EP0139049B1

EP0139049B1 - Automatic fire extinguisher

Info

Publication number: EP0139049B1
Application number: EP83201505A
Authority: EP
Inventors: Kiyoshi Kato
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-10-20
Filing date: 1983-10-20
Publication date: 1988-07-13
Also published as: ATE35626T1; DE3377333D1; EP0139049A1

Abstract

An automatic fire extinguisher including a tank (44) filled with fire extinguishing solution and a gas vessel (10) contained with pressure applying medium for applying pressure to the solution within the tank (44), and the sealing portion (12) of the gas vessel (10) is opened by released resilient energy of a resilient member (76) which is held in a compressed state by a heat sensitive mechanism (90). The compression is released at a predetermined temperature and as a result the fire extinguishing solution is pressurized and an alarm is sounded.

Description

The invention relates to an automatic fire extinguishing system composed of a plurality of fire extinguishers each including a tank containing a fire extinguishing solution therein and having nozzles for ejecting said solution, a gas vessel filled with pressure applying medium for applying pressure into said tank and having a sealing cap at one end, a connector secured to said vessel and said tank and having a gas conduit through which said pressure applying medium is guided into said tank when said sealing cap is broken, a striker slidably mounted in said connector at a position opposite to said sealing cap for breaking said sealing cap, a frame secured to said connector and accomodating a hammer adapted to apply impact to said striker and a spring for urging said hammer towards said striker, a holder secured at one end to said hammer and at the other end clamped to said frame by a set screw secured to said frame for holding said hammer against the force of said spring, and a heat fusible element housed within a tubular member interposed between said holder and said screw and being fusible out of said tubular member under the heat generated by the fire for unlocking said holder.
There has been proposed such a fire extinguisher, as shown in United States patent 4,299,289 granted to the same applicant as the present application, which has been designed such, that when it is detected that the room temperature increases to an abnormally high temperature, a coil spring which is previously compressed by a holder is released from the holder to push a striker with a knife edge by means of the spring force of the coil spring against the seal of a tank filled with liquid carbon dioxide, thereby to break the seal of the tank, and then the fire extinguishing solution contained in the tank is ejected out from the nozzle of the tank by the aid of pressure of the evaporated gas. Further is provided a heat fusible element between the holder and a screw adapted to apply pressing force to the holder, and if the heat fusible element is molten owing to the abnormally high temperature, the above mentioned compression condition of the coil spring is released.
The fire extinguisher as mentioned above is designed to be secured to a ceiling and the like, and the number of the fire extinguishers is decided in accordance with the area of floor to be disposed with the fire extinguishers and the density of combustible objects. An alarm device for giving an alarm sound upon detection of abnormally high temperature within the room is sometimes used in conjunction with the fire extinguishers for the purpose of fire extinguishing operation at the initial stage of fire, however such an alarm device operates by a mechanism independent and different from the fire extinguishers. Therefore it has been usual that the ejection of the fire extinguishing liquid from the fire extinguisher is made before the alarm sound by the alarm device, or vice versa.
Further in the case where a plurality of the fire extinguishers are disposed, since the heat sensitive portion, i.e. heat sensor, of each fire extinguisher independently operates, even when the nearmost fire extinguisher from the position at which fire is occured operates, it is usual that the fire extinguishers adjacent to the nearmost fire extinguisher do not operate until the heat sensor of each of the adjacent fire extinguishers detects the fact that the detecting temperature is raised to a predetermined operation temperature. Therefore there is a problem that in the case where a large amount of combustible objects is disposed at the position adjacent to the fire occured position, it will not be possible to protect the combustible objects from the spread of the fire.
The object of the present invention is to provide an automatic fire extinguisher system designed such that when one of the plural fire extinguishers composing a group operates, an alarm sounds simultaneously and other fire extinguishers within the group are also simultaneously operated.
According the invention this can be obtained in, that each extinguisher includes a heat emitting element for forcibly melting said heat fusible element when supplied with electrical power, a switching mechanism having a switching member and means for mechanically actuating said switching member upon the movement of said striker or said hammer, said switching members and said heat emitting elements of said plurality of fire extinguishers being electrically connected to a common electrical power source and a common alarm device, so that, when one of the switching members is actuated, the electrical power is supplied to the alarm device and to all of said heat emitting elements.
It is noted that from AU-B-471,307 it is known to combine individual extinguishers in a system whereby the sensing of abnormally high temperature and resultant operation of one extinguisher in the system causes others to operate by means of supplying electricity to a heating element on each other extinguisher in order to simulate abnormally high temperatures and thereby cause actuation of those other extinguishers. The heating elements may act on fusible links.
A micro-switch serves to operate via a line an alarm which is common to all of the extinguishers in the system. However, because the output from the micro-switch is fed through "AND" gates such, that either a pressure-sensitive switch or a weight-sensitive switch must also close before the alarm can operate, the alarm would not operate at the moment of firing of the extinguisher.
The above and other objects, features and advantages of the present invention will be apparent from the following detailed descriptions of the preferred embodiments of the present invention in connection with the accompanying drawings, in which:

