Two-stage thermally coupled pulse tube refrigerator

Abstract

This disclosure relates to the field of cryogenic refrigeration technology, and more particularly to a two-stage thermally coupled pulse tube refrigeration machine. This two-stage thermally coupled pulse tube refrigeration machine includes a primary refrigeration mechanism comprising a primary accumulator and a primary cold-end heat exchanger; and a secondary refrigeration mechanism comprising a secondary compressor, a secondary precooling pipe, and a secondary accumulator, wherein a precooling channel is formed between the inner wall of the secondary precooling pipe and the outer wall of the primary accumulator. This disclosure utilizes the precooling channel formed between the inner wall of the secondary precooling pipe and the outer wall of the primary accumulator, allowing heat exchange between the gas entering the secondary accumulator from the secondary compressor and the outer wall of the primary accumulator within the channel, thus achieving precooling. This disclosure replaces the transitional accumulator with a secondary precooling pipe on the outside of the primary accumulator, making the overall structure more compact; simultaneously, it effectively utilizes the temperature gradient outside the cold end, reducing flow resistance loss, optimizing phase, and improving the efficiency of the refrigeration machine.

Description

Technical Field

[0001] This disclosure relates to the field of cryogenic refrigeration technology, and in particular to a two-stage thermally coupled pulse tube refrigeration machine. Background Technology

[0002] Stirling tube cryogenerators are widely used in space, military, and other fields to provide cryogenic environments for detectors due to their advantages such as no moving parts at the cold end, reliable operation, small size, and light weight. As the requirements for detectors in fields such as space exploration increase, many detectors now need to operate in temperatures below 20K. However, existing single-stage pulse tube cryogenerators have limited cooling capacity and cannot reach temperatures below 20K.

[0003] In traditional thermally coupled two-stage pulse tube refrigerators, the second-stage compressor operates at room temperature. A significant temperature gradient exists between the gas exiting the second-stage compressor and the second-stage accumulator. Directly connecting the second-stage compressor and accumulator degrades the refrigerator's performance. Therefore, a transition accumulator is typically introduced between the second-stage compressor and the second-stage accumulator to mitigate the impact of this excessive temperature gradient. However, the introduction of the transition accumulator increases gas flow resistance and alters the internal impedance of the second-stage pulse tube's cooling fingers, increasing the difficulty of phase adjustment and consequently affecting the overall performance of the refrigerator. Furthermore, placing the transition accumulator alongside the first-stage cooling fingers increases the structural dimensions of the cooling fingers, making it unsuitable for practical applications. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, this disclosure provides a two-stage thermally coupled pulse tube refrigerator.

[0005] This disclosure provides a two-stage thermally coupled pulse tube refrigerator, including:

[0006] The primary refrigeration mechanism includes a primary compressor, a primary hot-end heat exchanger, a primary cold accumulator, a primary cold-end heat exchanger, a primary pulse tube, a primary inertial tube, and a primary gas storage unit.

[0007] The secondary refrigeration mechanism includes a secondary compressor, a secondary precooling pipe, a secondary cold accumulator, a secondary pulse tube, a secondary cold-end heat exchanger, a secondary inertial tube, and a secondary gas storage. The secondary precooling pipe is connected to the secondary compressor and the secondary cold accumulator respectively. The precooling pipe is sleeved on the outside of the primary cold accumulator, and a precooling channel is formed between the inner wall of the secondary precooling pipe and the outer wall of the primary cold accumulator.

[0008] Optionally, the primary refrigeration mechanism includes a primary refrigeration platform, which includes a primary cold-end heat exchanger and a secondary cold accumulator outlet gas flow channel disposed outside the primary cold-end heat exchanger. The primary cold-end heat exchanger is connected to the primary cold accumulator, and the secondary cold accumulator outlet gas flow channel is connected to the precooling channel.

[0009] Optionally, the primary cooling platform is located between the precooling channel and the secondary cold accumulator, and the precooling channel is connected to the secondary cold accumulator through the outlet gas flow channel of the secondary cold accumulator.

