GB2171905A

GB2171905A - Explosion suppression arrangement

Info

Publication number: GB2171905A
Application number: GB08530533A
Authority: GB
Inventors: David Nicholas Ball; Simon John Davies
Original assignee: Graviner Ltd
Current assignee: Graviner Ltd
Priority date: 1985-03-06
Filing date: 1985-12-11
Publication date: 1986-09-10
Also published as: GB8530533D0; GB2171905B; GB2171904A

Abstract

Rods of propellant explosive are mounted parallel to each other to from a cased explosive charge 5, the casing 6 being substantially impervious. A hollow cutter assembly 20 carrying cutter blades 22 and 24 is normally held in the position illustrated. In the event of risk of explosion of the explosive charge 5, a diaphragm 34 is ruptured by an electrically detonatable explosive actuator 40. Explosion suppressant 32, stored under pressure in a container 18, advances rapidly through the ruptured diaphragm 34 and through the cutter assembly 20 and forces the latter rapidly downwards so that the blades 22 and 24 pierce the end of the impervious casing 6. The explosion suppressant can thus rapidly enter within the explosive charge 5. If the latter is in the form of individual rods of explosive arranged parallel to each other with their axial ends facing the cutter blades 22, 24, the dispersion process is aided by the air spaces between the rods. <IMAGE>

Description

1

SPECIFICATION

Explosion suppressant arrangements The invention relates to the suppression and 70 extinguishing off ires and explosions. In this specifica tion, references hereafterto suppression of explo sions are intended to include referencesto exting uishing of fires.

In certain circumstances, it is requiredto store 75 explosive substances in environments which may be potentially hazardous to such substances. Forexam ple, it may be required to store explosive substances in environments (such as within armoured vehicles) which are subjectto attack. Embodiments of the invention, to be described below, provide improved suppression of explosions in such substances.

According to the invention,there is provided an explosion suppression arrangementfor suppressing explosions in explosive charges, comprising support means supporting at least one of the explosive charges, cutter means mounted on the support means adjacentto the explosive charge and movable towards the explosive charge, storage means contain- ing an explosion suppressant under pressure, means for releasing the explosion suppressant, and guiding means for guiding the released explosion suppressant towards the explosive charge undertheforce of its said pressure, the cutter means being positioned so as to be forced into cutting engagementwith the explosive charge bythe released suppressant so as to allowthe explosive suppressantto enterthe explosive charge.

According to the invention, there is also provided an explosion suppression arrangementfor suppressing explosions in stored explosive charges, comprising a container storing the charges in predetermined positions, cutter means, means mounting the cutter means on a wall of the containerto be movable forwardly towards the explosive charges within the container and to cut a path through into each explosive charge, a store of explosion suppressant under pressure, releasable valve means for releasably confining the su ppressa nt within the store, meansfor opening the valve means wherebythe explosive suppressant emerges under pressure, means for directing the emerging suppressant into contact with the cutter means so as to drivethe cutter means forwardly so as to cutthe said path into the explosive charges, and guiding means for guiding the explosive suppressant into each explosive charge along the said path.

Explosion suppression arrangements embodying the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:

Figure 1 is a cross-section through part of one of the arrangements; Figure 2 is a diagrammatic view, partly in cross- section showing another of the arrangements; Figure 3 is a diagrammatic view of an ammunition round protected against inadvertent explosion by the arrangements shown in Figures 4 and 5; Figure 4 is a diagrammatic plan view showing a furtherone of the arrangements; and GB 2 171 905 A 1 Figure 5 is a diagrammatic view of yet anotherone of the arrangements.

In the arrangements nowto be described,the explosive substances being stored are propellant charges. One such charge is shown at 5 in Figure 1 and comprises a plurality of rod-like lengths of propellant explosive (indicated diagrammatically by way of example at 5A and 5B),these rods being stored with theiraxes vertical (as viewed in the Figure) and encased in an outer protective case 6. The case 6 may have a variety of differentforms. One such form which may be used resembles very stiff card which is substantially impervious.

Such a cased charge 5 may be stored inside an armoured vehicle such as a battle tank ready for use therein. The explosion suppression arrangement to be described isforthe purpose of suppressing inadvertent explosions of the material of the cased charge in the event, for example, of an attack by enemy ammunition.

