A compact GM refrigerator for ultra-high vacuum

Abstract

The present invention provides a compact GM refrigerator for ultra-high vacuum, comprising a GM refrigeration expander, an adapter flange, and a cold head, wherein one side of the adapter flange is connected to the GM refrigeration expander, and the other side is connected to the cold head, and the GM refrigeration expander is provided with a gas inlet and a gas outlet, characterized in that: the adapter flange comprises a large flange and a small flange; the small flange is connected to the large flange; a flange pipeline is provided on the small flange; and the number of the small flanges is two or more. The beneficial effects of the present invention are: providing a compact GM refrigerator for ultra-high vacuum, reducing the space required for the self-rotation of the sample holder, improving the compactness of the product, and thus realizing large-angle rotation.

Description

Technical Field

[0001] The invention relates to the field of experimental instruments, and in particular to a compact GM refrigerator for ultra-high vacuum. Background Art

[0002] GM refrigerator is a device that uses continuous adiabatic expansion to generate refrigeration. It consists of two parts: a helium compressor and an expander. Among them, the common expander has a two-stage cold head. The first cold head can achieve a low temperature of 45K, and the second cold head can achieve a low temperature of 4.2K. GM refrigerators have been widely used, mainly in cryogenic pumps, superconducting magnet cooling, helium liquefiers, and other devices that require a low temperature environment.

[0003] In the currently standardized GM refrigerator, the existing expander high-pressure helium hose is oriented horizontally (in the same direction as the motor). For a low-temperature sample rack using a GM refrigerator as a cooling source, it is not convenient to achieve large-angle rotation of the sample rack because the helium hose occupies a large space.

[0004] Therefore, the market is in urgent need of a refrigerator that can realize large-angle rotation of the sample rack. Summary of the invention

[0005] In order to solve the above technical problems, the present invention discloses a compact ultra-high vacuum GM refrigerator, and the technical solution of the present invention is implemented as follows:

[0006] A compact GM refrigerator for ultra-high vacuum, comprising a GM refrigeration expander, an adapter flange, and a cold head, wherein one side of the adapter flange is connected to the GM refrigeration expander, and the other side is connected to the cold head, and a gas inlet and a gas outlet are provided on the GM refrigeration expander, and the characteristics are: the adapter flange comprises a large flange and a small flange; the small flange is connected to the large flange; a flange pipe is provided on the small flange; and the number of the small flanges is two or more.

[0007] Preferably, a communication line and a rotating machine are installed in the flange pipeline; the communication line is connected to a sensor in a vacuum environment; and the rotating machine is connected to a moving part arranged in the vacuum environment.

[0008] Preferably, the communication line is a multi-core electrical feed-through for use in a vacuum; and the rotating machine adopts a bellows transmission.

[0009] Preferably, the small flange is connected to the large flange by welding.

[0010] Preferably, the large flange is a CF100 flange, and the small flange is a CF16 flange.

[0011] Preferably, a circumferential welding end face is provided on the large flange; the circumferential welding end face is connected to the GM refrigeration expander by welding.

[0012] Preferably, a wiring groove is provided at the connection; the communication line extends downward through the wiring groove.

[0013] Preferably, the cold head includes a primary cold head and a secondary cold head.

[0014] Preferably, the additional device setting hole is located at the connection between the primary cold head and the secondary cold head.

[0015] Preferably, the gas inlet and the gas outlet face upward.

[0016] The implementation of the technical solution of the present invention can solve the technical problems of insufficient compactness of the existing sample holder and excessive space required for the self-rotation of the sample holder; the implementation of the technical solution of the present invention can greatly reduce the space required for the self-rotation of the sample holder and improve the compactness of the product, thereby achieving the technical effect of large-angle rotation of the sample holder. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the overall structure of a compact GM refrigerator for ultra-high vacuum;

[0019] Figure 2 This is a schematic diagram of the adapter flange structure of a compact ultra-high vacuum GM refrigerator;

[0020] Figure 3 It is a schematic diagram of the structure of the connection between the first-stage cold head and the second-stage cold head of a compact ultra-high vacuum GM refrigerator;

[0021] Figure 4 It is a schematic diagram of the overall structure of a compact GM refrigerator for ultra-high vacuum;

[0022] Figure 5 The diagram is a schematic structural diagram of the connection between the primary cold head and the secondary cold head in an embodiment with a wiring groove of a compact ultra-high vacuum GM refrigerator.