[0010] Optionally, the secondary refrigeration mechanism further includes a secondary cold end heat exchanger, which is located at the end of the secondary cold accumulator away from the secondary precooling pipe and is connected to the secondary cold accumulator.

[0011] Optionally, the secondary refrigeration mechanism further includes a secondary pulse tube, which is connected to the cold end heat exchanger of the secondary accumulator, and the secondary accumulator is sleeved on the outside of the secondary pulse tube.

[0012] Optionally, the secondary refrigeration mechanism further includes a secondary pulse tube and a secondary pulse tube hot-end heat exchanger, wherein the secondary pulse tube and the secondary pulse tube hot-end heat exchanger are sequentially arranged at the end of the secondary cold accumulator away from the secondary precooling pipe.

[0013] Optionally, the secondary refrigeration mechanism further includes a secondary pulse tube cold-end heat exchanger and a secondary pulse tube cold-end flow channel, wherein the secondary pulse tube cold-end flow channel is used to connect the secondary pulse tube cold-end heat exchanger and the secondary accumulator cold-end heat exchanger.

[0014] Optionally, a secondary pulse tube and a secondary pulse tube hot-end heat exchanger are sequentially arranged at the end of the secondary pulse tube cold-end heat exchanger away from the secondary pulse tube cold-end flow channel.

[0015] Optionally, the secondary refrigeration mechanism further includes a secondary inertial tube and a secondary gas reservoir. The secondary inertial tube is used to connect the secondary pulse tube and the secondary gas reservoir, and the secondary inertial tube is wound around the outside of the secondary precooling pipe.

[0016] Optionally, the secondary refrigeration mechanism further includes a secondary inertial tube and a secondary gas storage tank, the primary refrigeration platform includes a primary cold-end thermal bridge, the secondary inertial tube and the secondary gas storage tank are disposed on the primary cold-end thermal bridge, and the secondary inertial tube is connected to the secondary pulse tube.

[0017] Optionally, the inner surface of the secondary precooling pipe is provided with a porous media material.

[0018] Optionally, it also includes a three-stage refrigeration mechanism, which includes a three-stage pre-cooling pipe, which is sleeved on the outside of the two-stage cold storage unit (10).

[0019] The technical solution provided in this disclosure has the following advantages compared with the prior art:

[0020] This disclosure utilizes the cooling capacity outside the primary accumulator to precool the gas in the secondary transition section. By fitting a precooling pipe from the secondary refrigeration mechanism outside the primary accumulator, a precooling channel is formed between the inner wall of the precooling pipe and the outer wall of the primary accumulator. This channel connects the outlet of the secondary compressor to the inlet of the secondary accumulator. As the gas enters the secondary accumulator from the secondary compressor, heat exchange occurs between the gas and the outer wall of the primary accumulator within the channel, achieving precooling. This structure effectively utilizes the temperature gradient outside the primary accumulator to precool the gas entering the secondary accumulator. By replacing the transition accumulator with a secondary precooling pipe outside the primary accumulator, the overall structure of this device becomes more compact. Simultaneously, the effective utilization of the temperature gradient outside the accumulator reduces flow resistance losses, optimizes phase, and improves the efficiency of the refrigeration unit. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0022] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the first structure of the two-stage thermally coupled pulse tube refrigerator according to the embodiments of this disclosure;

[0024] Figure 2 This is a schematic diagram of the second structure of the two-stage thermally coupled pulse tube refrigerator described in the embodiments of this disclosure;

[0025] Figure 3 This is a schematic diagram of the third structure of the two-stage thermally coupled pulse tube refrigerator described in the embodiments of this disclosure;

[0026] Figure 4 This is a schematic diagram of the fourth structure of the two-stage thermally coupled pulse tube refrigerator described in the embodiments of this disclosure;

[0027] Figure 5 This is a schematic diagram of the fifth structure of the two-stage thermally coupled pulse tube refrigerator described in the embodiments of this disclosure;

[0028] Figure 6 This is a schematic diagram of the sixth structure of the two-stage thermally coupled pulse tube refrigerator described in the embodiments of this disclosure.

