A liquid nitrogen and liquid carbon dioxide mixing device

Abstract

The invention discloses a liquid nitrogen and liquid carbon dioxide mixing device, which comprises a tank body, a liquid carbon dioxide injection component, a nitrogen injection component, a liquid nitrogen injection pipe and a monitoring component. The output ends of the liquid carbon dioxide injection component and the nitrogen injection component are both plugged into the top of the tank body. The liquid carbon dioxide injection component is used to uniformly inject liquid carbon dioxide droplets into the tank body. The liquid nitrogen injection pipe is plugged and assembled on the lower side of the outer surface of the tank body. The monitoring component is assembled on the outer surface of the tank body. The lower end of the tank body is equipped with a regulating valve, and the lower end of the regulating valve is equipped with an output pipe. A temperature difference of high at the top and low at the bottom is achieved in the tank body and a certain pressure is maintained. Liquid carbon dioxide is injected by a lattice-type capillary tube, so that the carbon dioxide in the tank body is injected from the top in a rainy manner and is frozen into granular, powdered or snowflake-shaped dry ice at the bottom of the tank body, and freezing and clogging of the liquid carbon dioxide at the tank body inlet is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of coal production, and in particular provides a device for mixing liquid nitrogen and liquid carbon dioxide. Background Art

[0002] Gas fire extinguishing is one of the main means of fire prevention and extinguishing. Low-temperature gas not only has a suffocating effect, but also produces a good cooling and fire extinguishing effect.

[0003] Existing gas fire prevention and extinguishing mainly uses low-temperature carbon dioxide, nitrogen and other gases, which are injected into the high-temperature area of the goaf. Within the gas diffusion range, it can isolate oxygen and reduce the temperature of the fire area, thereby achieving the purpose of fire extinguishing.

[0004] Due to the limitations of the conditions at the fire extinguishing site, the conditions for preparing low-temperature gas are generally not available on site. Liquid carbon dioxide or liquid nitrogen can only be purchased from power plants, coal chemical companies and other enterprises, and then transported to the fire extinguishing site by tank trucks or tank trucks. After being vaporized into low-temperature gas, it is injected into the goaf.

[0005] Problems with existing technologies:

[0006] (1) After the liquid gas vaporizes, its cooling capacity for the fire zone decreases significantly, and its fire extinguishing capacity is weakened. Since the liquid gas is directly injected into the goaf, the pressure at the release port of the liquid gas will drop sharply, causing it to expand rapidly from liquid to gas. Due to the work done by the expansion, the temperature at the release port drops sharply, which can easily freeze the liquid carbon dioxide at the release port into dry ice, or freeze the liquid nitrogen, causing the release port to be blocked. Therefore, the process method of vaporization first and then injection is generally adopted, and the latent heat of vaporization cannot be used to extinguish the fire.

[0007] (2) A large amount of electricity is wasted. The preparation of liquid carbon dioxide and nitrogen requires cryogenic technology, which requires a large amount of electricity. Converting the liquid into gas requires electric heating for vaporization, which also consumes a lot of electricity. Summary of the Invention

[0008] To solve the above problems, the present invention provides a liquid nitrogen and liquid carbon dioxide mixing device, which vaporizes liquid nitrogen into nitrogen gas and uses the heat absorbed during the vaporization of liquid nitrogen to convert liquid carbon dioxide into granular or snowflake-shaped dry ice. The vaporized nitrogen gas is then used to transport the dry ice to high-temperature points in the goaf. The dry ice is heated and vaporized in the goaf, fully utilizing the latent heat of phase change to extinguish fires at high-temperature points while also reducing power consumption.

[0009] To achieve the above-mentioned object, the technical solution adopted by the present invention is: a liquid nitrogen and liquid carbon dioxide mixing device, comprising a tank body, a liquid carbon dioxide injection assembly, a nitrogen injection assembly, a liquid nitrogen injection pipe and a monitoring assembly, wherein the output ends of the liquid carbon dioxide injection assembly and the nitrogen injection assembly are both plugged into the top of the tank body, the liquid carbon dioxide injection assembly is used to uniformly inject liquid carbon dioxide droplets into the tank body, the liquid nitrogen injection pipe is plugged and assembled on the lower side of the outer surface of the tank body, the monitoring assembly is assembled on the outer surface of the tank body, and the monitoring assembly is used to monitor the temperature and pressure in the tank body, the lower end of the tank body is equipped with a regulating valve, and the lower end of the regulating valve is equipped with an output pipe.

