Expansion machine air inlet structure for Stirling cryocooler and Stirling cryocooler

Abstract

The invention provides an expansion machine air inlet structure for a Stirling cryocooler and the Stirling cryocooler. The air inlet structure comprises a pushing piston, and the pushing piston comprises a rod part and a plug part; a plug part of the pushing piston comprises a plurality of inclined round hole air passages, a plurality of first slit type air passages communicated with the inclined round hole air passages are arranged at one end, far away from a rod part, of the plug part, and the plurality of first slit type air passages are uniformly distributed around a central shaft of the pushing piston and are intersected at the central shaft of the pushing piston; the end face, away from the rod part, of the plug part is provided with a conical concave face at the intersection of the first slit type air channels. The pushing piston is connected with a hot end of a heat regenerator; the cold end of the heat regenerator is provided with a plurality of second slit type air channels, and the second slit type air channels are evenly distributed around the center axis of the heat regenerator and intersect at the center axis of the heat regenerator. The device is simple in structure and easy to machine; the laminar flow state of a working medium at the cold end and the hot end of the heat regenerator can be effectively enhanced, flow resistance and eddy current loss are reduced, and refrigerating efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of Stirling refrigerators, and in particular to an expander air intake structure for a Stirling refrigerator and a Stirling refrigerator. Background Art

[0002] As a highly efficient and environmentally friendly refrigeration equipment, Stirling refrigerators are increasingly used in aerospace, security, gas leak detection and other fields with the rapid development of infrared detector components. They are one of the most important technical products in infrared detector components. The working principle of Stirling refrigerators is based on the Stirling cycle, which achieves the refrigeration effect through the compression and expansion process of gas; among them, the regenerator is one of the most important moving parts in the Stirling refrigerator, and the energy loss accounts for more than 60% of the entire refrigerator. Its heat recovery efficiency plays a vital role in the refrigeration performance.

[0003] In the Stirling refrigerator in the related technology, the regenerator is usually filled with heat exchange materials such as stainless steel wire mesh. The pressure wave provided by the compressor drives the working fluid to oscillate back and forth between the hot and cold ends inside the regenerator, exchanging heat with the regenerator filler to produce a cooling effect. When the working fluid shuttles through the regenerator, there will be a large flow resistance loss. On the one hand, it is caused by the interaction with the regenerator wire mesh, and on the other hand, it is the eddy current loss generated by the regenerator structure when the working fluid enters and exits the regenerator. The above two aspects will affect the overall refrigeration performance of the refrigerator, increase power consumption, and prolong the cooling time to reach the required low temperature state. Summary of the invention

[0004] The invention provides an expander air intake structure for a Stirling refrigerator and a Stirling refrigerator, which solves the problem of how to reduce the energy loss of the Stirling refrigerator and improve the refrigeration efficiency.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect, an expander air intake structure for a Stirling refrigerator is provided, comprising:

[0007] a pneumatic chamber for accommodating the piston assembly and the regenerator;

[0008] The piston assembly comprises a push piston and a push piston cylinder sleeve;

[0009] The push piston comprises a rod portion and a plug portion;

[0010] The plugging portion of the push piston comprises a plurality of inclined circular hole air passages evenly distributed around the central axis of the push piston, and the plurality of inclined circular hole air passages extend along the end surface of the plugging portion close to the rod portion into the plugging portion and intersect at the set position of the central axis of the push piston; the end of the plugging portion away from the rod portion is provided with a plurality of first slit-type air passages connected with the inclined circular hole air passages, and the plurality of first slit-type air passages are evenly distributed around the central axis of the push piston and intersect at the central axis of the push piston; the end surface of the plugging portion away from the rod portion is provided with a conical concave surface at the intersection of the plurality of first slit-type air passages;

[0011] The push piston is fixedly connected to the hot end of the heat regenerator; a plurality of second slit air ducts are arranged at the cold end of the heat regenerator, and the plurality of second slit air ducts are evenly distributed around the central axis of the heat regenerator and intersect at the central axis of the heat regenerator.

[0012] In a first possible implementation of the first aspect, the push piston cylinder sleeve includes a piston cavity for accommodating the push piston; the push piston cylinder sleeve is sleeved on the rod portion of the push piston and the plugging portion of the push piston is placed in the piston cavity to form a piston structure; one end of the push piston away from the plugging portion extends to the outside of the piston cavity and is fixedly connected with an elastic member for providing a reset force for the push piston; the piston cavity is provided with a first air channel for communicating with the pneumatic chamber; the pneumatic chamber is provided with a second air channel for connecting a connecting pipe, and the connecting pipe is used to be connected to a compressor to provide a driving force for the push piston.

