US3747685A - Fire extinguishers - Google Patents

Abstract

An automatic chemical-type fire extinguisher has a container for containing the extinguishant and a thermally operative valve for discharging the extinguishant in the event of fire. The container is mounted from an overhead support by an arrangement including two relatively slidable members one attached to the overhead support and one to the container. A spring acts between the two slidable members and opposes the weight of the container and extinguishant. On partial or complete loss of extinguishant, the weight becomes insufficient to oppose the spring, and the resultant relative movement of the members actuates electrical contacts to signal an alarm.

Description

2/19s0 Ashcraft ..169/26 United States Patent 1 1 1111 3,747,685 McCuilocli July 24, 1973 FIRE EXTINGUISHERS 3,446,286 5 1969 Kreidler; 169/26 Inventor: Alister L. McCullochVictoria, 1,936,007 ll/l933 Carroll 169/23 Australia Primary Examiner-M. Henson Wood, Jr.

I Assistant ExaminerMichael Y. Mar 73 A i Graviner (colnbmok) L Attorney-Jarrett Pass Clark, Franklin M. Crouch and London, England Gordon R. Coons 22 Filed:' Oct. '28, 1971 R 5 T [21] Appl. No.: 193,274 7] ABS ACT An automatic chemical-type fire: extinguisher has a container for containing the extinguishant and a ther- [30] Foreign Apphcnion Priority Data mally operative valve for discharging the extinguishant OCL 29, Australia 3027 in event of fire The container is mounted from an overhead support by an arrangement including two rel- US. Cl. atively slidable members one attached to the overhead Int. Cl-

u port and one to the containef A spring acts beof Search .nlln... u 2, 23, 26, tween the two lidable members and opposes the 169/31 R; 222/39 weight of the container and extinguishant. On partial or complete loss of extinguishant, the weight becomes in- References cued sufficient to oppose/the spring, and the resultant rela- V UNITED STATES PATENTS tive movement of the members actuates electrical con- 2,670,194 2/1954 llansson 1 9 23 ux tam to Signal an 1 l2/l970 Balmes, Sr.. 169/31 R 7 m 2 Drawingmgures BACKGROUND OF THE INVENTION The invention relates to fire extinguishers.

Fire extinguishers for permanent or semi-permanent mounting over an area to be protected are known. In one such form, such fire extinguishers comprise one or more sprinkler-type discharge heads, often mounted in the ceiling of a room, and connected to a water supply line which is maintained under pressure. Thermally operative valves allow the water to discharge in the event of an abnormal rise in ambient temperature.

However, such extinguishers are not suitable, and may in fact be dangerous, for extinguishing burning liquids, particularly petroleum products, and chemicals or electrical fires. For extinguishing such fires, fire extinguishers arranged to discharge chemical extinguishants are known. For automatically protecting a particular area, such extinguishers may, for example, be mounted in the ceiling over the area. Instead of being connected to a mains water supply under pressure, each extinguisher has a separate container or tank for holding the chemical extinguishant, and a sprinkler-type discharge head through which the extinguishant is discharged in the event of abnormally high temperature by a thermally sensitive valve.

Such chemical-type extinguishers may be used to protect areas where automatic untended equipment is located, suchaselectrical switch gear, underground electrical and other equipment and the like, and particularly, through not exclusively, in such applications the need arises forsome form of remote indication to be given when and if the chemical extinguishant has be come partially or completely exhausted as by leaking or after discharge in the eventof a fire.

. It is therefore an object of the invention to provide an improved fire extinguisher of the chemical type.

It isa further object of the invention to provide an improved fire extinguisher capable of signalling when there has been partial or complete loss of extinguishant. I

BRIEF SUMMARY OF THE INVENTION DESCRIPTION OF THE DRAWINGS A fire extinguisher embodying the invention will now be described, by way of example only, with reference to the accompanying drawing in which:

FIG. I' is a side view of the extinguisher mounted from a ceiling; and

FIG. 2 is a crosssectional view of part of the extinguisher of FIG. 1, taken on the line lI-Il of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT The fire extinguisher illustrated uses a chemical extinguishing fluid such as bromochlorodifluoromethane (B.C.F.), and is intended for extinguishing burning liquids, particularly petroleum products, and chemicals or electrical fires. The extinguisher comprises a rechargeable container 1, containing the extinguishant (between 3 and 30 pounds, for example), suspended from the ceiling 2 in the area to be protected by a bracket 3 through the intermediary of an alarm unit 4 to be described in detail below. An outlet 5 from the container is connected to a sprinkler discharge head 9 through a thermally operative valve. The valve comprises an outlet seal (not shown) which is held over the opening 5 by a pair of lever arms 6 and 7 which are held in the position illustrated by a fusible link 8.

In operation, an abnormal rise in temperature, such as due to a fire in the area to be: protected, fuses the link 8, whereupon the arms 6 and 7 separate and, in so doing, displace the outlet seal so as to allow the extinguishant under pressure in the container 1 to exit via the outlet 5 and the discharge head 9.

Instead of the arms 6 and 7 and the fusible link 8, the outlet seal may be held in position by a quartz-alcohol bulb (not shown) which is arranged to collapse and to displace the outlet seal when the ambient temperature becomes abnormally high.

A wire guard 10 serves to protect the discharge head from being knocked and accidentally released.

