Needle valve and pulse tube refrigerating system

Abstract

The invention relates to the technical field of pulse tube refrigerating systems, and provides a needle valve and a pulse tube refrigerating system. The needle valve comprises a valve seat and a valve element, the valve seat is provided with a valve port and an outlet, and a first mounting cavity and a second mounting cavity which communicate with each other are formed in the valve seat; the valve element comprises a conical valve element part and an adjusting part which are connected, and the sectional area of the conical valve element part is gradually increased from the direction away from the adjusting part to the direction close to the adjusting part. The conical valve element part is arranged in the first mounting cavity, a first flow channel is formed between the conical valve element part and the inner wall face of the first mounting cavity, the valve port is formed in the end of the first flow channel, and the outlet communicates with the first flow channel; the adjusting part is movably mounted in the second mounting cavity and can drive the conical valve element part to move back and forth along the center line of the valve port so as to adjust the flow of the first flow channel; the outer tangent line of the conical valve element part and the center line of the conical valve element part form a conical face angle A, and A is larger than 0 degree and smaller than 17 degrees. A is larger than 17 degrees and smaller than 90 degrees, and forward direct current is introduced through the needle valve.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pulse tube refrigeration system, and particularly relates to a needle valve and a pulse tube refrigeration system. BACKGROUND

[0002] In the field of liquid helium temperature region (below 4.2 K) refrigeration, two-stage pulse tube refrigerator has become a key technology to replace the traditional G-M refrigerator due to its advantages of no moving parts, small vibration and high reliability. The core of its refrigeration performance is the optimization of the thermodynamic efficiency of the regenerator and the pulse tube, and the efficiency is directly dependent on the phase matching degree between the pressure wave and the mass flow.

[0003] At present, the mainstream technology adopts a phase modulation scheme of a bidirectional gas inlet structure cooperating with a small hole gas reservoir: the mass flow distribution of the cold and hot ends of the pulse tube is dynamically adjusted through the bidirectional gas inlet valve, and the impedance matching is formed by using the resistance and capacitance characteristics of the small hole gas reservoir, so that the phase difference between the pressure wave and the mass flow is optimized. However, the structure forms a closed circulation flow path of “regenerator -> cold end heat exchanger -> pulse tube -> bidirectional valve -> regenerator” in actual operation, resulting in a non-zero time-averaged mass flow (direct current component) in the system.

[0004] The existing direct current regulation technology adopts mechanical regulating valve regulation and relies on dynamic sealing. The fixed geometric structure regulation (such as a pre-set flow resistance hole) cannot adapt to the variable working condition requirement and has insufficient regulation accuracy; the passive impedance element (such as a capillary tube) relies on empirical design and is difficult to achieve accurate compensation in a wide temperature range. SUMMARY

[0005] The present application provides a needle valve and a pulse tube refrigeration system to solve the problems of low precision and great processing difficulty in the prior art direct current regulation technology.

[0006] The present application provides a needle valve, comprising: a valve seat provided with a valve port and an outlet, the valve seat is internally structured with a first installation cavity and a second installation cavity in communication with each other; a valve core comprising a connected tapered valve core part and an adjusting part, the cross-sectional area of the tapered valve core part gradually increases from the direction away from the adjusting part to the direction close to the adjusting part; the tapered valve core part is arranged in the first installation cavity, a first flow channel is formed between the tapered valve core part and the inner wall surface of the first installation cavity, the valve port is arranged at the end of the first flow channel, and the outlet is in communication with the first flow channel; the adjusting part is movably installed in the second installation cavity, the adjusting part can drive the tapered valve core part to move back and forth along the center line of the valve port to adjust the flow of the first flow channel; the tangent line of the tapered valve core part and its center line forms a conical surface angle A, 0°<A<17°, the needle valve introduces negative direct current; 17°<A<90°, the needle valve introduces positive direct current.

[0007] According to a needle valve provided by the present invention, the conical valve core includes a conical valve core and a frustum-shaped valve core.

