GB2525211A - Improvements in fire suppression devices and systems - Google Patents

Abstract

A fire suppression device comprises a tank 2 for containing a fire suppressing fluid, said tank comprising at least one filling inlet 4 for filling the tank with fire suppressing fluid, at least one discharge outlet 12 for discharging the fire suppressing fluid from the tank to a surrounding environment. The fire suppression device further includes a submersible pump 6 within said tank comprising at least one pump inlet 8 configured to draw fire suppressing fluid from within the tank, and at least one pump outlet 7, fluidly connected to the at least one discharge outlet. The submersible pump is substantially housed within a sleeve 9, wherein the sleeve is secured to the base of the tank and incorporates at least one opening 10 in close proximity to the base of the tank for the passage of fire suppressing fluid to the pump inlet. In use, the at least one opening is configured to ensure that the pump draws fire suppressing fluid from the base of the tank thus preventing cavitation within the fire suppressing fluid. The discharge outlet preferably includes an isolation valve and a mist generating nozzle.

Description

Improvements in Fire Suppression Devices and Systems This invention pertains generally to the field of fire suppression devices and systems for extinguishing fires, and in particular fire suppression dcvices and systems that deploy a lire suppressing fluid in mist Form.

Fire suppression devices, such as fire extinguishers, are active fire protection devices for extinguishing fires. Typically, a fire extinguisher consists of a hand-held, cylindrical, pressurised tank containing a fire suppressing fluid which can be discharged through a nozzle to extinguish a fire. ffi some fire suppression devices, the lire suppressing Iluid is water that may he expelled by a pressurised gas or by way of a motive device. Water is advantageous in that it is inexpensive. hamless to surrounding persons and the environment and provides for a relatively easy clean-up after the fire has been extinguished.

Sonic fire extinguishers in existence discharge the water as a water mist, and incorporate a misting nozzle that breaks up a stream of water to generate the mist. A mist is a phenomenon that comprises small droplets of water that are suspended in air. These extinguishers typically use a dry water mist or super line spray that forms a mist curtain or plume when discharged. These extinguishers may use de-ionised water and are thought to provide a rapid, effective and clean means of fighting fires when compared to powder, foam and wet chemical extinguishers.

Typically, such fire suppression devices comprise a tank or reservoir of fire suppression lluid, and separate pumping means to draw fluid from the tank or reservoir and discharge the fluid through a network of pipes and discharge nozzles. Where possible, the pump is situated alongside the tank or reservoir, although due to space constraints this is not always possible, and therefore delivery means such as a pipe is required between the two. With the pump being a separate unit, there is an increased risk of mechanical failure due to air pockets. fluid kakage and device breakdown.

One possible solution is to submerge the pump within the tank.

although not typically found within extinguishing devices. Fluid tanks that incorporate submerged pumps as a means of delivery of said fluid can often suffer from issues with cavitation, or pockets of air and turbulence within the fluid. This is a common problem when a pump draws fluid from different regions within a tank of fluid. Cavitation often occurs when there is low pressure. turbulence or high suction, and reduces the efficiency of the pump whilst increasing wear and tear on the moving parts. Should the pump draw in a pocket of air, mechanical failure of the pump can also occur.

Existing fire tanks and fire suppression devices do not typically incorporate means of automatic filling, and topping up the tank under controlled means. These means of automatic filling allow for the fire suppression device to be used for as long as required, with the pump drawing fire suppression fluid from the tank, and the automatic filling means replacing the fire suppression fluid on an ongoing basis.

The prior art shows a number of devices which attempt to address these needs in various ways.

CM 202,005,969 (Xiubo et al) discloses an automatic fire extinguishing device comprising a water tank and a submersible pump mounted within the water tank. Whilst proposing the use of a submersible pump within the water tank of a fire extinguishing device, the disclosure does not propose any means ol dealing with cavitation and air pockets within the liquid, and the harmful effect of these air pockets and accompanying turbulence on the functioning of the pump. The tank does not appear to incorporate any means of automatically filling the tank with the fire suppression fluid, to allow for the fire suppression device to be used for as long as required until the fire has been suppressed.

