A conical regenerator and a pulse tube refrigerator

Abstract

This invention belongs to the field of refrigeration technology, specifically relating to a conical regenerator and a pulse tube refrigeration machine. The regenerator has interconnected cylindrical and conical tapered structures, wherein the conical tapered structure makes the inner diameter of the hot end of the regenerator larger than the inner diameter of the cold end. The regenerator is filled with spherical regenerating packing within the conical tapered structure, with mesh packing filling at the hot end and spherical regenerating packing filling at the cold end. Compared with existing technologies, this invention solves the problem of weak heat exchange capacity in the low-temperature section (cold end) of the regenerator due to the slow flow rate of the working fluid. This solution effectively improves the heat exchange capacity of the regenerator in the low-temperature section (cold end).

Description

Technical Field

[0001] This invention belongs to the field of refrigeration technology, specifically relating to a conical regenerator and a pulse tube refrigeration machine. Background Technology

[0002] In recent years, with the rapid development of cutting-edge fields such as deep space exploration, quantum computing, and superconducting applications, the performance requirements for small cryogenic refrigerators have been increasing. Pulse tube refrigerators, due to their advantages of having no moving parts, high reliability, and long lifespan, have become one of the mainstream refrigeration solutions in these fields. Pulse tube refrigerators are regenerative gas refrigerators. Their principle is to achieve refrigeration by adiabatically evacuating high-pressure gas. In a pulse tube refrigerator, one end of the pulse tube is closed, and the other end is connected to a regenerator (regenerator) and a cold-end heat exchanger (refrigerator). When the high-pressure gas enters the pulse tube, it will be in a laminar flow state. Thus, during gas filling, a temperature gradient will be formed in the pulse tube due to compression. The temperature is highest at the closed end, while the heat of compression is carried away by the cooling water. Therefore, when the high-pressure gas is evacuated from the pulse tube, a cryogenic refrigeration zone will be formed at the outlet end of the pulse tube.

[0003] The regenerator is the core component of a pulse tube refrigerator, and its efficiency directly affects the overall refrigeration performance of the machine. Its key feature is that cold and hot fluids alternately flow through the same flow channel, and heat exchange occurs through direct contact between the fluids and the regenerating packing. Existing technologies, such as CN201463425U (disclosing a high-frequency regenerator and pulse tube refrigerator using stainless steel fiber regenerating packing), CN111595050A (disclosing a multi-stage pulse tube refrigerator device), and CN102147164A (disclosing a high-efficiency pulse tube refrigerator), typically employ a cylindrical structure in their regenerators, meaning the diameters of the hot and cold ends are identical. However, because the cold end temperature is relatively lower than the hot end, the working fluid (usually helium) experiences a gradual decrease in temperature, increase in density, and decrease in velocity as it flows from the hot end to the cold end. This results in lower convective heat transfer efficiency at the cold end and limits the regenerator's heat exchange capacity in the low-temperature region.

[0004] To improve heat transfer capacity in the low-temperature region, existing technologies, such as CN101551181B, disclose a variable cross-section regenerator for cryogenic refrigerators, including two types: one is a conical type with a gradually expanding pipe diameter from the hot end to the cold end, filled with deep cryogenic regenerative packing; the other is a combination of constant-diameter and variable-diameter pipes, where the variable-diameter section of the regenerator is filled with deep cryogenic regenerative packing, and the constant-diameter section is filled with wire mesh packing. This structure is only suitable for the 4K temperature range. At 4K, the specific heat capacity of the regenerator material drops sharply; for example, the volumetric specific heat capacity ratio of holmium copper to helium is only 0.6, a small ratio that results in significant heat loss. Therefore, this solution requires a variable cross-section regenerator design, increasing the pipe diameter in the low-temperature section, increasing the amount of deep cryogenic regenerative packing, and increasing the heat transfer area to improve regenerative performance. However, further increasing the pipe diameter causes the working fluid velocity to decrease further in the low-temperature section, which, while increasing the heat transfer area, reduces its convective heat transfer capacity.

