A low-temperature vacuum pump convenient to disassemble and replace

Abstract

This invention discloses a cryogenic vacuum pump that is easy to disassemble and replace. The cold shield, adsorption array, and baffle are fixedly connected into a rigid, integrated structure. Only the adsorption array is detachably fixed to the secondary cold head of the refrigerator. During maintenance, the entire pump can be removed and reassembled simultaneously without disassembling the connection structure between the cold shield, adsorption array, and baffle. This reduces the difficulty and time required for disassembly and installation during maintenance. When the adsorption array is fixedly installed on the secondary cold head of the refrigerator, the cold shield fits precisely against the primary cold head. The adsorption array is cooled by the secondary cold head to maintain an ultra-low temperature, while the cold shield is cooled by the primary cold head to maintain a low temperature. A thermal insulator connection isolates the cold shield from temperature transfer between the two, maintaining the temperature difference between them. A thermally conductive connection ensures that the temperature of the baffle and the cold shield remains consistent, guaranteeing the normal operation of the cryogenic vacuum pump.

Description

Technical Field

[0001] This invention belongs to the field of vacuum equipment technology and relates to a cryogenic vacuum pump, specifically a cryogenic vacuum pump that is easy to disassemble and replace. Background Technology

[0002] Cryogenic vacuum pumps achieve high vacuum by trapping gas molecules through cryogenic condensation and adsorption. For example... Figure 1 As shown, the cryogenic vacuum pump mainly consists of a vacuum housing, a refrigerator, a cold shield, a baffle, and an adsorption array. The vacuum housing is sealed to the cavity to be evacuated. The cold shield is located inside the vacuum housing and is fixedly connected to the first-stage cold head of the refrigerator. The adsorption array is located inside the cold shield and is fixedly connected to the second-stage cold head of the refrigerator. The baffle is fixedly installed inside the inlet of the cold shield. During normal operation, the baffle and cold shield are cooled by the first-stage cold head of the refrigerator, with an operating temperature of 60-100K. The adsorption array is cooled by the second-stage cold head of the refrigerator, with an operating temperature of 8-20K. As gas molecules enter the cryogenic vacuum pump from the cavity to be evacuated, they are successively condensed and adsorbed by the temperature gradients on the baffle, cold shield, and adsorption array, achieving an oil-free and clean evacuation process.

[0003] Due to varying operating temperatures, traditional cryogenic vacuum pumps have direct contact between the cold shield and the baffle to avoid thermal contact between components operating at different temperatures, while there is no physical contact between the cold shield / baffle and the adsorption array. During installation, the cold shield must first be installed on the first cold head of the chiller, then the adsorption array is placed inside the cold shield and installed on the second cold head of the chiller, and finally the baffle is installed on top of the cold shield. During maintenance, the baffle must be removed from the cold shield, the adsorption array must be removed from the second cold head of the chiller and taken out from inside the cold shield, and finally the cold shield must be removed from the first cold head of the chiller. This cumbersome disassembly and assembly process necessitates improvement in the convenience of maintenance and repair. Summary of the Invention

[0004] To address the technical problems existing in the background art, this invention proposes a low-temperature vacuum pump that is easy to disassemble and replace. The cold shield, adsorption array and baffle are set into an integrated structure, realizing overall disassembly and maintenance, and improving the convenience of repair and maintenance.

[0005] The objective of this invention can be achieved through the following technical solutions: A low-temperature vacuum pump that is easy to disassemble and replace includes: a vacuum housing, a refrigerator, a cold shield, an adsorption array, and a baffle. One end of the vacuum housing is provided with a pump port for sealing and connecting to the cavity to be evacuated. The refrigerator is sealed and connected to the other end of the vacuum housing. The cold shield is set inside the vacuum housing. The adsorption array and the baffle are both fixedly connected inside the cold shield to form an integrated structure. The adsorption array and the cold shield are thermally insulated and thermally conductive. When the adsorption array is fixedly installed on the second-stage cold head of the refrigerator, the cold shield is pressed tightly against the first-stage cold head of the refrigerator.