As shown, the cased charge 5 is mounted within a cylindrical container 8 which has an upperflange 10. The flange 10 is bolted (by bolts not shown) to an intermediate flange 12 integral with the upper end of a cylindrical guide 14 and to a furtherflange 16which is integral with the lower end of an explosion-suppressant container 18. The guide 14 has slidably mounted within it a hollow cylindrical cutter assembly 20 which carries at i.s lower end a pair of semi circular cutter blades 22 and 24which are mounted at right angles to each other. The upper end of the cutter assembly 20 carries a collar 26. The cutter assembly 20 is held in the position illustrated bythin wire (not shown). The guide 14 has a shoulder30 on its inside.

The container 18 contains an explosion suppressant agent 32, which may be a liquid. This is stored within the container 18 under pressure. Exit of the suppressantfrom the container is prevented by a thin metal diaphragm 34which is held in position by bolts 36.

A hollow blocked off tube 38 extends into the extinguishant material 32. An electrically detonatable explosive actuator40 is located within the tube 38.

In operation, the actuator40 is detonated electrically in response to detectitn of a condition considered to be of danger to the cased charge 5. The resulting explosion within the tube 38 produces a shock wave which ruptures the diaphragm 34, and the suppressant 32 exits through the ruptured diaphragm under the force of the pressure within the container 18. The resulting pressure acts downwardly on the surface area of the blades 22 and 24. This causes the wire holding the cutter assembly 20 in the position illustrated to break and the cutter assembly is driven rapidly downwards until arrested by the collar 26 coming into contact with the shoulder 30. The blades 22 and 24thus pierce the casing 6 of the cased charge 5. This permits the suppressant agent 32 freelyto enter within the casing 6 where it is very rapidly dispersed around the rods of explosive, this process being aided bythe longitudinal air gaps between the rods.

Itwill thus be seen thatthe provision of the cutter blades 22 and 24 ensures thatthe suppressant is very rapidly brought into contactwith the actual explosive -even though the latter is housed within substantial- 2 GB 2 171 905 A 2 ly impervious material. It is essential thatthesuppres santagentbe brought into contactwiththe explosive material as rapidly as possible in orderto lower its temperature andto prevent explosion. Withoutthe provision of the cutter blades 22 and 24, this could not 70 take place.

In addition, the arrangement described is advan tageous because the cutter blades are driven into cutting engagementwith the case 6 bythe pressure of the emerging explosion suppressant and no separate 75 driving mechanism is therefore required.

ftwill be apparent thatthe arrangement described ensures thatthe integrity of the charge 5 is protected from contamination bythe suppressant (or by any thing else within the environment) by the casing 6 80 until actual suppression is activated.

The surface area which the blades 22 and 24 present to the emerging suppressant has to be sufficientto ensure thatthe cutter assembly 20 is propelled downwards with sufficientforce and speed. The 85 shape, orientation and/or number of the blades can be varied as appropriate.

It is clearly advantageous to ensure thatthe cutter assemb[y20 is oriented, in relation to the cased charge 6, to maximise the effect of the explosion suppressant. 90 In other words, the cutter assembly 20 should be positioned so as to move parallel to the axes of the explosive rods within the cased charge 6. In thisway, the longitudinal spacings between the rocisfacilitate the rapid distribution of the explosion suppressant.

It may be advantageousto arrangefor rotation to be imparted to the cutter assembly 20 as it is impelled towardsthe cased charge6, as by means of rifling.

Such rotation mayenhance the cutting effect of the blades 22 and 24.

The cutter assembly 20 need not be arranged to move vertically downwards. For example, it could move horizontally or vertically upwards and it is not necessary for itto move in a straight line. All that is required isforitto beableto move rapidly, underthe force produced bythe emerging explosion suppres sant, intocontactwith the appropriate partofthe casing 6.

Figure 2 shows, in simplified form, a modified arrangement in which parts corresponding to parts in Figure l are correspondingly referenced.

