Fire-extinguishing system

FIELD OF INVENTION

The invention relates to a fire-extinguishing system according to the preamble of claim 1.

PRIOR ART

Fires cause great economic losses annually in residential, commercial and industrial buildings. For extinguishing fires, particularly in commercial and industrial buildings are generally used different sprinkler systems in which extinguishing liquid is distributed centralised by means of a pipe system and nozzles to spaces to be extinguished. Installing conventional sprinkler systems particularly in old buildings is a laborious and expensive operation. Furthermore, there are several such targets in commercial and industrial buildings in which extending the sprinkler system is not justifiable, hi these spaces, there still can exist devices susceptible to fire, whereby also these spaces would require some kind of a fire- extinguishing system.

Fire detectors and power switch-off devices utilised in residential buildings improve fire safety but they are not intended for extinguishing fires. In residential buildings, there can be portable fire extinguishers installed on walls or in fire cabinets which are intended for use by able persons still in the building during a fire. The extinguishing medium volume of such portable fire extinguishers is usually in the range of 2.5—10 1 and pressures in the range of 5-20 bar are used in them.

hi restaurants and particularly in residential buildings, a cooker is one site from which fires easily start. Cooker fires are the most common cause of electric fires

and fire fatalities in residential buildings. A cooker fire can start e.g. from grease on the cooker or from grease or foodstuffs collected in filters above the cooker or from flammable material beside the cooker. In dwellings, cooker fires are focused on persons having reduced abilities, such as elderly persons.

An effective way to reduce fire fatalities is to install automatic extinguishing systems in hazardous spaces. It is advantageous in preventing fire fatalities that extinguishing occurs automatically when a fire is detected in the space.

JP patent specification 7132151 describes an automatic fire-extinguishing device for a kitchen gas cooker. The device comprises a control unit, an extinguishing medium unit installed in a cupboard at the side of a cooker hood, provided with a pressure valve, an extinguishing nozzle installed in the cooker hood, a piping between the extinguishing medium unit and the extinguishing nozzle, a sensor in- stalled into connection with the extinguishing nozzle in the cooker hood for detecting a cooker fire, a solenoid valve cutting off the supply of gas, and a warning device in connection with the control unit. Furthermore, there is additionally a pressure switch in the extinguishing medium unit, which triggers a warning signal if pressure decreases below a specified value in a pressure tank of the extinguish- ing medium unit. If the sensor in the cooker hood detects an abnormal fire, the control unit controls the solenoid valve to shut off the supply of gas, controls the warning device to give a warning, and opens the pressure valve of the extinguishing medium unit for conveying extinguishing medium to the extinguishing nozzle and further to the cooker.

WO specification 92/12912 describes an arrangement for using aerosols and aerosol packages. Each aerosol package comprises a pressure-resistant outer shell, being the shape of a cylinder, and a resilient, baggy inner container inside the outer shell. In an outwards curvilinear cover of the cylindrical outer shell, a pres- sure valve is fitted by means of which the baggy inner container can be filled and emptied. In an inwards curvilinear bottom of the cylindrical outer shell, an open-

ing is formed from which a space between the outer shell and the baggy inner container can be filled with propellant gas. The propellant gas compresses the baggy inner container tightly. After filling with the propellant gas, the opening at the bottom is closed. After this, the baggy inner container is filled via the pressure valve with fire- extinguishing medium, whereby the pressure of the propellant gas between the outer shell and the inner container increases as its volume decreases. The propellant gas stays in all situations in the closed space between the outer shell and the inner container and is not in contact with the fire-extinguishing medium, whereby the aerosol package is reusable after being refilled with extin- guishing medium. Such an aerosol package operates in any position.

SUMMARY OF INVENTION

The object of the invention is a cost-effective as well as easily installable and maintainable automatic fire-extinguishing system.

The principal characteristic features of the fire-extinguishing system according to the invention are presented in the characterising part of claim 1.

Other additional features of the invention are presented in the dependent claims.

The fire-extinguishing system according to the invention constitutes an independent and automatic extinguishing system. The system can be described as an automatic foam extinguisher which possibly first warns and, if the user does not react to the warning, extinguishes the fire or extinguishes the fire totally automatically without warnings. The fire-extinguishing system does not require a water fitting as sprinkler systems do and the system can be provided with its own power supply, whereby the system becomes totally independently operating.