[0013] Based on any possible implementation of the first aspect, in a second possible implementation of the first aspect, the slit width, length and number of the first slit air duct and the second slit air duct are determined according to the required cooling capacity and efficiency of the refrigerator.

[0014] In a third possible implementation manner of the first aspect, the number of the inclined circular hole airways is 4.

[0015] In a fourth possible implementation manner of the first aspect, the hot end of the heat regenerator is connected to the plugging portion of the push piston by adhesive.

[0016] Based on the first possible implementation of the first aspect, in a fifth possible implementation of the first aspect, the elastic member is configured as a spring, the push piston cylinder sleeve and the spring are connected by laser welding, and the spring and the rod portion of the push piston are connected by threads and thread glue.

[0017] In a sixth possible implementation manner of the first aspect, the pneumatic chamber includes an openable and closable pneumatic chamber end cover.

[0018] In a second aspect, a Stirling refrigerator is provided, comprising the expander air intake structure for the Stirling refrigerator as described in the first aspect.

[0019] In a third aspect, an infrared device is provided, comprising the Stirling refrigerator as described in the second aspect.

[0020] The present application has a simple structure and is easy to process; only the structure of the regenerator and the hot-end push piston plug is changed, which will not affect the original assembly relationship and sequence of the refrigerator. It can effectively enhance the laminar flow state of the working fluid at the inlet and outlet of the cold-end and hot-end push piston plugs of the regenerator, reduce flow resistance loss and eddy current loss, and improve the refrigeration efficiency of the Stirling refrigerator, thereby effectively enhancing the reliability and stability of the infrared component. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A cross-sectional view of an expander air intake structure for a Stirling refrigerator provided in an embodiment of the present application;

[0022] Figure 2 A schematic diagram of a first slit-type airway of a push piston plugging portion provided in an embodiment of the present application;

[0023] Figure 3 A schematic diagram of an inclined circular hole airway of a push piston plugging head provided in an embodiment of the present application;

[0024] Figure 4 A schematic diagram of a second slit-type air duct at the cold end of a heat regenerator provided in an embodiment of the present application.

[0025] Reference numerals:

[0026] Pneumatic chamber 1; second air channel 101; pneumatic chamber end cover 102; push piston 2; rod 201; plugging part 202; inclined circular hole air channel 203; first slit air channel 204; conical recessed surface 205; push piston cylinder sleeve 3; piston cavity 301; first air channel 302; elastic member 4; connecting pipe 5; regenerator 6; second slit air channel 601; expansion cavity 7; cold head 8. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose, the technical solutions in the embodiments of the present application are clearly described. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present application.

[0028] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0029] The description of the method flow in the specification of the present application and the steps of the flowchart in the drawings of the present specification do not have to be strictly executed according to the step numbers, and the method steps can be executed in a different order. Moreover, some steps can be omitted, multiple steps can be combined into one step, and / or one step can be decomposed into multiple steps.

[0030] The expander air intake structure for a Stirling refrigerator provided in the embodiment of the present application is described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0031] First, the application scenario of the expander air intake structure for a Stirling refrigerator in an embodiment of the present application is described in detail.

[0032] In the related technologies known to the inventor, the cold end structure of the Stirling refrigerator regenerator 6 and the push piston 2 are generally round hole type and are made of PEEK material or metal material. The pressure fluctuations generated by the compressor drive the working medium (working medium) to move back and forth inside the regenerator 6. During this process, the working medium will contact the filler in the regenerator 6, thereby realizing heat transfer from one end to the other end, achieving a cooling effect.

[0033] Based on the technical solution in the related art that the cold end of the heat exchanger and the push piston 2 are circular hole-type air intake structures, a certain flow resistance will be generated for the working fluid entering and exiting, and eddy currents will be formed at the hot and cold ends of the working fluid. When the working fluid passes through the regenerator 6, especially when interacting with the internal filler, resistance will be generated, which is called flow resistance loss. The irregular flow (eddy current) formed when the working fluid enters and exits the regenerator 6 due to structural design reasons will also lead to energy loss, namely eddy current loss. In infrared applications, the above phenomenon will cause the Stirling refrigerator to consume a large amount of power and take a long time to cool down, which reduces the refrigeration efficiency, and further leads to high power consumption of the entire infrared generating component, and even the problem of being unable to image.

