Cold trap device capable of generating high pressure in situ

Abstract

The utility model relates to a cold trap device capable of generating high pressure in situ, which comprises a cold trap barrel body, an air inlet pipe, an air inlet pipe vacuum valve, an air outlet pipe, an air outlet pipe vacuum valve and a pressure gauge, and is characterized in that the cold trap barrel body is arranged in a liquid nitrogen Dewar; the device can utilize a low-temperature environment created by the liquid nitrogen Dewar to form a low-temperature space capable of effectively compressing or liquefying gas in the cold trap barrel body, so that the gas entering the cold trap barrel body is compressed or converted into a liquid state, and the internal temperature of the gas gradually rises along with the slow removal of the cold trap barrel body from the liquid nitrogen environment; the previously compressed or liquefied gas begins to expand, creating a higher pressure. External impurities are not introduced, extra energy input is not needed, energy consumption is reduced, the environmental protection performance is improved, and the operation efficiency of the whole system can be remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of refrigeration technology, and in particular to a cold trap device for generating high pressure in situ. Background Art

[0002] A cold trap is a device that condenses gases into liquids or solids. Its primary function is to capture gases by condensation on a cooled surface. It is typically placed between a vacuum container and a pump to adsorb gases or capture oil vapors. Simply put, a cold trap is a device that reduces the partial pressure of harmful components in a gas or vapor mixture through physical or chemical methods. It is also known as a trap.

[0003] Cold traps are commonly used in instruments with continuous gas circulation to filter and purify the circulating gas. For example, a cold trap can be installed in the gas line of a cryostat to filter and purify the circulating working fluid. They can also be installed in the pipeline between the vacuum pump inlet and the vacuum chamber to prevent backflow of steam and pyrolysis products from contaminating the chamber, while also preventing water vapor in the vacuum chamber from affecting the life of the vacuum pump.

[0004] Cold traps can be categorized as self-cooling or externally cooled, depending on the cooling method. Liquid nitrogen cold traps, a type of externally cooled cold trap, utilize liquid nitrogen for cooling and are commonly used in cryostat piping to absorb leaked dirty air and solid particles. Furthermore, cold traps can be categorized as metal or glass, depending on the material. Metal cold traps are cryogenically resistant and can withstand high pressures, while glass cold traps are often used in applications requiring optical observation or visualization.

[0005] Despite their widespread application and remarkable effectiveness in vacuum systems, cold traps still face several technical challenges. Currently, the internal pressure of a cold trap depends primarily on the incoming air pressure and cannot be independently regulated. For example, conventional glass cold traps can only be used at ambient pressure, with their internal pressure being the same as the inlet pressure. Metal cold traps, while capable of withstanding high pressures, cannot independently generate pressures higher than that of the inlet pipe. Summary of the Invention

[0006] This application is proposed based on the above technical problems and aims to overcome the deficiencies in the existing technology through innovative solutions.

[0007] To solve the above technical problems, the present application provides a cold trap device for generating high pressure in situ, comprising:

[0008] The cold trap barrel body is a hollow sealed structure placed in a liquid nitrogen dewar. Activated carbon is provided at the bottom of the cold trap barrel body for capturing and filtering gas.

[0009] An air inlet pipe, extending from the top of the cold trap barrel into the bottom of the cold trap barrel, for allowing gas to enter the bottom of the cold trap barrel;

[0010] An air outlet pipe extends from the top of the cold trap barrel into the upper part of the cold trap barrel, and is used to discharge gas from the cold trap barrel;

[0011] An air inlet pipe vacuum valve is provided on the air inlet pipe outside the cold trap barrel and is used to control the entry of gas;

[0012] An outlet pipe vacuum valve is provided on the outlet pipe outside the cold trap barrel to control the output of gas;

[0013] A pressure gauge is provided on the air outlet pipe or the air inlet pipe outside the cold trap barrel body, and is located between the air inlet pipe vacuum valve and the cold trap barrel body, or between the air outlet pipe vacuum valve and the cold trap barrel body, for measuring the gas pressure inside the cold trap barrel body.

