EP1534394B1

EP1534394B1 - Automatic foam fire fighting equipment especially used as fixed installation equipment for fire fighting of large hydrocarbon storage tanks

Info

Publication number: EP1534394B1
Application number: EP02793261A
Authority: EP
Inventors: Istvan Szöcs
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-04-17
Filing date: 2002-12-30
Publication date: 2006-08-30
Anticipated expiration: 2022-12-30
Also published as: HU225884B1; DE60214442D1; CN1627972A; ATE337831T1; SI1534394T1; CN100540092C; DE60214442T2; EA006175B1; JP2005530526A; HUP0201260A2; WO2003086546A1; AU2002358919A1; HU0201260D0; EA200401387A1; UA78781C2; EP1534394A1

Abstract

The automatic foam fire fighting equipment according to the invention has a tank, means for spreading fire extinguishing foam, pipeline and a main valve situated in the pipeline, and a detector, and its characteristic feature is that its tank is a foam tank (15) storing an overcompressed mixture of foam-forming compound, water, and foam generating and driving gas dissoluble or emulsive in the solution of the foam-forming compound and the water, which tank has a gas space (16), the means for spreading fire extinguishing foam is expanding nozzle (20, 22), further, its detector consists of at least two pneumatic detectors (31, 32; 35, 36) arranged to detect inflammation independently from each other in essentially the similar way, and the main valve (18) situated in the pipeline (17) connecting the foam tank (15) with the expanding nozzle (20, 22) is of pneumatic type, where the two pneumatic detectors (31, 32; 35, 36) monitoring the same area are in common controlling arrangement with each other, and they are in direct or indirect pneumatic controlling connection with the main valve (18), providing opening control signal to the main valve (18) in case of detecting fire.

Description

The object of the invention is automatic foam fire fighting equipment which, due to its construction, needs neither energy nor water from external source for starting and maintaining its operation, and, secondly, it is protected against false starting, and therefore it can be used especially as fixed installation equipment for fire fighting of storage tanks of flammable liquids, particularly liquid hydrocarbon. The fire fighting equipment according to the invention has a tank, means for spreading the fire extinguishing foam, pipeline, a main valve situated in the pipeline, and a detector.
It is well known that when a liquid hydrocarbon storage tank is catching fire, there is only a very short time between the ignition and the inflammation of the surface of the liquid stored in the tank, e.g. in case of petrol it is only a few seconds. Further, when the fire has developed, a significant amount, e.g. in case of petrol, a 7 mm thick layer is burned from the surface each minute. In order to avoid significant environment pollution and pecuniary loss due to the burning of large amount of hydrocarbon it is desirable that the fire fighting equipments installed at storage tanks should start operation automatically and quickly, and for this, the fire must be detected at high reliability, the fire extinguishing foam must be supplied immediately, and the foam must be quickly flooded on the burning surface.
US-A-4148361 discloses a storage tank used to store petroleum products, said tank being provided with a foam delivery system comprising a foam supply, foam discharge means, a foam delivery conduit connecting said supply with said discharge means, and a main valve placed in said conduit.
Other known foam fire fighting equipments installed at liquid hydrocarbon storage tanks comprise a tank for storing foam-forming compound concentrate, a separate fire-water network or separate water tank for obtaining water, a mixing device for producing foam solution, foam generating devices, means for spreading the fire extinguishing foam, a pipeline network connecting these elements, one or several pumps suitable for forwarding water and/or foam solution, and stop-valves in the pipeline. Further, the equipments comprise an electric motor or combustion engine driving the pump or pumps and an external power source to supply these motors, and a detector bringing the equipment into operation, situated at a specified point of the storage tank. The detector applied may be mechanic, pneumatic, hydraulic, electrical or electronic type. The pneumatic detector is of plastic pipe type or sprinkler head type, and is filled with overcompressed gas, especially air, and in most cases it is provided with a baroswitch.
