Liquid nitrogen fire extinguishing device

Abstract

The utility model belongs to the field of fire fighting equipment, and provides a liquid nitrogen fire extinguishing device which comprises a cabinet, a liquid nitrogen system, a driving system and a control system. Wherein the cabinet can move; the liquid nitrogen system comprises a liquid nitrogen bottle which is arranged in the cabinet and is used for storing liquid nitrogen, and further comprises a liquid nitrogen outlet pipe which is communicated with the liquid nitrogen bottle and is used for being connected with a target spraying pipeline; the driving system comprises a driving bottle arranged in the cabinet and used for storing driving gas, and further comprises a high-pressure hose used for communicating the liquid nitrogen bottle with the driving bottle; the control system comprises a controller installed on the cabinet and used for being connected with the alarm system, and further comprises a first electromagnetic valve connected to the liquid nitrogen outlet pipe and a second electromagnetic valve connected to the high-pressure hose, and the first electromagnetic valve and the second electromagnetic valve are both connected with the controller and can be controlled by the controller to be opened and closed.

Description

Technical Field

[0001] This application belongs to the field of fire protection equipment, and in particular relates to a liquid nitrogen fire extinguishing device. Background Technology

[0002] In containerized energy storage systems or large-scale energy storage power stations, liquid nitrogen fire extinguishing devices are typically required. Existing liquid nitrogen fire extinguishers are usually large in size and fixed to support structures, resulting in low integration. Due to the limited space in these energy storage systems, fixed liquid nitrogen fire extinguishing devices lack flexibility, making installation and maintenance inconvenient, and replenishment difficult after liquid nitrogen consumption. Therefore, it is necessary to solve these technical problems. Summary of the Invention

[0003] The purpose of this application is to provide a liquid nitrogen fire extinguishing device to solve the technical problem of poor flexibility in the use of existing liquid nitrogen fire extinguishing devices.

[0004] To achieve the above objectives, the technical solution adopted in this application is: to provide a liquid nitrogen fire extinguishing device, comprising:

[0005] The cabinet / box is movable;

[0006] The liquid nitrogen system includes a liquid nitrogen cylinder disposed inside the cabinet for storing liquid nitrogen, and a liquid nitrogen outlet pipe connected to the liquid nitrogen cylinder for connecting to a target spray pipe;

[0007] The drive system includes a drive cylinder disposed inside the cabinet for storing the drive gas, and a high-pressure hose for connecting the liquid nitrogen cylinder and the drive cylinder.

[0008] The control system includes a controller mounted on the cabinet for connection to an alarm system, and a first solenoid valve connected to the liquid nitrogen outlet pipe and a second solenoid valve connected to the high-pressure hose. Both the first solenoid valve and the second solenoid valve are connected to the controller and can be opened and closed by the controller.

[0009] Optionally, the liquid nitrogen system further includes a functional tube, a first branch tube, and a liquid filling tube. The functional tube is connected to the liquid nitrogen bottle and forms a detection interface for connecting to a target level gauge. The first branch tube is connected to the functional tube and is open at one end away from the functional tube. The liquid filling tube is connected to the liquid nitrogen outlet pipe and forms a replenishment interface at one end away from the liquid nitrogen outlet pipe. The end of the liquid filling tube that is connected to the liquid nitrogen outlet pipe is located between the first solenoid valve and the liquid nitrogen bottle.

[0010] The control system further includes a first manual valve and a second manual valve. The first manual valve is disposed on the first branch pipe and is used to control and adjust the opening and closing of the first branch pipe. The second manual valve is disposed on the liquid filling pipe and is used to adjust the opening and closing of the liquid filling pipe.

[0011] Optionally, the liquid nitrogen system further includes a second branch pipe connected to the functional tube, and the end of the high-pressure hose away from the drive bottle is connected to the second branch pipe and connected to the liquid nitrogen bottle in sequence through the second branch pipe and the functional tube;

[0012] The control system also includes a third manual valve, which is disposed on the second branch pipe and used to control the on / off state of the second branch pipe.

[0013] Optionally, the liquid nitrogen system further includes an expansion tube connected to the functional tube;

[0014] The first branch pipe and the second branch pipe are connected to the expansion pipe at intervals and communicate with the functional pipe through the expansion pipe.

[0015] Optionally, the liquid nitrogen system further includes a number of safety relief valves connected to the expansion tube and capable of opening when a predetermined pressure is exceeded;

[0016] The safety relief valve is located between the second branch pipe and the functional pipe.