[0023] In the above drawings, the figure numbers represent:

[0024] 1-GM refrigeration expander, 2-gas inlet, 3-gas outlet, 4-large flange, 5-small flange, 6-first-stage cold head, 7-second-stage cold head, 8-wiring trough. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In a specific embodiment, Figure 1-Figure 5 As shown, a compact GM refrigerator for ultra-high vacuum comprises a GM refrigeration expander (1), an adapter flange, and a cold head, wherein one side of the adapter flange is connected to the GM refrigeration expander (1), and the other side is connected to the cold head, and the GM refrigeration expander (1) is provided with a gas inlet (2) and a gas outlet (3), and is characterized in that: the adapter flange comprises a large flange (4) and a small flange (5); the small flange (5) is connected to the large flange (4); a flange pipe is provided on the small flange (5); and the number of the small flanges (5) is two or more.

[0027] In this specific embodiment, the GM refrigeration expander (1) is connected to the cold head via an adapter flange. When in use, the refrigeration gas, generally helium, enters from the gas inlet (2) and then flows out from the gas outlet (3). The inlet and outlet of the helium hose of a traditional refrigerator are long in the horizontal direction, which results in the space required for the sample holder to rotate too much and not compact enough. By changing the inlet and outlet direction of the helium to the vertical direction, the space required for the sample holder to rotate is reduced, the compactness of the product is improved, and a large angle rotation can be achieved.

[0028] In a preferred embodiment, Figure 1-Figure 3 As shown, the adapter flange includes a large flange (4) and a small flange (5); the small flange (5) is connected to the large flange (4); a flange pipe is provided on the small flange (5); the number of the small flanges (5) is two or more; a communication line and a rotating machine are installed in the flange pipe; the communication line is a multi-core electric feed-through for use in a vacuum; and the rotating machine adopts a bellows transmission.

[0029] In this preferred embodiment, in the prior art, in many cases people need to transfer various movements such as reciprocating motion, swinging, and rotational motion from outside the vacuum chamber into the vacuum chamber so that the motion mechanism in the vacuum chamber can meet the requirements of displacement, speed or force, but the existing GM refrigerator does not have a suitable structural design to realize such motion transmission inside and outside the vacuum, and cannot realize the corresponding signal transmission. In order to solve the above problems, a multi-core electrical feedthrough for vacuum is provided in the flange pipeline, which is connected to sensors including sensors, and transmits the data collected by the sensor to the outside to realize signal transmission inside and outside the vacuum; the rotating machine uses bellows transmission, which can realize various movements and has a larger bending range compared with the diaphragm transmission.

[0030] In a preferred embodiment, Figure 1-Figure 3 As shown, the small flange (5) is connected to the large flange (4) by welding.

[0031] In this preferred embodiment, in order to ensure the firmness and good sealing between the small flange (5) and the large flange (4) and to achieve ultra-high vacuum, welding technology is used to connect the two.

[0032] In a preferred embodiment, Figure 1-Figure 3 As shown, the large flange (4) is a CF100 flange, and the small flange (5) is a CF16 flange; a circumferential welding end face is provided on the large flange (4); and the circumferential welding end face is welded to the GM refrigeration expander (1).

[0033] In this preferred embodiment, the existing refrigerator, the expansion machine and the vacuum chamber or the dewar are sealed by an O-ring, and the vacuum can only reach 10-8mbar at best, which cannot be used in an ultra-high vacuum (P<2x10-10 mbar) environment. The CF type flange has good sealing performance and can be used in an ultra-high vacuum environment. Therefore, the GM refrigeration expansion machine (1) and the cold head are connected using a CF type flange, and the GM refrigeration expansion machine (1) and the adapter flange are sealed using a CF-shaped knife edge seal to improve the sealing between the two.