The fire-extinguishing system according to the invention is compact and it can be constituted as its own partition-like, movable unit which can be used e.g. in the

fire watch of hot works. Again, the fire-extinguishing system according to the invention can be integrated into any target or unit to be protected or in a structure such as e.g. the ceiling structures or wall structures of the space to be protected, in a cooker hood, into connection with a welding device etc.

The structure of the fire-extinguishing system according to the invention is modular, whereby it can be easily accommodated in accordance with the volume of extinguishing medium required by each target and the usable installation space.

The fire-extinguishing system according to the invention improves e.g. the fire safety of cookers considerably and it is able to extinguish cooker fires irrespective of the abilities of the resident. The system can be maintained at regular intervals by changing the extinguishing medium packages contained by it. The system is also suitable for difficult grease fires and its use is cost-effective during its whole lifetime. The system is easy and cheap to install, maintain and inspect and, furthermore, work required after extinguishing is minor in comparison with many conventional arrangements.

The extinguishing medium package described in the above WO specification 92/12912 is well suitable for use as the extinguishing medium package in the fire- extinguishing system according to the invention. A fire-extinguishing system provided with such extinguishing medium packages operates in any position.

BRIEF DESCRIPTION OF FIGURES

Fig. 1 shows a schematic block diagram of a fire-extinguishing system according to the invention.

Fig. 2 shows a schematic view of an extinguishing medium package suitable for the fire-extinguishing system according to the invention.

Fig. 3 shows a schematic view of a power switch-off device suitable for the fire- extinguishing system according to the invention.

Fig. 4 shows a schematic view of another power switch-off device suitable for the fire-extinguishing system according to the invention.

Fig. 5 shows a schematic view of a fire-extinguishing system according to the invention in connection with an electric cooker.

Fig. 6 shows a schematic view of an alternative trigger mechanism suitable for the fire-extinguishing system according to the invention.

Fig. 7 shows a schematic side view of another alternative trigger mechanism suitable for the fire- extinguishing system according to the invention.

Fig. 8 shows a schematic top plan view of the trigger mechanism shown in Fig. 7.

DESCRIPTION OF ADVANTAGEOUS EMBODIMENTS

Fig. 1 shows a schematic block diagram of a fire-extinguishing system 100 according to the invention. The fire-extinguishing system 100 comprises two extinguishing medium units A, B connected in parallel such that, in the upper, first extinguishing medium unit A, there are two extinguishing medium packages 120, 130 and, in the lower, second extinguishing medium unit B, there is one extin- guishing medium package 140. The fire-extinguishing system 100 further comprises a conveying channel system 150, 151, 152, 153 of extinguishing medium, in which there is a connecting channel 150 whereby each extinguishing medium package 120, 130, 140 is in connection via a first feed channel 151, 152, 153 and which connecting channel 150 is in connection with an extinguishing nozzle 210, a trigger mechanism 160, 170, 180 for each extinguishing medium package which comprises a trigger bar 161, 171, 181 and an actuator 162, 172, 182 controlling

the trigger bar 161, 171, 181 which actuator consists of a temperature-sensitive trigger cord 162, 172, 182. The fire-extinguishing system 100 further comprises a control unit 190 and a switching device 110 coupled to the control unit 190, a power supply 200, a sensor 220, a wireless data transmission unit 195, and a user interface 230 which includes a warning device 232 and a sound source 231. Furthermore, the fire-extinguishing system 100 is connected to a power switch-off device 240.