CM 2,389,928 (Wang et al) discloses an immersible pump for firefighting purposes for use within buildings, whereby the pump is submerged within a waterjacket or water reservoir. A water outlet pipe ol the water jacket is connected with a water delivery pipe through a flange. and is connected with a water supply pipe through a one-a valve.

Whilst the prior art appears to address the problems associated with pump failure through submerging the pump within the tank, they do not appear to address the effects of cavitation of the liquid within the tank. They also tend to require frequent filling of the fire suppressing fluid, and do iiot incorporate means for automatic filling.

Preferred embodiments of the present invention aim to provide a fire suppression device with improved submersible pump fluid intake mems, that prevents cavitation from occurring within the reservoir of fire suppressing fluid.

In a further embodiment, die present invention aims to provide a fire suppression system. whereby the fire suppression device is configured to deliver fire suppression fluid in mist form to a plurality of locations.

According to one aspect of the present invention, there is provided a fire suppression device for suppressing a fire, the fire suppression device comprising: -a tank for containing a fire suppressing fluid said tank comprising at least one filling inlet for filling the tank with fire suppressing fluid, and at least one discharge outlet for discharging the fire suppressing fluid from the tank to a surrounding environment; and.

-a submersible pump mounted within said tank comprising at least one pump inlet configured to draw fire suppressing fluid from within the tank, and at least one pump outlet, fluidly connected to the at least one discharge outlet, whereby the submersible pump is suhstantialy housed within a sleeve, the sleeve being secured to the base of the tank and incorporating at least one opening in close proximity to the base of the tank for the passage of fire suppressing fluid to the pump inlet, whereby, in use, said at least one opening is configured to ensure that the pump draws lire suppressing fluid from die base of the tank thus preventing cavitation within the fire suppressing fluid.

Preferably, the submersible pump comprises a multi-stage centrifugal pump mounted in a vertical condition within the tank.

Preferably, the submersible pump is electrically driven.

The sleeve may be secured to the base of the tank.

Preferably, the at least one discharge oudet incorporates an isolating valve.

The at least one discharge outlet may comprise at least one mist generating means configured to convert the fire suppression fluid into a mist.

The mist generating means may comprise at least one discharge nozzle.

The fire suppression device may comprise a test valve, said test valve being in fluid communication with the at least one pump outlet, and providing means to return the fire suppressing fluid to the tank when the fire suppression device is configured in test mode.

The filling inlet may comprise an inlet valve.

The filling inlet may comprise a balicock configured to control the filling ol the tank.

Preferably, the filling inlet comprises at least one overflow outlet for preventing the tank from overflowing.

The fire suppression device may comprise at least one bracket for reasonably securing the fire suppression device to a support structure.

Preferably. the fire suppressing fluid is water.

The tank may incorporate a removable top cover.

The submersible pump may he operatively connected to a control panel for controlling said submersible pump.

A fire suppression system incorporating at least one fire suppression device as hereinbefore described, whereby the at least. one fire suppression device is fluidly connected to a plurality of discharge nozzles.

For a better understanding of the invention and to show how embodiments of the same may he carried into ellect, relerenee will now he made.

by way of example, to the accompanying diagrammatic drawings. in which: Figure 1 shows one embodiment of a fire suppression device in section view, showing a submersible pump contained within the tank and housed within a sleeve; Figure 2 shows the lire suppression device of Figure 1 showing one embodiment of test mode for testing the fire suppression device; Figure 3 shows a further embodiment of fire suppression device in section view, incorporating filling control means; Figure 4 shows yet a lurther embodiment of fire suppression device in section view, showing a plurality of brackets for mounting said device to a support structure; Figure 5 shows the lire suppression device of Figure 4 in side view, and Figures SA. SB and SC show cross-sections through the fire suppression device showing the different configurations of brackets; Figure 6 shows the lire suppression device of Figures 2 and 3.

showing the tank with a removable cover; and.

Figure 7 shows one embodiment of fire suppressing system showing the fire suppressant device of Figure 6 when fluidly connected to a plurality of discharge nozzles.

In the ligures like references denote like or corresponditig parts.

