RU2311937C2 - Nitrogen cryogenic plant for fire extinguishment in closed objects - Google Patents

Abstract

FIELD: fire-fighting, particularly devices using inert gas for fire-extinguishment in space to be protected.

SUBSTANCE: plant comprises cryogenic vessel with liquid nitrogen, gas discharge means, fire-extinguishant supply pipeline, controllable valve, at least one detector and evaporator arranged outside the cryogenic vessel. The evaporator is communicated with lower vessel part filled with liquid nitrogen by means of lower evaporator end and with cryogenic vessel head space by upper end thereof. Controllable valve is installed in initial evaporator section. Fire-extinguishant supply pipeline is made as cryogenic pipeline provided with controllable valve. One cryogenic pipeline end is communicated with cryogenic vessel area filled with liquid nitrogen. Another end thereof has fire detector linked to controllable valves of pipeline and evaporator. Fire detector is made as temperature sensor or smoke sensor or gas sensor. Temperature sensor may be made as bimetal ring formed as annular constant magnet covered with ferromagnetic shell of material with Curie point close to liquid nitrogen boiling temperature. Bimetal ring is thermally isolated from coupling body. Magnetically operated contact, namely reed switch, is built in coupling body. Controllable valve is made as heat-sensitive valve and comprises body, inlet and outlet popes, slide and seat. Outlet pipe is diffuser. The slide is connected to working heat-sensitive spring made of shape-memory material and secured to valve body. The plant may have control panel. The cryogenic vessel may be conveyed, for instance by means of wheel pair.

EFFECT: increased efficiency by optimal inert gas stock usage due to fire-extinguishant phase composition control by regulation of supplied cryogenic liquid flow rate via cryogenic pipeline.

6 cl, 2 dwg

Description

The invention relates to fire fighting equipment, in particular to installations for extinguishing fires with inert gases in a protected volume. Using the proposed installation it is possible to extinguish class A fires (burning solid materials) and Class B (burning liquid products) in closed heated rooms, such as libraries, archives, museums, offices, hardware rooms, water transport premises, railway cars, warehouses, textile rooms , shoe and other industries.

Inert gases have the property of quickly mixing with combustible vapors and gases, while lowering the oxygen concentration, helping to stop the burning of most combustible substances. The extinguishing effect of inert gases is also due to the fact that they dilute the combustible medium, while lowering the temperature in the fire, resulting in a difficulty in the combustion process.

A known method of volumetric fire extinguishing (p. RF No. 2200044, A62C 5/00, publ. 10.03.2003), in which a fire extinguishing concentration of nitrogen is created in the combustion zone by its continuous generation, oxygen is removed from the volume of the protected space, while nitrogen generation and removal oxygen is carried out by gas separation plants with nitrogen intake from the volume of the protected space, from the volumes of neighboring rooms, outside or in the combination of the fence, and to enhance the fire extinguishing effect, the nitrogen is cooled or liquefied and fed into the combustion zone in a sprayed form unserved areas and pressurized gas mixture with low oxygen content of up to 5 vol.% or less, without causing burning.

Closest to the technical nature of the present invention is an automatic nitrogen fire extinguishing installation (p. RF No. 2041724, А62С 35/00, publ. 08/20/1995), containing compressed nitrogen cylinders, a gearbox, electrically operated valves, a filling pipe, gas discharge, a boost evaporator , isothermal tank, hollow pipes connected through controlled valves and pipelines to a gasifier, which is connected to a distribution network and exhaust nozzles. Fire detectors are connected to the control unit. A pressure sensor is installed on the pressure pipe and is connected to the control unit.

The disadvantages of these technical solutions are:

- the impossibility of regulating the supply of extinguishing agent depending on the intensity of the ignition of the object, as a result of which irreplaceable loss of objects surrounding the object is possible;

- uneconomical use of inert gas reserves.

The objective of the invention is the optimal use of inert gas reserves by regulating the phase composition of the extinguishing agent, which is achieved by controlling the intensity of the supply of cryogenic liquid through the cryogenic pipeline.

