Heat dissipation device for hot end of cold head of pulse tube refrigerator and pulse tube refrigerator

Abstract

The heat dissipation device comprises an auxiliary exhaust valve and an auxiliary air inlet valve, a heat exchange structure is arranged on the cold head hot end, the auxiliary air inlet valve is connected with a compressor high-pressure pipeline, and the auxiliary exhaust valve is connected with a compressor low-pressure pipeline. Meanwhile, the auxiliary air inlet valve and the auxiliary exhaust valve are connected with the heat exchange structure through auxiliary connecting pipes respectively, and flow control devices are arranged on the auxiliary connecting pipes. An auxiliary air inlet valve is opened, an auxiliary exhaust valve is closed, part of low-temperature and high-pressure helium formed through cooling of the heat exchanger enters the heat exchange structure through the auxiliary air inlet valve and an auxiliary connecting pipe to exchange heat with the hot end of the cold head so as to be cooled, and the low-temperature and high-pressure helium absorbs heat to form high-temperature and high-pressure helium; an auxiliary exhaust valve is opened, an auxiliary air inlet valve is closed, and high-temperature and high-pressure helium enters a compressor low-pressure pipeline through an auxiliary connecting pipe and the auxiliary exhaust valve; the flow control device is used for controlling helium flow according to the heating condition of the hot end of the cold head. The heat dissipation device provided by the invention is good and controllable in heat dissipation effect and small in vibration.

Description

Technical Field

[0001] The invention relates to low-temperature refrigeration equipment, in particular to a heat dissipation device for a cold head hot end of a pulse tube refrigerator and a pulse tube refrigerator. Background Art

[0002] A typical GM pulse tube refrigerator system has a cold head and a compressor, using helium as a circulating working fluid. The cold head acts as an expander, expanding the low-temperature and high-pressure helium delivered by the compressor at the cold end of the cold head, absorbing heat and generating cold. After the low-temperature and high-pressure helium expands at the cold end of the cold head, it transfers the heat from the cold end of the cold head to the hot end of the cold head through the regenerator, turning into high-temperature and low-pressure helium, which dissipates heat at the hot end of the cold head, causing its temperature to rise. The high-temperature and low-pressure helium eventually returns to the compressor, and becomes high-temperature and high-pressure helium after being compressed by the pressure pack. A heat exchanger is configured in the compressor, which is arranged at the outlet of the pressure pack. The high-temperature and high-pressure helium generated by the pressure pack is cooled by water and becomes low-temperature and high-pressure helium, which enters the cold head to start the next refrigeration cycle.

[0003] The motor, valve group and cold head of the GM pulse tube refrigerator are separated to reduce vibration. The distance between the inlet and exhaust pipes and the hot end of the cold head is relatively far. The low-temperature and high-pressure helium formed by cooling has been heated up by heat exchange with the returning high-temperature and low-pressure helium in the connecting pipe, and cannot provide effective heat dissipation for the hot end of the cold head. The heat accumulation at the hot end of the cold head of the GM pulse tube refrigerator is relatively large during the cooling process, and the heat accumulation at the hot end of the cold head is relatively reduced during the low-temperature stabilization process. When natural convection is used to passively dissipate heat from the hot end of the cold head, the heat dissipation is small. In CN118168181A, a fan is used to perform forced convection heat dissipation on the hot end of the cold head, which can improve the heat dissipation effect. At the same time, the fan can be controlled to start during the cooling process to increase the heat dissipation, and the fan can be turned off during the low-temperature stabilization process to reduce the impact of its vibration on the cold head, but turning off the heat dissipation will reduce some refrigeration performance.

