Cold trap device for generating high pressure in situ

Abstract

The invention 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] This invention relates to the field of refrigeration technology, and in particular to a cold trap device for generating high pressure in situ. Background Technology

[0002] A cold trap is a device that condenses gas into a liquid or solid. Its main function is to capture gas by condensation on a cooled surface. It is typically placed between a vacuum container and a pump as a device for adsorbing gases or capturing oil vapors. In short, a cold trap is a device that reduces the partial pressure of harmful components in a gas and vapor mixture using 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 path of a cryostat to filter and purify its circulating working fluid; it can also be installed in the pipeline between the vacuum pump inlet and the vacuum chamber to prevent backflow of vapors and pyrolysis products from contaminating the chamber, while also preventing water vapor in the vacuum chamber from affecting the lifespan of the vacuum pump.

[0004] Based on the cooling method, cold traps can be divided into self-cooling cold traps and externally cooled cold traps. Liquid nitrogen cold traps, as a type of externally cooled cold trap, utilize liquid nitrogen for cooling and are commonly used in the piping of cryogenic thermostats to absorb leaked dirty gases and solid particles. Furthermore, based on the material, cold traps can also be divided into metal cold traps and glass cold traps. Metal cold traps are resistant to low temperatures and can withstand high pressures, while glass cold traps are often used in applications requiring optical observation or visualization.

[0005] Despite the wide application and significant effects of cold traps in vacuum systems, several technical challenges remain to be addressed: the internal pressure of a cold trap currently depends primarily on the inlet pressure and cannot be autonomously controlled. For example, conventional glass cold traps can only be used at atmospheric pressure, with their internal pressure matching that of the inlet pipe; while metal cold traps, although capable of withstanding high pressures, cannot autonomously generate pressures exceeding those of the inlet pipe. Summary of the Invention

[0006] This application is made in response to the aforementioned technical problems and aims to overcome the shortcomings of the prior art through innovative solutions.

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

[0008] The cold trap barrel is a hollow, sealed structure placed inside a liquid nitrogen Dewar. Activated carbon is provided at the bottom of the cold trap barrel to capture and filter gases.

[0009] An air inlet pipe extends from the top of the cold trap barrel to the bottom of the cold trap barrel, and is used to allow gas to enter the bottom of the cold trap barrel.

[0010] An exhaust pipe extends from the top of the cold trap barrel into the upper part of the cold trap barrel, and is used to allow gas to be discharged from the cold trap barrel.

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

[0012] A vacuum valve for the gas outlet pipe is provided on the gas outlet pipe located outside the cold trap barrel and is used to control the gas output.

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

[0014] As a further improvement of this application, it also includes a liquid nitrogen pipeline, which is located outside the cold trap barrel and at the upper part of the cold trap barrel, and the horizontal position of the port of the gas outlet pipe inside the cold trap barrel is within the range of the liquid nitrogen pipeline.

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

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

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

[0018] As a further improvement of this application, the connection between the air inlet vacuum valve and the air inlet is by welding or interface connection, the connection between the air outlet vacuum valve and the air outlet is by welding or interface connection, and the connection between the pressure gauge and the air outlet or the air inlet is by welding or interface connection.

[0019] As a further improvement of this application, a first vacuum-sealed interface is provided at the port of the inlet pipe connecting to external gas, and a second vacuum-sealed interface is provided at the port of the outlet pipe outputting gas to the outside. Preferably, the first vacuum-sealed interface can be any one of a vacuum quick-connect self-locking interface, a VCR interface, a ferrule sealing interface, etc., and the second vacuum-sealed interface can be any one of a vacuum quick-connect self-locking interface, a VCR interface, a ferrule sealing interface, etc.

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

[0021] As a further improvement of this application, a control device is also included, which is electrically connected to the inlet pipe vacuum valve, the outlet pipe vacuum valve, and the pressure gauge.

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

[0023] The beneficial effects of this application are as follows:

[0024] This application provides a cold trap device for generating high pressure in situ, including a cold trap barrel, an inlet pipe, an inlet pipe vacuum valve, an outlet pipe, an outlet pipe vacuum valve, and a pressure gauge. The cold trap barrel is placed inside a liquid nitrogen Dewar. The low temperature of the liquid nitrogen Dewar keeps the inside of the cold trap barrel at a low temperature, which can compress or liquefy 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 and thus achieving the pressurization effect.

