Two-stage ultrahigh vacuum differential air extractor based on low-temperature air extraction cold plate

Abstract

The invention discloses a two-stage ultrahigh vacuum differential air extractor based on a low-temperature air extraction cold plate, which comprises a vacuum container, a central partition plate is mounted in the vacuum container, and the central partition plate divides the vacuum container into a first-stage differential area and a second-stage differential area; a first-stage air extraction cooling plate and a second-stage air extraction cooling plate are mounted in each of the first-stage differential region and the second-stage differential region and are used for extracting air in the differential region so as to adjust the vacuum degree of the differential region; a flange connector is arranged on the side portion of the vacuum container, a GM small refrigerator is installed in the flange connector, and the GM small refrigerator is connected with the first-stage air pumping cooling plate and the second-stage air pumping cooling plate and used for providing a low-temperature environment for the vacuum container. The differential air extractor has the beneficial effects that the differential air extractor can be communicated with other low-vacuum environment equipment, and an ultrahigh vacuum environment can be obtained in a secondary differential area after refrigeration is completed; in addition, the differential air extractor is simple in structure, small in size and free of air vibration interference in the using process.

Description

Technical Field

[0001] The present application relates to the field of low-temperature vacuum technology, and in particular to a two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate. Background Art

[0002] In vacuum experimental devices involving particle motion, it is necessary to ensure a local ultra-high vacuum environment in the particle motion path to reduce the interference of gas molecules on the experimental process, such as molecular beam mass spectrometry devices, accelerator devices, particle collision devices, etc. In order to achieve a multi-level vacuum environment in a complex vacuum system, it is necessary to design a differential device to achieve vacuum chambers with different pressures. The differential device not only needs to effectively isolate the pressure gradient, but also reduce the impact on the vacuum degree while ensuring the stable operation of the system.

[0003] Differential pumping technology is a key technology used to achieve high vacuum and ultra-high vacuum environments in local vacuum chambers. The key to differential pumping is to gradually reduce the pressure in the system through different levels of pumping areas to achieve the final required vacuum pressure. Differential pumping usually uses high vacuum pumps such as molecular pumps and ion pumps as the main pumps, and forms a pressure gradient inside the vacuum chamber through the throttling effect of small holes to achieve the required vacuum degree. However, the use of these vacuum pumps also brings problems such as large size and vibration interference, which may affect the overall performance of the instrument.

[0004] The differential pumping system is usually composed of multiple vacuum chambers connected by narrow through holes. In chambers of different levels, the pumping equipment reduces the pressure in the vacuum container, and the small holes between the containers enable the limited flow of gas molecules from the adjacent level containers. As the level of the container increases, the ultimate pressure in the container decreases, and the vacuum degree gradually increases, and finally the required high vacuum or ultra-high vacuum level is achieved in the container of the last level. Summary of the invention

[0005] One of the objects of the present application is to provide a two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate that can solve at least one of the defects in the above-mentioned background technology.

[0006] In order to achieve at least one of the above-mentioned purposes, the technical solution adopted in the present application is: a two-stage ultra-high vacuum differential pumping device based on a low-temperature air pumping cold plate, comprising a vacuum container, a central partition installed in the vacuum container, and the central partition divides the vacuum container into a primary differential area and a secondary differential area; a primary air pumping cold plate and a secondary air pumping cold plate are installed in the primary differential area and the secondary differential area, which are used to extract air in the differential area to adjust the vacuum degree of the differential area; a flange interface is provided on the side of the vacuum container, and a GM small refrigerator is installed in the flange interface, and the GM small refrigerator is connected to the primary air pumping cold plate and the secondary air pumping cold plate to provide a low-temperature environment for the vacuum container.

[0007] Through the above settings, the vacuum container can be divided into two areas. By simply adjusting the air extraction efficiency of the first-stage air extraction cold plate and the second-stage air extraction cold plate in each area, different vacuum degrees can be formed in the two areas. The GM small refrigerator can cool the first-stage air extraction cold plate and the second-stage air extraction cold plate. By lowering the temperature in the vacuum container, the movement of gas molecules in the container is slowed down, the collision frequency is reduced, and the number of gas molecules is reduced, so that the vacuum container reaches a higher vacuum degree. The GM small refrigerator has the advantages of simple structure and high efficiency in the field of low-temperature cooling, which can reduce the volume and weight of the device and increase portability.