[0004] The temperature of the hot end of the cold head has a certain influence on the cooling time of the pulse tube refrigerator and the cooling capacity at low temperatures. Compared with the environmental conditions of 0°C in winter, the secondary performance of the GM pulse tube refrigerator at 40°C in summer is attenuated by 10% to 20%. Continuous heat dissipation at the hot end of the cold head can improve the cooling performance of the pulse tube refrigerator. In some applications, such as dilution refrigerators, there are relatively strict requirements on the overall cooling time, and higher requirements on the performance of the pulse tube refrigerator at low temperatures. It is hoped that the cooling time is as short as possible, and the cooling capacity is further improved when the low temperature is stable. This puts higher requirements on the heat dissipation of the hot end of the cold head. The heat dissipation device needs to have small vibration during operation and dynamically adjust the heat dissipation capacity according to the heat generation of the hot end of the cold head. Summary of the invention

[0005] Purpose of the invention: The first purpose of the present invention is to provide a heat dissipation device which can realize efficient and controllable heat exchange between the cold head and the hot end of a pulse tube refrigerator and has low vibration characteristics without introducing traditional air cooling and water cooling equipment; The second purpose of the present invention is to provide a pulse tube refrigerator with the heat dissipation device.

[0006] Technical solution: A heat dissipation device for the hot end of a cold head of a pulse tube refrigerator of the present invention comprises an auxiliary valve group, the auxiliary valve group comprises an auxiliary exhaust valve and an auxiliary intake valve, a heat exchange structure is arranged on the hot end of the cold head, the auxiliary intake valve is connected to the high-pressure pipeline of the compressor, the auxiliary exhaust valve is connected to the low-pressure pipeline of the compressor, and the auxiliary intake valve and the auxiliary exhaust valve are respectively connected to the heat exchange structure via an auxiliary connecting pipe, and a flow control device is arranged on the auxiliary connecting pipe; the auxiliary intake valve is opened and the auxiliary exhaust valve is closed, and a part of the low-temperature and high-pressure helium formed by cooling the heat exchanger enters the heat exchange structure through the auxiliary intake valve and the auxiliary connecting pipe to exchange heat with the hot end of the cold head to cool it down, and the low-temperature and high-pressure helium absorbs heat to form high-temperature and high-pressure helium; the auxiliary exhaust valve is opened and the auxiliary intake valve is closed, and the high-temperature and high-pressure helium enters the low-pressure pipeline of the compressor through the auxiliary connecting pipe and the auxiliary exhaust valve; the flow control device is used to control the helium flow according to the heating condition of the hot end of the cold head.

[0007] Furthermore, the heat exchange structure includes a heat dissipation pipeline, which has a heat dissipation pipeline inlet and outlet for connecting the auxiliary connecting pipe; the heat dissipation pipeline is wound around the hot end surface of the cold head.

[0008] Furthermore, the hot end surface of the cold head has a groove adapted to the heat dissipation pipeline, and the heat dissipation pipeline is fixed in the groove.

[0009] Furthermore, the heat exchange structure includes a heat dissipation cavity formed inside the hot end of the cold head, and the heat dissipation cavity has a heat dissipation cavity inlet and outlet for connecting the auxiliary connecting pipe.

[0010] Furthermore, the heat dissipation cavity wall is provided with fins and micro-channels to enhance heat exchange.

[0011] The present invention provides two heat exchange structures, namely, a heat dissipation pipeline wound around the surface of the hot end of the cold head or a heat dissipation cavity formed inside the hot end of the cold head, wherein the heat dissipation pipeline provides basic cooling capacity, and the heat dissipation cavity can increase the heat exchange effect and provide greater cooling capacity through the fins and tiny flow channels arranged inside.

[0012] Furthermore, the flow control device adopts a solenoid valve or a needle valve.

[0013] A pulse tube refrigerator of the present invention comprises a main valve group and the heat dissipation device, wherein the main valve group comprises a main exhaust valve and a main intake valve; the main exhaust valve is connected to the low-pressure pipeline of the compressor, the main intake valve is connected to the high-pressure pipeline of the compressor, and the main exhaust valve and the main intake valve are respectively connected to the cold head via the main connecting pipe; the main intake valve is opened and the main exhaust valve is closed to realize the intake process of the cold head; the main exhaust valve is opened and the main intake valve is closed to realize the deflation process of the cold head.