[0008] According to a needle valve provided by the present invention, there are multiple conical valve cores connected in sequence, and the cone angle of the conical valve cores gradually increases along the direction from the conical valve core to the adjusting part.

[0009] According to a needle valve provided by the present invention, the valve core further includes a cylindrical valve core portion disposed between the conical valve core portion and the adjusting portion. The cross-sectional area of ​​the end of the conical valve core portion near the cylindrical valve core portion is the same as the cross-sectional area of ​​the cylindrical valve core portion. The cross-sectional area of ​​the cylindrical valve core portion is smaller than the cross-sectional area of ​​the adjusting portion. The cylindrical valve core portion is disposed within a first mounting cavity, and a second flow channel is formed between the outer wall surface of the cylindrical valve core portion and the inner wall surface of the first mounting cavity. The outlet communicates with the second flow channel.

[0010] According to a needle valve provided by the present invention, the valve core further includes a first sealing portion, which is disposed between the cylindrical valve core portion and the adjusting portion and located in the second mounting cavity. The cross-sectional area of ​​the first sealing portion is larger than the cross-sectional area of ​​the first mounting cavity to seal the second flow channel.

[0011] According to a needle valve provided by the present invention, a third flow channel is formed between the outer wall surface of the first sealing part and the inner wall surface of the second mounting cavity, and the outlet is connected to the third flow channel; the cross-sectional area of ​​the adjusting part is larger than the cross-sectional area of ​​the first sealing part, and the outer wall surface of the adjusting part is movably and sealingly connected to the outer wall surface of the second mounting cavity.

[0012] According to a needle valve provided by the present invention, the outer wall surface of the adjusting part is provided with an external thread, and the second mounting cavity is provided with an internal thread, and the adjusting part is threadedly connected to the second mounting cavity.

[0013] According to a needle valve provided by the present invention, the length of the conical valve core is L1, the length of the cylindrical valve core is L2, the length of the external thread is L3, and L3 = L1 + L2.

[0014] According to a needle valve provided by the present invention, the valve seat has a third mounting cavity, which is located on the side of the second mounting cavity away from the first mounting cavity, and the cross-sectional area of ​​the third mounting cavity is larger than that of the second mounting cavity; the valve core further includes a second sealing part, which is located in the third mounting cavity and at the end of the adjusting part away from the conical valve core part; the outer wall surface of the second sealing part has a groove, which forms a receiving cavity with the inner wall surface of the third mounting cavity to embed a sealing element.

[0015] The present invention also provides a pulse tube refrigeration system, including a needle valve as described in any of the above claims, a compressor, and a pulse tube, wherein the valve port of the needle valve is connected to the outlet of the compressor, and the outlet of the needle valve is connected to the pulse tube.

[0016] The needle valve and pulse tube refrigeration system provided by this invention, by installing a conical valve core in a first mounting cavity and an adjusting part in a second mounting cavity, allows the conical valve core to move back and forth along the valve port centerline by moving the adjusting part axially along the second mounting cavity, thereby adjusting the flow rate of the first flow channel. By setting different cone angles to form different levels of needle valves, the evaporation design shifts from "experience-driven" to "data-driven," enabling flexible DC control of different directions and sizes, precise control of system mass flow distribution, effective improvement of overall thermal efficiency, and easy processing. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a front view of the needle valve provided by the present invention.

[0019] Figure 2 This is a cross-sectional view of the needle valve provided by the present invention.

[0020] Figure 3 This is a schematic diagram of the valve core provided by the present invention.

[0021] Figure 4 This is a schematic diagram of the valve seat provided by the present invention.

[0022] Figure 5 This is a cross-sectional view of the valve seat provided by the present invention.

[0023] Figure 6 This is a schematic diagram showing the relationship between the cone angle of the cone-shaped valve core and the direct flow rate provided by the present invention.

