RU2752438C1 - Nitrogen fire extinguishing system for special structure - Google Patents

Abstract

FIELD: gas fire extinguishing systems.SUBSTANCE: invention relates to gas fire extinguishing systems and can be used, for example, in enclosed spaces and underground structures, in particular underground special fortifications (SF). In the event of a fire in one (or several) of the rooms 2 and the appearance of smoke, a fire detector 10 located in this room 2 is triggered, and a signal is sent from it to the control unit 12. From the control unit 12, the control signal is sent to the actuator of the shut-off valve 9 of the corresponding distribution line 8 for the supply of compressed nitrogen. This control signal gives the command to open the shut-off valves 9 of the distribution line 8. After that, the compressor 15 is started and the flue gases from the burning room 2 are sucked into the corresponding flue gas outlet line 16 at the level of the ceiling surface and then enter the intermediate flue gas tank 13, from where, with the help of the compressor 15, they are removed from the special fortification 1 through the shaft 4 into the environment along the smoke-removal line 14. The location of the gas ejector 17 at the end of each distribution line 8 makes it possible to use flue gases formed as a result of combustion as an additional source of neutral gas to reduce the concentration of oxygen and increase the extinguishing rate by intensifying the volume of extinguishing gas due to the use of a mixture of nitrogen and flue gases sucked from the internal volume of the room 2, where the fire occurred, through the passive gas pipeline 18 from the upper part of the room 2.EFFECT: increased safety of operation of the nitrogen fire extinguishing system and the speed of fire extinguishing, reduced nitrogen consumption for extinguishing fire foci, as well as the possibility of purging the internal volume of an isolated room after extinguishing the fire.1 cl, 1 dwg

Description

The invention relates to gas fire extinguishing systems and can be used, for example, in enclosed spaces and underground structures, in particular, underground special fortifications (SPS).

It is known to arrange special fortifications that are built deep underground to accommodate command posts, communication centers, shelters for especially important military equipment and ammunition, medical institutions, etc. Special fortifications can be multi-storey and include: main premises, entrance galleries with solid entrance caps, equipped with protective doors or gates, ventilation and technological openings with protective devices. The internal equipment of special fortifications includes technological systems (communications, electronic devices) and technical systems: filtration, heating, cooling, lighting, air conditioning, autonomous power supply, water supply, sewerage, fire extinguishing, etc. (Levykin V.I.

Known is the device of a special underground fortification, in which communication with the day surface is carried out along a vertical shaft adjacent to the wall of the structure. These entrances are called mine entrances (Lapshin G.A. -96).

There is a method of volumetric fire extinguishing, including storage of liquid freon, its transportation, supply to the room and inhibition of the combustion reaction with freon vapors, and a device containing a container with liquid freon, a compressed gas cylinder for displacing freon, a pipeline for transporting freon and sprayers for supplying freon in the room (Fighting fires on ships. Edited by MG Stavitsky. L. Shipbuilding, 1976, pp. 185-190).

The disadvantage of such installations is the harmful effect of freons on the environment, in addition, these installations have rather large mass-dimensional characteristics, which reduces the efficiency of their use for extinguishing fires. The use of freons is limited in closed rooms, since the products of thermal decomposition of freons are highly toxic and highly corrosive. In addition, the implementation of international measures for the protection of the ozone layer of the Earth in accordance with the Montreal Protocol (1987) will require a reduction in the use of the mentioned freons, as substances with high ozone-depleting potential.

Known methods and systems for extinguishing a fire by supplying sprayed water, foam, powder and inert gas to the combustion zone (Fire safety. Explosion safety / Ed. By AN Baratov, M .: "Chemistry", 1987).

However, the known solution of using water, along with the advantages, has a high inertia and can lead to damage to electrical equipment, and when extinguishing a fire in a sealed object, to a dangerous increase in pressure up to an explosion. The use of foam or powder is a highly costly method of fire extinguishing and insufficiently effective due to the small protected area and the impossibility of supplying a fire extinguishing agent to a fire located in a hard-to-reach place. In addition, the fire extinguishing ability of the listed substances under conditions of excess pressure has been little studied. Therefore, these technologies cannot be used in closed specialized premises.