[0006] Furthermore, an end plate is provided at the end of the cold shield near the refrigerator. The first-stage cold head of the refrigerator extends into the vacuum housing and abuts against the end plate of the cold shield. The second-stage cold head of the refrigerator passes through the end plate and is fixedly connected to the adsorption array inside the cold shield.

[0007] Furthermore, the adsorption array is fixedly installed on the end plate of the cold screen by a heat insulation support assembly. The heat insulation support assembly rigidly connects the cold screen and the adsorption array and can isolate the heat conduction between the cold screen and the adsorption array.

[0008] Furthermore, the thermal insulation support assembly uses materials with a thermal conductivity of no more than [value missing]. Made of a rigid material with low thermal conductivity, it relies on its own low thermal conductivity to isolate the heat conduction across the temperature range between the cold screen and the adsorption array.

[0009] Furthermore, the thermal insulation support assembly includes one or more sets of height-adjustable telescopic structures to adjust the physical gap between the end plate of the cold shield and the adsorption array, so that the end plate of the cold shield precisely fits the first-stage cold head of the refrigeration unit.

[0010] Furthermore, an air inlet is provided at the end of the cold screen away from the refrigerator. The baffle is fixedly installed inside the air inlet of the cold screen to shield the adsorption array from direct thermal radiation from external gas molecules. The cold screen is connected to the baffle through a heat-conducting rod to synchronously transfer the cooling capacity of the first-stage cold head of the refrigerator to the baffle.

[0011] Furthermore, the baffle adopts multiple coaxially arranged annular baffles, which are inclined to form a tortuous channel for gas molecules to pass through between any two adjacent annular baffles.

[0012] Furthermore, one or more heat-conducting rods are provided, which pass radially through the center of multiple annular baffles to connect and fix the multiple annular baffles.

[0013] Furthermore, the adsorption array and the secondary cold head of the refrigerator are detachably connected by fasteners. The baffle plate has operation through holes corresponding to the fasteners, which are used for disassembly tools to directly tighten or loosen the fasteners between the adsorption array and the secondary cold head of the refrigerator by passing through the baffle plate.

[0014] The beneficial effects of this invention are as follows: The cryogenic vacuum pump provided in this application integrates the cold screen, adsorption array, and baffle into a rigid whole structure. The adsorption array is detachably fixed to the secondary cold head of the refrigerator. During maintenance, the entire unit can be simultaneously removed and reassembled without the need to separately disassemble the connection structure between the cold screen, adsorption array, and baffle. This reduces the difficulty of disassembly and installation during maintenance and shortens maintenance time. When the adsorption array is fixedly installed on the secondary cold head of the refrigerator, the cold screen fits precisely against the primary cold head. The adsorption array is cooled by the secondary cold head to maintain ultra-low temperatures, while the cold screen is cooled by the primary cold head to maintain low temperatures. A thermal insulator connection isolates the temperature transfer between the cold screen and the adsorption array, maintaining the temperature difference between them. A thermally conductive connection ensures that the temperature of the baffle and the cold screen remains consistent, guaranteeing the normal operation of the cryogenic vacuum pump. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a cryogenic vacuum pump in the prior art.

[0016] Figure 2 This is a three-dimensional schematic diagram of the cryogenic vacuum pump of the present invention.

[0017] Figure 3 This is a cross-sectional schematic diagram of the cryogenic vacuum pump of the present invention.

[0018] Figure 4 This is a three-dimensional schematic diagram of the cold screen of the present invention.

[0019] Figure 5 This is a three-dimensional schematic diagram of the adsorption array and baffle of the present invention.

[0020] Figure 6 This is a schematic diagram of the integrated structure of the cold screen, adsorption array, and baffle of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figure 2As shown, this invention provides a cryogenic vacuum pump that is easy to disassemble and replace, comprising: a vacuum housing 1, a refrigerator 2, a cold shield 3, an adsorption array 4, and a baffle 5. One end of the vacuum housing 1 is provided with a pump port 6 for sealing and connecting to a cavity to be evacuated, through which gas molecules in the cavity to be evacuated enter the vacuum housing 1. The other end of the vacuum housing 1 is provided with a flange for mounting the refrigerator 2, which is sealed to the vacuum housing 1 via the flange. Both the primary and secondary cold heads of the refrigerator 2 extend into the vacuum housing 1 from the flange opening.

