SPRINKLER SYSTEM

Abstract: A sprinkler system has individual sprinkler devices (1) with respective alarm sensors (19-22), the sensors being connected to a common alarm (6). Actuation of any alarm sensor (19-22) triggers the alarm (4) and an indication is given as to the location of the actuated sensor (19-22). The sprinkler devices (1) are of the kind having a water outlet (12) blocked by a heat-fusible or heat-rupturable plug (15-17) with a cover plate (19) which normally conceals the outlet (12) and which drops away when the temperature rises to a predetermined level. The sensor (19-22) comprises an electrical circuit which is completed through the cover plate (19). The cover plate (19) is held in position by upstanding prongs (20) attached to the plate (19) by solder (20a) and plugged into sockets (21) on a moulded plastics housing (8) of the sprinkler device (1).

Description: SPRINKLER SYSTEM This invention relates to a sprinkler system. The use of fire sprinkler systems is an important safety measure taken to protect the occupants of both commercial and domestic buildings. In addition to controlling the spread of fire within the building, operation of sprinklers helps to reduce the heat and smoke generated by the fire to allow easier evacuation. Sprinkler systems of the type used in buildings to control the spread of fires conventionally comprise multiple water outlets connected to a main water supply, each outlet being closed with a fusible or heat-rupturable plug, whereby upon reaching a predetermined temperature the plug melts or breaks to allow water to escape from the outlet. There is a requirement for an alarm to be actuated to indicate that a sprinkler has operated and this can be achieved by applying a water flow sensor to the main supply which will pass a signal to the alarm as water flows to the open sprinkler outlet(s). This is not wholly satisfactory however, since it necessitates isolation of the main supply for the sprinkler outlets from the supply for other water outlets. The sprinkler system does not operate on 'fresh' water; it operates on water in a stagnant circuit or in a 'dry' system where flow of water is enabled by switching on of a pump and/or opening a valve after triggering of the alarm. This is not economically convenient, particularly in a domestic residence, as it involves the installation of additional, pipework and water-flow control equipment at considerable extra cost. Furthermore, conventional flow sensors can undesirably interfere with water flow to the sprinkler outlets and do not provide information as to which individual sprinkler or sprinklers has been actuated. An object of the present invention is to provide an alarm sensor that can be used in conjunction with a sprinkler system without the requirement for an isolated main water supply to the sprinkler system, and with which there is the possibility of providing helpful alarm information without interfering with the water flow. According to one aspect of the invention therefore there is provided a sprinkler device for a sprinkler system having a sprinkler outlet closed with a heat-fusible or heat-rupturable plug, a component which is adapted to move or change at a predetermined temperature to cooperate with sprinkler operation, and an alarm sensor arranged for actuation in correspondence with operation of the sprinkler outlet by heat fusion or rupture of the plug, characterised in that the alarm sensor comprises an electrical circuit having an electrical parameter determined by the said component whereby such parameter changes when the component moves or changes. With this arrangement, the alarm sensor is responsive to temperature at the individual sprinkler device; the alarm sensor can operate on a 'fresh' water system: isolation of the main water supply to the sprinkler system is not necessary and the sprinkler system can therefore be installed more economically. Also, since the alarm sensor can act independently of the water supply and individual sensor can be provided for each sprinkler device, water flow to the sprinkler devices is not restricted, and it is possible to arrange for helpful information to be obtained regarding the origin(s) of the alarm signal (e.g. which sprinkler device or devices have operated. Most preferably the said movable or changeable component comprises a cover plate beneath the outlet mounted relative thereto by a heat-sensitive connection which allows the cover plate to fall away to expose the outlet at a predetermined temperature. Thus, and in accordance with a second aspect of the invention there is provided a sprinkler device for a sprinkler system having a sprinkler outlet closed with a heat-fusible or heat-rupturable plug, a cover plate beneath the outlet mounted relative thereto by a heat-sensitive connection which allows the cover plate to fall away to expose the outlet at a predetermined temperature, and an alarm sensor arranged for actuation in correspondence with operation of the sprinkler outlet by heat fusion or rupture of the plug, characterised in that the alarm sensor comprises an electrical circuit having an electrical parameter