[0014] As a further improvement of the present application, it further includes a liquid nitrogen pipeline, which is arranged outside the cold trap barrel and located at the upper part of the cold trap barrel. The horizontal position of the port of the air outlet pipe in the cold trap barrel is within the range of the liquid nitrogen pipeline.

[0015] As a further improvement of the present application, a flange cover is provided on the cold trap barrel body, and the inlet and the outlet of the liquid nitrogen pipeline are both provided on the flange cover of the cold trap barrel body.

[0016] As a further improvement of the present application, the air inlet pipe and the air outlet pipe are all welded to the cold trap barrel.

[0017] As a further improvement of the present application, the welding process is any one of silver welding, argon arc welding, and vacuum brazing.

[0018] As a further improvement of the present application, the connection method between the intake pipe vacuum valve and the intake pipe is welding or interface connection, the connection method between the outlet pipe vacuum valve and the outlet pipe is welding or interface connection, and the connection method between the pressure gauge and the outlet pipe or the intake pipe is welding or interface connection.

[0019] As a further improvement of the present application, the port of the air inlet pipe connected to the external gas is provided with a first vacuum sealing interface, and the port of the air outlet pipe for outputting gas to the outside is provided with a second vacuum sealing interface. Preferably, the first vacuum sealing interface can be any one of a vacuum quick-plug self-locking interface, a VCR interface, a ferrule sealing interface, etc., and the second vacuum sealing interface can be any one of a vacuum quick-plug self-locking interface, a VCR interface, a ferrule sealing interface, etc.

[0020] As a further improvement of the present application, the cold trap barrel is made of stainless steel.

[0021] As a further improvement of the present application, it further includes a control device, which is electrically connected to the intake pipe vacuum valve, the outlet pipe vacuum valve and the pressure gauge.

[0022] As a further improvement of the present application, a pressure relief valve is further included, which is arranged on the air outlet pipe or the air inlet pipe between the pressure gauge and the cold trap barrel and is electrically connected to the control device.

[0023] The beneficial effects of this application are:

[0024] The present application provides a cold trap device for generating high pressure in situ, comprising a cold trap barrel, an air inlet pipe, an air inlet pipe vacuum valve, an air outlet pipe, an air outlet pipe vacuum valve and a pressure gauge. The cold trap barrel is placed in a liquid nitrogen dewar. The low temperature of the liquid nitrogen dewar is utilized to maintain a lower temperature inside the cold trap barrel, thereby compressing or liquefying the gas entering the cold trap barrel. When the cold trap barrel is slowly removed from the liquid nitrogen dewar, the gas inside the cold trap barrel expands, increasing its pressure, thereby achieving a pressurization effect.

[0025] The technical solution of the present application can generate high pressure in the circulating working fluid in situ without introducing other impurities or requiring additional energy input, thereby achieving efficient pressurization, which not only reduces energy consumption but also improves the overall efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the main structure of the in-situ high-pressure cold trap device of the present application;

[0027] Figure 2 This is a schematic top view of the structure of the in-situ high-pressure cold trap device of the present application;

[0028] Figure 3 This is a schematic cross-sectional view of the cold trap device for generating high pressure in situ according to the present application;

[0029] Figure 4 Schematic diagram of the structure of the pressurizing device of the helium-3 melting pressure thermometer of Example 1;

[0030] Figure 5This is a schematic structural diagram of the pressurizing device of the condensing circuit of the dilution refrigerator of Example 2.

[0031] In the figure: 1. Cold trap barrel; 2. Air inlet pipe; 3. Air outlet pipe; 4. Air inlet pipe vacuum valve; 5. Air outlet pipe vacuum valve; 6. Pressure gauge; 7. Liquid nitrogen pipeline; 8. Inlet of liquid nitrogen pipeline; 9. Outlet of liquid nitrogen pipeline; 10. Activated carbon. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with specific implementation methods.

[0034] The present application provides a cold trap device for generating high pressure in situ, such as Figure 1-3 Shown, including:

[0035] A cold trap barrel 1, which is a hollow sealed structure and is placed in a liquid nitrogen dewar. Activated carbon 10 is provided at the bottom of the cold trap barrel 1 for capturing and filtering gas.

