Gas distribution valve and cryogenic refrigerator

Abstract

The application provides a gas distribution valve applied to a low-temperature refrigerator to control helium charging and discharging, comprising a valve shell, a gas distribution valve, an eccentric driving assembly, an inlet control assembly and a first elastic member. The valve shell is internally provided with a mounting hole in communication with a high-pressure helium inlet channel, an expansion cavity channel of the low-temperature refrigerator and a low-pressure helium exhaust channel, the gas distribution valve is in clearance sealing cooperation with the mounting hole and is configured to slide along the axial direction of the mounting hole to control the on-off of helium between the high-pressure helium inlet channel, the expansion cavity channel and the low-pressure helium exhaust channel, the eccentric driving assembly is configured to provide power for the sliding of the gas distribution valve to control the on-off of helium between the high-pressure helium inlet channel and the expansion cavity channel, and the two ends of the first elastic member are respectively in abutment with the gas distribution valve and the inner wall of the valve shell to reset the gas valve after sliding and guarantee the stable timing of gas distribution.

Description

Technical Field

[0001] This application relates to the field of cryogenic vacuum technology, and more specifically, to a gas distribution valve and a cryogenic refrigerator. Background Technology

[0002] In the field of cryogenic vacuum, GM cryogenic refrigerators, as the core cold source of cryogenic pumps, are widely used in scenarios requiring high vacuum environments. They supply high and low-pressure helium through a helium compressor, utilizing the periodic expansion of high-pressure helium to generate a cooling effect by converting it into low-pressure helium, thus achieving temperatures below 10K. However, GM refrigerators require a gas distribution valve to control the helium filling and discharging to achieve precise matching between helium pressure and expansion chamber volume. Existing technologies mostly employ planar rotary valve structures, which, while accurate in gas distribution, suffer from rapid wear, expensive materials, and insufficient sealing reliability, making it prone to gas leakage from the high-pressure chamber to the low-pressure chamber, thus failing to meet the long-term stable operation requirements of the refrigerator. Therefore, developing a gas distribution valve that is reliably sealed, has low wear, is cost-effective, and can precisely adjust the gas distribution sequence, and a cryogenic refrigerator using this valve, has become a key problem urgently needing to be solved in the current cryogenic vacuum technology field. Summary of the Invention

[0003] The purpose of this application is to address the technical problems in related technologies by providing a gas distribution valve and a cryogenic refrigerator. The specific solution is as follows:

[0004] A first aspect of this application provides a gas distribution valve applied to a cryogenic refrigerator to control the charging and discharging of helium, comprising: a valve housing having an internal mounting hole communicating with a high-pressure helium inlet channel, an expansion chamber channel of the cryogenic refrigerator, and a low-pressure helium exhaust channel; a gas distribution valve adapted to be embedded in the mounting hole and forming a clearance-sealed fit with the mounting hole, configured to slide axially along the mounting hole to control the flow of helium between the high-pressure inlet channel, the expansion chamber channel, and the low-pressure exhaust channel; and an eccentric drive assembly including a motor and an eccentric... The eccentric disc is sleeved on the rotating shaft of the motor, and the gas distribution bearing is rotatably mounted on the eccentric disc. The outer circumferential surface of the gas distribution bearing is in contact with the top surface of the gas distribution valve. The motor is configured to drive the eccentric disc to rotate, thereby converting the rotational motion of the eccentric disc into linear sliding of the gas distribution valve, thus providing power for the sliding of the gas distribution valve. An intake control assembly is disposed inside the mounting hole and at least partially abuts against the gas distribution valve. It is configured to move under the drive of the gas distribution valve to control the flow of helium in the high-pressure intake channel and the expansion chamber channel.

[0005] The first elastic element has one end fixed to the inner wall of the valve housing and the other end fixed to the side wall of the gas distribution valve. It is configured to drive the gas distribution valve to slide and then reset, so as to ensure the stability of the gas distribution timing.

[0006] In some embodiments, the air intake control component further includes: an air intake valve body, which is fixedly disposed inside the mounting hole, and the air intake valve body is provided with an airflow channel, configured to connect the air intake channel with the expansion chamber channel to allow the helium gas to flow.

[0007] A valve stem extends through the intake valve body, with one end adjacent to the intake passage serving as the intake sealing end and the other end serving as the push end. The push end abuts against the distribution valve and is configured to, under the push of the distribution valve, control the separation or contact between the intake sealing end and the airflow passage, thereby controlling the flow of external gas.

[0008] In some embodiments, the gas distribution valve further includes a second elastic element disposed between one end of the gas distribution valve adjacent to the high-pressure air intake channel and the inner wall of the mounting hole, configured to maintain the coaxiality of the gas distribution valve and the mounting hole and assist the gas distribution valve in resetting.

