Intelligent high-vacuum super-large-pumping-speed low-temperature pump and vacuum obtaining method thereof

Abstract

The intelligent high-vacuum super-large-pumping-speed low-temperature pump comprises a pump body, a refrigerating system and a control system, the pump body is provided with an adsorption array and a liquid nitrogen shielding shell, the adsorption array is formed by vertically arranging a plurality of adsorption units in parallel, a gap is reserved between every two adjacent adsorption units, and the liquid nitrogen shielding shell is arranged in the liquid nitrogen shielding shell. The adsorption unit comprises a plurality of adsorption cold plates and baffles which are alternately arranged, and adsorbents are arranged on the surfaces of the adsorption cold plates; the refrigerating system comprises a helium refrigerating system and a liquid nitrogen refrigerating system; the helium refrigeration system provides cold energy for the adsorption cold plate; and the liquid nitrogen refrigerating system provides cooling capacity for the baffle and the liquid nitrogen shielding shell. The low-temperature pump solves the technical problems that an existing low-temperature pump is insufficient in pumping speed and vacuum degree, low in intelligent degree, high in energy consumption and large in occupied space. The method can be widely applied to the fields of semiconductors, nuclei, aerospace, pharmacy and the like.

Description

Technical Field

[0001] This invention relates to a cryogenic pump, and more particularly to an intelligent high-vacuum ultra-high pumping speed cryogenic pump and a method for obtaining vacuum. Background Technology

[0002] Currently, domestic cryogenic pumps are mainly concentrated in the low-to-mid-range products, while high-end products rely on imports from American and Japanese companies. From the perspective of current technological development trends, existing cryogenic pump products can no longer fully meet the development needs of new technologies and processes in terms of pumping speed, vacuum level, level of intelligence, pumping capacity, recovery time, regeneration cycle, and energy consumption. This is especially prominent in the semiconductor, nuclear, aerospace, and pharmaceutical industries. With the continuous progress of science and technology, various industries will inevitably place higher demands on cryogenic pumps, and cryogenic pumps will face new innovations and challenges. Summary of the Invention

[0003] This invention addresses the technical problems of existing cryogenic pumps, such as insufficient pumping speed, inadequate vacuum level, low level of intelligence, high energy consumption, and large space occupation. It provides an intelligent high-vacuum ultra-high pumping speed cryogenic pump with significantly improved pumping speed and vacuum level, high level of intelligence, low energy consumption, and small space occupation, as well as a method for obtaining vacuum.

[0004] Therefore, the technical solution of the present invention is an intelligent high-vacuum ultra-high pumping speed cryogenic pump, including a pump body, a refrigeration system and a control system. The pump body is provided with an adsorption array and a liquid nitrogen shielding shell. The adsorption array is composed of multiple adsorption units arranged vertically side by side, with gaps between adjacent adsorption units. The adsorption unit includes multiple alternately arranged adsorption cold plates and baffles, and the surface of the adsorption cold plates is provided with adsorbent. The refrigeration system includes a helium refrigeration system and a liquid nitrogen refrigeration system; the helium refrigeration system provides cooling for the adsorption cold plate; the liquid nitrogen refrigeration system provides cooling for the baffle and the liquid nitrogen shielding shell; The control system is a distributed control system with PLC as its core. It is configured to monitor the pump body temperature and pressure parameters in real time, automatically adjust the operating status of the refrigeration system according to preset thresholds, and execute fault diagnosis and safety protection programs. The control system adopts a triple interlocking mechanism of hardware circuits, programs and operating software to prevent misoperation.

[0005] Preferably, the pump body consists of two units, left and right, which are respectively suspended on both sides of the vacuum chamber with their pump ports facing each other. Each pump body includes an adsorption array consisting of 8 adsorption units. The adsorption cold plate adopts a three-layer V-shaped plate structure, and the baffle adopts an umbrella-shaped baffle. The adsorption cold plate is located behind the umbrella-shaped baffle. The adsorption cold plate and the umbrella-shaped baffle are arranged alternately to form a structure with a wheat ear-shaped cross section.

[0006] Preferably, the pump body adopts an insert-type multi-layer structure and is sealed to the vacuum chamber with a fluororubber sealing ring.