[0029] Among them, 1-first stage compressor; 2-first stage hot end heat exchange platform; 201-first stage hot end heat exchanger; 202-second stage compressor outlet gas flow channel; 203-first stage hot end flange; 3-first stage accumulator; 4-first stage cold platform; 401-first stage cold end heat exchanger; 402-second stage accumulator outlet gas flow channel; 403-first stage cold end thermal bridge; 5-first stage pulse tube; 6-first stage inertia tube; 7-first stage gas storage; 8-second stage compressor; 9-precooling channel; 10-second stage accumulator; 11-second stage accumulator cold end heat exchanger; 12-second stage pulse tube cold end flow channel; 13-second stage pulse tube cold end heat exchanger; 14-second stage pulse tube; 15-second stage pulse tube hot end heat exchanger; 16-second stage inertia tube; 17-second stage gas storage. Detailed Implementation

[0030] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0031] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0032] This disclosure provides a two-stage thermally coupled pulse tube refrigerator, comprising:

[0033] The primary refrigeration mechanism includes a primary compressor 1, a primary hot-end heat exchanger 201, a primary cold-end heat accumulator 3, a primary cold-end heat exchanger 401, a primary pulse tube 5, a primary inertial tube 6, and a primary gas storage 7.

[0034] The secondary refrigeration mechanism includes a secondary compressor 8, a secondary precooling pipe, a secondary accumulator 10, a secondary cold-end heat exchanger 11, a secondary pulse tube 14, a secondary inertial tube 16, and a secondary gas storage 17. The secondary precooling pipe is connected to the secondary compressor 8 and the secondary accumulator 10 respectively. The precooling pipe is sleeved on the outside of the primary accumulator 3, and a precooling channel 9 is formed between the inner wall of the precooling pipe and the outer wall of the primary accumulator 3.

[0035] In this embodiment, the transitional cold accumulator of the secondary refrigeration mechanism is eliminated. Instead, a precooling pipe in the secondary refrigeration mechanism is fitted outside the primary cold accumulator 3, forming a precooling channel 9 between the inner wall of the precooling pipe and the outer wall of the primary cold accumulator 3. This precooling channel connects the outlet of the secondary compressor 8 and the inlet of the secondary cold accumulator 10. As the gas enters the secondary cold accumulator 10 from the secondary compressor 8, it exchanges heat with the outer wall of the primary cold accumulator 3 within the channel, achieving precooling. This structure, by replacing the transitional cold accumulator with a secondary precooling pipe outside the primary cold accumulator, makes the overall structure more compact. Simultaneously, it effectively utilizes the temperature gradient outside the cold finger, reducing flow resistance loss, optimizing phase, and improving the efficiency of the refrigeration unit.

[0036] Based on the above-mentioned secondary precooling pipe being sleeved on the outside of the primary cold accumulator 3 so that a precooling channel 9 is formed between the inner wall of the secondary precooling pipe and the outer wall of the primary cold accumulator 3, this disclosure has the following six embodiments:

[0037] Example 1

[0038] like Figure 1 As shown, in this refrigeration unit, the gas discharged from the outlet of the first-stage compressor 1 is connected to the gas in the first-stage cold accumulator 3 via the first-stage hot-end heat exchanger 201 in the first-stage hot-end heat exchange platform 2. The first-stage cold accumulator 3 is connected to the first-stage pulse tube 5 via the first-stage cold-end heat exchanger 401 in the first-stage cold platform 4. The first-stage pulse tube 5 is connected to the first-stage inertial tube 6, and the first-stage inertial tube 6 is connected to the first-stage gas storage 7. The second-stage refrigeration mechanism adopts a coaxial structure. The gas from the outlet of the second-stage compressor 8 passes through the second-stage compressor outlet gas flow channel 202 in the first-stage hot-end heat exchange platform 2, first passes through the pre-cooling channel 9, and then passes through the second-stage cold accumulator 10 outlet gas flow channel 402 in the first-stage cold platform 4, connecting to the second-stage cold accumulator 10. The second-stage cold accumulator 10, the second-stage cold-end heat exchanger 11, and the second-stage pulse tube 14 are connected in sequence. The second-stage pulse tube 14 is connected to the second-stage inertial tube 16, and the second-stage inertial tube 16 is wound around the outside of the gas heat exchange slit of the second-stage refrigeration mechanism and connected to the second-stage gas storage 17.