[0024] Figure label: 10. Valve seat; 11. Valve port; 12. Outlet; 13. Mounting port; 14. First mounting cavity; 15. Second mounting cavity; 16. Third mounting cavity; 17. First flow channel; 18. Second flow channel; 19. Third flow channel; 20. Valve core; 21. Conical valve core; 22. Cylindrical valve core; 23. Adjustment part; 24. First sealing part; 25. Second sealing part; 251. Groove. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] In the description of the embodiments of the present invention, 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 the embodiments of the present invention based on the specific circumstances.

[0027] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" 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 the embodiments of the present invention 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 embodiments of the present invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0031] The following is combined Figures 1-6 The needle valve and pulse tube refrigeration system of the present invention are described.

[0032] The needle valve provided in this embodiment of the invention includes a valve seat 10 and a valve core 20. The valve seat 10 has a first mounting cavity 14 and a second mounting cavity 15 that are interconnected. The valve core 20 includes a conical valve core portion 21 and an adjusting portion 23 connected together. The cross-sectional area of ​​the conical valve core portion 21 gradually increases from the direction away from the adjusting portion 23 to the direction closer to the adjusting portion 23. The conical valve core portion 21 is disposed within the first mounting cavity 14, forming a first flow channel 17 between the conical valve core portion 21 and the inner wall surface of the first mounting cavity 14. A valve port 11 is disposed at the end of the first flow channel 17, and an outlet 12 communicates with the first flow channel 17. The adjusting portion 23 is movably mounted in the second mounting cavity 15. The adjusting portion 23 can drive the conical valve core portion 21 to move back and forth along the centerline of the valve port 11 to adjust the flow rate of the first flow channel 17. The outer tangent of the conical valve core 21 forms a conical angle A with its own center line. If 0° < A < 17°, the needle valve can introduce negative DC; if 17° < A < 90°, the needle valve can introduce positive DC.

[0033] It should be noted that forward direct current (DC) refers to a truly closed-loop circulation (from a system perspective) formed by the working fluid along the path "regenerator → cold-end heat exchanger → pulse tube → needle valve → regenerator". In this case, the gas flow direction in the first-stage regenerator (40K temperature range) and the second-stage regenerator (liquid nitrogen temperature range) is consistent with the alternating flow direction driven by the pressure wave, resulting in an additional time-averaged heat load within the regenerator packing. Negative DC refers to a counterclockwise closed-loop circulation formed by the working fluid along the path "regenerator → needle valve → pulse tube → cold-end heat exchanger → regenerator". In this case, the DC direction is opposite to the alternating flow direction driven by the pressure wave, which may partially offset the heat load within the regenerator, but it will alter the mixing effect at the cold end of the pulse tube.

[0034] refer to Figure 4 and Figure 5The valve seat 10 has a cylindrical structure. A valve port 11 and a mounting port 13 are respectively provided at both ends of the valve seat 10, and an outlet 12 is located on the side wall of the valve seat 10. The valve seat 10 internally comprises a first mounting cavity 14 and a second mounting cavity 15, which are connected and coaxially arranged. The cross-sectional area of ​​the first mounting cavity 14 is smaller than that of the second mounting cavity 15. The valve port 11 is located at the end of the first mounting cavity 14 furthest from the second mounting cavity 15 and is connected to the first mounting cavity 14. The mounting port 13 is located at the end of the second mounting cavity 15 furthest from the first mounting cavity 14 and is connected to the second mounting cavity 15. The valve port 11 and the mounting port 13 are coaxial.

[0035] The valve core 20 includes a conical valve core portion 21 and an adjusting portion 23, which are connected. The cross-sectional area of ​​the conical valve core portion 21 gradually increases from the direction away from the adjusting portion 23 to the direction closer to the adjusting portion 23. The valve core 20 is mounted inside the valve seat 10 through a mounting port 13. (Reference) Figure 1 and Figure 2 The conical valve core 21 is located within the first mounting cavity 14, and the adjusting part 23 is movably mounted within the second mounting cavity 15 and is sealed to the second mounting cavity 15. Specifically, the cross-sectional area of ​​the conical valve core 21 is smaller than the cross-sectional area of ​​the first mounting cavity 14, and the size of the valve port 11 is larger than the maximum cross-sectional area of ​​the conical valve core 21, meaning the conical valve core 21 can pass through the valve port 11, and there is a gap between the outer wall surface of the conical valve core 21 and the valve port 11 to allow fluid passage. A first flow channel 17 is formed between the outer wall surface of the conical valve core 21 and the outer wall surface of the first mounting cavity 14. The outlet 12 communicates with the first flow channel 17.