The prior art fire fighting equipments provided with pneumatic detector operate in a way that in case of fire the gas in the detector expands due to the generated heat, its pressure increases, or due to the destruction of the detector the pressure drops, and as a result of the change in the pressure a baroswitch sends an electric signal, which electric signal, or an electric signal derived from this signal starts the operation of the equipment by switching the pump on and starting the flow of water this way. The flowing water is first mixed with the foam-forming compound and forms foam solution, the foam solution flowing on in the pipeline network is mixed with air in the foam generating device and forms fire extinguishing foam, and the ready fire extinguishing foam obtained this way, which has obtained its final volume, is conducted to the surface of the liquid burning in the tank through pourers of the required cross section or through foam chambers.
These equipments have the deficiency that if there is a change in the pressure in the detector due to failure, e.g. due to damage in the course of maintenance works, mounting error, defects in material, ageing, or overheating due to sunshine etc., the detector sends false signal, and starts the operation of the fire fighting equipment just as if there were fire. The fire fighting apparatus automatically started by the false signal of the detector is permanently producing and spreading the fire extinguishing foam into the storage tank until it is stopped, that is, until it is proven that the signal sent by the detector was false. This foam is practically wasted, which is significant loss in itself. There are further additional losses such as the energy consumption, water consumption, and the re-filling of the fire fighting equipment with foam-forming compound. Further, the foam, as contamination, must be removed from the surface of the liquid hydrocarbon, and the storage tank must be withdrawn from production for the time of the examination and/or reconstruction, which results in further significant loss. A further deficiency is that the fire fighting team is alerted in vain, which also has certain expenses.
It is a further deficiency of these equipments that for their operation there is a need for external energy source and a pump operated using this energy source, and therefore the operability of the equipments depend on the actual status of the energy source and the pump, which is a potential source of error as well.
At the known constructions, efforts are made to eliminate this deficiency by establishing and maintaining network parts specially for fire fighting purposes, e.g. by establishing and maintaining a separate electric network besides the separate fire water network or separate fire water tank, used exclusively for operating the fire fighting equipment, and/or by keeping a spare pump etc. in ready-to-use status. Establishing and maintaining a separate energy source is an expensive investment, and also, it does not provide such operational reliability that must be required in case of automatic fire fighting equipments. Because even if there is a separate electric network, e.g. in case of an explosion that usually accompanies tank fires or in case of electric conduit fire, it may occur that due to disturbance in the electric network the fire fighting equipment is unserviceable just in the critical moment, or it starts operation with delay.
The above disadvantages made it necessary to develop an automatic foam fire fighting equipment that is reliable in starting its operation and which is of high operational reliability, and which has a construction that prevents the equipment from false starting.
The basic concept of the invention is that the above disadvantages can be eliminated by a foam fire fighting equipment where the energy required for generating the fire extinguishing foam and for starting and maintaining the operation of the equipment can be easily stored. Therefore the fundamental idea of the invention is that besides the gaseous medium used for generating the fire extinguishing foam and acting as a constituent of the fire extinguishing foam, the detectors must be chosen to be pneumatic type detectors, the controlling means must be of pneumatic type, and the energy required for generating and getting out the fire extinguishing foam must be stored in the equipment acting as an energy storing system, in the form of overcompressed non-inflammable gaseous medium in ready-to-use status.
Therefore the automatic foam fire fighting equipment according to the invention, which can be especially used as fixed installation equipment for fire fighting of liquid hydrocarbon storage tanks, has a tank, means for spreading fire extinguishing foam, pipeline and a main valve situated in the pipeline, and a detector. The characteristic feature of the fire fighting equipment is that its tank is a foam tank storing an overcompressed mixture of foam-forming compound, water, and foam generating and driving gas dissoluble or emulsive in the solution of the foam-forming compound and the water, which tank has a gas space, the means for spreading fire extinguishing foam is an expanding nozzle, further, its detector consists of at least two pneumatic detectors arranged to detect inflammation independently from each other in essentially the similar way, and the main valve situated in the pipeline connecting the foam tank with the expanding nozzle is of pneumatic type, where the two pneumatic detectors monitoring the same area are in common controlling arrangement with each other, and they are in direct or indirect pneumatic controlling connection with the main valve, providing opening control signal to the main valve in case of detection of a fire by two detectors from the same area.
