GB1598475A

GB1598475A - Automatic fire-extinguishing system

Info

Publication number: GB1598475A
Application number: GB2176678A
Authority: GB
Original assignee: SECURITY PATROLS CO Ltd
Current assignee: SECURITY PATROLS CO Ltd
Priority date: 1978-05-24
Filing date: 1978-05-24
Publication date: 1981-09-23

Description

(54) AUTOMATIC FIRE-EXTINGUISHING SYSTEM (71) We, SECURITY PATROLS CO. LTD., a Japanese Body Corporate, of 9-13 1chome, Akasaka, Minato-ku, Tokyo, Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an automatic fire-extinguishing system, and particularly to an automatic fire-extinguishing system utilizing a fire-extinguishing gas.

In conventional automatic fire-extinguishing systems utilizing a fire-extinguishing gas, a bomb containing a fire-extinguishing gas, such as halon gas, under pressure is provided at a location. Several gas jetting nozzles are arranged at desired locations within a region wherein automatic extinguishing should be effected when a fire occurs therein. The gas jetting nozzles are connected through a valve and a pipe to the bomb. Fire sensors are arranged at desired locations within the region. In response to a fire signal from the fire sensors, the valve opened to cause fire-extinguishing gas to jet from the gas jetting nozzles into the region so that automatic extinguishing can be effected therein.

However, since such conventional automatic fire-extinguishing systems require a complicated system of gas pipes from a gas bomb to the gas jetting nozzles, the cost and installation of the pipes is expensive.

Moreover, since the gas pipes are fixedly arranged in the walls, ceiling etc., of a room defining a region wherein automatic extinguishing should be effected when fire occurs therein, it is not easy to remove the gas pipes and to change the arrangement of the gas jetting nozzles. Furthermore, the gas bomb to be used must have a capacity comparable with the space of the region wherein automatic extinguishing should be effected and, therefore, gas bombs having different capacities must be prepared for different regions. This is very uneconomical.

To eliminate the drawbacks of the abovementioned conventional fire-extinguishing system, G. J. Grabowski et al invented the fire protection apparatus which is disclosed in the U.S. Patent 3,713,491. In this patent, a portable automatic fire proteciton system is disclosed comprising battery powered, independent suppressor units, each including a supply of fire-extinguishing fluid and a fire detector. The connection of the individual unit's control circuits provides a control circuit network that automatically initiates an extinguishing fluid discharge from all units in response to fire detection by any single unit.

Even though the Grabowski et al system eliminates the above mentioned problems of the previous pipe arrangement, the sensing capability of this system is lowered because of the restricted disposition of the fire detector upon each independent suppressor.

Since each suppressor is provided with its own-battery, if a number of suppressors are utilized for the fire-extinguishing system, the cost of the batteries becomes high.

In our U.K. Patent No. 1501349, there is described an automatic fire-extinguishing system, comprising: one or more portable fire-extinguishers, the or each fireextinguisher including a pressure vessel containing a fire-extinguishing gas under pressure and a gas discharge nozzle connected through a valve to said vessel; at least one fire sensor; and a controller for opening the valve, or any or all of the valves, in response to a fire signal from the fire sensor or sensors.

With this arrangement a single controller can operate all of a plurality of separate portable extinguishers in response to one or more sensor which may be located as desired to maximise the likelihood of detecting fire. However, the power supply for actuating the extinguishers of embodiments of the system described in the above Patent has to be capable of actuating all the extinguishers simultaneously.

According to the present invention an automatic fire-extinguishing system comprises a plurality of portable fireextinguishers, each fire-extinguisher including a pressure vessel containing a fire extinguishing gas under pressure and a gas discharge nozzle connected through a valve to said vessel, at least one fire sensor, and a main controller for opening a plurality of the valves in response to a fire signal from the fire sensor or sensors; wherein the main controller is associated with one of the fire-extinguishers and comprises electromechanical means actuatable in response to the fire signal to open the valve of the associated fire extinguisher which thereafter remains open, and gas discharge detecting means responsive to gas discharge from the vessel to the nozzle to terminate actuation of said electro-mechanical means and generate a slave fire signal, the or each of the other fire-extinguishers having slave controllers, connected to one another in successive series from the main controller of said one fire-extinguisher, the or each of the slave controllers having respective said electro-mechanical means and gas discharge detecting means and being responsive to generation of the slave fire signal by the preceding controller of the series to actuate its electro-mechanical means.