[0009] In some embodiments, the valve stem further includes: a protrusion integrally formed on the end face of the air intake sealing end and extending along the axial direction of the valve stem; and a third elastic member sleeved on the protrusion, with both ends abutting against the end face of the air intake sealing end and the inner wall of the valve housing, respectively, configured to assist the valve stem in resetting so that the air intake sealing end blocks the airflow passage.

[0010] In some embodiments, the eccentric drive assembly further includes: a drive bearing rotatably mounted on the eccentric disk, the drive bearing being connected to the piston drive rod of the cryogenic refrigerator, configured to drive the drive rod to reciprocate as the eccentric disk rotates, synchronously driving the piston assembly of the cryogenic refrigerator to change the volume of the expansion chamber of the cryogenic refrigerator.

[0011] In some embodiments, the gas distribution valve further includes: a first sealing ring, embedded in the annular gap between the valve stem and the inner wall of the valve housing inlet end, configured to prevent high-pressure helium from leaking from the gap between the valve stem and the valve housing; and a second sealing ring, embedded in the annular gap between the gas distribution valve and the inner wall of the cylindrical mounting hole of the valve housing, configured to prevent high-pressure helium from leaking from the gap between the gas distribution valve and the mounting hole to the low-pressure side.

[0012] In some embodiments, the gas distribution valve is made of hardened tool steel and its outer surface is coated with polytetrafluoroethylene low-friction polymer material.

[0013] A second aspect of this application provides a cryogenic refrigerator, comprising: a gas distribution valve provided in the first aspect of this application, and further comprising: a refrigerator cylinder, a refrigerator housing, and a piston assembly; one end of the refrigerator housing is sealed to one end of the refrigerator cylinder, and the other end of the refrigerator housing is sealed to the outer casing of the motor; the refrigerator cylinder, the refrigerator housing, and the piston assembly together enclose a sealed high-pressure cavity, wherein the gas distribution valve is sealed to the high-pressure cavity through an expansion cavity channel, and is configured to control the entry of high-pressure helium into the high-pressure cavity and the discharge of low-pressure helium from the high-pressure cavity.

[0014] In some embodiments, the cryogenic refrigerator further includes: a piston assembly disposed inside the refrigerator cylinder, including a primary piston and a secondary piston, the primary piston and the secondary piston being coaxially arranged; the primary piston and the inner wall of the refrigerator cylinder enclose a primary cold cavity, and the secondary piston and the inner wall of the refrigerator cylinder enclose a secondary cold cavity, wherein the piston assembly further includes a piston drive rod configured to move along the axial direction of the refrigerator cylinder to change the volume of the primary cold cavity and the secondary cold cavity.

[0015] In some embodiments, the cryogenic refrigerator further includes a helium compressor and a helium pipeline; the high-pressure output end of the helium compressor is sealed to the high-pressure chamber of the refrigerator through the helium pipeline, and the low-pressure input end of the helium compressor is sealed to the low-pressure exhaust end of the gas distribution valve through the helium pipeline, forming a closed helium circulation loop.

[0016] Compared with related technologies, the above-described solutions of this application have at least the following beneficial effects:

[0017] The gas distribution valve and cryogenic refrigerator provided in this application can reliably prevent high-pressure helium from leaking into the low-pressure side. The eccentric drive component stably converts motion into power for the gas distribution valve, and the first elastic element ensures accurate valve reset, avoiding gas distribution sequence disorder. The cryogenic refrigerator uses the gas distribution valve for precise gas distribution, combined with a two-stage piston and cold chamber design, and a closed-loop helium circulation system to ensure that the helium filling and discharging matches the expansion chamber volume change, meeting the cryogenic pump's cold source requirements and ensuring the acquisition of a high vacuum environment.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0020] Figure 1 This is a schematic diagram of the structure of a gas distribution valve according to an exemplary embodiment.

[0021] Figure 2 This is a flowchart illustrating the control principle of a gas distribution valve according to an exemplary embodiment.

[0022] Figure 3 This is a schematic diagram of the structure of an eccentric drive component according to an exemplary embodiment.

[0023] Figure 4 This is a schematic diagram of the structure of an intake control assembly according to an exemplary embodiment.

[0024] Figure 5 This is a partial structural schematic diagram of a gas distribution valve according to an exemplary embodiment.

[0025] Figure 6 This is a partial structural schematic diagram of a cryogenic refrigeration machine according to an exemplary embodiment.

[0026] Figure 7 This is a schematic diagram illustrating the working principle of a gas distribution valve according to an exemplary embodiment.

[0027] Figure 8 This is a schematic diagram illustrating the working principle of a gas distribution valve according to an exemplary embodiment.