The known method and device for volumetric fire extinguishing, consisting in supplying gas to a room with a flue gas fire (PP Gruzinsky, PM Khokhlov. . 195).

A gas ejector device is known, comprising a housing with pipelines for supplying streams of active and passive gases and with a nozzle for supplying an active gas stream installed in it, a mixing chamber for gas streams and a diffuser communicated with it, while a pipeline for supplying an active gas stream, a nozzle for supplying an active gas stream, a chamber for mixing gas flows and a diffuser are installed along the axis of the ejector, and a passive gas pipeline is connected to the mixing chamber from the side (RF Patent No. 2559115, publ. from 08/10/2015, bull. No. 22).

The principle of operation of a gas ejector is based on the ejection (suction) of a passive gas stream (with a lower pressure) by an active gas stream (a gas with a higher pressure). In this case, the flow of active gas through the pipeline comes from the nozzle of the ejector, and the flow of passive gas through another pipeline enters the space formed by the nozzle and the chamber for mixing gas flows. In this case, the active gas flow is mixed with the passive gas flow in the mixing chamber of the gas flows. The pressure of this gas mixture is equalized and becomes larger in magnitude than the pressure in the passive gas flow. Further, the mixed flow of active and passive gases from the mixing chamber of gas flows enters the diffuser, where there is an increase in static pressure in the mixed gas flow.

A known gas fire extinguishing system based on the use of nitrogen and designed to reduce the oxygen concentration in enclosed spaces to a value of approximately 12% by volume. At these oxygen concentrations, most combustible materials can no longer be ignited. The main areas of application are, in particular, closed industrial premises, premises for switching and distribution of electrical energy, as well as premises in which valuable equipment is located or stored (RF Patent No. 2690062, publ. From 05/30/2019, bull. No. 16).

A known installation of gas fire extinguishing of a special structure with isolated rooms, including means for placing compressed nitrogen, a gas supply line installed in an enclosed space, having distribution units, shut-off valves with drives, fire detectors, oxygen concentration sensors installed in an enclosed space and connected to a control unit, which connected to the drives of shut-off valves and provides regulation of nitrogen supply in an isolated room, depending on the oxygen concentration in the flue gases (USSR author's certificate No. 1151246, publ. of 04/23/1985, bull. No. 15).

The disadvantages of this technical solution are the placement of a source of compressed gas in a place with free access for maintenance personnel, the impossibility of blowing out the internal volume of an isolated room after extinguishing a fire and lighting the room, as well as the need for large volumes of compressed gas to extinguish a fire inside the structure.

The technical result that can be obtained as a result of the implementation of the proposed invention consists in the possibility of increasing the safety of operation of the gas fire extinguishing system, reducing the consumption of nitrogen for extinguishing fires, the possibility of blowing the internal volume of the isolated room after extinguishing the fire, as well as increasing the rate of extinguishing by intensifying the volume of extinguishing gas due to the use of a mixture of nitrogen and flue gases sucked in from the internal volume of the room where the fire broke out.

To achieve this technical result, the proposed nitrogen fire extinguishing system of a special structure, including a compressed nitrogen storage unit located inside the structure, a compressed nitrogen gas supply line, having several distribution lines containing shut-off valves with drives for supplying compressed nitrogen to each isolated room, fire detectors and sensors oxygen concentrations installed in each room, and a control unit that records the indicators of fire detectors and oxygen concentration sensors and is connected to the drives of the shut-off valves of the compressed nitrogen distribution lines to ensure the regulation of nitrogen supply to the premises depending on the oxygen concentration in the flue gases, according to the invention, the system nitrogen fire extinguishing is located inside a special underground fortification, which includes several isolated rooms with opening exits to a common transport tunnel for servicing living personnel, and is equipped with a smoke exhaust pipe with a compressor, located in the mine of an underground special fortification and connecting the special fortification with the earth's surface, and an intermediate flue gas tank connected, on the one hand, with the ground surface, with a smoke exhaust pipe, and, on the other side, with each isolated room with a separate flue gas discharge line, led into the corresponding room at the ceiling level, while the compressed nitrogen storage unit, the control unit and the intermediate flue gas tank are located in a separate isolated room of a special fortification structure, and each distribution line for supplying compressed nitrogen is brought into a corresponding isolated room at the lower level near the floor surface and is equipped at the end with a gas ejector, in which compressed nitrogen is used as an active gas, and flue gases sucked into gases as a passive gas th ejector through the passive gas pipeline from the upper part of the room.

