WO2002068060A1

WO2002068060A1 - Fire suppression apparatus

Info

Publication number: WO2002068060A1
Application number: PCT/GB2002/000828
Authority: WO
Inventors: Tim Denne
Original assignee: Tomorrow's Design Company Ltd
Priority date: 2001-02-23
Filing date: 2002-02-25
Publication date: 2002-09-06
Also published as: GB0104578D0; WO2002068060A8

Abstract

Fire suppression apparatus comprising a housing arranged to contain a volume of fire suppression fluid, means within the housing for increasing the internal pressure within the housing, automatic trigger means arranged to operate the pressure increasing means in response to an electrical trigger signal, and one or more nozzles for producing an atomised mist of the fire suppression fluid upon increase of pressure beyond a predetermined threshold, the one or more nozzles being separated from the interior of the housing by a frangible seal which seals a passageway connecting the interior of the housing with the one or more nozzles.

Description

FIRE SUPPRESSION APPARATUS

The present invention relates to fire suppression apparatus.

Fire suppression apparatus comes in many forms with the most common being a sprinkler system. It is accepted that a sprinkler system is not appropriate for many premises or other locations where one wishes to suppress a fire due to the fact that it is a fixed installation. Fire suppression apparatus for suppressing fires in more restricted areas have been proposed but many still require specialist installation of water supplies or pressurised gas supplies in order to function. Manually operable extinguishers are, of course, known but the fact that they are manually operable is an inherent disadvantage.

As a result, there still exists the requirement for an automatic fire suppression apparatus which can be installed at a desired location without requiring any specialist plumbing and/or wiring. The present invention provides fire suppression apparatus comprising a housing arranged to contain a volume of suitable fire suppression fluid, means within the housing for increasing the internal pressure within the housing, automatic trigger means arranged to operate the pressure increasing means in response to an electrical trigger signal, and one or more nozzles for producing an atomised mist of fire suppression fluid upon increase of pressure beyond a predetermined threshold, the one or more nozzles being separated from the interior of the housing by a frangible seal provided in a passageway connecting the interior of the housing with the at least one nozzle. Preferably, the passageway is in the form of a tube one end of which is located near the bottom of the housing. The fire suppression fluid is usually water and the pressure increasing means is preferably a gas generation means immersed in the water. The advantage of this is that when the gas generation means is a pyrotechnic gas generator, the gases are automatically cooled by passage through the water. This arrangement also avoids the need to have a piston arrangement in the housing which is acted upon by the gas and used to expel the fire suppression fluid.

The electrical signal utilised to trigger the gas generation means is , preferably provided by a smoke and/or fire detector which is physically attached to the spherical housing. Preferably, the signal generated by the smoke and/or fire detector is inductively coupled to the gas generation means in order to ensure the structural integrity of the generally spherical container. The detector is provided with a power supply e.g. a battery and can be readily detached from the housing. In this way, when the detector is detached, the apparatus is safe to be handled as there is no power available to trigger the pressure increasing means. This feature can be enhanced by tuning the inductive circuit to filter out stray potential triggering sources.

The above arrangement is capable of discharging three litres of dense water fog in just 15 seconds at pressures of no more than 10 atmospheres. As a consequence, the housing can be made of plastics material so that the total weight of the apparatus is of the order of 3.5Kg. Such a device can protect a volume of about 100 cubic metres.

In order that the present invention be more readily understood, embodiments thereof will now be described with reference to the accompanying drawings in which: -

Fig 1 shows a perspective exploded view of fire suppression apparatus according to the present invention;

Fig 2 shows a cross-section through a preferred form of a part of the apparatus shown in Fig 1 ;

Fig 3 shows a detail of an alternative form of a part of the arrangement shown in Fig 2. The preferred embodiment of the present invention which will be described in more detail later is made from plastics, entirely self-contained, maybe no bigger than a football and weighs of the order of 3.5Kg. It is designed to be installed by a home owner in a few minutes with nothing more than a drill and a screw driver in just the same way as one might put up a shelf. It has no pumps, no plumbing and no stored pressure containers and is powered by a standard battery.

Turning now to Fig 1, this shows an overall view of one form of the preferred embodiment of the present invention. The apparatus comprises a generally spherical container 10 which is shown to have a waisted portion 11 in order to mount the spherical container in a retaining hoop 12 which is provided with fixing holes 13 to enable the container 10 to be mounted to a wall at a suitable location, eg near the ceiling. Near the bottom of the container 10 there are provided one or more nozzles, and in this case, three are shown although there may be more, which are normally covered by a pop-off cover 16 when the apparatus is not in use. The nozzles 15 are designed to produce water droplets of approximately 50 microns in size during operation. Suitable, nozzles are available which are capable of producing an appropriately sized droplet under pressures of the order of 10 atmospheres (140-150psi).

