A pulse tube refrigerator inlet and return air pipe

Abstract

The present invention provides an air inlet and return pipe for a pulse tube refrigerator, comprising an air inlet and return pipe main body and end nuts connected to both ends of the air inlet and return pipe main body, the air inlet and return pipe main body being a bilaterally symmetrical structure, the inner circumferential surface of the end nuts connected at both ends being provided with an internal thread; the air inlet and return pipe main body being a double-layer structure, the outer layer being a woven mesh made of stainless steel, and the inner layer being a fluoroplastic hose; end supports are respectively provided at the connection points between the two ends of the air inlet and return pipe main body and the end nuts, the end supports being used to connect the air inlet and return pipe main body and the end nuts; the length of the fluoroplastic hose at both ends slightly exceeds the woven mesh, and a flange structure is formed at the end support to form a sealing structure when the end nuts are threadedly connected to other components, thereby greatly reducing vibration while ensuring the flexibility of the air inlet and return pipe for the pulse tube refrigerator, and at the same time reducing gas flow resistance, thereby improving working efficiency and cooling capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of low-temperature refrigeration, and further to an air inlet and return pipe of a pulse tube refrigerator, and also to a pulse tube refrigerator having the air inlet and return pipe of the pulse tube refrigerator. Background Art

[0002] A pulse tube refrigerator is an ultra-low-temperature refrigerator that uses the filling and deflation of high- and low-pressure helium within a sealed pulse tube to achieve cooling in the liquid helium temperature range. Unlike a GM refrigerator, a pulse tube refrigerator lacks a reciprocating piston. Instead, it compresses the helium by forming a "gas-like piston" within the pulse tube. This results in minimal vibration, reduced wear and potential failures associated with moving parts, and a high degree of reliability. This makes it widely applicable in fields such as low-temperature superconductivity and quantum computing.

[0003] Pulse tube refrigerators (PTCs) are based on the principle of regenerative gas refrigeration, achieving cooling through a cyclical process of gas compression, expansion, and reheating. During operation, the gas distribution valve in the gas distribution assembly rotates. When it rotates to the inlet port, high-pressure helium from the helium compressor enters the pulse tube through the pulse tube's inlet and return pipes, where it expands. When the gas distribution valve rotates to the vent port, helium returns to the helium compressor through the pulse tube's inlet and return pipes. Thus, high and low pressure helium periodically alternates through the pulse tube's inlet and return pipes, which connect the gas distribution assembly to the regenerator. During the above working process, the pulse tube refrigerator's inlet and return pipes will vibrate due to the reciprocating motion of high- and low-pressure helium. In addition, since the current pulse tube refrigerator's inlet and return pipes generally use metal corrugated braided tubes, they will continuously switch back and forth between contraction and expansion during the pulse tube refrigerator's deflation and inflation process, causing the pulse tube refrigerator's inlet and return pipes to vibrate and create resistance to the helium flow, thereby causing the pulse tube refrigerator's inlet and return air to be unstable, affecting working efficiency. Summary of the Invention

[0004] The present invention aims to solve the aforementioned technical problems and thus provides a pulse tube refrigerator air inlet and return pipe. By improving the structure and materials of the pulse tube refrigerator air inlet and return pipe, the vibration and resistance of the pipe during operation of the pulse tube refrigerator are reduced, thereby improving the operating efficiency of the pulse tube refrigerator. The details are as follows:

[0005] A pulse tube refrigerator air inlet and return pipe, comprising an air inlet and return pipe main body and end nuts connected to both ends of the air inlet and return pipe main body, wherein the air inlet and return pipe main body is a bilaterally symmetrical structure; the characteristics are as follows: the air inlet and return pipe main body is a double-layer structure, the outer layer is a woven mesh made of stainless steel, and the inner layer is a fluoroplastic hose; end supports are respectively provided at the connection points between the two ends of the air inlet and return pipe main body and the end nuts, and the end supports act to connect the air inlet and return pipe main body and the end nuts; the length of the fluoroplastic hose at both ends slightly exceeds the woven mesh and a flange structure is formed at the end support to form a sealing structure when the end nut is threadedly connected to other components.