[0023] Both the vacuum housing 1 and the cold shield 3 are cylindrical, with the cold shield 3 coaxially arranged inside the vacuum housing 1. Figure 3 As shown, the adsorption array 4 and the baffle 5 are coaxially arranged inside the cold screen 3 and fixedly connected to the cold screen 3, forming a rigid whole structure. During maintenance, they can be removed and reassembled simultaneously without disassembling the connection structure between the cold screen 3, the adsorption array 4, and the baffle 5. This reduces the difficulty of disassembly and installation during maintenance and shortens the maintenance time.

[0024] The refrigerator 2 employs a two-stage Gifford-McMahon GM refrigerator or a pulse tube refrigerator. The adsorption array 4 is fixedly mounted on the second-stage cold head of the refrigerator 2, maintaining its surface temperature at an ultra-low temperature. Since the cold screen 3, adsorption array 4, and baffle 5 are integrated, when the adsorption array 4 is fixedly mounted on the second-stage cold head of the refrigerator 2, the cold screen 3 fits precisely against the first-stage cold head of the refrigerator 2, thus maintaining its surface temperature at a low temperature. The cold screen 3 and baffle 5 are thermally connected, ensuring that the surface temperature of the baffle 5 remains at the same low temperature as the cold screen 3. When gas molecules entering the vacuum chamber 1 encounter the cold screen 3, adsorption array 4, and baffle 5, whose temperatures are far below their saturated vapor pressure, the gas molecules lose kinetic energy and directly transform from a gaseous phase to a solid phase (sublimation), condensing into a layer of frost. This reduces the density of gas molecules in the vacuum chamber, achieving and maintaining a high vacuum or even an ultra-high vacuum.

[0025] The cold screen 3 and the adsorption array 4 are thermally insulated, which isolates the temperature transfer between them and maintains a surface temperature difference. The surface temperature of the cold screen 3 and the baffle 5 is maintained at a low temperature of 60K-100K, while the surface temperature of the adsorption array 4 is maintained at an ultra-low temperature of 8K-20K. The vacuum shell 1, in direct contact with the external environment, maintains a surface temperature of 300K, thus forming a sleeve-like structure with a gradually decreasing temperature from the outside in. The cold screen 3 and the baffle 5 shield the vacuum shell 1 from heat radiation, ensuring the ultra-low temperature operating environment of the innermost adsorption array 4 and significantly reducing the heat load on the refrigerator 2. Simultaneously, the low temperature of 60K-100K on the surfaces of the cold screen 3 and the baffle 5 is sufficient to condense and capture the main gaseous components such as water vapor (H2O) and carbon dioxide (CO2), which have higher saturated vapor pressures, completing the initial condensation and capture of gas molecules. The adsorption array 4 consists of multiple layers of spaced condenser plates. It can condense and capture gases with relatively low saturated vapor pressures, such as nitrogen (N2), oxygen (O2), and argon (Ar), at ultra-low temperatures of 8K-20K. However, for gases that still have high saturated vapor pressures at extremely low temperatures, condensation alone is insufficient for effective capture. Therefore, activated carbon with a large specific surface area is bonded to the surface of the condenser plates. At ultra-low temperatures of 8K-20K, gas molecules are firmly bound to the surface of the activated carbon micropores through physical adsorption, thus capturing difficult-to-condense gas molecules such as hydrogen (H2), helium (He), and neon (Ne) through low-temperature adsorption.