[0025] The technical solution of this application can generate high pressure in situ for the circulating working fluid without introducing other impurities or requiring additional energy input, thus achieving efficient pressurization, which not only reduces energy consumption but also improves the overall efficiency of the system. Attached Figure Description

[0026] Figure 1 This is a schematic front view of the cold trap device for generating high pressure in situ according to this application.

[0027] Figure 2 A top view schematic diagram of the cold trap device for generating high pressure in situ according to this application;

[0028] Figure 3 A cross-sectional schematic diagram of the cold trap device for generating high pressure in situ according to this application;

[0029] Figure 4 This is a schematic diagram of the pressurization device structure of the helium-3 melting pressure thermometer in Example 1;

[0030] Figure 5This is a schematic diagram of the pressurization device structure of the condensation circuit of the dilution refrigerator in Example 2.

[0031] In the diagram: 1. Cold trap barrel; 2. Inlet pipe; 3. Outlet pipe; 4. Inlet pipe vacuum valve; 5. Outlet pipe vacuum valve; 6. Pressure gauge; 7. Liquid nitrogen pipeline; 8. Liquid nitrogen pipeline inlet; 9. Liquid nitrogen pipeline outlet; 10. Activated carbon. Detailed Implementation

[0032] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0033] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to specific embodiments.

[0034] This application provides a cold trap device for generating high pressure in situ, such as... Figure 1-3 As shown, it includes:

[0035] The cold trap barrel 1 is a hollow, sealed structure placed inside a liquid nitrogen Dewar. Activated carbon 10 is provided at the bottom of the interior of the cold trap barrel 1 for capturing and filtering gases.

[0036] The air inlet pipe 2 extends from the top of the cold trap barrel 1 to the bottom of the cold trap barrel 1, and is used to allow gas to enter the bottom of the cold trap barrel 1.

[0037] The gas outlet pipe 3 extends from the top of the cold trap barrel 1 into the upper part of the cold trap barrel 1, and is used to discharge gas from the cold trap barrel 1.

[0038] Inlet pipe vacuum valve 4, which is located on the inlet pipe 2 outside the cold trap barrel 1, is used to control the entry of gas;

[0039] Vacuum valve 5 for gas outlet pipe, which is located on the gas outlet pipe 3 outside the cold trap barrel 1, is used to control the gas output;

[0040] Pressure gauge 6 is located on the outlet pipe 3 or the inlet pipe 2 outside the cold trap barrel 1, and is located between the inlet pipe vacuum valve 4 and the cold trap barrel 1, or between the outlet pipe vacuum valve 5 and the cold trap barrel 1, for measuring the gas pressure inside the cold trap barrel 1.

[0041] Based on the above technical solution, when the in-situ high-pressure cold trap device is working normally, the vacuum valve 5 of the outlet pipe 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 inside the liquid nitrogen Dewar, the temperature is low, and the gas continuously contracts or liquefies due to the low temperature. When the pressure inside the cold trap barrel 1 is consistent with the pressure at the inlet pipe 2, the vacuum valve 4 of the inlet pipe is closed. The activated carbon 10 can absorb the impurity particles and impurity gas in the contracted or liquefied gas. The cold trap barrel 1 is slowly removed from the liquid nitrogen Dewar. During the removal process, the cold trap barrel 1 gradually heats up, and the gas inside the cold trap barrel 1 also heats up and expands, increasing the pressure inside the cold trap barrel 1. The pressure gauge 6 can read the gas pressure inside the cold trap barrel 1. When the pressure reaches the preset value, the vacuum valve 5 of the outlet pipe is opened, which can realize the pressurization and filtration of 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] In this system, gas enters the cold trap chamber 1 through a pressure difference. For example, if the cold trap chamber 1 is located at the rear end of a 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 chamber 1 and the inlet pipe 2 can be adjusted according to the application environment. By controlling the pressure difference between the cold trap chamber 1 and the inlet pipe 2, the amount of gas entering the cold trap chamber 1 can be controlled, and the pressure at the outlet pipe 3 can be controlled by adjusting the heating temperature. Furthermore, for applications requiring higher pressure at the outlet pipe 3, the number of cold trap devices connected in series can be set to adjust the final pressure at the outlet pipe 3. The more cold trap devices connected in series, the greater the degree of gas pressurization.