[0006] Furthermore, the end nuts at both ends of the inlet and return air pipe body are respectively connected to the self-sealing adapter and the air inlet adapter flange, and the self-sealing adapter is then connected to the self-sealing joint to realize the conversion between the self-sealing joint and the end nuts.

[0007] Furthermore, the end nut has a stepped cross-section symmetrically distributed along the axis of the inlet and return air pipe body, including a first inner circumferential surface with a smaller inner diameter and a second inner circumferential surface with a larger inner diameter, and a transition surface connecting the first inner circumferential surface with a smaller inner diameter and the second inner circumferential surface with a larger inner diameter and being perpendicular to both of them, wherein the first inner circumferential surface with a smaller inner diameter is sleeved and connected to the outer surface of the part of the fluoroplastic hose that exceeds the braided mesh, and the second inner circumferential surface with a larger inner diameter has an internal thread structure at least partially or completely.

[0008] Furthermore, the end support has an L-shaped cross-section symmetrically distributed along the axis of the inlet and return air pipe body, which includes a first support portion inserted between the first inner circumferential surface with a smaller inner diameter of the end nut and the outer surface of the fluoroplastic hose and a second support portion perpendicular to the first support portion; the second support portion has an annular support plane, and abuts against the transition surface of the end nut when the second inner circumferential surface with a larger inner diameter of the end nut is threadedly connected to the self-sealing adapter or the intake adapter flange.

[0009] Furthermore, the first supporting part of the end support is also connected to an end sleeve, and one end of the end sleeve is fixedly connected to the first supporting part of the end support by welding or integrally formed, thereby being inserted together between the first inner circumferential surface with a smaller inner diameter of the end nut and the outer surface of the fluoroplastic hose and thus sleeved on the outer surface of the fluoroplastic hose; the remaining part of the end sleeve is sleeved on the outer surface of the woven mesh, and because the woven mesh is located outside the fluoroplastic hose and has a certain thickness, the remaining part of the end sleeve is formed with a bent deformation section to tightly grasp the woven mesh and achieve compaction and fixation of it.

[0010] Furthermore, the fluoroplastic hose extends to the second support portion of the end support and forms a flange structure there, which is tightly fixed on the second support portion of the end support, thereby forming a sealing structure when the end nut is connected to the self-sealing adapter or the air intake adapter flange.

[0011] Furthermore, the material of the fluoroplastic hose is polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, fluorinated ethylene propylene copolymer, soluble polytetrafluoroethylene, polyvinylidene fluoride resin material or polyamide.

[0012] Furthermore, the fluoroplastic hose has a smooth inner wall and a corrugated outer wall.

[0013] The present invention also provides a pulse tube refrigerator, comprising a helium compressor, a gas distribution assembly and a refrigerator body. The refrigerator body comprises a primary heat regenerator and a secondary heat regenerator, and a primary pulse tube and a secondary pulse tube respectively connected to and working with the primary heat regenerator and the secondary heat regenerator. The primary pulse tube and the secondary pulse tube are respectively provided with a primary pulse tube gas reservoir and a secondary pulse tube gas reservoir. The aforementioned pulse tube refrigerator air inlet and return pipes are connected between the gas distribution assembly and the primary heat regenerator of the refrigerator body.

[0014] Furthermore, one end of the air inlet and return pipe body is connected to the air distribution assembly through the air inlet adapter flange, and the other end is connected to the self-sealing joint through the self-sealing adapter, and the self-sealing joint is then connected to the first-stage heat regenerator of the refrigerator body.