With this arrangement the extinguishers are actuated in sequence so the power supply need be capable of powering only one actuation at a time.

The fire sensors (or sensors) may be connected to a DC power source which may be supplied from an AC power source via a conventional transformer and a rectifier or a battery. The above-mentioned controllers may also be connected to the same power supply source. In this automatic fireextinguishing system, the electro-mechanical opening means of the fire extinguishers are actuated one by one in accordance with the connection sequence of the series of controllers. Therefore, a power sourcce of relatively low capacity is required, as compared to an automatic fire-extinguishing system wherein all fire extinguishers are simultaneously actuated in response to a fire signal issued from any one of fire sensors.Since the control circuit of each fire extinguisher is very simple and a pluralitity of control circuits are easily connected in series, the cost of the automatic fire-extinguishing system is greatly reduced.

Preferably, each of the controllers (main and slave) includes a timer relay arranged to generate said slave fire signal a predetermined time delay after receiving a fire signal or slave fire signal as the case may be. Then if any of the controllers or associated fire-extinguishers is faulty, a slave fire signal is still generated to actuate the extinguishers further down the series, even if the gas discharge means of the faulty extinguisher fails to operate by the end of the time delay.

Examples of this invention will now be described with reference to the accompanying drawings in which: FIGURE 1 is a schematic diagram of one embodiment of the automatic fireextinguishing system according to this invention; FIGURE 2A is a schematic side view of a valve for each of the fire extinguishers which is provided with an electromechanical means for actuating the valve; FIGURE 2B is a schematic side view of the valve shown in FIGURE 2A, indicating the open condition thereof; FIGURE 3 is a circuit diagram representing a series of main and slave control circuits for the automatic fire-extinguishing system shown in FIGURE 1; and FIGURE 4 is a circuit diagram of a modified embodiment of the automatic fireextinguishing system.

As illustrated in Fig. 1, a plurality of portable automatic fire extingiushers (No.

1, No. 2, . . .) are placed at desired locations within a region, for example, a room wherein automatic extinguishing is to be effected when a fire occurs therein. The number of fire extinguishers may be selected according to the size and shape of the region.

In this system, the portable automatic fire extinguisher No. 1 comprises a housing 1, a pressure vessel 2, containing a fireextinguishing gas such as halon gas under pressure and accomodated in the housing 1, and a conduit 3 for fire-extinguishing gas extending from the vessel 2 to the outside of the housing. The conduit 3 is provided at its intermediate portions with a valve 4, an internal pressure detecting switch 5 and gas discharge detecting switch 6 and at its end opposite the vessel 2 with a gas discharge nozzle 7.

A power source 8 comprises a transformer and a rectifier, and an electric circuit for indicating the condition of the elements of the automatic fire-extinguishing system. The intermediate power source is connected to a conventional AC power supply source. Instead of utilizing such a power supply system, a battery such as a Nickel-Cadmium battery may be utilized.

To prevent trouble due to an unexpected electric power failure, it is preferable to use an alternatively actuatable power supply system comprising the above-mentioned power source with the battery as back-up.

The portable automatic fire extinguishers (No. 2,. . .) other than the fire extinguisher No. 1 in this system are identical with the fire extinguisher No. 1, without the power source 8. The power source 8 can be mounted on any of the fire extinguishers (No. 2 . . .).

Fire sensors 9 are arranged at desired locations within the region, for example at several positions in the ceiling of a room defining the region. A fire signal from the fire sensors 9 is transmitted over a line Ii to a control box 10 of the first fire extinguisher No. 1.

The sensors 9 receive electric power from the intermediate power source 8 via a line Ln. The earth terminal of the control box 10 of the first fire extinguisher No. 1 is connected to ground in the power source 8. When a signal from any of the fire sensors 9 is transmitted to the control box 10 of the first fire extinguisher No. 1, an electro-mechanical means (Fig. 2) for opening the valve 4 is actuated so that fireextinguishing gas from the vessel 2 is discharged through the conduit 3 and out of the nozzle 7. As a result, the gas pressure in the conduit 3 or ihe nozzle rises rapidly.