[0036] An air inlet pipe 2, extending from the top of the cold trap barrel 1 into the bottom of the cold trap barrel 1, for allowing gas to enter the bottom of the cold trap barrel 1;

[0037] An air outlet pipe 3 extends from the top of the cold trap barrel 1 into the upper part of the cold trap barrel 1 to discharge gas from the cold trap barrel 1;

[0038] An air inlet pipe vacuum valve 4 is provided on the air inlet pipe 2 outside the cold trap barrel 1 and is used to control the entry of gas;

[0039] An outlet pipe vacuum valve 5 is provided on the outlet pipe 3 outside the cold trap barrel 1 and is used to control the output of gas;

[0040] The pressure gauge 6 is provided on the air outlet pipe 3 or the air inlet pipe 2 outside the cold trap barrel body 1, and is located between the air inlet pipe vacuum valve 4 and the cold trap barrel body 1, or, is located between the air outlet pipe vacuum valve 5 and the cold trap barrel body 1, and is used to measure the gas pressure in the cold trap barrel body 1.

[0041] Based on the above technical solution, when the cold trap device that generates high pressure in situ is working normally, the outlet pipe vacuum valve 5 is first closed, and the gas enters the cold trap barrel 1 from the inlet pipe 2. Because the cold trap barrel 1 is placed in the liquid nitrogen Dewar, the temperature is low, and the gas continues to shrink or liquefy when cooled at low temperature. When the pressure in the cold trap barrel 1 is consistent with the pressure at the inlet pipe 2, the inlet pipe vacuum valve 4 is closed, and the activated carbon 10 can absorb the impurity particles and impurity gases in the shrunken or liquefied gas, and the cold trap barrel 1 is slowly taken out of the liquid nitrogen Dewar. During the removal process, the cold trap barrel 1 gradually heats up, and the gas in the cold trap barrel 1 also heats up and expands, causing the pressure in the cold trap barrel 1 to increase. The pressure gauge 6 can read the gas pressure in the cold trap barrel 1. When the pressure reaches the preset value, the outlet pipe vacuum valve 5 is opened to pressurize and filter the gas. The preset pressure value can be set according to the application scenario of the cold trap device, and the specific value is not limited.

[0042] Among them: the gas enters the cold trap barrel 1 through the pressure difference, such as: the cold trap barrel 1 is placed at the rear end of the mechanical pump, and the pressure at the rear end of the mechanical pump is 0.7 bar, then the maximum filling pressure of the cold trap is 0.7 bar. The pressure difference between the cold trap barrel 1 and the air inlet pipe 2 can be adjusted according to the needs of the application environment. The amount of gas entering the cold trap barrel 1 is controlled according to the pressure difference between the cold trap barrel 1 and the air inlet pipe 2, and then the pressure at the outlet pipe 3 is controlled by adjusting the temperature of the heating. In addition, for application scenarios with a large pressure demand at the outlet pipe 3, the number of cold trap devices in series can also be set to adjust the pressure at the final outlet pipe 3. The more cold trap devices are connected in series, the greater the degree to which the gas is pressurized.

[0043] In an optional embodiment, a liquid nitrogen pipeline 7 is further included. The liquid nitrogen pipeline 7 is provided outside the cold trap barrel 1 and is located at the upper portion of the cold trap barrel 1. The horizontal position of the port of the gas outlet pipe 3 in the cold trap barrel 1 is within the range of the liquid nitrogen pipeline 7. By adding the liquid nitrogen pipeline 7 and locating it at the upper portion of the cold trap barrel 1, liquid nitrogen can be more effectively utilized to cool the cold trap barrel 1, thereby improving the cooling efficiency and performance of the device.

[0044] In an optional embodiment, a flange cover is provided on the cold trap barrel body 1, and the inlet 8 and the outlet 9 of the liquid nitrogen pipeline are both provided on the flange cover of the cold trap barrel body 1. Providing the inlet and outlet of the liquid nitrogen pipeline 7 on the flange cover of the cold trap barrel body 1 simplifies the device structure, facilitates the addition and discharge of liquid nitrogen, and improves operational convenience.

