Gas phase modulation integrated device for thermal coupling type multistage pulse tube refrigerator

Abstract

The invention relates to a gas phase modulation integrated device for a thermal coupling type multi-stage pulse tube refrigerator. The gas phase modulation integrated device comprises a high-temperature-stage inertia tube, a gas reservoir assembly, a room-temperature piston and a plate spring assembly. The gas reservoir assembly comprises a first gas reservoir and a second gas reservoir; the high-temperature-level inertia pipe comprises a first inertia pipe and a second inertia pipe, the first inertia pipe is located on the outer side of the gas reservoir assembly, and the second inertia pipe is located in the first gas reservoir; one end of the first inertia tube is connected with a refrigerator high-temperature-stage hot end gas distribution seat, and the other end is connected with the second inertia tube; the plate spring assembly is mounted in the second air reservoir; one end of the room-temperature piston extends into the second air reservoir and is connected with the plate spring assembly, and the other end of the room-temperature piston is connected with a low-temperature-stage hot-end air distribution seat of the refrigerating machine. The plate spring supporting and room temperature piston phase modulation mode is adopted, the phase modulation capacity is greatly improved, the performance and efficiency of the refrigerating machine are improved, the space occupied by the phase modulation device on the periphery of the refrigerating machine is reduced, the structure of the refrigerating machine is more compact, and the reliability of the whole machine is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-temperature refrigeration, and in particular to a gas phase modulation integrated device for a thermally coupled multi-stage pulse tube refrigerator. Background Art

[0002] With the continuous development of science and technology in various industries, the application scope of cryogenic refrigerators has been continuously expanded. They have important applications in aerospace, national defense and military industry, cryogenic superconductivity, medical treatment, transportation and other fields. At the same time, they also put forward higher requirements on the performance, life, mechanical vibration and other indicators of refrigerators.

[0003] Traditional regenerative cryogenic refrigerators have moving parts at the cold end, poor reliability, and large vibrations, which limits their application in many occasions. Pulse tube refrigerators have no moving parts in the low temperature zone, and have outstanding advantages such as high reliability and low mechanical vibration, and have broad application prospects. In order for pulse tube refrigerators to reach liquid hydrogen or lower temperature zones, a multi-stage coupling structural arrangement is required. At present, the common coupling methods are gas coupling and thermal coupling. Gas coupling generally means that the pulse tubes at each stage can only be placed coaxially, relying on the internal gas for gas coupling heat exchange. The gas coupling structure is relatively compact, but because the gas is connected, there is airflow distribution in the pulse tubes at each stage, which is difficult to control quantification, and the pre-cooling stage cannot take cold under this structure, and the efficiency is low. Thermal coupling is to thermally connect the high-temperature pulse tube with the low-temperature pulse tube through a cold chain, relying on metal heat conduction to transfer cold. The airflows between each stage of the thermally coupled pulse tube are independent of each other, and the parameters of each stage can be designed and optimized separately. The pulse tube structure is more flexible and suitable for U-shaped, straight-line and other layout forms. It can achieve coupling connection between each stage of the three-stage and four-stage pulse tubes to achieve a lower cooling temperature. However, the disadvantage is that it will cause the weight and volume of the system to increase.

[0004] The research on phase adjustment mechanism is of great significance to the development of pulse tube refrigerator. Multi-stage pulse tube refrigerator has multiple phase adjustment mechanisms, and the research on multi-stage phase adjustment technology is crucial to improve the performance of refrigerator. At present, the developed phase adjustment methods mainly include small hole phase adjustment, inertial tube phase adjustment, two-way air intake, multi-way bypass, etc. Among them, the coordinated phase adjustment of inertial tube and gas reservoir uses the inertial effect of the alternating flow of working gas in the slender tube to adjust the phase difference between the pressure wave and the mass flow, so as to improve the cold end enthalpy flow. It has the advantages of simple structure, wide phase adjustment range and no increase in compressor power consumption. It is the preferred phase adjustment method for the high temperature stage of pulse tube refrigerator. For low temperature stage phase adjustment, the coordinated phase adjustment method of inertial tube and gas reservoir can also be adopted. However, there are higher requirements for parameters such as inertial tube specifications and gas reservoir volume, and the phase adjustment capacity is difficult to meet actual needs.