The gas discharge detecting switch 6 comprises a bellows (not shown) which is capable of expanding along the axial direction thereof in response tu gas pressure in the conduits and a limit switch (not shown) which is actuated !vy the deformation of the bellows. A conventional gas pressure detecting switch may be used as the switch 6. When the gas contained in the vessel 2 of the first fire extinguisher No. 1 is discharged from the nozzle 7, the switch 6 detects the pressure rise in the conduits and issues a signal to the control box 10 of the second fire extinguisher No. 2, by way of a connection line La, to actuate the next extinguisher. Consequently, a similar electro-mechanical means for opening the valve 4 of the second fire extinguisher No.

2 is actuated to open the valve 4. The control box 10 of the third fire extinguisher No. 3 (not shown) is actuated similarly by a signal issued from the switch 6 of the second fire extinguisher No. 2.

In order to prevent electric power from being supplied to the electro-mechanical means of the valve 4 from the power supply after all of the fire-extinguishing gas in the vessel 2 has been used, the internal pressure detecting switch 5 is arranged adjacent the valve to operate in response to a reduction of the internal pressure in the vessel 2 to prevent the electro-mechanical means from being further energised when all of the fire extinguishing gas has been used.

If more than four fire extinguishers are utilised, the transmission of the signal from the switch 6 of one fire extinguisher to the next in the series is carried out in the same manner as mentioned above. The control box 10 of the first extinguisher (No. 1) can be regarded as a main controller for the entire system generating a slave fire signal on operation of switch 6. The control boxes 10 of the other extinguishers can then be regarded as slave controllers.

With this arrangement, it is not necessary to use a power source having large capacity.

Consequently, a power source having only a capacity sufficient for actuating the sensors 9 and the actuation of a single fire extinguisher can be used.

The entire control circuit of the automatic fire-extinguishing system can be made very easily by simply connecting the control circuits of the component fire extinguishers in series.

In the above-mentioned embodiment of the automatic fire-extinguishing system shown in Fig. 1, if a control circuit of any one of the fire extingiushers, for example that of the fire extingiusher No. 1, does not work for any reason, the control circuit of the downstream fire extinguishers can not work, because of the construction of the assembled control circuit. Therefore, in this condition, the fire-extinguishing system can not operate functionally. To prevent such a problem from occurring, a time control system is applied to each fire extinguisher. The detailed construction and function of this system is hereinafter explained with reference to Fig. 3.

The automatic fire-extinguishing system may be designed to transmit a fire signal over a line L, and a commercial telephone line via an EG station to a remote central monitor.

The automatic fire-extinguishing system of this invention, as described above, requires only one kind of automatic fire extinguisher, such as the fire extinguisher No. 1 and No. 2 described above which have a suitable same capacity. Namely in the present system, a necessary number of the same portable fire extinguishers may be placed at suitable locations within a region according to the size and shape of the region. Therefore, the present system is very economical and flexible, compared with conventional systems wherein many kinds of bombs having different capacities must be prepared. Furthermore, the automatic fire extinguishing system of this invention can be installed in a region merely by placing one or more portable fire extingiushers such as the fire extinguishers No. 1, No. 2, .. ) at suitable locations within the region, but requires no complicated system of pipes from a gas bomb to a number of gas jetting nozzles, which system of pipes would be needed in conventional systems as described hereinbefore.

Therefore, installation and removal of the present system can be very easily effected, and modification of the arrangement of the fire extinguishers can be very easily carried out.

Moreover, in the present system, only one exchangeable intermediate power source 8 may be prepared for the fire extinguisher No. 1 and similar intermediate power source for the other fire extinguishers (No. 2, . . .) may be omitted. As a result a very economical system can be employed.