In the arrangement shown in Figure 2, there are six cased charges 5, each within its own case 6 corres ponding to the case 6 of Figure land each mounted vertically within its respective cylindrical container8, partofthewall of each of which is broken awayto showthe cased charge.

Each container 8 is connected to a respective suppressant supply pipe 50 by means of a respective flanged joint 52. Each supply pipe 50 is connected via 120 an extension 53 to a manifold 54which is in turn connected by a supply pipe 56to an explosion suppressant container 18 corresponding to the con tainer 18 of Figure 1, the container 18 holding an explosive suppressant agent under pressure. 125 As shown on the right hand side of Figure 2, each of the six suppressant supply pipes 50 holds a respective cylindrical guide 60 within which is slidably mounted a cutter assembly 20 corresponding to the cutter assembly 20 shown in Figure 1. Each cutter assembly 130 thus supports a pair of cutter blades 22 and 24. The cutter assemblies 20 maybe held in the position illustrated by means of thin wires (not visible).

As shown in the extreme right hand supply pipe 50, the extension pipes 53 are closed off from the respective supply pipes 50 by respective thin metal diaphragms 34 corresponding to the diaphragm 34in Figure 1. Immediately adjacent to each diaphragm 34 is a respective closed-off hollowtube corresponding tothetube38ofFig ure 1 and, like that tube, accommodating an electrically detonatable explosive actuator40.

In the arrangement shown in Figure 2, itwill be apparent thatthe explosion suppressant container 18 fills the supply pipe 56, the manifold 54, and each extension pipe 53 with suppressant under pressure, this pressure acting on the underside of each diaphragm 34.

When it is detected thata particular one of the cased charges 5 is under dangerof explosion,the appropriate one of the detonators 40 iselectrically actuated. The resultant pressure within the extension pipe 53 ruptures the adjacent diaphragm 34 and thesuppression agent advances rapidly, underthe pressure within the system, so asto propel the cutter assembly 20 vertically upwards at high speed. The cutter blades 22, 24therefore pierce the casing 6 of the cased charge in the mannerdescribed with referenceto Figure 1 and floodthe rods of explosivewith the suppression 95 agent.

In thisway, therefore, the arrangement shown in Figure 2 uses a single bottle of explosion suppression ageritto protect several (six in this case) cased charges, but allows the suppression ageritto be activated individually in relation to each of the cased charges.

The detonators 40 in both of the arrangements illustrated may be arranged to be activated in a variety of ways. They could, for example, be activated manually by an operator. instead, they could be operated automatically. Forexample, each case charge 5 could be partially or completely surrounded by an electrically energised grid or printed circuit board. If thiswere pierced, such as by an ammunition fragment, a resultant electrical signal would be produced which would detonatethe corresponding detonator40. InsteadJor example,the detonators 40 could be set off by activation of a fire or explosion detection system within thevehicle in which the cased charges are mounted.

The arrangements as so far described are for preventing orsuppressing inadvertent explosions of cased charges comprising rod-like lengths of propel lant explosive which are encased together in the coutercase6 (as shown in Figures 1 and2). Howeverit mayalso bedesirableto suppress inadvertent explosions in othertypes of stored explosive substances, in particular individual ammunition rounds orshells. which may be stored together in a suitable container. Figure 3 shows an example of such a round. This round comprises a casing or cartridge 100 storing the explosive charge 102 forthe round. A number of such rounds may be stored together, for example side-byside and vertically, within a case or enclosure, in a battle tankfor example. Clearly,the arrangements 3 GB 2 171 905 A 3 shown in Figures 1 and 2 cannot be used in the same manneras described in those Figures in orderto suppress inadvertent explosions in such stored rounds. Thus, if a case or enclosure containing a plurality of vertically arranged side-by-side rounds 1 00were placed within the cylindrical container 8 of the arrangement of Figure 1, instead of the cased charge 5,the cutter assembly 20 clearly could not operate to pierce the appropriate positions on the rounds to direct explosion suppressant to the explosive charges 102 in the rounds. In such a case, alternative arrangements have to be used and examples of such arrangements will now be described with reference to Figures 4 and 5.