[0014] Furthermore, the functions of the main exhaust valve, the main intake valve, the auxiliary exhaust valve and the auxiliary intake valve are realized by a rotary valve.

[0015] Furthermore, the rotary valve includes a valve stator and a valve rotor, the valve rotor has a high-pressure recess at the center and a low-pressure recess around it; the valve stator has a central through hole at the center and has a first surrounding through hole connected to the cold head and a second surrounding through hole connected to the heat exchange structure around it; the high-pressure recess is always connected to the high-pressure pipeline of the compressor through the central through hole; the low-pressure recess is always connected to the low-pressure pipeline of the compressor through the cover body or the motor low-pressure chamber; the valve rotor rotates periodically, so that the high-pressure recess and the low-pressure recess are alternately connected or disconnected with the first surrounding through hole and the second surrounding through hole of the valve stator, thereby realizing the opening and closing functions of the main valve group and the auxiliary valve group.

[0016] Furthermore, the pulse tube refrigerator includes a small-hole gas reservoir bidirectional air inlet pulse tube refrigerator and a four-valve pulse tube refrigerator.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0018] The heat dissipation device provided by the present invention, on the one hand, realizes the function of guiding the cooled high-pressure helium to the hot end of the cold head for effective heat dissipation thereof, and on the other hand, realizes the function of cooling the hot end of the cold head again by producing an expansion refrigeration and heat absorption effect through exhausting high pressure to low pressure, and simultaneously realizes the function of transferring the heat of the hot end of the cold head of the pulse tube refrigerator to the exhaust pipe and the heat exchanger in the compressor, so that the existing water cooling can be used for heat dissipation without the need to introduce new cooling water pipelines or air cooling equipment.

[0019] A flow control device is provided on the connecting pipe of the heat sink to provide appropriate heat dissipation capacity according to demand. There are no moving parts inside the heat sink, and the vibration source is only generated by the filling and deflation of helium when the high and low pressures are switched. The vibration magnitude is small, the same as that of the pulse tube. The air cooling or water cooling proposed in CN118168181A is a mechanical structure or liquid flow impact, with large vibration and average heat dissipation effect. The present invention has a simple structure, smaller vibration, and the gas expansion refrigeration absorbs additional heat and has a better heat dissipation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is a schematic diagram of the structure of a typical two-stage pulse tube refrigerator with bidirectional air inlet in a small-hole gas reservoir;

[0021] Figure 2 It is a structural schematic diagram of a two-stage pulse tube refrigerator with a small-hole gas reservoir and bidirectional air intake provided by an embodiment of the present invention;

[0022] Figure 3 is a schematic structural diagram of a rotary valve in an embodiment of the present invention;

[0023] Figure 4 is a schematic diagram of a heat exchange structure in an embodiment of the present invention;

[0024] Figure 5 yes Figure 4 Exploded diagram of

[0025] Figure 6 1 is a schematic diagram of the working sequence of the rotary valve in one cycle according to an embodiment of the present invention;

[0026] Figure 7 Schematic diagram of another heat exchange structure in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] Attached Figures 1 to 7 The reference numerals in the figures are as follows:

[0029] 1, compressor; 11, vortex pressure pack; 12, heat exchanger; 13, compressor low-pressure pipeline; 14, compressor high-pressure pipeline; 15, cooling water outlet; 16, cooling water inlet;

[0030] 2, rotary valve; V1, main exhaust valve; V2, main intake valve; V3, auxiliary exhaust valve; V4, auxiliary intake valve; 21, valve stator; 211, first peripheral through hole; 212, second peripheral through hole; 213, center through hole; 22, valve rotor; 221, low pressure concave portion; 222, high pressure concave portion; 23, main connecting pipe; 24, auxiliary connecting pipe; 25, flow control device;

[0031] 3, cold head; 41, secondary orifice valve; 42, secondary two-way air intake valve; 43, primary two-way air intake valve; 44, primary orifice valve; 5, hot end of cold head; 5a, groove; 6, heat dissipation pipeline; 6a, heat dissipation pipeline inlet and outlet; 62, heat dissipation cavity; 62a, heat dissipation cavity inlet and outlet; 62b, fin; 71, cylinder flange; 72, primary pulse tube; 73, secondary pulse tube; 74, primary regenerator; 75, primary cold end heat exchanger; 76, primary cold end; 77, secondary regenerator; 78, secondary cold end heat exchanger; 79, secondary cold end; 81, secondary gas reservoir; 82, primary gas reservoir.