[0026] Specifically, such as Figures 4-6 As shown, the end plate 31 of the cold shield 3 near the refrigerator 2 is provided. The first-stage cold head of the refrigerator 2 extends into the vacuum housing 1 and abuts against the end plate 31 of the cold shield 3. The second-stage cold head of the refrigerator 2 passes through the end plate 31 and is fixedly connected to the adsorption array 4 inside the cold shield 3. The adsorption array 4 is fixedly installed on the end plate 31 of the cold shield 3 by a heat insulation support assembly 7. The heat insulation support assembly 7 rigidly connects the cold shield 3 and the adsorption array 4 and can isolate the heat conduction between the cold shield 3 and the adsorption array 4. The heat insulation support assembly 7 uses materials with a thermal conductivity of no more than [value missing]. It is made of a low thermal conductivity rigid material, which relies on its low thermal conductivity to isolate the heat conduction across the temperature range between the cold screen 3 and the adsorption array 4. In this embodiment, the low thermal conductivity rigid material can be selected from polyimide or fiberglass epoxy board.

[0027] The heat insulation support assembly 7 includes multiple sets of height-adjustable telescopic structures to adjust the physical gap between the end plate 31 of the cold shield 3 and the adsorption array 4. This ensures that when the adsorption array 4 is fixedly installed onto the secondary cold head of the refrigerator 2, the end plate 31 of the cold shield 3 can precisely fit against the primary cold head of the refrigerator 2, preventing over-positioning or poor contact between the cold shield 3 and the primary cold head of the refrigerator 2, and guaranteeing efficient heat conduction contact between the primary cold head of the refrigerator 2 and the cold shield 3. The multiple sets of height-adjustable telescopic structures are evenly arranged circumferentially along the adsorption array 4, collaboratively bearing the weight of the adsorption array 4, resulting in uniform overall stress and ensuring a uniform, full-plane fit between the cold shield 3 and the primary cold head of the refrigerator 2 after assembly. In this embodiment, the height-adjustable telescopic structure employs a combination of hydraulic rods and hydraulic cylinders with precisely adjustable pressure. The height is changed by preset internal pressure, precisely controlling the separation distance between the adsorption array 4 and the cold shield 3.

[0028] An air inlet 32 ​​is provided at the end of the cold screen 3 furthest from the refrigerator 2, allowing gas molecules from the vacuum housing 1 to enter the cold screen 2 through the air inlet 32. A baffle 5 is fixedly installed inside the air inlet 32 ​​of the cold screen 3 and rigidly connected to the inner wall of the cold screen 3 via a heat-conducting rod 8. The heat-conducting rod 8 is made of a high thermal conductivity material. Utilizing the heat conduction effect of the heat-conducting rod 8, the cooling capacity of the first-stage cold head of the refrigerator 2 is synchronously transferred from the cold screen 3 to the baffle 5, maintaining the baffle 5 at a low temperature of 60K-100K synchronized with the cold screen 3, thus shielding the adsorption array 4 from direct thermal radiation from external gas molecules at the air inlet 32. Specifically, the baffle 5 employs multiple coaxially arranged annular baffles, which are inclined to form a tortuous channel for gas molecules to pass through between any two adjacent annular baffles. This prevents gas molecules from directly radiating the coldest adsorption array 4 surface along a straight path, allowing them to enter only through multiple reflections. With each reflection, the gas molecules transfer some heat to the baffle 5, thus significantly reducing the direct impact of high-temperature gas molecules and thermal radiation on the ultra-low temperature adsorption array 4. In this embodiment, two heat-conducting rods 8 are provided, intersecting perpendicularly and passing radially through the center of the multiple annular baffles to connect and fix them.

[0029] The adsorption array 4 and the secondary cold head of the refrigerator 2 are detachably connected by fasteners such as screws. After the adsorption array 4 is assembled, the pre-tightening force generated by the fasteners can be transmitted to the cold screen 3 through the heat insulation support component 7, so that the cold screen 3 presses tightly against the primary cold head of the refrigerator 2. In this embodiment, six sets of fasteners are provided, which are correspondingly set at the bottom of the adsorption array 4. The integrated structure of the cold screen 3, adsorption array 4 and baffle 5 can be removed by simply removing and installing the six sets of fasteners. Since the baffle 5 is set inside the air inlet 32 ​​of the cold screen 3, it will block the operation path of the fasteners on the adsorption array 4. Therefore, six operation through holes corresponding to the six sets of fasteners are opened on the baffle 5, which can be used for disassembly tools to directly tighten and loosen the fasteners between the adsorption array 4 and the secondary cold head of the refrigerator 2 through the baffle 5.