[0039] Example 2

[0040] like Figure 2As shown, in this refrigeration unit, the gas discharged from the outlet of the first-stage compressor 1 is connected to the gas in the first-stage cold accumulator 3 via the first-stage hot-end heat exchanger 201 in the first-stage hot-end heat exchange platform 2. The first-stage cold accumulator 3 is connected to the first-stage pulse tube 5 via the first-stage cold-end heat exchanger 401 in the first-stage cold platform 4. The first-stage pulse tube 5 is connected to the first-stage inertial tube 6, and the first-stage inertial tube 6 is connected to the first-stage gas storage 7. The second-stage refrigeration mechanism adopts a linear structure. The gas from the outlet of the second-stage compressor 8 first passes through the second-stage compressor outlet gas flow channel 202 in the first-stage hot-end heat exchange platform, passes through the pre-cooling channel 9, and is connected to the second-stage cold accumulator 10 via the outlet gas flow channel 402 in the first-stage cold platform 4. The second-stage cold accumulator 10, the second-stage cold-end heat exchanger 11, the second-stage pulse tube 14, and the second-stage pulse tube hot-end heat exchanger 15 are connected in sequence. The secondary pulse tube 14 is connected to the secondary inertial tube 16 through the secondary pulse tube hot end heat exchanger 15. The secondary inertial tube 16 is wound around the outside of the gas heat exchange slit of the secondary refrigeration mechanism, passes through the primary hot end heat exchange platform 2 and is connected to the secondary gas storage 17.

[0041] Example 3

[0042] like Figure 3 As shown, in this refrigeration unit, the gas discharged from the outlet of the first-stage compressor 1 is connected to the gas in the first-stage cold accumulator 3 via the first-stage hot-end heat exchanger 201 in the first-stage hot-end heat exchange platform 2. The first-stage cold accumulator 3 is connected to the first-stage pulse tube 5 via the first-stage cold-end heat exchanger 401 in the first-stage cold platform 4. The first-stage pulse tube 5 is connected to the first-stage inertial tube 6, and the first-stage inertial tube 6 is connected to the first-stage gas storage 7. The second-stage refrigeration mechanism adopts a U-shaped structure, and the second-stage pulse tube hot-end heat exchanger 15 is connected to the first-stage cold-end thermal bridge 403. The gas from the outlet of the second-stage compressor 8 first passes through the second-stage compressor outlet gas flow channel 202 in the first-stage cold-end heat exchange platform, passes through the gas heat exchange slit of the second-stage refrigeration mechanism, and then passes through the outlet gas flow channel 402 of the second-stage cold accumulator 10 in the first-stage cold platform 4 to connect with the second-stage cold accumulator 10. The secondary cold accumulator 10, the secondary cold accumulator cold-end heat exchanger 11, the secondary pulse tube 14 cold-end flow channel 12, the secondary pulse tube 14 cold-end heat exchanger 13, the secondary pulse tube 14, and the secondary pulse tube hot-end heat exchanger 15 are connected in sequence. The secondary pulse tube hot-end heat exchanger 15 is connected to the secondary inertial tube 16, which is wound around the outside of the gas heat exchange slit of the secondary refrigeration mechanism, passes through the primary hot-end heat exchange platform 2, and is connected to the secondary gas storage 17.