[0007] Preferably, the control system includes a cryogenic pump body control system, a liquid nitrogen refrigeration control system, and a helium refrigeration control system. Temperature, pressure, and flow parameters are detected by field sensors, and these parameters are collected into the control system for logical operations and displayed and stored in real time on the human-machine interface.

[0008] Preferably, the adsorbent is activated carbon with a specific surface area of ​​1000-2000 m². 2 / g, with a micropore ratio greater than 80%, the activated carbon is bonded to both sides of the adsorption cold plate using low-temperature adhesive, with an effective bonding thickness of 2mm.

[0009] Preferably, the adsorption cold plate refrigeration circuit adopts a turbine expansion refrigeration method, providing 100W of cooling capacity, with the refrigerant temperature at the inlet of the cryogenic pump being less than 6K and the outlet being less than 8K; the umbrella-shaped baffle refrigeration circuit uses a liquid nitrogen storage tank to provide liquid nitrogen, with the pump inlet temperature being less than 80K and the outlet being less than 90K.

[0010] Preferably, the adsorption cold plate and the umbrella-shaped baffle adopt a tube-fin heat exchanger structure, which is welded from branch pipes and fins. The fins are made of oxygen-free copper TU1, the branch pipes are made of thin-walled stainless steel, the fin thickness is 2-3mm, and the maximum temperature difference does not exceed 2K.

[0011] Preferably, the helium refrigeration system includes a helium compressor, a cold box, and auxiliary systems, and adopts a reverse Brayton cycle arrangement. The liquid nitrogen refrigeration system includes a liquid nitrogen storage tank, a liquid nitrogen regulating valve, a safety valve, a sensor, a shut-off valve, and pipeline supports.

[0012] Preferably, the control system is configured as follows: Based on the comparison of collected data with set thresholds, the operating parameters of the liquid nitrogen regulating valve and helium compressor are automatically adjusted, thereby adjusting the temperature of the adsorption cold plate and the baffle.

[0013] A method for obtaining vacuum using an intelligent high-vacuum, ultra-high-speed cryogenic pump includes the following steps: Pre-cooling step: Cool the umbrella-shaped baffle to ≤90K using a liquid nitrogen refrigeration system; Cryogenic step: The adsorption cold plate is cooled to ≤8K using a helium refrigeration system; Pumping procedure: Point the pump inlet of the cryogenic pump toward the vacuum chamber, so that the gas molecules pass through the umbrella-shaped baffle and the adsorption cold plate in sequence, and the gas is adsorbed by activated carbon on the surface of the adsorption cold plate. The precooling and cryogenic steps are performed simultaneously.

[0014] The beneficial effects of this invention are: (1) By setting a baffle in front of the adsorption cold plate, the temperature of the baffle is controlled at ≤90K and the temperature of the adsorption cold plate is controlled at ≤8K, which can effectively prevent radiant heat and 300K gas molecules from directly entering the adsorption cold plate. (2) By alternating adsorption cold plates and umbrella-shaped baffles to form a wheat-ear-shaped cross-section and a symmetrical suspension structure of two pumps in the vacuum chamber, the effective adsorption area is significantly increased compared to the conventional annular single-layer structure, enabling a pumping speed of ≥1×10⁻⁶ hydrogen gas in the vacuum chamber. 6 L / s, the ultimate vacuum level in the vacuum chamber can reach ≤1×10 -5 Pa; (3) This application uses activated carbon with high specific surface area, good pore structure, large equilibrium adsorption capacity, low equilibrium pressure and strong adsorption capacity for small molecules as adsorbent. The number of adsorption saturation is significantly reduced. Under the same gas load, the regeneration cycle of this application is significantly longer than that of traditional cryogenic pumps. The activated carbon only needs to be reactivated after about 4507 injections of supplementary gas. (4) The cooling circuit of the adsorption cold plate uses a turbo expander to provide 100W of cooling capacity, and with the liquid nitrogen shielding shell, the heat load is significantly lower than that of conventional refrigeration machines, and the operating energy consumption is low. (5) The distributed control system has automatic temperature control, fault self-diagnosis, triple safety interlock and data management functions. The system has a short response time to temperature overshoot and a low false alarm rate, which significantly improves the reliability and operational safety of the equipment. (6) The plug-in multi-layer structure of the pump body makes the single pump smaller in size. This cryogenic pump can be installed when the effective volume of the vacuum chamber is greater than 12m³, thus expanding the application scenarios. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the pump body structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a liquid nitrogen refrigeration system according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a helium refrigeration system according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the control system according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the workflow of an embodiment of the present invention.