[0032] Figure 1 The figure shows a typical structure of a two-stage pulse tube refrigerator with bidirectional air intake in a small-hole gas reservoir, including a compressor 1, a rotary valve 2 and a cold head 3. The compressor 1 provides low-temperature and high-pressure helium and recovers high-temperature and low-pressure helium. The cold head 3 is an expander, which expands and cools the low-temperature and high-pressure helium at the cold end to convert it into high-temperature and low-pressure helium. The rotary valve 2 controls the high and low-pressure helium to enter and exit the cold head 3.

[0033] A refrigeration cycle includes two processes: high-pressure air intake and low-pressure exhaust:

[0034] First, the intake process of the cold head 3 is as follows: the main intake valve V2 is opened and the main exhaust valve V1 is closed. The high-temperature and high-pressure helium in the high-pressure pipeline 14 of the compressor is converted into low-temperature and high-pressure helium after heat exchange with cooling water through the heat exchanger 12. After passing through the main intake valve V2 and the main connecting pipe 23, it is divided into a first flow path and a second flow path to enter the cold head 3. The first flow path passes through the primary regenerator 74, the primary cold end 76, the primary cold end heat exchanger 75, the primary pulse tube 72, and the primary orifice valve 44 in sequence to enter the primary gas reservoir 82. The second flow path passes through the primary regenerator 74, the secondary regenerator 77, the secondary cold end 79, the secondary cold end heat exchanger 78, the secondary pulse tube 73, and the secondary orifice valve 41 in sequence to enter the secondary gas reservoir 81.

[0035] This is followed by the deflation process of the cold head 3, in which the main exhaust valve V1 is opened and the main intake valve V2 is closed. The helium after expansion and refrigeration returns from the primary and secondary gas reservoirs along the above two flow paths in reverse, expands and absorbs heat to generate cold at the primary cold end 76 and the secondary cold end 79, and then enters the compressor low-pressure pipeline 13 through the secondary regenerator 77, the primary regenerator 74, the main connecting pipe 23, and the main exhaust valve V1, and is re-formed into high-temperature and high-pressure helium through the vortex compression bag 11 and enters the compressor high-pressure pipeline 14, and then the next refrigeration cycle is carried out.

[0036] In addition to the above two flow paths, a DC bypass flow path is introduced by using a secondary two-way air intake valve 42 and a primary two-way air intake valve 43, which forms a phase adjustment structure with the secondary orifice valve 41, the primary orifice valve 44, the secondary gas reservoir 81 and the primary gas reservoir 82 to improve the phase distribution of the pulse tube refrigerator and enhance the performance of the pulse tube refrigerator.

[0037] The common GM pulse tube refrigerator not only uses a small hole gas reservoir for two-way air intake as a phase adjustment structure, but also has a four-valve pulse tube refrigerator that directly controls the phase through a rotary valve.

[0038] During the cooling process of the GM pulse tube refrigerator, the cold head hot end 5 is more likely to accumulate heat and more difficult to dissipate heat for the following reasons:

[0039] The low-pressure and high-temperature helium gas that has expanded and absorbed heat at the secondary cold end 79 and the primary cold end 76 gradually transfers the heat to the cold head hot end 5 through the regenerator, and the cold head hot end 5 uses natural convection to passively dissipate heat. The GM pulse tube refrigerator adopts a split arrangement of the valve group and the cold head 3, and the main connecting pipe 23 is relatively long, so more low-pressure and high-temperature helium gas that has absorbed heat will be retained, and the residence time of the low-pressure and high-temperature helium gas will also be longer, resulting in more heat accumulation. At the same time, the cooled low-pressure and high-pressure helium gas exchanges heat with the low-pressure and high-pressure helium gas after passing through the main connecting pipe 23. On the one hand, the heat of the low-pressure and high-temperature helium gas in the main connecting pipe 23 returns to the cold head hot end 5 and is difficult to discharge. On the other hand, it weakens the ability of the low-pressure and high-pressure helium gas to dissipate heat and cool the cold head hot end 5. Therefore, it is difficult for the cold head hot end 5 of the GM pulse tube refrigerator to dissipate heat.