The alarm unit 4 comprises a tubular member 11 which is screw-mounted to the ceiling bracket 3. A contact base 12, supportingelectrical contacts 12a, is secured within the member 11. A plunger .13 is at tached to the top of the container 1 and is slidable within the tubular member 11. The plunger 13 hasan electrically conductive head, and a compression spring 14 acts between the underside of this head and an inwardly directed annular flange at the bottom of the tubular member 11. The spring rate is such that the container 1, when full of extinguishant, has sufficient weight to compress the spring and to create a gap between the contacts 12aand the plunger 13. When the container 1 is at least partially empty (due to use or leakage), the force exerted by the spring is able to lift the plunger 13 so that its electrically conductive head bridges the contacts 12a. I

Wires (not shown) are connected to the contacts through a grommet or hollow screw 15, and enable actuation of an alarm circuit in response to bridging of the contacts.

In a modification (not shown), upward movement of the plunger I3 in response to emptying of the container 1 is arranged to open-circuit (instead of short-circuit) a set of contacts, so as to initiate the alarm circuit.

The extinguisher illustrated is particularly advantageous for use in remote locations, and enables a distant indication or alarm to be given when the extinguisher has exhausted itself by leaking or after activation by a fire. Conveniently, the electrical systems ofa series of extinguishers (similar to that illustrated) protecting automatic switch gear, computers in cubicles or underground and the like for example, may be included in a controlpanel remote from the extinguishers, and it is ;thus a simple procedure to inspect the panel to ascertain the state of the extinguishers.

. Although the extinguisher shown has been illustrated as mounted from a ceiling, it will be appreciated that theextinguisher may be otherwise mounted, such as from a wall for example.

It will be appreciated that the extinguisher may use any suitable type of extinguishant, such as in liquid, powder or foam form for example.

Many modifications can be made to the invention without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. A fire extinguisher, comprising a container for holding an extinguishant,

means in communication with the interior of the container for discharging the extinguishant from the container in the event of a fire,

mounting means for supporting the weight, of the container and extinguishant if any therein from an overhead support and including first and second members attached to each other for relative movement and one attached to the overhead support and the other attached to the container for movement with the container relative to the said one member when the said weight is reduced by at least partial loss of extinguishant, and spring means having a predetermined rate and acting between the first and second members to bias them, against the said weight, towards a first relative positional setting, the predetermined spring rate being such that the weight of the said container when full of the extinguishant holds the members in a second relative positional setting against the spring force, and

signalling means mounted to be actuated when the members move from the second relative positional setting into the first relative positional setting as the result of reduction of the said weight.

2. An extinguisher according to claim 1, in which the said extinguishant is a chemical extinguishant, and in which the container stores the extinguishant under pressure.

3. An extinguisher according to claim 1, in which the said discharge means comprises a discharge head and passage means providing flow communication between the container and the discharge head, and thermally responsive valve means in the said passage means for closing off the passageway until the ambient temperature rises above a predetermined level.

4. An extinguisher according to claim 1, in 'which the signalling means comprises electrical contact means mounted to be actuated when the members move from the said second relative positional setting into the first relative positional setting.

5. An extinguisher according to claim 4, in which the first and second members are relatively slidable.

6. An extinguisher according to claim 5, in which the first member comprises an open-ended tubular member supported from the overhead support,

the electrical contact means comprises a plurality of electrical contacts supported within the tubular member,

the second member comprises a member attached to the container and extending into the open end of the tubular first member for sliding movement therein and defining an electrically conductive surface for bridging the said contacts,

- the spring means comprises a compression spring acting between the tubular first member near its said open end and the second member and biasing the second member towards the contacts against the action of the said weight.

7. An extinguisher according to claim 4, in combination with remotely located electrical circuit means, means electrically connecting the circuit means to the said contact means for activating the circuit means in response to actuation of the contact means, and alarm means connected to produce an alarm indication in response to actuation of the contact means.

Claims (7)

1. A fire extinguisher, comprising a container for holding an extinguishant, means in communication with the interior of the container for discharging the extinguishant from the container in the event of a fire, mounting means for supporting the weight, of the container and extinguishant if any therein from an overhead support and including first and second members attached to each other for relative movement and one attached to the overhead support and the other attached to the container for movement with the container relative to the said one member when the said weight is reduced by at least partial loss of extinguishant, and spring means having a predetermined rate and acting between the first and second members to bias them, against the said weight, towards a first relative positional setting, the predetermined spring rate being such that the weight of the said container when full of the extinguishant holds the members in a second relative positional setting against the spring force, and signalling means mounted to be actuated when the members move from the second relative positional setting into the first relative positional setting as the result of reduction of the said weight.

2. An extinguisher according to claim 1, in which the said extinguishant is a chemical extinguishant, and in which the container stores the extinguishant under pressure.

3. An extinguisher according to claim 1, in which the said discharge means comprises a discharge head and passage means providing flow communication between the container and the discharge head, and thermally responsive valve means in the said passage means for closing off the passageway until the ambient temperature rises above a predetermined level.

4. An extinguisher according to claim 1, in which the signalling means comprises electrical contact means mounted to be actuated when the members move from the said second relative positional setting into the first relative positional setting.

5. An extinguisher according to claim 4, in which the first and second members are relatively slidable.

6. An extinguisher according to claim 5, in which the first member comprises an open-ended tubular member supported from the overhead support, the electrical contact means comprises a plurality of electrical contacts supported within the tubular member, the second member comprises a member attached to the container and extending into the open end of the tubular first member for sliding movement therein and defining an electrically conductive surface for bridging the said contacts, the spring means comprises a compression spring acting between the tubular first member near its said open end and the second member and biasing the second member towards the contacts against the action of the said weight.

7. An extinguisher according to claim 4, in combination with remotely located electrical circuit means, means electrically connecting the circuit means to the said contact means for activating the circuit means in response to actuation of the contact means, and alarm means connected to produce an alarm indication in response to actuation of the contact means.

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