At a preferable embodiment of the equipment the foam generating gas and the driving gas is one kind of gas, preferably carbon dioxide.
At another preferable embodiment of the equipment the foam generating gas and the driving gas is a mixture of gases, preferably a mixture containing carbon dioxide.
The volume of the foam tank of the fire fighting equipment according to the invention is determined by the amount of the foam-forming compound and water corresponding to the amount of fire extinguishing foam to be generated plus the overcompressed foam generating and driving gas or gas mixture dissoluble or emulsive in that. The tank is designed to be chemically resistant against the foam-making compound and the foam generating and the driving gas, and it is pressure resistant. Inside the tank there is a gas space, the volume of which is not less than 8 % of the volume of the tank, and in the regular state of the tank there is only gas phase material in the gas space. The tank is supplied with suitably positioned priming means - pipe stubs, valves etc. - for supplying the fire extinguishing foam components, and it is also equipped with a pressure gauge.
The expanding nozzle used for spreading the fire extinguishing foam can be of conventional design, or it can be so called continuous linear nozzle with or without pressure-compensating chamber or pressure-compensating tank.
The pipeline connecting the foam tank with the expanding nozzle is made of material of the required strength with a diameter chosen according to the amount of foam to be transmitted under the required pressure, and the pipeline is connected to the part of the foam tank where the liquid phase is stored.
The main valve situated in the pipeline is preferably a two position router pneumatically controllable or a butterfly gate controlled by pneumatic operating working cylinders.
The construction of the pneumatic detectors of the fire fighting equipment according to the invention is known in itself. The pneumatic detectors are filled with gaseous medium with pressure above the atmospheric pressure, e.g. with air, suitably with the driving and/or the foam generating gas. Under heat the detecting element of the detectors is distorted, and thereby the pressure of the gas inside drops to the atmospheric pressure. Such pneumatic detectors can be plastic pipe linear detectors where the plastic pipe filled with overcompressed gas is splitting under heat, or can also be the type with sprinkler heads mounted on a metal pipe where the detecting element of one or several sprinkler heads mounted on the metal pipeline filled with overcompressed gas is deformed under heat.
At a preferable embodiment of the fire fighting equipment the two pneumatic detectors arranged to detect inflammation independently from each other in essentially the similar way are fashioned so that they can be fixed running around the inner side of the wall of the tank near its rim at a predetermined distance from each other. This way the two detectors are in essentially similar position relative the surface of the liquid in the tank, so they can detect the inflammation of the surface of the liquid at practically the same place and at the same time, and they can provide signals about the fire separately, independently from each other.
At the fire fighting equipment according to the invention, the common controlling arrangement of the two pneumatic detectors monitoring the same area, and their pneumatic controlling connection with the main valve can be achieved in different ways. It can be achieved either by establishing logic AND connection between the two detectors, or by connecting the two detectors to the inputs of a pneumatic logic AND element, where the output signal of the pneumatic logic AND element is the signal controlling the main valve.
It is a very favourable embodiment of the fire fighting equipment which has a pneumatic control unit, where the pneumatic detectors are connected to the inputs of the pneumatic control unit, and the control input of the main valve is connected to the output of the pneumatic control unit, which control unit is constructed so that in case if signals indicating ignition are arriving to its inputs connected to the two pneumatic detectors monitoring the same area, it provides control signal at its output with the command to open the main valve.
At a preferred embodiment of the fire fighting equipment according to the invention developed for monitoring several areas (e.g. in case of a storage tank with a guarding ring these areas can be the inner area of the tank and the area between the guarding ring and the tank), the pneumatic control unit has several pneumatic logic AND elements and a pneumatic logic OR element connected to the output of the logic AND elements. The inputs of the pneumatic logic AND elements - suitably through shaping elements - constitute the inputs of the pneumatic control unit receiving the detectors monitoring the same area, e.g. the inner area of the tank or the area of the guarding ring, while the output of the pneumatic logic OR element - suitably through a shaping element - constitutes the output of the pneumatic control unit connected to the control input of the main valve.