[0030] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A cryogenic vacuum pump that is easy to disassemble and replace, characterized in that, include: Vacuum housing (1), refrigerator (2), cold screen (3), adsorption array (4), baffle (5). One end of the vacuum housing (1) is provided with a pump port (6) for sealing and connecting the cavity to be evacuated. The refrigerator (2) is sealed and connected to the other end of the vacuum housing (1). The cold screen (3) is set inside the vacuum housing (1). The adsorption array (4) and the baffle (5) are both fixedly connected inside the cold screen (3) to form an integrated structure. The adsorption array (4) and the cold screen (3) are thermally insulated and connected to each other. The baffle (5) and the cold screen (3) are thermally conductive. When the adsorption array (4) is fixedly installed on the secondary cold head of the refrigerator (2), the cold screen (3) presses tightly against the primary cold head of the refrigerator (2).

2. The cryogenic vacuum pump according to claim 1, characterized in that, The end plate (31) of the cold screen (3) near the refrigerator (2) is provided. The first-stage cold head of the refrigerator (2) extends into the vacuum housing (1) and abuts against the end plate (31) of the cold screen (3). The second-stage cold head of the refrigerator (2) passes through the end plate (31) and is fixedly connected to the adsorption array (4) inside the cold screen (3).

3. The cryogenic vacuum pump according to claim 2, characterized in that, The adsorption array (4) is fixedly installed on the end plate (31) of the cold screen (3) by the heat insulation support assembly (7). The heat insulation support assembly (7) rigidly connects the cold screen (3) and the adsorption array (4) and can isolate the heat conduction between the cold screen (3) and the adsorption array (4).

4. The cryogenic vacuum pump according to claim 3, characterized in that, The thermal insulation support component (7) is made of a low thermal conductivity rigid material with a thermal conductivity of no more than 0.5 W / (m・K), and relies on its own low thermal conductivity to isolate the cross-temperature heat conduction between the cold screen (3) and the adsorption array (4).

5. The cryogenic vacuum pump according to claim 3, characterized in that, The thermal insulation support assembly (7) includes one or more sets of height-adjustable telescopic structures to adjust the physical gap between the end plate (31) of the cold screen (3) and the adsorption array (4), so that the end plate (31) of the cold screen (3) is precisely fitted to the first-stage cold head of the refrigeration unit (2).

6. The cryogenic vacuum pump according to claim 2, characterized in that, The end of the cold screen (3) away from the refrigerator (2) is provided with an air inlet (32). The baffle (5) is fixedly installed in the air inlet (32) of the cold screen (3) to shield the direct thermal radiation of external gas molecules to the adsorption array (4). The cold screen (3) is connected to the baffle (5) through the heat-conducting rod (8) to synchronously transfer the cooling capacity of the first-stage cold head of the refrigerator (2) to the baffle (5).

7. The cryogenic vacuum pump according to claim 6, characterized in that, The baffle (5) adopts a multi-ring coaxially arranged annular baffle, which is inclined to form a tortuous channel for gas molecules to pass through between any two adjacent annular baffles.

8. The cryogenic vacuum pump according to claim 7, characterized in that, One or more heat-conducting rods (8) are provided, and the heat-conducting rods (8) pass through the center of the multiple ring baffles radially to connect and fix the multiple ring baffles.

9. The cryogenic vacuum pump according to claim 6, characterized in that, The adsorption array (4) and the secondary cold head of the refrigerator (2) are detachably connected by fasteners. The baffle (5) has operation through holes corresponding to the fasteners, so that the disassembly and assembly tools can pass through the baffle (5) to directly tighten or disassemble the fasteners between the adsorption array (4) and the secondary cold head of the refrigerator (2).

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