Figure 4 shows one example of such an arrangement. Here, it is assumed thatthe rounds 100 are stored so as to stand vertically upwards (that is, with their pointed ends uppermost) in a box or enclosure 104 (which may have a lid which is omitted in the Figure). Items shown in Figure 4 corresponding to similar items in the arrangement of Figure 2 are similarly referenced exceptforthe addition of the suffix "A".

As shown in Fig u re 4, a respective su ppressant supply pipe 50A is provided for each of the four rounds 100. Each su pply pipe 50A is mounted on the side of the enclosure 104 by means of a respective flanged joint 52A so as to be positioned in line with a n opening through the side of the enclosure which is itself in line with the part of the round storing the explosive charge 102 (see Fig. 3). Each supply pipe 50A is thus connected via an extension 53Ato a manifold 54A which is in turn connected by a supply pipe 56Ato an explosion suppressant container 18A corresponding to the container 18 of Figure 1. The container 18A holds the explosive suppressant agent underpressure.

As with the arrangements shown in Figure 2, each of the supply pipes 50A holds a respective cylindrical guide 60A within which is sl idably mounted a cutter assembly 20A corresponding to the cutter assembly 20 shown in Figure 1. Each cutter assembly 20A thus supports a pair of cutter blades 22A, 24A. Not all the supply pipes 50A are broken away in Figure 4to reveal the mechanism inside.

One of the supply pipes in Figure 4 is broken awayto show how (similarlyto the Figure 2 arrangement), thepipes53A are closed off from the respective pipes 50A bythin metal diaphragms 34A. Immediately adjacentto each diaphragm 34A is a respective 115 closed-off hollowtube corresponding tothetube 38 of Figure 1 and, likethattube, accommodating an electrically detonatable explosive actuator40A.

The container 18Afillsthe supply pipe 56A,the manifolds 54A, and each pipe 53Awith suppressant under pressure,the suppressant being blockedfrom the pipes 5OAfrom the diaphragms 34A.

When it is detected that a particular one (or more than one) of the rounds 100 is under danger of explosion, the appropriate one orones of the cletonators40A is electrically actuated. The resultant pressurewithin the extension pipe or pipes 53A ruptures the appropriate diaphragm 34A. The suppressant agent propels the corresponding cutter assembly 20A at high speed towards the corresponding round 100 so 130 asto pierce the side of the round and floodthe explosive 102 with suppression agent.

If the enclosure 104 contains more than four rounds 100, additional pipes 50A would be provided each directed towards the appropriate position on one of these rounds. This may for example necessitate feeding one or more of these pipes through the wall of the enclosure 104 and between others of the rounds in orderto reach the specific round being protected.

Figure 5 shows another arrangement in which the rounds 100 are stored vertically upwards in a linear box orenclosure 106. In this arrangement, likethe arrangement of Figure 4, a respective suppressant supply pipe 50A is provided for each round 100, each pipe 50A being mounted on the side of the enclosure 106 so as to be in alignmentwith an aperture through the enclosure which is itself in alignmentwith the explosive charge 102 of the respective round.

Items in Figure 5 corresponding to those in Figure 4 are similarly referenced, and it is believed thatthe construction and operation of Figure 5 is clearfrom the description already given with referenceto Figure 4.

The detonators 40A in the arrangements illustrated in Figures 4and 5 may be arranged to be activated in a varietyof ways and, in particular, in any of theways described above with referenceto Figures 1 and 2. In relation to the use of the electrically energised grid or printed circuit board described above as partially or completely surrounding each cased charge 5 (in the arrangements of Figure 1 and 2) for detecting an attack and producing an electrical signal for detonating the corresponding cletonator40, such a grid or printed circuit board could be arranged around each indi- vidual round 100 in the arrangements of Figures 3 and 4 or, instead, around the whole enclosure 104 or 106.

In relation to all the embodiments described, itwill be appreciated thatthe explosion suppression agent need not be released by means of an explosive

Claims

actuator. Instead, other means of releasing the suppression agent could be used which may be appropriate to differenttypes of suppression agents, for example, fluidised powders stored under pressure. CLAIMS

1. An explosion suppression arrangement for suppressing explosions in explosive charges, comprising support means supporting at least one of the explosive charges, cutter means mounted on the support means aejacentto the explosive charge and movable towards the explosive charge, storage means containing an explosion suppressant under pressure, means for releasing the explosion suppressant, and guiding means for guiding the released explosion suppressanttowards the explosive charge underthe force of its said pressure, the cutter means being positioned so as to be forced into cutting engagement with the explosive charge bythe released suppressant so as to allow the explosive suppressantto enterthe explosive charge.