[0034] In order to reduce the above two forms of energy loss and improve the refrigeration efficiency, the present application proposes a method of optimizing the structure of the regenerator 6 cold head 8 and the push piston 2 of the Stirling refrigerator, changing the circular hole type flow channel in the related technology into a slit type structure, thereby avoiding large flow resistance loss and eddy current when the working fluid enters and exits the regenerator 6, improving the refrigeration performance and stability of the Stirling refrigerator, and thereby reducing the power consumption of the entire infrared component and improving the reliability of the infrared component.

[0035] See also Figure 1-4 , the embodiment of the present application provides an expander intake structure for a Stirling refrigerator, such as Figure 1-4 As shown, the expander air intake structure of the embodiment of the present application includes:

[0036] A pneumatic chamber 1 for accommodating a piston assembly and a regenerator 6;

[0037] The piston assembly comprises a push piston 2 and a push piston cylinder sleeve 3;

[0038] The push piston 2 includes a rod portion 201 and a plug portion 202; the push piston cylinder sleeve 3 includes a piston chamber 301 for accommodating the push piston 2; the push piston cylinder sleeve 3 is sleeved on the rod portion 201 of the push piston 2 and the plug portion 202 of the push piston 2 is placed in the piston chamber 301 to form a piston structure; one end of the push piston 2 away from the plug portion 202 extends to the outside of the piston chamber 301 and is fixedly connected with an elastic member 4 for providing a reset force for the push piston 2; the piston chamber 301 is provided with a first air channel 302 for communicating with the pneumatic chamber 1; the pneumatic chamber 1 is provided with a second air channel 101 for connecting to a connecting pipe 5, and the connecting pipe 5 is used to connect to a compressor to provide a driving force for the push piston 2;

[0039] The plugging portion 202 of the push piston 2 includes a plurality of inclined circular hole air channels 203 evenly distributed around the central axis of the push piston 2, and the plurality of inclined circular hole air channels 203 extend along the end surface of the plugging portion 202 close to the rod portion 201 into the plugging portion 202 and intersect at the set position of the central axis of the push piston 2; one end of the plugging portion 202 away from the rod portion 201 is provided with a plurality of first slit-type air channels 204 connected to the inclined circular hole air channels 203, and the plurality of first slit-type air channels 204 are evenly distributed around the central axis of the push piston 2 and intersect at the central axis of the push piston 2; the end surface of the plugging portion 202 away from the rod portion 201 is provided with a conical recessed surface 205 at the intersection of the plurality of first slit-type air channels 204.

[0040] The push piston 2 is fixedly connected to the hot end of the regenerator 6; the cold end of the regenerator 6 is provided with a plurality of second slit air ducts 601, which are evenly distributed around the central axis of the regenerator 6 and converge at the central axis of the regenerator 6.

[0041] The working principle of this application is:

[0042] After being compressed in the compressor, the working gas enters the expander through the connecting pipe 5. The gas enters the piston chamber 301 through the second gas channel 101, the pneumatic chamber 1, and the first gas channel 302 in sequence, and then enters the regenerator 6 through the inclined circular hole gas channel 203 and the first slit gas channel 204, releasing heat to the regenerator 6 filler. At this time, the working gas temperature and pressure both drop, and then enter the expansion chamber 7 through the second slit gas channel 601 for expansion and refrigeration, and the cold energy is extracted by the cold head 8. The expanded gas flows back to the inside of the regenerator 6 through the second slit gas channel 601 to absorb the heat of the filler. At this time, the temperature and pressure of the working gas both rise, and finally flow back to the compressor to continue to be compressed, completing a cycle.

[0043] In the above process, the present application optimizes the cold end flow channel structure of the regenerator 6 and the hot end push piston 2 plug flow channel structure, and changes the traditional round hole structure into the following Figure 2 and Figure 4 The slit-type structure shown allows the internal working fluid to enter and exit the regenerator 6 in a laminar flow manner, avoiding the occurrence of eddy currents at the inlet and outlet; the structure of the present application can effectively enhance the laminar flow state of the working fluid at the inlet and outlet of the piston 2 plug at the cold and hot ends of the regenerator 6, improve the refrigeration efficiency of the Stirling refrigerator, and ultimately effectively enhance the reliability and stability of the infrared component.

