Coaxial thermal coupling pulse tube refrigerator

Abstract

The invention relates to a coaxial thermal coupling pulse tube refrigerator which comprises a compressor, a multi-stage cold head and a phase modulation mechanism, the multi-stage cold head is thermally coupled and coaxially arranged, and a high-temperature-stage pulse tube and a heat regenerator are respectively placed on the outer side of a low-temperature-stage pulse tube. Compared with the prior art, the device is compact in structure and high in reliability.

Description

Technical Field

[0001] The invention relates to a refrigerator, in particular to a coaxial thermally coupled pulse tube refrigerator. Background Art

[0002] In recent years, with the rapid development of key fields such as aerospace, the demand for low-temperature environments has been growing. This trend has greatly promoted the rapid development of small cryogenic refrigerator technology. In a variety of application scenarios, the requirements for the reliability, life and weight of refrigerators are gradually increasing. Especially in the field of deep space exploration, more stringent standards are put forward for the performance of refrigerators.

[0003] Deep space probes often need to work for a long time in extreme space environments, which requires the refrigerator to not only have efficient cooling capabilities, but also to ensure extremely high reliability and long service life. In addition, considering the strict weight and space restrictions of the probe, the size and weight of the refrigerator must also be reduced as much as possible. Therefore, the development of a small cryogenic refrigerator with a compact structure and excellent performance is crucial to promoting the advancement of deep space exploration technology. Summary of the invention

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

[0005] The object of the present invention can be achieved through the following technical scheme: 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 structure.

[0006] Furthermore, the cold head is arranged in n stages, n≥2, and the refrigerators from the center to the outside are respectively the nth stage pulse tube, the n-1th stage pulse tube, ..., the 1st stage pulse tube, the 1st stage heat regenerator, ..., the n-1th stage heat regenerator, and the nth stage heat regenerator, forming a coaxial structure with layers of coating.

[0007] Furthermore, the cold head is arranged in n stages, n≥2, and the refrigerators from the center to the outside are respectively the nth stage pulse tube, the nth stage heat regenerator, the n-1th stage pulse tube, the n-1th stage heat regenerator, ..., the 1st stage pulse tube, and the 1st stage heat regenerator.

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

[0009] Furthermore, each level of cold head is formed by sequentially connecting a water cooler, a heat regenerator, a cold end heat exchanger and a pulse tube.

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

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

[0012] Furthermore, each stage of the cold heads is thermally coupled.

[0013] Furthermore, the cold head is arranged in two levels, and the cold head of the refrigerator is respectively a low-temperature level pulse tube, a high-temperature level pulse tube, a high-temperature level regenerator, and a low-temperature level regenerator from the center to the outside.

[0014] Furthermore, the cold head is arranged in two levels, and the cold head of the refrigerator is respectively a low-temperature level pulse tube, a low-temperature level regenerator, a high-temperature level pulse tube, and a high-temperature level regenerator from the center to the outside.

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

[0016] 1. The coaxial heat-coupled pulse tube refrigerator of the present invention adopts a coaxial arrangement between multiple stages, and the pulse tube and the regenerator of the high-temperature stage are respectively placed on the outside of the low-temperature stage. It has a compact structure and high reliability, and is particularly suitable for occasions such as deep space exploration that have high requirements on the quality of refrigerators.

[0017] 2. The phase adjustment mechanism of the present invention can be a phase adjustment mechanism with separate inertia tubes and gas reservoirs at each level, a common inertia tube phase adjustment mechanism (i.e., the hot ends of the pulse tubes of the multi-stage cold head are connected to the same inertia tube and gas reservoir) or a stepped push piston (i.e., the hot ends of the pulse tubes of the multi-stage cold head are respectively connected to different expansion chambers of the stepped push piston). This can further reduce the number of components, weight and volume, but can achieve the same cooling effect.

[0018] 4. The compressor described in the present invention is a multi-stage stepped piston compressor, a linear compressor, or a combination of several of them. The compressor is a multi-stage stepped piston compressor, or the compressor is a plurality of linear compressors; or the compressor is a linear compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The coaxial thermally coupled two-stage pulse tube refrigerator of Example 1;

[0020] Figure 2 The coaxial thermally coupled two-stage pulse tube refrigerator of Example 2;

[0021] Figure 3 The coaxial thermally coupled two-stage pulse tube refrigerator of Example 3;

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

[0023] Figure 5 The coaxial thermally coupled two-stage pulse tube refrigerator of Example 5;

[0024] Figure 6 The coaxial thermally coupled two-stage pulse tube refrigerator of Example 6;