[0028] Figure label:

[0029] Valve housing 100, mounting hole 101, high-pressure air inlet channel 102;

[0030] Air distribution valve 200, spring groove 201, air distribution groove 202, top surface 210;

[0031] Eccentric drive assembly 300, motor 310, motor rotating shaft 311, eccentric disk 320, gas distribution bearing 330, gas distribution bearing central shaft 331, drive bearing 340, drive bearing central shaft 341;

[0032] Intake control assembly 400, intake valve body 410, intake passage 411, valve stem 420, intake sealing end 421, push end 422, protrusion 423, first sealing ring 431, second sealing ring 432;

[0033] First elastic element 510, second elastic element 520, third elastic element 530;

[0034] The refrigerator housing 610, piston assembly 620, first-stage piston 621, second-stage piston 622, expansion chamber 630, first-stage cold chamber 631, second-stage cold chamber 632, drive rod 640, and expansion chamber channel 650. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. “Multiple” generally includes at least two, and other quantifiers are similar.

[0037] It should be understood that although the terms "first," "second," "third," etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the described objects. For example, "first" may also be referred to as "second," and similarly, "second" may also be referred to as "first," without departing from the scope of the embodiments of this application. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] It should be understood that the term "and / or" as used herein is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. The singular forms "a," "the," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0039] It is further understood that the terms “center,” “longitudinal,” “lateral,” “front,” “rear,” “up,” “down,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0040] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0042] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0043] The optional embodiments of this application are described in detail below with reference to the accompanying drawings.

[0044] This application provides a gas distribution valve, which is applied in a cryogenic refrigerator to control the charging and discharging of helium. Figure 1 As shown, the gas distribution valve includes at least a valve body 100, a gas distribution valve 200, an eccentric drive assembly 300, and an intake control assembly 400. The components work together to achieve precise gas distribution.

[0045] In some embodiments, the valve housing 100 is provided with a mounting hole 101, which may be a cylindrical mounting hole 101, providing a mounting carrier for other components of the gas distribution valve. The mounting hole 101 is connected to the high-pressure inlet channel 102 of external helium, the expansion chamber channel 650 of the refrigerator, and the low-pressure exhaust channel, respectively, so that external helium can enter the refrigerator. Specifically, the high-pressure inlet channel 102 is connected to the high-pressure output end of the external helium compressor, responsible for introducing high-pressure helium of 2-2.5MPa into the valve housing 100; the expansion chamber channel 650 is connected to the expansion chamber 630 of the cryogenic refrigerator, ensuring that helium can enter the expansion chamber 630 to participate in refrigeration; the low-pressure exhaust channel is connected to the low-pressure input end of the helium compressor, used to export low-pressure helium of 0.4-0.8MPa after expansion and return it. The high-pressure inlet channel 102 of external helium, the expansion chamber channel 650 of the refrigerator, and the low-pressure exhaust channel form a complete helium flow loop through the mounting hole 101.

[0046] In some embodiments, such as Figure 2 As shown, the gas distribution valve 200 is an actuator that controls the flow of helium. To fit the cylindrical mounting hole 101, the gas distribution valve 200 can be a cylindrical structural component adapted to the structure of the cylindrical mounting hole 101. At least a portion of the gas distribution valve 200 is embedded in the mounting hole 101 and forms a gap seal with the inner wall of the mounting hole 101, effectively preventing gas leakage between the high-pressure intake channel 102 and the low-pressure exhaust channel. The gas distribution valve 200 is configured to slide axially along the cylindrical hole, controlling the on / off state between the high-pressure intake channel 102, the expansion chamber channel 650, and the low-pressure exhaust channel, further realizing the control of helium filling and releasing.

[0047] In some embodiments, the gas distribution valve 200 is provided with a spring groove 201 at one end near the high-pressure air intake channel 102. The spring groove 201 is used to assemble an elastic element so that the gas distribution valve 200 moves within the mounting hole 101 and then achieves coaxial reset under the action of the elastic element. The other end of the gas distribution valve 200 is provided with a top surface 210, which is adapted to contact an external pushing structure so that the gas distribution valve 200 moves axially along the mounting hole 101 under external pushing.

[0048] In some embodiments, such as Figure 1 , Figure 2As shown, in the circumferential direction of the gas distribution valve 200, at least part of the outer wall of the gas distribution valve 200 is recessed inward to form a gas distribution groove 202. In response to the axial movement of the gas distribution valve 200 along the mounting hole 101, the gas distribution groove 202 can selectively communicate with the expansion chamber channel 650 and the low-pressure exhaust channel of the refrigerator, for exporting the expanded low-pressure helium gas backflow, so that the high-pressure intake channel 102 of the external helium gas, the expansion chamber channel 650 of the refrigerator and the low-pressure exhaust channel form a complete helium gas flow loop through the mounting hole 101.