Fig. 2 shows a schematic view of an extinguishing medium package 120 suitable for the fire-extinguishing system 100 according to the invention which is known as such from the above WO specification 92/12912. The extinguishing medium package 120 comprises a cylinder-shaped outer shell 121 in which there are a cover 121a and a bottom 121b. Inside the outer shell 121 is fitted a baggy, flexible and gas-proof inner part 123. A space 122 between the outer shell 121 and the inner part 123 is filled with propellant gas and an inner space 124 of the inner part 123 receives fire-extinguishing medium. In the cover 121a of the outer shell 121 is fitted a valve structure 125 in which the inner part 123 is sealingly joined. In the valve structure 125, there is a nozzle 126 from which the inner part 123 can be filled with fire-extinguishing medium and from which the fire-extinguishing me- dium in the inner part 123 can be conveyed out. Compressing the nozzle 126 inwards, e.g. by means of a collar 128 surrounding the nozzle, triggers a pressure valve 127 in the valve structure 125. The propellant gas is totally isolated from the fire-extinguishing medium in the inner space 124 of the inner part 123, whereby there is no connection between the inner space 124 of the inner part 123 and the space 122 filled with propellant gas. As the pressure valve 127, it is possible to use any valve known by those skilled in the art such as e.g. a spring-loaded ball valve. The extinguishing medium package 120 used in the invention does not include the bottom opening described in WO specification 92/12912 but the propellant gas is brought inside the outer shell 121 from the opening of the valve struc- ture 125 of the cover 121 a of the outer shell 121.

The trigger system of the extinguishing medium packages 120, 130, 140 shown in Fig. 1 is implemented in the following way. An outer end of the nozzle 126, 136, 146 of each extinguishing medium package 120, 130, 140 is led through an opening in each trigger bar 161, 171, 181 so that flanges 128 on the outer surface of the nozzles 126, 136, 146 set against the trigger bar 161, 171, 181. Moving the trigger bar 161, 171, 181 by means of the trigger cord 162, 172, 182 compresses the nozzles 126, 136, 146 inwards via the collars 128, whereby the pressure valve 127 of each extinguishing medium package 120, 130, 140 opens and extinguishing medium flows from the inner part 124 of each extinguishing medium package 120, 130, 140 into the first feed channel 151, 152, 153 and from there further via the connecting channel 150 to the extinguishing nozzle 210 from which it discharges into the target on fire. The trigger cords 162, 172, 182 are of temperature- sensitive cord, e.g. cord marketed with the trade name Flexinol which shrinks in the longitudinal direction in a specified temperature range. For the trigger cords 162, 172, 182, power can be connected from the power supply 200 with the switching device 110 controlled by the control unit 190, whereby power heats the thin trigger cords 162, 172, 182 very quickly into the desired temperature. When the temperature of the trigger cords 162, 172, 182 increases as a result of the power passing in them, the trigger cords 162, 172, 182 shrink in the longitudinal direction and transfer the trigger bar 161, 171, 181 so that the trigger bar 161, 171,

181 turns into a trigger position. The trigger cord 162, 172, 182 also performs a kind of an auxiliary triggering in a situation in which fire causes an increase in the temperature of the trigger cord 162, 172, 182 without the trigger cord 162, 172,

182 having been heated with electricity.

In principle, the operation of the fire-extinguishing system 100 shown in Fig. 1 is the following. The control unit 190 detects based on signals sent by the sensor 220 that a fire has possibly started. The control unit 190 controls the warning device 232 in the user interface 230 to give a warning which can be visual or based on sound. The user can acknowledge the warning from the user interface 230, whereby the system continues monitoring the situation and possibly cuts off the

supply of power from the fire site. If cutting off the power does not correct the situation but the control unit 190 detects that the fire continues or escalates, the control unit 190 controls the switching device 110 to switch on power in the trigger cords 162, 172, 182. As a result of heat caused by the power, the trigger cords 162, 172, 182 shrink in the longitudinal direction and transfer the trigger bars 161, 171, 181 in the trigger position, whereby the pressure valves 127 open and fire- extinguishing medium discharges from the nozzles 126, 136, 146 to the conveying channel system 150, 151, 151, 152 and from there forward to the extinguishing nozzle 210 from which it discharges to the fire site. The user interface 230 and the warning device 232 are not necessarily required in a situation in which the fire- extinguishing unit 100 is located in an unoccupied space. Extinguishing the fire occurs then totally automatically as a result of a deduction chain programmed in the control unit 190.

Fig. 3 shows a schematic view of a fire-extinguishing system 100 according to the invention in connection with an electric cooker 10. The fire-extinguishing system 100 is located in a cooker hood 20 above the cooker 10. The cooker hood 20 can solely consist of a hood, whereby an extractor fan on the roof of the building sucks air via a discharge flue 21 and the cooker hood 20 to the roof of the build- ing. The cooker hood 20 can also include its own fan, whereby the fan pushes air either to the discharge flue 21 or via an active carbon filter back to the space in which the cooker 10 is. On the lower edge of the cooker hood 20, there are visible the extinguishing nozzle 210 and the sensor 220 monitoring the state of the cooker 10. The user interface 230 of the fire-extinguishing system 100 can be located e.g. on a front wall 22 of the cooker hood 20.

