High sealing large-diameter low-temperature vacuum pump

Abstract

The application accords with the technical field of vacuum pumps, and mainly relates to a high-sealing large-diameter low-temperature vacuum pump. The pump shell is provided with a top cover, an exhaust port, a gas inlet communicated with the pump shell, a first-stage cold head and a plurality of radiation baffles arranged on the upper side in the pump shell, a second-stage cold head and a condensation array, and a fixed plate fixedly connected to the pump shell and provided with heat-absorbing rings equally spaced and located outside the condensation array. The heat-absorbing rings arranged outside the condensation array replace the radiation baffles close to the inner wall of the pump shell, the space between the condensation array and the inner wall of the pump shell is fully utilized, the space utilization in the pump shell is improved, the surface area of the equally spaced heat-absorbing rings is larger than that of the radiation baffles close to the inner wall of the pump shell, the amount of captured gas is increased, and the heat radiation from the inner wall of the pump shell is effectively shielded.

Description

Technical Field

[0001] This invention relates to the field of vacuum pump technology, and in particular to a high-sealing, large-diameter cryogenic vacuum pump. Background Technology

[0002] A cryogenic vacuum pump is a device that uses cryogenic condensation and adsorption to capture gas molecules to achieve a high vacuum environment. High-sealing, large-diameter cryogenic vacuum pumps, due to their unique ability to handle large gas volumes, are widely used in semiconductor manufacturing, aerospace simulation, high-energy physics research, and other fields. Their core structure includes a pump casing, a primary cold head with external radiation baffles, a secondary cold head with external condensation arrays, and a cryogenic condensation array cooled to extremely low temperatures (typically below 20K) by a refrigerant (such as liquid nitrogen, liquid helium, or a GM refrigerator), thereby condensing and capturing gas molecules. In existing technologies, cryogenic vacuum pumps typically employ radiation baffles (or radiation shields) installed inside the pump casing inlet and internal space to block external thermal radiation from entering the cryogenic region of the pump casing, while simultaneously intercepting gas molecules to improve condensation efficiency. A common arrangement of radiation baffles is a dense array on the upper part of the pump casing inner wall (i.e., along the gas entry path), aiming to completely cover the cross-section of the upper side of the pump casing inner wall. This layout effectively blocks thermal radiation and condenses and captures large amounts of high-boiling-point gases (such as water vapor, hydrocarbon oil vapor, etc.).

[0003] This arrangement has obvious limitations. Since the radiation baffles are only concentrated near the pump inlet and in a local area of ​​the inner wall, the annular or edge area between the condenser array and the inner wall of the pump casing is not fully utilized, forming a "structural dead zone". This area not only cannot participate in the effective gas condensation process, but also becomes an indirect conduction path for heat radiation and a reflection escape channel for gas molecules. As a result, the thermal shielding efficiency is low, the uncovered inner wall area of ​​the pump casing continues to radiate heat to the condenser array, the secondary cold head and the condenser array have a large heat load, resulting in wasted cooling power and decreased system stability. Some gas near the inner wall of the pump casing fails to contact the secondary cold head and the condenser array in a short time after passing through the radiation baffle, thereby reducing the effective pumping speed and ultimate vacuum. The internal space of the large-diameter pump body is not fully optimized, and the condensation area per unit volume is limited, which restricts the pumping capacity of the cryogenic pump. Summary of the Invention

[0004] To overcome the shortcomings of existing cryogenic vacuum pumps, which have low pumping capacity due to the underutilization of some space, this invention provides a high-space-utilization, high-sealing, large-diameter cryogenic vacuum pump.