The problem is solved in that in a cryogenic nitrogen installation to extinguish a fire in closed facilities, containing a cryogenic tank with liquid nitrogen, a gas vent, an extinguishing agent supply pipe, an adjustable valve, at least one detection sensor, an evaporator that is located outside the cryogenic tank and the lower end is in communication with its lower part filled with liquid nitrogen, and the upper end with the volume of its super-liquid space, moreover, an adjustable valve and a supply pipe are installed in the initial section of the evaporator extinguishing agent is made in the form of a cryogenic pipeline, an adjustable valve is installed on it, one end of the cryogenic pipeline is connected with a cryogenic tank in the zone filled with liquid nitrogen, a fire detection sensor is connected at its other end, connected with adjustable valves of the pipeline and the evaporator. The fire detection sensor may be a temperature sensor, or a smoke sensor, or a gas pollution sensor. The temperature sensor can be made in the form of a bimetallic ring made in the form of an annular permanent magnet coated with a sheath of ferromagnetic material with a Curie point close to the boiling point of liquid nitrogen, while the bimetallic ring is thermally insulated from the coupling body, opposite the bimetallic ring, is mounted in the coupling housing magnetically controlled contact - reed switch. The heat-sensitive valve may contain a housing, inlet and outlet nozzles, the valve itself, a seat, and the outlet nozzle is made in the form of a diffuser, and the valve itself is connected to a working heat-sensitive spring made of material with shape memory (metal with shape memory or a bimetal plate) and fixed in the valve body. The installation can be equipped with a control panel. The cryogenic tank may be movable, for example, by means of a pair of wheels.

Comparative analysis with the prototype allows us to conclude that the claimed technical solution meets the criterion of "novelty."

The proposed design of a cryogenic nitrogen installation for extinguishing a fire in closed objects has two stages of extinguishing agent supply, differing in the intensity of its supply, which leads to the optimal use of inert gas reserves and the maximum conservation of the extinguishing object and surrounding objects, which are often of particular value (historical, material , scientific, etc.).

The use of a cryogenic pipeline with an adjustable valve associated with a fire detection sensor can significantly reduce the time and improve the quality of the regeneration process, since the pumped volume is significantly reduced in the design and the hydraulic resistance is significantly reduced, which in turn significantly reduces the power consumption of the pumping means and reduces the energy costs of the pumping means.

Figure 1 shows the design of a cryogenic installation for extinguishing a fire in closed objects. Figure 2 shows a heat-sensitive valve.

The cryogenic nitrogen installation for extinguishing a fire in closed objects contains a cryogenic tank 1 with nitrogen, a gas discharge 2, a fire detection sensor 3, an evaporator 4, which is located outside the cryogenic tank 1 and its lower end is in communication with its lower part filled with liquid nitrogen P ₂ , and the upper - with the volume of its super-fluid space P ₁ , and at the initial section of the evaporator 4 an adjustable valve 5 is installed, a cryogenic pipeline 6 for supplying a fire extinguishing agent, an adjustable valve 7 is installed on it. One end of the cryogenic pipeline 6 connected with a cryogenic tank 1 in a zone filled with liquid nitrogen P ₂ , at its other end a fire detection sensor 3 is installed, connected with adjustable valves 5, 7 of the evaporator and the pipeline, respectively. The pipe 6 is equipped with couplings 8 and a bell 9. The fire detection sensor 3 may be a temperature sensor, or a smoke sensor (for example, an optical sensor), or a gas pollution sensor (for example, a concentration sensor). The temperature sensor is made in the form of a bimetallic ring, made in the form of an annular permanent magnet, coated with a sheath of ferromagnetic material with a Curie point close to the boiling point of liquid nitrogen, while the bimetallic ring is thermally insulated from the coupling body, opposite the bimetallic ring, a magnetically controlled contact is mounted in the coupling housing - reed switch. The heat-sensitive valve (Fig. 2) contains a housing 13, an inlet 12 and an outlet 17 nozzles, the valve 16 itself, a seat 15, the outlet nozzle 17 is made in the form of a diffuser, and the valve 16 itself is connected to a working heat-sensitive spring 14 made of material with shape memory and fixed in the valve body. The installation can be equipped with a control panel 10. The cryogenic tank 1 can be equipped with a pair of wheels 11.