[0043] like Figures 1 to 3 In the two-stage thermally coupled pulse tube refrigerator shown, the gas reservoir in the phase-adjusting mechanism of the second-stage refrigeration unit is placed on the room temperature side, while the inertial tube is wound around the outside of the gas heat exchange slit of the second-stage refrigeration unit. This structure can reduce the heat exchange loss caused by the inertial tube. At the same time, because the gas reservoir in this structure is placed on the room temperature side, it is not necessary to increase the area of ​​the first-stage cold-end heat exchanger 401 to accommodate the phase-adjusting mechanism, making the refrigerator structure more compact. Figures 1 to 3 The primary hot-end heat exchange platform 2 includes a primary hot-end heat exchanger 201, a secondary compressor outlet gas flow channel 202, and a primary hot-end heat exchanger 203. Figure 1 and Figure 2 The primary cold platform 4 includes a primary cold-end heat exchanger 401 and a secondary cold accumulator inlet gas flow channel 402. Figure 3 The primary cold platform 4 includes a primary cold-end heat exchanger 401, a secondary cold accumulator 10 inlet gas flow channel, and a primary cold-end thermal bridge 403.

[0044] Example 4

[0045] like Figure 4 As shown, in this refrigeration unit, the gas discharged from the outlet of the first-stage compressor 1 is connected to the gas in the first-stage cold accumulator 3 via the first-stage hot-end heat exchanger 201 in the first-stage hot-end heat exchange platform 2. The first-stage cold accumulator 3 is connected to the first-stage pulse tube 5. The first-stage pulse tube 5 is connected to the first-stage inertial tube 6, and the first-stage inertial tube 6 is connected to the first-stage gas storage 7. The second-stage refrigeration mechanism adopts a coaxial structure. The gas from the outlet of the second-stage compressor 8 first passes through the second-stage compressor outlet gas flow channel 202 in the first-stage hot-end heat exchange platform, passes through the pre-cooling channel 9, and then passes through the outlet gas flow channel 402 of the second-stage cold accumulator 10 in the first-stage cold platform 4, connecting to the second-stage cold accumulator 10. The second-stage cold accumulator 10, the second-stage cold-end heat exchanger, and the second-stage pulse tube 14 are connected in sequence. The second-stage pulse tube 14 is connected to the second-stage inertial tube 16, the second-stage inertial tube 16 is connected to the second-stage gas storage 17, and both the second-stage inertial tube 16 and the second-stage gas storage 17 are connected to the first-stage cold platform 4.

[0046] Example 5

[0047] like Figure 5 As shown, in this refrigeration unit, the gas discharged from the outlet of the first-stage compressor 1 is connected to the gas in the first-stage cold accumulator 3 via the first-stage hot-end heat exchanger 201 in the first-stage hot-end heat exchange platform 2. The first-stage cold accumulator 3 is connected to the first-stage pulse tube 5. The gas in the first-stage pulse tube 5 is connected to the first-stage inertial tube 6 via the gas flow channel in the first-stage hot-end heat exchange platform 2, and the first-stage inertial tube 6 is connected to the first-stage gas storage 7. The second-stage refrigeration mechanism adopts a linear structure. The gas from the outlet of the second-stage compressor 8 first passes through the second-stage compressor outlet gas flow channel 202 in the first-stage hot-end heat exchange platform, passes through the pre-cooling channel 9, and then passes through the second-stage cold accumulator 10 outlet gas flow channel 402 in the first-stage cold platform 4 to connect with the second-stage cold accumulator 10. The second-stage cold accumulator 10, the second-stage cold-end heat exchanger, the second-stage pulse tube 14, and the second-stage pulse tube hot-end heat exchanger 15 are connected in sequence. The secondary pulse tube hot end heat exchanger 15 is connected to the secondary inertial tube 16, the secondary inertial tube 16 is connected to the secondary gas storage 17, and both the secondary inertial tube 16 and the secondary gas storage 17 are connected to the primary cold platform 4.