[0025] Figure 7 The coaxial thermally coupled two-stage pulse tube refrigerator of Example 7;

[0026] Figure 8 The coaxial thermally coupled three-stage pulse tube refrigerator of Example 8;

[0027] Fig. 9 This is the coaxial thermally coupled three-stage pulse tube refrigerator of Example 9. DETAILED DESCRIPTION

[0028] The present invention is described in detail below 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 comprises a compression mechanism 1, a multi-stage cold head, and a phase adjustment mechanism. The multi-stage cold head is two-stage in this embodiment, and each cold head comprises a water cooler, a regenerator, a low temperature end heat exchanger and a pulse tube. Specifically, Figure 1 The first-stage cold head includes: a first-stage water cooler 21-1, a first-stage heat 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 heat 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] Among them, the two-stage cold head adopts a coaxial arrangement: from the inside to the outside, 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. That is, the second-stage pulse tube 24-2 is located at the center, and the first-stage pulse tube 24-1, the first-stage regenerator 22-1, and the second-stage regenerator 22-2 are coaxially arranged outward in sequence on its outside to form a layered structure, the first-stage water cooler 21-1 and the first-stage low-temperature end heat exchanger 23-1 are respectively located at the two ends of the first-stage regenerator 22-1, and the second-stage water cooler 21-2 and the second-stage low-temperature end heat exchanger 23-2 are respectively located at the two ends of the second-stage regenerator 22-2.

[0032] A linear compressor 1 is connected to the water coolers of the two-stage cold heads at the same time, and work distribution is performed at the compressor outlet. The hot ends of the pulse tubes of the two-stage cold heads are respectively connected to two inertia tubes as phase adjustment mechanisms.

[0033] The two-stage pulse tube refrigerator is filled with high-pressure working fluid. Compressor 1 is responsible for driving the cold head of the pulse tube refrigerator to produce a refrigeration effect.

[0034] After the working fluid in compressor 1 is compressed approximately adiabatically, it enters the two-stage cold head respectively, is cooled to room temperature in each water cooler, and then is further cooled to low temperature through the regenerator. The working fluid absorbs external heat in the low-temperature end heat exchanger to generate cooling capacity, and then expands in the pulse tube. The function of the phase adjustment mechanism is to adjust the phase of the mass flow and pressure wave inside the pulse tube refrigerator so that they are in phase at the middle position of the regenerator, thereby minimizing the regenerator loss.

[0035] Example 2

[0036] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 2 As shown, the difference from Example 1 is that the two-stage cold heads of the two-stage pulse tube refrigerator are driven by two separate linear compressors, that is, 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 with Example 1, the structure of the compressor is more complicated, but the two-stage refrigerator can operate at different frequencies, charging pressures and input work, which is convenient for adjusting the parameters of the refrigerator to obtain better refrigeration efficiency and larger refrigeration capacity.

[0037] Example 3

[0038] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 3 As shown, the difference from Example 1 is that the two-stage cold heads of the 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 Example 1, this design retains the characteristics of the two-stage cold heads being driven by only one compressor and having a simple structure, while the input work can be distributed by adjusting the step ratio of the compressor piston and the compression chamber volume.

[0039] Example 4

[0040] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 4 As shown, the difference from Example 3 is that the hot ends of the pulse tubes of the two-stage cold heads of the two-stage pulse tube refrigerator are connected to the same inertia tube and gas reservoir 3 as a phase adjustment device. Compared with Example 3, this design has a more compact structure, and the two-stage pulse tube refrigerator uses the same inertia tube for phase adjustment, which can reduce the resistance loss in the inertia 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 Example 4 is that the hot ends of the pulse tubes of the two-stage cold heads of the two-stage pulse tube refrigerator are respectively connected to two compression chambers of a stepped push piston 3' as a phase adjustment and work recovery device. Compared with Example 4, this design increases the complexity of the system and adds a moving part to the cold end of the refrigerator, but it can recover the expansion work and has a 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 Example 5 is that the two-stage cold heads of the two-stage pulse tube refrigerator are driven by a linear compressor 1, that is, a linear compressor 1 is used to connect the water coolers of the two-stage cold heads respectively, and at the same time, two compression chambers of a stepped piston 3' are connected to the pulse tube hot ends of the two-stage cold heads respectively. Compared with Example 5, the structure of the compressor is simplified in this design, and the work distribution and phase distribution of the two-stage refrigerator can be adjusted by using the step ratio of the stepped piston.