When the sensor 220 of the fire-extinguishing system 100 detects an unusual increase of temperature caused by a fire load 11 and/or the forming of flue gas 12, it transmits this information forward to the control unit 190 which controls the warning device 232 in the user interface 230 to warn about the fire e.g. by a sound signal and/or warning light. If the user does not acknowledge the warning from

the user interface 230 in a specified time, the control unit 190 of the fire- extinguishing system 100 controls the sound source 231 in the user interface 230 to give a sound signal to the power switch-off device 240 connected to the operating power supply of the cooker 10 for cutting off the operating power of the cooker 10. After the signal, the control unit 190 of the fire-extinguishing system 100 continues monitoring the sensor data 220 and, if status information received from the environment continues its negative development, such as increasing of flue gases 12 and/or rising of temperature, the control unit 190 controls the warning device 232 in the user interface 230 to give a warning to the user of a fire risk e.g. by a sound signal and/or warning light. If the user does not acknowledge the warning given by the warning device 232 in a specified time, the trigger mechanism 160, 170, 180 of the fire-extinguishing system 100 triggers the extinguishing medium from the extinguishing medium packages 120, 130, 140 of extinguishing medium to the conveying channel system 150, 151, 152, 153 and from there fur- ther via the extinguishing nozzle 210 to the target. If required, the fire- extinguishing system 100 can be set from the user interface 230 to a non- active, so-called flaming mode for a specified time, after which the fire-extinguishing system 100 returns to a normal mode. In the flaming mode, which lasts for a specified time, the control unit 190 changes the warning and/or triggering values to such that changes of the status information of the environment occurring in connection with cooking do not activate the warning and/or triggering.

The maintenance and inspection of the fire-extinguishing system 100 can be done by removing the grease filter of the cooker hood 20, whereby there is an access from the opening of the grease filter to the fire-extinguishing system 100. In scheduled maintenance and in a maintenance situation after triggering, the extinguishing medium packages 120, 130, 140 are replaced in the fire-extinguishing system 100. After replacing the extinguishing medium packages 120, 130, 140, the fire-extinguishing system 100 is again operational.

Fig. 4 shows a schematic view of a power switch-off device 240 suitable for the fire-extinguishing system according to the invention, by means of which it is possible to cut off the power supply of the target e.g. an electric cooker. The control unit 190 controls in a fire situation the sound source 231 in the user interface 230 to give a sound signal. In the power switch-off device 240, there is a trigger device 241 connected to a microphone. When the trigger device 241 receives the sound signal produced by the sound source 231, a relay 242 controls voltage Ll to a contactor 243 which cuts off the supply of electricity Ll, L2, L3 coming to the target from the network. The switch-off device 240 and the sound source 231 can be implemented e.g. by a product marketed by the company Innohome with the trade name Liesivahti.

Fig. 5 shows a schematic view of another power switch-off device 240 suitable for the fire-extinguishing system according to the invention, by means of which it is possible to cut off the gas supply of the target e.g. a gas cooker. The control unit 190 controls in a fire situation the sound source 231 in the user interface 230 to give a sound signal. When the trigger device 241 receives the sound signal produced by the sound source 231, the relay 242 controls voltage L to a solenoid valve 245 which cuts off the supply of gas G coming to the target from the net- work.

Fig. 6 shows a schematic view of an alternative trigger mechanism 300 suitable for the fire-extinguishing system according to the invention. The trigger mechanism 300 comprises a body part 310 which is fastened in a collar part of the valve structure 125 of the extinguishing medium package 120 by a band 320. In the body part 310 around the outer end of the nozzle 126 of the extinguishing medium package 120 is fitted a spring 330 the inner end of which supports itself against the flange 128 being around the nozzle 126 and the outer end supports itself against a fixed upper part 340 of the body part 310. The flange 128 of the nozzle 126 is supported from its lower surface against a force caused by the spring 330 by means of a rocker arm 350. The rocker arm 350 is supported from a pivot point

351 in the middle part of the rocker arm 350 pivotedly to the body part 310. A first end 352 of the rocker arm 350 constitutes a support surface for the flange 128 and at the other end of the rocker arm 350 there is a hole 353 from which the rocker arm 350 is fastened to the trigger cord 162 which is located in a pipe 360. The shrinking of the trigger cord 162 in the longitudinal direction rotates the rocker arm around the pivot point clockwise M, whereby the support surface of the first end 352 of the rocker arm 350 turns away from the flange 128. The spring 330 loading the flange 128 then compresses the nozzle 126 inwards and opens the pressure valve 127 in the valve structure 125. The trigger mechanism 300 is here integrated as a part of the extinguishing medium package 120.