Introduction into the proposed nitrogen fire extinguishing system of a special structure of a smoke exhaust line with a compressor, located in the mine of an underground special fortification and connecting the special fortification with the earth's surface, and an intermediate tank of flue gases connected, on the one hand, with the ground surface by a smoke exhaust line, and , on the other hand, with each isolated room with a separate flue gas discharge line brought into the corresponding room at the ceiling level, the establishment of each distribution line for supplying compressed nitrogen to the corresponding isolated room at the lower level at the floor surface and supplying it at the end with a gas ejector, in which uses compressed nitrogen as an active gas, and flue gases as a passive gas sucked into a gas ejector through a passive gas pipeline from the upper part of the room, as well as the placement of a nitrogen fire extinguishing system inside a sub-zone there is a lot of fortification, which includes several isolated rooms with opening exits to a common transport tunnel for service personnel, while the placement of a compressed nitrogen storage unit, a control unit and an intermediate tank of flue gases in a separate isolated room allows you to obtain a new property consisting in the use of flue gases formed as a result of combustion, as an additional source of neutral gas to reduce the oxygen concentration and extinguish a fire inside a burning isolated room, which provides, on the one hand, a decrease in nitrogen consumption for extinguishing a fire, and on the other hand, an increase in the rate of extinguishing due to the intensification of the volume extinguishing gas due to the use of a mixture of nitrogen and flue gases sucked in from the internal volume of the room where the fire occurred, while simultaneously supplying a mixture of nitrogen and flue gases at floor level and pumping out flue gases at the surface of the ceiling of the insulated about the premises, the possibility of quick blowing of the internal volume of the isolated room after extinguishing the fire due to the effect of the simultaneous flow of air when opening the exit from the common transport tunnel and removing the remaining flue gases through the smoke exhaust pipe into the environment, as well as to increase the reliability and safety of operation of the nitrogen fire extinguishing system for by placing the compressed nitrogen storage unit, the control unit and the intermediate tank of flue gases in a separate isolated room, which, on the one hand, prevents unauthorized personnel access and the destruction of the control unit, and on the other hand, protects the operating personnel from the action of nitrogen emission or flue gases in the event of an emergency depressurization of the nitrogen storage unit or the intermediate tank of flue gases.

FIG. 1 shows a schematic diagram of a nitrogen fire extinguishing system for a special structure.

The nitrogen fire extinguishing system is located inside a special underground fortification 1, which includes several isolated rooms 2 with opening exits 3 to a common transport tunnel 5 for service personnel. Special fortification 1 has a shaft 4 for communication with the earth's surface.

The nitrogen fire extinguishing system includes a compressed nitrogen storage unit 6, a compressed nitrogen gas supply line 7, which has several distribution lines 8 containing shut-off valves 9 with drives for supplying compressed nitrogen to each room 2, fire detectors 10 and oxygen concentration sensors 11 installed in each room 2, and a control unit 12, which registers the signals of fire detectors 10 and oxygen concentration sensors 11 and is connected to the drives of the shut-off valves 9 of the distribution lines of compressed nitrogen 8 and provides regulation of the nitrogen supply to rooms 2 depending on the oxygen concentration in the flue gases.

The nitrogen fire extinguishing system is equipped with an intermediate tank of flue gases 13, connected, on the one hand, with the ground surface by a smoke exhaust pipe 14 with a compressor 15, and, on the other hand, with each isolated room 2 with a separate flue gas discharge line 16, brought into the corresponding room 2 at the level of the ceiling.

The smoke exhaust pipe 13 is located in the shaft 4 of the underground special fortification 1 and connects the special fortification 1 with the surface of the earth.