defined by the cover plate whereby such parameter changes when the cover plate falls away. Preferably the sprinkler device has a deflector plate beneath the outlet to disperse water. Within each sprinkler device, the heat-fusible or heat-rupturabie plug may take any suitable form, but preferably incorporates a fine glass tube containing fluid that expands to break the glass at a predetermined temperature, to release the plug and allow water to flow through the outlet. In accordance with conventional practice the said predetermined temperature at which the plug is released may be of the order of 68 °C. The sprinkler device may have a housing to which the releasable cover plate is connected to hide the sprinkler outlet from view. The housing may be a moulded plastics body e.g. a moulded cylindrical body. Preferably, the cover plate is attached to the housing of the sprinkler device by one or more heat-fusible or heat-rupturable retention links. Most preferably, the said retention link or links are arranged so as to fuse or rupture in correspondence with operation of the sprinkler outlet, e.g. at a temperature of the order of 68 °C. In one embodiment the (or each) heat-sensitive link between the cover plate and the housing comprises a body of solder which melts to disrupt the link and thereby allows the cover plate to fall under its own weight at the predetermined temperature. Other arrangements are however also possible. For example, the cover plate may be held to the housing by attraction between magnets provided respectively on the cover plate and the housing whereby on reaching the predetermined temperature the (or each) magnet on one of the cover plate and housing (e.g. on the cover plate) reverses in polarity so that attraction between the magnet turns to repulsion which displaces the cover plate. It may also be possible to link the cover plate and the housing by glass-bulb links or the like which burst and separate at the predetermined temperature. The cover plates may comprise a circular plate made from metal and/or plastics. Other shapes and/or materials may also be used. The (or each) link between the cover plate and the housing may be defined via the intermediary of an elongate linking member or prong which is connected at one end to the cover plate via the heat fusible or heat rupturable link and is mechanically attached at its other end to the housing. This mechanical attachment may be permanent or releasable and may take any suitable form including adhesive, mechanical interlock and the like. In a particularly preferred embodiment the mechanical attachment comprises interengagement of cooperable configurations particularly insertion or plugging in of a barbed or ratchet end of the linking member into a socket having a cooperable retaining structure on the housing. Most preferably the plate has two upstanding linking members preferably at diametrically opposed positions. The electrical sensor may be connected to a remote alarm which may be of any suitable kind, preferably having an internal sounder and an external siren that sound when the alarm is actuated by the electrical sensor. Most preferably a sprinkler " system has a plurality of like sprinkler devices disposed in different zones within a building or other premises or area connected to a common alarm arranged so that the alarm can identify the electrical sensor or sensors that actuated the alarm, indicating which sprinkler device or devices have operated and, if desired, permitting 'zone control' whereby the area(s) in which sprinkler devices have operated can be identified and isolated from other parts of the building. The alarm may include an LCD display or other visual device to provide information. The sensors may be individually wired to the alarm by respective pairs of wires or by respective single wires in combination with a common earth or the like. Alternatively, there may be one or more common buses linking the sensors to the alarm with respective differently addressed components associated with the sensors whereby the sensors can communicate individually with the alarm via the common bus or buses by virtue of a 'polling' operation whereby the alarm periodically checks the individual sensors at their addresses, or by feed of address coded signals to the alarm from a respective actuated sensor. The electrical sensor functions to provide a signal by virtue of the change in the said electrical parameter indicative of an increase in temperature to (or a predetermined relationship to) the predetermined threshold level at which operation of its respective sprinkler device occurs. In a preferred embodiment, the electrical parameter comprises electrical conductivity through the cover plate, or through a component physically associated with the cover plate in that such conductivity is removed when the cover plate falls. Thus, the electrical circuit may include two connectors which are electrically linked by contact with the cover plate itself, or a component attached to or incorporated in the plate. Where the plate is made from conductive material or has a conductive part (e.g. a strip or wire bonded to or