[0017] Optionally, the liquid nitrogen system further includes a pressure gauge connected to the expansion tube and capable of detecting the pressure inside the expansion tube.

[0018] Optionally, the liquid nitrogen system further includes a pressure sensor connected to the expansion tube and capable of detecting the internal pressure of the expansion tube;

[0019] The pressure sensor is communicatively connected to the controller.

[0020] Optionally, the liquid nitrogen fire extinguishing device further includes a liquid nitrogen refrigeration system and a refrigeration circulation pipe;

[0021] The liquid nitrogen refrigeration system is communicatively connected to the controller and can be turned on or off in a controlled manner. The refrigeration circulation pipe connects the liquid nitrogen refrigeration system and the liquid nitrogen bottle, forming a circulation loop for transporting liquid nitrogen between the liquid nitrogen refrigeration system and the liquid nitrogen bottle.

[0022] Optionally, the liquid nitrogen fire extinguishing device further includes an insulation layer fitted over the outside of the refrigeration circulation pipe for heat preservation of the refrigeration circulation pipe.

[0023] Optionally, the cabinet is also provided with heat dissipation windows for heat dissipation of the liquid nitrogen refrigeration system.

[0024] The beneficial effects of the liquid nitrogen fire extinguishing device provided in this application are as follows: Compared with the prior art, the liquid nitrogen fire extinguishing device in this application has a movable cabinet design, which makes the entire device easy to transport and flexibly deployed to different fire locations, overcoming the shortcomings of the prior art where the device is inconvenient to fix. In addition, when the alarm system detects a fire signal and transmits it to the controller, the controller can simultaneously or in a logical sequence automatically open the second solenoid valve to allow the driving gas in the drive cylinder to enter the liquid nitrogen cylinder through the high-pressure hose for pressurization, and open the first solenoid valve to allow the pressurized liquid nitrogen to be sprayed out from the liquid nitrogen outlet pipe for fire extinguishing. This automatic control process does not require manual intervention to operate the valves, realizing a rapid automatic response from alarm to fire extinguishing without manual intervention, further improving the flexibility of use, which is far superior to the prior art. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the overall structure of the liquid nitrogen fire extinguishing device in the embodiments of this application;

[0027] Figure 2 This is a side view of the overall structure of the liquid nitrogen fire extinguishing device in the embodiments of this application;

[0028] Figure 3 This is a schematic diagram of the overall structure of the liquid nitrogen system in the embodiments of this application;

[0029] Figure 4 This is a schematic diagram of the overall structure of the drive system in the embodiments of this application.

[0030] The following are the reference numerals in the attached figures: 100, cabinet; 101, heat dissipation window; 200, liquid nitrogen cylinder; 201, liquid nitrogen outlet pipe; 202, functional pipe; 203, first branch pipe; 204, liquid filling pipe; 205, detection interface; 206, liquid replenishment interface; 207, second branch pipe; 208, expansion pipe; 209, safety relief valve; 210, pressure gauge; 211, pressure sensor; 300, drive bottle; 301, high-pressure hose; 400, controller; 401, first solenoid valve; 402, second solenoid valve; 403, first manual valve; 404, second manual valve; 405, third manual valve; 500, liquid nitrogen refrigeration system; 501, refrigeration circulation pipe; 502, insulation layer. Detailed Implementation

[0031] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0032] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0033] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0035] Please refer to the following: Figures 1 to 4 The present application provides a liquid nitrogen fire extinguishing device according to an embodiment. This liquid nitrogen fire extinguishing device includes a cabinet 100, a liquid nitrogen system, a drive system, and a control system. Wherein:

[0036] The cabinet 100 is movable. In this embodiment, the movable cabinet 100 can be achieved by installing wheels at the bottom of the cabinet 100. Preferably, casters or commonly used casters can be installed. The liquid nitrogen system includes a liquid nitrogen cylinder 200 disposed inside the cabinet 100 for storing liquid nitrogen, and a liquid nitrogen outlet pipe 201 connected to the liquid nitrogen cylinder 200 for connecting to the target spray pipe; the drive system includes a drive cylinder 300 disposed inside the cabinet 100 for storing drive gas, and a high-pressure hose 301 for connecting the liquid nitrogen cylinder 200 and the drive cylinder 300; in this embodiment, the drive gas stored in the drive cylinder 300 can be nitrogen or high-pressure air. The control system includes a controller 400 mounted on the cabinet 100 and used for connection to the alarm system, as well as a first solenoid valve 401 connected to the liquid nitrogen outlet pipe 201 and a second solenoid valve 402 connected to the high-pressure hose 301. Both the first solenoid valve 401 and the second solenoid valve 402 are connected to the controller 400 and can be controlled by the controller 400 to open and close. In this embodiment, the controller 400, the first solenoid valve 401, and the solenoid valves can all be selected from commonly used structures in the art. The alarm system includes smoke sensors, temperature sensors, infrared visual sensors, etc., arranged in the protected area. These sensors are electrically connected to the controller 400 and also to the fire alarm central control system. For example, in this embodiment, the controller 400 can be a Siemens PLC control system commonly used in the art, which will not be described in detail here.

[0037] According to the structure provided in this embodiment, the liquid nitrogen fire extinguishing device in this embodiment is movable due to the cabinet 100 design, which allows the entire device to be easily transported and flexibly deployed to different fire locations, overcoming the shortcomings of the inconvenience of fixing the device in the prior art. In addition, when the alarm system detects a fire signal and transmits it to the controller 400, the controller 400 can simultaneously or in logical sequence automatically open the second solenoid valve 402 to allow the driving gas in the drive bottle 300 to enter the liquid nitrogen bottle 200 through the high-pressure hose 301 for pressurization, and open the first solenoid valve 401 to allow the pressurized liquid nitrogen to be sprayed out from the liquid nitrogen outlet pipe 201 for fire extinguishing. This automatic control process does not require manual intervention to operate the valves, realizing a rapid automatic response from alarm to fire extinguishing without manual intervention, further improving the flexibility of use, which is far superior to the prior art.

[0038] In another embodiment of this application, please refer to [the relevant document / reference]. Figures 1 to 4The liquid nitrogen system also includes a functional tube 202, a first branch tube 203, and a liquid filling tube 204. The functional tube 202 is connected to the liquid nitrogen cylinder 200 and forms a detection interface 205 for connecting to the target liquid level gauge. The first branch tube 203 is connected to the functional tube 202 and has an open end away from the functional tube 202. The liquid filling tube 204 is connected to the liquid nitrogen outlet tube 201 and forms a replenishment interface 206 at the end away from the liquid nitrogen outlet tube 201. The end of the liquid filling tube 204 that is connected to the liquid nitrogen outlet tube 201 is located between the first solenoid valve 401 and the liquid nitrogen cylinder 200. The control system also includes a first manual valve 403 and a second manual valve 404. The first manual valve 403 is installed on the first branch tube 203 and is used to control and adjust the opening and closing of the first branch tube 203. The second manual valve 404 is installed on the liquid filling tube 204 and is used to adjust the opening and closing of the liquid filling tube 204.

[0039] In this embodiment, the detection interface 205 formed on the functional tube 202 allows operators or automated systems to monitor the liquid nitrogen level in the liquid nitrogen cylinder 200 in real time via a connected level gauge, providing a basis for subsequent replenishment operations or fire extinguishing performance evaluation. When the liquid nitrogen fire extinguishing device in this embodiment needs to be replenished with liquid nitrogen, the operator first connects the external liquid nitrogen delivery pipeline to the replenishment interface 206 of the filling pipe 204, and then opens the first manual valve 403 on the first branch pipe 203 to connect the open end of the first branch pipe 203 to the atmosphere. Then, the second manual valve 404 on the filling pipe 204 is opened to control the inflow rate of liquid nitrogen. At this time, external liquid nitrogen flows into the liquid nitrogen cylinder 200 through the filling pipe 204 under pressure, while the gas displaced in the liquid nitrogen cylinder 200 (mainly evaporated nitrogen) can be discharged into the atmosphere through the functional tube 202, the first branch pipe 203, and the opened first manual valve 403, avoiding the accumulation of gas pressure in the cylinder that would hinder the smooth replenishment of liquid nitrogen. After replenishment is complete, first close the second manual valve 404, then close the first manual valve 403, and finally disconnect the external liquid nitrogen supply line.

[0040] Based on the structure provided in this embodiment, the liquid nitrogen fire extinguishing device achieves rapid and safe on-site liquid replenishment. This means that after arriving at any deployment location, the mobile fire extinguishing device can replenish the medium through simple operations without relying on complex fixed refueling facilities or returning to a dedicated station, thus further improving the flexibility of use of the liquid nitrogen fire extinguishing device in this embodiment.

