Two-stage ultra-high vacuum differential pumping device based on low-temperature pumping cold plate

Abstract

The application discloses a two-stage ultra-high vacuum differential pumping device based on low-temperature pumping cold plates, which comprises a vacuum container, a center partition plate is installed in the vacuum container, the center partition plate divides the vacuum container into a first-stage differential region and a second-stage differential region, a first-stage pumping cold plate and a second-stage pumping cold plate are installed in the first-stage differential region and the second-stage differential region, and are used for pumping air in the differential regions to adjust the vacuum degree of the differential regions; a flange interface is arranged on the side of the vacuum container, a GM small-sized refrigerator is installed in the flange interface, the GM small-sized refrigerator is connected with the first-stage pumping cold plate and the second-stage pumping cold plate, and is used for providing a low-temperature environment for the vacuum container. The differential pumping device can be connected with other low-vacuum environment equipment, an ultra-high vacuum environment can be obtained in the second-stage differential region after refrigeration is completed, the differential pumping device has the advantages of simple structure, small size and no gas vibration interference in the use process.

Description

TECHNICAL FIELD

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

[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 multi-stage vacuum environments in complex vacuum systems, differential devices need to be designed to achieve different pressure vacuum chambers. Differential devices not only need to effectively isolate the pressure gradient, but also need to reduce the impact on the vacuum degree while ensuring stable operation of the system.

[0003] Differential pumping technology is a key technology for achieving 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, thereby achieving the required final vacuum pressure. Differential pumping usually uses molecular pumps, ion pumps, and other high vacuum pumps as main pumping pumps, and forms a pressure gradient inside the vacuum chamber through the small hole throttling effect to achieve the required vacuum degree. However, the use of these vacuum pumps also brings problems such as large volume and vibration interference, which may affect the overall performance of the instrument.

[0004] Differential pumping systems are usually connected by multiple vacuum chambers, and different chambers are connected through narrow through holes. In different levels of chambers, the pressure inside the vacuum container is reduced by pumping equipment, and the limited flow of gas molecules from adjacent levels of containers is achieved through small holes between containers. With the increase of container levels, the ultimate pressure reached in the container is reduced, and the vacuum degree is gradually increased. Finally, the required high vacuum or ultra-high vacuum level is achieved in the last stage of the container. SUMMARY

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

[0006] To achieve the above at least one object, the technical scheme adopted by the present application is: a two-stage ultra-high vacuum differential pumping device based on low-temperature pumping cold plate, comprising a vacuum container, a center partition plate is installed in the vacuum container, the center partition plate divides the vacuum container into a first differential region and a second differential region; a first-stage pumping cold plate and a second-stage pumping cold plate are installed in the first differential region and the second differential region, respectively, for pumping air in the differential region to adjust the vacuum degree of the differential region; a flange interface is arranged on the side of the vacuum container, a GM small-sized refrigerator is installed in the flange interface, the GM small-sized refrigerator is connected with the first-stage pumping cold plate and the second-stage pumping cold plate, and is used for providing a low-temperature environment for the vacuum container.

[0007] Through the above arrangement, the vacuum container can be divided into two regions, and by adjusting the pumping efficiency of the first-stage pumping cold plate and the second-stage pumping cold plate in each region, different vacuum degrees can be formed in the two regions. The GM small-sized refrigerator can cool the first-stage pumping cold plate and the second-stage pumping cold plate, and by reducing 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 can achieve a higher vacuum degree. The GM small-sized 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 the portability.

[0008] Preferably, the GM small-sized refrigerator directly contacts the first-stage pumping cold plate through bolts to cool; a support plate is installed on the second-stage pumping cold plate, and the GM small-sized refrigerator is connected with the support plate and conducts cold to the second-stage pumping cold plate. Through the above arrangement, on the one hand, the first-stage pumping cold plate and the second-stage pumping cold plate can be fixedly installed on the GM small-sized refrigerator; on the other hand, the cold of the GM small-sized refrigerator can be quickly conducted to the first-stage pumping cold plate or the second-stage pumping cold plate through the bolts or the support plate, so as to reduce the loss of cold in the conduction process.

