Fire extinguisher

Abstract

A fire extinguisher having an agent chamber wherein a pressurised fire extinguishing agent is stored, a discharge port, and a solid propellant assembly for operatively propelling and discharging the fire extinguishing agent from the fire extinguishing agent chamber such that, in use and in an inoperative state of storage of the fire extinguisher with the valve in a closed position, a coil spring is compressed by a force of the pressurised extinguishing agent against a piston, and upon opening of the valve and decompression of the fire extinguishing agent chamber, the coil spring decompresses and propels the fire extinguishing agent from the chamber by reverse force of the piston acting against the fire extinguishing agent.

Description

[0001] Fire Extinguisher

[0002] This invention relates to a fire extinguisher.

[0003] The invention is expected to be advantageously applicable to fire extinguishers used aboard aircraft, for example on passenger and cargo airlines. Accordingly, such applications should particularly, but not exclusively, be borne in mind when considering this specification.

[0004] Background of the Invention:

[0005] Traditionally, fire extinguishers comprise a pressure vessel or chamber containing a pressurized extinguishing agent and a pressurised fluid propellant that discharges the extinguishing agent in use. Fire extinguishers are typically of either the store-pressured or the cartridge-operated kind:

[0006] For store-pressured fire extinguishers, the pressurised fluid propellant is stored in the same chamber as the extinguishing agent, and the pressurised fluid propellant type depends on the extinguishing agent. For example, for dry-chemical extinguishing agents a pressurised nitrogen propellant is often deployed, whereas pressurised air may be used as propellant for water and foam type extinguishing agents.

[0007] For cartridge-operated extinguishers, the propellant is contained in a separate cartridge that is punctured before discharge and thereby exposes the propellant to the extinguishing agent.

[0008] Fire extinguishers of the kind contain a pressurised fluid propellant and upon use, the extinguishing agent is discharged by the pressurised fluid propellant. However, fire extinguishers of the kind pose a safety risk when used in pressurised environments, for example on board pressurised aircraft.

[0009] The inventor has identified a need for a fire extinguisher mechanism for use in pressurised environments and the present invention aims to provide such an improved extinguisher. Summary of the Invention:

[0010] In accordance with the invention, broadly, there is provided a fire extinguisher comprising a pressurised extinguishing agent that is discharged by a solid propellant mass in use.

[0011] According to a first aspect of the invention there is provided a fire extinguisher which includes: a fire extinguishing agent chamber wherein a pressurised fire extinguishing agent is stored; a discharge port in fluid flow communication with the fire extinguishing agent chamber; and a solid propellant assembly for operatively propelling and discharging the fire extinguishing agent from the fire extinguishing agent chamber on opening of a valve of the discharge port of the chamber.

[0012] The solid propellant assembly may include a solid propellant mass attached to biasing means.

[0013] The biasing means may include mechanical biasing means for example a coil spring.

[0014] The solid propellant mass may include a piston. The piston may include a seal, for example a ring seal.

[0015] In an inoperative state of storage of the fire extinguisher, and with the valve in a closed position, the coil spring is compressed by a force of the pressurised extinguishing agent against the piston. In use upon opening of the valve and accompanying decompression of the fire extinguishing agent chamber, the coil spring releases (decompresses) and the extinguishing agent is propelled from the chamber by reverse force of the piston acting against the extinguishing agent.

[0016] In a preferred embodiment, the fire extinguishing agent chamber may include a cylinder wherein the solid propellant assembly is located.

[0017] In a preferred embodiment, the fire extinguisher comprises more than one fire extinguishing agent chambers and hence more than one cylinder each comprising a solid propellant assembly. In such an embodiment, the fire extinguisher may include a manifold in fluid flow communication with the discharge ports of the more than one cylinders.

[0018] The fire extinguisher may include any one or more of a coil spring retainer mechanism, and a coil spring release mechanism.

[0019] The retainer mechanism may include a connecting rod of which one end is secured or mounted fast with the piston, and another end is attached to a wall of the cylinder. The retainer mechanism may include a spring compression adjuster for setting a static spring compression.

[0020] The fire extinguisher may include a valve actuator for opening and closing the valve.

[0021] Advantageously, the valve actuator may be operated by a hand lever, and the fire extinguishing agent chamber may include a polymer casing.

[0022] The invention is now described, by way of non-limiting example, with reference to the accompanying drawings.