Figure 1 shows a fire suppressing device 1 comprising a tank 2 for filling with a Iirc supprcssing fluid 3. Thc tank 2 compriscs at lcast onc filling inlet 4 for filling the tank 2 with the fire suppressing fluid 3. The filling inlet 4 may incorporate an inlet float valve 5 that allows the filling of the fire suppressing fluid 3 through the filling inlet 4 to he controlled. The filling ifflet 4 may he configured to be pcrnianently connected to a source of fire suppressing fluid 3, or a live fluid supply, through a hose or similar, such that the tank 2 may be automatically filled and any fire suppressing fluid 3 drawn from the tank 2 automatically replaced.

A submersible pump 6 is secured within the tank, such that the submersible pump 6 is submerged within the fire suppressing fluid 3 contained therein. The submersible pump 6 comprises a vertica' pump that is electrically controlled. The control of the submersible pump 6 may be through a control interface, not shown. The submersible pump 6 incorporates at least one pump outlet 7 and at least one pump inlet 8. The pump inlet 8 draws fire suppressing fluid 3 from the base of the tank 2. and pumps this fire suppressing fluid under pressure through the pump outlet 7.

The submersible pump 6 may incorporate a hermetically sealed motor that is close-coupled to the submersible pump 6 body. This whole assembly is submerged within the fire suppressing fluid 3. Submersible pumps 6 are typicafly designed to deal with some of the effects of pump cavitation, by removing the height difference between the pump and the fluid surface.

Submersible pump 6 pump fire suppressing fluid 3 to the surface. The submersible pump 6 Ihat Forms part of the firc suppressing device 1 is operativdy connected to a power supply means, not shown. The submersible pump 6 is mounted within the tank 2 in a substantially vertical configuration The submersible pump 6 is housed within a sleeve 9. The sleeve 9 contains a plurality of sleeve openings 10. The sleeve 9 is permanently secured to the base of (lie tank 2 through welding or similar means. The sleeve 9 may also be permanently secured to the top of the tank 2, and therefore secured to the tank 2 both at the top and at the bottom. The plurality of sleeve openings 10 are located towards the base of the tank 2, such that the fire suppressing fluid 3 is drawn from the base of the tank 2 through the sleeve 9 and into the pump inlet 8. By drawing the fire suppressing fluid 3 from the base of the tank 2, cavitation of the fire suppressing fluid 3 is prevented, and therefore air bubbles and turbulence within the fire suppressing fluid is minimised.

The sleeve 9 ensures that the submersible pump 6 draws in fire suppressing fluid 3 from the bottom of the tank 2. This ensures that the submersible pump 6 can draw in the full volume of fire suppressing fluid 3 contained within the tank 2. The pump inlet 8 has to be configured a distance above the base of the tank 2, and the sleeve 9 ensures that the volume of fire suppressing fluid 3 contained within the tank 2 beneath the height of the pump inlet S can be drawn in and pumped. This allows br a smaller tank 2 to he used.

since the majority of the fire suppressing fluid 3 contained therein is being made use of.

The pump outlet 7 is fluidly connected to a discharge outlet 12, through which the pumped fire suppressing fluid 3 is discharged. The discharge outlet 12 is fluidly connected to at least one discharge nozzle to make up a fire suppressing system, said discharge nozzle converting the fire suppressing fluid 3 to a mist form. The discharge outlet 12 may incorporate an isolating valve 11 to stop the flow oithe fire suppressing fluid 3 through the discharge ouUet 12.

Figure 2 shows the lire suppressing device 1 in test mode, where the fire suppressing device 1 incorporates means to test the device to ensure that the submersible pump 6 is operating correctly and efficiently. The test mode comprises a test valve 13 in fluid communication with the pump ouflet 7, whereby the fire suppressing fluid 3 follows an alternative path to that of the discharge outlet 12. k test mode the isolating valve 11 is closed, and the fire suppressing fluid 3 redirected through a test valve 13 and hack through a return inlet 14 in the wall of the tank 2. This ensures that in test mode the fire suppressing fluid 3 is not wasted, but is fed back into the tank 2.