[0040] Generally speaking, the cold head hot end 5 of the GM pulse tube refrigerator can be cooled by air or water to perform forced convection heat exchange to enhance its heat dissipation capacity. However, this method will introduce additional vibration and the heat exchange effect is limited.

[0041] The embodiment of the present invention provides a heat dissipation device that can provide better heat exchange effect and less vibration. Figure 2 The structure shown is a two-stage pulse tube refrigerator with a small-hole gas reservoir and two-way air intake and a heat dissipation device.

[0042] The main technical concept of the present invention is to lead a small stream of low-temperature high-pressure helium gas cooled by the heat exchanger 12 from the compressor high-pressure pipeline 14 to enter the heat exchange structure arranged on the hot end 5 of the cold head. One implementation of the heat exchange structure is to coil the heat dissipation pipeline 6 on the surface of the hot end 5 of the cold head. To this end, the rotary valve 2 in the present invention is based on the rotary valve of the typical small-hole gas reservoir two-way air intake refrigerator, and an auxiliary valve group is added to control the supply and exhaust of the heat dissipation device. The auxiliary valve group is Figure 2 The auxiliary exhaust valve V3 and the auxiliary intake valve V4 are shown in FIG.

[0043] Figure 3 2 is a schematic diagram of the structure of the rotary valve 2 with an auxiliary valve group added. The rotary valve 2 includes a valve rotor 22 and a valve stator 21. The valve rotor 22 has a high-pressure recess 222 at the center and a low-pressure recess 221 around it. The valve stator 21 has a central through hole 213 connected to the compressor high-pressure pipeline 14 at the center, and has a first peripheral through hole 211 connected to the cold head 3 and a second peripheral through hole 212 connected to the heat dissipation pipeline 6 around it. The high-pressure recess 222 is always connected to the compressor high-pressure pipeline 14 through the central through hole 213, and the low-pressure recess 221 is always connected to the compressor low-pressure pipeline 13 through the cover or the motor low-pressure chamber.

[0044] The valve rotor 22 rotates periodically, so that the high-pressure recess 222 and the low-pressure recess 221 are alternately connected or disconnected with the first peripheral through hole 211 and the second peripheral through hole 212 of the valve stator 21, so as to realize the opening and closing functions of the main valve group and the auxiliary valve group, and further realize the inflation and deflation of the cold head 3 or the heat dissipation pipeline 6. When the first peripheral through hole 211 is connected with the high-pressure recess 222, the main intake valve V2 is opened; when the first peripheral through hole 211 is connected with the low-pressure recess 221, the main exhaust valve V1 is opened. When the second peripheral through hole 212 is connected with the high-pressure recess 222, the auxiliary intake valve V4 is opened; when the second peripheral through hole 212 is connected with the low-pressure recess 221, the auxiliary exhaust valve V3 is opened.

[0045] Combination Figure 4 and Figure 5 , the heat dissipation pipeline 6 is a closed pipeline, and has a heat dissipation pipeline inlet and outlet 6a as its only inlet and outlet. The heat dissipation pipeline 6 is connected to the auxiliary connecting pipe 24 through the heat dissipation pipeline inlet and outlet 6a. A flow control device 25 is set on the auxiliary connecting pipe 24 to control the helium flow in and out of the heat dissipation pipeline 6. The flow control device 25 can adopt a needle valve, a solenoid valve, etc. When a solenoid valve is adopted, the solenoid valve control module can be combined with the inverter control module to write a control program to automatically control the operation of the pulse tube refrigerator and the heat dissipation of the hot end of the cold head. When a needle valve is adopted, manual control is performed according to the actual heat dissipation demand of the hot end of the cold head. During the cooling process, when the hot end of the cold head is seriously heated, the opening of the flow control device 25 is increased to increase the helium flow and heat exchange efficiency of the heat dissipation device. In the stable process after cooling, the hot end of the cold head heats up smoothly, and the opening of the flow control device 25 can be appropriately reduced.