[0015] The pulse tube refrigerator air inlet and return pipes of the present invention replace the pulse tube refrigerator air inlet and return pipes of the prior art without significantly increasing the cost. The air inlet and return pipe body of the pulse tube refrigerator adopts a double-layer symmetrical structure, the outer layer of which uses a metal woven mesh, and the inner layer uses a fluoroplastic hose with a smooth inner wall and a corrugated outer wall. In addition, the flange structure of the fluoroplastic tube at both ends of the air inlet and return pipe body cooperates with the end nut and the end sleeve to form a sealed and fixed structure as a whole. While ensuring the flexibility of the pulse tube refrigerator air inlet and return pipes, it can greatly reduce vibration, reduce gas flow resistance, and improve the working efficiency and cooling capacity of the pulse tube refrigerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It is obvious that the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 : Schematic diagram of a conventional pulse tube refrigerator system;

[0018] Figure 2: A schematic diagram of the overall structure of the pulse tube refrigerator inlet and return pipes of the present invention;

[0019] Figure 3 : A front view of the air inlet and return pipes of the pulse tube refrigerator of the present invention;

[0020] Figure 4 : A cross-sectional view of the overall structure of the pulse tube refrigerator inlet and return pipes of the present invention;

[0021] Figure 5 : A partially enlarged schematic diagram of the pulse tube refrigerator inlet and return air pipes of the present invention.

[0022] Reference numerals:

[0023] 11-helium compressor; 12-gas distribution assembly; 13-refrigeration machine body; 14-first-stage regenerator; 15-second-stage regenerator; 17-first-stage pulse tube; 18-second-stage pulse tube; 19-first-stage pulse tube gas reservoir; 20-second-stage pulse tube gas reservoir; 21-inlet and return air pipes of pulse tube refrigerator; 22-inlet and return air pipe body; 23-self-sealing joint; 24-inlet adapter flange; 25-self-sealing adapter; 31-end nut; 311-transition surface; 312-first inner circumferential surface with smaller inner diameter; 313-second inner circumferential surface with larger inner diameter; 32-end support; 321-first support part; 322-second support part; 33-end sleeve; 331-bending deformation section; 34-fluoroplastic hose; 35-braided mesh; 36-flanged structure. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings of the present invention. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without expending creative work are within the scope of protection of the present invention.

[0025] Figure 1 The figure shows a conventional pulse tube refrigerator system in the art. Figure 1As shown, the pulse tube refrigerator comprises a helium compressor 11, a gas distribution assembly 12, and a refrigerator body 13. The refrigerator body 13 includes a primary regenerator 14 and a secondary regenerator 15, as well as a primary pulse tube 17 and a secondary pulse tube 18, which are connected to and operative with the primary regenerator 14 and the secondary regenerator 15, respectively. The primary pulse tube 17 and the secondary pulse tube 18 are provided with a primary pulse tube gas reservoir 19 and a secondary pulse tube gas reservoir 20, respectively. During operation, the helium compressor 11 operates periodically. The rotation of a rotary valve (not shown) in the gas distribution assembly 12 causes high and low pressure helium to alternately pass through the pulse tube refrigerator inlet and return gas pipes 21, which are connected between the gas distribution assembly 12 and the primary regenerator 14 of the refrigerator body 13. The pulse tube refrigerator's inlet and return air pipes 21 vibrate due to the alternating movement of high- and low-pressure helium. Furthermore, since the conventional pulse tube refrigerator's inlet and return air pipes 21 generally use metal corrugated braided tubes, they continuously switch back and forth between contraction and expansion during the pulse tube refrigerator's deflation and inflation process, causing the pulse tube refrigerator's inlet and return air pipes 21 to vibrate and create resistance to the helium flow, thereby causing instability in the inlet and return air, affecting the pulse tube refrigerator's operating efficiency and cooling capacity.