[0045] In an optional embodiment, the air inlet pipe 2 and the air outlet pipe 3 are welded to the cold trap barrel 1. Preferably, the welding process is any one of silver welding, argon arc welding, and vacuum brazing. The use of welding between the air inlet pipe 2 and the air outlet pipe 3 and the cold trap barrel 1 enhances the sealing and stability of the connection and reduces the risk of gas leakage. A variety of welding process options are provided, including silver welding, argon arc welding, and vacuum brazing, all of which can ensure the strength and sealing of the weld, thereby improving the quality and reliability of the device.

[0046] In an optional embodiment, the connection between the inlet pipe vacuum valve 4 and the inlet pipe 2 is by welding or interface connection, wherein the interface used in the interface connection can be any one of a VCR interface, a ferrule sealing interface, etc.; the connection between the outlet pipe vacuum valve 5 and the outlet pipe 3 is by welding or interface connection, wherein the interface used in the interface connection can be any one of a VCR interface, a ferrule sealing interface, etc.; the connection between the pressure gauge 6 and the outlet pipe 3 or the inlet pipe 2 is by welding or interface connection, wherein the interface used in the interface connection can be any one of a VCR interface, a ferrule sealing interface, etc. A variety of connection methods are provided, including welding and interface connection. These flexible and diverse connection methods not only ensure the sealing of the connection but also facilitate the replacement and maintenance of components.

[0047] In an optional embodiment, the port of the air inlet pipe connected to the external gas is provided with a first vacuum-sealed interface, and the port of the air outlet pipe for outputting gas to the outside is provided with a second vacuum-sealed interface. Preferably, the first vacuum-sealed interface can be any one of a vacuum quick-plug self-locking interface, a VCR interface, a ferrule-sealed interface, etc., and the second vacuum-sealed interface can be any one of a vacuum quick-plug self-locking interface, a VCR interface, a ferrule-sealed interface, etc. There are multiple options for the vacuum-sealed interfaces connecting the ports of the air inlet pipe 2 and the air outlet pipe 3, including vacuum quick-plug self-locking interfaces, VCR interfaces, and ferrule-sealed interfaces. These interface designs make connection to external devices more convenient and reliable.

[0048] In an optional embodiment, the cold trap barrel 1 is made of stainless steel. Using stainless steel to prepare the cold trap barrel 1 improves the corrosion resistance and service life of the device, while also ensuring the safety and stability of the device.

[0049] In an optional embodiment, a control device is further included, and the control device is electrically connected to the inlet pipe vacuum valve 4, the outlet pipe vacuum valve 5, and the pressure gauge 6. By adding a control device and electrically connecting the inlet pipe vacuum valve 4, the outlet pipe vacuum valve 5, and the pressure gauge 6, automatic control and monitoring of the gas pressure in the device is achieved, thereby improving the convenience and accuracy of operation.

[0050] In an optional embodiment, a pressure relief valve is further included. The pressure relief valve is disposed on the outlet pipe 3 or the inlet pipe 2 between the pressure gauge 6 and the cold trap barrel 1 and is electrically connected to the control device. The addition of the pressure relief valve and its electrical connection to the control device automatically opens to relieve pressure when the gas pressure within the device exceeds a set value, thereby ensuring safe operation of the device and preventing safety accidents caused by excessive pressure.

[0051] This application also provides application examples of the above-mentioned in-situ high-pressure cold trap device, which are as follows:

[0052] Example 1

[0053] The cold trap device that generates high pressure in situ is used to pressurize the helium-3 melting pressure thermometer. Two cold trap devices are placed in series in the room temperature pipeline of the helium-3 melting pressure thermometer. The structural diagram of the pressurization device of the helium-3 melting pressure thermometer is shown in FIG. Figure 4 As shown. During the pressurization process: 1. First, close the vacuum valve 5 of the outlet pipe of the cold trap device A, and continuously introduce helium-3 gas into the interior of the cold trap A, and then close the vacuum valve of the air inlet pipe 2 of the cold trap device A; 2. Next, introduce liquid nitrogen into the liquid nitrogen pipeline 7 surrounding the outer wall of the cold trap device A, and then slowly remove the cold trap device A from the liquid nitrogen dewar; 3. During the removal process, read the pressure of the cold trap barrel 1 of the cold trap device A through the pressure gauge 6; when the pressure reaches the required 15 bar, close the vacuum valve 5 of the outlet pipe of the cold trap device B, and then open the vacuum valve 5 of the outlet pipe of the cold trap device A, and introduce helium-3 gas into the cold trap of the cold trap device B. 4. Then, close the vacuum valve 4 of the inlet pipe of the cold trap device B and repeat steps 1-3 to continue adding helium trioxide gas to the cold trap barrel 1 of the cold trap device B. 5. Next, introduce liquid nitrogen into the liquid nitrogen pipeline 7 surrounding the outer wall of the cold trap barrel 1 of the cold trap device B, and then slowly remove the entire cold trap device B from the liquid nitrogen dewar. During the removal process, read the pressure inside the cold trap barrel 1 of the cold trap device B using the pressure gauge 6. When the pressure reaches the required 30 bar, open the vacuum valve 5 of the outlet pipe of the cold trap device B and inject high-pressure helium trioxide gas into the melt pressure thermometer.

[0054] Example 2

[0055] The in-situ high-pressure cold trap device is used to pressurize the condensation line of the dilution refrigerator. The cold trap device is used to replace the conventional cold trap in the dilution refrigerator to pressurize the condensation line. The main pressurizing gas is liquefied helium-3-helium-4 mixed gas. The structural diagram of the pressurizing device of the condensation line of the dilution refrigerator is shown in FIG. Figure 5As shown. During the pressurization process: When the dilution refrigerator is preparing to liquefy the Helium-3 and Helium-4 mixture, first close the cold trap device's outlet pipe vacuum valve 5, and continuously introduce Helium-3 and Helium-4 gases into the cold trap barrel 1 of the cold trap device. Then, close the inlet pipe vacuum valve 4. Next, introduce liquid nitrogen into the liquid nitrogen pipeline 7 surrounding the outer wall of the cold trap barrel 1 of the cold trap device. Then, slowly remove the entire cold trap barrel 1 from the liquid nitrogen dewar. During the removal process, read the pressure inside the cold trap barrel 1 using the pressure gauge 6. When the pressure reaches 2.5 bar, open the outlet pipe vacuum valve 5, and inject high-pressure Helium-3 and Helium-4 mixture into the condensation line of the dilution refrigerator to accelerate the liquefaction process.

[0056] The working principle of the cold trap device of the present application is as follows: helium can remain in a gaseous state even at absolute zero, and can only solidify when extremely low temperature and high pressure coexist. In order to produce solid helium, it is necessary to apply a pressure of more than 25 atmospheres to the low-temperature experimental device. The cold trap device can be used as a pre-stage pressurization and filtration device. When the low-temperature experimental device is at an appropriate temperature, it can be pressurized: first, close the outlet pipe vacuum valve 5 of the cold trap device, and continuously introduce helium-3 and / or helium-4 gas into the cold trap barrel 1 of the cold trap device, and then close the inlet pipe vacuum valve 4; secondly, introduce liquid nitrogen into the liquid nitrogen pipeline 7 surrounding the outer wall of the cold trap barrel 1 of the cold trap device, and then slowly remove the cold trap barrel 1 as a whole from the liquid nitrogen dewar; during the removal process, read the pressure inside the cold trap barrel 1 through the pressure gauge 6; when the pressure reaches 2 bar, open the outlet pipe vacuum valve 5, and introduce filtered high-pressure gas into the liquid helium pressurizing device at the rear end to continue the next step of pressurization.

[0057] In summary, this application provides a cold trap device for generating high pressure in situ. Its core components include a cold trap barrel 1, an inlet pipe 2, and an outlet pipe 3 system, as well as associated inlet pipe vacuum valves 4 and 5, and a pressure gauge 6. The innovation of this device lies in its ability to utilize the low-temperature environment created by the liquid nitrogen Dewar to form a space within the cold trap barrel 1 that can effectively compress or liquefy gas.

[0058] Specifically, when the cold trap barrel 1 is placed in the liquid nitrogen dewar, its internal temperature drops significantly. This low temperature compresses or converts the gas entering the cold trap barrel 1 into a liquid state. As the cold trap barrel 1 is slowly removed from the liquid nitrogen environment, its internal temperature gradually rises, and the previously compressed or liquefied gas begins to expand, generating a higher pressure. This process is completed entirely within the device, hence the name "in situ" pressurization.