[0009] Preferably, the support plate is in the shape of "double T", so as to increase the contact surface between the second-stage pumping cold plate and the GM small-sized refrigerator. Through the above arrangement, the cooling effect of the GM small-sized refrigerator on the second-stage pumping cold plate can be significantly improved.

[0010] Preferably, the vacuum container is in the shape of a cylinder, and the outer contours of the first-stage pumping cold plate and the second-stage pumping 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 region in the vacuum container can be maximized.

[0011] Preferably, the first and second through holes are coaxially arranged at the axis of the primary and secondary gas-extraction cold plates respectively, so as to ensure the particle movement path in the axial direction is not affected. Through the above arrangement, the particles can enter the secondary gas-extraction cold plate from the primary gas-extraction cold plate, so that the particles pass through the through holes in a straight line, avoiding collision between the particles and the gas-extraction cold plates during movement.

[0012] Preferably, the material of the center partition plate includes but is not limited to stainless steel, and the thickness of the center partition plate is 3-7 mm. A differential circular hole coaxial with the first and second through holes is arranged at the axis of the center partition plate, and the diameter of the differential circular hole is 15-25 mm. Through the above arrangement, the center partition plate is prevented from rusting after long-term use, and the differential circular hole on the center partition plate enables the secondary differential region to be in conduction with the secondary differential region. The particles can enter other differential regions through the differential circular hole.

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

[0014] Preferably, a ventilation circular plate is mounted on the primary gas-extraction cold plate, and a plurality of ventilation holes are arranged on the ventilation circular plate, so that the gas molecules move and transmit from the higher pressure side to the secondary gas-extraction cold plate through the ventilation holes. Through the above arrangement, the gas molecules moving from the higher pressure side are preliminarily precooled after passing through the primary gas-extraction cold plate after being cooled by the GM refrigerator, and the primary gas-extraction cold plate adsorbs the water molecules on the wall of the vacuum container due to outgassing.

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

[0016] Preferably, a first interface and a first mounting port are arranged on the primary differential region, and a second interface and a second mounting port are arranged on the secondary differential region. A vacuum pump is mounted in the first and second interfaces, and a high vacuum gauge is mounted in the first and second mounting ports. A test interface is arranged on the vacuum container, and the test interface is in conduction with the inside of the vacuum container. Through the above arrangement, the vacuum pump can provide power for the gas-extraction cold plate and the secondary gas-extraction cold plate to extract the gas in the vacuum container. The high vacuum gauge can detect the vacuum degree in the primary and secondary differential regions 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 application has the following beneficial effects:

[0018] A first-stage gas-extracting cold plate and a second-stage gas-extracting cold plate are installed in each differential region, and can be connected to a vacuum pump through an interface on the side wall of the vacuum container to extract gas and form different vacuum degrees in different differential regions according to actual needs; in addition, the differential gas-extracting device can be connected to other low-vacuum environment equipment, and with the increase of the differential regions, a vacuum gradient can be effectively formed in different regions of the vacuum container, and an ultrahigh-vacuum environment can be realized in the terminal differential region.

[0019] The GM small refrigerating machine has the advantages of simple structure and high efficiency in the field of low-temperature cooling; by using the GM small refrigerating machine, a low-temperature gas-extracting surface can be constructed in the vacuum container, and a two-stage or multi-stage differential structure can be designed by combining the differential gas-extracting method, so as to effectively isolate the pressures of different regions of the vacuum container and realize an ultrahigh-vacuum environment in a local region. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 FIG. 1 is a structural schematic diagram of a two-stage ultrahigh-vacuum differential gas-extracting device based on a low-temperature gas-extracting cold plate in the present application.