[0010] Furthermore, the top of the tank body is an arc cover structure, the middle part is a barrel-shaped structure, and the bottom is a V-shaped structure. The outer surface of the tank body is provided with a heat-insulating layer.

[0011] Furthermore, the liquid carbon dioxide injection assembly includes a liquid carbon dioxide delivery main pipeline, a liquid carbon dioxide delivery branch pipeline and a liquid carbon dioxide injection pipe. Multiple liquid carbon dioxide delivery branch pipelines are symmetrically assembled on the front and rear sides of the liquid carbon dioxide delivery main pipeline. The liquid carbon dioxide injection pipes are evenly assembled on the lower side of the outer surface of the liquid carbon dioxide delivery main pipeline and the liquid carbon dioxide delivery branch pipeline, and the liquid carbon dioxide injection pipes pass through the top of the tank body.

[0012] Furthermore, the diameter of the injection end of the liquid carbon dioxide delivery main pipeline is larger than the diameter of the tail end.

[0013] Furthermore, the liquid carbon dioxide injection tubes are thin tubes, and the liquid carbon dioxide injection tubes are evenly distributed in a square lattice.

[0014] Furthermore, the nitrogen injection assembly includes a nitrogen delivery pipeline and a nitrogen injection pipe. Multiple nitrogen injection pipes are evenly arranged on the lower side of the outer surface of the nitrogen delivery pipeline, and the nitrogen injection pipes pass through the top of the tank body. The nitrogen injection pipes and the liquid carbon dioxide injection pipes are staggered.

[0015] Furthermore, the monitoring component includes a first temperature sensor, a pressure sensor and a second temperature sensor. The first temperature sensor and the pressure sensor are both arranged on the upper side of the outer surface of the tank body, and the second temperature sensor is arranged on the lower side of the outer surface of the tank body. The first temperature sensor is used to monitor the temperature of the upper area inside the tank body, the pressure sensor is used to monitor the pressure inside the tank body, and the second temperature sensor is used to monitor the temperature of the lower area inside the tank body.

[0016] Furthermore, an exhaust valve and a safety valve are provided on the top of the tank body.

[0017] The beneficial effects of using the present invention are:

[0018] 1. A temperature difference of high at the top and low at the bottom is achieved inside the tank, and a certain pressure is maintained. Liquid carbon dioxide is injected into the tank using a dot matrix capillary tube, so that the carbon dioxide in the tank is injected from the top in a rainy manner and freezes into granular, powdery or snowflake-shaped dry ice at the bottom of the tank, avoiding freezing and clogging of the liquid carbon dioxide at the tank entrance.

[0019] 2. The temperature of the liquid nitrogen injection point at the lower part of the tank body is low, which effectively prevents the liquid nitrogen from freezing and clogging at the tank entrance, and uses the low temperature of liquid nitrogen to quickly freeze the liquid carbon dioxide.

[0020] 3. Strong cooling capacity for goaf. The phase change heat absorption in liquid nitrogen and liquid carbon dioxide is fully retained. A mixture of nitrogen and dry ice is injected into the goaf. Dry ice absorbs a large amount of heat when vaporized in the goaf, thus avoiding the loss of cooling energy when it is injected into the goaf after vaporization.

[0021] 4. Gas suffocates fires more effectively in goafs. When the nitrogen and dry ice mixture enters the goaf, carbon dioxide, with its high density, diffuses toward the lower part of the goaf, while nitrogen, with its lower density, diffuses toward the upper part of the goaf. This creates a three-dimensional diffusion pattern within the goaf, overcoming the problem of limited diffusion direction for a single gas.

[0022] 5. Saves a lot of heating and vaporization electricity. In the goaf, dry ice vaporizes due to heat, making full use of the latent heat of phase change to extinguish the high-temperature points. Compared with the traditional method of vaporizing liquid carbon dioxide and liquid nitrogen through electric heating, it greatly reduces the consumption of electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a front cross-sectional view of the mixing device of the present invention.

[0024] Figure 2 This is a bottom view of the liquid carbon dioxide injection assembly of the present invention.