At an embodiment of the fire fighting equipment according to the invention the pneumatic power supply of the pneumatic detectors and the pneumatic elements is the gas space of the foam tank.
At another preferable embodiment the pneumatic detectors and the pneumatic elements have a pneumatic power supply unit including a gas cylinder assembled with a pressure stabilizer, which can be an independent pneumatic power supply unit or can be connected in parallel with the gas space of the foam tank. The working substance of the power supply can be the foam generating gas and/or the driving gas or a mixture of gases containing these, or can be some inactive gas e.g. nitrogen.
The essence of the automatic foam fire fighting equipment according to the invention is now described in more detail by presenting a preferable embodiment, with reference to the accompanying schematic drawing where:

Figure 1. shows the schematic structure of a fire fighting equipment installed as fixed installation on a storage tank provided with guarding ring, also showing the schematic diagram of its operating pneumatic system.

Figure 1. shows the schematic structure of a fire fighting equipment, at this example installed on a petrol storage tank 10 built with a guarding ring 12. The tank with the guarding ring has two monitored areas at this example, one is the inner area of the storage tank 10, the other is the area between the storage tank 10 and the guarding ring 12.
The fire fighting equipment has a foam tank 15, expanding nozzles 20 and 22, and a foam pipeline 17 connecting the foam tank 15 with the expanding nozzles 20 and 22, which pipeline 17 is connected to the lower space of the foam tank 15. There is a pneumatic two-position two-way router inserted into the pipeline 17, acting as a main valve 18.
The expanding nozzle 20 is circularly mounted on the inner side of the wall of the storage tank 10 near its upper rim, as it can be seen at the broken-out section of the storage tank 10, and its slot is directed towards the wall of the tank. Similarly, the expanding nozzle 22 is circularly mounted on the inner side of the wall near the upper rim of the guarding ring 12 of the storage tank 10, and, as it can be seen at the broken-out section of the expanding nozzle 22 in the broken out section of the guarding ring 12, its slot 23 is directed towards the wall.
The fire fighting equipment has two plastic pipe type pneumatic detectors 31 and 32, which pneumatic detectors 31 and 32 are mounted in the inner space of the storage tank 10 near its rim under the expanding nozzle 20, running around the side of the wall of the tank 10 one below the other at a predetermined distance from each other. Also, it has two further plastic pipe type pneumatic detectors 35 and 36, which pneumatic detectors 35 and 36 are mounted in the inner space of the guarding ring 12 near the rim, under the expanding nozzle 22, running around the inner side of the wall one below the other at a predetermined distance from each other, which can be seen in the figure in a broken out manner in the broken out section of the guarding ring 12.
This way the two detectors 31 and 32 in the storage tank 10 are in essentially similar position relative to the surface of the liquid, so they can detect the inflammation of the surface of the liquid at practically the same way, and they can provide signals about it separately, independently from each other. Likewise, the two detectors 35 and 36 in the guarding ring 12 are in essentially similar position relative to the surface of the liquid, so they can detect the inflammation of the surface of the liquid at practically the same way, and they can provide signals about it separately, independently from each other.
The fire fighting equipment has a pneumatic control unit 40, and the pneumatic detectors 31, 32, and 35, 36 are connected to the inputs of the pneumatic control unit 40 through separate pneumatic conduits 33, 34, and 37, 38. The output of the pneumatic control unit 40 is connected to the control input of the pneumatic two-way two-position router acting as a main valve 18 through a pneumatic control conduit 45.