moulded in a plastics plate) the connectors may rest on the conductive material or conductive part so as to be normally conductively bridged thereby. Good contact may be achieved by weight or spring pressure. Alternatively, the conductors may be attached to the conductive material or to the conductive part via a heat-fusible or heat-rupturable conductive link so that the conductors are normally bridged but the link disrupts to break the connection and allow fall of the cover plate at the predetermined temperature. The link may be the aforementioned solder link or magnetic attraction. In a particularly preferred embodiment the connectors are provided by the elongate linking members mentioned above. Where such linking members are plugged into sockets on the housing insulation of the sockets relative to each other through the housing may be achieved by use of a housing material such as plastics which is inherently non-conductive or by insertion of insulating material between the sockets and the housing. As an alternative to the use of conductors which are normally conductively bridged by the cover plate other arrangements possibly involving other electrical parameters are also possible. Thus, for example, the conductors may be normally open but are momentarily bridged to give a trigger signal when the cover plate falls; the cover plate or a component physically associated therewith may have a changeable electromagnetic or capacitive or magnetic influence on an adjacent coil or plate or semi¬ conductor or other device. The sprinkler systems of the invention are particularly suitable for use with sprinkler outlets to be plumbed into a known distributor system. Thus, each sprinkler outlet is preferably installed at a distributor head. This is particularly advantageous for the installation of sprinkler systems in new buildings, as it allows the sprinkler system to be installed at negligible extra cost. According to a third aspect of the present invention there is provided a sprinkler system having a plurality of sprinkler devices as described above and a common alarm connected to the alarm sensors. According to a fourth aspect of the present invention there is provided a sprinkler system having a plurality of sprinkler devices each comprising a sprinkler outlet closed with a heat-fusible or heat-rupturable plug and an alarm sensor arranged for actuation in correspondence with the operation of the sprinkler outlet by heat fusion or rupture of the plug, and an alarm connected to the alarm sensors of the sprinkler devices, characterised in that the sensors are operational wholly independently of flow within the sprinkler system and the alarm is arranged to provide an indication of the identity of an actuated said sensor. With this arrangement, the sensors are not responsive to fluid flow in the sprinkler system, nor do the sensors provide any control over the fluid flow as for example by opening flow valves or switching on pumps, whereby accurate convenient alarm monitoring can be achieved with a 'fresh' water system: a stagnant or dry system is not required. With the fourth aspect of the present invention the sprinkler devices may be as described in connection with the first or second aspects of the invention. The invention will now be described further by way of example only and with reference to the accompanying drawings in which: Figure 1 is a diagrammatic representation of one form of a sprinkler system according to the present invention; Figure 2 is a diagrammatic cross-sectional side view of a sprinkler outlet according to the present invention. As shown in Figure 1 , a sprinkler system which may be installed in a building of domestic or commercial premises has a plurality of sprinkler devices 1 at different positions in different rooms of different zones of the building. The sprinkler devices 1 are connected to a water mains supply pipe 2. Each sprinkler device 1 , as will be described in more detail hereinafter, incorporates a respective alarm sensor 3. The sensors 3 are connected to an alarm device 4, a power supply 5, an internal sounder 6 and an external siren 7. The alarm device 4, power supply 5 and internal sounder 6 are mounted at a central location remote from the sprinkler devices 1 . The external siren 7 may be mounted at the same or different remote location. As shown in Figure 2 each sprinkler device has a moulded plastics body part 8 with a cylindrical wall 9, an open bottom end 10, and a top end closed by an integral disc-shaped end wall 1 1 . In the centre of the top end wall 1 1 there is set a threaded metal (e.g. brass) tube 12 which projects at one end above the end wall 1 1 and at its other end downwardly within the cylindrical wall 9. Instead of the metal tube an integral moulded plastics tube or sleeve may be used. The upper projecting end of the tube 12 is screwed into a connection piece 13 in the mains supply pipe 2. On the other end of the tube 1 2 there is screwed a metal frame member 14 containing a glass bulb 15 partially filled with liquid. The bulb 1 5 is held tightly between a lower support abutment 16 within the frame member 14 and a sealing