Air inlet and return pipe of pulse tube refrigerator

Abstract

The air inlet and return pipe comprises an air inlet and return pipe body and end nuts connected to the two ends of the air inlet and return pipe body, the air inlet and return pipe body is of a bilateral symmetry structure, and internal threads are arranged on the inner circumferential surfaces of the end nuts connected to the two ends; the air inlet and return pipe body is of 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 arranged at the joints of the two ends of the air inlet and return pipe main body and the end nuts, and are used for connecting the air inlet and return pipe main body and the end nuts; the length of the end portions of the two sides of the fluoroplastic hose is slightly larger than that of the woven mesh, and a turnup structure is formed at the end supporting position so that a sealing structure can be formed when the end nut is in threaded connection with other parts, the flexibility of the air inlet and return pipe of the pulse tube refrigerator is guaranteed, vibration can be greatly reduced, meanwhile, gas flow resistance is reduced, and working efficiency and refrigerating capacity are improved.

Description

Technical Field

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

[0002] A pulse tube refrigerator is a cryogenic refrigerator that uses the charging and discharging process of high-pressure and low-pressure helium gas in a closed pulse tube to achieve a refrigeration effect in the liquid helium temperature range. Compared with a GM refrigerator, the pulse tube refrigerator has no reciprocating piston. It relies on the "gas piston" formed by helium gas in the pulse tube to compress the helium gas. Therefore, it has small vibration and reduces the wear and potential failure hazards caused by moving parts, and has high reliability. It can be widely used in fields such as cryogenic superconductivity and quantum computing.

[0003] The pulse tube refrigerator is based on the regenerative gas refrigeration principle and realizes refrigeration through periodic gas compression, expansion, and regeneration processes. During operation, with the rotational movement of the gas distribution valve in the gas distribution assembly, when it rotates to the intake hole, the high-pressure helium gas coming from the helium compressor enters the pulse tube through the inlet and return air pipe of the pulse tube refrigerator for expansion; when the gas distribution valve in the gas distribution assembly rotates to the exhaust hole, the helium gas returns to the helium compressor through the inlet and return air pipe of the pulse tube refrigerator. Thus, the high-pressure and low-pressure helium gas alternately passes through the inlet and return air pipe of the pulse tube refrigerator connecting the gas distribution assembly and the regenerator periodically. In the above working process, the inlet and return air pipe of the pulse tube refrigerator will vibrate due to the reciprocating movement of the high-pressure and low-pressure helium gas. And because the currently commonly used inlet and return air pipe of the pulse tube refrigerator is a metal corrugated braided pipe, during the gas discharge and charging processes of the pulse tube refrigerator, it will continuously switch back and forth between the contracted and expanded states, resulting in vibration of the inlet and return air pipe of the pulse tube refrigerator and generating resistance to the helium gas flow, thereby causing unstable inlet and return air of the pulse tube refrigerator and affecting the working efficiency. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems discussed above, and thus provide an inlet and return air pipe of a pulse tube refrigerator, which reduces its vibration and resistance during the operation of the pulse tube refrigerator by improving the composition structure and materials of the inlet and return air pipe of the pulse tube refrigerator, thereby improving the working efficiency of the pulse tube refrigerator. Specifically as follows:

[0005] A suction and discharge pipe for a pulse tube refrigerator, comprising a suction and discharge pipe main body and end nuts connected to both ends of the suction and discharge pipe main body, and the suction and discharge pipe main body is a left-right symmetric structure; characterized in that: the suction and discharge pipe main body is a double-layer structure, the outer layer is a braided net made of stainless steel material, and the inner layer is a fluoroplastic hose; end supports are respectively arranged at the connections between both ends of the suction and discharge pipe main body and the end nuts, and the end supports function to connect the suction and discharge pipe main body and the end nuts; the length of the fluoroplastic hose at both ends slightly exceeds that of the braided net and forms a flanging structure at the end supports to form a sealing structure when the end nuts are threadedly connected to other components.

[0006] Further, self-sealing adapters and air inlet adapter flanges are respectively connected to the end nuts at both ends of the suction and discharge pipe main body, and the self-sealing adapters are further connected to self-sealing joints to realize the transfer between the self-sealing joints and the end nuts.

[0007] Further, the end nuts have a stepped cross-section symmetrically distributed along the axis of the suction and discharge pipe main body, including a first inner circumferential surface with a smaller inner diameter, 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 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 net, and at least part or all of the second inner circumferential surface with a larger inner diameter has an internal thread structure.

[0008] Further, the end supports have an L-shaped cross-section symmetrically distributed along the axis of the suction and discharge pipe main body, which includes a first support part 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 part perpendicular to the first support part; the second support part 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 air inlet adapter flange.