[0026] In order to solve the above problems, the present invention proposes a new structure of the pulse tube refrigerator inlet and return air pipe 21, the overall structure of which is shown in the three-dimensional diagram. Figure 2 As shown, it includes an air inlet and return pipe body 22, and end nuts 31 are connected to both ends of the air inlet and return pipe body 22. The end nuts 31 at both ends are respectively connected to a self-sealing adapter 25 and an air inlet adapter flange 24. The self-sealing adapter 25 is also connected to a self-sealing joint 23, which is used to achieve the connection between the self-sealing joint 23 and the air inlet and return pipe body 22. Figure 3 As shown in the front view of the pulse tube refrigerator's inlet and return pipes 21, the inlet and return pipe body 22 has a bilaterally symmetrical structure. Two end nuts 31 are respectively mounted and connected to the two ends of the inlet pipe body 22. The end nuts 31 at both ends are respectively connected to the self-sealing adapter 25 and the inlet adapter flange 24. The inlet adapter flange 24 is connected to the gas distribution assembly 12, thereby achieving communication with the helium compressor 11. The self-sealing adapter 25 is connected to the self-sealing joint 23, thereby achieving connection with the primary regenerator 14 of the refrigerator body 13. When the rotary valve in the gas distribution assembly 12 rotates to the inlet hole, high-pressure helium from the helium compressor 11 passes through the pulse tube refrigerator's inlet and return pipes 21 and enters the primary regenerator 14. When the rotary valve in the gas distribution assembly 12 rotates to the vent hole, the helium returns from the pulse tube refrigerator's inlet and return pipes 21 to the helium compressor 11.

[0027] The detailed structure of the pulse tube refrigerator inlet and return pipe 21 is as follows: Figure 4 and 5As shown, the main body 22 of the air inlet and return pipes is a double-layer structure, the outer layer is made of a woven mesh 35 made of stainless steel, and the inner layer is made of a fluoroplastic hose 34 with a smooth inner wall, a corrugated outer wall and acid and alkali resistance. The length of the fluoroplastic hose 34 at both ends slightly exceeds the woven mesh 35 to facilitate connection with the end nut 31. The end nut 31 has a stepped cross-section symmetrically distributed along the axis of the air inlet / return pipe body 22. Specifically, it comprises a first inner circumferential surface 312 with a smaller inner diameter, a second inner circumferential surface 313 with a larger inner diameter, and a transition surface 311 connecting and perpendicular to the first and second inner circumferential surfaces 312 and 313. The first inner circumferential surface 312 with a smaller inner diameter is sleeved and connected to the outer surface of the fluoroplastic hose 34 within the air inlet / return pipe body 22, extending beyond the outer braided mesh 35. The second inner circumferential surface 313 with a larger inner diameter is at least partially or entirely internally threaded for threaded connection and locking with the self-sealing adapter 25 and the air inlet adapter flange 24, respectively. The double-layered air inlet / return pipe body 22 is further provided with end supports 32 at the junctions between the end nut 31 and the end nut 31 on both sides. The end supports 32 serve to connect the air inlet / return pipe body 22 and the end nut 31.