[0036] In actual operation, the adjusting part 23 is driven to move back and forth along the axis of the second mounting cavity 15 by manual or mechanical means. The adjusting part 23 drives the conical valve core 21 to move back and forth along the center line of the valve port 11 to adjust the flow rate of the fluid. Specifically, the flow rate of the first flow channel 17 is adjusted by adjusting the position of the conical valve core 21 in the first mounting cavity 14. The fluid enters the first flow channel 17 through the valve port 11 and flows out through the outlet 12. It should be noted that when the adjusting part 23 adjusts the position of the conical valve core 21 in the first mounting cavity 14, the conical valve core 21 can be inserted into the valve port 11 and can move within the first mounting cavity 14.

[0037] In this embodiment of the invention, the cross-sectional area of ​​the conical valve core 21 is variable, and the cross-sectional area of ​​the first flow channel 17 formed is also variable, which can realize a large-span impedance adjustment and meet the system's requirements for a wide range of impedance changes.

[0038] refer to Figure 6The outer tangent of the conical valve core 21 forms a conical angle A with its own centerline. Conical angle A is a key factor determining the direction of direct current (DC). When conical angle A is 17°, the needle valve acts as a first-stage bidirectional valve to achieve DC within the first-stage system, where the DC is approximately zero. When 0° < A < 17°, the needle valve is configured in the second-stage system to introduce the required negative DC. In practical applications, a combination of slightly positive DC in the first stage and stronger negative DC in the second stage can achieve complementary control of the system's DC, thereby optimizing overall refrigeration efficiency. When 17° < A < 90°, the needle valve introduces positive DC, and the DC first increases and then decreases as the conical angle A increases.

[0039] The needle valve provided in this embodiment of the invention, by installing the conical valve core 21 in the first mounting cavity 14 and the adjusting part 23 in the second mounting cavity 15, can drive the conical valve core 21 to move back and forth along the center line of the valve port 11 by moving the adjusting part 23 along the axial direction of the second mounting cavity 15, thereby adjusting the flow rate of the first flow channel 17. By setting different cone angles to form needle valves of different levels, the design of evaporation is shifted from "experience-driven" to "data-driven", which can flexibly realize DC control of different directions and sizes, accurately control the system mass flow distribution, effectively improve the overall thermal efficiency, and is easy to process.

[0040] The present invention regulates DC by setting conical valve cores 21 with different conical angles; the needle valve can be manufactured using standard machining methods. Compared with complex structures such as proportional valves, multi-hole valves, or dual-channel valves, it has low cost, high processing consistency, and is easy to scale up for engineering applications.

[0041] In some embodiments of the present invention, the conical valve core 21 is a cone-shaped valve core, that is, the end away from the adjusting part 23 is a pointed end. In some embodiments of the present invention, the conical valve core 21 is a frustoconical valve core, such as... Figure 3 As shown, both ends of the frustum valve core are flat. The dimensions of the two end faces of the frustum valve core 20 are not limited.

[0042] In some embodiments of the present invention, there are multiple conical valve cores 21 connected in sequence, and the cone angle of the conical valve core 21 gradually increases along the direction from the conical valve core 21 to the adjustment part 23.

[0043] In one specific embodiment, there are two conical valve cores 21, namely a first conical valve core and a second conical valve core. The first conical valve core, the second conical valve core, and the adjusting part 23 are connected in sequence, wherein the conical angle of the first conical valve core is smaller than that of the second conical valve core. In actual use, the corresponding conical valve core 21 can be selected for adjustment as needed to enhance the adjustment accuracy. The number of conical valve cores 21 in this embodiment is not limited to two, but can also be three, four, six, etc.