[0025] The accompanying drawings include: 1. tank body, 2. liquid carbon dioxide injection assembly, 201. liquid carbon dioxide delivery main pipeline, 202. liquid carbon dioxide delivery branch pipeline, 203. liquid carbon dioxide injection pipe, 3. nitrogen injection assembly, 301. nitrogen delivery pipeline, 302. nitrogen injection pipe, 4. liquid nitrogen injection pipe, 5. regulating valve, 6. output pipe, 7. insulation layer, 8. exhaust valve, 9. safety valve, 10. first temperature sensor, 11. pressure sensor, 12. second temperature sensor. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Reference Figure 1 and Figure 2 A liquid nitrogen and liquid carbon dioxide mixing device includes a tank body 1, a liquid carbon dioxide injection component 2, a nitrogen injection component 3, a liquid nitrogen injection pipe 4 and a monitoring component. The output ends of the liquid carbon dioxide injection component 2 and the nitrogen injection component 3 are both plugged into the top of the tank body 1. The liquid carbon dioxide injection component 2 is used to uniformly inject liquid carbon dioxide droplets into the tank body 1. The liquid nitrogen injection pipe 4 is plugged and assembled on the lower side of the outer surface of the tank body 1. The monitoring component is assembled on the outer surface of the tank body 1, and the monitoring component is used to monitor the temperature and pressure in the tank body. The lower end of the tank body 1 is equipped with a regulating valve 5, and the lower end of the regulating valve 5 is equipped with an output pipe 6.

[0028] Liquid carbon dioxide and liquid nitrogen undergo heat exchange and phase change in the tank body 1, and are eventually output and collected from the output pipe 6 in the form of a nitrogen and dry ice mixture. The nitrogen and dry ice mixture is used to cool and extinguish fires at high-temperature points in the goaf.

[0029] The temperature and pressure information obtained by the monitoring component is used to control the injection amount of the nitrogen injection component 3 and the liquid nitrogen injection pipe 4 and the opening of the regulating valve 5 to ensure that the nitrogen and dry ice mixture is collected.

[0030] The output pipe 6 is used to transport the nitrogen and dry ice mixture out of the tank body 1, and the regulating valve 5 is used to control the pressure in the tank body 1 within a certain range. If the pressure in the tank body 1 is too low, the liquid nitrogen will freeze at the pipe mouth of the liquid nitrogen injection pipe 4, thereby causing insufficient delivery pressure. If the pressure is too high, it is easy to cause an accident.

[0031] Specifically, if Figure 1 As shown, the top of the tank body 1 is an arc cover structure, the middle is a barrel-shaped structure, and the bottom is a V-shaped structure. The outer surface of the tank body 1 is provided with a heat-insulating layer 7.

[0032] The arc cover structure on the top of the tank body 1 can effectively disperse the pressure and reduce local stress concentration. The V-shaped structure at the bottom can effectively guide the dry ice and realize the smooth discharge of the nitrogen and dry ice mixture.

[0033] The insulation layer 7 is made of insulation material, and rock wool or polyurethane foam can be selected. Rock wool has good thermal insulation performance, a thermal conductivity coefficient of 0.042 to 0.064 W / m·K, high temperature resistance, good fire resistance, high chemical stability, and is not easily affected by environmental factors and aged or damaged. It has a long service life and is suitable for the insulation of carbon dioxide tanks under various working conditions.

[0034] Polyurethane foam has a closed-cell structure, offering excellent insulation, light weight, high specific strength, and easy construction. Its low thermal conductivity effectively prevents heat transfer, maintaining a stable temperature within the CO2 tank. Furthermore, it offers sound insulation, shock absorption, electrical insulation, and resistance to heat, cold, and solvents, making it suitable for tank insulation across a wide range of temperatures.

[0035] Specifically, if Figure 2 As shown, the liquid carbon dioxide injection assembly 2 includes a liquid carbon dioxide delivery main pipeline 201, a liquid carbon dioxide delivery branch pipeline 202 and a liquid carbon dioxide injection pipe 203. Multiple liquid carbon dioxide delivery branch pipelines 202 are symmetrically assembled on the front and rear sides of the liquid carbon dioxide delivery main pipeline 201. The liquid carbon dioxide injection pipe 203 is evenly assembled on the lower side of the outer surface of the liquid carbon dioxide delivery main pipeline 201 and the liquid carbon dioxide delivery branch pipeline 202, and the liquid carbon dioxide injection pipe 203 passes through the top of the tank body 1.