[0005] The technical solution is as follows: A high-sealing, large-diameter cryogenic vacuum pump includes a pump casing, a top cover mounted on the upper side of the pump casing, an exhaust port on the lower side of the pump casing, an air inlet communicating with the pump casing on the top cover, a primary cold head and several radiant baffles with gradually increasing radiant radiants mounted on the upper side inside the pump casing, adjacent radiant baffles, the innermost radiant baffle and the primary cold head being connected to the outermost radiant baffle and the pump casing via connectors, a secondary cold head and a condenser array mounted on the lower side of the pump casing, a fixing plate fixed to the pump casing, and heat-absorbing rings evenly spaced vertically and located outside the condenser array on the fixing plate, the heat-absorbing rings being made of the same material as the radiant baffles, a primary refrigeration module for cooling the primary cold head, the radiant baffles and the heat-absorbing rings, and a secondary refrigeration module for cooling the secondary cold head and the condenser array.

[0006] Furthermore, the distance between the radiating baffle and the condensation array is equal to the width of the gap between the heat-absorbing ring and the condensation array.

[0007] Furthermore, there is a gap between the outermost radiation baffle and the inner wall of the pump casing.

[0008] Furthermore, the vertical cross-section of the heat-absorbing ring is a V-shape with the opening facing downwards.

[0009] Furthermore, a guide ring is fixed to the outer side of the heat-absorbing ring to guide the gas between the two corresponding heat-absorbing rings.

[0010] Furthermore, the height of the outer ring of the guide ring is higher than the height of its inner ring.

[0011] Furthermore, the outer diameter of the equally spaced guide rings gradually increases from top to bottom.

[0012] Furthermore, a rotating ring is rotatably connected inside the pump casing, and the pump casing is provided with a power module for driving the rotating ring to rotate. The rotating ring is fixed with symmetrically distributed arc-shaped plates, and the arc-shaped plates are provided with equally spaced sliding grooves. The heat-absorbing ring is fixed with symmetrically distributed connecting rods on the side near the condensation array, and the connecting rods slide in adjacent sliding grooves. The sliding grooves are inclined grooves, and the equally spaced heat-absorbing rings are all slidably connected to the fixed plate.

[0013] Furthermore, the inclination angle of the equally spaced grooves on the same curved plate gradually increases from top to bottom.

[0014] Furthermore, the outer diameter of the bottommost guide ring is equal to the inner diameter of the pump casing, and the pump casing is provided with an annular groove, which is located above the bottommost guide ring.

[0015] The beneficial effects are as follows: This invention replaces the radiant baffle near the inner wall of the pump casing with heat-absorbing rings installed on the outside of the condenser array, making full use of the space between the condenser array and the inner wall of the pump casing, thus improving the space utilization rate inside the pump casing. Furthermore, the surface area of ​​the evenly spaced heat-absorbing rings is larger than that of the radiant baffle near the inner wall of the pump casing, increasing the amount of gas captured and effectively shielding against heat radiation from the inner wall of the pump casing. The width of the gap between the heat-absorbing rings and the condenser array is equal to the distance between the radiant baffle and the condenser array, ensuring high pumping speed for gas molecules, thereby achieving large-diameter air intake. Through the guiding effect of the flow-guiding rings, the gas molecules inside the pump casing near the inner wall... The gas molecules on its inner wall are uniformly guided to the equally spaced heat-absorbing rings, ensuring a uniform distribution of gas molecules and thus improving the heat-absorbing rings' capture efficiency of gas molecules. By changing the spacing between adjacent heat-absorbing rings, the number of times thermal radiation bounces between adjacent heat-absorbing rings is increased, thereby increasing the shielding amount of thermal radiation. This compensates for the impact of the reduced thermal radiation shielding area of ​​the heat-absorbing rings due to the shielding of the solid layer. Furthermore, the reduced spacing between adjacent heat-absorbing rings decreases the distance between gas molecules and the surface of the heat-absorbing rings, thereby increasing the amount of gas molecules captured by the unshielded parts of the heat-absorbing rings. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0017] Figure 2 This is a three-dimensional structural cross-sectional view of the present invention;

[0018] Figure 3 This is a three-dimensional structural diagram of the arc-shaped plate and connecting rod of the present invention;

[0019] Figure 4 This is a three-dimensional structural diagram of the slide and connecting rod of the present invention.