[0044] In some embodiments of the present invention, the valve core 20 further includes a cylindrical valve core portion 22, which is disposed between the conical valve core portion 21 and the adjusting portion 23. The cross-sectional area of ​​the end of the conical valve core portion 21 near the cylindrical valve core portion 22 is the same as the cross-sectional area of ​​the cylindrical valve core portion 22. The cylindrical valve core portion 22 is disposed within the first mounting cavity 14, and a second flow channel 18 is formed between the outer wall surface of the cylindrical valve core portion 22 and the inner wall surface of the first mounting cavity 14. The outlet 12 communicates with the second flow channel 18.

[0045] refer to Figure 3 The valve core 20 includes a conical valve core portion 21, a cylindrical valve core portion 22, and an adjusting portion 23, which are sequentially connected and coaxial. The cross-sectional area of ​​the conical valve core portion 21 is less than or equal to the cross-sectional area of ​​the cylindrical valve core portion 22, and the cross-sectional area of ​​the cylindrical valve core portion 22 is less than the cross-sectional area of ​​the adjusting portion 23. The valve core 20 is mounted inside the valve seat 10 through the mounting port 13. (Reference) Figure 1 and Figure 2 The conical valve core 21 and the cylindrical valve core 22 are located within the first mounting cavity 14, and the adjusting part 23 is movably mounted within the second mounting cavity 15 and is sealed to the second mounting cavity 15. Specifically, the cross-sectional area of ​​the cylindrical valve core 22 is smaller than that of the first mounting cavity 14, and the cross-sectional area of ​​the conical valve core 21 is also smaller than that of the first mounting cavity 14. The size of the valve port 11 is larger than the cross-sectional area of ​​the cylindrical valve core 22, and the size of the valve port 11 is also larger than that of the conical valve core 21. That is, the conical valve core 21 and the cylindrical valve core 22 can pass through the valve port 11, and there is a gap between the outer wall surface of the conical valve core 21 and the outer wall surface of the cylindrical valve core 22 and the valve port 11 to allow fluid to pass through. A first flow channel 17 is formed between the outer wall surface of the conical valve core 21 and the inner wall surface of the first mounting cavity 14, and a second flow channel 18 is formed between the outer wall surface of the cylindrical valve core 22 and the inner wall surface of the first mounting cavity 14. Outlet 12 is connected to the second flow channel 18.

[0046] In actual operation, the adjusting part 23 is driven to move back and forth along the axis of the second mounting cavity 15 by manual or mechanical means. The adjusting part 23 drives the conical valve core 21 and the cylindrical valve core 22 to move back and forth along the center line of the valve port 11 to adjust the flow rate of the fluid. Specifically, the conical valve core 21 is inserted into the valve port 11, and the position of the conical valve core 21 in the first mounting cavity 14 can be adjusted by the adjusting part 23 to adjust the flow rate in the first flow channel 17 and the second flow channel 18. At this time, the flow rates of the first flow channel 17 and the second flow channel 18 both change. The fluid enters the first flow channel 17 and the second flow channel 18 through the valve port 11 and then flows out through the outlet 12. Figure 2As shown by the middle arrow. When the adjusting part 23 drives the cylindrical valve core 22 to be inserted into the valve port 11, only the second flow channel 18 exists. The length of the cylindrical valve core 22 in the first mounting cavity 14 can be adjusted by the adjusting part 23 to adjust the flow rate in the second flow channel 18. At this time, the fluid enters the second flow channel 18 from the valve port 11 and flows out through the outlet 12.

[0047] It should be noted that when the adjusting part 23 adjusts the position of the conical valve core 21 in the first mounting cavity 14, the conical valve core 21 can be inserted into the valve port 11 and move, or it can move entirely within the first mounting cavity 14. When the conical valve core 21 is fully inserted into the valve port 11, the cylindrical valve core 22 is partially located within the first mounting cavity 14 and partially located outside the valve seat 10.