The pneumatic control unit 40 has two pneumatic elements 61 and 63 realizing logic AND operation, and a pneumatic element 65 realizing logic OR operation connected to the output of the two pneumatic elements 61 and 63. Pneumatic detectors 31 and 32 located in the inner space of the storage tank 10 are connected to the inputs of the first pneumatic element 61 through signal shaping elements 56 and 57 via conduits 33 and 34. Pneumatic detectors 35 and 36 located in the inner space of the guarding ring 12 are connected to the inputs of the second pneumatic element 63 through signal shaping elements 58 and 59 via conduits 37 and 38. The output of the pneumatic element 65 passes through a signal shaping element 67 and forms the output of the pneumatic control unit 40.
The pneumatic power supply of the presented fire fighting equipment is the gas space 16 of the foam tank 15, which gas space 16 is connected to the supply input of the pneumatic control unit 40 by supply conduit 41, and to the supply input of the pneumatic two-position two-way router acting as the main valve 18 by supply conduit 43.
Each input of the pneumatic control unit 40 of the fire fighting equipment is connected to its supply input through separate pneumatic choke elements 51, 52, 53 and 54.
Before operating the fire fighting equipment, the foam tank 15 is filled through its appropriate openings with the water solution of the foam-forming compound and the overcompressed foam generating gas and driving gas dissoluble and/or emulsive in the solution, preferably carbon dioxide which is suitable for both purposes, while the main valve 18 and the further safety valves situated in the conduits, not shown in the figure, are in closed position. Further, from the gas space 16 of the foam tank 15, through the supply conduit 41 and the pneumatic control unit 40 the plastic pipe type pneumatic detectors 31, 32, 35 and 36 are filled with pressurized gas, and through the supply conduit 43 and the pneumatic control unit 40 the main valve 18 is set in prestressed closed position.
Thereupon the equipment is ready for operation.
The operation of the equipment is started if the pressure either in both pneumatic detectors 31, 32 on the storage tank 10 or in both pneumatic detectors 35, 36 on the guarding ring 12 changes in the sense that indicates fire, at this example the plastic tube of the detectors splits due to overtemperature, and therefore the pressure in the detector drops to the atmospheric pressure.
The pressure dropped to the atmospheric pressure is transmitted by conduits 33 and 34 and/or 37 and 38 to the input of the signal shaping element 56 and 57 and/or 58 and 59 connected to the corresponding input of the pneumatic control unit 40. As a result, the output signal of one or both signal shaping element pairs changes. As a result of the simultaneous change of its two input signals in the same sense, the pneumatic element 61 connected to the output of the signal shaping elements 56 and 57 and/or the pneumatic element 63 connected to the output of the signal shaping elements 58 and 59, sends output signal indicating fire to one or both inputs of the pneumatic element 65. Accordingly, through a pneumatic control conduit 45 connected to the output of the pneumatic control unit 40 with the signal shaping element 67 inserted, the pneumatic element 65 sets the pneumatic two-way two-position router acting as a main valve 18 into open position.
In the open position of the main valve 18, the overpressure in the foam tank 15 presses out the compressed fire extinguishing foam comprising a mixture of the foam-forming compound and water and the foam generating gas dissolved in it from the foam tank 15, and, passing through the foam pipeline 17, the compressed fire extinguishing foam gets into the expanding nozzle 20 and/or 22. When the compressed fire extinguishing foam is discharged through the slot of the expanding nozzles 20, 22 to the atmospheric pressure in the inner space of the storage tank 10 and/or the guarding ring 12, the overcompressed foam generating gas dissolved in the solution blows up the foam, which takes the volume corresponding to the atmospheric pressure, this way the foam solution is transformed into a foam stream. Thus, the generation of the fire extinguishing foam is finished at the very place and time of its application.
The expanding nozzle 20, 22 emits the fire extinguishing foam along the wall of the tank or the guarding ring, and the foam flows down the wall to the surface of the liquid, cooling the wall on the one hand, and providing an insulating layer on the wall preventing it from the flames and heat on the other. When the foam is reaching the surface of the burning liquid, it drifts on it and, moving from the wall of the tank or the guarding ring to the centre of the surface of the liquid, it gradually covers the surface. Due to the permanent supply of foam, the foam is gradually closing and reducing the burning free surface of the liquid, while the surface already covered is separated from the flames. The foam floating on the surface of the liquid closes in the centre, or, in case of a floating-roof tank or a tank with guarding ring, it reaches the foam barrier or the wall of the tank and closes to it, and this way, by covering the free surface of the liquid, it isolates oxygen from the burning surface and extinguishes the fire.