Fig. 7 shows a schematic side view of another alternative trigger mechanism 400 suitable for the fire-extinguishing system according to the invention and Fig. 8 shows a schematic top plan view of the trigger mechanism 400 shown in Fig. 7. The trigger mechanism 400 comprises a body part 410 which is fastened in a collar part of the valve structure 125 of the extinguishing medium package 120 by a band 420. A rocker arm 430 is pivotedly 440 supported from its first bifurcated end to the body part 410. In the middle part of the rocker arm 430, there is an opening 431 from which the outer end of the nozzle 126 protrudes. The rocker arm 430 leans from its middle part against the flange 128 around the nozzle 126. The trigger cord 162 is fastened at the other end of the rocker arm 430 and the trigger cord 162 passes aside the extinguishing medium package 120 inside a pipe 450. The shrinking of the trigger cord 162 in the longitudinal direction rotates the rocker arm 430 around the pivot point 440 in a direction shown by arrow M, whereby the other end of the rocker arm 430 compresses against the body part 410. The middle part of the rocker arm 430 being against the flange 128 then compresses the nozzle 128 inwards via the flange 128 and opens the pressure valve 127 in the valve structure 125. The trigger mechanism 400 is here integrated as a part of the extinguishing medium package 120.

In the fire-extinguishing system 100 shown in Fig. 1, there are thus two extinguishing medium units A, B connected in parallel. In the upper, first extinguishing medium unit A, there are two extinguishing medium packages 120, 130 connected in parallel and, in the lower, second extinguishing medium unit B, there is one extinguishing medium package 140. It is also possible to consider that there are three extinguishing medium units connected in parallel, in which in each there is one extinguishing medium package 120, 130, 140. In the fire-extinguishing system according to the invention, there are at least two extinguishing medium units connected in parallel such that in each extinguishing medium unit there is at least one extinguishing medium package.

In a situation in which the fire-extinguishing system 100 shown in Fig. 1 functions as the fire-extinguishing system of a cooker, there can be used e.g. extinguishing medium packages 120, 130, 140 containing about 0.533 1 of extinguishing me- dium, whereby the total volume of the extinguishing medium is about 1.6 1. This volume of extinguishing medium is well enough for extinguishing normal cooker fires in dwellings. The fire-extinguishing system 100 requires then a space being about 40 cm wide, about 30 cm deep and about 10 cm high. Such a fire- extinguishing system is easily integratable in a cooker hood. The pressure of the extinguishing medium package 120, 130, 140 is about 6 bar when the inner space 124 of the package inner part 123 is full of extinguishing medium.

The fire-extinguishing system 100 shown in Fig. 1 is, due to its modular structure, easily arrangable in many kinds of targets. The number and size of the extinguish- ing medium units A, B and extinguishing medium packages 120, 130, 140 in them can be increased in accordance with the required volume of extinguishing medium and the space usable. In the fire-extinguishing system 100, it is possible to use its own power source 200, such as an accumulator or batteries, whereby the fire- extinguishing system 100 becomes a system totally independent of other external systems.

The fire-extinguishing system 100 shown in Fig. 1 can also be provided with a wireless data transmission unit 195 connected to the control unit 190. The wireless data transmission unit 195 can solely comprise a transmitter or there can be both a transmitter and a receiver. By means of the wireless data transmission unit 195, it is possible e.g. to transmit warning information indicating a fire to a mobile phone or to some other equivalent wireless communication device.