Figs. 1-3 show an embodiment of an automatic fire extinguisher of the present invention; Fig. 1 is a sectional view of the automatic fire extinguisher in a mounted condition; Fig, 2 is an enlarged sectional view of a heat sensitive portion in Fig. 1; and Fig. 3 is a circuit diagram for explaining the generation of alarm sound.
Figs. 4 and 5 show another embodiment of an automatic fire extinguisher of the present invention; Fig. 4 is an enlarged sectional view of a heat sensitive portion and Fig. 5 is a circuit diagram for explaining the simultaneous operation of a group of fire extinguishers.

Referring to Figs. 1-3 an embodiment of the present invention is shown in Fig. 1, numeral 10 designates a vessel contained with liquid carbon dioxide as pressure applying medium. The vessel 10 has a foremost part provided with a cap 12 for sealing. The vessel 10 is housed within a casing 14 with the foremost parts downwards. The casing 14 has a mounting fixture 16 at the upper end and is designed to be secured to the rafter 20 of the ceiling at the mounting fixture by the screws 18. An inner cylindrical connector 22 is fitted to the foremost part of the gas vessel 10 as shown in Fig. 1. A striker 24 Having a knife edge 26 for breaking the sealing cap 12 at the end point of the striker 24 is mounted slidably axially within the connector 22 in the case of a fire. An O-ring 28 is interposed between the gas vessel 10 and the inner connector 22, and another O-ring 30 is also interposed between the striker 24 and the inner connector 22 as shown in Fig. 1. An outer connector 32 is fitted on the inner connector 22 and sealed therefrom by a pair of O-rings 34 and 36 at the upper and lower positions respectively. The outer connector 32 has a central flange portion 38 and is engaged by an upper nut 40 and a lower nut 42. Numeral 44 designates a toroidal or doughnut-shaped tank for receiving the fire extinguishing solution 45. The upper and lower flanges 46 and 50 of the tank 44 are connecated to the central flange portion 38 of the outer connector 32 through seal members 48 and 52 respectively. The outer connector 32 is formed with a plurality of radial gas conduits 56 for directing the gas within the gas vessel 10 into the tank 44 containing the fire extinguishing solution. When the sealing cap 12 is broken by impact afforded by the striker 24, the gas in the vessel 10 flows into the tank 44 filled with a fire extinguishing solution 45. The gas contained in the gas vessel 10 may be supplied to the conduits 56 by way of ports or orifices 60 formed in the inner connector 32. These ports 60 are usually closed by a tube or valve 62 made of rubber or similar material which is fitted into the ports 60. The valve 62 may be ruptured only when the carbon dioxide gas has been ejected from the gas vessel 10 to permit the carbon dioxide gas to flow into the tank 44.
The fire extinguishing solution 45 within the tank 44 may be ejected into the space below through a nozzle device 64 along with the carbon dioxide gas contained in the gas vessel 10. The nozzle device 64 has, as shown in Fig. 1, a dome- shape configuration formed with a number of ejection openings 66 and a diaphragm 70 made of rubber or similar material. The diaphragm 70 is designed for normally blocking the fire extinguishing solution 45 from flowing therethrough and to be ruptured only when the liquid carbon dioxide contained under elevated pressure within the gas vessel 10 flows into the tank 44 upon breakage of the sealing cap 12 to permit the fire extinguishing solution 45 to flow into the space therebelow along with the carbon dioxide gas.
Numeral 72 designates a frame fixed to the outer connector 32 at the upper end portion thereof. Within the frame 72, a hammer 74 for impinging the striker 24 and a compression coil spring 76 acting resiliently on the hammer 74 are disposed. A holder 77 is secured at the upper end thereof to the hammer 74 and engaged at the inclined lower end of the holder 77 by the lower end 73 of the frame 72 so as to retract the hammer 74 downwards against the force of the compression coil spring 76. A guide member 78 is threadedly mounted to the hammer 76 for guiding the coil spring 76 into contact with the lower face of a flange 80 of the hammer 74.
Numeral 84 designates a heat sensitive portion for detecting the abnormally high temperature within the room. The heat sensitive portion 84 is interposed between the holder 77 and a screw 82 disposed at the lower end portion of the frame 72. The screw 82 is disposed to press the holder 77 against the inclined surface 73 of the frame 72 thereby to lock the holder 77. The heat sensitive portion 84 is composed of a heat insulating member 86 contacting the holder 77, a heat sensitive plate 89 having a heat conducting portion 88 extending toward the outer space of the fire extinguisher body and secured to the heat insulating member 86, a tubular member 92 secured to the heat sensitive plate 89 and having a heat fusible element 90 therein, and a plunger 94 having one end contacting with the heat fusible element 90 contained within a tubular member and the other end engaging the screw 82. The heat fusible element 90 is made of low melting alloy material having a melting point of about 72°C. The lower portion 75 of the holder 77 is bent to be able to engage the inclined surface 73 of the frame 72, and the holder 77 may be engaged to the frame 72 through the heat sensitive portion 84 by means of the compression force due to the set screw 82, thereby holding the spring 76 in a compressed condition. When the low melting alloy material melts, the engagement between the holder 77 and the frame 72 is released to push up the striker 24 by the hammer 74 by way of the resilient force due to the spring 76.
Further there is provided in the frame 72 a through hole 96 at the position corresponding to the lower end portion of the striker 24, as shown in Fig. 1, and a plate like member 98 is inserted within the through hole 96. The plate like member 98 has one end which is bent at the peripheral surface of the frame 72, and a microswitch 100 is fixed at the bent portion of the plate like member 98. The other end portion of the plate like member 98 is also bent at the peripheral surface of the frame 72, and an opening 102 is formed at the central portion of the plate like member 98 to permit a free passage of the lower end portion of the striker 24. The microswitch 100 is moved in an upward direction along with the plate like member 98 when the hammer 74 impinges the lower end portion of the striker 24, and is designed to be actuated to ON-state when the microswitch 100 contacts the lower surface of the lower nut member 42. The microswitch 100 is used for the purpose of actuating a buzzer 104 secured to the casing 14 for giving alarm sound.
