GB2164252A - Fire extinguishing apparatus - Google Patents

Abstract

A nozzle assembly 20 is connected to receive extinguishant under pressure from a vessel 10 when the discharge mechanism 12 of the latter is actuated. The extinguishant acts on the face 66 of a piston part 34 and exerts sufficient pressure to move the latter against a spring 52. A hollow sleeve 38, which receives the extinguishant through a small opening 60, thus slides in a section 26 response to the piston movement and holes 42 and 44 now protrude at the end of section 26 which was previously closed off by a cap 40 and end plate 46. In this way, the nozzle is normally completely closed off from pollution etc. in the external environment but is opened automatically by the pressure of the discharging extinguishant. <IMAGE>

Description

SPECIFICATION Fire extinguishing and explosion suppression arrangements The invention relates to the extinguishing of fires and suppression of explosion. In this Specification hereafter, references to fires and to the extinguishing of fires are intended to include references to explosions and the suppression of explosions.

Fire extinguishers are well known in the form of bottles or other sealed vessels containing extinguishant under pressure and having discharge means of various types. For example, it is known to provide discharge nozzles which are normally closed off by a barrier made of suitable material which is arranged to be ruptured or fractured when it is desired to release the extinguishant. Rupture or fracture of the barrier (which may be a thin metal diaphragm for example) may be arranged to be carried out by an explosive device which is electrically detonatable.

According to the invention, there is provided a fire extinguishing arrangement, comprising storage means for storing extinguishant under pressure, housing means defining an exit nozzle open to the outside environment, closure means for the nozzle movable between a normal, closed position in which it closes off the nozzle from the outside environment and an open position in which the nozzle is open to the outside environment, a piston slidable within the housing means and connected to the closure means whereby sliding of the piston in a predetermined direction moves the closure means from the closed position to the open position, the closure means commencing to open the nozzle as soon as the piston starts to slide in the predetermined direction, means connecting the housing means to the storage means for receiving the extinguishant under pressure from the storage means and applying the extinguishant under pressure to the piston whereby to slide it in the predetermined direction, and a through passageway passing through the piston for feeding the extinguishant under pressure to and through the exit nozzle when the latter is opened by the closure means.

According to the invention, there is further provided a fire extinguishing arrangement, comprising: a vessel storing extinguishant under pressure; a discharge mechanism connected to the vessel and which is releasable so as to allow extinguishantto exit from the vessel under pressure; at least one nozzle assembly; and pipe means connecting the nozzle assembly downstream of the discharge mechanism so as to receive extinguishant under pressure from the vessel through the discharge mechanism when the latter is released; the nozzle assembly comprising a cylinder having its interior connected to receive the extinguishant via the pipe means, a piston slidable in the cylinder, spring means biasing the piston into a rest position, the piston defining a face which is acted on by the extinguishant received in the cylinder so as to move the piston from the rest position, means defining a nozzle which is open to the outside environment, a passageway passing through the piston from and open to its said face and leading towards the nozzle, closure means acting between the passageway and the nozzle and movable between a closed position in which it closes the passageway off from the nozzle and an open position in which it connects the passageway to the nozzle, and means directly connecting the closure means to the said piston whereby movement of the piston from the rest position moves the closure means from the closed position to the open position, the closure means commencing to open the nozzle as soon as the piston starts to move from the rest position.

Afire extinguishing arrangement embodying the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawing in which: Fig. 1 shows part of the arrangement in side view and part of it in cross-section; and Fig. 2 corresponds to part of Fig. 1 but showing the arrangement in an operated state.

As shown in Figure 1,the arrangement comprises a fire extinguishant bottle 10 containing suitable extinguishant, which may be powder, gas or liquid, which is stored in the bottle under pressure. The bottle 10 has a discharge outlet 12 which may be of any conventional form and will not be described in detail. For example, it may comprise a rupturable diaphragm which closes off an exit from the vessel 10 and is sufficiently strong to resist the pressure of the extinguishant. An electrically detonatable explosively operated mechanism 14 is provided (which again may be of conventional form). When electrically energised by means of leads 16, the explosive is detonated and a piston is rapidly urged forward and ruptures the closure. The extinguishant now exits rapidly under pressure.