The installation operates in two modes, depending on the intensity of the supply of extinguishing fluid: a) minimum flow (economical) and b) maximum flow. In the first case, liquid nitrogen is supplied through a cryogenic pipeline 6 to an enclosed space until the emission of combustion products ceases, and the liquid nitrogen supply intensity is controlled by a valve 7 connected to the fire detection sensor 3 so that liquid nitrogen is supplied at the outlet from the pipeline 6. In the protected object, nitrogen vapors having a low temperature contribute to lowering the temperature of the gaseous medium and surfaces in the storage object and reduce the oxygen content in the gaseous medium by displacing air from it while mixing it with the remaining part. If the temperature required in this object is not reached, a fire detection sensor 3 sends a signal to open valve 5 of evaporator 4, through which liquid nitrogen flows from cryogenic tank 1 to evaporator 4, where due to the large influx of heat from the environment, liquid nitrogen quickly evaporates, creating a large excess pressure in the volume of the superfluid space P ₁ necessary for the discharge of liquid nitrogen into the cryogenic pipeline 1, and a large isolation zone of oxygen access to the fire source is formed, which Improves fire fighting efficiency. The level of required pressure (in case of abnormal overpressure) in the super-fluid space is regulated by gas discharge 2.

The proposed fire extinguishing installation allows us to solve the problem of extinguishing a fire at industrial complexes located in closed facilities during spontaneous combustion or when processes of a different nature are carried out in them or in close proximity to them, for example, chemical (cable channels at launching stations of launch vehicles), physico-chemical physical (for example, when conducting explosive experiments in explosion-proof chambers), as well as during spontaneous combustion of cable channels in towers (television, navigation, etc. .d.), in tunnels, ship compartments, etc.

Claims (6)

1. A cryogenic nitrogen installation for extinguishing a fire in closed facilities, containing a cryogenic tank with liquid nitrogen, a gas vent, an extinguishing agent supply pipe, an adjustable valve, at least one fire detection sensor, an evaporator that is located outside the cryogenic tank and has a lower end in communication with its lower part, filled with liquid nitrogen, and the upper one, with the volume of its super-liquid space, moreover, an adjustable valve is installed in the initial section of the evaporator, characterized in that the fire extinguisher supply pipe The substance is made in the form of a cryogenic pipeline, an adjustable valve is installed on it, one end of the cryogenic pipeline is connected with a cryogenic tank in the zone filled with liquid nitrogen, and a fire detection sensor is connected at its other end, connected with the adjustable valves of the pipeline and the evaporator. 2. Installation according to claim 1, characterized in that the fire detection sensor is a temperature sensor, or a smoke sensor, or a gas pollution sensor. 3. Installation according to claim 2, characterized in that the temperature sensor is made in the form of a bimetallic ring made in the form of an annular permanent magnet coated with a sheath of ferromagnetic material with a Curie point close to the boiling point of liquid nitrogen, while the bimetallic ring is thermally insulated from the housing couplings opposite a bimetallic ring, a magnetically controlled contact - a reed switch is mounted in the clutch housing. 4. The installation according to claim 1, characterized in that the adjustable valve, made in the form of a heat-sensitive valve, contains a body, inlet and outlet pipes, the valve itself, a seat, the outlet pipe is made in the form of a diffuser, and the valve itself is connected to a working heat-sensitive spring, made of material with shape memory and fixed in the valve body. 5. Installation according to claim 1, characterized in that it is equipped with a control panel. 6. Installation according to claim 1, characterized in that the cryogenic tank has the ability to move, for example, by means of a pair of wheels.

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