[0041] In another embodiment of this application, please refer to [the relevant document / reference]. Figures 1 to 4The liquid nitrogen system also includes a second branch pipe 207 connected to the functional pipe 202. The end of the high-pressure hose 301 away from the drive bottle 300 is connected to the second branch pipe 207 and is connected to the liquid nitrogen bottle 200 in sequence through the second branch pipe 207 and the functional pipe 202. The control system also includes a third manual valve 405, which is installed on the second branch pipe 207 and used to control the opening and closing of the second branch pipe 207.

[0042] According to the structure provided in this embodiment, the core function of the third manual valve 405 is to manually disconnect the connection between the high-pressure hose 301 and the liquid nitrogen cylinder 200. When the driving gas in the driving cylinder 300 is exhausted or the pressure is insufficient, the operator can first close this third manual valve 405 to isolate the liquid nitrogen cylinder 200 and subsequent pipelines from the driving system. Thus, the replacement or replenishment of the driving cylinder 300 can be carried out safely and quickly without affecting the sealing of the liquid nitrogen cylinder 200 and other parts of the system. This can further improve the flexibility of the liquid nitrogen fire extinguishing device in this embodiment.

[0043] In another embodiment of this application, please refer to [the relevant document / reference]. Figures 1 to 4 The liquid nitrogen system also includes an expansion pipe 208 connected to the functional pipe 202; the first branch pipe 203 and the second branch pipe 207 are spaced apart and connected to the expansion pipe 208 and connected to the functional pipe 202 through the expansion pipe 208. According to the structure provided in this embodiment, the expansion pipe 208, as an integrated connecting component, can make the piping layout of the liquid nitrogen fire extinguishing device in this embodiment more compact and orderly, which is convenient for installation and arrangement within the limited space of the cabinet 100. At the same time, it also reserves space and convenience for the subsequent addition of other functional interfaces (such as safety valves, pressure detection, etc.), which can further improve the flexibility of use of the liquid nitrogen fire extinguishing device in this embodiment.

[0044] In another embodiment of this application, please refer to [the relevant document / reference]. Figures 1 to 4 The liquid nitrogen system also includes several safety relief valves 209 connected to the expansion tube 208 and capable of opening when the pressure exceeds a predetermined value; the safety relief valves 209 are located between the second branch tube 207 and the functional tube 202.

[0045] According to the structure provided in this embodiment, the safety relief valve 209 provides a crucial safety guarantee for the liquid nitrogen fire extinguishing device, effectively protecting the liquid nitrogen cylinder 200 and subsequent pipelines. This safety design enables the liquid nitrogen fire extinguishing device to have automatic safety protection capabilities when flexibly deployed in various environments, thus further improving the flexibility of use of the liquid nitrogen fire extinguishing device in this embodiment.

[0046] In another embodiment of this application, please refer to [the relevant document / reference]. Figures 1 to 4The liquid nitrogen system also includes a pressure gauge 210 connected to the expansion tube 208 and capable of detecting the internal pressure of the expansion tube 208. According to the structure provided in this embodiment, the pressure gauge 210 can provide operators with intuitive pressure indications. Operators can quickly read the pressure status of key points of the system without relying on a complex electrical control system, which facilitates rapid on-site inspection, debugging, or fault diagnosis. This can further improve the flexibility of the liquid nitrogen fire extinguishing device in this embodiment.

[0047] In another embodiment of this application, please refer to [the relevant document / reference]. Figures 1 to 4 The liquid nitrogen system also includes a pressure sensor 211 connected to the expansion tube 208 and capable of detecting the internal pressure of the expansion tube 208; the pressure sensor 211 is communicatively connected to the controller 400. According to the structure provided in this embodiment, the pressure sensor 211 transmits the pressure signal within the expansion tube 208 to the controller 400 in real time. The controller 400 can then monitor the system pressure status, such as determining whether the driving gas has been successfully injected and whether the pipeline pressure is normal. This design incorporates pressure monitoring into the automatic control system, improving the intelligence and automation level of the mobile device, enabling it to operate more reliably and safely in flexible fire extinguishing scenarios that require unattended operation or remote activation. This also further enhances the flexibility of the liquid nitrogen fire extinguishing device in this embodiment.