The container is shown as having a part-spherical cover 20 but this is merely diagrammatic as will be apparent from the description of later drawings. The intention is that the cover 20 will enable the container to be filled with a measured amount of fire suppressant agent eg water and then sealed. The sealing is somewhat important as the container 10 and cover 20 are both designed to be of plastics material and have to be capable of withstanding the internal pressures mentioned above.

Attached to the container, and in this case to the cover 20, is a battery powered detector device 30 which is arranged to be removably connected to the container in any convenient manner eg by studs 31 which project from the cover 20 and are received in mating keyhole slots 32 in the bottom of the detector 30.

As will be described in more detail later in relation to Fig 2, the detector 30 is arranged to generate an electrical signal when it detects smoke and/or a fire and cause a pyrotechnic charge located within the container 10 and immersed in the fire suppressant agent to pressurise the container by generating gas within it. The communication of the electrical signal from the detector 30 to the pyrotechnic charge can be carried out in any convenient manner but at present we propose to utilise an inductive coupling between the detector 30 and a coil (not shown) located on the interior surface of the cover 20. The coil is conductively connected to the pyrotechnic charge and causes the charge to be ignited when an appropriate signal is present. The coil is provided with a tuning circuit for suppressing interference in order to ensure that the pyrotechnic charge circuit be triggered by incident. In operation, when a fire or insipient fire is detected by the detector 30, the pyrotechnic charge (Fig 2) is operated and the interior of the container 10 is pressurised to approximately 10 atmospheres. This in turn causes the nozzles 15 to eject fluid but, as will be explained later, before this happens the pop-off cover 16 has been automatically discharged from the container 10. The nozzles 15 are located to point downwardly at a general angle of 45° below the horizontal and to be clustered together so as to direct the droplets away from the wall to which the apparatus is mounted. In this way, three litres of water can protect a volume of about 100 cubic metres.

Further details of the construction and modifications thereto will now be described firstly in relation to the Fig 2 which shows a cross-sectional view of the container 10. In this arrangement, the container 10 is made of two approximately hemispherical members 10a and 10b which are arranged to be joined together around the equator of the sphere 10 in some convenient manner eg by spin welding. The upper part spherical member 10a is provided with the pyrotechnic gas generator 40 while the lower part spherical member 10b is provided with the nozzles 15 covered by the pop-off cover 16. As Fig 2 clearly shows, the nozzles are mounted in a recess formed in the otherwise part spherical wall of the portion 10b and in this present embodiment they are mounted in a flat wall portion 25 and project through holes in the flat wall 25. On the other side of the flat wall section 25 a siphon tube assembly 26 is fixed to the fiat wall 25. The assembly 26 is provided with an inlet 27 which is normally covered by a frangible membrane 28 so that in normal conditions, ie when not operating, the interior of the siphon assembly 26 is filled with air at atmospheric pressure due to the fact that it communicates with the external atmosphere through the nozzles 15. The frangible membrane 28 also has the effect of sealing the contents of the container 10 from the ambient atmosphere so that harmful contaminants such as bacteria cannot enter the container 10. h operation, when the pyrotechnic charge 40 is ignited and the interior of the container 10 pressurised by gas being generated and bubbling through the water to collect in a small free space at the top of the container, first of all the frangible membrane 28 is ruptured and water is forced under pressure into the internal passageway of the siphon tube assembly 26. The membrane is arranged to rupture at a predetermined threshold that ensures sufficient pressure has been built up in the container 10 in order for the nozzles to operate properly. This in turn causes the air within the siphon tube assembly to become pressurised which causes pressurised air to be ejected from the nozzles 15 to cause the cover 16 to be popped off. This is immediately followed by water droplets being emitted from the nozzles 15. The advantage of this form of construction of siphon tube and nozzles is that the structural integrity of the container 10 can be ensured since only relatively small holes need to be formed in the planar wall 25. However, it does mean that the siphon tube has to be fixed to the wall 25 prior to the two parts 10a and 10b being fixed together. This is not a considerable problem in view of the fact that it is also necessary to fix the pyrotechnic charge in position prior to assembly.