[0045] Example 7

[0046] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 7 As shown, the difference from Example 1 is that the second stage of the two-stage pulse tube refrigerator is located at the first stage, that is, the second stage pulse tube 24-2 is located at the center, and the second stage heat exchanger 22-2, the first stage pulse tube 24-1 and the first stage heat exchanger 22-1 are coaxially arranged outward in sequence on the outside to form a layered structure, the first stage water cooler 21-1 and the first stage low temperature end heat exchanger 23-1 are respectively located at both ends of the first stage heat exchanger 22-1, as the outermost layer, the second stage water cooler 21-2 and the second stage low temperature end heat exchanger 23-2 are respectively located at both ends of the second stage heat exchanger 22-2, forming an intermediate layer between the two stages of pulse tubes. Compared with Example 1, this design has a smaller local resistance of the working gas in the refrigerator.

[0047] Example 8

[0048] A coaxial thermally coupled two-stage pulse tube refrigerator, such as Figure 8 As shown, the difference from Example 3 is that the hot end of the high-temperature pulse tube of the two-stage pulse tube refrigerator (i.e., the hot end of the first-stage pulse tube 24-1) is connected to the low-temperature 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 pulse tube. Compared with Example 3, this design has a higher theoretical efficiency.

[0049] Example 9

[0050] A coaxial thermally coupled three-stage pulse tube refrigerator, such as Fig. 9As shown, the difference from Example 4 is that the refrigerator is three-stage. The three-stage cold head is arranged coaxially: from the inside to the outside, 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 at the center position, and the second-stage pulse tube 24-2, the first-stage pulse tube 24-1, the first-stage heat regenerator 22-1, the second-stage heat regenerator 22-2 and the third-stage heat regenerator 22-3 are coaxially arranged outward on the outside thereof, forming a layered structure, the first-stage water cooler 21-1 and the first-stage low-temperature end heat exchanger 23-1 are respectively located at the two ends of the first-stage heat regenerator 22-1, the second-stage water cooler 21-2 and the second-stage low-temperature end heat exchanger 23-2 are respectively located at the two ends of the second-stage heat regenerator 22-2, and the third-stage water cooler 21-3 and the third-stage low-temperature end heat exchanger 23-3 are respectively located at the two ends of the third-stage heat regenerator 22-3.

[0051] Compared with Example 4, this design can achieve a lower refrigeration temperature.

[0052] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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 only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A coaxial thermally coupled pulse tube refrigerator, comprising a compressor, a multi-stage cold head and a phase adjustment mechanism, characterized in that: The multi-stage cold heads are thermally coupled and coaxially arranged to form a layered covering structure.

2. A coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that: The cold head is arranged in n stages, n≥2, and the refrigerator is respectively arranged from the center to the outside of the nth stage pulse tube, the n-1th stage pulse tube, ..., the 1st stage pulse tube, the 1st stage heat regenerator, ..., the n-1th stage heat regenerator, and the nth stage heat regenerator, forming a coaxial structure with layers of coating.

3. The coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that: The cold head is arranged in n stages, n≥2, and the refrigerator from the center to the outside is respectively the nth stage pulse tube, the nth stage regenerator, the n-1th stage pulse tube, the n-1th stage regenerator, ..., the 1st stage pulse tube, the 1st stage regenerator.

4. A coaxial thermally coupled pulse tube refrigerator according to claim 1, 2 or 3, characterized in that: The multi-stage cold head is driven by one linear compressor, or by multiple linear compressors, or by a stepped piston compressor, or by a combination of a linear compressor and a stepped piston compressor.

5. The coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that: Each level of cold head is connected in sequence by a water cooler, a heat regenerator, a cold end heat exchanger and a pulse tube.

6. The coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that: Each level of cold heads uses the same inertia tube and gas reservoir or separate inertia tubes and gas reservoirs as a phase adjustment mechanism.

7. The coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that: Each level of cold head adopts a stepped push piston or a stepped piston as a phase adjustment mechanism.

8. The coaxial thermally coupled pulse tube refrigerator according to claim 1, characterized in that: The cold heads at each stage are thermally coupled.

9. The coaxial thermally coupled pulse tube refrigerator according to claim 2, characterized in that: The cold head is set in two levels, and the cold head of the refrigerator is composed of a low-temperature pulse tube, a high-temperature pulse tube, a high-temperature regenerator, and a low-temperature regenerator from the center to the outside.

10. The coaxial thermally coupled pulse tube refrigerator according to claim 3, characterized in that: The cold head is set in two levels. The cold head of the refrigerator is composed of a low-temperature pulse tube, a low-temperature regenerator, a high-temperature pulse tube, and a high-temperature regenerator from the center to the outside.

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