Referring to Fig. 3 a circuit diagram for actuating the buzzer 104 is shown. As is apparent from Fig. 3, the microswitch 100, buzzer 104, and an electric power source 106 are connected in series thereby giving the alarm sound due to the buzzer 104 upon the actuation of the microswitch 100.
The generation of the alarm sound is almost simultaneous with the initiation of the ejection due to the automatic fire extinguisher.
According to the automatic fire extinguisher thus constructed, the synchronization between the generation of alarm sound and the initiation of ejection means the fact that an initial fire extinguishing action is made no sooner than the generation of alarm sound because of fire occurrence, and further a real fire extinguishing action may immediately start even if the initial fire cannot completely be extinguished by the initial fire extinguishing action.
Referring now to operation of the extinguisher, when the room temperature reaches to an abnormally high temperature such as about 72°C because of fire and similar phenomenon, the heat sensitive plate 89 also reaches a high temperature and the heat of the heat sensitive plate 89 is quickly transmitted to the low melting alloy material 90 through the tubular member 92, because the transmission of the heat in the counterdirection to the tubular member 92 is disconnected by the heat insulating member 86, thereby melting the low melting alloy material 90. When the low melting alloy material 90 is melted and thereby deformed the compression force by which the holder 77 is compressed to the frame 72 is eliminated to disconnect the engagement therebetween, and then the hammer 74 moves upwardly by the resilient force due to the spring 76. The hammer 74 pushes up the lower end portion of the striker 24 and further the plate like member 98 fixed with the microswitch 100 is also moved upwardly. The knife edge 26 formed at the upmost portion of the striker 24 opens the sealing cap 12 of the gas vessel 10, and further the actuator of the microswitch 100 is depressed by the lower surface of the lower nut 42 thereby to make the microswitch 100 ON-state and to give alarm sound due to the buzzer 104. The carbon dioxide gas ejected by opening of the sealing cap 12 passes through the conduits or orifices 60, the backward flow preventing valve 62 and the gas conduits 56 to reach to the tank 44 containing the fire distinguishing solution 45, and the solution 45 is compressed to break the diaphragm 70 of the nozzle devices 64 and to eject the solution 45 from the dome shaped cap, or ejection holes 66, to the room.
The electric power source 106 to be used for the embodiment of the present invention may be the dry battery usually sold at a market, but it is preferable from the point of view of avoiding a natural discharge of the electric power to use a lithium battery. Further a magnetoelectric buzzer is preferable for the buzzer 104, and the microswitch 100 is used in the above embodiment as means for accurately actuating the buzzer 104 in synchronism with the initiation of the ejection of the fire extinguishing solution, however the present invention should not be limited to the microswitch but may be means for accurately closing the circuit for the buzzer immediately upon detection of movement of the holder 77 or the striker 24. For example, it may be designed that a switch is composed of a pair of conductors, one is mounted on the upper end portion of the hammer 74 and the other is mounted on the lower end portion of the striker 24, and the switch thus arranged may be turned to ON-state by contact of the hammer 74 and the striker 24. Further, it also may be designed that there is provided an elongated through slit at the frame 72 and a projection formed at the portion of the upper end portion of the hammer 74, the projection being projected through the elongated slit, and then the microswitch 100 is pressed by the projection of the hammer 74 upon striking of the hammer 74 against the striker 24.
As mentioned above, the main body of the automatic fire extinguisher is mounted inside of the ceiling 140 of the room, therefore the lower portion of the frame 72 including the heat sensitive plate 89 and the nozzle device 64 including the solution ejecting hole 66 are merely exposed from the ceiling 140, thus the main body of the fire extinguisher except the portions exposed to the room is disposed behind a cover 142, so that a fine view of the room is not failed.
Referring now to Figs. 4 and 5, details of the automatic fire extinguisher system of the present invention are shown. The fire extinguishing system of the invention is designed such that a plurality of automatic fire extinguishers are divided into some groups, in each group a plurality of automatic fire extinguishers have the same construction as others in the group. The automatic fire extinguishing system is designed such that when one of the automatic fire extinguishers in a single group operates in response to the abnormally high temperature of the room, all of other automatic fire extinguishers in the group are operated in synchronism with each other. Each fire extinguisher according to the automatic fire extinguishing system has essentially the same configuration as that shown in Figs. 1 and 2, except such construction that nichrome wires 212 as a heat emitting body are disposed adjacent to the low melting alloy material 218 in the heat sensitive portion 200. Thus, the heat sensitive portion 200 is composed of heat insulating member 210 contacting the holder 77, a heat sensitive plate 214 fixed at the surface of the heat insulating member 210 opposite to the surface contacting the holder 77, and a tubular member 216 secured to the heat sensitive plate 214 and filled with the low melting alloy material, i.e. a low temperature solder 218 therein, the low temperature solder 218 being sealed by a plunger 220. The plunger 220 is pressed by a set screw 222 mounted