[0028] More specifically, if Figure 5As shown in a partially enlarged schematic diagram of the pulse tube refrigerator's inlet and return air pipe 21, the end support 32 has an L-shaped cross-section symmetrically distributed along the axis of the inlet and return air pipe body 22. It is disposed between the end nut 31 and the end of the inlet and return air pipe body 22 and includes a first support portion 321 inserted between the first inner circumferential surface 312 (with a smaller inner diameter) of the end nut 31 and the outer surface of the fluoroplastic hose 34, and a second support portion 322 perpendicular to the first support portion 321. The second support portion 322 has an annular support surface and, when the second inner circumferential surface 313 (with a larger inner diameter) of the end nut 31 is threadedly connected to the self-sealing adapter 25 or the inlet adapter flange 24, abuts against the transition surface 311 of the end nut 31, that is, the transition surface 311 between the first inner circumferential surface 312 (with a smaller inner diameter) and the second inner circumferential surface 313 (with a larger inner diameter) of the end nut 31. The first support portion 321 of the end support 32 is also connected to an end sleeve 33. One end of the end sleeve 33 is fixedly connected to the first support portion 321 of the end support 32 by welding or integrally formed. The sleeve 33 is inserted between the first inner circumferential surface 312 of the end nut 31 (with a smaller inner diameter) and the outer surface of the fluoroplastic hose 34, thereby being fitted over the outer surface of the fluoroplastic hose 34. The remaining portion of the end sleeve 33 is fitted over the outer surface of the braided mesh 35. Because the braided mesh 35 is located outside the fluoroplastic hose 34 and has a certain thickness, the remaining portion of the end sleeve 33 forms a bent and deformed section 331 that tightly grips the braided mesh 35 and achieves compaction and fixation. The fluoroplastic hose 34 extends to the second support portion 322 of the end support 32 and forms a flange structure 36 there. The flange structure 36 is tightly fixed to the second support portion 322 of the end support 32 through a vulcanization process, thereby forming a seal when the end nut 31 is connected to the self-sealing adapter 25 and the intake adapter flange 24.

[0029] Based on the above-described specific embodiments, the pulse tube refrigerator inlet and return pipe 21 of the present invention replaces the conventional pulse tube refrigerator inlet and return pipe 21 without significantly increasing costs. The inlet and return pipe body 22 of the pulse tube refrigerator 21 adopts a symmetrical double-layer structure, with an outer layer made of a metal braided mesh 35 and an inner layer made of a fluoroplastic hose 34 with a smooth inner wall and a corrugated outer wall. The flanged edges 36 of the fluoroplastic hose 34 at both ends of the inlet and return pipe body 22 cooperate with the end nuts 31 and end sleeves 33 to form a sealed and fixed structure. This ensures the flexibility of the pulse tube refrigerator inlet and return pipe 21 while significantly reducing vibration and gas flow resistance, thereby improving the efficiency and cooling capacity of the pulse tube refrigerator. Furthermore, the fluoroplastic hose 34 can be made of PTFE (polytetrafluoroethylene), ETFE (ethylene-tetrafluoroethylene copolymer), FEP (fluorinated ethylene propylene copolymer), PFA (soluble polytetrafluoroethylene), or PVDF (polyvinylidene fluoride resin). PA (polyamide) hose can also be used instead.

[0030] The above detailed description of the pulse tube cooler inlet and return air ducts provided by the present invention has been provided. Specific examples have been used to illustrate the principles and implementations of the present invention. The above examples are intended only to facilitate understanding of the present invention's methods and core concepts. For those skilled in the art, the technical solutions of the present invention are not limited to the specific implementations described. Other variations that are readily achievable based on common technical knowledge in the field are also within the scope of protection of the present invention.