[0036] The portion of the liquid carbon dioxide delivery branch pipe 202 on the liquid carbon dioxide delivery main pipe 201 is in an arc shape corresponding to the arc cover structure of the tank body 1, and the liquid carbon dioxide delivery branch pipe 202 is also in an arc shape corresponding to the arc cover structure of the tank body 1, which can be matched and installed with the tank body 1 more smoothly.

[0037] Specifically, the diameter of the injection end of the liquid carbon dioxide delivery main pipeline 201 is larger than the diameter of the tail end, which improves the stability of the flow of liquid carbon dioxide in the liquid carbon dioxide delivery main pipeline 201 and the liquid carbon dioxide delivery branch pipeline 202, and ensures that each liquid carbon dioxide injection pipe 203 can stably and evenly flow out liquid carbon dioxide.

[0038] Specifically, if Figure 2 As shown, the liquid carbon dioxide injection pipes 203 are thin tubes, and the liquid carbon dioxide injection pipes 203 are evenly distributed in a square matrix.

[0039] The liquid carbon dioxide injection pipe 203 is set as a thin tube, and its specific diameter is set according to actual conditions. The purpose is to allow the liquid carbon dioxide to flow out in the form of a thin stream. Under the action of gravity acceleration, the thin stream will break into droplets in the tank body 1 and fall into the lower area of the tank body 1.

[0040] The square lattice distribution allows the liquid carbon dioxide to fall in the form of rain, allowing it to be evenly cooled and eventually frozen into granular, powdered or snowflake-like dry ice.

[0041] Regarding the design of the liquid carbon dioxide injection assembly 2, the liquid carbon dioxide delivery branch pipe 202 can also be set as a circular pipe to form a plurality of concentric circular liquid carbon dioxide delivery branch pipes 202. The liquid carbon dioxide injection pipe 203 is evenly arranged on each liquid carbon dioxide delivery branch pipe 202 to achieve uniform injection of liquid carbon dioxide.

[0042] In addition, the liquid carbon dioxide delivery main pipeline 201 can be set into a spiral shape, the liquid carbon dioxide delivery branch pipeline 202 can be eliminated, and the liquid carbon dioxide injection pipe 203 can be evenly set on the lower side of the outer surface of the liquid carbon dioxide delivery main pipeline 201 to achieve uniform injection of liquid carbon dioxide.

[0043] Specifically, if Figure 1 As shown, the nitrogen injection assembly 3 includes a nitrogen delivery pipeline 301 and a nitrogen injection pipe 302. Multiple nitrogen injection pipes 302 are evenly arranged on the lower side of the outer surface of the nitrogen delivery pipeline 301, and the nitrogen injection pipes 302 pass through the top of the tank body 1. The nitrogen injection pipes 302 and the liquid carbon dioxide injection pipes 203 are staggered.

[0044] The design of the position of the nitrogen injection pipe 302 allows it to evenly enter the upper space of the tank body 1, ensuring temperature balance in all parts of the upper space of the tank body 1.

[0045] The nitrogen gas source of the nitrogen injection assembly 3 can come from a liquid nitrogen tanker, and the liquid nitrogen can be gasified and heated to a desired temperature by electric heating means.

[0046] Specifically, if Figure 1 As shown, the monitoring component includes a first temperature sensor 10, a pressure sensor 11 and a second temperature sensor 12. The first temperature sensor 10 and the pressure sensor 11 are both arranged on the upper side of the outer surface of the tank body 1, and the second temperature sensor 12 is arranged on the lower side of the outer surface of the tank body 1. The first temperature sensor 10 is used to monitor the temperature of the upper area inside the tank body 1, the pressure sensor 11 is used to monitor the pressure inside the tank body 1, and the second temperature sensor 12 is used to monitor the temperature of the lower area inside the tank body.

[0047] The first temperature sensor 10 monitors the temperature of the upper area inside the tank body 1 , and then controls the control valve of the nitrogen injection assembly 3 to maintain the temperature of the upper area inside the tank body 1 .