[0005] The hot end of each stage of the existing thermally coupled multi-stage pulse tube refrigerator needs to be phased separately. The high-temperature stage mostly adopts the method of coordinated phase adjustment of inertia tube + gas reservoir. Although it can meet the phase adjustment requirements, the inertia tube is generally about 3 meters long, and the gas reservoir also needs to ensure a certain volume. Therefore, the overall structure occupies a large space, and the layout of the refrigerator periphery is difficult. The low-temperature stage can also adopt the method of coordinated phase adjustment of inertia tube + gas reservoir, but the phase adjustment capacity is slightly insufficient, which is not conducive to further reducing the minimum temperature of the pulse tube refrigerator, and at the same time affects the efficiency of the refrigerator. In addition, this method further increases the space occupied by the periphery, resulting in a larger structural size of the whole machine, and the inertia tubes and gas reservoirs at each level need to be additionally fixed, otherwise the inertia tube is prone to twisting and breaking, which is not conducive to the transportation of the refrigerator or its matching with other systems.

[0006] Therefore, there is an urgent need to realize a gas phase-adjusting integrated device for a thermally coupled multi-stage pulse tube refrigerator that can enhance the phase-adjusting capability and improve the refrigerator performance and efficiency. Summary of the invention

[0007] The purpose of the present invention is to provide an integrated gas phase-adjusting device for a thermally coupled multi-stage pulse tube refrigerator. The integrated gas phase-adjusting device can solve the shortcomings of the prior art and adopts a phase-adjusting method of leaf spring support + room temperature piston, which greatly improves the phase-adjusting ability and improves the performance and efficiency of the refrigerator. At the same time, the integrated structure reduces the space occupied by the phase-adjusting device on the periphery of the refrigerator, making the structure of the refrigerator more compact and improving the reliability of the whole machine.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A gas phase-adjusting integrated device for a thermally coupled multi-stage pulse tube refrigerator, the gas phase-adjusting integrated device comprising: a high-temperature inertia tube, a gas reservoir assembly, a room-temperature piston and a leaf spring assembly; the gas reservoir assembly comprises a first gas reservoir and a second gas reservoir which are arranged in sequence and are connected; the high-temperature inertia tube comprises a first inertia tube and a second inertia tube which are connected in sequence, wherein the first inertia tube is located outside the gas reservoir assembly, and the second inertia tube is located inside the first gas reservoir; one end of the first inertia tube is connected to a high-temperature hot end gas distribution seat of the refrigerator, and the other end is connected to the second inertia tube; the leaf spring assembly is installed in the second gas reservoir; one end of the room-temperature piston extends into the second gas reservoir and is connected to the leaf spring assembly, and the other end is connected to a low-temperature hot end gas distribution seat of the refrigerator.

[0010] As a further improvement of the above technical solution, the high-temperature inertia tube adopts a copper tube with a total length of 3m, wherein the outer diameter of the first inertia tube is 3mm, the inner diameter is 2mm, and the length is 1.5m, the outer diameter of the second inertia tube is 4mm, the inner diameter is 3mm, and the length is 1.5m, and the first inertia tube and the second inertia tube are connected by vacuum brazing; the second inertia tube is spiral, ensuring that the spiral outer diameter and height can be placed inside the first gas reservoir.

[0011] As a further improvement of the above technical solution, the first gas reservoir and the second gas reservoir are connected by laser welding to form a gas reservoir assembly; the first gas reservoir and the second gas reservoir are both made of stainless steel.

[0012] As a further improvement of the above technical solution, the first gas reservoir includes a first gas reservoir main body; a first through hole is provided on the top of the first gas reservoir main body, a first supporting platform is provided on the bottom of the first gas reservoir main body, and a second through hole is provided on the first supporting platform; a step-shaped connecting part is provided on the lower end of the first gas reservoir main body; the second gas reservoir includes a second gas reservoir main body; a step-shaped opening is provided on the top of the second gas reservoir main body; a second supporting platform is provided on the inner side of the middle section of the second gas reservoir main body; the leaf spring assembly is placed on the second supporting platform; an extension part is provided at the bottom of the second gas reservoir main body; an outlet is provided on the extension part; the connecting part cooperates with the opening for welding the first gas reservoir and the second gas reservoir together; the connecting part overlaps at the opening, and laser welding is performed at the contact surface between the two, so that the first gas reservoir and the second gas reservoir are connected as one by laser welding.

[0013] As a further improvement of the above technical solution, the high-temperature inertia tube and the high-temperature hot end gas distribution seat of the refrigerator are connected by flame brazing.

[0014] As a further improvement of the above technical solution, a part of the high-temperature inertia tube is processed into a spiral shape, passed through the first through hole on the first gas reservoir and placed on the first supporting platform of the first gas reservoir, and the connection between the high-temperature inertia tube and the first gas reservoir is welded and sealed by flame brazing.

[0015] As a further improvement of the above technical solution, a gap seal is used between the room temperature piston and the second gas reservoir, and the gap between the two is 0.02mm; the other end of the room temperature piston extends into the low-temperature stage pulse tube of the refrigerator, and a gap seal is used between the two, and the gap is 0.02mm.