[0048] In another embodiment of this application, please refer to [the relevant document / reference]. Figures 1 to 4 The liquid nitrogen fire extinguishing device also includes a liquid nitrogen cooling system 500 and a cooling circulation pipe 501. The liquid nitrogen cooling system 500 is communicatively connected to the controller 400 and can be controlled to open or close. The cooling circulation pipe 501 connects the liquid nitrogen cooling system 500 and the liquid nitrogen cylinder 200, forming a circulation loop for transporting liquid nitrogen between the liquid nitrogen cooling system 500 and the liquid nitrogen cylinder 200. In this embodiment, the liquid nitrogen cooling system 500 is communicatively connected to the controller 400 in ways including, but not limited to, electrical connections or wireless signal connections commonly used in the art.

[0049] Because liquid nitrogen inevitably absorbs heat from the environment during storage, its temperature rises and it vaporizes, causing the pressure inside the liquid nitrogen cylinder 200 to increase. The pressure sensor 211, connected to the expansion tube 208, monitors this pressure signal in real time and feeds it back to the controller 400. When the pressure value fed back by the pressure sensor 211 reaches the upper threshold, it indicates that the temperature inside the liquid nitrogen cylinder 200 is too high and evaporation is intensified. The controller 400 then automatically starts the liquid nitrogen refrigeration system 500. After the liquid nitrogen refrigeration system 500 starts working, it drives liquid nitrogen to flow out of the liquid nitrogen cylinder 200, enters the refrigeration system through the refrigeration circulation pipe 501 to be cooled, and then returns the cooled liquid nitrogen to the liquid nitrogen cylinder 200 through the circulation pipe. This cycle continues, achieving continuous cooling of the liquid nitrogen inside the cylinder. As the temperature of the liquid nitrogen inside the cylinder decreases, its saturated vapor pressure decreases accordingly, and the pressure value monitored by the pressure sensor 211 also falls back to the normal range. When the pressure value is lower than the lower threshold set by the controller 400, the controller 400 shuts down the liquid nitrogen refrigeration system 500, stops refrigeration, and enters a low-power standby state.

[0050] According to the structure provided in this embodiment, the liquid nitrogen refrigeration system 500 can effectively suppress the evaporation loss of liquid nitrogen caused by environmental heat intrusion, and maintain a low-pressure stable state in the liquid nitrogen cylinder 200 for a long time. This design greatly improves the standby endurance and environmental adaptability of the liquid nitrogen fire extinguishing device in this embodiment, enabling it to be flexibly deployed in various environments (especially high-temperature environments) and maintain a ready-to-use state without frequent liquid replenishment. This also further improves the flexibility of use of the liquid nitrogen fire extinguishing device in this embodiment.

[0051] In another embodiment of this application, please refer to [the relevant document / reference]. Figures 1 to 4 The liquid nitrogen fire extinguishing device also includes an insulation layer 502 that is fitted over the refrigeration circulation pipe 501 and used to keep the refrigeration circulation pipe 501 warm. According to the structure provided in this embodiment, the insulation layer 502 wrapped around the refrigeration circulation pipe 501 can effectively reduce the cooling loss of liquid nitrogen during circulation and improve the efficiency of the liquid nitrogen refrigeration system 500. This also further improves the flexibility of use of the liquid nitrogen fire extinguishing device in this embodiment. It is understood that the liquid nitrogen refrigeration system 500 can adopt existing technology.

[0052] In another embodiment of this application, please refer to [the relevant document / reference]. Figures 1 to 4 The cabinet 100 is also provided with a heat dissipation window 101 for heat dissipation of the liquid nitrogen refrigeration system 500. According to the structure provided in this embodiment, the heat dissipation window 101 can ensure that the liquid nitrogen refrigeration system 500 can effectively dissipate heat to the external environment in the sealed cabinet 100, preventing it from becoming less efficient or damaged due to overheating. This can also further improve the flexibility of use of the liquid nitrogen fire extinguishing device in this embodiment.

