Mobile liquid nitrogen fire extinguishing system and method for utility tunnel

Patent metadata

Field	Value
Publication number	US-12324939-B2
Application number	US-202018003312-A
Country	US
Kind code	B2
Filing date	Dec 2, 2020
Priority date	Jul 16, 2020
Publication date	Jun 10, 2025
Grant date	Jun 10, 2025

Abstract

A mobile liquid nitrogen fire extinguishing system for a utility tunnel is provided, including a liquid nitrogen production assembly, a fire extinguishing assembly, a monitoring device, and a liquid nitrogen conveying tubing. The mobile fire extinguishing assembly includes a liquid nitrogen storage tank and a liquid nitrogen booster pump. The liquid nitrogen storage tank is connected to the liquid nitrogen booster pump. The liquid nitrogen booster pump conveys liquid nitrogen to branch pipes in the utility tunnel through the liquid nitrogen conveying tubing. Liquid nitrogen injection ports are formed in each of the branch pipes. The liquid nitrogen production assembly is mobile and conveys the prepared liquid nitrogen to the liquid nitrogen storage tank. The monitoring device includes a first monitoring assembly and a second monitoring assembly.

First claim

What is claimed is:

1. A mobile liquid nitrogen fire extinguishing system for a utility tunnel, comprising:
a liquid nitrogen production assembly, a fire extinguishing assembly, a monitoring device, a liquid nitrogen conveying tubing, and a controller, wherein
the fire extinguishing assembly is arranged on a mobile platform, and comprises a liquid nitrogen storage tank and a liquid nitrogen booster pump; and a first liquid outlet on the liquid nitrogen storage tank is connected to the liquid nitrogen booster pump, the liquid nitrogen booster pump is provided with a second liquid outlet connected to a reserved interface of the liquid nitrogen conveying tubing, and conveys liquid nitrogen to branch pipes in the utility tunnel through the reserved interface of the liquid nitrogen conveying tubing, and liquid nitrogen injection ports are formed in each of the branch pipes;
the liquid nitrogen production assembly is mobile, and conveys the liquid nitrogen, which is prepared, into the liquid nitrogen storage tank;
the monitoring device comprises a proportional control valve, a first monitoring assembly that comprises a pressure gauge, a pressure regulating valve, a gas outlet device, and a pressure relief valve, and a second monitoring assembly that comprises a flow meter and a safety valve;
and the proportional control valve is located between the liquid nitrogen storage tank and the liquid nitrogen booster pump, the first monitoring assembly is mounted on the liquid nitrogen storage tank, and the second monitoring assembly is located between the liquid nitrogen booster pump and the liquid nitrogen conveying tubing; and
the controller is connected to the first monitoring assembly for pressure display and pressure regulation inside the liquid nitrogen storage tank, the controller is connected to the second monitoring assembly to control a flow of the liquid nitrogen input into the liquid nitrogen conveying tubing, the controller is connected to the proportional control valve to control a flow input into the liquid nitrogen booster pump, the controller is connected to the liquid nitrogen booster pump to control an output pressure, and the controller is connected to the liquid nitrogen production assembly to control opening and closing of the liquid nitrogen production assembly and liquid nitrogen conversion efficiency.

2. The mobile liquid nitrogen fire extinguishing system for a utility tunnel according to claim 1 , wherein the flow meter and the safety valve of the second monitoring assembly are connected in sequence.

3. The mobile liquid nitrogen fire extinguishing system for a utility tunnel according to claim 1 , wherein the liquid nitrogen production assembly comprises an air compressor, a nitrogen production machine, and a refrigeration liquefier which are all arranged in a mobile vehicle; and
the air compressor is provided with an air inlet on a side thereof, and an output end of the air compressor is connected to the nitrogen production machine and the refrigeration liquefier in sequence, and an output end of the refrigeration liquefier is connected to the liquid nitrogen storage tank.

4. The mobile liquid nitrogen fire extinguishing system for a utility tunnel according to claim 3 , wherein the branch pipes comprise three branch pipes arranged in layers and arranged at a top, a middle, and a bottom inside the utility tunnel respectively, each of the liquid nitrogen injection ports on a corresponding one of the three branch pipes is provided with a sensor, the sensor is connected to a master control of the utility tunnel, and the master control of the utility tunnel transmits alarm and positioning information to the controller.