[0016] As a further improvement of the above technical solution, the leaf spring assembly includes a pad and a first leaf spring and a second leaf spring respectively installed on the upper and lower sides of the pad; the first leaf spring and the second leaf spring have the same structure, both including two washers and a leaf spring located between the two washers; the pad includes an inner pad and an outer pad. A leaf spring is installed in the two washers, and they are placed on the second support platform inside the second air reservoir and on the pad, respectively. The pad includes an inner pad and an outer pad, and then screws are passed through the washers, leaf springs, washers, pads, washers, leaf springs, and washers respectively. The outer screws are installed on the threaded holes of the steps inside the second air reservoir, and the inner screws are installed on the threaded holes of the connecting seat.

[0017] As a further improvement of the above technical solution, the leaf spring assembly is placed on the second supporting platform of the second air reservoir, and is connected to the upper end of the room temperature piston through screws and a connecting seat.

[0018] As a further improvement of the above technical solution, the extension part of the second gas reservoir is inserted into the low-temperature hot-end gas distribution seat, and the second gas reservoir and the low-temperature hot-end gas distribution seat are welded and connected by vacuum brazing; the low-temperature hot-end gas distribution seat is installed on the hot-end flange of the refrigerator.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] (1) The integrated gas phase adjustment device for the heat-coupled multi-stage pulse tube refrigerator described in the present invention can solve the deficiencies in the prior art by integrating the high-temperature inertial tube and the gas reservoir. At the same time, the low-temperature stage uses a room-temperature piston for active phase adjustment and is placed in the high-temperature gas reservoir. Finally, the whole is welded to the hot end of the high-temperature stage of the refrigerator. The low-temperature stage of the integrated phase adjustment device uses a leaf spring support + room-temperature piston phase adjustment method, which greatly improves the phase adjustment capability and improves the performance and efficiency of the refrigerator. At the same time, the integrated structure reduces the space occupied by the phase adjustment device outside the refrigerator, making the structure of the refrigerator more compact and improving the reliability of the whole machine.

[0021] (2) The integrated gas phase adjustment device for the heat-coupled multi-stage pulse tube refrigerator described in the present invention integrates the high-temperature and low-temperature phase adjustment devices into one component, effectively reducing the size of the whole machine, making the whole machine structure more compact, and improving the reliability of the whole machine. At the same time, the device and the refrigerator are welded as a whole, which improves the stability of the whole machine. At the same time, the low-temperature phase adjustment adopts a phase adjustment device of a room temperature piston, which improves the phase adjustment ability, greatly improves the performance of the refrigerator, and improves the efficiency of the refrigerator. Compared with the traditional two-way air intake phase adjustment method, calculations show that under the same pressure ratio, the acoustic power required for the room temperature piston phase adjustment is reduced by nearly 50%, and the efficiency is more than doubled. Experimental results show that under the same input power, compared with the traditional phase adjustment mechanism, the refrigeration efficiency is increased by nearly 70%. The present invention is suitable for heat-coupled two-stage pulse tube refrigerators, and can also provide a reference for the design of phase adjustment devices for three-stage and four-stage pulse tube refrigerators.

[0022] (3) The integrated gas phase adjustment device for the heat-coupled multi-stage pulse tube refrigerator described in the present invention adopts a leaf spring support. Compared with the traditional column spring, the leaf spring can provide a larger radial stiffness for the room temperature piston, ensuring the clearance between the room temperature piston and the pulse tube and the gas reservoir outlet during movement; at the same time, the axial stiffness of the leaf spring support can be adjusted by changing the thickness and number of leaf springs, which is relatively convenient and easy to achieve, and the assembly of the components is also simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the gas phase adjustment integrated device for the heat-coupled multi-stage pulse tube refrigerator of the present invention;

[0024] Figure 2 It is a schematic cross-sectional structure diagram of the integrated gas phase modulation device for the heat-coupled multi-stage pulse tube refrigerator of the present invention;

[0025] Figure 3 This is a schematic diagram of the structure of the first gas reservoir in the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of the second gas reservoir in the present invention;

[0027] Figure 5 It is a schematic cross-sectional structure diagram of the gas phase adjustment integrated device for the heat-coupled multi-stage pulse tube refrigerator of the present invention after being coupled with the hot end flange of the refrigerator;

[0028] Figure 6 This is a curve diagram of the minimum temperature and cooling capacity corresponding to different phase adjustment mechanisms.

