CA1122099A - Fire extinguishers - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A fire extinguisher of the type comprising a burst-able container adapted to provide; a high mass flow rate of discharged extinguishant is provided with venting means so adapted to direct the flow of extingulshant from the container that the reaction forces upon the container during discharge of extinguishant compensate one another to reduce the resultant force upon the con-tainer.

Description

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TITLE OF THE INVENTION
I~IPROVEMENTS IN AND RELATING TO FIRE EXTINGUISHERS
BACKGROUND OF TIIE INVENIION
In fire suppression systems requiring a high mass flow rate of extinguishant, for example in order to quench an incipient fire in the pre-sence of a highly volatile liquid fuel, it is known to achieve the required rapid discharge of extinguishant from a container, by opening a relatively large bursting diaphragm fitted to a venting port of the container, thus permitting the contents to be ejected either by the vapour pressure of the extinguishant, or by the pressure derived from other means, for example an additional gas filling. Burstable containers of this kind have been proposed for use, for example, in aircraft fire suppression systems. However, such burstable containers have the disadvantage that the high mass flow rate of the fire extinguishant discharged therefrom can cause unduly high reaction forces to be imposed upon the container and thus upon the mountings by which ` it is secured in, for example, an aircraft, which reaction forces may possibly lead to failure of the mountings and damage to the adjacent structure of the aircraft.
SUMMARY OF T~E INYENTION
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It is an object of the present invention to eliminate, or at least to reduce, the above-mentioned disadvantage of the known fire extinguishers referred to.
` The present invention provides a fire extinguisher comprising a `- container providing a source of extinguishant, a burstable diaphragm defining a part of said container and permitting, upon bursting thereof, a high mass flow rate of extinguishant from the container, wall means arranged in spaced, facing relationship to said diaphragm and being at least substantially equal in area to said diaphragm whereby said wall means provides an impingement surface for a jet of extinguishant released upon bursting of said diaphragm, ; 30 and means locating said wall means in fixed relation to said container whereby B

ll~Z~g9 the reaction force upon said container due to the discharge of the jet of extinguishant therefrom is substantially balanced by the reaction force on said wall means, due to the impingement of the jet extinguishant thereon, the said locating means defining lateral outlet ports between said diaphragm and said impingement surface, said outlet ports occupying the major part of the peripheral space between said diaphragm and said impingement surface to permit substantially unimpeded dispersal of extinguishant deflected by said impingement surface, and the number, size and position of the said discharge ports being balanced in such a manner that the reaction forces upon said container due to the flow of extinguishant from the discharge ports substan-tially balance one another.
BRIEF DESCRIPTION OF THE DRA~INGS
The invention is illustrated by way of example in ~3-. ~
V
'' ,............................ i~'~Z~g9 thc accompal~ing dra~ings, in whic:h:
Figure 1 is a side elevation of a fire extinguisher in accordance wi-th one embodiment of -the present lnven-tion, Figure 2 is a view in the direc-tion of the arrow A of Figure 1, Figure 3 is a view s:imilar to.~igure 1 of a fur-ther ~ embodiment of extinguisher in accordanoe with -the inven-~ tion, and :: 10 Figure 4 ls a view in the direc-tion of the arrow .~ B of Figure 3.
` ~ DESCRIPTION OF T:~IE PRE ERRE:D EMBODIMENT
.` Referring to Figures 1 and 2 of -the drawings, a~ fire extinguisher in accordance with one embodiment of ~ .
- 15 the invention comprises a hollow bulb 1 defining a con~
tainer for fire extinguishant. Attaohed to the bulb 1 are a lu~ion 2, providing-for connectlon of the.extin~
guisher into an electrical control circuit of kno~m type . not further illus-trated, and a flange extlnguishant ~ 20 discharge port 3 closed, in known manner, by means of~
: ~ . a burstabIe diaphragm (not shown). r~he internal con~struction of the ex-tinguisher is of generally known :
type, and -therefore not illustrated or referred -to :
in more detail. Briefly, however, upon receipt of an appropriate con-trol signal via the union 2, the dia-phragm closing -the discharge port 3 is ruptured~ for example by means o~ an explosive charge located within the bulb 1, to release the contents of the extinguisher.
r~he discharge port ~ is provided with an end cap 4, having lateral discharge orifices 5 for extinguishantO

: - 4 -' :~:

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1~2;~99 ~hus in accordance ~ith the inven-tion~ the end cap 4 provides for deI`lection of the fire extinguishant -through the ori~ices 50 The discharge orifices 5 are regularly spaced aro~md the periphery o~ the end cap 4, and thus a ~60 radial dispersal o~ extinguisharlt is achieved, with substantially zero resul-tant -reaction force being imposed upon the body of the extinguisher.
~he end cap defines a wall means 7 which is dis- ;
posed in spaced, facing relationship ~Lth the diaphragm -~ 10 closing port 3 and, as can be seen in -the drawing, the wall means is at least of equal area to said diaphragm.
~ ~ The wall means defines an impingement surface 8- ~`gainst `~ which the extingulshant, exiting the container, strikes, ` - thus generating a substantially equal and opposite force , . -to that generated by the extinguishant on the container as it exits that container.
- ~ Although the discharge orifices 5 of the end cap `-` 4 are as illus-trated in Figures ~ and 2 of such relative proportions that a subs-tantially radial 360 dls-tri~
,, -bu-tion of discharged extinguishant is obtained, i-t will~
be appreciated that by adjusting the arrangement and relative dimensions of the discharge orifice 5, the distribution pattern of the extinguishant can be modi-fied in any desired manner. For example, by increasing~
the axial length of the orifices 5, a greater dispersion of extinguishan-t in the axial direction of -the end cap 4 can be achieved. Also~ as illustrated in Figures and 4, auxiliary baffles 6 may be provided for deflec-tion of the extin~lishan-t in an axial direction.
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Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A fire extinguisher comprising a container providing a source of extinguishant, a burstable diaphragm defining a part of said container and permitting, upon bursting thereof, a high mass flow rate of extinguishant from the container, wall means arranged in spaced, facing relationship to said diaphragm and being at least substantially equal in area to said dia-phragm whereby said wall means provides an impingement surface for a jet of extinguishant released upon bursting of said diaphragm, and means locating said wall means in fixed relation to said container whereby the reaction force upon said container due to the discharge of the jet of extinguishant therefrom is substantially balanced by the reaction force on said wall means, due to the impingement of the jet extinguishant thereon, the said locating means defining lateral outlet ports between said diaphragm and said impinge-ment surface, said outlet ports occupying the major part of the peripheral space between said diaphragm and said impingement surface to permit substan-tially unimpeded dispersal of extinguishant deflected by said impingement surface, and the number, size and position of the said discharge ports-being balanced in such a manner that the reaction forces upon said container due to the flow of extinguishant from the discharge ports substantially balance one another.

2. A fire extinguisher as claimed in Claim 1, wherein there is an even number of such outlet ports regularly angularly spaced about the periphery of said wall means.

3. A fire extinguisher as claimed in Claim 2, wherein said outlet ports are associated with deflector plates deflecting said extinguishant axially the said deflector plates of alternate ports being angled in opposed directions, whereby the axial reaction forces due to discharge of extinguish-ant from alternate ones of said outlet ports are balanced by oppositely acting axial forces due to discharge of extinguishant from the remaining ports.

4. A fire extinguisher as claimed in Claim 1 or Claim 2, in which said diaphragm and said wall means are both of circular form having substantially equal diameters.