[0021] Figure 2 FIG. 2 is a structural schematic diagram of a first-stage gas-extracting cold plate in the present application.

[0022] Figure 3 FIG. 3 is a structural schematic diagram of a second-stage gas-extracting cold plate in the present application.

[0023] Figure 4 FIG. 4 is an external interface schematic diagram of a two-stage ultrahigh-vacuum differential gas-extracting device based on a low-temperature gas-extracting cold plate in the present application.

[0024] In the figure: 1, vacuum container; 11, first-stage differential region; 12, second-stage differential region; 13, flange interface; 14, test interface; 100, GM small refrigerating machine; 110, first interface; 111, first mounting port; 120, second interface; 121, second mounting port; 2, center partition plate; 21, differential round hole; 3, first-stage gas-extracting cold plate; 31, air passage round plate; 32, first through hole; 33, air passage hole; 4, second-stage gas-extracting cold plate; 41, support plate; 42, second through hole. DETAILED DESCRIPTION

[0025] In the following, the present application will be further described in conjunction with specific embodiments, and it should be noted that the embodiments described below or the technical features thereof can be combined in any manner to form new embodiments without conflict.

[0026] In the description of the present application, it should be noted that for the orientation words, such as the terms "center", "transverse", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation and positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and cannot be understood as limiting the specific protection scope of the present application.

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

[0028] The terms "include" and "have" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] One aspect of the present application provides a two-stage ultra-high vacuum differential pumping device based on low-temperature pumping cold plates, as shown in Figure 1 A preferred embodiment includes a vacuum container 1; a central partition 2 is installed inside the vacuum container 1, which divides the interior of the vacuum container 1 into a first-stage differential region 11 and a second-stage differential region 12. A first-stage pumping cold plate 3 and a second-stage pumping cold plate 4 are installed in the first-stage differential region 11 and the second-stage differential region 12, respectively, for pumping air in the first-stage differential region 11 and the second-stage differential region 12, thereby adjusting the vacuum degree in the differential region.

[0030] It should be noted that the vacuum container 1, the first-stage pumping cold plate 3 and the second-stage pumping cold plate 4 can be designed into different shapes such as rectangular parallelepiped or cylinder according to experimental needs.

[0031] It can be understood that the operator only needs to adjust the pumping efficiency of the first-stage pumping cold plate 3 and the second-stage pumping cold plate 4 in each differential region, so as to form different vacuum degrees in each differential region.

[0032] Further, as shown in Figure 1As shown, the side of the vacuum container 1 is provided with a flange interface 13 for installing the GM small refrigerator 100. The GM small refrigerator 100 is connected with the first-stage gas-exhausting cold plate 3 and the second-stage gas-exhausting cold plate 4, and refrigerates the first-stage gas-exhausting cold plate 3 and the second-stage gas-exhausting cold plate 4 by transferring cold energy, thereby providing a low-temperature environment for the vacuum container 1.

[0033] It can be understood that the GM small refrigerator 100 reduces the temperature in the vacuum container 1, so that the gas molecule movement in the vacuum container 1 is slowed down, the collision frequency is reduced, and the number of gas molecules is reduced, so that the internal part of the vacuum container 1 reaches a higher vacuum degree.

[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, which can reduce the volume and weight of the device and increase the portability.

[0035] Specifically, as shown in Figure 1 and Figure 2 , the GM small refrigerator 100 directly contacts the first-stage gas-exhausting cold plate 3 by bolts to refrigerate; the second-stage gas-exhausting cold plate 4 is provided with a support plate 41, and the GM small refrigerator 100 is connected with the support plate 41 and transfers cold energy to the second-stage gas-exhausting cold plate 4 to refrigerate the second-stage gas-exhausting cold plate 4. Among them, the first-stage gas-exhausting cold plate 3 can be fixedly installed on the GM small refrigerator 100 by bolts; the second-stage gas-exhausting cold plate 4 can be fixedly installed on the GM small refrigerator 100 by the support plate 41.