[0029] in:

[0030] 1. High temperature grade inertia tube, 2. Gas reservoir assembly, 3. Room temperature piston, 4. Leaf spring, 5. Connecting seat, 6. Gasket, 7. Spacer, 8. High temperature grade hot end gas distribution seat of refrigerator, 9. Low temperature grade hot end gas distribution seat of refrigerator, 10. Hot end flange of refrigerator, 11. First gas reservoir, 12. Second gas reservoir, 13. Flame brazing welding point A, 14. Flame brazing welding point B, 15. Laser welding point C, 16. Vacuum brazing welding point D. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings:

[0032] Low-temperature refrigeration technology is mostly used in aerospace, detection and other scientific and technological fields. Basically, there are requirements for the vibration, life and reliability of the refrigerator, and the pulse tube refrigerator has certain advantages over the traditional Stirling refrigerator in these aspects. At present, the commonly used phase modulation structure has a limited phase modulation range, the system sound field distribution is not ideal, and the loss is large. At the same time, the considerable expansion acoustic work at the hot end of the pulse tube in the higher temperature zone is not recovered, which limits the improvement of the efficiency of the pulse tube refrigerator; the phase modulation mechanism (inertial tube, cryogenic gas reservoir, etc.) on the periphery of the refrigerator occupies a large volume and is heavy. Therefore, for the thermally coupled multi-stage pulse tube refrigerator, it is necessary to further improve the performance and reliability of the pulse tube refrigerator and to increase the product integration as much as possible.

[0033] The present invention proposes an integrated gas phase adjustment device for a heat-coupled multi-stage pulse tube refrigerator, which effectively solves the technical problem of insufficient phase adjustment capability of the low-temperature stage of the pulse tube refrigerator, and overcomes the inherent bias of the traditional pulse tube refrigerator to use inertia tube + gas reservoir phase adjustment. At the same time, it also has the function of recovering expansion work at the hot end, and the high-temperature stage drives the low-temperature stage to jointly adjust the phase, which further improves the expansion efficiency of the pulse tube, and thus improves the performance of the refrigerator. The present invention adopts a room temperature piston + leaf spring structure to provide radial support for the piston movement, solving the technical problems of wear and short life during movement. In terms of the peripheral structure, the present invention integrates the two-stage phase adjustment mechanism and fixes it by welding, solving the technical problems of the complex peripheral structure of the pulse tube refrigerator, large space occupation, difficult layout, and easy breakage and bending of the inertia tube, improving the reliability of the mechanism, and also reducing the volume and weight of the whole machine.

[0034] like Figure 1 The gas phase-adjusting integrated device for a heat-coupled multi-stage pulse tube refrigerator shown in the figure comprises a high-temperature inertial tube 1, a gas reservoir assembly 2, a room-temperature piston 3 and a leaf spring assembly.

[0035] The gas phase adjustment integrated device for a heat-coupled multi-stage pulse tube refrigerator of the present invention can be applied to a heat-coupled two-stage pulse tube refrigerator. The high-temperature stage of the refrigerator adopts a combined phase adjustment method combining a high-temperature inertial tube 1 and a gas reservoir component 2. This inertial tube and gas reservoir coordinated phase adjustment method uses the inertial effect of the alternating flow of the working gas in the slender tube to adjust the phase difference. It has the advantages of simple structure, wide phase adjustment range and no increase in compressor power consumption. It is the preferred phase adjustment method in the pulse tube refrigerator. This method can greatly improve the phase adjustment capability and improve the performance and efficiency of the refrigerator.

[0036] like Figure 2 and Figure 5 As shown, the high-temperature inertial tube 1 includes two sections, a first inertial tube and a second inertial tube, which are arranged in sequence and connected. The first inertial tube is located outside the gas reservoir assembly 2, and the second inertial tube extends into the gas reservoir assembly 2. The second inertial tube is spiral. The high-temperature inertial tube 1 adopts a copper tube with a total length of 3m, wherein the inner diameter of the first inertial tube is 2mm and the length is 1.5m, the inner diameter of the second inertial tube is 3mm and the length is 1.5m, and the first inertial tube and the second inertial tube are connected by vacuum brazing. The dimensions of the first inertial tube and the second inertial tube are obtained through creative labor. First, based on theoretical analysis, the phase angle and mass flow required to be adjusted by the inertial tube are obtained, and then the DeltaEC software based on thermoacoustic theory is used to perform a separate simulation design of the inertial tube, and different inertial tube diameters, lengths and related experimental verifications are carried out on the basis of the design, and finally the inertial tube combination form of the size combination is obtained.