[0048] Example 6

[0049] like Figure 6 As shown, in this refrigeration unit, the gas discharged from the outlet of the first-stage compressor 1 is connected to the gas in the first-stage cold accumulator 3 via the first-stage hot-end heat exchanger 201 in the first-stage hot-end heat exchange platform 2. The first-stage cold accumulator 3 is connected to the first-stage pulse tube 5. The first-stage pulse tube 5 is connected to the first-stage inertial tube 6, and the first-stage inertial tube 6 is connected to the first-stage gas storage 7. The second-stage refrigeration mechanism adopts a U-shaped structure. The gas from the outlet of the second-stage compressor 8 first passes through the second-stage compressor outlet gas flow channel 202 in the first-stage hot-end heat exchange platform, passes through the pre-cooling channel 9, and then passes through the outlet gas flow channel 402 of the second-stage cold accumulator 10 in the first-stage cold platform 4, connecting to the second-stage cold accumulator 10. The second-stage cold accumulator 10, the second-stage cold accumulator cold-end heat exchanger 11, the second-stage pulse tube 14 cold-end flow channel 12, the second-stage pulse tube 14 cold-end heat exchanger 13, the second-stage pulse tube 14, and the second-stage pulse tube hot-end heat exchanger 15 are connected in sequence. The secondary pulse tube hot end heat exchanger 15 is connected to the secondary inertial tube 16, the secondary inertial tube 16 is connected to the secondary gas storage 17, and both the secondary inertial tube 16 and the secondary gas storage 17 are connected to the primary cold platform 4.

[0050] like Figures 4 to 6 In the three embodiments shown, the phase adjustment mechanism adopts a combination of a low-temperature inertial tube and a low-temperature gas reservoir. The phase adjustment mechanism is placed on the primary cold-end thermal bridge 403, utilizing the cooling capacity of the primary cold-end heat exchanger 401, reducing the heat exchange loss of the phase adjustment mechanism, and improving the performance of the refrigerator.

[0051] This disclosure describes a thermally coupled two-stage pulse tube refrigerator, wherein the cold end heat exchanger of the first-stage pulse tube 5 cold finger serves as the hot end heat exchanger of the second-stage pulse tube 14 cold finger, providing pre-cooling conditions for the second-stage pulse tube 14 cold finger, and the gas between the two stages of cold fingers is not interconnected.

[0052] Furthermore, the secondary precooling piping is coaxially arranged with the primary accumulator 3, resulting in a compact overall structure. The secondary refrigeration mechanism can adopt a coaxial, linear, or U-shaped structure. The phase adjustment method of the secondary refrigeration mechanism can be a combination of a room temperature side gas reservoir and an inertial tube wound around the outside of the gas heat exchange slit of the secondary refrigeration mechanism, or a combination of a low temperature gas reservoir and a low temperature inertial tube.

[0053] The secondary refrigeration mechanism in this embodiment is also applicable to pulse tube refrigerators that use other phase adjustment methods, including but not limited to bidirectional air intake type, multi-way bypass type, and small-hole air chamber type.

[0054] In some embodiments, the inner surface of the secondary precooling pipe may be provided with a porous media material and slits may be provided to enhance the flow guiding effect.

[0055] In some embodiments, a three-stage refrigeration mechanism is also included, which includes a three-stage precooling pipe that is sleeved on the outside of the two-stage accumulator 10.

[0056] In other words, this device can be configured as a three-stage refrigeration unit, and similarly, it can also be applied to multi-stage pulse tube refrigeration units.

[0057] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A two-stage thermally coupled pulse tube refrigerator, characterized in that, include: The primary refrigeration mechanism includes a primary compressor (1), a primary hot-end heat exchanger (201), a primary cold accumulator (3), a primary cold-end heat exchanger (401), a primary pulse tube (5), a primary inertial tube (6), and a primary gas storage (7). The secondary refrigeration mechanism includes a secondary compressor (8), a secondary precooling pipe and a secondary accumulator (10), a cold end heat exchanger (11) of the secondary accumulator, a secondary pulse tube (14), a secondary inertial tube (16) and a secondary gas reservoir (17). The two ends of the secondary precooling pipe are connected to the secondary compressor (8) and the secondary accumulator (10) respectively. The secondary precooling pipe is sleeved on the outside of the primary accumulator (3), and a precooling channel (9) is formed between the inner wall of the secondary precooling pipe and the outer wall of the primary accumulator (3).

