GB2578666A

GB2578666A - Improvements in or relating to fire extinguishing equipment

Info

Publication number: GB2578666A
Application number: GB1912260.5A
Authority: GB
Inventors: Edwin Morris James; James Black Robert
Original assignee: LIFELINE FIRE & SAFETY SYSTEMS Ltd
Current assignee: LIFELINE FIRE & SAFETY SYSTEMS Ltd
Priority date: 2018-08-28
Filing date: 2019-08-27
Publication date: 2020-05-20
Anticipated expiration: 2039-08-27
Also published as: GB201912260D0; GB201813948D0; GB201900344D0; GB2578666B

Abstract

A dry chemical fire extinguisher (10) comprises a rigid pressure vessel (12) defining an interior space (26) and having an outlet (22), a flexible bladder (34) located within the interior space and having an interior (36) in fluid communication with the outlet. The extinguisher further comprises an outlet closure (24) having a conduit (28) and a valve (32) disposed within the conduit to selectively open and close the outlet. The flexible bladder is connected to pressure vessel in a gas tight manner in the vicinity of the outlet such that the interior space of the rigid pressure vessel surrounding the flexible bladder is not in fluid communication with the outlet. A quantity of a dry chemical is provided within the interior of the flexible bladder and propellant gas is provided both within the interior of the flexible bladder and within the interior space of the rigid pressure vessel surrounding the flexible bladder.

Description

Improvements in or Relating to Fire Extinguishing Equipment The present invention relates to fire extinguishing equipment, and in particular to a dry chemical powder fire extinguisher.

Fire extinguisher systems contained within vehicles, such as a competition vehicle or a defence vehicle, should ideally operate in any orientation. In the event that the vehicle becomes inverted or rolls onto its side, and operation of the fire extinguisher system is required, then the fire extinguisher system is required to deliver its contents efficiently no matter the orientation of the vehicle.

In many cases the on board fire extinguisher system of a vehicle use either a flexible pick up or dip tube, a bladder or piston to achieve this. These methods are ideal for discharging a fire suppressant or extinguishant that is either a liquid or gas.

One of the most efficient fire extinguishing agents is dry chemical powder, due to its efficiency in knocking down and extinguishing a fire, but its use has thus far been confined to hand held fire extinguishers where a predetermined upright orientation can be maintained.

When used in a system it can only be discharged using either a solid or semi flexible pick up, and the methods used to ensure the extinguisher operates in 360 degrees in any orientation as mentioned above do not work. A fully flexible dip tube will not penetrate the powder and sits on top of the medium therefore discharging a small quantity of dry powder and all of the super pressurising gas such as nitrogen A bladder filled with powder and pressurised around the outside of the bladder with a propellant gas to try and squeeze the power out will only crush the dry chemical and turn it in to a solid mass which will not discharge through the valve or delivery system.

A piston delivery system will only push the dry chemical in to a solid mass that cannot be discharged.

US 3,974,945 discloses an aerosol dispenser system for finely divided powder which utilises a liquefied neutral propellant which at least partially vapourises to deliver the finely divided powder.

According to a first aspect of the present invention there is provided a dry chemical powder fire extinguisher comprising a rigid pressure vessel defining an interior space having an outlet, a flexible bladder located within the interior space, said flexible bladder having an interior in fluid communication with the rigid pressure vessel outlet, the extinguisher further comprising an outlet closure having an outlet conduit and a valve associated with the outlet conduit to selectively open and close the outlet conduit and enable the interior of the flexible bladder to communicate with the exterior of the pressure vessel, wherein the flexible bladder is connected to the pressure vessel in a gas tight manner in the vicinity of the rigid pressure vessel outlet such that the interior space of the rigid pressure vessel surrounding the flexible bladder is prevented from being in fluid communication with the rigid pressure vessel outlet, wherein further a quantity of a dry chemical powder fire extinguishant is provided within the interior of the flexible bladder and a propellant gas is provided both within the interior of the flexible bladder and within the interior space of the rigid pressure vessel surrounding the flexible bladder, and wherein further a portion of outlet conduit extends into the interior of the flexible bladder In use, the opening of the valve associated with the outlet conduit permits the propellant gas contained within the flexible bladder to expand and exit the pressure vessel via the outlet conduit. The expanding gas fluidises and entrains the dry chemical powder fire extinguishant contained within the bladder and delivers the extinguishant through the conduit. The compression of the flexible bladder by the gas within the pressure vessel surrounding the bladder further assists with the delivery of the dry chemical fire extinguishant through the conduit.

