A coaxial thermally coupled pulse tube refrigerator

Abstract

This invention relates to a coaxial thermally coupled pulse tube refrigerator, comprising a compressor, a multi-stage cold head, and a phase-adjusting mechanism. The multi-stage cold heads are thermally coupled and coaxially arranged, with the pulse tubes of the high-temperature stage and the regenerator placed outside the low-temperature stage, respectively. Compared with the prior art, this invention has a compact structure and high reliability.

Description

Technical Field

[0001] This invention relates to refrigeration machines, and more particularly to a coaxial thermally coupled pulse tube refrigeration machine. Background Technology

[0002] In recent years, with the rapid development of key fields such as aerospace, the demand for cryogenic environments has been increasing, a trend that has greatly promoted the rapid development of small cryogenic refrigerator technology. In diverse application scenarios, the requirements for the reliability, lifespan, and weight of refrigerators are gradually increasing. Especially in the field of deep space exploration, even more stringent standards have been set for the performance of refrigerators.

[0003] Deep space probes often need to operate for extended periods in extreme space environments, requiring cryogenic refrigerators to not only possess highly efficient cooling capabilities but also ensure extremely high reliability and a long service life. Furthermore, considering the stringent weight and space constraints of the probes, the size and weight of the cryogenic refrigerators must be minimized as much as possible. Therefore, developing a compact, high-performance miniature cryogenic refrigerator is crucial for advancing deep space exploration technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art and provide a coaxial thermally coupled pulse tube refrigerator with a simplified structure and high reliability, which can achieve efficient cooling in the 20K temperature range.

[0005] The objective of this invention can be achieved through the following technical solution: a coaxial thermally coupled pulse tube refrigerator, comprising a compressor, a multi-stage cold head and a phase adjustment mechanism, wherein the multi-stage cold head is thermally coupled and coaxially arranged to form a layered encapsulation structure.

[0006] Furthermore, the cold head is configured with n stages, where n≥2. From the center outwards, the refrigeration unit consists of the nth stage pulse tube, the (n-1)th stage pulse tube, ..., the 1st stage pulse tube, the 1st stage regenerator, ..., the (n-1)th stage regenerator, and the nth stage regenerator, forming a layered coaxial structure.

[0007] Furthermore, the cold head is configured with n stages, where n≥2. From the center outwards, the refrigeration unit consists of the nth stage pulse tube, the nth stage regenerator, the (n-1)th stage pulse tube, the (n-1)th stage regenerator, ..., the 1st stage pulse tube, and the 1st stage regenerator.

[0008] Furthermore, the multi-stage cold head is driven by a single linear compressor, or by multiple linear compressors, or by a stepped piston compressor, or by a combination of linear compressors and stepped piston compressors.

[0009] Furthermore, each stage of the cold head is composed of a water cooler, a regenerator, a cold end heat exchanger, and a pulse tube connected in sequence.

[0010] Furthermore, each level of the cold head uses the same inertial tube and gas reservoir, or separate inertial tubes and gas reservoirs, as the phase adjustment mechanism.

[0011] Furthermore, each stage of the cold head uses a stepped push piston or a stepped piston as the phase adjustment mechanism.

[0012] Furthermore, thermal coupling occurs between the various levels of the cold heads.

[0013] Furthermore, the cold head is set in two stages: from the center outwards, the cold head consists of a low-temperature pulse tube, a high-temperature pulse tube, a high-temperature regenerator, and a low-temperature regenerator.

[0014] Furthermore, the cold head is set in two stages: from the center outwards, the cold head consists of a low-temperature pulse tube, a low-temperature regenerator, a high-temperature pulse tube, and a high-temperature regenerator.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The coaxial thermally coupled pulse tube refrigerator of the present invention adopts a coaxial arrangement among its multiple stages. The pulse tube and regenerator of the high-temperature stage are placed on the outside of the low-temperature stage, which has a compact structure and high reliability. It is particularly suitable for applications with high requirements for refrigerator quality, such as deep space exploration.