[0020] Component names and serial numbers in the diagram: 1-Pump housing, 101-Exhaust port, 102-Annular groove, 2-Top cover, 201-Air inlet, 301-First-stage cold head, 302-Radiant baffle, 303-Connector, 401-Second-stage cold head, 402-Condensation array, 5-Fixing plate, 6-Heat absorption ring, 7-Guide ring, 8-Rotating ring, 9-Curved plate, 901-Slide groove, 10-Connecting rod. Detailed Implementation

[0021] The preferred technical solution of the present invention will be described in detail below with reference to the accompanying drawings. Example 1

[0022] The existing cryogenic vacuum pump has its internal radiation baffles arranged in such a way that the upper cross-section of the inner wall of the pump casing is completely filled to intercept the gas entering the pump casing. Although this arrangement can effectively block the heat radiation entering the pump casing and capture most of the water vapor and high-boiling-point gases (such as hydrocarbon oil vapor), the area between the condensation array and the inner wall of the pump casing is not utilized. This results in a low amount of heat radiation shielded by the cryogenic vacuum pump and a low amount of gas absorption, thus affecting the efficiency of the cryogenic vacuum pump in handling gases.

[0023] A high-sealing, large-diameter cryogenic vacuum pump, such as Figures 1-3As shown, the system includes a pump housing, a top cover 2 mounted on the upper side of the pump housing 1, an exhaust port 101 on the lower side of the pump housing 1, a back pump (not shown) connected to the exhaust port 101 for extracting gas from the pump housing 1, a vacuum system (not shown) for achieving a vacuum environment inside the pump housing 1, an air inlet 201 connected to the top cover 2, a primary cold head 301 on the upper side inside the pump housing 1, and several radiation baffles 302 with gradually increasing radii located outside the primary cold head 301 inside the pump housing 1. A gap exists between the outermost radiation baffle 302 and the inner wall of the pump housing 1, allowing some gas molecules entering the pump housing 1 to move downwards along the gap between the outermost radiation baffle 302 and the inner wall of the pump housing 1. Each radiant baffle 302, the innermost radiant baffle 302, and the first-stage cold head 301 are connected to the outermost radiant baffle 302 and the pump housing 1 via connectors 303 (the purpose of connectors 303 is only to fix the above-mentioned parts). The pump housing 1 is provided with a first-stage refrigeration module for cooling the first-stage cold head 301 and the radiant baffle 302. The operating temperature range of the first-stage cold head 301 and the radiant baffle 302 is 50K-80K. A second-stage cold head 401 is provided on the lower side of the pump housing 1. The second-stage cold head 401 is provided with a condenser array 402 located below the first-stage cold head 301. The pump housing 1 is provided with a second-stage refrigeration module for cooling the second-stage cold head 401 and the condenser array 402. The operating temperature range of the second-stage cold head 401 and the condenser array 402 is 10K. -20K. Both the primary and secondary refrigeration modules are cryogenic refrigerators mounted on the pump housing 1. The refrigeration principle of the cryogenic refrigerator is GM cycle. The condenser array 402 is generally covered with a layer of adsorbent with a very high surface area to adsorb hydrogen and helium, which are difficult to condense. The pump housing 1 is fixed with two symmetrically distributed fixed plates 5. The fixed plates 5 are provided with heat-absorbing rings 6 distributed at equal intervals (in this embodiment, the heat-absorbing rings 6 are considered to be fixed to the fixed plates 5). The heat-absorbing rings 6 are all located on the outside of the condenser array 402, effectively shielding the heat radiation from the inner wall of the pump housing 1. The material of the heat-absorbing rings 6 is the same as that of the radiation baffles 302. The heat-absorbing rings 6 are equivalent to radiation baffles 302 in different positions and distributions. The principle of gas molecule capture by the heat-absorbing ring 6 is the same as that of the radiation baffle 302. The distance between the radiation baffle 302 and the condensation array 402 is equal to the width of the gap between the heat-absorbing ring 6 and the condensation array 402, ensuring a high pumping speed for gas molecules (if the existing installation method of the radiation baffle 302 is used, gas molecules passing through the radiation baffle 302 near the inner wall of the pump casing 1 are less likely to contact the condensation array 402 compared to gas molecules moving downwards in the middle, thus reducing the pumping speed). The vertical cross-section of the heat-absorbing ring 6 is a V-shape with an opening facing downwards, which makes the heat radiation from the pump casing 1 reflected between adjacent heat-absorbing rings 6, thereby increasing the amount of shielded heat radiation. A flow-guiding ring 7 is fixed to the outer side of the heat-absorbing ring 6, and the height of the outer ring surface of the flow-guiding ring 7 is higher than the height of its inner ring surface.The outer diameter of the equally spaced guide rings 7 gradually increases from top to bottom, which uniformly guides gas molecules near the inner wall of the pump casing 1 to the spaced heat-absorbing rings 6, ensuring a uniform distribution of gas molecules and thus improving the gas molecule capture efficiency of the heat-absorbing rings 6. The primary refrigeration module is used to cool the equally spaced heat-absorbing rings 6.