[0044] In some possible implementations, the slit width, length and number of the first slit air channel 204 and the second slit air channel 601 are determined according to the required cooling capacity and efficiency of the refrigerator. For different refrigerators, structures with different widths and slit numbers can be used to maximize the performance of the Stirling refrigerator.

[0045] In some possible implementations, the inclined circular hole air channels 203 may be configured in combinations of 4, 6, etc.

[0046] In some possible implementations, the hot end of the regenerator 6 is connected to the plug 202 of the push piston 2 by adhesive to fix the relative position of the regenerator 6 and the push piston 2. In some possible implementations, the elastic member 4 can be configured as a spring, the push piston cylinder sleeve 3 is connected to the spring by laser welding, and the spring is connected to the rod 201 of the push piston 2 by threads and thread glue. The connection between the above various components ensures the effective operation of the expander.

[0047] In some possible implementations, the pneumatic chamber 1 includes an openable and closable end cover of the pneumatic chamber 1 .

[0048] To sum up, the present application has a simple structure and is easy to process; only the structure of the regenerator and the hot-end push piston plug is changed, which will not affect the original assembly relationship and sequence of the refrigerator, and can effectively enhance the laminar flow state of the working fluid at the inlet and outlet of the cold-end and hot-end push piston plugs of the regenerator, reduce flow resistance loss and eddy current loss, and improve the refrigeration efficiency of the Stirling refrigerator, thereby effectively enhancing the reliability and stability of the infrared component.

[0049] It should be noted that, in this article, the term "comprises", "includes" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the method and device in the embodiment of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0050] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. An expander air intake structure for a Stirling refrigerator, characterized in that: include: a pneumatic chamber for accommodating the piston assembly and the regenerator; The piston assembly comprises a push piston and a push piston cylinder sleeve; The push piston comprises a rod portion and a plug portion; The plugging portion of the push piston comprises a plurality of inclined circular hole air passages evenly distributed around the central axis of the push piston, and the plurality of inclined circular hole air passages extend along the end surface of the plugging portion close to the rod portion into the plugging portion and intersect at the set position of the central axis of the push piston; the end of the plugging portion away from the rod portion is provided with a plurality of first slit-type air passages connected with the inclined circular hole air passages, and the plurality of first slit-type air passages are evenly distributed around the central axis of the push piston and intersect at the central axis of the push piston; the end surface of the plugging portion away from the rod portion is provided with a conical concave surface at the intersection of the plurality of first slit-type air passages; The push piston is fixedly connected to the hot end of the heat regenerator; a plurality of second slit air ducts are arranged at the cold end of the heat regenerator, and the plurality of second slit air ducts are evenly distributed around the central axis of the heat regenerator and intersect at the central axis of the heat regenerator.

2. The expander air intake structure for Stirling refrigerator according to claim 1, characterized in that: The push piston cylinder sleeve includes a piston chamber for accommodating the push piston; the push piston cylinder sleeve is sleeved on the rod portion of the push piston and the plugging portion of the push piston is placed in the piston chamber to form a piston structure; one end of the push piston away from the plugging portion extends to the outside of the piston chamber and is fixedly connected with an elastic member to provide a reset force for the push piston; the piston chamber is provided with a first air channel for communicating with the pneumatic chamber; the pneumatic chamber is provided with a second air channel for connecting a connecting pipe, and the connecting pipe is used to be connected to a compressor to provide a driving force for the push piston.

3. The expander air intake structure for a Stirling refrigerator according to claim 1 or 2, characterized in that: The slit width, length and number of the first slit air duct and the second slit air duct are determined according to the required cooling capacity and efficiency of the refrigerator.

4. The expander air intake structure for a Stirling refrigerator according to claim 1, characterized in that: The number of the inclined circular hole airways is 4.

5. The expander air intake structure for Stirling refrigerator according to claim 1, characterized in that: The hot end of the regenerator is connected to the plugging portion of the push piston by adhesive.

6. The expander air intake structure for Stirling refrigerator according to claim 2, characterized in that: The elastic member is configured as a spring, the push piston cylinder sleeve and the spring are connected by laser welding, and the spring and the rod portion of the push piston are connected by threads and thread glue.

7. The expander air intake structure for a Stirling refrigerator according to claim 1, characterized in that: The pneumatic chamber comprises an openable and closable pneumatic chamber end cover.

8. A Stirling refrigerator, characterized in that: It comprises an expander air intake structure for a Stirling refrigerator as described in any one of claims 1 to 7.

9. An infrared device, characterized in that: Comprising the Stirling refrigerator as claimed in claim 8.

Images