The propellant gas may be an inert gas, for example Nitrogen. In on embodiment of the present invention the propellant gas provided within the interior of the flexible bladder is different from the propellant gas provided within the interior space of the rigid pressure vessel surrounding the flexible bladder. The propellant gas contained within the flexible bladder may optionally be a recognised fire extinguishant gas. In such an embodiment, both the propellant gas and the dry chemical powder may be utilised to extinguish a fire when delivered from the fire extinguisher.

The pressure vessel may be pressurised to approximately 10 Bar.

The portion of the outlet conduit that extends into the interior of the flexible bladder may comprise a perforated tube. The perforated tube seeks to prevent the possible occlusion, either wholly or partially, of the outlet conduit by the bladder during discharge of the extinguishant.

According to another aspect of the present invention there is provided a dual chamber dry chemical powder fire extinguisher comprising a rigid pressure vessel having a first chamber and a second chamber, each chamber of the pressure vessel defining an interior space having an outlet, a flexible bladder located within the interior space, said flexible bladder having an interior in fluid communication with the rigid pressure vessel outlet, each chamber of the extinguisher further comprising an outlet closure having an outlet conduit and a valve associated with the outlet conduit to selectively open and close the outlet conduit and enable the interior of the flexible bladder to communicate with the exterior of the pressure vessel, wherein each flexible bladder is connected to the pressure vessel in a gas tight manner in the vicinity of a respective rigid pressure vessel outlet such that the interior space of each chamber of the rigid pressure vessel surrounding a flexible bladder is prevented from being in fluid communication with the associated rigid pressure vessel outlet, wherein further a quantity of a dry chemical powder fire extinguishant is provided within the interior of each flexible bladder and a propellant gas is provided both within the interior of each flexible bladder and within the interior space of each chamber of the rigid pressure vessel surrounding each flexible bladder, and wherein further a portion of each outlet conduit extends into the interior of each flexible bladder.

Each chamber of the extinguisher is operable in the manner described above with reference to the first aspect of the invention. Each chamber may be associated with a different fire fighting location. With reference to a vehicle, one chamber may be associated with an engine space of the vehicle, which the other chamber may be associated with a passenger or driver space of the vehicle.

The outlets of the fire extinguisher may be provided at opposing ends of the rigid pressure vessel. The first and second chambers of the rigid pressure vessel may be separated by a common wall. The propellant gas may be an inert gas, and the propellant gas provided within the interior of each flexible bladder may different from the propellant gas provided within the interior space of each chamber of the rigid pressure vessel surrounding each flexible bladder. The chambers of each pressure vessel may be pressurised to approximately 10 Bar. The portion of each outlet conduit which extends into the interior space of each flexible bladder many comprise a tube which includes one or more perforations.

According to another aspect of the present invention there is provided a fire extinguishing system including a dry chemical fire extinguisher according to any of the preceding aspects. The system may include an actuator operable to open the valve. The system may further include a dry chemical distribution arrangement extending from the conduit. Such an arrangement may include a nozzle.

According to another aspect of the invention there is provided a vehicle including a fire extinguishing system according to the preceding aspect. The vehicle may be a wheeled vehicle or a tracked vehicle, an on-road vehicle or an off-road vehicle.

Embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a cross-sectional view of a dry powder fire extinguisher according to an embodiment of the present invention; Figure 2 shows a side view of a dry powder fire extinguisher according to another embodiment of the present invention; Figure 3 shows an end view of the extinguisher of figure 2; and Figure 4 shows the cross-sectional view indicated by arrows A-A in figure 3.

A first embodiment of the present invention will now be described with reference to Figure 1 which shows a cross sectional view of a dry powder fire extinguisher generally designated 10. The extinguisher 10 includes a generally bottle shaped rigid pressure vessel 12 having a base 14, side wall 16, shoulder 18 and neck 20. The bottle shape for the pressure vessel 12 is shown by way of a non-limiting example, and it will be understood that pressure vessel 12 may be provided in alternative configurations.