Referring to Figs. 2A and 2B, the construction and function of the valve 4 disposed in a connection portion between the bomb 2 and conduit 3 extending to the nozzle 7 is explained in detail. A conduit 2a extending from the bomb 2 is provided with a T shaped head portion 2b wherein both ends are opened. One end of the T shaped head portion 2B is threaded and thread engaged with an end of the conduit 3, while the other end of the T shaped head portion 2b is also threaded and thread engaged with a cap 13 so as to seal the opening. The cap 13 is provided with a central aperture which is covered by a metallic or plastic film 13a. The valve 4 is slidably positioned in a cylindrical room of the T shaped head portion 2b. The cylindrical room is composed of a narrow room and a wide room so that a ring shaped wall is formed between these two component rooms as shown in Figs. 2A and 2B.The valve 4 is positioned in the wide room in such a way that when the valve 4 contacts the ring shaped wall, the connection between the conduit 3 and the conduit 2a is interrupted, while when the valve 4 moves away from the abovementioned ring shaped wall toward the cap 13, the conduit 3 is connected to the conduit 2a. The valve 4 is provided with a cylindrical recess 4a (Fig. 2B) coaxially formed therein at the side of the cap 13 and a cylindrical room 12 formed therein as shown in Fig. 2A. The room 12 is connected to outside of the body of the valve 4 by means of a plurality of thin conduits 1 2a which are capable of connecting the room 12 to the conduit 2a only when the valve 4 interrupts the connection between the conduit 2a and the conduit 3.An expansion spring 14 is inserted in a space formed by the cylindrical room 4a and a posisble space between the valve 4 and the cap 13, and consequently, the valve 4 is always urged toward the conduit 3. The spring force of the helical spring 14 is so selected that if the gas pressure in the space involving the spring 14 is reduced by the gas leaking through any possible hole in the film 13a, the pressure imparted to the transversal wall of the cylindrical room 12 exceeds the resistance created by the spring 14, and consequently, the valve 4 is displaced toward the cap 13. An electromechanical means for opening the valve 4 is a solenoid mechanism 16 provided with a needle 15 which is capable of inserting into the film 13a at a center position thereof when the solenoid is actuated.Fig. 2A represents the standby condition of the needle 15, while Fig. 2B represents the working condition of the needle 15 wherein the film 1 3a is broken at the center position thereof. When the film 13a is broken at the center position thereof, the gas contained in the space formed by the cylindrical space 4a and the space between the valve 4 and the cap 13 escapes through the brokened aperture of the film 13a, and consequently, the gas pressure in this space is instantly lowered. Accordingly, the valve 4 is displaced from its interrupt position toward the cap 13 and the conduit 2a is connected to the conduit 3.

When the fire extinguishing gas is supplied into the bomb 2, before assembling the necessary elements of each fire extinguisher, a gas supply conduit (not shown) is firstly thread engaged with the T shaped head portion of the conduit 2a while the other end of the T shaped head portion is sealed with the cap 13. Then the fireextinguishing gas of high pressure is supplied via the gas supply conduit. In this condition, the valve 4 is displaced to the position adjacent to the cap 13 so that the gas supply conduit is connected to the conduit 2a. After the bomb 2 is filled with the fire-extingusihing gas, the gas supply is stopped.Since there is a very small cylindrical clearance between the peripheral surface of the valve 4 and the inside wall of the T shaped head portion, the space formed by the cylindrical space 4a and the space between the valve and the cap 13 is gradually filled with the gas and the gas pressure in the above-mentioned space becomes the same as that of the bomb 2. In this condition, the valve 4 is automaticaly displaced toward the ring shaped wall formed between the thin cylindrical portion and the thick cylindrical portion of the T shaped head portion 2b, and finally, the valve 4 is urged against the above-mentioned ring shaped wall so that the T shaped head portion 2b is completely sealed by the valve 4.

The internal pressure detecting switch 5 comprises a bellows (not shown) always connected to the conduit 2a as shown in Fig. 2A. Therefore when the bomb 2 is filled with the fire-extinguishing gas, the bellows is axially expanded in accordance with the gas pressure. A limit switch (not shown) is disposed at a position adjacent to the bellows in such a condition that the limit switch normally closes a circuit when the bellows is axially expanded, and the above-mentioned circuit is opened and another circuit is closed when the axial deformation of the bellows is eliminated.

The above-mentioned condition of elimination of the axial deformation of the bellows corresponds to the gas ejection from the bomb 2.

The control circuit of the automatic fireextinguishing system shown in Fig. 1 is hereinafter explained in detail with reference to the circuit diagram shown in Fig. 3.

The control circuit of each fire extinguisher is identical as shown in Fig. 3. Therefore this control circuit is hereinafter referred to as a unit control circuit 11. The unit control circuit 11 comprises: a magnetic relay 17, provided with an on-off switch 17a; a timer relay 18 which is also a magnetic relay provided with an on-off switch 18a; an electric circuit 16a of a solenoid (not shown) of the electro-mechanical means for opening the valve 4, an electric circuit 19 of a limit switch (not shown) of the gas jet detecting switch 6, and; a limit switch 20 of the internal pressure detecting switch 5.