[0048] The needle valve provided in this embodiment of the invention, by installing a conical valve core 21 and a cylindrical valve core 22 in a first mounting cavity 14, wherein the cross-sectional area of ​​the conical valve core 21 is smaller than that of the cylindrical valve core 22, and an adjusting part 23 is installed in a second mounting cavity 15, the adjusting part 23 moves along the axial direction of the second mounting cavity 15, which can drive the conical valve core 21 and the cylindrical valve core 22 to move back and forth along the central axis of the valve port 11, thereby adjusting the flow rate of the first flow channel 17 and the second flow channel 18. The adjustment speed is fast, the impedance adjustment range is increased, the adjustable range of the flow rate is widened, the response speed of the pulse tube refrigeration system is improved, thereby improving the working efficiency; and no phase adjustment auxiliary device is required, reducing the complexity of the equipment and effectively saving space.

[0049] To improve the sealing effect, in some embodiments of the present invention, the valve core 20 further includes a first sealing part 24, which is disposed between the cylindrical valve core part 22 and the adjusting part 23 and located in the second mounting cavity 15. The cross-sectional area of ​​the first sealing part 24 is larger than the cross-sectional area of ​​the first mounting cavity 14 to seal the second flow channel 18.

[0050] Specifically, the cross-sectional area of ​​the first sealing part 24 is larger than the cross-sectional area of ​​the first mounting cavity 14 and smaller than the cross-sectional area of ​​the second mounting cavity 15. The bottom surface of the second mounting cavity 15 (the side closest to the first mounting cavity 14) forms a stepped surface; that is, the cross-sectional area of ​​the first sealing part 24 is larger than the cross-sectional area of ​​the cylindrical valve core 22. The end of the first sealing part 24 near the first mounting cavity 14 abuts against the stepped surface to seal the second flow channel 18. In one embodiment, the first sealing part 24 is provided with a through hole, and the cylindrical valve core 22 is connected to the end of the first sealing part 24 near the adjusting part 23 through the through hole. The first sealing part 24 is an elastic element. When the adjusting part 23 drives the conical valve core 21 and the cylindrical valve core 22 to move back and forth along the axis of the first mounting cavity 14, the first sealing part 24 undergoes elastic deformation to match its movement. During the movement, the end of the first sealing part 24 near the first mounting cavity 14 abuts against the stepped surface to achieve sealing.

[0051] In some embodiments of the present invention, the outer wall surface of the first sealing portion 24 and the outer wall surface of the second mounting cavity 15 form a third flow channel 19, and the outlet 12 communicates with the third flow channel 19. (See reference) Figure 3 The first flow channel 17, the second flow channel 18, and the third flow channel 19 are connected in sequence. The valve port 11 is connected to the first flow channel 17, and the outlet 12 is connected to the third flow channel 19. The flow direction of the fluid is as follows: Figure 3 As indicated by the middle arrow, the cross-sectional area of ​​the adjusting part 23 is larger than that of the first sealing part 24. The outer wall surface of the adjusting part 23 is movably and sealingly connected to the outer wall surface of the second mounting cavity 15, such as through a threaded connection.

[0052] In one embodiment, the adjusting part 23 adjusts the conical valve core 21 and the cylindrical valve core 22. When the cylindrical valve core 22 is fully located in the first mounting cavity 14, the end stepped surface of the first sealing part 24 abuts against it, thereby sealing the second flow channel 18 and blocking the communication between the valve and the outlet 12. In one embodiment, the first sealing part 24 and the cylindrical valve core 22 are transitionally connected, resulting in a good sealing effect.

[0053] In some embodiments of the present invention, the adjusting part 23 and the second mounting cavity 15 are connected by a rotational seal. For example... Figure 3 As shown, the outer wall surface of the adjusting part 23 is provided with external threads, such as... Figure 5 As shown, the second mounting cavity 15 is provided with an internal thread, and the adjusting part 23 is threadedly connected to the second mounting cavity 15 to achieve a sealed connection, preventing fluid in the third flow channel 19 from flowing out from the inner wall of the adjusting part 23 and the second mounting cavity 15. In actual operation, by rotating the adjusting part 23 to adjust the position of the conical valve core 21 and the cylindrical valve core 22 in the first mounting cavity 14, the cross-sectional area of ​​the first flow channel 17 and the second flow channel 18 can be adjusted, allowing for continuous flow rate adjustment and precise fluid control.