An outlet 22 of the pressure vessel 12 is provided in the neck 20 and is sealed by a closure 24. The base 14, side wall 16, shoulder 18 and neck of the pressure vessel 12, and the closure 24 define an interior space 26 of the pressure vessel 12. The closure 24 is provided with discharge or outlet conduit 28 which extends through the closure 24 from the interior space 26 to the exterior atmosphere 30 surrounding the extinguisher 10. The conduit 28 is provided with a valve 32 which is operable to open and close the conduit. The conduit 28 may connect to a nozzle or other fire extinguishant dispersion system (not shown).

Within the interior space 26 of the extinguisher there is provided a flexible bladder 34 having an interior 36. The bladder 34 may be formed from, for example, plastic, synthetic rubber or metal. The bladder 34 is connected to the neck 20 of the pressure vessel 12 in a gas tight manner. The interior 36 of the bladder 34 is thus in fluid communication with the discharge conduit 28 and, when the valve 32 is opened, the exterior atmosphere 30. The gas tight connection of the bladder 34 to the neck 20 of the pressure vessel 12 however prevents fluid communication between the portion of the pressure vessel interior space 26 surrounding the bladder 34 and the discharge conduit 28. While in the embodiment shown the bladder 34 is connected to the neck 20 of the pressure vessel 12 it will be understood that the bladder may be fitted to other portions of the pressure vessel in a gas tight manner. For example, the bladder may be connected in gas tight manner to a portion of the shoulder 18 which surrounds the neck 20.

In use, the interior 36 of the bladder 34 contains a quantity of a dry chemical. The dry chemical may comprise a dry powder fire extinguishant 38. The extinguishant may, for example, Monnex(RTM) dry powder. During manufacture or recharging of the extinguisher 10 after discharge, a measured quantity of dry powder fire extinguishant is introduced into the interior 36 of the bladder 34. The closure 24 is then fitted to the outlet 22 of the pressure vessel 12. The extinguisher 10 can then be pressurised by the introduction of a propellant gas into both the interior 36 of the bladder 34 and the pressure vessel interior space 26 surrounding the bladder 34. It will be understood that introduction of the propellant gas into the interior 36 of the bladder 34 may be achieved via the discharge conduit 28. Introduction of the propellant gas into the pressure vessel interior space 26 surrounding the bladder 34 may be achieved via a dedicated pressurisation port (not shown) of the pressure vessel 12.

The propellant gas may, for example, comprise an inert gas such as Nitrogen. In one embodiment the propellant gas provided within the bladder 34 may be the same as the gas surrounding the bladder 34. In alternative embodiment the propellant gas provided within the bladder 34 may be different to the propellant gas surrounding the bladder 34.

The extinguisher 10 may be pressurised to a pressure of, for example, 10 Bar. It will be appreciated that other pressures may be utilised. The pressure may depend upon such factors as the material characteristics of the dry powder extinguishant, the type of fire the extinguisher is intended to extinguish and such like.

In order to discharge the extinguisher 10, the valve 32 of the conduit 28 is opened. Opening of the valve 32 may be achieved in a number of ways including, but not limited to, manually via lever, toggle or pull cord, electrically via an electric actuator which is operated by a user or operates automatically due to a sensed condition.

Upon opening of the valve 32, the propellant gas provided within the interior 36 of the bladder 34 expands through the conduit 28 to the exterior atmosphere 30 surrounding the extinguisher 10. The expanding gas entrains the dry powder extinguishant 36 and moves the extinguishant 36 through the conduit 28 to the exterior atmosphere 30 surrounding the extinguisher 10. The delivery of the gas and dry powder 36 mixture though conduit 28 is assisted by expansion of the propellant gas provided within the pressure vessel interior space 26 surrounding the bladder 34. It will be understood that this gas does not escape the pressure vessel 12 but instead acts to compress the bladder 34.

The extinguisher 10 may be incorporated into a vehicle fire suppression system having an actuator operable to open the valve 32. The actuator may be of any known type suitable for use with a fire extinguisher including, for example, mechanical, electro-mechanical or electric. The actuator may be operated manually by a vehicle operator or passenger. The actuator may also be operable from the exterior of the vehicle, for example by a safety marshal. The actuator may also be operable automatically by a fire control system of the vehicle. The vehicle fire suppression system may include a distribution arrangement configured to deliver the extinguishant from the extinguisher 10 to a fire source, for example the engine bay of the vehicle. The vehicle may be a wheeled or tracked vehicle having on-road and/or off-road capabilities.

Referring now to figures 2 to 4 there is shown another embodiment of a dual chamber dry powder fire extinguisher generally designated 110. Features common to the embodiment described with reference to figure 1 prefixed with the numeral "1".