Compressed nitrogen storage unit 6, control unit 12 and intermediate tank of flue gases 13 are located in a separate isolated room 19 of a special fortification 1 with an opening exit 3 to a common transport tunnel 5 for service personnel.

Each distribution line 8 for supplying compressed nitrogen is led into a corresponding isolated room 2 at the lower level near the floor surface and is equipped at the end with a gas ejector 17, in which compressed nitrogen is used as an active gas, and flue gases sucked into a gas ejector as a passive gas 17 through the passive gas pipeline 18 from the upper part of the room 2.

The work of the proposed system of nitrogen fire extinguishing of a special structure is as follows.

The nitrogen fire extinguishing system of a special structure is designed to extinguish a fire in isolated rooms of underground special fortifications 1. In this regard, the nitrogen fire extinguishing system is located inside an underground fortification 1, which includes several isolated rooms 2 with opening exits 3 to a common transport tunnel 5 for service personnel. Special fortification 1 has a shaft 4 for communication with the earth's surface.

The attendants periodically leave and enter rooms 2 through exits 3 and move between rooms 2 along a common transport tunnel 5, while after the passage of the service personnel, exits 3 are closed and rooms 2 become isolated.

In the event of a fire in one (or more) of rooms 2 and the appearance of smoke, a fire detector 10, located in this room 2, is triggered, and from it the signal is sent to the control unit 12. From the control unit 12, the control signal is sent to the drive of the shut-off valves 9 corresponding distribution line 8 for supplying compressed nitrogen. This control signal gives a command to open the shut-off valve 9 of the distribution line 8.

As a result of opening the shut-off valves 9 of the distribution line 8, compressed nitrogen from the compressed nitrogen storage unit 6 is fed through the compressed nitrogen gas supply line 7 through the distribution line to supply compressed nitrogen 8 to the corresponding room 2 with the fire source, while it is supplied at the lower level at the floor surface through gas ejector 17 located at the end of the distribution line 8. The need to supply nitrogen to the burning room 2 at floor level is explained by the fact that nitrogen is lighter than air, and in this case it will rise from the bottom up, reducing the oxygen concentration.

In the initial period of a fire, it is very important to quickly and safely evacuate service personnel from room 2 with a fire source into a common transport tunnel 5. For this, exit 3 opens and the service personnel leaves room 2 with a fire source. Since nitrogen from the floor level has already begun to be supplied to room 2 with the seat of the fire and a certain back pressure is created, when the outlet 3 is opened, air from the tunnel 5 does not practically enter the burning room 2, which allows not to maintain combustion and provides the necessary time for the evacuation of the service personnel.

After that, the compressor 15 starts up and the flue gases from the burning room 2 at the level of the ceiling surface are sucked into the corresponding flue gas outlet line 16 and then enter the intermediate flue gas tank 13, from where they are removed from the special fortification structure 1 with the help of the compressor 15 through the smoke exhaust line 14 through shaft 4 into the environment.

The location of the gas ejector 17 at the end of each distribution line 8 allows the use of flue gases formed as a result of combustion as an additional source of inert gas to reduce the oxygen concentration and extinguish a fire inside a burning isolated room 2, which, on the one hand, reduces the consumption of nitrogen for extinguishing fire, and on the other hand, an increase in the rate of extinguishing due to the intensification of the volume of extinguishing (neutral gas - a mixture of nitrogen and flue gases) gas due to the use of a mixture of nitrogen and flue gases sucked from the internal volume of room 2, where the fire occurred, through the passive gas pipeline 18 from the upper part of the room 2.

Since the principle of extinguishing a fire with an inert gas - a mixture of nitrogen and flue gases, is based on reducing the oxygen concentration in an isolated burning room 2 to a level of 10-12% in the mixture of air and flue gases, then the simultaneous supply of inert gas at floor level and pumping out flue gases at the surface of the ceiling of a burning room 2 provides a sharp change in the composition of the air mass inside an isolated burning room 2 and a decrease in the oxygen concentration (partial pressure) to levels that exclude the combustion process, thereby increasing the rate of extinguishing a fire inside an isolated burning room 2.