[0046] In one cycle, first, the auxiliary air intake valve V4 is opened and the auxiliary air exhaust valve V3 is closed, and the low-temperature and high-pressure helium enters the heat dissipation pipeline 6 through the auxiliary air intake valve V4 and the heat dissipation pipeline inlet and outlet 6a. The heat dissipation pipeline 6 is fixed by the groove 5a on the surface of the hot end 5 of the cold head. The low-temperature and high-pressure helium passes through the pipe wall and exchanges heat with the hot end 5 of the cold head to cool it down. The helium in the heat dissipation pipeline 6 absorbs heat to form high-temperature and high-pressure helium and is stored in the heat dissipation pipeline 6. Subsequently, the auxiliary air exhaust valve V3 is opened and the auxiliary air intake valve V4 is closed, and the heat dissipation pipeline 6 is connected to the low-pressure pipeline 13 of the compressor through the auxiliary air exhaust valve V3. The high-temperature and high-pressure helium in the heat dissipation pipeline 6 is then discharged. At the same time, the high-temperature and high-pressure gas will also produce an expansion refrigeration effect during the discharge process, and the hot end 5 of the cold head will be subjected to secondary heat absorption and cooling. Part of the absorbed heat is dissipated by natural convection along with the low-pressure helium through the length of the exhaust pipeline itself, and the remaining heat enters the compressor and is taken away by the heat exchanger 12 and the water cooling unit.

[0047] Figure 6A working cycle of the rotary valve corresponding to the small-hole gas reservoir bidirectional air intake pulse tube refrigerator with an additional heat dissipation device is given. In the FA process, the high-pressure recess 222 is first connected to the second peripheral through hole 212, and the auxiliary air intake valve V4 is opened. The low-temperature and high-pressure helium cooled by water cooling inside the compressor enters the heat dissipation pipeline 6. The cooled low-temperature and high-pressure helium conducts heat through the wall of the heat dissipation pipeline 6 to perform the first heat dissipation and cooling of the cold head hot end 5. In the AB process, the low-pressure recess 221 is connected to the first peripheral through hole 211, and the main exhaust valve V2 is opened. The high-pressure helium in the cold head expands and cools. During the discharge of the low-pressure and high-temperature helium after absorbing heat, the heat is transferred from the cold end to the cold head hot end 5, causing its temperature to rise. The BC process is a transition stage, and all main and auxiliary valves are in a closed state. In the CD process, the low-pressure recess 221 is connected to the second peripheral through hole 212, the auxiliary exhaust valve V3 is opened, and the high-pressure helium in the heat dissipation pipeline 6 is discharged to the low-pressure side, and expansion refrigeration occurs, which absorbs heat and cools down the heated hot end 5 of the cold head. The helium after absorbing heat and heating enters the exhaust pipe, is first compressed and heated in the compressor, and then cooled by water before entering the intake pipe. The DE process is a transition stage, and all main and auxiliary valves are in a closed state. In the EF process, the high-pressure recess 222 is connected to the first peripheral through hole 211, the main intake valve V2 is opened, and the high-pressure helium enters the cold head.

[0048] like Figure 7 As shown, as another implementation of the heat exchange structure, a heat dissipation cavity 62 is formed inside the hot end 5 of the cold head, and the heat dissipation cavity 62 has a heat dissipation cavity inlet and outlet 62a, and the heat dissipation cavity inlet and outlet 62a is connected to the auxiliary connecting pipe 24. In addition, fins 62b, micro-channels (not shown in the figure) and other structures can be added to the wall surface of the heat dissipation cavity 62 to enhance heat exchange.