The unit control circuit 11 is connected to an intermediate power source 8 compris ing a transformer 8a and rectifier 8b. A terminal of the magnetic relay 17 and a terminal of the timer relay 18 are connected to a ground Le which is connected to one terminal of the rectifier 8b. The other terminal of the relays 17 and 18 are conected to an input terminal Ila of the unit control circuit 11 in parallel condi tion. One terminal of the on-off switch 1 7a is connected to the ground LG, while the other terminal of the switch 17a is connected to an input terminal of the electric circuit 16a of the solenoid of the electro-mechanical means for opening the valve 4.The limit switch 19 is provided with three terminals 19a, l9b and 19c and the output terminal of the electric circuit 16a is connected to the terminal 19c of the limit switch 19. The terminal 19a is connected to the terminal l9c when the gas pressure in the conduit 3 is low, that is, when the fire-extinguishing gas is not issued. When the fire-extinguishing gas is issued and the gas pressure in the conduit 3 or in the nozzle 7 becomes higher than a predetermined gas pressure, the terminal 19a is connected to the terminal 19b.Therefore, when the fireextinguishing gas in the bomb 2 is fully exhausted, since the gas pressure in the conduit 3 becomes low again, the terminal 19a is therefore connected to the terminal l9c. The output terminal 19a of the limit switch 19 is connected to the input terminal 20b of the limit switch 20, while the output terminal 20a is connected to the line L2.

The limit switch 20 is operated in response to the gas pressure in the bomb 2 in such a way that the terminal 20a is connected to the terminal 20b when the gas pressure in the bomb 2 is increased and the terminal 20a is disconnected from the terminal 20b when the gas pressure in the bomb 2 is decreased. The terminal 19b is connected to an output terminal 1 1b of the unit control circuit 11. The line L2 disposed in the unit control circuit 11 is provided with a power input terminal 11 d and a power output terminal llc, and the on-off switch 18a is utilized so as to be able to connect the line L to an output terminal llb. This on-off switch 18a is actuated by the timer relay 18.

In the automatic fire-extinguishing system shown in Fig. 1, the fire sensors 9 are electrically connected in a series and, referring to Fig. 3 again, the input terminal thereof is connected to the line L2 by way of a line L,, while the output ter minal thereof is connected to the input terminal 1 la of the control circuit of the first fire extinguisher No. 1.The unit control circuit 11 of the fire extinguisher No. 2 is connected to the unit control circuit 11 of the fire extinguisher No. 1 in such a way that the input terminal 1 la of the fire extinguisher No. 2 is connected to the output terminal 1 ib of the fire extinguisher No. 1, while the power input terminal 11 d of the line L2 of the fire extinguisher No. 2 is connected to the power output terminal 1 1c of the line L2 of the fire extingiusher No. 1.

The connection of the unit control circuits 11 of two adjacent fire extinguishers are made in the same way as the abovementioned connection of the unit control circuits of the fire-extinguishers No. 1 and No. 2. Therefore, in a case of utilizing a large number of fire-extinguishers for the automatic fire-extinguishing system according to the present invention, the assembled control circuit for controlling the func tional operation of the fire-extinguishers can be made very simply.

The functional operation of the automatic fire-extinguishing system shown in Figs. 1 and 3 will now be explained in detail. When any of the fire sensors 9 detects a fire, the line L is connected to the line L1 so that the sensing signal is applied to the input terminal 1 la of the unit control circuit 11 of the fire-extinguisher No. 1. Consequently, the magnetic relay 17 is actuated to close the switch 17a. When the internal pressure of the bomb 2 is so high that the switch 5 is not actuated, that is, when the internal pressure is under a normal condition, the electric circuit 1 6a of the solenoid of the electro-mechanical means for opening the valve 4 is energized, so that the solenoid is actuated and inserts the needle 15 into the film 13a (Figs. 2A, 2B).Accordingly, the film 13a is broken so that the gas contained in the space formed by the cylindrical space 4a and the space between the valve 4 and the cap 13 escapes therefrom, and the valve 4 is displaced toward the cap 13. When the valve 4 is displaced as mentioned above, the conduit 3 is connected to the conduit 2a so that the fire-extinguishing gas is ejected from the nozzle 7 of the fire-extinguisher No. 1.