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

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

[0045] In an optional implementation, both the inlet pipe 2 and the outlet pipe 3 are welded to the cold trap body 1. Preferably, the welding process is any one of silver soldering, argon arc welding, or vacuum brazing. Welding the inlet pipe 2 and the outlet pipe 3 to the cold trap body 1 enhances the sealing and stability of the connection, reducing the risk of gas leakage. Multiple welding process options are provided, including silver soldering, argon arc welding, and vacuum brazing, all of which ensure weld strength and sealing, improving the quality and reliability of the device.

[0046] In an optional implementation, the connection between the intake pipe vacuum valve 4 and the intake pipe 2 is either welding or interface connection. The interface connection can use any one of the following: a VCR interface, a compression fitting seal interface, etc. Similarly, the connection between the outlet pipe vacuum valve 5 and the outlet pipe 3 is either welding or interface connection. The interface connection can use any one of the following: a VCR interface, a compression fitting seal interface, etc. The connection between the pressure gauge 6 and the outlet pipe 3 or the intake pipe 2 is either welding or interface connection. The interface connection can use any one of the following: a VCR interface, a compression fitting seal interface, etc. Multiple connection methods are provided, including welding and interface connections. These connection methods are flexible and diverse, ensuring both sealing performance and ease of component replacement and maintenance.

[0047] In an optional implementation, the port of the inlet pipe connecting to external gas is provided with a first vacuum-sealed interface, and the port of the outlet pipe 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-connect self-locking interface, a VCR interface, a compression fitting interface, etc., and the second vacuum-sealed interface can be any one of a vacuum quick-connect self-locking interface, a VCR interface, a compression fitting interface, etc. The vacuum-sealed interfaces connecting the ports of the inlet pipe 2 and the outlet pipe 3 can have various options, including vacuum quick-connect self-locking interfaces, VCR interfaces, and compression fitting interfaces. These interface designs make connection to external devices more convenient and reliable.

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

[0049] In an optional implementation, a control device is also included, which 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 it to the inlet pipe vacuum valve 4, the outlet pipe vacuum valve 5, and the pressure gauge 6, automated control and monitoring of the gas pressure inside the device are achieved, improving the convenience and accuracy of operation.

[0050] In an optional implementation, a pressure relief valve is also included. This valve is located on the outlet pipe 3 or the inlet pipe 2 between the pressure gauge 6 and the cold trap body 1, and is electrically connected to the control device. By adding the pressure relief valve and connecting it to the control device, the valve automatically opens to release pressure when the gas pressure inside the device exceeds a set value, ensuring the 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, as detailed below:

[0052] Example 1

[0053] A cold trap device that generates high pressure in situ is used to pressurize a helium-3 melting pressure thermometer. Two such cold trap devices are connected in series in the room temperature tubing of the helium-3 melting pressure thermometer. A schematic diagram of the pressurization device for the helium-3 melting pressure thermometer is shown below. Figure 4 As shown. During the pressurization process: 1. First, close the vacuum valve 5 of the outlet pipe of cold trap device A and continuously introduce helium-3 gas into the interior of cold trap A, then close the vacuum valve of the inlet pipe 2 of cold trap device A; 2. Next, introduce liquid nitrogen into the liquid nitrogen pipeline 7 surrounding the outer wall of cold trap device A, and then slowly remove the entire cold trap device A from the liquid nitrogen Dewar; 3. During the removal process, read the pressure of the cold trap barrel 1 of cold trap device A through pressure gauge 6; when the pressure reaches the required 15 bar, close the vacuum valve 5 of the outlet pipe of cold trap device B, then open the vacuum valve 5 of the outlet pipe of cold trap device A, and introduce helium-3 gas into the cold trap of 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-3 gas into 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 through the pressure gauge 6; when the pressure reaches the required 30 bar, then open the vacuum valve 5 of the outlet pipe of the cold trap device B and inject high-pressure helium-3 gas into the melting pressure thermometer.