[0049] The small stream of helium gas introduced directly purges the inner wall surface with fins at the hot end 5 of the cold head, which can greatly improve the heat exchange efficiency. The working process of the heat dissipation cavity 62 is the same as that of the heat dissipation pipeline 6. In the same cycle, the cooled high-pressure helium gas first enters through the auxiliary air inlet valve V4, absorbs heat with the wall surface of the hot end 5 of the cold head for the first time, and then becomes low-pressure helium gas during the degassing process, expands and cools, and absorbs heat with the wall surface of the hot end 5 of the cold head for the second time. Compared with the heat dissipation pipeline 6 coiled around the hot end 5 of the cold head, the heat dissipation cavity 62 has a larger heat exchange area, and the helium gas directly contacts the wall surface that needs to be dissipated. Therefore, the heat dissipation capacity is greater, and the corresponding processing difficulty is greater. Depending on the demand, it can be used for pulse tube refrigerators with larger cooling capacity.

[0050] The heat dissipation device and the rotary valve 2 mentioned above can be used not only for a small-hole gas reservoir bidirectional air inlet pulse tube refrigerator, but also for a four-valve pulse tube refrigerator.

[0051] In summary, the present invention proposes a rotary valve that realizes the periodic supply and exhaust functions of the cold head and the heat sink. The small stream of helium drawn out from the air supply pipeline is used as the cooling medium of the heat sink. The heat sink has a cycle process of cooling helium entering and discharging helium after absorbing heat and heating. The flow control device of the helium flow in the heat sink can adjust the flow rate of helium in the heat sink to realize the opening and closing of the heat sink and provide different heat dissipation powers. A small stream of cooled helium is drawn out from the air supply pipeline to the inside or surface of the hot end of the cold head through the rotary valve. During the residence time, the heat is transferred from the solid surface with a higher temperature at the hot end of the cold head to the helium with a lower temperature in the heat exchange device, and the hot end of the cold head is initially cooled and cooled. After the small stream of helium is drawn out and absorbs part of the heat, it is discharged to the low-pressure exhaust pipeline through the rotary valve in the subsequent time within a cycle. It expands and absorbs heat during the exhaust process, and the hot end of the cold head can be cooled and cooled again. After the heat enters the exhaust pipeline, part of it is dissipated by natural convection through the relatively long exhaust pipeline itself, and part of it returns to the compressor and is taken away by cold water in the heat exchanger through forced convection heat dissipation.

[0052] According to the technical solution of the present invention, the heat transfer and dissipation of the hot end of the cold head can be enhanced, the temperature of the hot end of the cold head can be reduced, and the cooling time can be shortened, the refrigeration performance can be improved, and the vibration can be reduced.

Claims

1. A heat dissipation device for the hot end of a pulse tube refrigerator cold head, characterized in that: The invention comprises an auxiliary valve group, wherein the auxiliary valve group comprises an auxiliary exhaust valve (V3) and an auxiliary intake valve (V4); a heat exchange structure is arranged on the hot end (5) of the cold head; the auxiliary intake valve (V4) is connected to the high-pressure pipeline (14) of the compressor; the auxiliary exhaust valve (V3) is connected to the low-pressure pipeline (13) of the compressor; and the auxiliary intake valve (V4) and the auxiliary exhaust valve (V3) are respectively connected to the heat exchange structure via an auxiliary connecting pipe (24); a flow control device (25) is arranged on the auxiliary connecting pipe (24); when the auxiliary intake valve (V4) is opened and the auxiliary exhaust valve (V3) is closed, A portion of the low-temperature and high-pressure helium formed by cooling the heat exchanger (12) enters the heat exchange structure through the auxiliary air intake valve (V4) and the auxiliary connecting pipe (24) to exchange heat with the cold head hot end (5) to cool it down, and the low-temperature and high-pressure helium absorbs heat to form high-temperature and high-pressure helium; the auxiliary exhaust valve (V3) is opened and the auxiliary air intake valve (V4) is closed, and the high-temperature and high-pressure helium enters the compressor low-pressure pipeline (13) through the auxiliary connecting pipe (24) and the auxiliary exhaust valve (V3); the flow control device (25) is used to control the helium flow according to the heating condition of the cold head hot end (5).