Consequently, the gas presusre in the conduit 3 is remarkably increased so that, at first, the bellows of the gas jet detecting switch 6 are axially expanded. Accordingly, the connection between the terminals 19a and 19c of the limit switch 19 is opened so that electric power being supplied to the electric circuit 16a is stopped. At the same time, the termmal 19a is connected to the terminal 19c. At this time, since the fire extinguisher No. 1 has just started to jet the fire-extinguishing gas, the gas pressure in the bomb 2 is sufflicently high so that the terminal 20a is maintained in contact with the terminal 20b.Consesequently, the line Lye is connected to the output terminal lib via the limit switches 19 and 20, and electric power is transmitted to the input terminal lia of the unit control circuit 11 of the fire extinguisher No.

2 via the output terminal lib of the unit control circuit of the fire extinguisher No.

1. Consequently, the fire extinguisher No.

2 is actuated to eject the fire-extinguishing gas from the nozzle 7 thereof in the same manner as mentioned above. The fire extinguishers No. 3, No. 4 and so on, are actuated so as to eject the fire-extinguishing gas from their own nozzles 7 one by one in succession, as mentioned above.

When the fire-extinguishing gas is fully exhausted, since the gas pressure in the bomb 2 and in the conduit 3 is remarkably lowered, the terminal l9a is connected to the terminal 19c and, at the same time, the terminal 20a is disconnected from the terminal 20b. Therefore, although the terminal 19a is connected to the terminal 19c again after the fire-extinguishing gas has been fully exhausted, no electric power is supplied to the electric circuit 16a.

When the internal pressure of the bomb begins to be lowered by the gas leakage, at first, the switch 5 is actuated prior to the operation of the switch 6. Consequently, since the terminal 19a is disconnected from the terminal lid, even if gas presusre in the bomb is further lowered to actuate the switch 6, electric power is not transmitted to the next fire extinguisher No. 2 by the gas leakage. Accordingly, the abovementioned possible problem due to gas leakage from the bomb 2 can be correctly prevented.

In the case where the switch 5 and or the switch 6 is actuated by the gas leakage, when a signal issued from any of the fire sensors 9 is applied to the terminal gila, the relay 17 and the timer relay 18 are actuated at the same time. Therefore, although the switch 17a is closed, the electric circuit 16a is not energized because the switch 5 and/or the switch 6 is actuated.

However, the timer relay 18 is actuated after a predetermined time. As a result of this, the switch 18a is closed so that electric power is transmitted to the input terminal I la of the subsequent fire extinguisher. As understood from the foregoing explanation, at this stage, the valve 4 of the bomb 2 of the fire extinguisher No. 1 is not actuated by the application of a signal from the sensors 9.

In the above-mentioned automatic fireextinguishing system, if the relay 17 of the unit control circuit of some fire extingiusher does not work, the fire extinguishers arranged at electrically downstream positions can not work. For example, if the relay 17 of the fire extinguisher No. 1 does not work, since it is impossible to energise the electric circuit 1 6a of the solenoid, the unit control circuit of the fire extinguisher No. 2 can not receive the electrical actuation signal from the unit control circuit of the fire extinguisher No. 1. Therefore, the remaining fire extingiushers No. 2, No. 3, and so on, can not work. To prevent such a problem, the timer relay 18 is utilized in the unit control circuit of each fire extinguisher.

That is, when an actuation signal is transmitted to the timer relay 18, the timer relay 18 is actuated to close the on-off switch 1 8a after a predetermined time after the signal is transmitted thereto. Therefore, even if the magnet relay 17 does not close the one-off switch 17a, the unit control circuit of the fire extinguisher No. 2 receives power from the line L2 via the one-off switch 18a and the terminals llb of the unit control circuit of the fire extinguisher No. 1. Accordingly the fire extinguishers, arranged at electrically downstream positions from the fire extingiusher wherein the magnet relay 17 does not work, can be perfectly operated.

As mentioned above, the fireextinguishers of the automatic fire-extinguishing system shown in Fig. 4 are actuated so as to eject the fire-extinguishing gas from their own nozzle 7 one by one successively, and; the capacity of the intermediate power supply source can be reduced to a great extent from that required for the prior arts for example reduced to only a capacity sufficient to work the sensors 9 and a single unit control circuit of a fire extinguisher.

As already pointed out, this is one of the advantages of the automatic fire-extinguishing system according to the present invention.