[0049] In some embodiments, the air distribution groove 202 is an annular or strip-shaped groove formed on the outer circumferential surface of the air distribution valve 200, configured to control the connection or disconnection between the low-pressure exhaust passage and the expansion chamber passage 650. When the air distribution valve 200 slides axially along the mounting hole, the air distribution groove 202 can move synchronously with the air distribution valve 200, thereby forming an aligned or offset position with the openings of the low-pressure exhaust passage and the expansion chamber passage 650 on the inner wall of the mounting hole.

[0050] When the gas distribution valve 200 slides to the aligned position, and the two ends of the gas distribution channel 202 are exactly aligned with the expansion chamber channel 650 and the low-pressure exhaust channel respectively, the low-pressure helium gas that has expanded in the expansion chamber 630 of the cryogenic refrigerator can enter the gas distribution channel 202 through the expansion chamber channel 650, then flow through the gas distribution channel 202 to the low-pressure exhaust channel, and finally flow back to the helium compressor to complete the exhaust process. When the gas distribution valve 200 slides to the misaligned position, and the gas distribution channel 202 is misaligned with one of the channel openings, for example, only aligned with the expansion chamber channel 650 and not aligned with the low-pressure exhaust channel, the solid part of the gas distribution valve 200 will block the opening of the low-pressure exhaust channel, and the helium gas cannot flow through the gas distribution channel 202, and the exhaust process will stop immediately.

[0051] In some embodiments, to improve rigidity, the valve 200 is made of hardened tool steel and its outer surface is coated with polytetrafluoroethylene low-friction polymer material. The hardened tool steel enhances wear resistance, and the coating of polytetrafluoroethylene low-friction polymer material can effectively reduce the frictional resistance when the valve 200 slides, ensuring the smoothness of the valve 200 sliding along the mounting hole 101 axially.

[0052] In some embodiments, the low-pressure exhaust passage is disposed on the valve housing 100. One end of the low-pressure exhaust passage communicates with the cylindrical mounting hole 101 inside the valve housing 100, and the other end is connected to the low-pressure input terminal of the helium compressor. The gas distribution valve 200 controls the opening and closing of the low-pressure exhaust passage and the expansion chamber passage 650 by changing the sliding position within the mounting hole 101. When the gas distribution valve 200 slides to the left to a specific position under the drive of the eccentric drive assembly 300, the expansion chamber passage 650 communicates with the low-pressure exhaust passage. At this time, the low-pressure helium gas expanded in the expansion chamber 630 can enter the mounting hole 101 through the expansion chamber passage 650 and then flow back to the helium compressor through the low-pressure exhaust passage. When the gas distribution valve 200 slides to the right, the expansion chamber passage 650 is disconnected from the low-pressure exhaust passage, and exhaust stops. Meanwhile, the gap between the gas distribution valve 200 and the mounting hole 101 is sealed to prevent high-pressure helium from leaking from the gap between the gas distribution valve 200 and the mounting hole 101 into the low-pressure exhaust channel, thus ensuring the sealing of the exhaust process and the stability of the closed-loop helium circulation.

[0053] In some embodiments, such as Figure 3 As shown, the eccentric drive assembly 300 is configured to provide power for the movement of the air distribution valve 200. The eccentric drive assembly 300 mainly includes a motor 310, an eccentric disk 320, an air distribution bearing 330, and a drive bearing 340. The eccentric disk 320 is sleeved on the rotating shaft of the motor 310. Both the air distribution bearing 330 and the drive bearing 340 are rotatably mounted on the eccentric disk 320, and the outer peripheral surface of the air distribution bearing 330 is in close contact with the top surface 210 of the air distribution valve 200.

[0054] In some embodiments, when the motor 310 is started, the motor 310 will drive the eccentric disk 320 to make a circular motion around the rotation axis, and the valve bearing 330 mounted on the eccentric disk 320 will make a circular motion synchronously with the eccentric disk 320. Since the valve bearing 330 is in contact with the top surface 210 of the valve 200, the radial displacement of the valve bearing 330's circular motion will be converted into the linear sliding of the valve 200 along the axial direction of the mounting hole 101.

[0055] In some embodiments, such as Figure 4 As shown, the gas distribution valve also includes an intake control component 400, which includes an intake valve body 410 and a valve stem 420, used to control the opening and closing of the high-pressure intake channel 102 and the expansion chamber channel 650.