[0008] Preferably, the GM small refrigerator directly contacts the primary air extraction cold plate through bolts for cooling; a support plate is installed on the secondary air extraction cold plate, and the GM small refrigerator is connected to the support plate and conducts cold energy to the secondary air extraction cold plate. Through the above arrangement, on the one hand, the primary air extraction cold plate and the secondary air extraction cold plate can be fixedly installed on the GM small refrigerator; on the other hand, the cold energy of the GM small refrigerator can be quickly conducted to the primary air extraction cold plate or the secondary air extraction cold plate through bolts or support plates, so as to reduce the loss of cold energy during the conduction process.

[0009] Preferably, the support plate is in a "double T" shape to increase the contact surface between the secondary air extraction cold plate and the GM small refrigerator. Through the above arrangement, the cooling effect of the GM small refrigerator on the secondary air extraction cold plate can be significantly improved.

[0010] Preferably, the vacuum container is cylindrical, and the outer contours of the first-stage air extraction cold plate and the second-stage air extraction cold plate are consistent with the inner contour of the vacuum container, so as to increase the effective space in the vacuum container. Through the above arrangement, the vacuum area in the vacuum container can be increased to the maximum extent.

[0011] Preferably, the axes of the primary air extraction cold plate and the secondary air extraction cold plate are respectively provided with a first through hole and a second through hole aligned with each other to ensure that the particle movement path in the axis direction is not affected. Through the above arrangement, particles can enter the secondary air extraction cold plate from the primary air extraction cold plate, so that the particles pass through the through holes in a straight line, avoiding collision between the particles and the air extraction cold plate during movement.

[0012] Preferably, the material of the central partition includes but is not limited to stainless steel, and the thickness of the central partition is 3mm to 7mm; a differential circular hole coaxial with the first through hole and the second through hole is provided at the axis of the central partition, and the diameter of the differential circular hole is 15mm to 25mm. Through the above arrangement, the central partition is prevented from rusting under long-term use, and the differential circular hole on the central partition makes the secondary differential area conductive with the secondary differential area; particles can enter other differential areas through the differential circular hole.

[0013] Preferably, the thickness of the central partition is 5 mm, and the diameter of the differential circular hole is 20 mm.

[0014] Preferably, a ventilation circular plate is installed on the first-stage air extraction cold plate, and a plurality of ventilation holes are arranged on the ventilation circular plate, so that gas molecules can move and transfer from the higher pressure side through the ventilation holes to the second-stage air extraction cold plate. Through the above arrangement, after the first-stage air extraction cold plate is cooled by the GM refrigeration mechanism, the gas molecules moving from the higher pressure side will be pre-cooled when passing through the first-stage air extraction cold plate, and at the same time, the first-stage air extraction cold plate will adsorb water molecules generated by degassing on the wall of the vacuum container.

[0015] Preferably, activated carbon is adhered to the surface of the secondary air extraction cold plate to increase the air suction capacity of the secondary air extraction cold plate, so as to increase the maintenance time of the vacuum degree in the vacuum container.

[0016] Preferably, the first differential region is provided with a first interface and a first mounting port, and the second differential region is provided with a second interface and a second mounting port; a vacuum pump is installed in the first interface and the second interface, and a high vacuum gauge is installed in the first mounting port and the second mounting port; a test interface is provided on the vacuum container, and the test interface is in conduction with the interior of the vacuum container. Through the above arrangement, the vacuum pump can provide power to the vacuum cold plate and the second vacuum cold plate to extract the gas in the vacuum container; the high vacuum gauge can measure the vacuum degree in the first differential region and the second differential region in real time and feed back the vacuum degree to the operator; the sample to be tested can enter the vacuum container through the test interface for testing.

[0017] Compared with the prior art, the beneficial effects of this application are:

[0018] A primary air extraction cold plate and a secondary air extraction cold plate are installed in each differential area, which can be connected to a vacuum pump through an interface on the side wall of the vacuum container for air extraction, so as to form different vacuum degrees in different differential areas according to actual needs; in addition, the differential exhaust device can also be connected with other low vacuum environment equipment. As the differential area increases, a vacuum gradient can be effectively formed in different areas of the vacuum container, and an ultra-high vacuum environment can be achieved in the terminal differential area.