2. The two-stage thermally coupled pulse tube refrigerator according to claim 1, characterized in that, The primary refrigeration mechanism includes a primary refrigeration platform (4), which includes the primary cold end heat exchanger (401) and a secondary cold accumulator outlet gas flow channel (402) located outside the primary cold end heat exchanger (401). The primary cold end heat exchanger is connected to the primary cold accumulator (3), and the secondary cold accumulator outlet gas flow channel (402) is connected to the precooling channel (9).

3. The two-stage thermally coupled pulse tube refrigerator according to claim 2, characterized in that, The primary cooling platform (4) is located between the precooling channel (9) and the secondary cold storage unit (10). The precooling channel (9) is connected to the secondary cold storage unit (10) through the outlet gas flow channel (402) of the secondary cold storage unit.

4. The two-stage thermally coupled pulse tube refrigerator according to claim 2, characterized in that, The cold end heat exchanger (11) of the secondary cold accumulator is located at one end of the secondary cold accumulator (10) away from the secondary precooling pipe and is connected to the secondary cold accumulator (10).

5. The two-stage thermally coupled pulse tube refrigerator according to claim 4, characterized in that, The secondary pulse tube (14) is connected to the cold end heat exchanger (11) of the secondary accumulator, and the secondary accumulator (10) is sleeved on the outside of the secondary pulse tube (14).

6. The two-stage thermally coupled pulse tube refrigerator according to claim 4, characterized in that, The secondary refrigeration mechanism also includes a secondary pulse tube hot end heat exchanger (15), wherein the secondary pulse tube (14) and the secondary pulse tube hot end heat exchanger (15) are sequentially arranged at the end of the secondary cold storage (10) away from the secondary precooling pipe.

7. The two-stage thermally coupled pulse tube refrigerator according to claim 4, characterized in that, The secondary refrigeration mechanism further includes a secondary pulse tube cold end heat exchanger (13) and a secondary pulse tube cold end flow channel (12), the secondary pulse tube cold end flow channel (12) being used to connect the secondary pulse tube cold end heat exchanger (13) and the secondary accumulator cold end heat exchanger (11).

8. The two-stage thermally coupled pulse tube refrigerator according to claim 7, characterized in that, The secondary pulse tube cold end heat exchanger (13) is provided with a secondary pulse tube (14) and a secondary pulse tube hot end heat exchanger (15) in sequence at the end away from the secondary pulse tube cold end flow channel (12).

9. The two-stage thermally coupled pulse tube refrigerator according to any one of claims 5 to 8, characterized in that, The secondary refrigeration mechanism also includes a secondary inertial tube (16) and a secondary gas reservoir (17). The secondary inertial tube (16) is used to connect the secondary pulse tube (14) and the secondary gas reservoir (17). The secondary inertial tube (16) is wrapped around the outside of the secondary precooling pipe.

10. The two-stage thermally coupled pulse tube refrigerator according to any one of claims 5 to 8, characterized in that, The secondary refrigeration mechanism also includes a secondary inertial tube (16) and a secondary gas storage (17). The primary refrigeration platform (4) includes a primary cold end thermal bridge (403). The secondary inertial tube (16) and the secondary gas storage (17) are arranged on the primary cold end thermal bridge (403). The secondary inertial tube (16) is connected to the secondary pulse tube (14).

11. The two-stage thermally coupled pulse tube refrigerator according to claim 1, characterized in that, The inner surface of the secondary precooling pipe is provided with a porous media material.

12. The two-stage thermally coupled pulse tube refrigerator according to claim 1, characterized in that, It also includes a three-stage refrigeration mechanism, which includes a three-stage pre-cooling pipe, which is sleeved on the outside of the two-stage cold storage unit (10).

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