[0056] The intake valve body 410 is made of polymer material and is fixed inside the mounting hole 101 of the valve shell 100. An airflow channel is provided inside the intake valve body 410. The airflow channel is directly connected to the high-pressure intake channel 102 and the expansion chamber channel 650, providing a flow path for high-pressure helium.

[0057] The valve stem 420 penetrates the intake valve body 410 and can move axially within the intake valve body 410. One end of the valve stem 420 adjacent to the high-pressure intake channel 102 is an intake sealing end 421, which cooperates with the intake valve body 410 to form a mechanical seal; the other end of the valve stem 420 is a push end 422, which maintains contact with the distribution valve 200. In response to the sliding of the distribution valve 200, the distribution valve 200 synchronously pushes the push end 422 of the valve stem 420, causing the intake sealing end 421 to separate from or fit against the airflow channel of the intake valve body 410, thereby opening or blocking the airflow channel and precisely controlling the entry of high-pressure helium into the expansion chamber 630.

[0058] In some embodiments, to ensure the accurate reset of the valve 200 and valve stem 420, the valve further includes a first elastic element 510. One end of the first elastic element 510 is fixed to the inner wall of the valve housing 100, and the other end is fixed in the valve distribution groove 202 of the valve 200. It is arranged along the sliding direction of the valve 200 and is fixed by welding or snap-fit. It can generate a reset elastic force after the valve 200 slides, so that the valve 200 accurately returns to its initial position, avoiding the problem of valve timing disorder caused by the inability of the valve 200 to reset.

[0059] In some embodiments, to ensure the accurate reset of the valve distribution valve 200 and the valve stem 420, the valve distribution valve further includes a second elastic element 520. The second elastic element 520 is disposed at the end of the valve distribution valve 200 away from the valve distribution bearing 330 and is coaxially arranged with the valve distribution valve 200. One end of the second elastic element 520 is fixedly connected to the bottom inner wall of the valve housing 100, and the other end is fixedly connected to the end of the valve distribution valve 200. It is configured to maintain the coaxiality of the valve distribution valve 200 when sliding, to prevent the valve distribution valve 200 from shifting and affecting the sealing and on / off control, and at the same time assist the valve distribution valve 200 in resetting.

[0060] The second elastic element 520 effectively prevents the air distribution valve 200 from radially shifting during sliding, ensuring that the gap seal between the air distribution valve 200 and the mounting hole 101 remains uniform, avoiding sealing failure and gas leakage caused by shift. At the same time, its auxiliary reset function works in conjunction with the first elastic element 510 to further improve the accuracy and timeliness of the reset of the air distribution valve 200, providing double protection for the precise control of the air distribution sequence.

[0061] In some embodiments, the valve stem 420 further includes a protrusion 423 and a third elastic element 530. The protrusion 423 is integrally formed on the end face of the air intake sealing end 421 and extends axially along the valve stem 420. The third elastic element 530 can be a small spring, sleeved on the protrusion 423, and its two ends abut against the end face of the air intake sealing end 421 and the inner wall of the valve housing 100, respectively. After the valve stem 420 moves, the third elastic element 530 is compressed. The valve stem 420 is configured to generate a reset spring force to assist the valve stem 420 in resetting after being pushed by the air distribution valve 200.

[0062] The reset function of the third elastic element 530 allows the valve stem 420 to quickly return to the position of blocking the airflow passage after the thrust of the air distribution valve 200 disappears. This ensures that the high-pressure air intake passage 102 can be closed in time when air intake is not required, avoiding unnecessary leakage of high-pressure helium. At the same time, the protrusion 423 provides a stable installation position for the third elastic element 530, preventing the third elastic element 530 from shifting during compression. This ensures the stable operation of the reset function, further enhances the reliability of the mechanical seal at the air intake end, and effectively isolates gas leakage caused by poor sealing.

[0063] In some embodiments, the gas distribution valve of this application employs a mechanical seal structure at the inlet end, where the valve stem 420 and the inlet valve body 410 cooperate to achieve a basic seal. This structure is simple in design and can achieve a basic seal without complex components. When the valve is in the closed state, the pressure of the external high-pressure helium gas, together with the elastic force of the third elastic element 530, pushes the inlet sealing end 421 of the valve stem 420 tightly against the inlet valve body 410. The combined action of the external helium gas pressure and the third elastic element 530 strengthens the seal, effectively preventing high-pressure helium gas from leaking from the inlet end and ensuring a stable and reliable sealing effect.

[0064] In some embodiments, such as Figure 3 , Figure 5 As shown, the eccentric drive assembly 300 also includes a drive bearing 340, which is rotatably mounted on the eccentric disk 320 and hinged to one end of the piston drive rod 640 of the cryogenic refrigerator. The other end of the piston drive rod 640 is connected to the piston assembly 620 of the refrigerator. The drive bearing 340 rotates with the eccentric disk 320, driving the piston drive rod 640 to reciprocate, and synchronously driving the piston assembly 620 to move to change the volume of the expansion chamber 630 of the refrigerator.