When the oxygen concentration in a closed burning room 2 decreases to a level of 10-12% in the mixture of air and flue gases, the combustion process stops. At the same time, this parameter of the mixture of air and flue gases is recorded by the oxygen concentration sensor 11 in room 2 with the fire site, after which a signal is sent from the oxygen concentration sensor 11 to the control unit 12. From the control unit 12, the control signal is sent to the drive of the shut-off valve 9 of the distribution line 8 supply of compressed nitrogen, which is located in the corresponding room 2 with a fire source. This control signal gives a command to close the shut-off valve 9 of the distribution line 8.

As a result of closing the shut-off valves 9 of the distribution line 8, compressed nitrogen from the storage unit of compressed nitrogen 6 through the gas supply line of compressed nitrogen 7 ceases to be supplied through the corresponding distribution line for supplying compressed nitrogen 8 to room 2 with an extinguished fire.

After extinguishing the fire, in order to ventilate room 2 with the center of an extinguished fire, outlet 3 opens and air from tunnel 5 enters room 2 with compressor 15 still operating, as a result of which the speed of cleaning the internal volume of isolated room 2 from flue gases after stopping combustion and after by removing it along the smoke exhaust line 14 into the environment through the intermediate tank of flue gases 13.

To increase the reliability and safety of operation of the gas fire extinguishing system, the Compressed nitrogen storage unit 6, the control unit 12 and the intermediate tank of flue gases 13 are placed in a separate isolated room 19 with an opening outlet 3, which, on the one hand, prevents unauthorized personnel access and incapacitation. the control unit 12, and on the other hand, protects the operating personnel from the action of the emission of nitrogen or flue gases in the event of an emergency depressurization of the nitrogen storage unit 6 or the intermediate tank of flue gases 13.

Sources of information taken into account when preparing the application:

1. Levykin V.I. Fortification: Past and Present. - M .: Military Publishing, 1987. - p. 101.

2. Lapshin G.A. Special fortifications and their complexes. Textbook for foreign cadets of military higher educational institutions of construction specialties. 1st ed., VI (IT) -SPb. Higher School, 2012. - pp. 95-96.

3. Fighting fires on ships. Ed. M.G. Stavitsky. L. Shipbuilding, 1976, p. 185-190.

4. Fire safety. Explosion safety / Ed. Baratova A.N. M .: "Chemistry", 1987.

5. P.P. Gruzinsky, P.M. Khokhlov. Rescue business and the fight for the survivability of the vessel. M. Transport, 1977, - p. 195.

6. RF patent №2559115, publ. from 08/10/2015, Bul. No. 22.

7. RF patent No. 2690062, publ. from 30.05.2019, Bul. No. 16.

8. USSR author's certificate No. 1151246, publ. from 04/23/1985, Bul. # 15 - prototype.

Claims (1)

A nitrogen fire extinguishing system of a special structure, including a compressed nitrogen storage unit located inside the structure, a compressed nitrogen gas supply line with several distribution lines containing shut-off valves with drives for supplying compressed nitrogen to each isolated room, fire detectors and oxygen concentration sensors installed in each room, and a control unit that records the indicators of fire detectors and oxygen concentration sensors and is connected to the drives of the shut-off valves of the distribution lines of compressed nitrogen to control the supply of nitrogen to the premises depending on the concentration of oxygen in the flue gases, characterized in that the nitrogen fire extinguishing system is located inside the underground a special fortification structure, which includes several isolated rooms with opening exits to a common transport tunnel for service personnel, and is equipped with a smoke exhaust duct alley with a compressor located in the mine of an underground special fortification and connecting a special fortification with the earth's surface, and an intermediate tank of flue gases connected, on the one hand, with the ground surface by a smoke exhaust pipe, and on the other hand, with each isolated room by a separate line flue gas outlet, brought into the corresponding room at the ceiling level, while the compressed nitrogen storage unit, the control unit and the intermediate flue gas tank are located in a separate isolated room of a special fortification structure, and each distribution line for the supply of compressed nitrogen is brought into the corresponding isolated room on the lower level at the floor surface and is equipped at the end with a gas ejector, in which compressed nitrogen is used as an active gas, and flue gases are sucked into the gas ejector through a passive gas pipeline from the upper part along premises.

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