In addition, another embodiment of the automatic fire-extinguishing system according to the present invention is shown in Fig. 4. The embodment shown in Fig. 4 differs from the embodiment shown in Fig.

3 in that the internal pressure detecting switch 5 having the limit switch 20 is omitted therefrom and another type of limit switch 19' is used, which is controlled by the above-mentioned gas jet detecting switch 6. The limit switch 19' is also provided with three terminals 19'a, 19'b, and 19'c. During the initial stage, the terminal 19'a is connected to the terminal 19'c.

When the gas pressure in the conduit 3 becomes high again, the terminal 19'a is disconnected from the terminal 19'c, connected to the terminal 191z, and maintained in contact with the terminal 19'b.

That is, once the terminal 19'a is connected to the termmal 19'b due to the increase of the gas pressure in the conduit 3, this connection therebetween is maintained even if the gas pressure in the conduit 3 is lowered due to gas exhaustion.

The functional operation of the automatic fire-extinguishing system shown in Fig. 4 will now be explained in detail. When anyone of the fire sensors 9 detects a fire, the Ine L0 is connected to the line L1 so that the sensing signal is input to the unit control circuit of the fire-extinguisher No. 1.

Consequently, the magnet relay 17 is actuated to close the switch 17a. When the switch 17a is closed, the electric circuit 16a of the solenoid of the electro-mechanical means for opening the valve 4 is energized, so that the solenoid is actuated and inserts the needle 15 into the film 13a (Figs. 2A 2B). Accordingly, the film 13a is broken so that the gas contained in the space formed by the cylindrical space 4a and the space between the valve 4 and the cap 13 escapes therefrom, and the valve 4 is displaced toward the cap 13. When the valve 4 is displaced as mentiond above, the conduit 3 is connected to the conduit 2a so that the fire-extinguishing gas is ejected from the nozzle 7 of the fire extinguisher No. 1. Consequently, the gas pressure in the conduit 3 becomes remarkably high so that the bellows of the switch 6 are axially extended.Accordingly, the connection between the terminals 19'a and l9'c of the limit switch 19' is opened and the terminal 19'b is connected to the terminal 19'a of the limit switch 19' of the fire extinguisher No. 1. Therefore, electric power is transmitted to the line La of the unit control circuit 11 of the fire extingiusher No. 2 via the output terminal 1 lib of the unit control circuit 11 of the fire extinguisher No. 1 and the input terminal 1 1a of the unit control circuit 11 of the fire extinguisher No. 2. Consequently, the fire extinguisher No. 2 is actuated to eject the fire-extinguishing gas from the nozzle 7 thereof in the same manner as mentioned above.The fire-extinguishers No. 3, No. 4 and so on, are actuated so as to eject the fire-extinguishing gas from their own nozzles 7, one by one in succession, as mentioned above. Since the connection between the terminals 19'a and 19'b is maintained even if the gas pressure in the conduit 3 is lowered, electric power is not wasted in the electric circuit 16a after the valve 4 is opened.

As the operation of the timer relay 18 is the same as that of the circuit shown in Fig. 3, an explanation about the operation of the timer relay 18 will not be included herein.

WHAT WE CLAIM IS: - 1. An automatic fire-extinguishing system comprising a plurality of portable fireextinguishers, each fire-extinguisher including a pressure vessel containing a fire extinguishing gas under pressure and a gas discharge nozzle connected through a valve to said vessel, at least one fire sensor, and a main controller for opening a plurality of the valves in response to a fire signal from the fire sensor or sensors; wherein the main cotroller is associated with one of the fire-extinguishers and comprises electromechanical means actuatable in response to the fire signal to open the valve of the associated fire extinguisher which thereafter remains open, and gas discharge detecting means responsive to gas discharge from the vessel to the nozzle to terminate actuation of said electro-mechanical means and generate a slave fire signal, the or each of the other fire-extinguishers having slave controllers, connected to one another in successive series from the main controller of said one fire-extinguisher, the or each of the slave controllers having respective said electro-mechanical means and gas discharge detecting means and being responsive to generation of the slave fire signal by the preceding controller of the series to actuate its electro-mechanical means.