[0005] In addition, the existing technology, A new tapered regenerator used for pulse tube refrigerator and its optimization, calculated the 80 K temperature range tapered regenerator, which proved that the regeneration effect was better than that of the cylindrical regenerator. However, the structure designed in this scheme is too ideal. Since the diameter of the mesh packing is fixed, it is difficult to continuously reduce the diameter in the tapered part, which makes it impossible to fill the regenerating packing in practice. Furthermore, this scheme is based on the thermophysical properties of the 80 K temperature range. However, the thermophysical properties of helium as the working fluid and the regenerating filler differ significantly with temperature at low temperatures. This means that the conclusions drawn by this scheme are only applicable to the verified 80 K temperature range and cannot be directly applied to operating conditions in other temperature ranges. Secondly, the volumetric specific heat of the regenerating filler varies greatly in different temperature ranges, and the volumetric specific heat is not a simple linear relationship with temperature. For example, the volumetric specific heat of holmium copper is inferior to that of stainless steel and copper wire mesh above 50 K, but superior to that of stainless steel and copper wire mesh below 50 K. Therefore, suitable low-temperature regenerating fillers are required in low-temperature operating conditions to control the operating temperature of the regenerating filler within a suitable range, which is very important for regenerators in the 20 K temperature range.

[0006] The 20 K temperature range is crucial for applications such as liquid hydrogen, high-temperature superconductivity, and deep space exploration. Therefore, a high-efficiency refrigerator suitable for this temperature range is urgently needed. Since the regenerator is a key component of the refrigerator and a major source of irreversible losses, improving its efficiency in the 20 K range is an effective approach for refrigerators designed for this region. However, current technologies only cover non-20 K temperature ranges such as 80 K and 4 K. Furthermore, the significant variations in packing characteristics across different temperature ranges prevent the direct application of existing research results to the 20 K range. Therefore, it is necessary to propose a regenerator and refrigerator suitable for the 20 K temperature range. Summary of the Invention

[0007] The purpose of this invention is to solve at least one of the aforementioned problems by providing a conical regenerator and a pulse tube refrigerator, thereby addressing the issues of weak heat exchange capacity in the low-temperature section (cold end) of the regenerator due to the slow flow rate of the working fluid in the low-temperature section (cold end) in the prior art, and the difficulty in filling the existing tapered regenerator with regenerative packing material. This solution effectively improves the heat exchange capacity of the regenerator in the low-temperature section (cold end).

[0008] The objective of this invention is achieved through the following technical solution: The first aspect of the present invention discloses a conical regenerator, wherein the regenerator has an interconnected cylindrical structure and a tapered conical structure, wherein the tapered conical structure makes the inner diameter of the hot end of the regenerator larger than the inner diameter of the cold end of the regenerator. The regenerator is filled with spherical regenerating packing within a tapered, tapering structure. The hot end of the regenerator is filled with mesh packing, and the cold end of the regenerator is filled with spherical regenerating packing.

[0009] Preferably, the regenerator is filled with wire mesh regenerating filler and / or spherical regenerating filler.

[0010] Preferably, the regenerator includes a hot-end straight section, a middle conical section, and a cold-end straight section connected in sequence. Both the hot-end straight section and the cold-end straight section are cylindrical structures, and the inner diameter of the hot-end straight section is larger than the inner diameter of the cold-end straight section. The middle conical section has a tapered structure with its inner diameter continuously decreasing from the hot end to the cold end. The inner diameter of the middle conical section connected to the hot end straight cylinder section is equal to the inner diameter of the hot end straight cylinder section, and the inner diameter of the middle conical section connected to the cold end straight cylinder section is equal to the inner diameter of the cold end straight cylinder section. The middle conical section is filled with spherical regenerative packing. The end of the hot-end straight section away from the middle conical section is connected to the compressor; The end of the cold-end straight section away from the middle conical section is connected to the blood vessel.

[0011] Preferably, the regenerator includes a hot-end straight section and a middle conical section that are connected to each other; The hot-end straight section has a cylindrical structure; The middle conical section is a tapered structure with an inner diameter that continuously decreases from the hot end to the cold end. The inner diameter of the end of the middle conical section that connects to the hot end straight cylinder section is equal to the inner diameter of the hot end straight cylinder section. The middle conical section is filled with spherical regenerative packing. The end of the hot-end straight section away from the middle conical section is connected to the compressor; The middle conical section, away from the hot end of the straight cylindrical section, connects to the blood vessel.

[0012] Preferably, the middle conical section is filled with spherical regenerative packing material, which is holmium copper spherical regenerative packing material or lead shot regenerative packing material; The mesh filler includes stainless steel wire mesh.