[0009] Further, an end sleeve is also connected to the first support part of the end support, and one end of the end sleeve is fixedly connected to the first support part of the end support by welding or integrally formed, and thus is 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 braided net, and since the braided net is located outside the fluoroplastic hose and has a certain thickness, the remaining part of the end sleeve forms a bent and deformed section to tightly hold the braided net and realize its compaction and fixation.

[0010] Further, the fluoroplastic hose extends to the second support portion of the end support and forms a flanging structure here. The flanging structure is closely 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 intake adapter flange.

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

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

[0013] The present invention also provides a pulse tube refrigerator, which includes a helium compressor, a gas distribution assembly and a refrigerator main body. The refrigerator main body includes a first-stage regenerator and a second-stage regenerator, and a first-stage pulse tube and a second-stage pulse tube that are respectively communicated with and operate on the first-stage regenerator and the second-stage regenerator. The first-stage pulse tube and the second-stage pulse tube are respectively provided with a first-stage pulse tube gas reservoir and a second-stage pulse tube gas reservoir. The aforementioned pulse tube refrigerator inlet and return air pipe is connected between the gas distribution assembly and the first-stage regenerator of the refrigerator main body.

[0014] Further, one end of the inlet and return air pipe main body is communicated with the gas distribution assembly through an intake adapter flange, and the other end is connected to a self-sealing joint through a self-sealing adapter, and the self-sealing joint is further communicated with the first-stage regenerator of the refrigerator main body.

[0015] The pulse tube refrigerator inlet and return air pipe of the present invention replaces the pulse tube refrigerator inlet and return air pipe of the prior art without significantly increasing the cost. The inlet and return air pipe main body of the pulse tube refrigerator inlet and return air pipe adopts a double-layer symmetric structure. Its outer layer uses a metal braided net, and its inner layer uses a fluoroplastic hose with a smooth inner wall and a corrugated structure on the outer wall. And both ends of the inlet and return air pipe main body use the flanging structure of the fluoroplastic pipe to cooperate with the end nut and the end sleeve and form a sealed fixed structure as a whole. While ensuring the flexibility of the pulse tube refrigerator inlet and return air pipe, it can greatly reduce vibration, reduce gas flow resistance at the same time, and improve the working efficiency and refrigeration 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 will briefly introduce the drawings required in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

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

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

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

[0020] Figure 4 : Overall structure sectional view of the inlet and return air pipes of the pulse tube refrigerator of the present invention;

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

[0022] Reference numerals in the drawings:

[0023] 11 - Helium compressor; 12 - Gas distribution assembly; 13 - Refrigerator main body; 14 - First regenerator; 15 - Second regenerator; 17 - First pulse tube; 18 - Second pulse tube; 19 - First pulse tube gas reservoir; 20 - Second pulse tube gas reservoir; 21 - Inlet and return air pipes of the pulse tube refrigerator; 22 - Main body of the inlet and return air pipes; 23 - Self-sealing joint; 24 - Inlet transfer flange; 25 - Self-sealing adapter; 31 - End nut; 311 - Transition surface; 312 - First inner circumferential surface with a smaller inner diameter; 313 - Second inner circumferential surface with a larger inner diameter; 32 - End support; 321 - First support part; 322 - Second support part; 33 - End sleeve; 331 - Bent and deformed section; 34 - Fluoroplastic hose; 35 - Braided mesh; 36 - Flanging structure. Detailed implementation manners

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] Figure 1 The following shows a schematic diagram of a conventional pulse tube refrigerator system in the art, as Figure 1As shown in the figure, the pulse tube refrigerator includes a helium compressor 11, a gas distribution component 12, and a refrigerator main body 13. The refrigerator main body 13 includes a first-stage regenerator 14, a second-stage regenerator 15, a first-stage pulse tube 17 and a second-stage pulse tube 18 that are respectively communicated with and operate with the first-stage regenerator 14 and the second-stage regenerator 15. The first-stage pulse tube 17 and the second-stage pulse tube 18 are respectively provided with a first-stage pulse tube gas reservoir 19 and a second-stage pulse tube gas reservoir 20. When the pulse tube refrigerator is operating, the helium compressor 11 works periodically. Through the rotational movement of a rotary valve (not shown) in the gas distribution component 12, high-pressure and low-pressure helium gas alternately passes through the inlet and return gas pipe 21 of the pulse tube refrigerator connected between the gas distribution component 12 and the first-stage regenerator 14 of the refrigerator main body 13. Due to the reciprocating alternating movement of the high-pressure and low-pressure helium gas, the inlet and return gas pipe 21 of the pulse tube refrigerator will vibrate. And because the inlet and return gas pipe 21 of the pulse tube refrigerator in the prior art generally uses a metal corrugated braided pipe, during the gas release and gas filling processes of the pulse tube refrigerator, it will continuously switch back and forth between the contracted and expanded states, resulting in the vibration of the inlet and return gas pipe 21 of the pulse tube refrigerator and generating resistance to the helium gas flow, thereby causing unstable inlet and return gas, affecting the working efficiency and refrigerating capacity of the pulse tube refrigerator.