[0017] 2. The phase adjustment mechanism of this invention can be a series of separate inertial tubes and gas reservoirs, a common inertial tube phase adjustment mechanism (i.e., the pulse hot end of the multi-stage cold head is connected to the same inertial tube and gas reservoir), or a stepped push piston (i.e., the pulse hot end of the multi-stage cold head is connected to different expansion chambers of the stepped push piston). This further reduces the number of components, weight, and volume, while achieving the same cooling effect.

[0018] 4. The compressor described in this invention is one or a combination of several types, including multi-stage stepped piston compressors and linear compressors. The compressor may be a single multi-stage stepped piston compressor, or multiple linear compressors; or a single linear compressor. Attached Figure Description

[0019] Figure 1 This refers to the coaxial thermally coupled two-stage pulse tube refrigerator of Example 1;

[0020] Figure 2 This refers to the coaxial thermally coupled two-stage pulse tube refrigerator of Example 2;

[0021] Figure 3 This refers to the coaxial thermally coupled two-stage pulse tube refrigerator of Example 3;

[0022] Figure 4 This is the coaxial thermally coupled two-stage pulse tube refrigerator of Example 4;

[0023] Figure 5 This refers to the coaxial thermally coupled two-stage pulse tube refrigerator of Example 5;

[0024] Figure 6 This refers to the coaxial thermally coupled two-stage pulse tube refrigerator of Example 6;

[0025] Figure 7 This refers to the coaxial thermally coupled two-stage pulse tube refrigerator of Example 7;

[0026] Figure 8 This refers to the coaxial thermally coupled three-stage pulse tube refrigerator of Example 8;

[0027] Figure 9 This is the coaxial thermally coupled three-stage pulse tube refrigerator of Example 9. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0029] Example 1

[0030] like Figure 1 As shown, a coaxial thermally coupled two-stage pulse tube refrigerator includes a compression mechanism 1, a multi-stage cold head, and a phase-adjusting mechanism. In this embodiment, the multi-stage cold head is two-stage, and each stage includes a water cooler, a regenerator, a low-temperature end heat exchanger, and a pulse tube. Specifically, as shown... Figure 1 The first-stage cold head includes: a first-stage water cooler 21-1, a first-stage regenerator 22-1, a first-stage low-temperature end heat exchanger 23-1, and a first-stage pulse tube 24-1 connected in sequence; the second-stage cold head includes: a second-stage water cooler 21-2, a second-stage regenerator 22-2, a second-stage low-temperature end heat exchanger 23-2, and a second-stage pulse tube 24-2 connected in sequence; the phase adjustment mechanism includes a first-stage phase adjustment mechanism 3-1 and a second-stage phase adjustment mechanism 3-2.

[0031] The two-stage cold heads are arranged coaxially: from the inside out, they are the second-stage pulse tube 24-2, the first-stage pulse tube 24-1, the first-stage regenerator 22-1, and the second-stage regenerator 22-2. Specifically, the second-stage pulse tube 24-2 is located in the center, with the first-stage pulse tube 24-1, the first-stage regenerator 22-1, and the second-stage regenerator 22-2 arranged coaxially outwards, forming a layered structure. The first-stage water cooler 21-1 and the first-stage low-temperature heat exchanger 23-1 are located at opposite ends of the first-stage regenerator 22-1, and the second-stage water cooler 21-2 and the second-stage low-temperature heat exchanger 23-2 are located at opposite ends of the second-stage regenerator 22-2.

[0032] A linear compressor 1 is connected to a water-cooled unit with two cold heads, and power distribution is performed at the compressor outlet. The hot ends of the pulse tubes of the two cold heads are respectively connected to two inertial tubes as phase adjustment mechanisms.

[0033] The two-stage pulse tube refrigerator is filled with a high-pressure working fluid. Compressor 1 drives the cold head of the pulse tube refrigerator, thereby producing a cooling effect.