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

[0037] In the present embodiment, as shown in Figure 2 , the support plate 41 is in the shape of a "double T", which is used to increase the contact surface between the second-stage gas-exhausting cold plate 4 and the GM small refrigerator 100, and further improve the refrigeration effect of the GM small refrigerator 100 on the second-stage gas-exhausting cold plate 4.

[0038] In the present embodiment, as shown in Figure 1 , Figure 2 and Figure 3 , the shape of the vacuum container 1 is cylindrical, and the outer contours of the first-stage gas-exhausting cold plate 3 and the second-stage gas-exhausting 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 understood that, in the experiment, the particles need to be transported from the first-stage gas-extraction cold plate 3 and the second-stage gas-extraction cold plate 4, and the particles need to be prevented from colliding with the first-stage gas-extraction cold plate 3 and the second-stage gas-extraction cold plate 4 during the transportation, otherwise the accuracy of the experiment will be seriously affected.

[0040] Therefore, in some embodiments of the present application, as shown in Figure 2 and Figure 3 , first through holes 32 and second through holes 42 are arranged on the axes of the first-stage gas-extraction cold plate 3 and the second-stage gas-extraction cold plate 4, respectively, to ensure that the particle movement path in the axial direction is not affected. The particles can enter the second-stage gas-extraction cold plate 4 from the first-stage gas-extraction cold plate 3, and since the first through holes 32 and the second through holes 42 are aligned, it is ensured that the particles can pass through the first through holes 32 and the second through holes 42 in a straight line, avoiding the loss caused by the collision between the particles and the gas-extraction cold plate during the movement.

[0041] In some embodiments of the present application, the thickness of the center partition plate 2 is 3 mm to 7 mm, and preferably 5 mm, to ensure that the center partition plate 2 has high structural strength; in addition, in order to avoid rusting of the center partition plate 2 after long-term use, the center partition plate 2 is preferably made of a material that is not prone to rust, such as stainless steel.

[0042] In the present embodiment, as shown in Figure 1 , a differential circular hole 21 aligned with the first through holes 32 and the second through holes 42 is arranged on the center partition plate 2, so that the first-stage differential area 11 and the second-stage differential area 12 are conductive, and the particles can enter other differential areas through the differential circular hole 21. In order to avoid deviation or collision of the particles during the transportation, the diameter of the differential circular hole 21 is set to 15 mm to 25 mm; and preferably 20 mm.

[0043] In the present embodiment, as shown in Figure 1 and Figure 3 , the second-stage gas-extraction cold plate 4 is located inside the first-stage gas-extraction cold plate 3, and the first-stage gas-extraction cold plate 3 is close to the inner wall of the vacuum container 1. The first-stage gas-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 the gas molecules move and transport from the side of higher pressure to the second-stage gas-extraction cold plate 4. After the first-stage gas-extraction cold plate 3 is cooled by the GM small-sized refrigerator 100, the gas molecules moving from the side of higher pressure will be preliminarily cooled when passing through the first-stage gas-extraction cold plate 3, and at the same time, the first-stage gas-extraction cold plate 3 will adsorb the water molecules generated by wall gas release, avoiding the interference of the water molecules on the experiment in the vacuum area.

[0044] It should be noted that the shape of the ventilation hole 33 can be circular or polygonal, as long as the ventilation efficiency can meet the needs of the experiment.

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

[0046] In this embodiment, as Figure 4 As shown, the first-stage differential region 11 is provided with a first interface 110 and a first mounting port 111, and the second-stage 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 to provide power to the first-stage vacuum cooling plate 3 and the second-stage vacuum cooling plate 4, thereby extracting gas from the vacuum container 1. High-vacuum gauges are installed in the first mounting port 111 and the second mounting port 121. These gauges allow for real-time monitoring of the vacuum level in the first-stage differential region 11 and the second-stage differential region 12, and the vacuum level is fed back to the operator for subsequent adjustment.