[0026] To solve the above problems, the present invention proposes an inlet and return gas pipe 21 with a new structure. Its overall structure three-dimensional diagram is as Figure 2 shown, including an inlet and return gas pipe main body 22. End nuts 31 are respectively connected to both ends of the inlet and return gas pipe main body 22. The end nuts 31 at both ends are respectively connected to a self-sealing adapter 25 and an intake adapter flange 24. The self-sealing adapter 25 is also connected to a self-sealing joint 23 for realizing the transfer between the self-sealing joint 23 and the inlet and return gas pipe main body 22. As Figure 3 shown in the front view of the inlet and return gas pipe 21 of the pulse tube refrigerator, the inlet and return gas pipe main body 22 is a left-right symmetric structure. The two end nuts 31 are respectively sleeved and connected to both ends of the intake pipe main body 22. The end nuts 31 at both ends are respectively connected to the self-sealing adapter 25 and the intake adapter flange 24. The intake adapter flange 24 is connected to the gas distribution component 12, thereby realizing the connection with the helium compressor 11. The self-sealing adapter 25 is connected to the self-sealing joint 23, thereby realizing the connection with the first-stage regenerator 14 of the refrigerator main body 13. When the rotary valve in the gas distribution component 12 rotates to the intake hole, the high-pressure helium gas coming from the helium compressor 11 enters the first-stage regenerator 14 through the inlet and return gas pipe 21 of the pulse tube refrigerator; when the rotary valve in the gas distribution component 12 rotates to the gas release hole, the helium gas returns to the helium compressor 11 from the inlet and return gas pipe 21 of the pulse tube refrigerator.

[0027] The more detailed structure of the inlet and return gas pipe 21 of the pulse tube refrigerator is as Figure 4 and 5As shown, the inlet and return air pipe body 22 has 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 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 braided mesh 35 for easy connection with the end nuts 31. The end nuts 31 have a stepped cross-section symmetrically distributed along the axis of the inlet and return air pipe body 22, that is, actually including 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 the first inner circumferential surface 312 with a smaller inner diameter and the second inner circumferential surface 313 with a larger inner diameter and perpendicular to both of them. The first inner circumferential surface 312 with a smaller inner diameter is sleeved and connected to the outer surface of the part of the fluoroplastic hose 34 of the inner layer of the inlet and return air pipe body 22 that exceeds the braided mesh 35 of the outer layer. The second inner circumferential surface 313 with a larger inner diameter has at least part or all of an internal thread structure to be threadedly connected and locked with the self-sealing adapter 25 and the air inlet adapter flange 24 respectively. At the connection between the double-layer inlet and return air pipe body 22 and the end nuts 31 at both ends, end supports 32 are further provided. The end supports 32 function to connect the inlet and return air pipe body 22 and the end nuts 31.

[0028] More specifically, as Figure 5As shown in the partial enlarged schematic view of the inlet and return air pipes 21 of the pulse tube refrigerator, 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 arranged 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 plane and abuts against the transition surface 311 of the end nut 31 when threadedly connected to the self-sealing adapter 25 or the intake adapter flange 24, that is, it abuts against 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. A end sleeve 33 is also connected to the first support portion 321 of the end support 32. 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, and thus is also 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 is sleeved on the outer surface of the fluoroplastic hose 34; the remaining part 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 part of the end sleeve 33 forms a bent deformation section 331 to tightly hold the braided mesh 35 and realize its compaction and fixation. The fluoroplastic hose 34 extends to the second support portion 322 of the end support 32 and forms a flanging structure 36 here. The flanging structure 36 is tightly fixed on the second support portion 322 of the end support 32 by vulcanization process, thereby forming a sealing structure when the end nut 31 is connected to the self-sealing adapter 25 and the intake adapter flange 24.

[0029] Based on the above specific embodiments, the inlet and return gas pipes 21 of the pulse tube refrigerator of the present invention replace the inlet and return gas pipes 21 of the prior art without significantly increasing the cost. The inlet and return gas pipe body 22 of the inlet and return gas pipes 21 of the pulse tube refrigerator adopts a double-layer symmetrical structure. Its outer layer uses a metal braided net 35, and its inner layer uses a fluoroplastic hose 34 with a smooth inner wall and a corrugated outer wall. Moreover, both ends of the inlet and return gas pipe body 22 utilize the flanging structure 36 of the fluoroplastic hose 34 to cooperate with the end nut 31 and the end sleeve 33 to form a sealed fixed structure as a whole. While ensuring the flexibility of the inlet and return gas pipes 21 of the pulse tube refrigerator, it can significantly reduce vibration, simultaneously reduce the gas flow resistance, and improve the working efficiency and refrigerating capacity of the pulse tube refrigerator. Further, the material of the fluoroplastic hose 34 can be PTFE (polytetrafluoroethylene), ETFE (ethylene-tetrafluoroethylene copolymer), FEP (fluorinated ethylene propylene copolymer), PFA (soluble polytetrafluoroethylene), or PVDF (polyvinylidene fluoride resin) material, or a PA (polyamide) hose can also be used instead.