[0016] Explanation of symbols in the diagram: 1. Liquid nitrogen shielding shell; 2. Adsorption cold plate; 3. Umbrella-shaped baffle; 4. Liquid nitrogen storage tank; 5. Safety valve; 6. Nitrogen control box; 7. Shut-off valve; 8. Liquid nitrogen regulating valve; 9. Return tank; 10. Vaporizer; 11. Vacuum chamber; 12. Helium compressor; 13. Control panel; 14. Helium control box; 15. Cold box and auxiliary system; 16. Inlet flange; 17. Outlet flange; 18. Remote control computer; 19. Local control touch screen; 20. PLC unit; 21. Pump body I; 22. Pump body II; 23. Drain pipe I; 24. Drain pipe II. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments.

[0018] like Figure 1 As shown, this embodiment provides an intelligent high-vacuum ultra-high pumping speed cryogenic pump, including a pump body, a refrigeration system, and a control system. The pump body is equipped with an adsorption array and a liquid nitrogen shielding shell 1. The adsorption unit includes multiple alternately arranged adsorption cold plates 2 and baffles. Adsorbent is applied to the surface of the adsorption cold plates 2. The adsorbent is activated carbon with a specific surface area of ​​1000-2000 m². 2 / g, with a micropore ratio greater than 80%, activated carbon is bonded to both sides of the adsorption cold plate 2 using low-temperature adhesive, with an effective bonding thickness of 2mm.

[0019] The adsorption array consists of multiple adsorption units arranged vertically side by side, with gaps between adjacent units to provide pathways for gas flow. The entire adsorption array is housed within a liquid nitrogen shielded shell 1. The refrigeration system includes a helium refrigeration system and a liquid nitrogen refrigeration system, such as... Figure 5 As shown, the helium refrigeration system provides cooling to the adsorption cold plates 2 in pump body I 21 and pump body II 22 respectively, so that the temperature of the adsorption cold plates 2 is stabilized at ≤8K; the liquid nitrogen refrigeration system provides cooling to the baffle and the liquid nitrogen shield shell 1, so that the temperature of the baffle is stabilized at ≤90K. The helium refrigeration system is equipped with an vent pipe I 23, and the liquid nitrogen refrigeration system is equipped with an vent pipe II 24.

[0020] The control system is a distributed control system with PLC unit 20 as its core. It consists of PLC unit 20, remote control computer 18, local control touch screen 19, and other electrical components. Various field sensors can detect parameters such as temperature, pressure, and flow rate, and these parameters are collected into the control subsystem via data interfaces. These parameters participate in logical operations and are displayed, stored, queried, and printed in real time on the human-machine interface (HMI). It can automatically control the liquid nitrogen and helium processes according to user instructions. A graphical HMI is used to control each subsystem and display its status in real time. The control system also has self-testing, fault diagnosis, and alarm protection programs. It monitors the operating status of each controlled object in real time, detects faults in real time, and promptly identifies faults. Once a fault occurs, it automatically executes protection programs according to the fault level and issues audible and visual alarms. After a fault occurs, relevant fault information, including the fault item, cause, and solution, can be viewed on the HMI. It also features safety protection functions, employing a triple interlocking and interlocking mechanism (interlocking and interlocking protection of hardware circuits, programs, and operating software) to minimize the possibility of misoperation and improve system safety performance. For functions with interlocking and interlocking protection, the system will indicate the reason why operation is not possible; for functions with forced operation, the system will indicate the potential hazards. The system also has data management functions, capable of periodically storing various data generated during operation (temperature, pressure, flow, etc.), and has the functions of historical data query, printing, and generating data reports.

[0021] The pump body adopts an insert-type multi-layer structure and is sealed with the vacuum chamber 11 using a fluororubber sealing ring. There are two pump bodies, left and right, which are respectively suspended on both sides of the vacuum chamber 11 with the pump ports facing each other. Each pump body consists of an adsorption array composed of 8 adsorption units. The adsorption cold plate 2 adopts a three-layer V-shaped plate structure, and the baffle adopts an umbrella-shaped baffle 3. The adsorption cold plate 2 is located behind the umbrella-shaped baffle 3. The adsorption cold plate 2 and the umbrella-shaped baffle 3 are arranged alternately to form a structure with a wheat ear-shaped cross section.