[0013] Within the 20 K temperature range, numerical simulations show that a structure that gradually tapers from the hot end to the cold end can improve the gas flow velocity and heat transfer coefficient at the cold end. However, this structure presents significant difficulties when actually filling regenerative packing materials such as mesh packings that are difficult to continuously change in size. Therefore, this design specifically employs spherical regenerative packing materials in the middle conical section to overcome the filling problems and defects of mesh regenerative packing materials in a tapered conical structure.

[0014] Based on this, this solution incorporates a tapering mechanism and fills the cold end section, where increased flow rate is required, with spherical regenerative filler, according to the applicable temperature range. Meanwhile, the hot end adopts a cylindrical structure and is filled with stainless steel wire mesh, which has better performance in the high-temperature zone.

[0015] A second aspect of the present invention discloses a pulse tube refrigerator, comprising a compressor, a pulse tube, a phase-adjusting mechanism, and a regenerator as described above; The compressor is connected to the radiator via a pipeline, and the compressor is connected to the hot end of the regenerator via the radiator. The cold end of the regenerator is connected to the first end of the pulse tube via a cold end heat exchanger. A hot-end heat exchanger is provided at the second end of the pulse tube, and the hot-end heat exchanger is connected to the phase adjustment mechanism through a pipeline.

[0016] Preferably, the pulse tube refrigerator is a GM type pulse tube refrigerator or a Stirling type pulse tube refrigerator.

[0017] Preferably, the pulse tube refrigerator is a linear pulse tube refrigerator, a coaxial pulse tube refrigerator, or a U-shaped pulse tube refrigerator.

[0018] Preferably, the compressor is connected to the radiator via parallel piping; The parallel pipeline includes a high-pressure pipeline and a low-pressure pipeline connected in parallel. A high-pressure valve is installed on the high-pressure pipeline, and a low-pressure valve is installed on the low-pressure pipeline.

[0019] Preferably, the pulse tube refrigerator further includes a two-way air inlet valve; The bidirectional air intake valve is connected between the hot end of the regenerator and the second end of the pulse tube.

[0020] Preferably, the phase adjustment mechanism is a small-hole gas cell phase adjustment mechanism or an active gas cell phase adjustment mechanism; The orifice gas chamber phase adjustment mechanism includes an orifice gas chamber, and a control valve is installed on the pipeline between the orifice gas chamber and the second end of the hot end heat exchanger. The active gas storage phase adjustment mechanism includes several gas storage units arranged in parallel, and each gas storage unit is equipped with a control valve on each branch between the second end of the hot end heat exchanger and the second end of the hot end heat exchanger.

[0021] Preferably, when the pulse tube refrigerator has a multi-stage structure, the regenerator of any one or more stages adopts any of the regenerators described above.

[0022] The working principle of this invention is as follows: The regenerator of the present invention forms a flow channel with a reduced inner diameter near the cold end, which can effectively increase the working fluid flow rate in the cooling section of the regenerator, thereby effectively enhancing the convective heat transfer efficiency at the cold end of the regenerator, while improving the airflow uniformity. The improved airflow uniformity further helps to reduce the loss of the working fluid (helium) during the flow process.

[0023] Meanwhile, considering that the temperature distribution of the regenerating packing in the regenerator is related to the effective volume of the packing, this invention not only improves the structure of the existing cylindrical regenerator and adopts a tapered tapered structure in the middle conical section, but also fills the cold end and the part near the cold end with low-temperature regenerating packing holmium copper and the hot end with mesh packing, so as to give full play to the performance of the regenerating packing and increase the flow rate and heat transfer coefficient of the working fluid in the cold end of the regenerator.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a conical section with a tapered tapered structure at the cold end of the regenerator, which significantly increases the flow velocity of the working fluid in the low temperature region, enhances the convective heat transfer efficiency at the cold end, and effectively makes up for the deficiency of insufficient heat transfer capacity at the cold end of the traditional cylindrical regenerator.

[0025] 2. This invention employs a combined structure of a hot-end straight cylindrical section, a middle conical section, and a cold-end straight cylindrical section. This structure retains the excellent heat transfer characteristics of wire mesh filling in the ambient temperature range while utilizing the conical section to accommodate spherical packing, thus avoiding the technological difficulties associated with wire mesh filling in an integral tapered regenerator. Specifically, since the cold end and areas near the cold end of the regenerator require deep-temperature regenerating packing materials such as holmium copper or lead shot, which are all spherical regenerating packing materials, the designed tapered tapered structure can conveniently accommodate these types of spherical regenerating packing materials.