[0059] A significant advantage of this technical solution is its ability to efficiently pressurize the working fluid without introducing external impurities or requiring additional energy input. The implementation of this method not only helps reduce energy consumption and improve environmental performance, but also significantly improves the operating efficiency of the entire system. In short, the cold trap device of this application cleverly utilizes temperature changes to control gas pressure, providing a novel, efficient, and environmentally friendly pressurization solution for the industrial field.

[0060] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0061] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of this application. They are not intended to limit the scope of protection of this application. Any equivalent implementation methods or changes that do not deviate from the technical spirit of this application should be included in the scope of protection of this application.

Claims

1. A cold trap device for generating high pressure in situ, characterized in that: include: The cold trap barrel body is a hollow sealed structure placed in a liquid nitrogen dewar. Activated carbon is provided at the bottom of the cold trap barrel body for capturing and filtering gas. An air inlet pipe, extending from the top of the cold trap barrel into the bottom of the cold trap barrel, for allowing gas to enter the bottom of the cold trap barrel; An air outlet pipe extends from the top of the cold trap barrel into the upper part of the cold trap barrel, and is used to discharge gas from the cold trap barrel; An air inlet pipe vacuum valve is provided on the air inlet pipe outside the cold trap barrel and is used to control the entry of gas; An outlet pipe vacuum valve is provided on the outlet pipe outside the cold trap barrel to control the output of gas; A pressure gauge is provided on the air outlet pipe or the air inlet pipe outside the cold trap barrel body, and is located between the air inlet pipe vacuum valve and the cold trap barrel body, or between the air outlet pipe vacuum valve and the cold trap barrel body, for measuring the gas pressure inside the cold trap barrel body.

2. The in-situ high-pressure cold trap device according to claim 1, characterized in that: It also includes a liquid nitrogen pipeline, which is arranged outside the cold trap barrel and located at the upper part of the cold trap barrel. The horizontal position of the port of the air outlet pipe in the cold trap barrel is within the range of the liquid nitrogen pipeline.

3. The in-situ high-pressure cold trap device according to claim 2, characterized in that: The cold trap barrel body is provided with a flange cover, and the inlet and the outlet of the liquid nitrogen pipeline are both provided on the flange cover of the cold trap barrel body.

4. The in-situ high-pressure cold trap device according to claim 1, characterized in that: The air inlet pipe and the air outlet pipe are respectively connected to the cold trap barrel through a welding process.

5. The in-situ high-pressure cold trap device according to claim 4, characterized in that: The welding process is any one of silver welding, argon arc welding and vacuum brazing.

6. The in-situ high-pressure cold trap device according to claim 1, characterized in that: The connection method between the intake pipe vacuum valve and the intake pipe is welding or interface connection, the connection method between the outlet pipe vacuum valve and the outlet pipe is welding or interface connection, and the connection method between the pressure gauge and the outlet pipe or the intake pipe is welding or interface connection.

7. The in-situ high-pressure cold trap device according to claim 1, characterized in that: The port of the air inlet pipe connected to the external gas is provided with a first vacuum sealing interface, any one of a vacuum quick-plug self-locking interface, a VCR interface, and a ferrule sealing interface; the port of the air outlet pipe outputting gas to the outside is provided with a second vacuum sealing interface, any one of a vacuum quick-plug self-locking interface, a VCR interface, and a ferrule sealing interface.

8. The in-situ high-pressure cold trap device according to claim 1, characterized in that: The cold trap barrel is made of stainless steel.

9. The in-situ high-pressure cold trap device according to claim 1, characterized in that: It also includes a control device, which is electrically connected to the air inlet pipe vacuum valve, the air outlet pipe vacuum valve and the pressure gauge.

10. The in-situ high-pressure cold trap device according to claim 9, characterized in that: It also includes a pressure relief valve, which is arranged on the air outlet pipe or the air inlet pipe between the pressure gauge and the cold trap barrel, and is electrically connected to the control device.

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