One implemented fire fighting equipment extinguished stabilized fire at an experimental tank surface of 500 m² in 30 seconds.
Choke elements 51, 52, 53, 54 ensure that the pressure drop in the pneumatic detectors effect the pressure of the gas space acting as a pneumatic power supply only with delay and to an acceptable degree.
The protection of the fire fighting equipment according to the invention against false starting is ensured by the construction that the pneumatic control unit 40 sends a signal indicating fire only in case if in both pneumatic detectors 31 and 32 installed in the storage tank 10 or in both pneumatic detectors 35 and 36 installed in the guarding ring 12 the pressure changes in a sense that indicates fire.
If the pressure changes only in one pneumatic detector in the storage tank 10 or in the guarding ring 12, or if the pressure changes in two pneumatic detectors installed at different places, the control unit 40 will not assume it as a signal indicating fire, and will not send a control signal indicating fire.
The fire fighting equipment can also be constructed in a way that the expanding nozzle 20 in the storage tank 10 is connected to the foam tank 15 with a separate main valve, and the expanding nozzle 22 in the guarding ring 12 is also connected to the foam tank 15 with an other main valve. The control unit 40 of such an equipment opens only one main valve or the other main valve or both main valves feeding the corresponding expanding nozzle, depending on the signal received from the pneumatic detectors, and therefore only the tank, or only the guarding ring, or both are flooded with foam.
A simple embodiment of the fire fighting equipment according to the invention has only two pneumatic detectors installed on the tank. At this embodiment the control unit 40 sends a control signal to open the main valve if the pressure changes in both pneumatic detectors in a sense that indicates fire.
The fire fighting equipment according to the invention can also be constructed to have a separate pneumatic power supply unit which unit comprises a gas cylinder assembled with a pressure stabilizer, where the gas cylinder is filled with the applied foam generating and driving gas or with suitable indifferent gas in relation to the applied foam generating and driving gas and the environment. It is an especially safe and reliable embodiment of the equipment where the pneumatic power supply unit comprising the gas cylinder assembled with the pressure stabilizer is a parallel combination of the gas space 16 of the foam tank 15.
The major advantage of the fire fighting equipment according to the invention is that all the energy required for its operation, that is, for opening its main valve, generating the fire extinguishing foam and carrying it from the tank to the place of application, is stored in the form of pressure energy since the overcompressed foam generating and/or driving gas is filled into the foam tank of the equipment and the overpressure is maintained in the tank. Therefore the fire fighting equipment can be kept in ready-to-use status and automatically operated at any time, irrespective of the existence and serviceability of any other network, e.g. electric network, drainage network, fuel tank, and of the status of the pump.
The other major advantage of the equipment according to the invention is that its detectors are pneumatic detectors, so if the supply pressure is present, the detectors are always ready for operation and operate automatically. As in case of fire the information carrying output signal of the detectors is pneumatic signal, preferably a drop in the pressure of the detectors from the supply pressure to the atmospheric pressure, one working substance is eligible for the operation of the equipment, and this working substance can preferably be chosen to be the foam generating and/or the driving gas under pressure, so in this case it is the working substance storing the energy necessary for the operation of the equipment and the working substance forwarding the information carrying signal necessary for the operation of the equipment at the same time. It is a further advantage that by organising the detectors into logic connections, the equipment is practically insensitive to false detector signals.
Adjusted to the actual needs, the fire fighting equipment according to the invention can be implemented to be installed at any size of fuel tank by positioning the pneumatic detectors according to the actual needs, organising the pneumatic detectors into several logic connections according to the actual needs, in certain cases organising a pneumatic detector into several connections, and using one or several pneumatic control units controlling main valves in pipes supplying separate expanding nozzles.