[0065] Specifically, the connection method between the drive bearing 340 and the eccentric disk 320 is the same as the connection method between the valve bearing 330 and the eccentric disk 320, allowing rotation around its own axis. The piston drive rod 640 is connected to the drive bearing 340 via a hinge shaft, ensuring that the rotation of the drive bearing 340 can drive the piston drive rod 640 to swing, thereby converting it into the reciprocating motion of the piston assembly 620. For example, Figure 5 As shown, the end of the drive rod 640 that is hinged to the drive bearing 340 can be a Chinese character-shaped frame structure.

[0066] The drive bearing 340 enables the eccentric drive assembly 300 to synchronously drive the gas distribution valve 200 and the piston assembly 620, ensuring precise coordination between the sliding of the gas distribution valve 200 and the reciprocating motion of the piston assembly 620. This ensures that the gas distribution timing and the volume change of the expansion chamber 630 are precisely matched, avoiding the problem of reduced refrigeration efficiency caused by the asynchronous movement of the gas distribution valve 200 and the piston assembly 620.

[0067] In some embodiments, such as Figure 3 , Figure 5 , Figure 6 As shown, the distance between the valve bearing center shaft 331 of the valve bearing 330 and the motor rotation shaft 311 of the motor 310 is L1, and the maximum sliding stroke of the valve 200 is 2L1. With this structural design, the eccentric drive component 300 can stably transmit power, providing a guarantee for the precise control of the valve timing and avoiding inaccurate valve timing due to unstable power.

[0068] In some embodiments, the distance between the drive bearing central shaft 341 and the motor rotating shaft 311 is L2, making the maximum reciprocating stroke of the piston assembly 620 2L2. When the eccentric disk 320 rotates, the drive bearing 340 drives the piston drive rod 640 to reciprocate, thereby driving the piston assembly 620 to move and changing the volume of the refrigeration unit expansion chamber 630. This design achieves synchronization between the sliding of the gas distribution valve 200 and the movement of the piston assembly 620, ensuring precise matching between the gas distribution sequence and the volume change of the expansion chamber 630, and avoiding a decrease in refrigeration efficiency due to asynchrony between the two.

[0069] In some embodiments, to further enhance the sealing effect, the gas distribution valve is also provided with a first sealing ring 431 and a second sealing ring 432. At least one annular groove is formed on the intake valve body 410, and the first sealing ring 431 and the second sealing ring 432 are respectively embedded in the annular groove, enhancing the sealing effect between the intake valve body 410 and the valve housing 100 and preventing high-pressure helium gas from leaking from the gap between the intake valve body 410 and the valve housing 100. The double sealing of the first sealing ring 431 and the second sealing ring 432 further ensures the sealing reliability of the gas distribution valve.

[0070] In some embodiments, a sealing ring may also be provided in the annular groove of the gas distribution valve 200 and the inner wall of the mounting hole 101 to enhance the gap sealing effect between the gas distribution valve 200 and the mounting hole 101, prevent high-pressure helium from leaking into the low-pressure exhaust channel, and improve the sealing reliability of the exhaust end.

[0071] The second aspect of this application provides a cryogenic refrigerator, which includes the gas distribution valve described in the first aspect of this application, and further includes a refrigerator cylinder, a refrigerator housing 610, and a piston assembly 620.

[0072] like Figure 6 As shown, one end of the refrigerator housing 610 is sealed to one end of the refrigerator cylinder, and the other end of the refrigerator housing 610 is sealed to the housing of the motor 310 of the gas distribution valve. The refrigerator cylinder, the refrigerator housing 610 and the piston assembly 620 together form a closed high-pressure cavity, which is configured to provide a closed space for helium expansion and refrigeration.

[0073] In some embodiments, the piston assembly 620 is disposed inside the cylinder of the refrigerator. The piston assembly 620 includes a primary piston 621 and a secondary piston 622. The primary piston 621 is sleeved on the outside of the secondary piston 622 and is coaxially arranged with the secondary piston 622, and together they constitute the expansion chamber 630 of the refrigerator.

[0074] The first-stage piston 621 and the inner wall of the refrigerator cylinder form a first-stage cold cavity 631, and the second-stage piston 622 and the inner wall of the refrigerator cylinder form a second-stage cold cavity 632. The first-stage cold cavity 631 can cool the cold shield and baffle in the cryogenic pump to 80K or below, and the second-stage cold cavity 632 can cool the cold plate to 10K or below, meeting the high vacuum refrigeration requirements of the cryogenic pump. The design of the two-stage piston and cold cavity realizes two-stage refrigeration.