[0053] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A liquid nitrogen fire extinguishing apparatus, characterized by, include: The cabinet (100) is movable; The liquid nitrogen system includes a liquid nitrogen cylinder (200) disposed inside the cabinet (100) for storing liquid nitrogen, and a liquid nitrogen outlet pipe (201) connected to the liquid nitrogen cylinder (200) for connecting to a target spray pipe. The drive system includes a drive cylinder (300) disposed inside the cabinet (100) for storing the drive gas, and a high-pressure hose (301) for connecting the liquid nitrogen cylinder (200) and the drive cylinder (300). The control system includes a controller (400) mounted on the cabinet (100) for connection to an alarm system, and a first solenoid valve (401) connected to the liquid nitrogen outlet pipe (201) and a second solenoid valve (402) connected to the high-pressure hose (301). Both the first solenoid valve (401) and the second solenoid valve (402) are connected to the controller (400) and can be controlled to open and close by the controller (400).

2. The liquid nitrogen fire extinguishing device as described in claim 1, characterized in that: The liquid nitrogen system further includes a functional tube (202), a first branch tube (203), and a liquid filling tube (204). The functional tube (202) is connected to the liquid nitrogen bottle (200) and forms a detection interface (205) for connecting to a target level gauge. The first branch tube (203) is connected to the functional tube (202) and the end of the first branch tube (203) away from the functional tube (202) is open. The liquid filling tube (204) is connected to the liquid nitrogen outlet tube (201) and forms a replenishment interface (206) at the end away from the liquid nitrogen outlet tube (201). The end of the liquid filling tube (204) that is connected to the liquid nitrogen outlet tube (201) is located between the first solenoid valve (401) and the liquid nitrogen bottle (200). The control system further includes a first manual valve (403) and a second manual valve (404). The first manual valve (403) is disposed on the first branch pipe (203) and is used to control and adjust the opening and closing of the first branch pipe (203). The second manual valve (404) is disposed on the liquid filling pipe (204) and is used to adjust the opening and closing of the liquid filling pipe (204).

3. The liquid nitrogen fire extinguishing device as described in claim 2, characterized in that: The liquid nitrogen system also includes a second branch pipe (207) connected to the functional tube (202). The end of the high-pressure hose (301) away from the drive bottle (300) is connected to the second branch pipe (207) and is connected to the liquid nitrogen bottle (200) in sequence through the second branch pipe (207) and the functional tube (202). The control system also includes a third manual valve (405), which is disposed on the second branch pipe (207) and used to control the on / off state of the second branch pipe (207).

4. The liquid nitrogen fire extinguishing device as described in claim 3, characterized in that: The liquid nitrogen system also includes an expansion tube (208) connected to the functional tube (202). The first branch pipe (203) and the second branch pipe (207) are connected at intervals to the expansion pipe (208) and communicate with the functional pipe (202) through the expansion pipe (208).

5. The liquid nitrogen fire extinguishing device as described in claim 4, characterized in that: The liquid nitrogen system also includes a number of safety relief valves (209) connected to the expansion tube (208) and capable of opening when a predetermined pressure is exceeded. The safety relief valve (209) is located between the second branch pipe (207) and the functional pipe (202).

6. The liquid nitrogen fire extinguishing device as described in claim 4, characterized in that: The liquid nitrogen system also includes a pressure gauge (210) connected to the expansion tube (208) and capable of detecting the internal pressure of the expansion tube (208).

7. The liquid nitrogen fire extinguishing device as described in claim 4, characterized in that: The liquid nitrogen system also includes a pressure sensor (211) connected to the expansion tube (208) and capable of detecting the internal pressure of the expansion tube (208). The pressure sensor (211) is communicatively connected to the controller (400).

8. The liquid nitrogen fire extinguishing device as described in claim 7, characterized in that: The liquid nitrogen fire extinguishing device also includes a liquid nitrogen refrigeration system (500) and a refrigeration circulation pipe (501). The liquid nitrogen refrigeration system (500) is communicatively connected to the controller (400) and can be turned on or off in a controlled manner. The refrigeration circulation pipe (501) connects the liquid nitrogen refrigeration system (500) and the liquid nitrogen bottle (200) and forms a circulation loop for transporting liquid nitrogen between the liquid nitrogen refrigeration system (500) and the liquid nitrogen bottle (200).

9. The liquid nitrogen fire extinguishing device as described in claim 8, characterized in that: The liquid nitrogen fire extinguishing device also includes an insulation layer (502) that is fitted over the outside of the refrigeration circulation pipe (501) and is used to keep the refrigeration circulation pipe (501) warm.

10. The liquid nitrogen fire extinguishing device as described in claim 8 or 9, characterized in that: The cabinet (100) is also provided with a heat dissipation window (101) for dissipating heat from the liquid nitrogen refrigeration system (500).

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