As shown in Figure 1, the exit from the vessel 10 is connected by a pipe 18 to a nozzle assembly indicated generally by the reference 20.

The nozzle assembly 20 is generally cylindrical and comprises a rigid casing 22 having a large bore section 24 and a smaller bore section 26. Its large bore section 24 is closed off by a cover 28 which is held in position by circumferentially arranged screws 30. A cylindrical slider 32 slides within the casing 22. The slider 32 has an enlarged end in the form of a hollow piston 34 which is dimensioned to be a substantially fluid-tight sliding fit within the large bore section 24 of the casing 20, the degree to which it can slide to the left (as viewed in Figure 1) being limited by a circumferentially arranged shoulder 36. Instead of being dimensioned to be a fluid-tight sliding fit, piston 34 may be arranged to carry an O-ring seal to achieve the same effect.

The piston 34 is integral with a sleeve 38 which is a close sliding fit within the small bore section 26 of the casing 22. The sleeve 38 has an end cap 40 and two holes 42 and 44 arranged symmetrically in its circumference immediately adjacent the cap 40. An end plate 46 is rigidly attached to the cap 40 by a screw 48. The end plate 46 is of greater diameter than the cap 40 and matches the outside diameter of the small bore section 26 of the casing 22. A sealing ring 50 is attached to the underside of the plate 46.

A compression spring 52 surrounds an end region of the sleeve 38 and acts between an end wall 54 of the large bore section 24 of the casing 22 and the outside face of the piston 34.

The pipe 18 from the vessel 10 is sealingly attached to the cover 28 by a screwed connection 56 which defines a relatively large diameter opening 58.

The piston 34 has a relatively small nozzle 60 which leads to the interior of the sleeve 38.

The extinguisher arrangement illustrated is primarily intended to be mounted in a fixed position. For example, the nozzle assembly 20 may be mounted within a wall indicated generally at 62 so that the small bore section 26 protrudes into an area 64 in which the fires to be extinguished are expected to arise. The bottle 10 is mounted in any suitable way, and the pipe 18 may be of any reasonable length. In fact, the bottle 10 may be arranged to feed more than one nozzle assembly similar to the assembly 20, in which case of course the pipe 18 wouldbe a branched pipe connecting the bottle 10 to each of the nozzle assemblies.

In use, the bottle 10 is normally maintained in its sealed state by the closed discharge means 12. In addition, however, the nozzle assembly 20 is held in the closed position by the spring 52. The spring ensures that the slider 32 is held in the position illustrated, that is, at the extreme right hand end of the casing 22, so that the plate 46 and the sealing ring 52 close off the open end of the section 26. The path from the pipe 18, through the opening 58 and the nozzle 60 to the holes 42 and 44, is thus closed off.

When the extinguishant is to be discharged, the discharge mechanism 12 is electrically energised in the manner already explained, either automatically or manually, and extinguishant under pressure is released through the pipe 18 and hole 58 into the interior 65 of the piston 34. The pressure, acting on the relatively large surface area of the end wall 66 of the piston 34 produces sufficient force to overcome the force of the spring 52 and the whole slider 32 moves substantially without any delay to the left, as viewed in Figure 1, until its movement is arrested by contact with the shoulder 36. The sleeve 38 thus correspondingly moves to the left so that the plate 46 moves away from the end of the section 26 of the casing and the holes 42 and 44 are clear of the end of the section 26, all as shown in the part view of Figure 2.It will be noted that the sleeve 38, being directly connected to the piston 34, commences to move as soon as the piston starts to slide, and that such movement immediately starts to open the holes 42 and 44. The extinguishant under pressure is therefore substantially discharged instantaneously through the small bore 60 and the holes 42 and 44.

In this way, therefore, the actual discharge nozzle (in fact provided by the holes 42 and 44) and the mechanism and passageways leading to that nozzle are completely sealed off until extinguishant is to be discharged and there is no possibility of ingress of dirt, moisture or pollution from the area 64 which might block, partially or completely, or damage a discharge arrangement which was completely open.