Therefore, when in test mode, the fire suppressing fluid 3 is isolated from the discharge outlet 12 by closing the isolating valve 11. and the test valve 13 is opened to allow the fire suppressing fluid 3 to be pumped along this alternative path. thus testing the function of the submersible pump 6. Under normal operating conditions, however, the test valve 13 is closed, and the isolating valve is open, thus ensuring that the fire suppressing fluid 3 is pumped to the discharge outlet 12.

Figure 3 shows one embodiment of means of controlling the filling of the tank 2, and preventing overflow of the tank 2. This means of controlling the filling of the tank 2 at the filling inlet 4 is controlled through a ballcock, which comprises the inlet float valve 5 in mechanical communication with a float 15.

The foal 15 and inlet float valve 5, help to control the maximum level of lire suppressing fluid 3 within the tank 2. The hallcock prevents overfilling of the tank 2 by isolating the inflow of fire suppressing fluid 3 once a predetermined level has been reached. Any excess fire suppressing fluid 3 diverts through an overflow outlet 16 in the tank 2. Should the float 15 or inlet float valve fail, the overflow fire suppressing fluid 3 would he diverted through the overflow oufiet 16.

Figure 4 shows a plurality of brackets 17 about the periphery of the exterior of the tank 2. These brackets 17 allow the tank 2 to be mounted to a support structure. The brackets 17 are also designed to leave a small gap between the tank 2 and any support structure, thus preventing condensation from forming where the tank 2 would typically come into contact with the support structure.

These brackets 17 can also be seen in Figure 5. where the brackets 17 are about the entire periphery of the tank 2. These brackets 17 may only be about a portion of the periphery of the tank 2 not shown. The tank 2 may comprise one bracket 17, or any other number of brackets 17 as required to support the specific size and construction of tank 2. The brackets 17 are also configured to prevent bowing of the tank 2 under the weight of the fire suppression fluid 3 contained therein.

These brackets 17 may be situated around the midway point between the top and the bottom of the tank 2.

Figure 6 demonstrates a removable cover 18 to the tank 2 to allow access to the interior of the tank 2 for maintenance purposes. The tank 2 is also provided with an AB air gap device 19. The removable cover 18 and AB air gap device 19 are designed to ensure that the unit complies with UK water supply regulations. This physical air gap 19 protects the incoming mains water supply, or where the fire suppressing fluid 3 comprises water from the mains supply. The AB air gap device 19 comprises a slot configured within the tank 2. provided with a partial cover and screened mesh, not shown.

The fire suppressing device 1 is configured to form part of a fire suppressing system. as shown in Figure 7. The submersible pump 6 discharges through pipework that is connected to the discharge outlet 12 when the isolating valve 11 is in an open position. The pipework transports the pumped fire suppressing fluid 3 to a pura1ity of discharge nozzles 20, said discharge nozzles incorporating means to convert the fire suppressing fluid 3 to a mist form, and discharging this mist into the surrounding environment. The fire suppressing fluid 3 may comprise water, and this water may he deionised, potalie or otherwise.

The fire suppressing device 1 may incorporate a control panel not shown. The control pand contrds thc suhmcrsihlc pump 6. The control pand may receive a signal from either an alairn detection device such as a smoke alarm, or a manual control. As soon as the control panel receives a signal that the fire suppression device I is required to he used, the control panel will activate the submersible pump 6. The control panel niay control the electrically-controlled submersible pump 6 by applying a voltage. This voltage will be single or three phase depending on whether a single or a three phase pump is used.

The tank 2 of the fire suppression device 1 will likely be manufactured from typical fire tank materials, such as stainless steel. However, the tank 2 may also be made from a polymer material or carbon fibre. The submersible pump will typically comprise stainless steel.

The tank 2 and submersible pump 6 can be available in a wide variety ol sizes depending on the site ol the building or area that the lire suppressing device 1 is designed to be deployed. The tank 2 is configured to be of a sufficient size to maintain a minimum of ten minutes discharge of fire suppressing fluid 3 under normal operating conditions, and depending of course on the number of discharge nozzles being used. The submersible pump 6 will also be configured to pump a sufficient volume of fire suppressing fluid 3 according to the various circumstances.