2. The heat dissipation device for the hot end of the cold head of a pulse tube refrigerator according to claim 1, characterized in that: The heat exchange structure comprises a heat dissipation pipeline (6), the heat dissipation pipeline (6) having a heat dissipation pipeline inlet and outlet (6a) for connecting to the auxiliary connecting pipe (24); the heat dissipation pipeline (6) is wound around the surface of the hot end (5) of the cold head.

3. The heat dissipation device for the hot end of the cold head of a pulse tube refrigerator according to claim 2, characterized in that: The surface of the hot end (5) of the cold head has a groove (5a) adapted to the heat dissipation pipeline (6), and the heat dissipation pipeline (6) is fixed in the groove (5a).

4. The heat dissipation device for the hot end of the cold head of a pulse tube refrigerator according to claim 1, characterized in that: The heat exchange structure comprises a heat dissipation cavity (62) formed inside the hot end (5) of the cold head, and the heat dissipation cavity (62) has a heat dissipation cavity inlet and outlet (62a) for connecting the auxiliary connecting pipe (24).

5. The heat dissipation device for the hot end of the cold head of a pulse tube refrigerator according to claim 4, characterized in that: The wall surface of the heat dissipation cavity (62) is provided with fins (62b) and micro flow channels for enhancing heat exchange.

6. The heat dissipation device for the hot end of the cold head of a pulse tube refrigerator according to claim 1, characterized in that: The flow control device (25) adopts a solenoid valve or a needle valve.

7. A pulse tube refrigerator, characterized in that: The heat dissipation device comprises a main valve group and any one of claims 1 to 6, wherein the main valve group comprises a main exhaust valve (V1) and a main intake valve (V2); the main exhaust valve (V1) is connected to a low-pressure pipeline (13) of a compressor, and the main intake valve (V2) is connected to a high-pressure pipeline (14) of the compressor, and the main exhaust valve (V1) and the main intake valve (V2) are connected to a cold head (3) via a main connecting pipe (23), respectively; the main intake valve (V2) is opened and the main exhaust valve (V1) is closed to realize the intake process of the cold head (3); the main exhaust valve (V1) is opened and the main intake valve (V2) is closed to realize the exhaust process of the cold head (3).

8. The pulse tube refrigerator according to claim 7, characterized in that The functions of the main exhaust valve (V1), the main intake valve (V2), the auxiliary exhaust valve (V3) and the auxiliary intake valve (V4) are realized by a rotary valve (2).

9. The pulse tube refrigerator according to claim 8, characterized in that The rotary valve (2) comprises a valve stator (21) and a valve rotor (22); the valve rotor (22) has a high-pressure recess (222) at the center and a low-pressure recess (221) around it; the valve stator (21) has a central through hole (213) at the center and has a first peripheral through hole (211) connected to the cold head (3) and a second peripheral through hole (212) connected to the heat exchange structure around it; the high-pressure recess (222) is always connected to the compressor high-pressure pipeline (14) through the central through hole (213); the low-pressure recess (221) is always connected to the compressor low-pressure pipeline (13) through a cover body or a motor low-pressure chamber; the valve rotor (22) rotates periodically, so that the high-pressure recess (222) and the low-pressure recess (221) are alternately connected or disconnected with the first peripheral through hole (211) and the second peripheral through hole (212) of the valve stator (21), thereby realizing the opening and closing functions of the main valve group and the auxiliary valve group.

10. The pulse tube refrigerator according to any one of claims 7 to 9, characterized in that: The pulse tube refrigerator includes a small-hole gas reservoir bidirectional air inlet pulse tube refrigerator and a four-valve pulse tube refrigerator.

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