[0047] Specifically, such as Figure 4 As shown, a test interface 14 is provided on the vacuum container 1. The test interface 14 is connected to the inside 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 basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A two-stage ultra-high vacuum differential pumping device based on cryogenic getter-cooled panels, comprising a vacuum vessel (1), characterized in that, The vacuum container (1) is provided with a center partition plate (2), which divides the vacuum container (1) into a first differential area (11) and a second differential area (12); the first differential area (11) and the second differential area (12) are provided with a first air extraction cold plate (3) and a second air extraction cold plate (4), which are used to extract air in the differential area to adjust the vacuum degree of the differential area; the side of the vacuum container (1) is provided with a flange interface (13), and the flange interface (13) is provided with a GM small-sized refrigerator (100), which is connected with the first air extraction cold plate (3) and the second air extraction cold plate (4) and is used to provide a low-temperature environment for the vacuum container (1); The GM small-sized refrigerator (100) directly contacts the first air extraction cold plate (3) through bolts to perform refrigeration; the second air extraction cold plate (4) is provided with a support plate (41), and the GM small-sized refrigerator (100) is connected with the support plate (41) and conducts cold energy to the second air extraction cold plate (4); the support plate (41) is in a "double-T" shape to increase the contact surface of the second air extraction cold plate (4) and the GM small-sized refrigerator (100); The first air extraction cold plate (3) and the second air extraction cold plate (4) are respectively provided with a first through hole (32) and a second through hole (42) at the axis, which are aligned with each other to ensure that the particle movement path in the axis direction is not affected; The first air extraction cold plate (3) is provided with an air passage circular plate (31), and the air passage circular plate (31) is provided with a plurality of air passage holes (33) to enable gas molecules to move and transmit from the higher pressure side to the second air extraction cold plate (4) through the air passage holes (33).

2. The two-stage ultra-high vacuum differential pumping apparatus based on cryogenic gas-getter cold plates of claim 1, wherein, The vacuum container (1) is in a cylindrical shape, and the outer contours of the first air extraction cold plate (3) and the second air extraction cold plate (4) are consistent with the inner contour of the vacuum container (1) to improve the effective space in the vacuum container (1).

3. The two-stage ultra-high vacuum differential pumping apparatus based on cryogenic gas-getter cold plates of claim 1, wherein, The material of the center partition plate (2) includes stainless steel, and the thickness of the center partition plate (2) is 3mm-7mm; the center partition plate (2) is provided with a differential circular hole (21) coaxial with the first through hole (32) and the second through hole (42) at the axis, and the diameter of the differential circular hole (21) is 15mm-25mm.

4. A two-stage ultra-high vacuum differential pumping apparatus based on cryogenic gas- gettering cold plates as claimed in claim 3, characterized in that, The thickness of the center partition plate (2) is 5mm, and the diameter of the differential circular hole (21) is 20mm.

5. The two-stage ultra-high vacuum differential pumping apparatus based on cryogenic gas- gettering cold plates of claim 1, wherein, The surface of the second air extraction cold plate (4) is adhered with activated carbon to increase the air absorption capacity of the second air extraction cold plate (4) and to increase the maintenance time of the vacuum degree in the vacuum container (1).

6. The two-stage ultra-high vacuum differential pumping apparatus based on cryogenic gas- gettering cold plates of claim 1, wherein, The first interface (110) and the first mounting port (111) are arranged on the first differential area (11), the second interface (120) and the second mounting port (121) are arranged on the second differential area (12); the vacuum pump is mounted in the first interface (110) and the second interface (120), the high vacuum gauge is mounted in the first mounting port (111) and the second mounting port (121); the test interface (14) is arranged on the vacuum container (1), and the test interface (14) is in communication with the inside of the vacuum container (1).

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