[0075] In some embodiments, such as Figure 6 As shown, the first-stage piston 621 and the second-stage piston 622 are connected to the piston drive rod 640. With the synchronous reciprocating motion of the drive rod 640, the pipe of the expansion chamber channel 650 of the gas distribution valve is sealed to the inlet of the first-stage cold chamber 631 and the second-stage cold chamber 632, respectively, ensuring that helium can smoothly enter and exit the cold chamber. The cryogenic refrigerator changes the volume of the cold chamber through the reciprocating motion of the piston assembly 620, and, in conjunction with the gas distribution valve, realizes the charging and discharging of helium, completing the refrigeration process.

[0076] In some embodiments, the first-stage piston 621 is filled with stainless steel mesh or copper mesh cold storage material, and the second-stage piston 622 is filled with lead ball low-temperature cold storage medium. The selection of different cold storage materials is adapted to the refrigeration temperature requirements of different cold chambers, improving the cold storage efficiency. The connection design between the gas distribution valve and the cold chamber ensures that the helium charging and discharging can be accurately applied to the cold chamber, providing structural support for the realization of the refrigeration effect.

[0077] In some embodiments, the cryogenic refrigerator also includes a control module, which is electrically connected to the motor 310 and the helium compressor respectively. The control module is configured to drive the helium compressor to provide high-purity helium gas with alternating high and low pressure. It can also adjust the operating frequency of the motor 310, thereby adjusting the sliding frequency of the gas distribution valve 200 and the reciprocating frequency of the piston assembly 620, so as to achieve precise matching between the gas distribution sequence and the volume change of the expansion chamber 630.

[0078] The control module enables adjustable operating parameters of the cryogenic refrigerator, allowing the frequency of motor 310 to be adjusted according to actual refrigeration needs, thereby optimizing the gas distribution sequence and ensuring that the helium charging and discharging and the volume change of expansion chamber 630 are always in optimal matching state, thus improving refrigeration efficiency. At the same time, its drive control of the helium compressor ensures that the high-pressure helium pressure is stable at 2-2.5MPa and the low-pressure helium pressure is stable at 0.4-0.8MPa, providing a guarantee for the stable operation of the refrigeration cycle and further improving the overall performance of the cryogenic refrigerator.

[0079] In some embodiments, such as Figure 7 As shown, the valve bearing 330 drives the valve 200 to move toward the high-pressure intake channel 102. When the valve 200 contacts the valve stem 420, the high-pressure gas fills the space between the airflow channel and the valve stem 420. The valve stem 420 of the intake control assembly 400 is subjected to the elastic force of the third elastic element 530 and the pressure of the high-pressure gas, and it fits together with the intake valve body 410 to form a sealing structure, thus isolating the high-pressure gas and the low-pressure gas.

[0080] In some embodiments, such as Figure 8 As shown, as the valve bearing 330 drives the valve 200 to move further toward the high-pressure intake channel 102, the valve stem 420 separates from the port of the airflow channel under the push of the valve 200, and the high-pressure gas is filled into the expansion chamber 630 of the refrigerator.

[0081] As the valve bearing 330 continues to operate, the valve 200 moves towards the high-pressure intake channel 102 to its maximum value, and the intake channel opens to its maximum extent. Then, as the valve bearing 330 rotates, the valve 200, under the action of the first elastic element 510, begins to move away from the high-pressure intake channel 102. When the valve 200 moves to... Figure 7 When in position, the high-pressure chamber and the low-pressure chamber are connected, and the high pressure in the expansion chamber 630 becomes low pressure.

[0082] The specific structure, working principle, and beneficial effects of the gas distribution valve and cryogenic refrigerator provided in this application embodiment can be referred to the gas distribution valve and cryogenic refrigerator described in any of the above embodiments, and will not be repeated here.

[0083] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems or apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0084] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A gas distribution valve, characterized in that, Used in cryogenic refrigerators to control the filling and releasing of helium, including: The valve housing has an internal mounting hole that is connected to the high-pressure inlet channel of external helium, the expansion chamber channel of the cryogenic refrigerator, and the low-pressure exhaust channel of external helium. A gas distribution valve is adapted to be embedded in the mounting hole and forms a gap sealing fit with the mounting hole. It is configured to slide along the axial direction of the mounting hole to control the flow of helium between the high-pressure intake channel, the expansion chamber channel and the low-pressure exhaust channel. An eccentric drive assembly includes a motor, an eccentric disc, and a valve bearing. The eccentric disc is sleeved on the rotating shaft of the motor, and the valve bearing is rotatably mounted on the eccentric disc. The outer peripheral surface of the valve bearing is in contact with the top surface of the valve. The motor is configured to drive the eccentric disc to rotate, thereby converting the rotational motion of the eccentric disc into linear sliding of the valve, and providing power for the sliding of the valve. An intake control assembly, disposed inside the mounting hole and at least partially abutting against the gas distribution valve, is configured to move under the drive of the gas distribution valve to control the flow of helium in the high-pressure intake channel and the expansion chamber channel; The first elastic element has one end fixed to the inner wall of the valve housing and the other end fixed to the side wall of the gas distribution valve. It is configured to drive the gas distribution valve to slide and then reset, so as to ensure the stability of the gas distribution timing.