[0054] Example 2

[0055] A high-pressure cold trap device is used in situ to pressurize the condenser circuit of a dilution refrigerator. This cold trap device replaces the conventional cold trap in the dilution refrigerator. The main pressurizing gas is a mixture of liquefied helium-3 and helium-4. A schematic diagram of the pressurization device for the condenser circuit of the dilution refrigerator is shown below. 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 vacuum valve 5 of the cold trap device's outlet pipe, and continuously introduce helium-3 and helium-4 gas into the cold trap barrel 1 of the cold trap device, then close the vacuum valve 4 of the inlet pipe; 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, and 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 through the pressure gauge 6; when the pressure reaches 2.5 bar, open the vacuum valve 5 of the outlet pipe, 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 in this application is as follows: Helium can remain in a gaseous state even at absolute zero, and it can only solidify under extremely low temperature and high pressure. In order to produce solid helium, a pressure of more than 25 atmospheres needs to be applied to the cryogenic experimental device. This cold trap device can be used as a pre-pressurization and filtration device. When the cryogenic experimental device is at a suitable temperature, it can be pressurized: First, close the vacuum valve 5 of the cold trap device's outlet pipe 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 vacuum valve 4 of the inlet pipe; second, 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 entire cold trap barrel 1 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 vacuum valve 5 of the outlet pipe and introduce filtered high-pressure gas into the liquid helium pressurization device at the rear end to continue the next pressurization step.

[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 related inlet pipe vacuum valve 4, outlet pipe vacuum valve 5 and pressure gauge 6. The innovation of this device lies in its ability to utilize the low-temperature environment created by 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 inside the liquid nitrogen Dewar, its internal temperature drops significantly. This cryogenic condition allows the gas entering the cold trap barrel 1 to be compressed or converted 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, thus generating higher pressure. This process is entirely completed inside the device and is therefore called "in-situ" pressurization.

[0059] The significant advantage of this technical solution lies in its ability to achieve efficient pressurization of the working fluid without introducing external impurities or requiring additional energy input. This method not only helps reduce energy consumption and improve environmental performance but also significantly enhances the overall system efficiency. In short, the cold trap device of this invention cleverly utilizes temperature changes to control gas pressure, providing a novel, efficient, and environmentally friendly pressurization solution for the industrial sector.

[0060] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0061] The detailed descriptions listed above are merely specific descriptions of feasible implementation methods of this application and are not intended to limit the scope of protection of this application. All equivalent implementation methods or modifications made without departing from the spirit of the art of this application should be included within 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 is a hollow, sealed structure placed inside a liquid nitrogen Dewar. Activated carbon is provided at the bottom of the cold trap barrel to capture and filter gases. An air inlet pipe extends from the top of the cold trap barrel to the bottom of the cold trap barrel, for allowing gas to enter the bottom of the cold trap barrel; An exhaust pipe extends from the top of the cold trap barrel into the upper part of the cold trap barrel, and is used to allow gas to be discharged from the cold trap barrel. An inlet pipe vacuum valve is provided on the inlet pipe located outside the cold trap barrel and is used to control the entry of gas. A vacuum valve for the gas outlet pipe is provided on the gas outlet pipe located outside the cold trap barrel and is used to control the gas output. A pressure gauge is installed on the outlet pipe or the inlet pipe outside the cold trap barrel, and is located between the inlet pipe vacuum valve and the cold trap barrel, or between the outlet pipe vacuum valve and the cold trap barrel, for measuring the gas pressure inside the cold trap barrel.

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 located outside the cold trap barrel and at the top of the cold trap barrel. The horizontal position of the port of the gas outlet pipe inside 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 is equipped with a flange cover, and the inlet and outlet of the liquid nitrogen pipeline are both located on the flange cover of the cold trap barrel.

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 by welding process.

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

6. The in-situ high-pressure cold trap device according to claim 1, characterized in that, The connection between the air inlet vacuum valve and the air inlet is by welding or interface connection; the connection between the air outlet vacuum valve and the air outlet is by welding or interface connection; and the connection between the pressure gauge and the air outlet or the air inlet is by welding or interface connection.

7. The in-situ high-pressure cold trap device according to claim 1, characterized in that, The port of the inlet pipe that connects to the external gas is provided with a first vacuum sealing interface, which is any one of a vacuum quick-connect self-locking interface, a VCR interface, or a ferrule sealing interface. The port of the outlet pipe that outputs gas to the outside is provided with a second vacuum sealing interface, which is any one of a vacuum quick-connect self-locking interface, a VCR interface, or 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 cold trap device for generating high pressure in situ according to claim 1, characterized in that, It also includes a control device, which is electrically connected to the inlet vacuum valve, the outlet vacuum valve, and a 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 located on the outlet pipe or the inlet pipe between the pressure gauge and the cold trap body, and is electrically connected to the control device.

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