[0034] After near-adiabatic compression of the working fluid inside compressor 1, it enters the two-stage cold heads, where it is cooled to room temperature in its respective water coolers, and then further cooled to a low temperature by passing through a regenerator. The working fluid absorbs heat from the outside in the low-temperature heat exchanger, generating cooling capacity, and then expands in the pulse tubes. The phase-adjusting mechanism adjusts the phase of the mass flow and pressure wave inside the pulse tube refrigerator, ensuring they are in phase at the midpoint of the regenerator, thereby minimizing regenerator losses.

[0035] Example 2

[0036] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 2 As shown, the difference from Embodiment 1 is that the two-stage pulse tube refrigerator's two cold heads are driven by two separate linear compressors. Compressor 11 is connected to the water cooler of the first cold head, and compressor 12 is connected to the water cooler of the second cold head. Compared to Embodiment 1, this design has a more complex compressor structure, but the two-stage refrigerator can operate at different frequencies, charging pressures, and input power, allowing for convenient adjustment of the refrigerator's parameters to achieve better cooling efficiency and greater cooling capacity.

[0037] Example 3

[0038] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 3 As shown, the difference from Embodiment 1 is that the two-stage cold heads of this two-stage pulse tube refrigerator are respectively connected to the two compression chambers of a stepped piston compressor. In this embodiment, the first-stage cold head is connected to the first-stage compression chamber of the stepped piston compressor, and the second-stage cold head is connected to the second-stage compression chamber of the stepped piston compressor. Compared with Embodiment 1, this design retains the characteristics of the two-stage cold heads being driven by only one compressor and having a simple structure, while also allowing for the distribution of input power by adjusting the step ratio of the compressor piston and the volume of the compression chamber.

[0039] Example 4

[0040] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 4 As shown, the difference from Embodiment 3 is that the hot ends of the pulse tubes of the two-stage pulse tube refrigerators are connected to the same inertial tube and gas reservoir 3 as a phase adjustment device. Compared with Embodiment 3, this design has a more compact structure, and the use of the same inertial tube for phase adjustment in the two-stage pulse tube refrigerator can reduce the resistance loss in the inertial tube, increase the phase adjustment capability of the low-temperature stage, and thus improve the overall efficiency of the refrigerator.

[0041] Example 5

[0042] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 5 As shown, the difference from Embodiment 4 is that the hot ends of the pulse tubes of the two-stage pulse tube refrigerators are respectively connected to the two compression chambers of a stepped push piston 3' as phase adjustment and work recovery devices. Compared with Embodiment 4, this design increases the complexity of the system, adding a moving part to the cold end of the refrigerator, but it can recover expansion work, resulting in higher theoretical efficiency.

[0043] Example 6

[0044] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 6 As shown, the difference from Embodiment 5 is that the two-stage pulse tube refrigerator is driven by a single linear compressor 1, i.e., a single linear compressor 1 is used to connect the water coolers of the two-stage refrigerators respectively, while the two compression chambers of a stepped push piston 3' are respectively connected to the pulse tube hot ends of the two-stage refrigerators. Compared with Embodiment 5, this design simplifies the compressor structure, and the power distribution and phase distribution of the two-stage refrigerator can be adjusted by utilizing the step ratio of the stepped push piston.

[0045] Example 7

[0046] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 7 As shown, the difference from Embodiment 1 is that the second stage of this two-stage pulse tube refrigerator is located within the first stage, meaning the second-stage pulse tube 24-2 is at the center. The second-stage regenerator 22-2, the first-stage pulse tube 24-1, and the first-stage regenerator 22-1 are arranged coaxially outwards from the second stage, forming a layered structure. The first-stage water cooler 21-1 and the first-stage low-temperature heat exchanger 23-1 are located at opposite ends of the first-stage regenerator 22-1, forming the outermost layer. The second-stage water cooler 21-2 and the second-stage low-temperature heat exchanger 23-2 are located at opposite ends of the second-stage regenerator 22-2, forming the intermediate layer between the two pulse tubes. Compared to Embodiment 1, this design results in less local resistance of the working gas within the refrigerator.