Further embodiments may include a range of different output pressures provided by the submersiHe pump 6. The discharge nozi]es 20 and other possible devices connected to the discharge outlet 12 are likely to require a different range of output pressure. The discharge nozzles 20 that are configured to generate a mist from die fire suppressing fluid 3, typically provide different sizes of mist droplets according to the pressure of the fire suppressing fluid 3 being pumped into it. These different droplet sizes provide different firefighting attributes. For an example, liquid based lires, or Class B fires, are hes tackled with smaller droplets, whereas larger droplets are more suitable for tackling solid fuel fires, or Class A fires The fire suppression device 1 may incorporate a pressure gauge, not shown, to indicate output pressure of the suhmersihle pump 6, and to allow the submersible pump 6 to be controlled through the control interface to alter this output pressure as required. The fire suppression device 1 may also incorporate a pressure switch, not shown in (lie drawings, that provides a remote signal in (lie event of operation.

The fire suppression device I may comprise an immersible pump instead of a submersible pump 6, that would sit on the bottom of the tank 2. and be configured to operate by much the same means as that previously described for a submersible pump 6. The submersible pump 6 is shown as being in a vertical configuration, hut the submersible pump 6 may also he mounted in a horizontal configuration

Claims (17)

1. CLAIMSI. A fire suppression device for suppressing a fire, the fire suppression device comprising: -a tank For containing a fire suppressing fluid said tank comprising at least one filling inlet for filling the tank with fire suppressing fluid, and at least one discharge outlet, for discharging the fire suppressing fluid from the tank; and, -a submersible punip mounted within said tank comprising at least one pump inlet configured to draw fire suppressing fluid from within the tank, and at least one pump outlet, fluidly connected to the at east one discharge outlet, whereby the submersible pump is substantially housed within a sleeve, the sleeve being secured to the base of the tank and incorporating at least one opening in close proximity to the base of the tank for the passage of fire suppressing fluid to the pump inlet, whereby, in use, said at least one opening is configured to ensure that the pump draws fire suppressing fluid from the base of the tank thus preventing cavitation within the lire suppressing fluid.
2. 2. A fire suppression device according to claim 1, wherein the submersible pump comprises a multi-stage centrifugal pump mounted in a vertical condition within the tank.
3. 3. A fire suppression device according to claims 1 or 2, wherein the submersible pump is electrically driven.
4. 4. A fire suppression device according to claims I to 3, wherein the sleeve is welded to the base of the tank.
5. 5. A fire suppression device according to any one of the preceding claims, wherein the at least one discharge outlet incorporates an isolating valve.
6. 6. A fire suppression device according to any one of the preceding claims, wherein the at least one discharge outlet comprises at least one mist generating means configured to convert the fire suppression fluid into a mist.
7. 7. A fire suppression device according to claim 6, wherein the mist generating me2ms comprises at least one discharge nozzle.
8. 8. A fire suppression device according to any one of the preceding claims, wherein fire suppression device comprises a test valve, said test valve being in fluid communication with the at least one punip outlet, and providing means to return the fire suppressing fluid to the tank when the Fire suppression device is configured in test mode.
9. 9. A fire suppression device according to any one of the preceding claims.wherein the filling inlet comprises an inlet valve.
10. 10. A fire suppression device according to claim 9, wherein the filling inlet comprises a hallcock conligured to control the filling ol the tank.
11. 11. A fire suppression device according to claims 9 or 10, wherein the fifing inlet comprises at least one overflow outlet for preventing the tank from overflowing.
12. 12. A fire suppression device according to any one of the preceding claims, wherein the fire suppression device comprises at least one bracket for reasonably securing the fire suppression device to a support structure.
13. 13. A lire suppression device according to any one of the preceding claims, wherein the fire suppressing fluid is water.
14. 14. A fire suppression device according to any one of the preceding claims, wherein the tank incorporates a removable top cover.
15. 15. A fire suppression device according to any one of the preceding claims, wherein the submersible pump is operatively connected to a control panel for controlling said submersible pump.
16. 16. A fire suppression device substantially as described herein with reference to the accompanying drawings.
17. 17. A fire suppression system incorporating at least one fire suppression device according to any one of the preceding claims, whereby the at least one fire suppression device is fluidly connected to a plurality of discharge nozzles.