[0024] Initially, both the exhaust port 101 and the inlet port 201 are closed, creating a sealed environment inside the pump housing 1. When this cryogenic vacuum pump is needed to condense and capture gas molecules, the operator first evacuates the pump housing 1 using the vacuum system. Once a vacuum environment is achieved, the operator activates the primary cooling module to cool the primary cold head 301, all radiant baffles 302, and all heat-absorbing rings 6, maintaining their temperatures between 50K and 80K. Simultaneously, the secondary cooling module is activated to cool the secondary cold head 401 and the condenser array 402, maintaining their temperatures between 10K and 20K. This temperature reduction within the pump housing 1 maintains a stable operating temperature. In a vacuum state, when the aforementioned components reach the required temperature, the operator opens the air inlet 201, and the gas to be extracted is drawn into the pump housing 1 through the air inlet 201. The gas molecules near the middle of the pump housing 1 first come into contact with the primary cold head 301 and the radiation baffle 302. The primary cold head 301 and the radiation baffle 302 capture water vapor and some high-boiling-point gases, causing these gas molecules to instantly lose kinetic energy and condense directly into a solid state. At the same time, the radiation baffle 302 shields most of the heat radiation from above the pump housing 1 and the gas entering the pump housing 1, thereby protecting the secondary cold head 401 and the condensation array 402 below it. The gas molecules near the middle of the pump housing 1 pass through the radiation baffle 302 and continue to move downward.

[0025] After entering the pump casing 1, some gas molecules move downwards along the space between the outermost radiation baffle 302 and the inner wall of the pump casing 1 until they come into contact with the guide ring 7. They are then guided by the guide ring 7 to the space between the corresponding two heat-absorbing rings 6. Water vapor and some high-boiling-point gases in these gas molecules are captured by the heat-absorbing rings 6, thus condensing from a gaseous state into a solid state. Since the outer diameter of the equally spaced guide rings 7 gradually increases from top to bottom, it evenly guides the gas molecules near the inner wall of the pump casing 1 to the spaced heat-absorbing rings 6, ensuring a uniform distribution of gas molecules and improving the capture efficiency of the heat-absorbing rings 6. Simultaneously, the equally spaced heat-absorbing rings 6 are all located outside the condensation array 402, allowing the heat-absorbing rings 6 to shield the heat radiation from the inner wall of the pump casing 1, thus protecting the gas molecules. The secondary cold head 401 and the condenser array 402 are protected. Since the vertical cross-section of the heat-absorbing ring 6 is a V-shape with the opening facing downwards, the heat radiation from the pump housing 1 is reflected between adjacent heat-absorbing rings 6, thereby increasing the amount of shielded heat radiation. Gas molecules passing through the heat-absorbing ring 6 move towards the condenser array 402. Finally, the gas molecules moving downwards and gathering towards the center come into contact with the condenser array 402. The condenser array 402 captures gases such as nitrogen, oxygen, and argon in the gas molecules, causing these gases to condense from a gaseous state into a solid state. The condenser array 402 is generally covered with a layer of adsorbent with a very high surface area, thereby adsorbing hydrogen and helium, which are difficult to condense. The pumping process of the cryogenic vacuum pump is to convert gas molecules into solids and store them in the pump housing 1.