[0026] 3. The present invention has a flexible structure and can be used for different pulse tube refrigerator drive methods of GM type or Stirling type. It can be adapted to various pulse tube refrigerator mechanism types such as linear type, coaxial type, and U type. It can also be applied to each stage of the cold head of multi-stage refrigerator and has a wide range of application prospects.

[0027] This invention presents numerical calculations and experimental tests on the performance of the regenerator in the 20 K temperature range, demonstrating significantly superior performance compared to similar refrigeration units using conventional cylindrical regenerators. Furthermore, the improved structure of this invention allows for the rational setting of the regenerator diameter according to different needs; in particular, the three-section structural design allows for the rational allocation of the regenerating packing volume based on actual requirements. The invention fills the cold end and the area near the cold end with holmium copper, fully utilizing the volumetric specific heat advantage of holmium copper, while filling the hot end with wire mesh, taking into account both the actual filling of the regenerator and enabling temperature control of the regenerating packing. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the linear pulse tube refrigerator in Embodiment 1 of the present invention.

[0029] Figure 2 This is a schematic diagram of the coaxial pulse tube refrigerator in Embodiment 2 of the present invention.

[0030] Figure 3 This is a schematic diagram of the U-shaped pulse tube refrigerator in Embodiment 3 of the present invention.

[0031] Figure 4 This is a schematic diagram of the conical regenerator in Embodiment 4 of the present invention.

[0032] Figure 5 This is a schematic diagram of the bidirectional air intake pulse tube refrigerator in Embodiment 5 of the present invention.

[0033] Figure 6 This is a schematic diagram of the active gas reservoir type pulse tube refrigerator in Embodiment 6 of the present invention.

[0034] Figure 7 This is a schematic diagram of the Stirling-type pulse tube refrigerator in Embodiment 7 of the present invention.

[0035] Figure 8The numerical simulation results are for Embodiment 1 and Comparative Example 1 of the present invention.

[0036] In the diagram: 1-Compressor; 21-High-pressure valve; 22-Low-pressure valve; 31-Radiator; 32-Regenerator; 321-Hot end straight section; 322-Middle section conical section; 323-Cold end straight section; 33-Cold end heat exchanger; 34-Pulse tube; 35-Hot end heat exchanger; 36-Phase adjustment mechanism; 37-Two-way intake valve. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0038] The conical regenerator 32 and its tapered structure described in this invention can be widely applied to various pulse tube refrigerators. Depending on the driving method, pulse tube refrigerators can be divided into GM-type pulse tube refrigerators and Stirling-type pulse tube refrigerators; and depending on the structural arrangement, pulse tube refrigerators can be divided into linear, coaxial, and U-type. The above driving methods and structural arrangements can be arbitrarily combined to form various specific models. Unless otherwise specified, the following embodiments use the GM-type as an example and describe the three typical structures: linear, coaxial, and U-type. The application of the GM-type and Stirling-type regenerators in the regenerator 32 structure is similar and will not be repeated.

[0039] Example 1 A conical regenerator 32 has an interconnected cylindrical structure and a tapered conical structure, wherein the tapered conical structure makes the inner diameter of the hot end of the regenerator 32 larger than the inner diameter of the cold end of the regenerator 32. The hot end of the regenerator 32 is provided with a radiator 31 for connecting to the compressor 1; The cold end of the regenerator 32 is provided with a cold end heat exchanger 33 for connecting to the pulse tube 34; The regenerator 32 is filled with spherical regenerating packing in a tapered conical structure. The hot end of the regenerator 32 is filled with mesh packing, and the cold end of the regenerator 32 is filled with holmium copper packing.

[0040] A pulse tube refrigerator includes a compressor 1, a pulse tube 34, a phase adjustment mechanism 36, and a regenerator 32 as described above. The compressor 1 is connected to the radiator 31 through a pipeline, and the compressor 1 is connected to the hot end of the regenerator 32 through the radiator 31. The cold end of the regenerator 32 is connected to the first end of the pulse tube 34 via the cold end heat exchanger 33. The second end of the pulse tube 34 is provided with a hot end heat exchanger 35, and the hot end heat exchanger 35 is connected to the phase adjustment mechanism 36 through a pipeline.