2. An automatic fire-extinguishing system as claimed in claim 1 wherein the controller and the or each slave controller

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. omitted therefrom and another type of limit switch 19' is used, which is controlled by the above-mentioned gas jet detecting switch 6. The limit switch 19' is also provided with three terminals 19'a, 19'b, and 19'c. During the initial stage, the terminal 19'a is connected to the terminal 19'c. When the gas pressure in the conduit 3 becomes high again, the terminal 19'a is disconnected from the terminal 19'c, connected to the terminal 191z, and maintained in contact with the terminal 19'b. That is, once the terminal 19'a is connected to the termmal 19'b due to the increase of the gas pressure in the conduit 3, this connection therebetween is maintained even if the gas pressure in the conduit 3 is lowered due to gas exhaustion. The functional operation of the automatic fire-extinguishing system shown in Fig. 4 will now be explained in detail. When anyone of the fire sensors 9 detects a fire, the Ine L0 is connected to the line L1 so that the sensing signal is input to the unit control circuit of the fire-extinguisher No. 1. Consequently, the magnet relay 17 is actuated to close the switch 17a. When the switch 17a is closed, the electric circuit 16a of the solenoid of the electro-mechanical means for opening the valve 4 is energized, so that the solenoid is actuated and inserts the needle 15 into the film 13a (Figs. 2A 2B). Accordingly, the film 13a is broken so that the gas contained in the space formed by the cylindrical space 4a and the space between the valve 4 and the cap 13 escapes therefrom, and the valve 4 is displaced toward the cap 13. When the valve 4 is displaced as mentiond above, the conduit 3 is connected to the conduit 2a so that the fire-extinguishing gas is ejected from the nozzle 7 of the fire extinguisher No. 1. Consequently, the gas pressure in the conduit 3 becomes remarkably high so that the bellows of the switch 6 are axially extended.Accordingly, the connection between the terminals 19'a and l9'c of the limit switch 19' is opened and the terminal 19'b is connected to the terminal 19'a of the limit switch 19' of the fire extinguisher No. 1. Therefore, electric power is transmitted to the line La of the unit control circuit 11 of the fire extingiusher No. 2 via the output terminal 1 lib of the unit control circuit 11 of the fire extinguisher No. 1 and the input terminal 1 1a of the unit control circuit 11 of the fire extinguisher No. 2. Consequently, the fire extinguisher No. 2 is actuated to eject the fire-extinguishing gas from the nozzle 7 thereof in the same manner as mentioned above.The fire-extinguishers No. 3, No. 4 and so on, are actuated so as to eject the fire-extinguishing gas from their own nozzles 7, one by one in succession, as mentioned above. Since the connection between the terminals 19'a and 19'b is maintained even if the gas pressure in the conduit 3 is lowered, electric power is not wasted in the electric circuit 16a after the valve 4 is opened. As the operation of the timer relay 18 is the same as that of the circuit shown in Fig. 3, an explanation about the operation of the timer relay 18 will not be included herein. WHAT WE CLAIM IS: -

1. An automatic fire-extinguishing system comprising a plurality of portable fireextinguishers, each fire-extinguisher including a pressure vessel containing a fire extinguishing gas under pressure and a gas discharge nozzle connected through a valve to said vessel, at least one fire sensor, and a main controller for opening a plurality of the valves in response to a fire signal from the fire sensor or sensors; wherein the main cotroller is associated with one of the fire-extinguishers and comprises electromechanical means actuatable in response to the fire signal to open the valve of the associated fire extinguisher which thereafter remains open, and gas discharge detecting means responsive to gas discharge from the vessel to the nozzle to terminate actuation of said electro-mechanical means and generate a slave fire signal, the or each of the other fire-extinguishers having slave controllers, connected to one another in successive series from the main controller of said one fire-extinguisher, the or each of the slave controllers having respective said electro-mechanical means and gas discharge detecting means and being responsive to generation of the slave fire signal by the preceding controller of the series to actuate its electro-mechanical means.

includes a relay which is activated in response to the fire signal (or slave fire signal as the case may be) to actuate said associated electro-mechanical means.

3. An automatic fire-extinguishing system as claimed in claim 1 or claim 2 wherein said main controller includes power supply means for all the controllers.

4. An automatic flre-extinguishing system as claimed in any preceding claim wherein each of the controllers (main and slave) includes a timer relay arranged to generate said slave fire signal a predetermined time delay after receiving a fire signal or slave fire signal as the case may be.

5. An automatic fire-extinguishing system substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.