[0026] The heat-absorbing rings 6 installed on the outside of the condenser array 402 replace the radiant baffles 302 near the inner wall of the pump casing 1, making full use of the space between the condenser array 402 and the inner wall of the pump casing 1, thus improving the space utilization rate inside the pump casing 1. Since the space between the condenser array 402 and the inner wall of the pump casing 1 is larger than the space occupied by the radiant baffles 302 near the inner wall of the pump casing 1, the surface area of ​​the equally spaced heat-absorbing rings 6 is larger than the surface area of ​​the radiant baffles near the inner wall of the pump casing 1. This not only increases the amount of gas captured but also effectively shields the heat radiation from the inner wall of the pump casing 1. Furthermore, the width of the gap between the heat-absorbing rings 6 and the condenser array 402 is equal to the distance between the radiant baffles 302 and the condenser array 402, ensuring a high pumping speed for gas molecules (if the existing installation method of the radiant baffles 302 is used, the gas molecules passing through the radiant baffles 302 near the inner wall of the pump casing 1 are more difficult to pump than the gas molecules moving downwards in the middle). (Contact with condenser array 402, thus reducing pumping speed). During gas extraction, a solid layer forms on radiant baffle 302, heat-absorbing ring 6, and condenser array 402, causing the subsequent gas extraction speed to gradually decrease. After gas extraction is complete, a regeneration operation is performed. The operator closes the inlet 201 and isolates it from the vacuum system, while stopping the primary and secondary refrigeration modules. This raises the temperature of the primary cold head 301, radiant baffle 302, secondary cold head 401, condenser array 402, and heat-absorbing ring 6 to room temperature. The exhaust port 101 is then opened, and the condensed gas desorbs. The desorbed gas on radiant baffle 302, condenser array 402, and heat-absorbing ring 6 flows down through the gap between heat-absorbing ring 6 and condenser array 402 and is drawn away by the auxiliary backing pump through exhaust port 101. After all the gas is discharged, the refrigeration is restarted, and the cryogenic vacuum pump can work again. Example 2

[0027] During the process of gas molecules being captured by the heat-absorbing ring 6, a solid layer is formed on the heat-absorbing ring 6 as the gas molecules are captured. This reduces the shielding effect of the heat-absorbing ring 6 on the thermal radiation of the inner wall of the pump casing 1 (because the outer surface of the heat-absorbing ring 6 is partially blocked by the solid layer, the part of the heat-absorbing ring 6 blocked by the solid layer cannot directly contact the thermal radiation). It also reduces the amount of gas molecules captured between adjacent heat-absorbing rings 6 (because the outer surface of the heat-absorbing ring 6 is partially blocked by the solid layer, the ability of the heat-absorbing ring 6 to capture gas is reduced, causing the heat-absorbing ring 6 to be unable to directly capture the gas between two heat-absorbing rings 6, thereby reducing the area of ​​the heat-absorbing ring 6 that can capture gas).