[0041] More specifically, in this embodiment: like Figure 1 As shown, a linear pulse tube refrigerator includes a compressor 1, a high-pressure valve 21, a low-pressure valve 22, a radiator 31, a conical regenerator 32, a cold-end heat exchanger 33, a pulse tube 34, a hot-end heat exchanger 35, and a small-hole gas storage phase adjustment mechanism 36.

[0042] In this embodiment, the regenerator 32 is a conical regenerator 32, which includes a hot-end straight section 321, a middle conical section 322, and a cold-end straight section 323. The inner diameter of the hot-end straight section 321 remains unchanged, and it is filled with wire mesh regenerating filler or spherical regenerating filler. In this embodiment, stainless steel wire mesh is preferred as the mesh filler. The middle conical section 322 is filled with spherical regenerating filler, and its inner diameter gradually decreases (continuously changes) along the temperature decreasing direction (from the hot end to the cold end). The inner diameter of the middle conical section 322 connected to the hot-end straight section 321 is equal to the inner diameter of the hot-end straight section 321, and the inner diameter of the middle conical section 322 connected to the cold-end straight section 323 is equal to the inner diameter of the cold-end straight section 323. The cold-end straight section 323 is close to the cold-end heat exchanger 33, and its inner diameter remains unchanged. It is filled with wire mesh regenerating filler or spherical material. In this embodiment, both the middle conical section 322 and the cold end straight section 323 are filled with spherical holmium copper filler. In other embodiments, appropriate low-temperature spherical regenerating fillers such as lead shot regenerating fillers may also be filled.

[0043] The compressor 1 is connected to the radiator 31 through parallel high-pressure and low-pressure pipelines, and a high-pressure valve 21 and a low-pressure valve 22 are respectively installed on the high-pressure and low-pressure pipelines; the radiator 31 is located at the hot end of the regenerator 32 (located in the hot end straight section 321); a cold end heat exchanger 33 is installed at the cold end of the regenerator 32 and is connected to one end of the pulse tube 34; the other end of the pulse tube 34 is equipped with the hot end radiator 31; the hot end radiator 31 is further connected to the small-hole gas storage phase adjustment mechanism 36 through a pipeline.

[0044] The working fluid (usually helium) is driven by compressor 1, distributed via high-pressure valve 21 and low-pressure valve 22, cooled to room temperature by radiator 31, and then flows sequentially through hot-end straight section 321, middle conical section 322, and cold-end straight section 323. In the middle conical section 322, the flow cross-sectional area gradually decreases, resulting in a significant increase in the working fluid velocity, thereby enhancing convective heat transfer between the working fluid and the spherical packing. The working fluid then absorbs heat in cold-end heat exchanger 33 before entering pulse tube 34, and then releases heat at hot-end heat exchanger 35. Finally, phase adjustment is completed by orifice gas chamber phase adjustment mechanism 36.

[0045] This embodiment effectively improves the heat exchange efficiency of the cold end of the regenerator 32 through the conical section structure, while avoiding the technological difficulties of wire mesh filling in the overall conical tapered structure. Specifically, considering the limitations of the conical tapered structure (middle conical section 322) on the filling material, this solution uses spherical filling material in the middle conical section 322. This not only satisfies the feasibility of actual filling, but also allows the holmium copper to be closer to and located at the cold end, thus more fully utilizing its volumetric specific heat advantage in the low-temperature region.

[0046] Comparative Example 1 Based on Example 1, the middle conical segment 322 is replaced with other structural forms (cylindrical structure or stepped structure), and the rest remains unchanged.

[0047] Numerical simulations were performed on three different regenerator structures, such as... Figure 8 As shown in Table 1, the simulation results show that the conical regenerator can improve the cold end velocity and heat transfer coefficient compared with the cylindrical regenerator, and the airflow is more uniform compared with the stepped regenerator.

[0048] Table 1. Heat transfer performance of the cold end section under three structures in Example 1 and Comparative Example 1 Example 2 like Figure 2 As shown, the coaxial pulse tube refrigerator of this embodiment is basically the same as the pulse tube refrigerator disclosed in Embodiment 1. The difference from Embodiment 1 is that the refrigerator adopts a coaxial structure arrangement: the tapered tapered structure of the regenerator 32 is located in the inner or outer layer of the coaxially arranged pulse tube 34, and the specific position is determined according to the number of refrigerator stages and structural design.