[0054] To improve adjustment accuracy, this invention allows for precise control of the conical valve core 21 and cylindrical valve core 22 by controlling the length of their threads, thereby enhancing adjustment efficiency. Specifically, the length of the conical valve core 21 is L1, the length of the cylindrical valve core 22 is L2, and the external thread length is L3, where L3 = L1 + L2. During actual adjustment, the adjusting part 23 rotates clockwise or counterclockwise, causing the thread length (the thread length being the length in the extending direction of the adjusting part 23) to move within the range of L1. At this time, the conical valve core 21 performs the adjustment function, and when the thread length of the adjusting part 23 moves within the range of L2, the cylindrical valve core 22 performs the adjustment function, thus achieving controllable adjustment. When there are multiple conical valve cores 21, L1 represents the total length of all conical valve cores 21. The adjustment length of the adjusting part 23 can be controlled according to the length of each conical valve core 21 to achieve precise control of the flow rate of each conical valve core 21.

[0055] In one specific embodiment, the length of the conical valve core 21 is 1.5 mm, and the length of the cylindrical valve core 22 is 10 mm. The length of the adjusting part 23 is 11.5 mm. When the thread length of the adjusting part 23 is adjusted within the range of 0-1.5 mm, the conical valve core 21 plays an adjusting role. Due to the large change in cross-sectional area of ​​the conical valve core 21, a large-span impedance adjustment can be achieved, meeting the system's requirements for a wide range of impedance changes. When the thread length of the adjusting part 23 is adjusted within the range of 1.5-11.5 mm, the cylindrical valve core 22 plays an adjusting role. The cylindrical valve core 22 can achieve a small-range impedance fine adjustment, thereby achieving a wider flow regulation range.

[0056] In some embodiments of the present invention, a third mounting cavity 16 is further constructed within the valve seat 10. The third mounting cavity 16 is located on the side of the second mounting cavity 15 away from the first mounting cavity 14. The first mounting cavity 14, the second mounting cavity 15, and the third mounting cavity 16 are sequentially connected and coaxial. The cross-sectional area of ​​the third mounting cavity 16 is larger than the cross-sectional area of ​​the second mounting cavity 15. The mounting port 13 is located on the side of the third mounting cavity 16 away from the second mounting cavity 15.

[0057] The valve core 20 also includes a second sealing part 25, which is disposed in the third mounting cavity 16. The second sealing part 25 is located at the end of the adjusting part 23 away from the conical valve core part 21. The outer wall surface of the second sealing part 25 is in contact with the outer wall surface of the third mounting cavity 16, and the second sealing part 25 can move up and down along the inner wall surface of the third mounting cavity 16.

[0058] In some embodiments of the present invention, the outer wall surface of the second sealing portion 25 is provided with a groove 251, and the groove 251 and the inner wall surface of the third mounting cavity 16 form a receiving cavity, in which a sealing element is embedded to improve the sealing performance. In one embodiment, the groove 251 extends circumferentially along the second sealing portion 25, and the groove 251 and the inner wall surface of the third mounting cavity 16 form an annular receiving cavity, in which a sealing element is embedded, resulting in a good sealing effect.

[0059] The embodiments of the present invention are applicable to the bidirectional intake valve and small orifice valve of the pulse tube refrigerator.

[0060] The present invention also provides a pulse tube refrigeration system, including a needle valve as described in any of the above embodiments, a compressor and a pulse tube, wherein the valve port 11 of the needle valve is connected to the outlet 12 of the compressor, and the outlet 12 of the needle valve is connected to the pulse tube, and the fluid enters the needle valve through the outlet 12 of the compressor via the valve port 11 to regulate the flow rate, and then enters the pulse tube through the outlet 12.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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; and these 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 the present invention.