[0022] The control system is responsible for measuring and controlling the parameters of the cryogenic pump, such as... Figure 4 As shown, the control system includes a cryogenic pump body control system, a liquid nitrogen refrigeration control system, and a helium refrigeration control system. The control system is configured to automatically adjust the operating parameters of the liquid nitrogen regulating valve 8 and the helium compressor 12 based on the comparison of collected data with set thresholds, thereby adjusting the temperature of the adsorption cold plate 2 and the umbrella-shaped baffle 3.

[0023] The refrigeration circuit of adsorption cold plate 2 adopts a turbine expansion refrigeration method, providing 100W of cooling capacity. Optimized piping design ensures the refrigerant temperature at the cryogenic pump inlet is less than 6K and the outlet temperature is less than 8K. The refrigeration circuit of umbrella-shaped baffle 3 uses liquid nitrogen storage tank 4 to provide liquid nitrogen. Optimized piping design ensures the pump inlet temperature is less than 80K and the outlet temperature is less than 90K. The heat load of adsorption cold plate 2 is provided by forced convection of helium gas with a cold source of 1.0 bar, an inlet temperature of 6.5K, and a return temperature of 6.85K in the pipeline. Both adsorption cold plate 2 and umbrella-shaped baffle 3 adopt a tube-fin heat exchanger structure, welded from branch pipes and fins. The fins are made of oxygen-free copper TU1, the branch pipes are made of thin-walled stainless steel, the fin thickness is 2-3mm, and the maximum temperature difference does not exceed 2K.

[0024] like Figure 2 As shown, the liquid nitrogen refrigeration system, in addition to the liquid nitrogen storage tank 4 and the liquid nitrogen regulating valve 8, also includes a safety valve 5, a sensor, a shut-off valve 7, a nitrogen control box 6, and pipeline supports. The liquid nitrogen storage tank 4 stores the liquid nitrogen required for cooling and pre-cooling, serving as the cold source storage unit. The liquid nitrogen regulating valve 8 regulates the flow rate of liquid nitrogen entering the liquid nitrogen shield housing 1 or the umbrella-shaped baffle 3, acting as the liquid nitrogen flow rate regulation unit. The safety valve 5 provides overpressure protection for the pipeline, ensuring system safety. The sensor detects the temperature and pressure entering the cryogenic pump or the umbrella-shaped baffle 3. The shut-off valve 7 closes and opens the cryogenic liquid circuit piping components. The pipeline supports secure the pipes and bear their weight. The system delivers liquid nitrogen from the liquid nitrogen storage tank 4 to the umbrella-shaped baffle 3 of the cryogenic pump via a liquid nitrogen delivery pipeline. The liquid nitrogen boils and exchanges heat within the branch pipes of the umbrella-shaped baffle 3, carrying away heat from the fin surface to achieve cooling. To fully utilize the cooling capacity of the liquid nitrogen and achieve medium recycling, the system also includes a vaporizer 10 and a return tank 9. Among them, the vaporizer 10 is used to further reheat and vaporize the gaseous nitrogen or incompletely vaporized liquid nitrogen generated after heat exchange in the system. The vaporized low-temperature nitrogen can be introduced into the pre-cooling channel of the helium refrigeration system to help reduce the initial temperature of the helium and thus reduce the energy consumption of the helium compressor. The return tank 9 is used to collect the incompletely vaporized liquid nitrogen in the system and return the liquid nitrogen to the liquid nitrogen storage tank 4 or re-transport it to the system for use through gravity or pressure difference, so as to realize the recycling of liquid nitrogen, reduce liquid nitrogen loss, and improve the economy and operational stability of the system.

[0025] like Figure 3 As shown, the helium refrigeration system, in addition to the helium compressor 12, also includes a control panel 13, a helium control box 14, a cold box and auxiliary system 15, an inlet flange 16, and an outlet flange 17. It adopts a reverse Brayton cycle arrangement. Helium enters the adsorption cold plate 2 of the cryogenic pump after being cooled and depressurized, providing 100W@7K of cooling capacity to the cryogenic pump.