[0037] like Figure 2 and Figure 5 As shown, the gas reservoir assembly 2 includes a first gas reservoir 11 and a second gas reservoir 12 arranged in sequence. The first gas reservoir 11 and the second gas reservoir 12 are both made of stainless steel. The first gas reservoir 11 and the second gas reservoir 12 are connected by laser welding to form a gas reservoir assembly 2. The first gas reservoir and the second gas reservoir are connected in a form that can simplify the internal structure and allow the room temperature piston movement to cause the flow of the low-temperature gas to synchronously affect the high-temperature gas phase adjustment, further improving the phase adjustment capability.

[0038] As a further improvement of the above technical solution, Figure 3As shown, the first gas reservoir 11 includes a first gas reservoir body; a first through hole is provided on the top of the first gas reservoir body, a first supporting platform is provided on the bottom of the first gas reservoir body, and a second through hole is provided on the first supporting platform; a step-shaped connecting portion is provided at the lower end of the first gas reservoir body. The outer diameter of the second inertia tube is 4 mm, and a spiral shape is formed by bending the pipe. The size of the first inertia tube matches the first through hole on the top of the first gas reservoir body. After the first inertia tube passes through the first through hole, it is flame brazed with the second inertia tube. At this time, the first inertia tube and the second inertia tube have formed a whole; then the second inertia tube is placed on the first supporting platform, and finally the first through hole and the first inertia tube are welded by flame welding to ensure the airtightness of the gas reservoir assembly. This structure places the inertia tube in the gas reservoir, effectively reducing the space occupied by the peripheral phase adjustment assembly, and the spiral second inertia tube further reduces the occupied volume. In addition, the second inertia tube is placed on the internal steps of the first gas reservoir, eliminating the stress on the copper tube itself. The two ends of the first inertia tube are also fixed by welding, which reduces the distortion and breakage of the inertia tube caused by transportation and testing, and improves the reliability of the structure.

[0039] As a further improvement of the above technical solution, Figure 4 As shown, the second gas reservoir 12 includes a second gas reservoir body; a stepped opening is provided on the top of the second gas reservoir body, and the opening is used for welding with the opening of the first gas reservoir. A second support platform is provided on the inner side of the middle section of the second gas reservoir body, and a mounting threaded hole is provided on the second support platform; the leaf spring assembly is placed on the second support platform, and the leaf spring assembly is fixed to the second support platform and the connecting seat by screws. The upper side of the connecting seat is connected to the leaf spring assembly by screws, so the room temperature piston drives the leaf spring assembly to move through the connecting seat while reciprocating, and the stiffness of the leaf spring assembly affects the displacement and phase adjustment ability of the room temperature piston. An extension is provided below the second gas reservoir body. An outlet is provided on the extension, which leads to the low temperature level pulse tube side, and its size is matched with the clearance of the room temperature piston 3, so that the phase is adjusted and the work is recovered while ensuring the reciprocating motion.

[0040] As a further improvement of the above technical solution, the connecting portion and the opening cooperate with each other, and each has a step groove that cooperates with each other for positioning during welding, and is used for welding the first gas reservoir 11 and the second gas reservoir 12. The connecting portion overlaps the opening, and laser welding is performed at the contact surface between the two, so that the first gas reservoir 11 and the second gas reservoir 12 are connected as a whole by laser welding. The laser welding point between the first gas reservoir 11 and the second gas reservoir 12 is Figure 5Laser welding point C15. The stainless steel gas tank is laser welded, with high welding strength and easy operation. The stepped groove effectively ensures the welding accuracy and stability.

[0041] like Figure 5 As shown, one end of the high-temperature inertia tube 1 is connected to the high-temperature hot end gas distribution seat 8 of the refrigerator. The high-temperature inertia tube 1 and the high-temperature hot end gas distribution seat 8 of the refrigerator are connected by flame brazing. The connection between the high-temperature inertia tube 1 and the high-temperature hot end gas distribution seat 8 of the refrigerator is Figure 5 The flame brazing welding point A13 in the middle. The other end of the high-temperature inertia tube 1 extends into the first gas reservoir 11, and the high-temperature inertia tube 1 located in the first gas reservoir 11 is spiral. The high-temperature inertia tube extending into the interior of the gas reservoir assembly 2 is placed on the first supporting platform. A certain length of the inertia tube 1 is formed into a spiral shape through a bending process, and after passing through the first through hole on the first gas reservoir 11, it is placed on the first supporting platform of the first gas reservoir 11. The connection between the high-temperature inertia tube 1 and the first gas reservoir 11 is welded and sealed by flame brazing. The connection is Figure 5 The flame brazing in the welding point is B14.