[0034] In a preferred embodiment, Figure 1-Figure 3 As shown, the cold head includes a primary cold head (6) and a secondary cold head (7).

[0035] In this preferred embodiment, the primary cold head (6) and the secondary cold head (7) are respectively suitable for temperature requirements in different situations. If a lower temperature is required, the sample is placed at the secondary cold head (7). If a relatively higher temperature is required, the sample is placed at the primary cold head (6).

[0036] In a preferred embodiment, Figure 1-Figure 3 As shown, the additional device setting hole is located at the connection between the first-stage cold head (6) and the second-stage cold head (7).

[0037] In this preferred embodiment, in the conventional product, in order to ensure the contact area and increase the cooling effect, a cold screen having a diameter much larger than that of the first-level cold head (6) and the second-level cold head (7) is attached to the first-level cold head (6) and the second-level cold head (7), resulting in a larger space required for the first-level cold head (6) and the second-level cold head (7) during movement, and the movement cannot be completed in a small space. In the present product, a compact structural design is adopted between the first-level cold head (6) and the second-level cold head (7), the cold screen attached to the first-level cold head (6) and the second-level cold head (7) is omitted, and the additional device setting hole originally provided on the cold screen is provided at the connection between the first-level cold head (6) and the second-level cold head (7), thereby reducing the required space.

[0038] In a preferred embodiment, Figure 4 , Figure 5 As shown, a wiring groove (8) is provided at the connection; the communication line extends downward through the wiring groove (8).

[0039] In this preferred embodiment, the communication line extends downward along the primary cold head (6) into the wiring groove (8), and then extends downward along the wiring groove (8) from the connection between the primary cold head (6) and the secondary cold head (7) close to the secondary cold head (7). Through the provision of the wiring groove (8), the communication lines can be concentrated and organized.

[0040] It should be pointed out that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A compact GM refrigerator for ultra-high vacuum, comprising a GM refrigeration expander, an adapter flange, and a cold head, wherein one side of the adapter flange is connected to the GM refrigeration expander, and the other side is connected to the cold head, the GM refrigeration expander is provided with a gas inlet and a gas outlet, and the cold head comprises a primary cold head and a secondary cold head, characterized in that: The adapter flange includes a large flange and a small flange; the small flange is connected to the large flange; a flange pipe is arranged on the small flange; the number of the small flanges is two or more; A communication line and a rotating machine are installed in the flange pipeline; the communication line is connected to a sensor in a vacuum environment; the rotating machine is connected to a moving part arranged in a vacuum environment; the communication line is a multi-core electrical feedthrough for vacuum, and the rotating machine adopts a bellows transmission.

2. A compact ultra-high vacuum GM refrigerator according to claim 1, characterized in that: The small flange is connected to the large flange by welding.

3. A compact ultra-high vacuum GM refrigerator according to claim 2, characterized in that: The large flange is provided with a circumferential welding end face; the circumferential welding end face is connected to the GM refrigeration expander by welding.

4. A compact ultra-high vacuum GM refrigerator according to claim 3, characterized in that: A CF type knife edge seal is provided between the circumferential welding end surface and the GM refrigeration expander.

5. A compact ultra-high vacuum GM refrigerator according to claim 1, characterized in that: The additional device setting hole is located at the connection between the first-level cold head and the second-level cold head.

6. A compact ultra-high vacuum GM refrigerator according to claim 5, characterized in that: The connection is provided with a wiring groove; the communication line extends downward through the wiring groove.

7. A compact ultra-high vacuum GM refrigerator according to any one of claims 1 to 6, characterized in that: The large flange is a CF100 flange, and the small flange is a CF16 flange.

8. A compact ultra-high vacuum GM refrigerator according to any one of claims 1 to 6, characterized in that: The gas inlet and the gas outlet face upward.

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