The fire fighting equipment according to the invention can also be used as automatic fixed installation fire fighting equipment protecting several storage tanks independently from each other.
The fire fighting equipment according to the invention can be especially used as fixed installation equipment for fire fighting of storage tanks storing liquid hydrocarbons such as petrol, kerosene, oil etc, or other flammable liquids e.g. alcohol or other solvents, but it can also be used at other places as automatic fixed installation foam fire fighting equipment, e.g. at warehouses storing flammable material etc.

Claims

Automatic foam fire fighting equipment, to be especially used as fixed installation equipment for fire fighting of liquid hydrocarbon storage tanks, having a tank, means for spreading fire extinguishing foam, a pipeline and a main valve situated in the pipeline, and a detector,
characterized in that its tank is a foam tank (15) storing an overcompressed mixture of foam-forming compound, water, and foam generating and driving gas dissoluble or emulsive in the solution of the foam-forming compound and the water, which tank has a gas space (16), the means for spreading fire extinguishing foam is expanding nozzle (20, 22), further, its detector consists of at least two pneumatic detectors (31, 32; 35, 36) arranged to detect inflammation independently from each other in essentially the similar way, and the main valve (18) situated in the pipeline (17) connecting the foam tank (15) with the expanding nozzle (20, 22) is of pneumatic type, where the two pneumatic detectors (31, 32; 35, 36) monitoring the same area are in common controlling arrangement with each other, and they are in direct or indirect pneumatic controlling connection with the main valve (18), providing opening control signal to the main valve (18) in case of detection of a fire by two detectors from the same area.
Fire fighting equipment according to claim 1.
characterized in that the foam generating gas and the driving gas is one kind of gas, preferably carbon dioxide.
Fire fighting equipment according to claim 1.
characterized in that the foam generating gas and the driving gas is a mixture of gases, preferably a mixture containing carbon dioxide.
Fire fighting equipment according to any of claims 1-3
characterized in that the pneumatic detectors (31, 32; 35, 36) are linear detectors or detectors comprising sprinkler heads mounted on a metal pipeline.
Fire fighting equipment according to any of claims 1-4
characterized in that the pneumatic detectors (31, 32; 35, 36) are fashioned so that they can be mounted running around the inner side of the wall of the tank near the rim of the tank at a predetermined distance from each other.
Fire fighting equipment according to any of claims 1-5
characterized in that it has a pneumatic control unit (40), where the pneumatic detectors (31, 32; 35, 36) are connected to the inputs of the pneumatic control unit (40), and the control input of the main valve (18) is connected to the output of the pneumatic control unit (40), which control unit (40) is constructed so that in case if signals indicating ignition are arriving to its inputs connected to the two pneumatic detectors (31, 32; 35, 36) monitoring the same area, it provides control signal at its output with the command to open the main valve (18).
Fire fighting equipment according to any of claims 1-5
characterized in that the pneumatic control unit (40) has several pneumatic logic AND elements (61, 63) and a pneumatic logic OR element (65) connected to the output of the logic AND elements (61, 63), and the inputs of the pneumatic logic AND elements (61, 63), suitably through shaping elements (56, 57, 58, 59), constitute the inputs of the pneumatic control unit (40) receiving the detectors (31, 32; 35, 36) monitoring the same area, e.g. the inner area of the tank or the area of the guarding ring, while the output of the pneumatic logic OR element (65), suitably through a shaping element (67), constitutes the output of the pneumatic control unit (40) connected to the control input of the main valve (18).
Fire fighting equipment according to any of claims 1-7
characterized in that the pneumatic power supply of the pneumatic detectors (31, 32; 35, 36) and the pneumatic elements is the gas space (16) of the foam tank (15).
Fire fighting equipment according to any of claims 1-8
characterized in that the pneumatic detectors (31, 32; 35, 36) and the pneumatic elements have a pneumatic power supply unit which comprises a gas cylinder assembled with pressure stabilizer.