[0042] As a further improvement of the above technical solution, one end of the room temperature piston 3 extends into the second gas reservoir 12; one end of the room temperature piston 3 extends through the outlet into the second gas reservoir 12. A gap seal is used between the room temperature piston 3 and the second gas reservoir 12, and the gap between the two is 0.02mm; the other end of the room temperature piston 3 extends into the low temperature pulse tube of the refrigerator, and a gap seal is also used between the two, and the gap is 0.02mm.

[0043] As a further improvement of the above technical solution, the leaf spring assembly includes a cushion block 7 and a first leaf spring and a second leaf spring respectively installed on the upper and lower sides of the cushion block 7; the first leaf spring and the second leaf spring have the same structure, both including two washers 4 and a leaf spring 4 located between the two washers 4; the cushion block 7 includes an inner cushion block and an outer cushion block. A leaf spring 4 is installed in the two washers 4, and is placed on the second support platform inside the second gas reservoir 12 and on the cushion block 7 respectively. The cushion block 7 includes an inner cushion block and an outer cushion block, and then the washer 6, the leaf spring 4, the washer 6, the cushion block 7, the washer 6, the leaf spring 4, and the washer 6 are passed through the screws respectively. The outer screws are installed on the threaded holes of the steps inside the second gas reservoir 12, and the inner screws are installed on the threaded holes of the connecting seat 5. The specifications of each part in the leaf spring assembly, such as leaf spring stiffness, washer height and other parameters, need to be determined through preliminary tests. The assembled leaf spring assembly is placed on the second support platform of the second gas reservoir 12, and is connected to the upper end of the room temperature piston 3 through screws and the connecting seat 5. The extension of the second gas reservoir 12 is inserted into the low temperature hot end gas distribution seat 9, at the connection between the second gas reservoir 12 and the low temperature hot end gas distribution seat 9, that is, Figure 5 Apply solder to the vacuum brazing welding point D16 in the vacuum brazing process, and weld the second gas reservoir 11 to the low-temperature hot end gas distribution seat 9 by vacuum brazing. Finally, the low-temperature hot end gas distribution seat 9 is installed on the hot end flange 10 of the refrigerator to complete the assembly.

[0044] The working principle of the gas phase adjustment integrated device for the heat-coupled multi-stage pulse tube refrigerator of the present invention is as follows:

[0045] After the thermally coupled two-stage pulse tube refrigerator is started, the refrigerator performs compression movement, and the internal working fluid gas flows from the hot end of the high-temperature stage through the inertia tube 1 into the gas reservoir component 2, changing the motion state of the hot end gas and completing the phase adjustment function. At the same time, since the first gas reservoir is connected to the second gas reservoir, a part of the gas can assist in the phase adjustment of the low-temperature gas. Afterwards, when the refrigerator performs expansion movement, the internal gas flows back to the hot end of the high-temperature stage from the gas reservoir component 2, completing a working cycle. The gas at the hot end of the low-temperature stage also undergoes compression and expansion processes. The gas after passing through the pulse tube pushes the room temperature piston 3 to move. The leaf spring component has a certain mechanical stiffness, which can control the reciprocating motion of the room temperature piston 3, complete the phase adjustment at the same time, and recover part of the expansion work. The device can achieve phase angle adjustment of the working fluid gas pressure wave and mass flow in different temperature zones, thereby improving the performance of the refrigerator.

[0046] In the present invention, the low-temperature stage of the refrigerator eliminates the commonly used low-temperature stage inertia tube + gas reservoir phase adjustment method, and adopts a room-temperature piston + leaf spring structure for phase adjustment. The structure of the inertia tube + first gas reservoir can meet the phase adjustment requirements of the high-temperature gas, and the first and second gas reservoirs are connected, and the high-temperature gas can also play a role in assisting the low-temperature stage phase adjustment. The inertia tube is bent and rotated into the first support platform inside the first gas reservoir, and the first and second gas reservoirs are laser welded to form a single gas reservoir assembly, integrating the phase adjustment structure. The present invention adopts the phase adjustment method of room-temperature piston + leaf spring to solve the problem of insufficient low-temperature stage phase adjustment ability of multi-stage pulse tube refrigerators, and improves the efficiency and performance of the refrigerator; the leaf spring structure used can provide more suitable radial stiffness support for the movement of the room-temperature piston, ensure the long-term gap movement of the piston at the outlet of the second gas reservoir, and improve the service life of the phase adjustment mechanism.

[0047] The present invention solves the technical problem that the two-stage phase-adjusting mechanism on the periphery of a multi-stage pulse tube refrigerator is large in size and cannot be laid out, thereby reducing the space occupied by the outside of the refrigerator and reducing the volume of the entire machine. At the same time, the first and second gas reservoirs are integrated, the long low-temperature inertial tube structure is removed, and the weight of the entire machine is reduced. The high-temperature inertial tube is spirally built into the gas reservoir, further reducing the volume occupied by the phase-adjusting mechanism. At the same time, the inertial tube is placed on a supporting platform, and each connection position is fixed by welding, which reduces the stress on the phase-adjusting mechanism itself, reduces the occurrence of bending, twisting, breaking, etc. caused by the free state of the inertial tube, and further improves the reliability of the phase-adjusting mechanism.