An alternative arrangement for the siphon tube and nozzle construction is shown in Fig 3 where again the nozzle or nozzles 15 are provided in a recess in the general spherical outline of the part 10b of the container. In this case, however, the wall of the recess is not totally flat and is shaped as represented by the sinuous wall 31 which forms an aperture 32 of relatively large diameter which is arranged to receive one end of a siphon tube assembly 33. The siphon tube assembly has a rear surface 34 and a front, nozzle supporting wall 35. The rear wall 34 is shaped to mate with the wall portion 31 of the recess and the arrangement is such that the siphon tube with nozzles can be fitted into the wall of the part spherical member 10b from the outside. In other words, the container 10 can be produced by assembling the parts 10a and 10b together prior to insertion of the siphon tube assembly 33 in to the aperture 32. Care needs to be taken to seal the siphon tube assembly 33 into the aperture 32. Once more, the inlet to the siphon tube is covered by a frangible membrane 28 and a pop off cover (not shown) is also provided.

As mentioned above, the pyrotechnic charge 40 is fired by a signal which is supplied from the detector unit 30 which is not shown in Figs 2 and 3. However, the internal coil 41 and conductive tracks 42 are shown. The exact location of the pyrotechnic charge can be altered from that shown in Fig 2 where it is shown to be on "12 o'clock". A filler plug 45 is provided in order to allow the container 10 to be filled after assembly. The plug 45 needs to be a pressure seal to avoid being discharged when the charge 40 is fired. To permit the container to be filled by a user, the plug

45 is proposed to be a screw-type plug with the container wall being provided with the internal or external screw threaded portion (not shown).

In addition to the above, the container can be fitted with a high pressure safety relief valve so as to be able to vent gas generated by the pyrotechnic charge 40 in the event of a malfunction or blockage as might occur if the fire suppressant fluid became solid due to extremely low temperatures. The pressure relief means could be a specific pressure relief valve or could be a specially weakened area of the container 10. In the latter case, the mounting of the gas generator could be designed to pop out of the container by a small amount in order to vent gas in an emergency. Additionally, while we have disclosed the use of water as the preferred form of fire suppressant fluid, this may be replaced by any suitable alternative depending upon the type of fire which it is wished to suppress. Alternatively or in addition, chemicals may be added to the basic fire suppression fluid in order to improve the performance of the fluid or for any other purpose.

Various other modifications may be made such as altering the joint between the two part spherical members 10a and 10b. In other words, they need not be substantially semi-spherical with the join line along the equator. The join line could be at any suitable location and need not pass through the centre of the spherical container.

Alternatively, the container 10 could be formed by blow moulding in order to create a largely unitary spherical container with the nozzle assembly, gas generator and internal conductive arrangement with the inductive coil being inserted through the aperture provided for blow moulding and/or through an additional aperture such as that shown in Fig. 3. In order to reduce cost and increase safety, the pyrotechnic charge 40 could be replaced by an alternative pressure increasing means such as an intumescent material or rapidly expanding foam or even a shape memory alloy.

Finally, although provision of the separable detector and inductive coupling are described in combination with the siphon tube and frangible seal arrangement, these features can be utilised independently of each other as can the alternative pressure increasing means.

Additionally, while the description has concentrated on the use of the apparatus as a fire suppression apparatus and for detecting smoke and/or fire, it is equally possible that the detector 30 could be a motion or other heat sensor and thus the apparatus have additional or separate functions as a security device in which case a marker dye could be added to the water and the device triggered on sensing of a fire or intrusion in to the volume covered by the device.

Claims

Claims:

1. Fire suppression apparatus comprising a housing arranged to contain a volume of fire suppression fluid, means within the housing for increasing the internal pressure within the housing, automatic trigger means arranged to operate the pressure increasing means in response to an electrical trigger signal, and one or more nozzles for producing an atomised mist of fire suppression fluid upon increase of pressure beyond a predetermined threshold, the one or more nozzles being separated from the interior of the housing by a frangible seal which seals a passageway connecting the interior of the housing with the one or more nozzles.

2. Apparatus according to claim 1, wherein the passageway extends from the one or more nozzles to a position near the bottom of the container.

3. Apparatus according to claim 2, wherein the passageway is in the form of a tube fixed to the interior of the housing in the region of the or each nozzle which each project through holes in the wall of the housing.

4. Apparatus according to claim 2 wherein the passageway forms part of a nozzle assembly which is inserted into the housing through an aperture.

5. Apparatus according to claim 1, wherein the housing is arranged to be provided with a detector unit for supplying an input signal to the automatic trigger means.

6. Apparatus according to claim 5, wherein the detector unit is battery operated.

7. Apparatus according to claims 5 or 6, wherein the detector unit is removable from the housing.

8. Apparatus according to claim 7, wherein the detector unit is provided with a coil and the housing is provided with a corresponding coil inductively coupled to the coil in the detector unit whereby to cause the pressure increasing means to operate.

9. Apparatus according to claim 8, wherein the housing coil is provided with filter means for suppressing interfering signals.

10. Fire suppression apparatus substantially as hereinbefore described with reference to the accompanying drawings.