[0048] The pressure sensor 11 monitors the pressure in the tank body 1 and controls the opening of the regulating valve 5 to control the pressure in the tank body 1 within a certain range, so as to prevent the hydraulic carbon dioxide from vaporizing in the tank body 1 when the pressure is too low, and to prevent the liquid nitrogen from vaporizing and freezing the liquid nitrogen injection pipe 4 at the inlet when the liquid nitrogen enters the tank body 1.

[0049] The second temperature sensor 12 monitors the temperature of the lower area of the tank body 1, and then controls and adjusts the injection amount of liquid nitrogen to maintain the temperature of the lower area of the tank body 1 within a reasonable range. If the temperature of the lower area is too high, it will affect the freezing speed of the carbon dioxide droplets and may even cause an ice layer to form at the bottom of the tank. If the temperature is too low, the liquid nitrogen may not vaporize normally.

[0050] Specifically, if Figure 1 As shown, an exhaust valve 8 and a safety valve 9 are provided on the top of the tank body 1.

[0051] The exhaust valve 8 and the safety valve 9 are used to release the gas in the tank body 1 or to remove the gas in the tank body 1 to prevent accidents.

[0052] The working principle of the liquid nitrogen and liquid carbon dioxide mixing device is:

[0053] Liquid carbon dioxide flows into the tank body 1 through the liquid carbon dioxide injection assembly 2 and flows out of the liquid carbon dioxide injection pipe 203 in the form of a thin stream. Under the action of gravity acceleration, the thin stream will gradually break into droplets and fall into the lower area of the tank body 1.

[0054] Nitrogen is injected into the upper area of the tank body 1 through the nitrogen injection assembly 3. Since the temperature in the upper area of the tank body 1 is too low, carbon dioxide may freeze and block the liquid carbon dioxide injection pipe 203, and too high a temperature may cause the liquid carbon dioxide to vaporize. Therefore, the temperature of the injected nitrogen is required to be lower than the critical temperature of liquid carbon dioxide, which is 31.2°C, and the corresponding critical pressure is 7.38 MPa, and higher than the critical temperature of solid carbon dioxide, which is -78.5°C. In addition, the critical temperature of liquid carbon dioxide is 31.2°C, and the corresponding critical pressure is 7.38 MPa. The liquefaction pressure decreases with decreasing temperature. Due to the pressure bearing capacity of the tank body, the temperature of the injected nitrogen needs to be closer to -78.5°C.

[0055] Since nitrogen is lighter and has a higher temperature than carbon dioxide, it can maintain a higher temperature in the upper area of the tank 1;

[0056] Liquid nitrogen is injected into the lower area of the tank 1 and vaporizes into nitrogen gas, forming a low-temperature zone. Carbon dioxide droplets falling into the low-temperature zone quickly transform into hailstones or snowflakes of dry ice, which then fall to the bottom of the tank. Heat is released to vaporize the liquid nitrogen, forming a mixture of nitrogen gas and granular dry ice at the bottom of the tank 1. Since the temperature of liquid nitrogen is between -196.56°C and -209°C, much lower than the temperature of liquid carbon dioxide, the droplets of liquid carbon dioxide quickly transform into dry ice particles.

[0057] Since the heat released by converting a unit mass of liquid carbon dioxide into dry ice is basically the same as the heat absorbed by vaporizing a unit mass of liquid nitrogen, the ratio of the injection amount of liquid nitrogen to the injection amount of liquid carbon dioxide is basically 1:1;

[0058] Finally, a mixture of nitrogen and dry ice is formed at the bottom of the tank 1 and is discharged and collected through the output pipe 6;

[0059] When cooling the high-temperature points in the goaf, a mixture of nitrogen and dry ice is released. The dry ice vaporizes and absorbs heat, which can effectively achieve cooling. At the same time, nitrogen has a lower density and diffuses to the higher parts of the goaf, while carbon dioxide has a higher density and diffuses to the lower parts of the goaf, forming a three-dimensional diffusion. This can overcome the problem of limited diffusion direction of a single gas. In addition, since the production process of the nitrogen and dry ice mixture does not require electric heating for vaporization, the power consumption is very low.