[0019] GM small refrigerators have the advantages of simple structure and high efficiency in the field of low-temperature cooling. By using GM small refrigerators, a low-temperature pumping surface can be constructed in a vacuum container, and a two-stage or multi-stage differential structure can be designed in combination with the differential pumping method, which can effectively isolate the pressure in different areas of the vacuum container and achieve an ultra-high vacuum environment in local areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate in this application.

[0021] Figure 2 This is a schematic diagram of the structure of the first-stage air extraction cold plate in this application.

[0022] Figure 3 This is a schematic diagram of the structure of the two-stage air extraction cold plate in this application.

[0023] Figure 4 This is a schematic diagram of the external interface of the two-stage ultra-high vacuum differential pumping device based on the low-temperature pumping cold plate in this application.

[0024] In the figure: 1. vacuum container; 11. primary differential area; 12. secondary differential area; 13. flange interface; 14. test interface; 100. GM small refrigerator; 110. first interface; 111. first mounting port; 120. second interface; 121. second mounting port; 2. center partition; 21. differential circular hole; 3. primary air extraction cold plate; 31. ventilation circular plate; 32. first through hole; 33. ventilation hole; 4. secondary air extraction cold plate; 41. support plate; 42. second through hole. DETAILED DESCRIPTION

[0025] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0026] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present application.

[0027] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0028] The terms "including" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0029] One aspect of the present application provides a two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate, such as Figure 1 As shown, one preferred embodiment includes a vacuum container 1; a central partition plate 2 is installed in the vacuum container 1, which is used to divide the interior of the vacuum container 1 into a primary differential area 11 and a secondary differential area 12. A primary air extraction cold plate 3 and a secondary air extraction cold plate 4 are installed in the primary differential area 11 and the secondary differential area 12, which are used to extract air in the primary differential area 11 and the secondary differential area 12, so as to adjust the vacuum degree in the differential area.

[0030] It should be added that the vacuum container 1 , the primary air extraction cold plate 3 and the secondary air extraction cold plate 4 can be designed into different shapes such as a cuboid or a cylinder according to experimental requirements.

[0031] It is understandable that the operator only needs to adjust the air extraction efficiency of the primary air extraction cold plate 3 and the secondary air extraction cold plate 4 in each differential area to form different vacuum degrees in each differential area.

[0032] Further, such as Figure 1As shown, a flange interface 13 is provided on the side of the vacuum container 1 for installing a GM small refrigerator 100. The GM small refrigerator 100 is connected to the primary air extraction cold plate 3 and the secondary air extraction cold plate 4, and cools the primary air extraction cold plate 3 and the secondary air extraction cold plate 4 by transmitting cold energy, thereby providing a low temperature environment for the vacuum container 1.

[0033] It is understandable that the GM small refrigerator 100 reduces the temperature in the vacuum container 1, thereby slowing down the movement of gas molecules in the vacuum container 1 and reducing the collision frequency, thereby reducing the number of gas molecules and achieving a higher vacuum degree inside the vacuum container 1.

[0034] It should be noted that the GM small refrigerator 100 used in the present application has the advantages of simple structure and high efficiency in the field of low-temperature cooling, thereby reducing the volume and weight of the device and increasing portability.

[0035] Specifically, Figure 1 and Figure 2 As shown, the GM small refrigerator 100 directly contacts the primary air extraction cold plate 3 through bolts to perform cooling; a support plate 41 is installed on the secondary air extraction cold plate 4, and the GM small refrigerator 100 is connected to the support plate 41 and transmits cold energy to the secondary air extraction cold plate 4 to perform cooling on the secondary air extraction cold plate 4. Among them, the primary air extraction cold plate 3 can be fixedly installed on the GM small refrigerator 100 through bolts; the secondary air extraction cold plate 4 can be fixedly installed on the GM small refrigerator 100 through the support plate 41.