[0048] The specific assembly steps of the gas phase adjustment integrated device for the heat-coupled multi-stage pulse tube refrigerator of the present invention before use are as follows:

[0049] S1. Select a high-temperature inertial tube 1 of appropriate length, bend a portion of it into a spiral shape and place it in the first gas reservoir 11, and let the remaining straight tube pass through the first through hole above the first gas reservoir 11. Place the spiral portion of the high-temperature inertial tube 1 on the first support platform in the first gas reservoir 11.

[0050] S2. Place a leaf spring 4 between two washers 6, and then place it on the upper side of the pad 7. Then place two washers 6 with the same structural position as the upper side and a leaf spring 4 between the two washers 6 on the lower side of the pad 7 to form a leaf spring assembly. Finally, connect the leaf spring 4, the washer 6, and the pad 7 with screws and install them into the threaded holes of the connecting seat 5 and the second support platform in the second air reservoir 12. The position accuracy must be ensured during the assembly of the leaf spring assembly. After the assembly is completed, the relative position of each part can be determined by laser welding to improve the stability of the assembly.

[0051] S3. Vacuum braze the second gas reservoir 12 and the low-temperature hot-end gas distribution seat 9 at the vacuum brazing welding point D16 to form an assembly, and then insert the room-temperature piston 3 into the low-temperature pulse tube through the outlet on the second gas reservoir 12; place the leaf spring assembly on the second support platform of the second gas reservoir 12, and assemble the leaf spring assembly with the room-temperature piston 3 through the connecting seat 5. During assembly, the coaxiality of the room-temperature piston 3, the pulse tube and the outlet below the second gas reservoir 12 must be ensured; then, install the overall structure into the hot-end flange 10 of the refrigerator through the low-temperature hot-end gas distribution seat 9.

[0052] S4, assemble the first gas reservoir 11 equipped with the high-temperature inertia tube 1 and the second gas reservoir 12 equipped with the room-temperature piston 3 and the leaf spring assembly together, and weld them at the side welding point (i.e. Figure 5 The laser welding point C15) is laser welded to form a closed gas storage component 2.

[0053] S5. Install the high-temperature hot-end gas distribution seat 8 into the hot-end flange 10 of the refrigerator, and insert the other end of the high-temperature inertia tube 1 into the high-temperature hot-end gas distribution seat 8. After determining the position, flame brazing is performed at the flame brazing welding point A13 and the flame brazing welding point B14 to fix the position of each part.

[0054] After step S5 is completed, the assembly and welding of the integrated gas phase adjustment device for the thermally coupled multi-stage pulse tube refrigerator and the coupling with the thermally coupled two-stage pulse tube refrigerator are completed, forming a complete refrigerator.

[0055] With the same pulse tube refrigerator parameters (total power, frequency, gas pressure, etc.), different phase adjustment mechanisms are used to obtain the lowest temperature and cooling capacity experimental results through testing. Figure 6 The comparison between the relevant design parameters and the experimental results is shown in Table 1.

[0056] Table 1 Comparison of design parameters and experimental results of different phase adjustment mechanisms

[0057]

[0058] Depend on Figure 6 As shown in the test results in Table 1, under the premise of a total power of 440W and the same other operating parameters, the integrated device can be used for phase adjustment to obtain a no-load temperature of 10.23K, and the cooling capacity at 20K is also increased from the previous 0.5W to 0.95W. Compared with the traditional inertial tube + gas reservoir phase adjustment method, the relative Carnot efficiency of the new structure is increased by nearly 90%. The experiment can prove that the integrated phase adjustment device can better improve the efficiency of the refrigerator and improve the performance of the refrigerator.

[0059] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the scope of protection determined by the claims of the present invention.

Claims

1. A gas phase adjustment integrated device for a heat-coupled multi-stage pulse tube refrigerator, characterized in that: The gas phase adjustment integrated device comprises: a high-temperature inertial tube (1), a gas reservoir component (2), a room-temperature piston (3) and a leaf spring component; The gas reservoir component (2) comprises a first gas reservoir (11) and a second gas reservoir (12) which are arranged in sequence and are connected to each other; The high-temperature inertia tube (1) comprises a first inertia tube and a second inertia tube which are connected in sequence, wherein the first inertia tube is located outside the gas reservoir component (2), and the second inertia tube is located inside the first gas reservoir (11); one end of the first inertia tube is connected to a high-temperature hot end gas distribution seat (8) of a refrigerator, and the other end is connected to the second inertia tube; The leaf spring assembly is installed in the second gas reservoir (12); one end of the room temperature piston (3) extends into the second gas reservoir (12) and is connected to the leaf spring assembly, and the other end is connected to the low temperature stage hot end gas distribution seat (9) of the refrigerator.