In the fire-extinguishing system 100 shown in Fig. 1, from each nozzle 126, 136, 146 of the extinguishing medium package 120, 130, 140 leads its own first feed channel 151, 152, 153 of extinguishing medium to the common connecting channel 150 of extinguishing medium which is in connection with the extinguishing nozzle 210 from which the extinguishing medium discharges to the fire site. Instead of one extinguishing nozzle 210, the fire-extinguishing system 100 can utilise several extinguishing nozzles and single extinguishing medium packages 120, 130, 140 can be connected in a desired way to these extinguishing nozzles. In the fire-extinguishing system shown in Fig. 1, it is e.g. possible to use at least two separate extinguishing nozzles which are connected to the connecting channel 150. It is also possible to divide the connecting channel 150 into two different connecting channels, whereby e.g. the extinguishing medium package 120, 130 of the first extinguishing medium unit A were connected to a first connecting channel and the extinguishing medium package 140 of the second extinguishing medium unit B were connected to a second connecting channel. It would then be possible to connect in each connecting channel one or more extinguishing nozzles. The feed channel system 150, 151, 152, 153 of extinguishing medium can thus, within the scope of the invention, be implemented in accordance with conditions and requirements prevailing in each target of use.

In the fire-extinguishing system 100 shown in Fig. 1, there is in each extinguishing medium package 120, 130, 140 its own separate trigger mechanism 160, 170, 180. By using their own trigger mechanism 160, 170, 180 in each extinguishing medium package 120, 130, 140, the extinguishing medium packages 120, 130,

140 can be located freely in accordance with free spaces in the target. Additionally, trigger reliability is maximised, because one trigger mechanism of the extinguishing medium package 120, 130, 140 giving out does not affect the operation of the trigger mechanism of the other extinguishing medium packages 120, 130, 140. The fire-extinguishing system 100 according to the invention can also be implemented so that two or even all extinguishing medium packages 120, 130, 140 have one common trigger mechanism.

The fire-extinguishing system 100 shown in Fig. 1 utilises trigger bars 161, 171, 181 and actuators 162, 172, 182 connected to them i.e. a trigger cord 162, 172, 182 for performing the triggering of the pressure valves 127 of the extinguishing medium packages 120, 130, 140. As the actuator 162, 172, 182 instead of the trigger cord 162, 172, 182, it is naturally possible to use e.g. a servo motor or a cylinder or some other equivalent actuator by means of which the trigger bar 161, 171, 181 can be moved. The trigger bar 161, 171, 181 can be pivotedly fastened in the support structure, whereby the trigger bar 161, 171, 181 is moved around the pivot point.

In the fire-extinguishing system 100 shown in Fig. 1 , there is one common switch- ing device 110 by means of which power is switched on the trigger cords 162, 172, 182. For each trigger cord 162, 172, 182, it is also possible to arrange its own switching device 110, if required.

The parts of the fire-extinguishing system 100 shown in Fig. 1 can in principle be located freely and supported on suitable support structures in the target to be protected. Each extinguishing medium package 120, 130, 140 and the trigger mechanism 160, 170, 180 connected to it constitute one unity.

In the fire-extinguishing system 100 shown in Fig. 1, the warning device 232 and the sound source 231 are integrated into the user interface 230, but the warning device 232 and the sound source 231 can also consist of separate devices.

The fire-extinguishing system 100 according to the invention can be implemented simplified such that there are no user interface 230, warning device 232, sound source 231, power switch-off device 240 and wireless data transmission unit 195 shown in Fig. 1. Such a simplified implementation is suitable e.g. for a situation in which the fire-extinguishing system is installed in a space where no people normally go. Also the power supply 200 can be omitted, whereby the power supply required by the system is supplied from the electric power network in the space to be protected.

The use of the power switch-off devices 240 shown in Figs. 4 and 5 does not require any cabling between the user interface 230 of the fire-extinguishing system 100 and the switch-off device 240, because the trigger command transmits from the sound source 231 to the switch-off device 240 based on a sound signal passing in the air. This is extremely convenient e.g. in a situation in which the extinguishing system 100 is used in connection with the cooker 10. The power switch-off device 240 can be located as its own unit instead of an access box of the cooker 10 at the back of the cooker close to the floor. A cable connection awkwardly im- plementable as retrofitting between the switch-off device 240 and the user inter- face 230 is not required.

Above were described only some advantageous embodiments of the invention and it is evident to those skilled in the art that several modifications can be made to them within the scope of the enclosed claims.