[0036] It should be noted that in order to reduce the loss of cold during conduction, the material of the bolts and the support plate 41 should have good thermal conductivity. In some embodiments of the present application, the material of the bolts and the support plate 41 is oxygen-free copper.

[0037] In this embodiment, if Figure 2 As shown, the support plate 41 is in a “double T” shape, which is used to increase the contact surface between the secondary air extraction cold plate 4 and the GM small refrigerator 100 , and further improve the cooling effect of the GM small refrigerator 100 on the secondary air extraction cold plate 4 .

[0038] In this embodiment, if Figure 1 , Figure 2 and Figure 3 As shown, the shape of the vacuum container 1 is cylindrical, and the outer contours of the primary air extraction cold plate 3 and the secondary air extraction cold plate 4 are consistent with the inner contour of the vacuum container 1, so as to increase the effective space in the vacuum container 1 and maximize the vacuum area in the vacuum container 1.

[0039] It should be known that during the experiment, the particles need to be transmitted through the primary air extraction cold plate 3 and the secondary air extraction cold plate 4, and during the transmission process, it must be ensured that the particles will not collide with the primary air extraction cold plate 3 and the secondary air extraction cold plate 4, otherwise it will seriously affect the accuracy of the experiment.

[0040] Therefore, in some embodiments of the present application, Figure 2 and Figure 3 As shown, the first through hole 32 and the second through hole 42 are respectively arranged at the axis of the primary air extraction cold plate 3 and the secondary air extraction cold plate 4 to ensure that the particle movement path in the axis direction is not affected. Particles can enter the secondary air extraction cold plate 4 from the primary air extraction cold plate 3. Since the first through hole 32 is aligned with the second through hole 42, it is ensured that the particles can pass through the first through hole 32 and the second through hole 42 in a straight line, avoiding the collision of the particles with the air extraction cold plate during movement and causing losses.

[0041] In some embodiments of the present application, the thickness of the central partition 2 is 3 mm to 7 mm, preferably 5 mm, to ensure that the central partition 2 has a high structural strength; in addition, in order to prevent the central partition 2 from rusting after long-term use, the central partition 2 is preferably made of materials that are not easy to rust, such as stainless steel.

[0042] In this embodiment, if Figure 1 As shown, the central partition plate 2 is provided with a differential circular hole 21 aligned with the first through hole 32 and the second through hole 42, so that the primary differential region 11 is connected to the secondary differential region 12, and particles can enter other differential regions through the differential circular hole 21. In order to prevent the particles from deflecting or colliding during the transmission process, the diameter of the differential circular hole 21 is set to 15 mm to 25 mm; preferably, the diameter is 20 mm.

[0043] In this embodiment, if Figure 1 and Figure 3 As shown, the secondary air extraction cold plate 4 is located inside the primary air extraction cold plate 3, and the primary air extraction cold plate 3 is close to the inner wall of the vacuum container 1. A ventilation circular plate 31 is installed on the primary air extraction cold plate 3, and a plurality of ventilation holes 33 are arranged on the ventilation circular plate 31, so that gas molecules can move and transmit from the higher pressure side to the secondary air extraction cold plate 4. After the primary air extraction cold plate 3 is cooled by the GM small refrigerator 100, the gas molecules moving from the higher pressure side will be pre-cooled when passing through the primary air extraction cold plate 3. At the same time, the primary air extraction cold plate 3 will adsorb water molecules generated by wall degassing, etc., to prevent water molecules from entering the vacuum area and interfering with the experiment.

[0044] It should be added that the shape of the vent hole 33 can be circular or polygonal, as long as the ventilation efficiency can meet the experimental requirements.

[0045] Furthermore, activated carbon is adhered to the surface of the secondary air extraction cold plate 4 to increase the air suction capacity of the secondary air extraction cold plate 4 , thereby increasing the maintenance time of the vacuum degree in the vacuum container 1 .