2. The gas phase adjustment integrated device for a heat-coupled multi-stage pulse tube refrigerator according to claim 1, characterized in that: The high-temperature inertia tube (1) is a copper tube with a total length of 3 m, wherein the first inertia tube has an outer diameter of 3 mm, an inner diameter of 2 mm, and a length of 1.5 m, and the second inertia tube has an outer diameter of 4 mm, an inner diameter of 3 mm, and a length of 1.5 m. The first inertia tube and the second inertia tube are connected by vacuum brazing; and the second inertia tube is spiral.

3. The integrated gas phase modulation device for a heat-coupled multi-stage pulse tube refrigerator according to claim 1, characterized in that: The first gas reservoir (11) and the second gas reservoir (12) are connected by laser welding to form a gas reservoir assembly (2); the first gas reservoir (11) and the second gas reservoir (12) are both made of stainless steel.

4. The integrated gas phase modulation device for a heat-coupled multi-stage pulse tube refrigerator according to claim 1, characterized in that: The first gas reservoir (11) comprises a first gas reservoir body; a first through hole is provided on the top of the first gas reservoir body, a first support platform is provided on the bottom of the first gas reservoir body, and a second through hole is provided on the first support platform; a step-shaped connecting portion is provided at the lower end of the first gas reservoir body; The second gas reservoir (12) comprises a second gas reservoir body; a stepped opening is arranged on the top of the second gas reservoir body; a second support platform is arranged inside the middle section of the second gas reservoir body; the leaf spring assembly is placed on the second support platform; an extension portion is arranged below the second gas reservoir body; an outlet is arranged on the extension portion; The connecting portion cooperates with the opening and is used for welding the first gas reservoir (11) and the second gas reservoir (12) together; the connecting portion overlaps the opening, and laser welding is performed at the contact surface between the two, so that the first gas reservoir (11) and the second gas reservoir (12) are connected as a whole by laser welding.

5. The integrated gas phase modulation device for a heat-coupled multi-stage pulse tube refrigerator according to claim 1, characterized in that: The high-temperature inertia tube (1) and the high-temperature hot end gas distribution seat (8) of the refrigerator are connected by flame brazing.

6. The integrated gas phase modulation device for a heat-coupled multi-stage pulse tube refrigerator according to claim 4, characterized in that: After a portion of the high-temperature inertia tube (1) is processed into a spiral shape, it passes through a first through hole on the first gas reservoir (11) and is placed on a first support platform of the first gas reservoir (11). The connection between the high-temperature inertia tube (1) and the first gas reservoir (11) is welded and sealed by flame brazing.

7. The gas phase adjustment integrated device for a heat-coupled multi-stage pulse tube refrigerator according to claim 1, characterized in that: A gap seal is used between the room temperature piston (3) and the second gas reservoir (12), and the gap between the two is 0.02 mm; the other end of the room temperature piston (3) extends into the low temperature pulse tube of the refrigerator, and a gap seal is used between the two, and the gap is 0.02 mm.

8. The integrated gas phase modulation device for a heat-coupled multi-stage pulse tube refrigerator according to claim 4, characterized in that: The leaf spring assembly comprises a cushion block (7) and a first leaf spring and a second leaf spring respectively mounted on the upper and lower sides of the cushion block (7); the first leaf spring and the second leaf spring have the same structure, both comprising two washers (4) and a leaf spring (4) located between the two washers (4); the cushion block (7) comprises an inner cushion block and an outer cushion block.

9. The gas phase adjustment integrated device for a heat-coupled multi-stage pulse tube refrigerator according to claim 1, characterized in that: The leaf spring assembly is placed on the second support platform of the second air reservoir (12) and is connected to the upper end of the room temperature piston (3) via screws and a connecting seat (5).

10. The gas phase adjustment integrated device for a heat-coupled multi-stage pulse tube refrigerator according to claim 1, characterized in that: The extension of the second gas reservoir (12) is inserted into the low-temperature hot-end gas distribution seat (9), and the second gas reservoir (12) and the low-temperature hot-end gas distribution seat (9) are welded and connected by vacuum brazing; the low-temperature hot-end gas distribution seat (9) is installed on the hot-end flange (10) of the refrigerator.

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