[0030] The above has introduced in detail a kind of inlet and return gas pipes of a pulse tube refrigerator provided by the present invention. Specific examples are used herein to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. For those of ordinary skill in the art, the technical solution of the present invention is not limited to the solution defined by the specific implementation manner. The technical solutions formed by other obvious changes that can be achieved according to the general technical knowledge in this field are all within the protection scope of the present invention.

Claims

1. A suction and discharge pipe of a pulse tube refrigerator, comprising a suction and discharge pipe main body (22) and end nuts (31) connected to both ends of the suction and discharge pipe main body (22), the suction and discharge pipe main body (22) being a left-right symmetric structure; characterized in that: The inlet and return air pipe body (22) has a double-layer structure. The outer layer is a braided mesh (35) made of stainless steel, and the inner layer is a fluoroplastic hose (34); at the connections between the two ends of the inlet and return air pipe body (22) and the end nuts (31), end supports (32) are respectively provided. The end supports (32) function to connect the inlet and return air pipe body (22) and the end nuts (31); the fluoroplastic hose (34) is slightly longer than the braided mesh (35) at both ends and forms a flanging structure (36) at the end supports (32) to form a sealing structure when the end nuts (31) are threadedly connected to other components.

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

3. The inlet and return air pipes of the pulse tube refrigerator according to claim 1, characterized in that: The end nut (31) has a stepped cross-section symmetrically distributed along the axis of the inlet and return air pipe body (22), including 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 the first inner circumferential surface (312) with a smaller inner diameter and the second inner circumferential surface (313) with a larger inner diameter and perpendicular to both of them. Among them, the first inner circumferential surface (312) with a smaller inner diameter is sleeved and connected to the outer surface of the part of the fluoroplastic hose (34) that exceeds the braided mesh (35), and at least part or all of the second inner circumferential surface (313) with a larger inner diameter has an internal thread structure.

4. The inlet and return air pipes of the pulse tube refrigerator according to claim 2, characterized in that: The end support (32) has an L-shaped cross-section symmetrically distributed along the axis of the inlet and return air pipe body (22), which includes a first support part (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 part (322) perpendicular to the first support part (321); the second support part (322) has an annular support plane and abuts against the 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).

5. The inlet and return air pipes of the pulse tube refrigerator according to claim 4, characterized in that: The first support part (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 part (321) of the end support (32) by welding or integrally formed, and thus they are 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 part of the end sleeve (33) is sleeved on the outer surface of the braided mesh (35), and since the braided mesh (35) is located outside the fluoroplastic hose (34) and has a certain thickness, the remaining part of the end sleeve (33) forms a bent and deformed section (331) to tightly hold the braided mesh (35) and realize its compaction and fixation.

6. The inlet and return air pipes of the pulse tube refrigerator according to claim 5, characterized in that: The fluoroplastic hose (34) extends to the second support part (322) of the end support (32) and forms a flanging structure (36) here. The flanging structure (36) is closely fixed on the second support part (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).

7. The inlet and return air pipes of the pulse tube refrigerator according to any one of claims 1 to 6, 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.

8. The inlet and return air pipes of the pulse tube refrigerator according to any one of claims 1 to 6, characterized in that: The fluoroplastic hose (34) has a smooth inner wall and a corrugated outer wall.

9. A pulse tube refrigerator, comprising a helium compressor (11), a gas distribution assembly (12) and a refrigerator main body (13). The refrigerator main body (13) includes a first-stage regenerator (14) and a second-stage regenerator (15), and a first-stage pulse tube (17) and a second-stage pulse tube (18) that are respectively communicated with and operate with the first-stage regenerator (14) and the second-stage regenerator (15). The first-stage pulse tube (17) and the second-stage pulse tube (18) are respectively provided with a first-stage pulse tube gas reservoir (19) and a second-stage pulse tube gas reservoir (20). A pulse tube refrigerator inlet and return air pipe according to any one of claims 1-8 is connected between the gas distribution assembly (12) and the first-stage regenerator (14) of the refrigerator main body (13).

10. The pulse tube refrigerator according to claim 9, characterized in that: One end of the inlet and return air pipe main body (22) is communicated with the gas 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 communicated with the first-stage regenerator (14) of the refrigerator main body (13).

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