2. The gas distribution valve according to claim 1, characterized in that, The intake control assembly also includes: An intake valve body is fixedly installed inside the mounting hole, and an airflow channel is provided inside the intake valve body, configured to connect the intake channel with the expansion chamber channel to allow the helium gas to flow. A valve stem extends through the intake valve body, with one end adjacent to the intake passage serving as the intake sealing end and the other end serving as the push end. The push end abuts against the distribution valve and is configured to control the separation or contact between the intake sealing end and the airflow passage under the push of the distribution valve, thereby controlling the flow of external gas.

3. The gas distribution valve according to claim 1, characterized in that, Also includes: The second elastic element is disposed between one end of the gas distribution valve adjacent to the high-pressure air intake channel and the inner wall of the mounting hole, and is configured to maintain the coaxiality of the gas distribution valve and the mounting hole and assist the gas distribution valve in resetting.

4. The gas distribution valve according to claim 2, characterized in that, The valve stem also includes: The protrusion is integrally formed on the end face of the air intake sealing end and extends along the axial direction of the valve stem; The third elastic element is sleeved on the protrusion, and its two ends abut against the end face of the air inlet sealing end and the inner wall of the valve body, respectively. It is configured to assist the valve stem in resetting so that the air inlet sealing end blocks the airflow passage.

5. The gas distribution valve according to claim 1, characterized in that, The eccentric drive component also includes: A drive bearing is rotatably mounted on an eccentric disk and connected to the piston drive rod of the cryogenic refrigerator. The drive bearing is configured to rotate with the eccentric disk to drive the drive rod to reciprocate, synchronously driving the piston assembly of the cryogenic refrigerator to change the volume of the expansion chamber of the cryogenic refrigerator.

6. The gas distribution valve according to claim 2, characterized in that, Also includes: The first sealing ring is embedded in the annular gap between the valve stem and the inner wall of the valve housing inlet end, and is configured to prevent high-pressure helium gas from leaking from the gap between the valve stem and the valve housing. The second sealing ring is embedded in the annular gap between the gas distribution valve and the inner wall of the cylindrical mounting hole of the valve body, and is configured to prevent high-pressure helium gas from leaking from the gap between the gas distribution valve and the mounting hole to the low-pressure side.

7. The gas distribution valve according to claim 2, characterized in that, The gas distribution valve is made of hardened tool steel and its outer surface is coated with polytetrafluoroethylene low-friction polymer material.

8. A cryogenic refrigerator, characterized in that, Including the gas distribution valve according to any one of claims 1-7, further comprising: The refrigerator comprises a cylinder, a housing, and a piston assembly; one end of the housing is sealed to one end of the cylinder, and the other end of the housing is sealed to the outer casing of the motor. The cylinder, housing, and piston assembly together form a closed, high-pressure chamber. The gas distribution valve is sealed and connected to the high-pressure cavity through the expansion chamber channel, and is configured to control the entry of high-pressure helium into the high-pressure cavity and the discharge of low-pressure helium from the high-pressure cavity.

9. The cryogenic refrigerator according to claim 8, characterized in that, Also includes: A piston assembly, disposed inside the cylinder of the refrigeration unit, includes a primary piston and a secondary piston, wherein the primary piston and the secondary piston are coaxially arranged. The first-stage piston and the inner wall of the refrigerator cylinder form a first-stage cold cavity, and the second-stage piston and the inner wall of the refrigerator cylinder form a second-stage cold cavity. The piston assembly further includes a piston drive rod configured to move axially along the cylinder of the refrigeration unit to change the volume of the primary cold chamber and the secondary cold chamber.

10. The cryogenic refrigerator according to claim 8, characterized in that, Also includes: A helium compressor and a helium pipeline; the high-pressure output end of the helium compressor is sealed to the high-pressure chamber of the refrigerator through the helium pipeline, and the low-pressure input end of the helium compressor is sealed to the low-pressure exhaust end of the gas distribution valve through the helium pipeline, forming a closed helium circulation loop.

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