[0049] In this embodiment, the regenerator 32 also includes a hot-end straight section 321, a middle conical section 322, and a cold-end straight section 323, and the internal filling method is the same as in Embodiment 1.

[0050] In this embodiment, due to the structural characteristics of the coaxial refrigerator, the hot end heat exchanger 35 and the radiator 31 can be the same heat exchanger.

[0051] Example 3 like Figure 3 As shown, the U-shaped pulse tube refrigerator of this embodiment is basically the same as the pulse tube refrigerator disclosed in Embodiment 1. The difference from Embodiment 1 is that the refrigerator adopts a U-shaped structure arrangement, that is, the regenerator 32 and the pulse tube 34 are arranged in parallel, and the cold end heat exchanger 33 and the pulse tube 34 are connected by a pipeline.

[0052] The regenerator 32 still adopts a combination structure of hot end straight section 321, middle section conical section 322 and cold end straight section 323. The conical section is arranged close to the cold end heat exchanger 33, that is, the cold end heat exchanger 33 is directly connected to the cold end of the regenerator 32.

[0053] Example 4 like Figure 4 As shown, this embodiment discloses a conical regenerator 32, which is a parallel structural scheme of the present invention. Taking a linear pulse tube refrigerator as an example, it can be used in other pulse tube refrigerators such as coaxial or U-shaped ones.

[0054] The difference between this embodiment and Embodiment 1 is that the regenerator 32 does not include the cold-end straight section 323, and the middle conical section 322 is directly connected to the cold-end heat exchanger 33 (the hot-end straight section 321 is consistent with Embodiment 1). The middle conical section 322 is filled with spherical regenerating packing.

[0055] This structure can also achieve the effect of increasing the flow rate at the cold end.

[0056] Example 5 like Figure 5 As shown, this embodiment discloses a bidirectional air intake pulse tube refrigerator. Taking a linear pulse tube refrigerator as an example, the difference from Embodiment 1 is that the pulse tube refrigerator adopts a bidirectional air intake phase adjustment mechanism 36, which can be used for pulse tube refrigerators with other structures such as coaxial or U-shaped.

[0057] In addition to the structure of Embodiment 1, the pulse tube refrigerator further adds a pipeline to connect the hot end of the pulse tube 34 to the radiator 31, and adds a two-way intake valve 37 on the pipeline to control the flow rate.

[0058] Example 6 like Figure 6 As shown, this embodiment discloses an active gas reservoir type pulse tube refrigerator. Taking a linear pulse tube refrigerator as an example, the difference from Embodiment 1 is that the pulse tube refrigerator adopts an active gas reservoir phase adjustment mechanism 36, which can be used for pulse tube refrigerators with other structures such as coaxial or U-shaped.

[0059] The pulse tube refrigerator specifically uses three parallel gas reservoirs connected to the hot end of the pulse tube 34 (hot end heat exchanger 35), replacing the small-hole gas reservoir phase adjustment mechanism 36 originally used in Example 1. The three gas reservoirs are equipped with control valves on each branch, thereby forming an active gas reservoir phase adjustment mechanism 36 by controlling the opening and closing of the three gas reservoirs in a fixed sequence.

[0060] This structural design is more efficient than that of Example 1.

[0061] Further experimental testing was conducted on the single-stage active gas-sump pulse tube refrigerator using a conical regenerator in this embodiment. Its cooling capacity at 20 K was 28.36 W, which is significantly higher than that of the single-stage active gas-sump pulse tube refrigerator (20 K@17 W) using a cylindrical regenerator abroad.

[0062] Example 7 like Figure 7 As shown, this embodiment discloses a bidirectional air intake pulse tube refrigerator. Taking a linear pulse tube refrigerator as an example, the difference from embodiment 6 is that the pulse tube refrigerator is a Stirling type pulse tube refrigerator, which can be used for other structures such as coaxial or U-shaped pulse tube refrigerators.

[0063] 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.