5. The mobile liquid nitrogen fire extinguishing system for a utility tunnel according to claim 2 , wherein the liquid nitrogen production assembly and the liquid nitrogen storage tank are connected through a first metal hose, the liquid nitrogen storage tank and the liquid nitrogen booster pump are connected through a second metal hose, and the safety valve and the liquid nitrogen conveying tubing are connected through a third metal hose.

6. The mobile liquid nitrogen fire extinguishing system for a utility tunnel according to claim 4 , wherein the liquid nitrogen booster pump is provided with a gas outlet.

7. A mobile liquid nitrogen fire extinguishing method for a utility tunnel, comprising:
(a) when a fire occurs in a cabin of the utility tunnel, sensing a fire position by sensors at liquid nitrogen injection ports, feeding back a signal to a master control of the utility tunnel, controlling to close corresponding facilities in the utility tunnel by the master control of the utility tunnel, and sending alarm and positioning information to a controller, controlling a liquid nitrogen production assembly and a fire extinguishing assembly by the controller to move to a target location, and connecting the liquid nitrogen production assembly to the fire extinguishing assembly via a metal hose, and connecting the fire extinguishing assembly to a reserved interface of a liquid nitrogen conveying tubing through another metal hose; and
starting a liquid nitrogen booster pump by the controller; regulating an input flow of liquid nitrogen in a liquid nitrogen storage tank by a proportional control valve; after regulating an output pressure by the liquid nitrogen booster pump, enabling the liquid nitrogen enters the liquid nitrogen conveying tubing and branch pipes through a flow meter and a safety valve in sequence; and injecting the liquid nitrogen from the liquid nitrogen injection ports on each of the branch pipes into the utility tunnel to perform a liquid nitrogen fire extinguishing inside the utility tunnel;
(b) monitoring a pressure in the liquid nitrogen storage tank by a pressure gauge on the liquid nitrogen storage tank in real time, dividing the pressure into a filling range, a working range, and a dangerous range based on a magnitude of the pressure; if the pressure in the liquid nitrogen storage tank is in the filling range, starting the liquid nitrogen production assembly by the controller, such that surrounding air is extracted by an air compressor from an air inlet on a top of the air compressor for filtering and compression, and conveying the surrounding air to a nitrogen production machine for treatment, producing liquid nitrogen by a refrigeration liquefier by using nitrogen generated by the nitrogen production machine, and supplying the liquid nitrogen to the liquid nitrogen storage tank through a first metal hose; performing the liquid nitrogen fire extinguishing in the utility tunnel normally if the pressure is in the working range; and if the pressure is in the dangerous range, opening a pressure relief valve automatically, so as to discharge nitrogen gas generated after gasification of liquid nitrogen under heating, such that the pressure is recovered to the working range; and
(c) controlling an automatic simultaneous operation of a liquid nitrogen preparation, a liquid nitrogen storage, and the liquid nitrogen fire extinguishing by the controller; after the liquid nitrogen fire extinguishing is completed, controlling the liquid nitrogen production assembly by the controller such that the liquid nitrogen production assembly stops working when the pressure in the liquid nitrogen storage tank reaches the working range after the liquid nitrogen is supplemented.

8. The mobile liquid nitrogen fire extinguishing method for an utility tunnel according to claim 7 , wherein, in step, calculating an amount of the liquid nitrogen injected from each of the liquid nitrogen injection ports by:

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Assignees

• Univ China Mining

Inventors

• Zhang Guowei
• Guo Dong
• Li Huaxiang
• Sun Yinan
• Li Zheng
• Zhang Zhiwei
• Yan Su
• Huang Junbin

Classifications

• A62C35/023

  the extinguishing material being expelled by compressed gas, taken from storage tanks, or by generating a pressure gas (for foam generation A62C5/02) · CPC title

• A62C31/05

  with two or more outlets · CPC title

• A62C27/00

  Fire-fighting land vehicles · CPC title

• A62C99/0018

  using gases or vapours that do not support combustion, e.g. steam, carbon dioxide · CPC title

• A62C31/00

  Delivery of fire-extinguishing material (pumps F04; {suction or pressure} hoses, {joints or couplings therefor} F16L) · CPC title