[0026] This embodiment also provides a method for obtaining vacuum using an intelligent high-vacuum, ultra-high-speed cryogenic pump, including the following steps: Pre-cooling step: Cool the umbrella-shaped baffle 3 to ≤90K using a liquid nitrogen refrigeration system; Cryogenic step: Cool the adsorption cold plate 2 to ≤8K using a helium refrigeration system; Pumping procedure: Point the pump port of the cryogenic pump toward the vacuum chamber 11, so that the gas molecules pass through the umbrella-shaped baffle 3 and the adsorption cold plate 2 in sequence, and the gas is adsorbed by activated carbon on the surface of the adsorption cold plate 3. The precooling and cryogenic steps are performed simultaneously.

[0027] The refrigerant for the three layers of adsorption cold plates and three layers of umbrella-shaped baffles in each adsorption unit is supplied in parallel. At the same time, the adsorption unit and the main liquid supply pipe are also connected in parallel, which greatly reduces the precooling time of the cryogenic pump, reduces operating costs, and improves the reliability of system operation, and divides the adsorption unit into two independent parts.

[0028] This application, by setting an umbrella-shaped baffle 3 in front of the adsorption cold plate 3, with the temperature of the umbrella-shaped baffle 3 controlled at ≤90K and the temperature of the adsorption cold plate 2 controlled at ≤8K, can effectively prevent radiant heat and 300K gas molecules from directly incident on the adsorption cold plate 2. The alternating arrangement of the adsorption cold plate 2 and the umbrella-shaped baffle 3 forms a wheat-ear-shaped cross-section structure, and the two pumps are symmetrically suspended within the vacuum chamber 11. This significantly increases the effective adsorption area compared to a conventional annular single-layer structure, enabling a pumping speed of ≥1×10⁻⁶ hydrogen gas within the vacuum chamber 11. 6 L / s, the ultimate vacuum level inside vacuum chamber 11 can reach ≤1×10 L / s. -5 Pa.

[0029] This application uses activated carbon, which has a high specific surface area, good pore structure, large equilibrium adsorption capacity, low equilibrium pressure, and strong adsorption capacity for small molecules, as the adsorbent. The activated carbon bonding thickness is 2mm, so the total activated carbon loading of a single pump reaches about 4.5-5.0kg, which improves the adsorption capacity and significantly reduces the number of adsorption saturation times. Under the same gas load, the regeneration cycle of this application is significantly longer than that of traditional cryogenic pumps. The activated carbon only needs to be reactivated after about 4507 injections of gas. This achieves the best balance between adsorption capacity, mechanical strength, heat transfer efficiency, and service life. The adsorption cold plate refrigeration circuit uses a turbine expander to provide 100W of cooling capacity, combined with a liquid nitrogen shielding shell 1, resulting in a significantly lower heat load and lower operating energy consumption compared to conventional refrigeration machines. The distributed control system features automatic temperature control, fault self-diagnosis, triple safety interlocks, and data management functions. The system has a short response time to temperature overshoot and a low false alarm rate, significantly improving the reliability and operational safety of the equipment. The plug-in multi-layer pump design makes each pump smaller, allowing the cryogenic pump to be installed in vacuum chambers 11 with an effective volume greater than 12m³, thus expanding its application scenarios.

[0030] This application solves the technical problems of insufficient pumping speed, inadequate vacuum, low level of intelligence, high energy consumption, and large space occupation of cryogenic pumps in the prior art through the above configuration.

[0031] However, the above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A smart high-vacuum ultra-high pumping speed cryogenic pump, characterized in that, The system includes a pump body, a refrigeration system, and a control system. The pump body is equipped with an adsorption array and a liquid nitrogen shielding shell. The adsorption array is composed of multiple adsorption units arranged vertically side by side, with gaps between adjacent adsorption units. Each adsorption unit includes multiple alternating adsorption cold plates and baffles, and the surface of the adsorption cold plates is provided with adsorbent. The refrigeration system includes a helium refrigeration system and a liquid nitrogen refrigeration system; the helium refrigeration system provides cooling for the adsorption cold plate; the liquid nitrogen refrigeration system provides cooling for the baffle and the liquid nitrogen shielding shell; The control system is a distributed control system with PLC as its core. It is configured to monitor the pump body temperature and pressure parameters in real time, automatically adjust the operating status of the refrigeration system according to preset thresholds, and execute fault diagnosis and safety protection programs. The control system adopts a triple interlocking mechanism of hardware circuits, programs and operating software to prevent misoperation.