Claims

1. A needle valve, characterized in that, include: A valve seat is provided with a valve port and an outlet, and the valve seat has a first mounting cavity and a second mounting cavity that are interconnected. The valve core includes a connected conical valve core portion and an adjusting portion, wherein the cross-sectional area of ​​the conical valve core portion gradually increases from the direction away from the adjusting portion to the direction closer to the adjusting portion; The conical valve core is disposed in the first mounting cavity, and a first flow channel is formed between the conical valve core and the inner wall surface of the first mounting cavity. The valve port is disposed at the end of the first flow channel, and the outlet is connected to the first flow channel. The adjusting part is movably mounted in the second mounting cavity, and the adjusting part can drive the conical valve core to move back and forth along the center line of the valve port to adjust the flow rate of the first flow channel. The outer tangent of the conical valve core forms a conical angle A with its own center line. If 0° < A < 17°, the needle valve introduces negative DC; if 17° < A < 90°, the needle valve introduces positive DC.

2. The needle valve according to claim 1, characterized in that, The conical valve core includes a cone-shaped valve core and a frustum-shaped valve core.

3. The needle valve according to claim 1, characterized in that, The conical valve core is a plurality of conical valve cores connected in sequence, and the cone angle of the conical valve core gradually increases along the direction from the conical valve core to the adjusting part.

4. The needle valve according to claim 1, characterized in that, The valve core further includes a cylindrical valve core portion, which is disposed between the conical valve core portion and the adjusting portion. The cross-sectional area of ​​the end of the conical valve core portion closest to the cylindrical valve core portion is the same as the cross-sectional area of ​​the cylindrical valve core portion. The cross-sectional area of ​​the cylindrical valve core portion is smaller than the cross-sectional area of ​​the adjusting portion. The cylindrical valve core portion is disposed within the first mounting cavity, and a second flow channel is formed between the outer wall surface of the cylindrical valve core portion and the inner wall surface of the first mounting cavity. The outlet is connected to the second flow channel.

5. The needle valve according to claim 4, characterized in that, The valve core further includes a first sealing part, which is disposed between the cylindrical valve core part and the adjusting part, and located in the second mounting cavity. The cross-sectional area of ​​the first sealing part is larger than the cross-sectional area of ​​the first mounting cavity to seal the second flow channel.

6. The needle valve according to claim 5, characterized in that, A third flow channel is formed between the outer wall surface of the first sealing part and the inner wall surface of the second mounting cavity, and the outlet communicates with the third flow channel; The cross-sectional area of ​​the adjusting part is larger than that of the first sealing part, and the outer wall surface of the adjusting part is movably and sealingly connected to the outer wall surface of the second mounting cavity.

7. The needle valve according to claim 4, characterized in that, The outer wall of the adjustment part is provided with an external thread, and the second mounting cavity is provided with an internal thread. The adjustment part is threadedly connected to the second mounting cavity.

8. The needle valve according to claim 7, characterized in that, The length of the conical valve core is L1, the length of the cylindrical valve core is L2, and the length of the external thread is L3, where L3 = L1 + L2.

9. The needle valve according to claim 1, characterized in that, The valve seat has a third mounting cavity, which is located on the side of the second mounting cavity away from the first mounting cavity, and the cross-sectional area of ​​the third mounting cavity is larger than that of the second mounting cavity. The valve core further includes a second sealing part, which is disposed in the third mounting cavity. The second sealing part is located at the end of the adjusting part away from the conical valve core. The outer wall surface of the second sealing part is provided with a groove, which forms a receiving cavity with the inner wall surface of the third mounting cavity to embed the sealing element.

10. A pulse tube cooling system, characterized in that, The device includes a needle valve as described in any one of claims 1 to 9, and further includes a compressor and a pulse tube, wherein the valve port of the needle valve is connected to the outlet of the compressor, and the outlet of the needle valve is connected to the pulse tube.

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