2. An arrangement according to claim 1, in which the cutter means is mounted for linear movement within the guide means and in which the releasing means comprises means immediately adjacent the cutter means for releasably blocking the explosion suppressant.

4

3. An arrangement according to claim 2, in which the releasing means comprises a rupturable di aphragm and meansfor rupturing the diaphragm.

4. An arrangement according to claim 3, in which the means for rupturing the diaphragm comprises electrically detonatable explosive means.

5. An arrangement according to any preceding claim, in which the explosive charge comprises a plurality of separate longitudinally extending rods of explosive which are mounted side-by-side with their 75 axes parallel and within a casing constituting the said support means, and in which the cutter means is mounte on the casing so as to be movable towards the axial ends of the rods wherebyto maximise the flow of explosion suppressant along longitudinally extending 80 spaces between the charges.

6. An arrangement according to claim 5, in which there area plurality of separate said casings in each of which is mounted a respective said plurality of separate longitudinally extending rods of explosive mounted sideby-side with their axes parallel, and in which there area plurality of said cutter means, one for each said casing.

7. An arrangement according to claim 6, in which there is a single said storage means.

8. An explosion suppression arrangementfor suppressing explosions in stored explosive charges, comprising a container storing the charges in prede termined positions, cutter means, means mounting the cuttermeans on a wall of the containerto be movable forwardly towards the explosive charges within the containerandto cut a path through into each explosive charge, a store of explosion suppres sant under pressure, releasable valve meansfor releasably confining the suppressantwithin the store, meansfor opening the valve means whereby the explosive suppressant emerges under pressure, means for directing the emerging suppressant into contactwiththe cutter means so asto drivethe cutter means forwardly so as to cutthe said path into the explosive charges, and guiding meansfor guiding the explosive suppressant into each explosive charge along the said path.

9. An arrangement according to claim 7, in which the explosive charges comprise a plurality of separate lengths of explosive mounted within the said contain erso thatthe said path consists of a path through a wall of the container.

10. An arrangement according to claim 9, in which the lengths of explosive are longitudinally extending rods of explosive mounted side-by-side with their axes parallel, and in which the said wall through which the cutter means cuts the said path is positioned to extend across the axial ends of the rods wherebyto maximise the flow of explosion suppressant along longitudinally extending spaces between the rods.

11. An arrangement according to claim 8 or9, in which each explosive charge comprises an individual ammunition round mounted in a predetermined position within the said container, and in which the cutter means is movable through thewall of the container and cuts the said path through a casing of the ammunition round itself.

12. An arrangement according to anyone of claims 8 to 11, in which the guide means comprises a GB 2 171 905 A 4 hollowtube along which the explosive suppressant advances when the valve means is opened and in which the cutter means comprises means carrying at least one cutter blade and confined for sliding movementwithin the tube.

13. An arrangement according to any one of claims 8 to 12, in which the valve means comprises rupturable diaphragm means and detonatable means for rupturing the diaphragm means.

14. An arrangement according to any preceding claim, including means for detecting a condition likely to causethe explosion of a said explosive charge, and means responsiveto detection of such condition for releasing the explosion suppressant.

15. An explosion suppression arrangement, substantially as described with reference to Figure 1 of the accompanying drawings.

16. An explosion suppression arrangement, substantially as described with reference to Figure 2 of the accompanying drawings.

17. An explosion suppression arrangement, substantial ly as described with reference to Figures 3 and 4of the accompanying drawings.

18. An explosion suppression arrangement, sub- stantially as described with reference to Figures 3 and 5 of the accompanying drawings.

Printed in the United Kingdom for Her Majesty's Stationery Office, 8S18935, 9186 18996. Published at the Patent Office, 25 Southampton Buildings, London WC2A lAY, from which copies may be obtained.