The extinguisher 110 includes a generally barrel shaped rigid pressure vessel 112 having a side wall 116 and shoulders 118 at opposing ends. An internal partition wall 140 divides the interior of the pressure vessel 112 into two interior spaces or chambers 126a, 126b. In the embodiment shown, the interior spaces 126a, 126b are each of a different volume. It will be appreciated that in an alternative embodiment, not shown, the interior spaces 126a, 126b may be of substantially equal volume.

Each shoulder 118 of the pressure vessel 112 surrounds an aperture which defines an outlet for each interior space 126a, 126b. Within each aperture there is provided a closure 124a, 124b. Each closure 124a, 124b is provided with discharge conduit 128a,128b which extends through the closure 124a, 124b from the respective interior space 126a, 126b to the exterior atmosphere 30 surrounding the extinguisher 110. Each conduit 128a, 128b is provided with a valve 132a, 132b which is mounted to the closure 124a, 124b.

Within each interior space 126a,126b of the extinguisher 118 there is provided a flexible bladder 134a, 134b having an interior 136a, 136b. The bladder 134a, 134b may be formed from, for example, plastic, synthetic rubber or metal. Each bladder 134a, 134b is connected to a respective closure 124a, 124b of the pressure vessel 112 in a gas tight manner. The interior 136a, 136b of each bladder 134a, 134b is thus in fluid communication with a discharge conduit 128a, 128b and, when the valve 132a,132b is opened, the exterior atmosphere 30. The gas tight connection of each bladder 134a, 134b to the respective closures 124a, 124b of the pressure vessel 112 however prevents fluid communication between the portion of the pressure vessel interior space 126a, 126b surrounding each bladder 134a, 134b and each discharge conduit 128a, 128b.

Each closure 124a, 128b is provided with a pressure gauge 142a, 142b which gives a visual indication as to the state of charge of each interior space 126a, 126b. Each closure 124a, 124b is further provided with a pair of connectors 144a, 144b which enable propellant gas to be introduced into (and removed from) the interior 136a, 136b of each bladder 134a, 134b, and the space surrounding each bladder 134a, 134b within the pressure vessel interior spaces 126a, 126b.

Each closure 124a, 124b is further provided with a perforated tube 146a, 146b forming part of the discharge conduit 128a,128b which extends into the interior of the bladder 134a, 134b. Each perforated tube 146a, 146b is mounted to the closure It will be understood that the purpose of the perforated tube 146a, 146b is to ensure that a portion or portions of the bladder 134a, 134b are not able to fully occlude the outlet conduit 128a, 128b during the discharge of propellant gas and dry powder from the bladder 134a, 134b.

In the embodiment shown and described with reference to figures 2 to 4, the extinguisher 110 has a dual chamber configuration. It will be appreciated that the described arrangement for the pressure vessel, closure, bladder and perforated tube may equally be utilised in a single chamber extinguisher of the type described with reference to figure 1.

The dual chamber extinguisher 110 may be utilised in instances where the extinguisher 110 is required to protect two separate spaces. With specific reference to a vehicle, the extinguisher 110 may be utilised to protect a machinery space of the vehicle (such as an engine space) and an occupant space of the vehicle (such as a driver and/or passenger space). Upon activation, the extinguisher 110 may be operated to deliver extinguishant from one or both chambers.

In the embodiments described with reference to figures 1 to 4, the interior space of the pressure vessel which surrounds the flexible bladder and the interior of the flexible bladder are both pressurised. In an alternative embodiment, the interior of the flexible bladder may be pressurised while the interior space of the pressure vessel surrounding the flexible bladder may remain unpressurised until operation or activation of the extinguisher. In such an embodiment, the extinguisher may be provided with a remote reservoir of pressurised gas which can be introduced into the interior space of the pressure vessel which surrounds the flexible bladder once the extinguisher is operated or activated.