[0023] Drawings:

[0024] In the drawings,

[0025] Figure 1 shows a schematic side sectional view of a fire extinguisher according to one aspect of the invention.

[0026] Figure 2 shows a front view of the fire extinguisher of figure 1 according to another aspect of the invention.

[0027] Detailed Description of the Invention:

[0028] In figure 1, reference numeral (100) denotes a side sectional view of a fire extinguisher according to one embodiment of the invention.

[0029] The fire extinguisher (100) comprises three fire extinguishing agent chambers of which one is denoted by numeral (106) wherein a pressurised fire extinguishing agent (114) is stored; a discharge port (116) in fluid flow communication with cylindrical fire extinguishing agent chambers (106), (118) and (120); and a solid propellant assembly (108) for operatively propelling and discharging the fire extinguishing agent (114) on opening of a valve (102) of the discharge port (116) of the fire extinguishing agent chambers (106), (118) and (120).

[0030] In this embodiment of the invention, the solid propellant assembly (108) comprises a solid propellant mass in the form of a piston (107) having a ring seal (110), the piston (107) being attached to biasing means in the form of a mechanical coil spring (122).

[0031] In an inoperative state of storage of the fire extinguisher (100), and with the valve in a closed position, the coil spring (122) is compressed by a force of the pressurised extinguishing agent (114) against the piston (107). In use upon opening of the valve (102) and accompanying decompression of the fire extinguishing agent chamber (106), the coil spring (122) releases (decompresses) and the extinguishing agent (114) is propelled from the chamber by reverse force of the piston (107) acting against the extinguishing agent (114).

[0032] The fire extinguisher (100) includes a coil spring retainer mechanism in the form of a connecting rod (112) of which one end is secured or mounted fast with the piston (107), and another end is releasably attached to a wall or cap (113) of the cylinder.

[0033] Turning to figure 2, reference numeral (200) denotes an external side view of the fire extinguisher (100) of figure 1 according to another embodiment of the invention. The fire extinguisher (200) is provided with a polymer casing body (202) and a hand operated lever (204).

Claims

Claims:

1. A fire extinguisher comprising a pressurised extinguishing agent that is discharged by a solid propellant mass in use.

2. A fire extinguisher comprising: a fire extinguishing agent chamber wherein a pressurised fire extinguishing agent is stored; a discharge port in fluid flow communication with the fire extinguishing agent chamber; and a solid propellant assembly for operatively propelling and discharging the fire extinguishing agent from the fire extinguishing agent chamber on opening of a valve.

3. The fire extinguisher of claim 2 wherein the solid propellant assembly includes a solid propellant mass attached to biasing means.

4. The fire extinguisher of claim 3 wherein the solid propellant mass includes a piston.

5. The fire extinguisher of claim 3 or claim 4 wherein the biasing means includes a mechanical biasing means.

6. The fire extinguisher of claim 5 wherein the mechanical biasing means is a coil spring such that, in use and in an inoperative state of storage of the fire extinguisher with the valve in a closed position, the coil spring is compressed by a force of the pressurised extinguishing agent against the piston, and upon opening of the valve and decompression of the fire extinguishing agent chamber, the coil spring decompresses and propels the fire extinguishing agent from the chamber by reverse force of the piston acting against the fire extinguishing agent.

7. The fire extinguisher of claim 6 of which the fire extinguisher agent chamber includes a cylinder wherein the solid propellant assembly is located.

8. The fire extinguisher of claim 7 which includes a coil spring retainer mechanism and a coil spring release mechanism.

9. The fire extinguisher of claim 8 of which the retainer mechanism includes a connecting rod of which one end is secured to the piston and another end is attached to a wall of the cylinder.

10. The fire extinguisher of claim 9 wherein the retainer mechanism includes a spring compression adjuster for setting a static spring compression.

11. The fire extinguisher of claim 10 which includes a valve actuator for opening and closing of the valve.

12. The fire extinguisher of claim 11 wherein the piston includes a seal such as an annular seal.

13. The fire extinguisher of claim 12 wherein the valve actuator is operated by a hand lever and the fire extinguishing agent chamber has a polymer casing.

14. The fire extinguisher of any one of the preceding claims that comprises a plurality of fire extinguishing agent chambers having corresponding solid propellant assemblies.

15. The fire extinguisher of claim 14 which includes a manifold in fluid flow communication with the discharge port.

16. A fire extinguisher as claimed in claim 2, substantially as herein described and illustrated.

17. A new fire extinguisher substantially as herein described.

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