on the frame 72 thereby contacting the holder 77 against the frame 72 by means of the compression force due to the set screw 222. The nichrome wires 212 are disposed at the space enclosed by the heat insulating member 210, and has a small air gap from the heat sensitive plate 214. Further the nichrome wires 212 emit heat upon application of electric power, and the emitted heat energy is transmitted to the low temperature solder 218 through the heat sensitive plate 214 and the tubular member 216, thereby to melt the low temperature solder 218. The transmission of the heat energy is prevented in the direction towards the holder 77 by the heat insulating member 210, therefore the heat energy is effectively transmitted to the low temperature solder 218. The low temperature solder 218 is usually depressed to the tubular member 216 through the plunger 220 by the set screw 222, but when the solder 218 is molten by receiving the heat energy due to the heated nichrome wires 212, the pressing force applied to the holder 77 is eliminated thereby to release the inclined surface of the holder 77 from the frame 72. As mentioned above the low temperature solder 218 is applied with pressing force through the plunger 220 by the set screw 222, and a deformation of the low temperature solder 218 scarcely occurs except the deformation due to the abnormally high temperature, therefore if the set screw 222 is fixedly set, the inclined surface 78 of the holder 77 is fixedly engaged with the lower end portion of the frame 72. This insures that any malfunction of the automatic fire extinguisher due to a physical characteristic of the low temperature solder 218 does not occur.
Referring to Fig. 5 a connection condition between the nichrome wires 212A to 212F and the switches 100A to 100F of the six automatic fire extinguishers composing one group of the automatic fire extinguishing system is shown. One end of each nichrome wire out of the wires 212A, 212B, 212C...212F is connected to one end of each of the corresponding microswitches 100A, 100B, 100C...100F and to one end of the buzzer 104 which is used in common. The other end of each nichrome wire is connected to one end of the electric power 106, and the other end of each microswitch is connected to the other end of the elecric power 106. It may be sufficient to connect the buzzer 104 to either one of the fire extinguishers composing the single group. In the above embodiment shown in Fig. 5 one group composed of six fire extinguishers is shown, it also may be designed to compose one automatic fire extinguishing system having a plurality of groups of the automatic fire extinguishers in accordance with the area of the floor of the room to be provided with the automatic fire extinguishing system and the density of combustible objects. According to the automatic fire extinguishing system composed of plural groups thus designed, in case of occurrence of fire only one automatic fire extinguisher of a single group, which is most near to the occurrence position of fire, is operated by the fact that the heat sensitive portion of the nearmost fire extinguisher is actuated in response to the abnormally high temperature of the room. Namely the heat conducting portion of the heat sensitive plate 214 is heated, and the heat is effectively transmitted to the low temperature solder 218, and then when the temperature of the solder 218 reaches to a predetermined temperature about 72°C, the compression force applied to the frame 72 through the holder 77 is eliminated because of the melting of the low temperature solder 218 thereby to release the holder 77 from the frame 72. Then the hammer 74 moves upwardly by the resilient force due to the spring 76 to strike the lower end portion of the striker 24. As a result, the microswitch fixing plate 98 is also moved upwardly to actuate the microswitch 100, which results in the closed state of the microswitch 100. The microswitch may be one of the six microswitches 100A, 100B, 100C...100F shown in Fig. 5, and by closing one microswitch all nichrome wires 212A, 212B, 212C...212F within one group are connected to the electric power 100 by closing the electric circuit connecting the nichrome wires to the electric power 106, and further the electric circuit connecting the buzzer 104 to the electric power 106 is also closed thereby to give alarm sound. As a result, all of the six nichrome wires within the same group are heated to actuate all of six fire extinguishers within the same group and to eject the solution from all of six tanks thereof, even though the ambient - temperature does not reach to the predetermined temperature with respect to at least four fire extinguishers. Alarm sound due to the buzzer 104 is also given at the same time as the initiation of the ejection of the fire extinguishing solution.
According to the automatic fire extinguishing system thus operated, the spread of fire of combustible objects disposed within the region covered by one group of the fire extinguishers can be entirely prevented. However the fire extinguishers of another group or groups do not operate to eject the solution thereof, until the ambient temperature reaches the predetermined temperature. Further the number of the fire extinguishers composing one group may be freely decided in accordance with the condition of floor, therefore in the case of the floor having large density of combustible objects the single group may be composed of many more fire extinguishers.
In Fig. 4 the heat sensitive plate 214 is formed in L-letter shape in section and made of copper, and it is of course necessary to design the area of the heat conducting portion expanded outside the main body of the fire extinguisher in view of thermal capacity of the material used for the heat conducting portion, in order to be able to transmit the heat energy due to abnormally high temperature to the low temperature solder 218. Further in Fig. 4 a usual nichrome wire is used as a heat generating body, however the present invention should not be limited to a nichrome wire, but any material capable of generating heat required for melting the low temperature solder by applying electric power can be usable.
The Figures used in the claim are only meant to explain more clearly the intention of the invention and are not supposed to be any restriction concerning the interpretation of the invention.