[0047] Example 8

[0048] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 8 As shown, the difference from Embodiment 3 is that the hot end of the high-temperature stage pulse tube (i.e., the hot end of the first-stage pulse tube 24-1) of this two-stage pulse tube refrigerator is connected to the low-temperature stage water cooler (i.e., the second-stage water cooler 21-2). The expansion work of the high-temperature stage is recovered by the low-temperature stage pulse tube. This design has higher theoretical efficiency compared to Embodiment 3.

[0049] Example 9

[0050] A coaxial thermally coupled three-stage pulse tube refrigerator, such as Figure 9As shown, the difference from Embodiment 4 is that this refrigeration unit is three-stage. The three-stage cold heads are arranged coaxially: from the inside out, they are the third-stage pulse tube 24-3, the second-stage pulse tube 24-2, the first-stage pulse tube 24-1, the first-stage regenerator 22-1, the second-stage regenerator 22-2, and the third-stage regenerator 22-3. That is, the third-stage pulse tube 24-3 is located in the center, and the second-stage pulse tube 24-2, the first-stage pulse tube 24-1, the first-stage regenerator 22-1, the second-stage regenerator 22-2 and the third-stage regenerator 22-3 are arranged coaxially outward from it to form a layered structure. The first-stage water cooler 21-1 and the first-stage low-temperature end heat exchanger 23-1 are located at both ends of the first-stage regenerator 22-1, the second-stage water cooler 21-2 and the second-stage low-temperature end heat exchanger 23-2 are located at both ends of the second-stage regenerator 22-2, and the third-stage water cooler 21-3 and the third-stage low-temperature end heat exchanger 23-3 are located at both ends of the third-stage regenerator 22-3.

[0051] Compared to Example 4, this design can achieve a lower cooling temperature.

[0052] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A coaxial thermally coupled pulse tube refrigerator, comprising a compressor, a multi-stage cold head, and a phase-adjusting mechanism, characterized in that, The multi-stage cold head is thermally coupled and arranged coaxially to form a layered encapsulation structure; The cold head is configured with n stages, where n≥2. From the center outwards, the refrigeration unit consists of the nth stage pulse tube, the (n-1)th stage pulse tube, ..., the 1st stage pulse tube, the 1st stage regenerator, ..., the (n-1)th stage regenerator, and the nth stage regenerator, forming a coaxial structure with layers covering each other. The cold head is set in two stages. From the center to the outside, the cold head of the refrigeration unit consists of a low-temperature pulse tube, a high-temperature pulse tube, a high-temperature regenerator, and a low-temperature regenerator.

2. The coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that, The multi-stage cold head can be driven by a single linear compressor, multiple linear compressors, a stepped piston compressor, or a combination of linear and stepped piston compressors.

3. A coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that, Each level of the cold head consists of a water cooler, a regenerator, a cold end heat exchanger, and a pulse tube connected in sequence.

4. A coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that, All levels of cold heads use the same inertial tube and gas reservoir or separate inertial tubes and gas reservoirs as the phase adjustment mechanism.

5. A coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that, Each stage of the cold head uses a stepped push piston or a stepped piston as the phase adjustment mechanism.

6. The coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that, Thermal coupling between different levels of cold heads.

7. A coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that, The cold head can be configured as follows: n stages, n≥2, the refrigeration unit from the center outwards is the nth stage pulse tube, the nth stage regenerator, the (n-1)th stage pulse tube, the (n-1)th stage regenerator, ..., the 1st stage pulse tube, the 1st stage regenerator.

8. The coaxial thermally coupled pulse tube refrigerator according to claim 7, characterized in that, The cold head is set in two stages. From the center to the outside, the cold head of the refrigeration unit consists of a low-temperature pulse tube, a low-temperature regenerator, a high-temperature pulse tube, and a high-temperature regenerator.

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