piston 8 includes a central recess 56 which is open at the free end of the portion 50 but closed at L 77 the free end of the second portion 52 except for a pressure equalisation duct 58 which is of relatively narrow diameter. The duct 58 is surrounded by an annular recess 60 which in use receives an O-ring 62.

The operation of the assembly is as follows.

The assembly is mounted on the neck of the pressure cylinder 12 and extinguishant under pressure is admitted to the assembly via the opening 28. The piston 8 will be held in the position as shown in Figure 1 because the pressure in the first and second o bores 20 and 22 is equal because of the fluid a communication afforded by the equalisation duct 58.

The relatively small area of the first portion 50 of the piston relative to the second portion 52 ensures that the piston 8 will be held in this position. The o first portion 50 closes the discharge port 26 and the O-rings 55 prevent escape of gases. It will be 0 appreciated that the assembly will remain in this position until pressure in the bore 22 (or recess 28 0 of the cap 6) is released. The discharge port 20 can therefore be opended by rupturing one of the bursting Sdiscs 42 or 48 in the cap 6. This releases the a 0.pressure in the bore 22 (normally to atmospheric) whereupon the piston 8 will move upwardly under the influence of the pressure of the extinguishant in the pressure vessel. The extinguishant can then pass through the bore 20 and be discharged from the discharge port 26.

When the piston 8 moves upwardly, the O-ring 62 bears against the inner face 64 of the cap 6 so as to form a seal therewith. The diameter of the O-ring 62 is less than the diameter of the lower portion

L.

6 of the piston and thus the piston 8 will be held in its open position for substantially complete discharge of the contents of the pressure vessel.

When it is desired to refill the vessel, the cap 6 is removed and any bursting discs which have been ruptured are replaced (where discs have been used). The piston 8 is pushed downwards to its closed position in readiness for receiving a fresh charge of extinguishant through the opening 28.

0 00 a The actuators for releasing the pressure of O the top of the piston can be in the form of solanoid 000 valves, poppet valves or small ball valves. When used 0 \in the bursting disc form pnuematically or manually fired hollow pins are used.

00 The assembly of the invention has been designed to be capable of withstanding high pressures, for instance 0 1 of the order of 1,000 p.s.i.

m* I In the illustrated embodiment, the diameter of the portion 52 is 25.05 millimetres and that of 0 the portion 50 is 18.9 millimetres. The pressure equalisation duct 58 is 0.5 millimetres in diameter.

Many modifications will be apparent to those skilled in the art without departing from the spiiit and scope of the invention. l 1 t

Claims

1. An extinguisher head assembly comprising a body having first and second bores, the first bore being of a smaller diameter than the second, the first bore being in use coupled to a source of extinguishant under pressure, said second bore forming part of a normally closed chamber, piston means having first and second portions slidably n a mounted in said first and second bores respectively, release means for releasing pressure in the chamber, ooo said piston means including a pressure equalization opening therethrough to equalize pressure, in use, in 0 0 the first and second bores, said body including an O 0 outlet port which is closed by the piston means until the release means is operated to release pressure in Sa the chamber whereby the piston means moves under the 0 00' influence of the pressure of the extinguishant in the o first bore to thereby open the outlet port and permit the extinguishant to pass through the outlet port.

2. An assembly as claimed in claim 1 including a cap mounted on the body, said cap defining part of the periphery of the chamber.

3. An assembly as claimed in claim 1 or 2 wherein sai piston means comprises a stepped piston.

4. An assembly as claimed in claim 3 wherein the first and second portions of the stepped piston include respective O-rings.

An assembly as claimed in claim 3 or 4 wherein the stepped piston includes a piston recess t L 8 extending from the end face of the first portion thereof and said pressure equalization opening extends from the end face of the second portion and communicates with said piston recess.

6. An assembly as claimed in claim 5 as appended to claim 2 wherein including sealing means to seal said equalization opening when the piston means has moved to a position in which said outlet port is open whereby the pressure of the extinguishant acts on the piston means to keep it in cd a position in which said port is open.

7. An assembly as claimed in claim 6 wherein o said sealing means comprises an O-ring let into the end face of the second portion of the piston and o surrounding said equilization opening.

8. An assembly as claimed in any preceding claim wherein said release means comprises a solenoid S° valve, poppet valve or ball valve.

9. An assembly as claimed in claim 2 or any one of claims 2 to 7, as appended to claim 2 wherein said o cap includes a bursting disc and wherein said release means comprises a hollow pin for perforating the disc.

An assembly as claimed in any preceding claim wherein the body includes openings to the first bore for receipt of pressure relief means, pressure guage and/or filling valve.

11. An extinguisher head assembly substantially as hereinbefore described with reference to the accompanying drawings. a L.[ I 1 9

12. A fire extinguisher including a pressure vessel and an extinguisher head assembly as claimed in any one of the preceding claims mounted thereon, said extinguisher including a tube which extends from the interior of said vessel to the body and communicates with said first bore. 00 0o a,00n o. 0 004 0 00 0 S00 I. 444 *0 0 "'4 4 0. DATED this 26th day of September, 1988 WESTFIRE PTY. LTD. By its Patent Attorneys DAVIES COLLISON o 44r 4 44 r