[0046] In this embodiment, if Figure 4 As shown, the primary differential region 11 is provided with a first interface 110 and a first mounting port 111, and the secondary differential region 12 is provided with a second interface 120 and a second mounting port 121; vacuum pumps are installed in the first interface 110 and the second interface 120, which are used to provide power for the primary air extraction cold plate 3 and the secondary air extraction cold plate 4 to extract the gas in the vacuum container 1. High vacuum gauges are installed in the first mounting port 111 and the second mounting port 121, and the vacuum degree in the primary differential region 11 and the secondary differential region 12 can be surveyed in real time through the high vacuum gauge and the vacuum degree can be fed back to the operator, so as to facilitate the subsequent adjustment of the vacuum degree.

[0047] Specifically, Figure 4 As shown, a test interface 14 is provided on the vacuum container 1 , and the test interface 14 is connected to the interior of the vacuum container 1 , and the sample to be tested can enter the vacuum container 1 through the test interface 14 for testing.

[0048] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate, comprising a vacuum container (1), characterized in that: A central partition (2) is installed in the vacuum container (1), and the central partition (2) divides the vacuum container (1) into a primary differential region (11) and a secondary differential region (12); a primary air extraction cold plate (3) and a secondary air extraction cold plate (4) are installed in the primary differential region (11) and the secondary differential region (12), and are used to extract air in the differential region to adjust the vacuum degree of the differential region; a flange interface (13) is provided on the side of the vacuum container (1), and a GM small refrigerator (100) is installed in the flange interface (13); the GM small refrigerator (100) is connected to the primary air extraction cold plate (3) and the secondary air extraction cold plate (4), and is used to provide a low-temperature environment for the vacuum container (1).

2. The two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate according to claim 1 is characterized in that: The GM small refrigerator (100) directly contacts the primary air extraction cold plate (3) via bolts to perform cooling; a support plate (41) is installed on the secondary air extraction cold plate (4), and the GM small refrigerator (100) is connected to the support plate (41) and conducts cold energy to the secondary air extraction cold plate (4).

3. The two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate according to claim 2 is characterized in that: The support plate (41) is in a "double T" shape so as to increase the contact surface between the secondary air extraction cold plate (4) and the GM small refrigerator (100).

4. The two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate according to claim 1 is characterized in that: The vacuum container (1) is cylindrical, and the outer contours of the first-stage air extraction cold plate (3) and the second-stage air extraction cold plate (4) are consistent with the inner contour of the vacuum container (1), so as to increase the effective space in the vacuum container (1).

5. The two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate according to claim 1 is characterized in that: A first through hole (32) and a second through hole (42) aligned with each other are respectively provided at the axis of the primary air extraction cold plate (3) and the secondary air extraction cold plate (4) to ensure that the particle movement path in the axis direction is not affected.

6. The two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate according to claim 1 or 5, characterized in that: The material of the central partition (2) includes but is not limited to stainless steel, and the thickness of the central partition (2) is 3 mm to 7 mm; a differential circular hole (21) coaxial with the first through hole (32) and the second through hole (42) is provided at the axis of the central partition (2), and the diameter of the differential circular hole (21) is 15 mm to 25 mm.

7. The two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate according to claim 6, characterized in that: The thickness of the central partition (2) is 5 mm, and the diameter of the differential circular hole (21) is 20 mm.

8. The two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate according to claim 1, characterized in that: The first-stage air extraction cold plate (3) is provided with a ventilation circular plate (31), and the ventilation circular plate (31) is provided with a plurality of ventilation holes (33), so that gas molecules can be transported from the higher pressure side through the ventilation holes (33) toward the second-stage air extraction cold plate (4).

9. The two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate according to claim 1, characterized in that: Activated carbon is adhered to the surface of the secondary air extraction cold plate (4) and is used to increase the air suction capacity of the secondary air extraction cold plate (4) so ​​as to increase the maintenance time of the vacuum degree in the vacuum container (1).

10. The two-stage ultra-high vacuum differential pumping device based on a low-temperature pumping cold plate according to claim 1, characterized in that: The primary differential region (11) is provided with a first interface (110) and a first mounting port (111), and the secondary differential region (12) is provided with a second interface (120) and a second mounting port (121); a vacuum pump is installed in the first interface (110) and the second interface (120), and a high vacuum gauge is installed in the first mounting port (111) and the second mounting port (121); and a test interface (14) is provided on the vacuum container (1), and the test interface (14) is in conduction with the interior of the vacuum container (1).

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