plug 17 within the tube 12. The glass bulb 1 5 holds the plug 17 tightly within the tube 12 so as to seal this and prevent escape of water even at mains pressure. Beneath the frame member 14 there is a transverse vaned or slotted disc 18 rotatably mounted on the frame member 14. The arrangement so far described is generally conventional. In the event that the bulb 15 is heated above a predetermined temperature (usually 68 °C), as would happen in a fire, the bulb 15 bursts allowing the plug 17 to be displaced by water pressure. Water sprays out of the tube and is deflected by the vanes or slots of the disc 18 to provide a diffuse spray over a wide area. In accordance with conventional practice the body part 8 of the sprinkler device 1 may be set within a ceiling of the building and a metal (e.g. brass) cover plate 19 may be fixed over the open bottom of the cylindrical wall 9 to conceal the sprinkler device 1 from view. This cover plate 19 is conventionally attached to the cylindrical wall 9 by means of solder which melts at a predetermined temperature (say 68 °C) to allow the plate 19 to fall away. In accordance with the present embodiment the cover plate 19 is held in position by means of two upstanding metal (e.g. brass) rods 20. The cover plate 19 is disc-shaped having a flat central part with an upwardly displaced rim. The rods 20 extend from the rim at right angles to the central part at diametrically opposed positions. The rods 20 are fixed to the cover plate at their bottom ends by means of solder 20a which melts at the aforesaid predetermined temperature to allow separation of the cover plate 19 from the rods 20. At diametrically opposite positions on the outer surface of the cylindrical wall 9 there are fixed axially extending downwardly open tubular sockets 21 containing internal ratchet or barb elements. The sockets 21 are made from a conductive metal, such as brass, and have screw fittings 22 at their top ends for connection of electrical leads 23. The rods 20 have complementary ratchet or barb configurations 24 at their top ends defined by springy projections. The cover plate 19 can be fitted in position by inserting the top ends of the rods 20 into the sockets 21 . The rods 20 are pushed in until the cover plate 19 is in the required position. The rods 20 then lock tightly in position due to the springy ratchet/barb arrangement and cannot be pulled out. The rods 20 and brass cover plate 19 act to define an electrically conductive bridge between the electrical fittings 22. A signal is thereby supplied to the alarm via the leads 23 from the alarm sensor comprising the connectors 22, sockets 21 , rods 20 and cover plate 19. In the event that the temperature reaches the predetermined level causing the solder between the rods 20 and the cover plate 19 to melt in the vicinity of any of the sprinkler devices, the cover plate 19 fails away and this immediately breaks the conductive bridge between the fittings 22. An appropriate signal is supplied to the alarm 4 which is triggered so as to operate the sounders 6, 7. The alarm 4 has an LCD display panel which indicates the location of the sprinkler device 1 which has triggered operation of the alarm 4. This indication may identify the particular sprinkler device (or devices) or may identify the zone of the sprinkler device 1. With this arrangement, the alarm sensors operate wholly independently of the water flow, they do not respond to water flow pressure, nor do they control the pressure in any way. Thus, the system described can be used with a fresh water main supply system, it is not restricted to use with a stagnant water or dry system. Moreover, each sprinkler device has its own independent alarm sensor whereby the exact location of a rise in temperature signifying a fire condition can be monitored and identified. These benefits are attained with a particularly simple, convenient and inexpensive construction; it is, for example, not necessary to provide expensive or complicated alarm sensor devices at each sprinkler device. Essentially it is only necessary to attach electrical leads to the constructional parts of the sprinkler device. It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only. Thus, for example, although the system has been described in relation to a conventional water supply system, the sprinkler arrangement is particularly suitable for use with a distributor-type water supply system whereby mains water is fed in a loop to a series of distributor heads from which branch supply lines to domestic water devices such as taps, toilets, etc., are run. In this case, the sprinkler outlets can be connected to or integrated in the individual distributor heads whereby the sprinkler system can be installed at the same time as initially the water supply system at little or no additional cost. Also, whilst reference has been made to a particular combination of plastics and metal components it is to be understood that other arrangements may also be used. For example, the cover plate may also be of plastics construction with an attached component (such as an embedded wire) to provide conductivity between the rods.