[0064] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A conical regenerator, characterized in that, The regenerator (32) has an interconnected cylindrical structure and a tapered conical structure, wherein the tapered conical structure makes the inner diameter of the hot end of the regenerator (32) larger than the inner diameter of the cold end of the regenerator (32). The regenerator (32) is filled with spherical regenerating packing in a tapered conical structure. The hot end of the regenerator (32) is filled with mesh packing, and the cold end of the regenerator (32) is filled with spherical regenerating packing.

2. The conical regenerator according to claim 1, characterized in that, The regenerator (32) includes a hot-end straight section (321), a middle conical section (322), and a cold-end straight section (323) connected in sequence. Both the hot-end straight section (321) and the cold-end straight section (323) are cylindrical structures, and the inner diameter of the hot-end straight section (321) is larger than the inner diameter of the cold-end straight section (323). The middle conical section (322) has a tapered structure with its inner diameter decreasing continuously from the hot end to the cold end. The inner diameter of the middle conical section (322) connected to the hot end straight section (321) is equal to the inner diameter of the hot end straight section (321). The inner diameter of the middle conical section (322) connected to the cold end straight section (323) is equal to the inner diameter of the cold end straight section (323). The middle conical section (322) is filled with spherical heat-regenerating filler. The end of the hot-end straight section (321) away from the middle conical section (322) is connected to the compressor (1); The end of the cold-end straight section (323) away from the middle conical section (322) is connected to the blood vessel (34).

3. The conical regenerator according to claim 1, characterized in that, The regenerator (32) includes a hot-end straight section (321) and a middle conical section (322) that are connected to each other. The hot end straight section (321) has a cylindrical structure; The middle conical section (322) is a tapered structure with an inner diameter that decreases continuously from the hot end to the cold end. The inner diameter of the middle conical section (322) connected to the hot end straight section (321) is equal to the inner diameter of the hot end straight section (321). The middle conical section (322) is filled with spherical heat-returning packing. The end of the hot-end straight section (321) away from the middle conical section (322) is connected to the compressor (1); The middle conical section (322) is connected to the blood vessel (34) at the end away from the hot end straight section (321).

4. The conical regenerator according to claim 1, characterized in that, The spherical regenerating packing is either holmium copper spherical regenerating packing or lead shot regenerating packing; The mesh filler includes stainless steel wire mesh.

5. A pulse tube refrigerator, characterized in that, Includes a compressor (1), a pulse tube (34), a phase adjustment mechanism (36), and a regenerator (32) as described in any one of claims 1-4; The compressor (1) is connected to the radiator (31) through a pipeline, and the compressor (1) is connected to the hot end of the regenerator (32) through the radiator (31); The cold end of the regenerator (32) is connected to the first end of the pulse tube (34) via a cold end heat exchanger (33); The second end of the pulse tube (34) is provided with a hot end heat exchanger (35), and the hot end heat exchanger (35) is connected to the phase adjustment mechanism (36) through a pipeline.

6. The pulse tube refrigerator according to claim 5, characterized in that, The pulse tube refrigerator is either a GM type pulse tube refrigerator or a Stirling type pulse tube refrigerator.

7. The pulse tube refrigerator according to claim 5, characterized in that, The pulse tube refrigerator is a linear pulse tube refrigerator, a coaxial pulse tube refrigerator, or a U-shaped pulse tube refrigerator.

8. The pulse tube refrigerator according to claim 5, characterized in that, The compressor (1) is connected to the radiator (31) through a parallel pipeline; The parallel pipeline includes a high-pressure pipeline and a low-pressure pipeline connected in parallel. A high-pressure valve (21) is installed on the high-pressure pipeline, and a low-pressure valve (22) is installed on the low-pressure pipeline.

9. A pulse tube refrigerator according to claim 5, characterized in that, The pulse tube refrigerator also includes a two-way intake valve (37). The bidirectional intake valve (37) is connected between the hot end of the regenerator (32) and the second end of the pulse tube (34).

10. A pulse tube refrigerator according to claim 5, characterized in that, The phase adjustment mechanism (36) is a small-hole gas cell phase adjustment mechanism or an active gas cell phase adjustment mechanism; The orifice gas storage phase adjustment mechanism includes an orifice gas storage, and a control valve is provided on the pipeline between the orifice gas storage and the second end of the hot end heat exchanger (35); The active gas storage phase adjustment mechanism includes several gas storage units arranged in parallel, and each gas storage unit is equipped with a control valve on each branch between the second end of the hot end heat exchanger (35).

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