The arrangement illustrated is thus particularly suitable for use in environments where there is likely to be pollution of a type which might block a completely open nozzle. However, although the nozzle is completely closed until extinguishant discharge is to take place, the opening of the nozzle takes place automatically when extinguishant discharge occurs. No additional action has to be taken to open the nozzle, that is, only the normal discharge action needs to be taken. The nozzle assembly 20 can thus be fitted to normal types of extinguisher without the need for providing additional release mechanism. It will also be appreciated that the spring 52 ensures that the nozzle assembly closes automatically when discharge is completed. It is therefore only necessaryforthe bottle 10to be replenished. No action needs to be taken with the nozzle assembly.

It is necessary of course to ensure that the dimensions of the piston 34 and the rate of the spring 52 are such, in relation to the pressure of the extinguishant in the bottle 10, that sufficient force is available to move the slider 32 into the open position, and to hold it there during discharge of the extinguishant. The operating pressure required by each nozzle is set sufficiently low so that, where several nozzle assemblies 20 are connected to the same bottle 10, the extinguishant pressure available is sufficient to open all the nozzle assemblies.

Claims (9)

1. A fire extinguishing arrangement, comprising storage means for storing extinguishant under pressure, housing means defining an exit nozzle open to the outside environment, closure means for the nozzle movable between a normal, closed position in which it closes off the nozzle from the outside environment and an open position in which the nozzle is open to the outside environment, a piston slidable within the housing means and connected to the closure means whereby sliding of the piston in a predetermined direction moves the closure means from the closed position to the open position, the closure means commencing to open the nozzle as soon as the piston starts to slide in the predetermined direction, means connecting the housing means to the storage means for receiving the extinguishant under pressure from the storage means and applying the extinguishant under pressure to the piston whereby to slide it in the predetermined direction, and a through passageway passing through the piston for feeding the extinguishant under pressure to and through the exit nozzle when the latter is opened by the closure means.

2. An arrangement according to claim 1, including spring means urging the closure means into the closed position, the force of the spring means being such that it is overcome by the force generated by the pressure of the extinguishant acting on the piston.

3. An arrangement according to claim 1 or 2, in which the said passageway through the piston passes substantially rectilinearly through the piston in a direction parallel to the said predetermined direction, the cross-section of the passageway being small in relation to the area of the piston on which the extinguishant acts.

4. A fire extinguishing arrangement, comprising: a vessel storing extinguishant under pressure; a discharge mechanism connected to the vessel and which is releasable so as to allow extinguishant to exit from the vessel under pressure; at least one nozzle assembly; and pipe means connecting the nozzle assembly downstream of the discharge mechanism so as to receive extinguishant under pressure from the vessel through the discharge mechanism when the latter is released; the nozzle assembly comprising a cylinder having its interior connected to receive the extinguishant via the pipe means, a piston slidable in the cylinder, spring means biasing the piston into a rest position, the piston defining a face which is acted on by the extinguishant received in the cylinder so as to move the piston from the rest position, means defining a nozzle which is open to the outside environment, a passageway passing through the piston from and open to its said face and leading towards the nozzle, closure means acting between the passageway and the nozzle and movable between a closed position in which it closes the passageway off from the nozzle and an open position in which it connects the passageway to the nozzle, and means directly connecting the closure means to the said piston whereby movement of the piston from the rest position moves the closure means from the closed position to the open position, the closure means commencing to open the nozzle as soon as the piston starts to move from the rest position.

5. An arrangement according to claim 4, in which the said passageway has a cross-section which is substantially less than the cross-section of the said face.

6. An arrangement according to claim 4 or 5, including a first member defining an exit hole comprising the said nozzle, and in which the closure means comprises a second member and means mounting the two members for relative sliding movement in correspondence with movement of the piston from the said rest position.

7. An assembly according to claim 6, in which the said first member is a hollow sleeve mounted on the piston on the opposite side of the latter to the said face and open to the said passageway, the sleeve defining the said at least one exit hole and being a sliding fit within the second member which has an opening into juxtaposition with which the said at least one exit hole comes when the sleeve moves with the piston as the latter moves from its rest position.

8. An arrangement according to any one of claims 4 to 7, comprising at least one further said nozzle assembly and in which the said pipe means connects the said vessel to all of the nozzle assemblies downstream of the said discharge mechanism.

9. Afire extinguishing arrangement, substantially as described with reference to the accompanying drawing.