[0028] Based on Example 1, a high-sealing, large-diameter cryogenic vacuum pump, such as... Figures 2-4As shown, a rotating ring 8, coaxial with the heat-absorbing ring 6, is rotatably connected to the lower side of the pump casing 1. The pump casing 1 is equipped with a power module for driving the rotating ring 8 to rotate. The power module can be a motor (not shown in the figure) installed on the pump casing 1. The output shaft of the motor is driven by a gear set to the rotating ring 8. Two symmetrically distributed arc-shaped plates 9 are fixedly connected to the rotating ring 8. The arc-shaped plates 9 are located between the equally spaced heat-absorbing rings 6 and the condensing array 402. The arc-shaped plates 9 are provided with equally spaced sliding grooves 901. Two symmetrically distributed connecting rods 10 are fixedly connected to the inner ring surface of the heat-absorbing ring 6. The connecting rods 10 slide in adjacent sliding grooves 901. The sliding grooves 901 are inclined grooves. The equally spaced heat-absorbing rings 6 are all slidably connected to the fixed plate 5. The arc-shaped plates 9 drive the equally spaced sliding grooves 901 on them to rotate. The connecting rods 10 with their spacing distribution move upward, causing the adjacent heat-absorbing rings 6 to move upward. The inclination angle of the equally spaced sliding grooves 901 on the same arc plate 9 gradually increases from top to bottom, so that the spacing between adjacent heat-absorbing rings 6 keeps decreasing synchronously, thereby achieving uniform capture of gas molecules. The outer diameter of the bottommost guide ring 7 is equal to the inner diameter of the pump housing 1, guiding the gas molecules moving downward close to the inner wall of the pump housing 1, ensuring that these gas molecules can enter between the corresponding two heat-absorbing rings 6. The pump housing 1 is provided with an annular groove 102, which is located above the bottommost guide ring 7. When the bottommost guide ring 7 is flush with the middle of the annular groove 102, the gas molecules in the pump housing 1 move downward through the gap between the bottommost guide ring 7 and the annular groove 102 and are discharged from the pump housing 1.

[0029] To solve the above problems, the specific process is as follows: During the process of capturing gas molecules, the operator drives the rotating ring 8 to rotate clockwise via the power module. Figure 3 (Top view direction) The rotating ring 8 drives the two arc-shaped plates 9 to rotate clockwise. Taking the right arc-shaped plate 9 as an example, the arc-shaped plate 9 drives the equally spaced connecting rods 10 to move upward through the equally spaced sliding grooves 901 on it. The connecting rods 10 drive the adjacent heat-absorbing rings 6 to move upward, and the heat-absorbing rings 6 drive the adjacent guide rings 7 to move upward. The lowest guide ring 7 is in close contact with the inner wall of the pump casing 1 and close to the annular groove 102. During the upward movement of the equally spaced heat-absorbing rings 6, the setting of the inclination angle of the equally spaced sliding grooves 901 on the same arc-shaped plate 9 gradually increasing from top to bottom makes the upward movement speed of the equally spaced heat-absorbing rings 6 increase from top to bottom. This ensures that the distance between two adjacent heat-absorbing rings 6 keeps decreasing synchronously, thereby achieving uniform capture of gas molecules. Moreover, the decrease in the distance between adjacent heat-absorbing rings 6 increases the number of times thermal radiation bounces between adjacent heat-absorbing rings 6, thereby increasing the shielding amount of thermal radiation. This compensates for the impact of the reduction in the area of ​​thermal radiation shielded by the heat-absorbing rings 6 due to the shielding of the solid layer.

[0030] The reduced spacing between adjacent heat-absorbing rings 6 decreases the distance between gas molecules and the surface of the heat-absorbing rings 6, and shortens the distance between gas molecules in the middle of the heat-absorbing rings 6 and the heat-absorbing rings 6, making it easier for the heat-absorbing rings 6 to capture gas molecules. This increases the amount of gas molecules captured by the part of the heat-absorbing rings 6 not blocked by the solid layer (the heat-absorbing rings 6 are more likely to capture closer gas molecules). When the gas extraction is complete, the spacing between adjacent heat-absorbing rings 6 reaches its minimum, the lowermost guide ring 7 is aligned with the middle of the annular groove 102, and a gap is formed between the lowermost guide ring 7 and the inner wall of the pump casing 1. After the gas on the heat-absorbing rings 6 is desorbed, the gas on the heat-absorbing rings 6 moves downward through the gap between the lowermost guide ring 7 and the inner wall of the pump casing 1, and is finally discharged from the pump casing 1 through the exhaust port 101. This increases the exhaust channel for the gas on the heat-absorbing rings 6, making it easier for the gas in the pump casing 1 to be discharged. After the gas molecules in the pump casing 1 are discharged, the operator drives the rotating ring 8 to rotate counterclockwise through the control module. Figure 3 (Top view direction) The rotating ring 8 drives the two arc-shaped plates 9 to rotate counterclockwise. The equally spaced heat-absorbing rings 6 all move downwards, and the distance between adjacent heat-absorbing rings 6 increases. When the distance between adjacent heat-absorbing rings 6 returns to the initial state, the operator stops the power module.

