Ground direct injection type liquid nitrogen fire preventing and extinguishing system

Abstract

The invention discloses a ground direct injection type liquid nitrogen fire preventing and extinguishing system. An outlet of a liquid nitrogen tank truck of the system is connected with an inlet of a reciprocating type low-temperature liquid pump, an outlet of the reciprocating type low-temperature liquid pump is connected with a liquid inlet of the upper portion of a buffering tank, a liquid outlet of the lower portion of the buffering tank is connected with a vacuum low-temperature heat insulation tube, the vacuum low-temperature heat insulation tube is connected with a nitrogen injection tube and a nitrogen gas delivery tube, a gas exhaust opening at the upper end of the buffering tank is connected with the nitrogen gas delivery tube, the upper portion of the buffering tank is a single-layered shell, and the upper end of the buffering tank is connected with a decompression valve. Key technical problems that gas phase and liquid phase are separated after liquid nitrogen is vaporized and the nitrogen injection tube is blocked are avoided. The ground direct injection type liquid nitrogen fire preventing and extinguishing system is simple in structure and convenient in installation, is safe and reliable, and effectively avoids problems of gas blockage, intermittent spring and the like in a liquid nitrogen injection process, and liquid nitrogen filling efficiency is improved by 20% at least as compared with traditional direct liquid nitrogen filling process. The ground direct injection type liquid nitrogen fire preventing and extinguishing system is particularly applicable to preventing and extinguishing fire of hidden fire sources of shallow-buried deep coal mine underground worked out sections.

Description

technical field [0001] The invention relates to a coal mine liquid nitrogen fire prevention device. Background technique [0002] At present, about 50% of the coal mines in our country have the danger of spontaneous combustion, and the spontaneous combustion of coal seriously threatens the safe production of mines and the lives of workers. It is difficult to implement conventional fire prevention and extinguishing techniques such as yellow mud grouting, inhibitors, gels, foams, etc., in some mining areas in semi-arid areas, due to conditions such as lack of water and soil, and can only be implemented locally . In addition, because it is difficult to judge the location of the fire source, pouring mud or colloid, the coverage is small, the diffusion range is limited, it is difficult to reach the fire source, and it is easy to cause mine environmental pollution. The normal nitrogen fire prevention and extinguishing technology has poor cooling effect, and other auxiliary fire ...

AI Technical Summary

Problems solved by technology

It is difficult to implement conventional fire prevention and extinguishing techniques such as yellow mud grouting, inhibitors, gels, foams, etc., in some mining areas in semi-arid areas, due to conditions such as lack of water and soil, and can only be implemented locally

In addition, because the location of the fire source is difficult to judge, the coverage of mud or colloid is small, the diffusion range is limited, it is difficult to reach the fire source, and it is easy to cause mine environmental pollution

Normal nitrogen fire prevention and extinguishing technology, the cooling effect is poor, often need to cooperate with other auxiliary fire extinguishing measures during the fire extinguishing period, the fire extinguishing cycle is long

The vaporization of liquid nitrogen can absorb a large amount of heat and reduce the temperature of the fire zone. However, the liquid nitrogen fire prevention technology has exposed shortcomings in field practice: liquid nitrogen is very easy to vaporize under normal temperature conditions, and the volume between liquid nitrogen and nitrogen When the vaporization ratio is above 1:600, the vaporized nitrogen in the borehole hinders the further flow of liquid nitrogen, and is prone to gas blockage, geysers, etc., making it difficult for liquid nitrogen to enter the fire prevention area, affecting the efficiency of liquid nitrogen injection and Anti-fire extinguishing effect

This is also the main reason restricting the large-scale application of liquid nitrogen fire prevention and extinguishing technology.

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