Claims: CLAIMS 1 . A sprinkler device for a sprinkler system having a sprinkler outlet (12) closed with a heat-fusible or heat-rupturable plug (1 5, 17), a component (19) which is adapted to move or change at. a predetermined temperature to cooperate with sprinkler operation, and an alarm sensor (19-22) arranged for actuation in correspondence with operation of the sprinkler outlet by heat fusion or rupture of the plus, characterised in that the alarm sensor comprises an electrical circuit having an electrical parameter determined by the said component (19) whereby such parameter changes when the component (19) moves or changes. 2. A sprinkler device for a sprinkler system having a sprinkler outlet (12) closed with a heat-fusible or heat-rupturable plug (15, 17), a cover plate (19) beneath the outlet (12) mounted relative thereto by a heat-sensitive connection (20a) which allows the cover plate (19) to fall away to expose the outlet at a predetermined temperature, and an alarm sensor (19-22) arranged for actuation in correspondence with operation of the sprinkler outlet by heat fusion or rupture of the plug (15, 17), characterised in that the alarm sensor (19-22) comprises an electrical circuit having an electrical parameter defined by the cover plate (19) whereby such parameter changes when the cover plate (19) falls away. 3. A sprinkler device according to claim 2 characterised by the provision of a deflector plate (18) beneath the outlet (12). 4. A sprinkler device according to claim 2 or 3 characterised in that the heat fusible or heat rupturable plug (15, 1 7) incorporates a fluid- containing glass tube or bulb (15) which is breakable on thermal expansion of the fluid. 5. A sprinkler device according to any one of claims 2 to 4 characterised in that the cover plate (19) is connected to a housing (8) of the sprinkler device. 6. A sprinkler device according to claim 5 characterised in that the cover plate (19) is connected to the housing by one or more heat fusible or heat rupturable links (20a). 7. A sprinkler device according to claim 6 characterised in that the (or each) link (20a) comprises a body of solder. 8. A sprinkler device according to claim 5 characterised in that the cover plate (19) is connected to the housing by attraction between one or more pairs of magnets. 9. A sprinkler device according to any one of claims 5 to 8 characterised in that the (or each) link (20a) between the cover plate (19) and the housing (8) is via the intermediary of an elongate linking member (20) which is connected at one end to the cover plate (19) via the heat fusible or heat rupturable link (20a) and is mechanically attached at its other end to the housing (8). 10. A sprinkler device according to claim 9 characterised in that the mechanical attachment comprises insertion of a barbed or rachet end (24) of the linking member (20) into a socket (21 ) having a cooperable retaining structure. 1 1 . A sprinkler device according to claim 9 or 10 characterised in that there are two upstanding linking members (20) at diametrically opposed positions on the cover plate (19). 12. A sprinkler device according to any one of claims 2-1 1 characterised in that the electrical circuit includes two connectors (20) linked by contact with the cover plate (19) or a component physically associated with the cover plate. 13. A sprinkler device according to claim 12 when dependent on claim 9 wherein the connectors (20) are provided by the said linking members. 14. A sprinkler system having a plurality of sprinkler devices according to any one of claims 2 to 13 in combination with an alarm (4) connected to the alarm sensors (19-22). 15. A sprinkler system according to claim 14 characterised in that the alarm is operable to provide an indication of the location of an actuated said alarm sensor. 16. A sprinkler system having a plurality of sprinkler devices (1 ) each comprising a sprinkler outlet (12) closed with a heat-fusible or heat-rupturable plug (15, 17) and an alarm sensor (19-22) arranged for actuation in correspondence with the operation of the sprinkler outlet by heat fusion or rupture of the plug (15, 1 7), and an alarm (4) connected to the alarm sensors (19-22) of the sprinkler devices (1 ), characterised in that the sensors (19-22) are operational wholly independently of flow within the sprinkler system and the alarm (4) is arranged to provide an indication of the identity of an actuated said sensor (19-22).

Inventors: BIRKETT DAVID, BUTLER WILLIAM ANTHONY, BIRKETT, DAVID, BUTLER, WILLIAM, ANTHONY
Applicants: BIRKETT DAVID, BUTLER WILLIAM ANTHONY, BIRKETT, DAVID, BUTLER, WILLIAM, ANTHONY
Application year: 2001
Main classification: A62C35
IPC codes: A62C35, A62C37