[0031] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present application. Therefore, the content of this specification should not be construed as a limitation of the present application.

Claims

1. A high-sealing, large-diameter cryogenic vacuum pump, comprising a pump housing (1), a top cover (2) mounted on the upper side of the pump housing (1), an exhaust port (101) provided on the lower side of the pump housing (1), an air inlet (201) communicating with the pump housing (1) provided on the top cover (2), a primary cold head (301) and several radiation baffles (302) with gradually increasing radii provided on the upper side inside the pump housing (1), two adjacent radiation baffles (302), the innermost radiation baffle (302) and the primary cold head (301) being connected to the outermost radiation baffle (302) and the pump housing (1) by connectors (303), and a secondary cold head (401) and a condensation array (402) provided on the lower side of the pump housing (1), characterized in that, The pump housing (1) is fixedly connected to a fixing plate (5). The fixing plate (5) is provided with heat-absorbing rings (6) that are evenly distributed at the top and bottom and are all located on the outside of the condensing array (402). The material of the heat-absorbing rings (6) is the same as that of the radiant baffle (302). The pump housing (1) is provided with a primary refrigeration module for cooling the primary cold head (301), the radiant baffle (302) and the heat-absorbing rings (6). The pump housing (1) is provided with a secondary refrigeration module for cooling the secondary cold head (401) and the condensing array (402).

2. The high-sealing, large-diameter cryogenic vacuum pump according to claim 1, characterized in that, The distance between the radiation baffle (302) and the condensation array (402) is equal to the width of the gap between the heat absorption ring (6) and the condensation array (402).

3. The high-sealing, large-diameter cryogenic vacuum pump according to claim 1, characterized in that, There is a gap between the outermost radiation baffle (302) and the inner wall of the pump casing (1).

4. The high-sealing, large-diameter cryogenic vacuum pump according to claim 1, characterized in that, The heat-absorbing ring (6) has a vertical cross-section that is V-shaped with the opening facing downwards.

5. A high-sealing, large-diameter cryogenic vacuum pump according to claim 4, characterized in that, A flow guide ring (7) is fixed to the outside of the heat absorption ring (6) to guide the gas between the two corresponding heat absorption rings (6).

6. A high-sealing, large-diameter cryogenic vacuum pump according to claim 5, characterized in that, The height of the outer ring of the guide ring (7) is higher than the height of its inner ring.

7. A high-sealing, large-diameter cryogenic vacuum pump according to claim 6, characterized in that, The outer diameter of the equally spaced guide rings (7) gradually increases from top to bottom.

8. A high-sealing, large-diameter cryogenic vacuum pump according to claim 6, characterized in that, A rotating ring (8) is rotatably connected inside the pump housing (1). The pump housing (1) is provided with a power module for driving the rotating ring (8) to rotate. The rotating ring (8) is fixed with symmetrically distributed arc plates (9). The arc plates (9) are provided with equally spaced sliding grooves (901). The heat-absorbing ring (6) is fixed with symmetrically distributed connecting rods (10) on the side close to the condenser array (402). The connecting rods (10) slide in the adjacent sliding grooves (901). The sliding grooves (901) are inclined grooves. The equally spaced heat-absorbing rings (6) are all slidably connected to the fixed plate (5).

9. A high-sealing, large-diameter cryogenic vacuum pump according to claim 8, characterized in that, The inclination angle of the grooves (901) distributed at equal intervals on the same curved plate (9) gradually increases from top to bottom.

10. A high-sealing, large-diameter cryogenic vacuum pump according to claim 8, characterized in that, The outer diameter of the bottommost guide ring (7) is equal to the inner diameter of the pump housing (1). The pump housing (1) is provided with an annular groove (102), which is located above the bottommost guide ring (7).

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