Claims

Automatic fire extinguishing system composed of a plurality of fire extinguishers each including a tank (44) containing a fire extinguishing solution therein and having nozzles (64) for ejecting said solution, a gas vessel (10) filled with pressure applying medium for applying pressure into said tank (44) and having a sealing cap (12) at one end, a connector (32) secured to said vessel (10) and said tank (44) and having a gas conduit (56) through which said pressure applying medium is guided into said tank (44) when said sealing cap (12) is broken, a striker (24) slidably mounted in said connector at a position opposite to said sealing cap (12) for breaking said sealing cap (12), a frame (72) secured to said connector (32) and accomodating a hammer (74) adapted to apply impact to said striker (24) and a spring (76) for urging said hammer (74) towards said striker (24), a holder (77) secured at one end to said hammer and at the other end clamped to said frame (72) by a set screw secured to said frame (72) for holding said hammer against the force of said spring, and a heat fusible element (218) housed within a tubular member (216) interposed between said holder (77) and said screw (222) and being fusible out of said tubular member under the heat generated by the fire for unlocking said holder (77), each extinguisher including a heat emitting element (212) for forcibly melting said heat fusible element (218) when supplied with electrical power, a switching mechanism having a switching member (100) and means (42, 98) for mechanically actuating said switching member upon the movement of said striker (24) or said hammer (74), said switching members (100A-100F) and said heat emitting elements (212A-212F) of said plurality of fire extinguishers being electrically connected to a common electrical power source (106) and a common alarm device (104), so that, when one of the switching members (100A-100F) is actuated, the electric power is supplied to said alarm device (104) and to all of said heat emitting elements (212).