2. The intelligent high-vacuum ultra-high pumping speed cryogenic pump according to claim 1, characterized in that, The pump body consists of two units, left and right, which are respectively suspended on both sides of the vacuum chamber with their pump ports facing each other. Each pump body includes an adsorption array consisting of 8 adsorption units. The adsorption cold plate adopts a three-layer V-shaped plate structure, and the baffle adopts an umbrella-shaped baffle. The adsorption cold plate is located behind the umbrella-shaped baffle. The adsorption cold plate and the umbrella-shaped baffle are arranged alternately to form a structure with a wheat ear-shaped cross section.

3. The intelligent high-vacuum ultra-high pumping speed cryogenic pump according to claim 1, characterized in that, The pump body adopts an insert-type multi-layer structure and is sealed to the vacuum chamber with a fluororubber sealing ring.

4. The intelligent high-vacuum ultra-high pumping speed cryogenic pump according to claim 1, characterized in that, The control system includes a cryogenic pump body control system, a liquid nitrogen refrigeration control system, and a helium refrigeration control system. Temperature, pressure, and flow parameters are detected by field sensors, and these parameters are collected into the control system for logical operations and displayed and stored in real time on the human-machine interface.

5. The intelligent high-vacuum ultra-high pumping speed cryogenic pump according to claim 1, characterized in that, The adsorbent is activated carbon with a specific surface area of ​​1000–2000 m². 2 / g, with a micropore ratio greater than 80%, the activated carbon is bonded to both sides of the adsorption cold plate using low-temperature adhesive, with an effective bonding thickness of 2mm.

6. The intelligent high-vacuum ultra-high pumping speed cryogenic pump according to claim 2, characterized in that, The refrigeration circuit of the adsorption cold plate adopts a turbine expansion refrigeration method, providing a cooling capacity of 100W. The inlet refrigerant temperature of the cryogenic pump is less than 6K and the outlet temperature is less than 8K. The refrigeration circuit of the umbrella-shaped baffle adopts a liquid nitrogen storage tank to provide liquid nitrogen. The inlet temperature of the pump is less than 80K and the outlet temperature is less than 90K.

7. The intelligent high-vacuum ultra-high pumping speed cryogenic pump according to claim 2, characterized in that, The adsorption cold plate and umbrella-shaped baffle adopt a tube-fin heat exchanger structure, which is welded from branch pipes and fins. The fins are made of oxygen-free copper TU1, the branch pipes are made of thin-walled stainless steel, the fin thickness is 2-3mm, and the maximum temperature difference does not exceed 2K.

8. The intelligent high-vacuum ultra-high pumping speed cryogenic pump according to claim 1, characterized in that, The helium refrigeration system includes a helium compressor, a cold box, and auxiliary systems, and adopts a reverse Brayton cycle arrangement. The liquid nitrogen refrigeration system includes a liquid nitrogen storage tank, a liquid nitrogen regulating valve, a safety valve, a sensor, a shut-off valve, and pipeline supports.

9. The intelligent high-vacuum ultra-high pumping speed cryogenic pump according to claim 8, characterized in that, The control system is configured to automatically adjust the operating parameters of the liquid nitrogen regulating valve and the helium compressor based on the comparison of the collected data with the set threshold, thereby adjusting the temperature of the adsorption cold plate and the baffle.

10. A method for obtaining vacuum using the intelligent high-vacuum ultra-high pumping speed cryogenic pump described in claims 1-9, characterized in that, Includes the following steps: Pre-cooling step: Cool the umbrella-shaped baffle to ≤90K using a liquid nitrogen refrigeration system; Cryogenic step: The adsorption cold plate is cooled to ≤8K using a helium refrigeration system; Pumping procedure: Point the pump inlet of the cryogenic pump toward the vacuum chamber, so that the gas molecules pass through the umbrella-shaped baffle and the adsorption cold plate in sequence, and the gas is adsorbed by activated carbon on the surface of the adsorption cold plate. The precooling and cryogenic steps are performed simultaneously.

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