[0060] The above content is only a preferred embodiment of the present invention. For ordinary technicians in this field, according to the concept of the present invention, many changes can be made in the specific implementation method and application scope. As long as these changes do not deviate from the concept of the present invention, they all fall within the scope of protection of the present invention.

Claims

1. A device for mixing liquid nitrogen and liquid carbon dioxide, characterized in that: It includes a tank body, a liquid carbon dioxide injection assembly, a nitrogen injection assembly, a liquid nitrogen injection pipe and a monitoring assembly. The output ends of the liquid carbon dioxide injection assembly and the nitrogen injection assembly are both plugged into the top of the tank body. The liquid carbon dioxide injection assembly is used to uniformly inject liquid carbon dioxide droplets into the tank body. The liquid nitrogen injection pipe is plugged and assembled on the lower side of the outer surface of the tank body. The monitoring assembly is assembled on the outer surface of the tank body and is used to monitor the temperature and pressure in the tank body. The lower end of the tank body is equipped with a regulating valve, and the lower end of the regulating valve is equipped with an output pipe; The liquid carbon dioxide injection assembly includes a liquid carbon dioxide delivery main pipeline, a liquid carbon dioxide delivery branch pipeline, and a liquid carbon dioxide injection pipe. The multiple liquid carbon dioxide delivery branch pipelines are symmetrically installed on the front and rear sides of the liquid carbon dioxide delivery main pipeline. The liquid carbon dioxide injection pipes are evenly installed on the lower side of the outer surface of the liquid carbon dioxide delivery main pipeline and the liquid carbon dioxide delivery branch pipelines, and the liquid carbon dioxide injection pipes pass through the top of the tank body. The liquid carbon dioxide injection tubes are thin tubes, and the liquid carbon dioxide injection tubes are evenly distributed in a square matrix; Liquid carbon dioxide flows into the tank through the liquid carbon dioxide injection assembly and flows out of the liquid carbon dioxide injection pipe in the form of a thin stream. Under the acceleration of gravity, the thin stream will gradually break into droplets and fall into the lower area of the tank. In the upper area of the tank, nitrogen is injected through the nitrogen injection assembly to a temperature close to -78.5°C. In the lower area of the tank, liquid nitrogen is injected and vaporized into nitrogen gas, forming a low-temperature zone. After carbon dioxide droplets fall into the low-temperature zone, they quickly transform into hailstones or snowflakes of dry ice, which then fall to the bottom of the tank and release heat to vaporize the liquid nitrogen. A mixture of nitrogen gas and granular dry ice forms at the bottom of the tank, which is then discharged and collected through the output pipe. The ratio of liquid nitrogen injection to liquid carbon dioxide injection is 1:

1.

2. The liquid nitrogen and liquid carbon dioxide mixing device according to claim 1, characterized in that: The top of the tank body is an arc cover structure, the middle part is a barrel-shaped structure, and the bottom is a V-shaped structure. The outer surface of the tank body is provided with a heat-insulating layer.

3. The liquid nitrogen and liquid carbon dioxide mixing device according to claim 1, characterized in that: The diameter of the injection end of the liquid carbon dioxide delivery main pipeline is larger than the diameter of the tail end.

4. The liquid nitrogen and liquid carbon dioxide mixing device according to claim 1, characterized in that: The nitrogen injection assembly includes a nitrogen delivery pipeline and a nitrogen injection pipe. Multiple nitrogen injection pipes are evenly arranged on the lower side of the outer surface of the nitrogen delivery pipeline, and the nitrogen injection pipes pass through the top of the tank body. The nitrogen injection pipes and the liquid carbon dioxide injection pipes are staggered.

5. The liquid nitrogen and liquid carbon dioxide mixing device according to claim 1, characterized in that: The monitoring component includes a first temperature sensor, a pressure sensor and a second temperature sensor. The first temperature sensor and the pressure sensor are both arranged on the upper side of the outer surface of the tank body, and the second temperature sensor is arranged on the lower side of the outer surface of the tank body. The first temperature sensor is used to monitor the temperature of the upper area inside the tank body, the pressure sensor is used to monitor the pressure inside the tank body, and the second temperature sensor is used to monitor the temperature of the lower area inside the tank body.

6. The liquid nitrogen and liquid carbon dioxide mixing device according to claim 1, characterized in that: An exhaust valve and a safety valve are provided on the top of the tank body.

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