Claims

1. A pulse tube refrigerator air inlet and return pipe, comprising an air inlet and return pipe body (22) and end nuts (31) connected to both ends of the air inlet and return pipe body (22), wherein the air inlet and return pipe body (22) is a bilaterally symmetrical structure; characterized in that: The air inlet and return pipe body (22) is a double-layer structure, the outer layer is made of a braided mesh (35) made of stainless steel, and the inner layer is made of a fluoroplastic hose (34); end supports (32) are respectively provided at the connection points between the two ends of the air inlet and return pipe body (22) and the end nut (31), and the end supports (32) act to connect the air inlet and return pipe body (22) and the end nut (31); the length of the fluoroplastic hose (34) at both ends is slightly longer than the braided mesh (35) and a flange structure (36) is formed at the end support (32) to form a sealing structure when the end nut (31) is threadedly connected to other components; the end nut ( 31) having a stepped cross-section symmetrically distributed along the axis of the air inlet and return pipe body (22), including a first inner circumferential surface (312) with a smaller inner diameter and a second inner circumferential surface (313) with a larger inner diameter, and a transition surface (311) connecting the first inner circumferential surface (312) with a smaller inner diameter and the second inner circumferential surface (313) with a larger inner diameter and being perpendicular to both, wherein the first inner circumferential surface (312) with a smaller inner diameter is sleeved and connected to the outer surface of the portion of the fluoroplastic hose (34) exceeding the braided mesh (35), and the second inner circumferential surface (313) with a larger inner diameter at least partially or entirely has an internal thread structure; The end support (32) has an L-shaped cross-section symmetrically distributed along the axis of the air inlet and return pipe body (22), and includes a first support portion (321) inserted between a first inner circumferential surface (312) with a smaller inner diameter of the end nut (31) and the outer surface of the fluoroplastic hose (34), and a second support portion (322) perpendicular to the first support portion (321); the second support portion (322) has an annular support plane and abuts against a transition surface (311) of the end nut (31) when the second inner circumferential surface (313) with a larger inner diameter of the end nut (31) is threadedly connected to the self-sealing adapter (25) or the air inlet adapter flange (24); The first support portion (321) of the end support (32) is also connected to the end sleeve (33), and one end of the end sleeve (33) is fixedly connected to the first support portion (321) of the end support (32) by welding or integrally formed, thereby being inserted together between the first inner circumferential surface (312) with a smaller inner diameter of the end nut (31) and the outer surface of the fluoroplastic hose (34) and thus sleeved on the outer surface of the fluoroplastic hose (34); the remaining portion of the end sleeve (33) is sleeved on the outer surface of the braided mesh (35), and because the braided mesh (35) is located outside the fluoroplastic hose (34) and has a certain thickness, the remaining portion of the end sleeve (33) is formed with a bent deformation section (331) to tightly clasp the braided mesh (35) and achieve compaction and fixation thereof; The fluoroplastic hose (34) extends to the second support portion (322) of the end support (32) and forms a flange structure (36) there. The flange structure (36) is tightly fixed on the second support portion (322) of the end support (32), thereby forming a sealing structure when the end nut (31) is connected to the self-sealing adapter (25) or the air inlet adapter flange (24).

2. The pulse tube refrigerator air inlet and return pipe according to claim 1, characterized in that: The end nuts (31) at both ends of the air inlet and return pipe body (22) are respectively threadedly connected to the self-sealing adapter (25) and the air inlet adapter flange (24), and the self-sealing adapter (25) is further connected to the self-sealing connector (23).

3. The pulse tube refrigerator air inlet and return pipe according to any one of claims 1 to 2, characterized in that: The material of the fluoroplastic hose (34) is polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, fluorinated ethylene propylene copolymer, soluble polytetrafluoroethylene, polyvinylidene fluoride resin material or polyamide.

4. The pulse tube refrigerator air inlet and return pipe according to any one of claims 1 to 2, characterized in that: The fluoroplastic hose (34) has a smooth inner wall and a corrugated outer wall.

5. A pulse tube refrigerator, comprising a helium compressor (11), an air distribution assembly (12) and a refrigerator body (13), wherein the refrigerator body (13) comprises a primary regenerator (14) and a secondary regenerator (15), and a primary pulse tube (17) and a secondary pulse tube (18) respectively connected to and working with the primary regenerator (14) and the secondary regenerator (15), wherein the primary pulse tube (17) and the secondary pulse tube (18) are respectively provided with a primary pulse tube gas reservoir (19) and a secondary pulse tube gas reservoir (20), and the pulse tube refrigerator inlet and return gas pipe according to any one of claims 1 to 4 is connected between the air distribution assembly (12) and the primary regenerator (14) of the refrigerator body (13).

6. The pulse tube refrigerator according to claim 5, wherein: One end of the air inlet and return pipe body (22) is connected to the air distribution assembly (12) through the air inlet adapter flange (24), and the other end is connected to the self-sealing joint (23) through the self-sealing adapter (25). The self-sealing joint (23) is then connected to the first-stage regenerator (14) of the refrigerator body (13).

Images