Claims

Claims 1. A dry chemical powder fire extinguisher comprising a rigid pressure vessel defining an interior space having an outlet, a flexible bladder located within the interior space, said flexible bladder having an interior in fluid communication with the rigid pressure vessel outlet, the extinguisher further comprising an outlet closure having an outlet conduit and a valve associated with the outlet conduit to selectively open and close the outlet conduit and enable the interior of the flexible bladder to communicate with the exterior of the pressure vessel, wherein the flexible bladder is connected to the pressure vessel in a gas tight manner in the vicinity of the rigid pressure vessel outlet such that the interior space of the rigid pressure vessel surrounding the flexible bladder is prevented from being in fluid communication with the rigid pressure vessel outlet, wherein further a quantity of a dry chemical powder fire extinguishant is provided within the interior of the flexible bladder and a propellant gas is provided both within the interior of the flexible bladder and within the interior space of the rigid pressure vessel surrounding the flexible bladder, and wherein further a portion of the outlet conduit extends into the interior of the flexible bladder.
2. A dry chemical fire extinguisher as claimed in claim 1 wherein the propellant gas is an inert gas.
3. A dry chemical fire extinguisher as claimed in any preceding claim wherein the propellant gas provided within the interior of the flexible bladder is different from the propellant gas provided within the interior space of the rigid pressure vessel surrounding the flexible bladder.
4. A dry chemical fire extinguisher as claimed in any preceding claim wherein the pressure vessel is pressurised to approximately 10 Bar.
5. A dry chemical fire extinguisher as claimed in any preceding claim wherein the portion of the outlet conduit which extends into the interior space of the flexible bladder comprises a tube which includes one or more perforations.
6. A dual chamber dry chemical powder fire extinguisher comprising a rigid pressure vessel having a first chamber and a second chamber, each chamber of the pressure vessel defining an interior space having an outlet, a flexible bladder located within the interior space, said flexible bladder having an interior in fluid communication with the rigid pressure vessel outlet, each chamber of the extinguisher further comprising an outlet closure having an outlet conduit and a valve associated with the outlet conduit to selectively open and close the outlet conduit and enable the interior of the flexible bladder to communicate with the exterior of the pressure vessel, wherein each flexible bladder is connected to the pressure vessel in a gas tight manner in the vicinity of a respective rigid pressure vessel outlet such that the interior space of each chamber of the rigid pressure vessel surrounding a flexible bladder is prevented from being in fluid communication with the associated rigid pressure vessel outlet, wherein further a quantity of a dry chemical powder fire extinguishant is provided within the interior of each flexible bladder and a propellant gas is provided both within the interior of each flexible bladder and within the interior space of each chamber of the rigid pressure vessel surrounding each flexible bladder, and wherein further a portion of each outlet conduit extends into the interior of each flexible bladder.
7. A dual chamber dry chemical powder fire extinguisher as claimed in claim 6, wherein the outlets are provided at opposing ends of the rigid pressure vessel.
8. A dual chamber dry chemical powder fire extinguisher as claimed in claim 7 or claim 8 wherein the first and second chambers of the rigid pressure vessel are separated by a common wall.
9. A dual chamber dry chemical fire extinguisher as claimed in any of claims 6 to 8 wherein the propellant gas is an inert gas.
10. A dual chamber dry chemical fire extinguisher as claimed in any of claims 6 to 9 wherein the propellant gas provided within the interior of each flexible bladder is different from the propellant gas provided within the interior space of each chamber of the rigid pressure vessel surrounding each flexible bladder.
11. A dual chamber dry chemical fire extinguisher as claimed in any of claims 6 to 10 wherein the pressure vessel is pressurised to approximately 10 Bar.
12. A dual chamber dry chemical fire extinguisher as claimed in any of claims 6 to 11 wherein the portion of each outlet conduit which extends into the interior space of each flexible bladder comprises a tube which includes one or more perforations.
13. A fire extinguishing system including a dry chemical fire extinguisher as claimed in any preceding claim.
14. A fire extinguishing system as claimed in claim 13 wherein the system includes an actuator operable to open the or each valve.
15. A fire extinguishing system as claimed in claim 13 or claim 14 wherein system includes dry chemical powder distribution arrangement in fluid communication with each extinguisher outlet conduit.
16. A fire extinguishing system as claimed in claim 15 wherein the distribution arrangement includes a nozzle.
17. A fire extinguishing system as claimed in claim 16 wherein a pipe is provided between the extinguisher outlet and the nozzle.
18. A fire extinguishing system as claimed in claim 15 wherein the distribution arrangement includes a plurality of nozzles.
19. A vehicle including a fire extinguishing system as claimed in any of claims 13 to 18.
20. A vehicle as claimed in claim 19 wherein the vehicle is a wheeled vehicle or a tracked vehicle.
21. A vehicle as claimed in claim 19 or claim 20 wherein the vehicle is an on-road vehicle or an off-road vehicle.