A linear low-temperature mechanical refrigerator

Abstract

The present invention relates to a linear low-temperature mechanical refrigerator. By controlling a single-side motor of a single-back-pressure chamber dual-gas-path opposed linear compressor, the independent operation of a single-side cold finger and the simultaneous operation of both-side cold fingers can be realized. By separating the compression chamber and the air outlet pipeline and symmetrically arranging the pistons, the linear low-temperature mechanical refrigerator can be made compact in structure and the vibration of the compressor can be reduced without adding a passive vibration absorber. When only one side of the motor is working, the cold finger and the compression chamber on the other side become back-pressure chambers, further increasing the volume of the back-pressure chamber and avoiding the displacement of the equilibrium position of the piston due to the action of gas force.

Description

Technical Field

[0001] The present invention belongs to the technical field of refrigerators, and in particular relates to a linear low-temperature mechanical refrigerator. Background Art

[0002] Infrared detectors are core components of infrared detection, infrared night vision, and infrared guidance devices. Cryogenic mechanical refrigerators provide a low-temperature environment for detector chips, reducing noise and improving image quality, making them a key component of infrared detectors.

[0003] Stirling refrigerators and pulse tube refrigerators are widely used in military and civilian applications, including space and ground-based infrared detection, infrared night vision, and infrared guidance. Cryogenic mechanical refrigerators are key components of infrared detectors.

[0004] Infrared detectors for aviation, aerospace and weapons require refrigerators that are small in size, light in weight and have high performance, which requires refrigerators to have a high power-to-weight ratio (ratio of input power to weight).

[0005] Infrared detectors capable of simultaneously detecting multiple wavelengths, including shortwave, mediumwave, and longwave, are becoming a hot topic in research and application, as they can meet the needs of detecting signals in complex environments. Multi-head cryogenic refrigerators are a key technology for realizing multi-band infrared detectors.

[0006] When a conventional opposed linear compressor drives a dual cold head, a gas distributor is required. This results in uneven gas distribution and mutual influence between the two cold fingers, which reduces the stability and reliability of the detector system. In addition, the gap seal causes pressure fluctuations in the back pressure chamber, thereby preventing the piston from shifting its equilibrium position due to gas force.

[0007] When conventional dual cold fingers use a single motor to drive dual pistons, it will cause large vibration of the compressor. Due to the mutual influence of the loads of the two pistons, the working stability of the refrigerator is poor. It is usually required that the chip specifications and cooling capacity of the dual cold fingers need to be consistent, and they can only be started and stopped at the same time. Each cold finger cannot work independently. Summary of the Invention

[0008] The present invention aims to provide a linear low-temperature mechanical refrigerator with a simple structure, easy processing, low cost, good refrigeration effect and stable operation, especially by setting a single back-pressure chamber dual-gas-path opposed linear compressor, so that the vibration of the compressor is small, the piston does not deviate or deviates slightly in the equilibrium position, and has broad application value and usage prospects.

[0009] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0010] A linear low-temperature mechanical refrigerator includes a first linear compressor and a second linear compressor placed in the same housing. The first linear compressor and the second linear compressor are symmetrically arranged, wherein the air outlet end of the first linear compressor is connected to a first group of cold fingers through a first connection, and the air outlet end of the second linear compressor is connected to a second group of cold fingers through a second connection.

[0011] As a preferred embodiment of the linear cryogenic mechanical refrigerator of the present invention, at least some of the cold fingers in the first group of cold fingers or the second group of cold fingers are Stirling-type cold fingers or pulse-tube-type cold fingers.

[0012] As a preferred solution of the linear low-temperature mechanical refrigerator of the present invention, the cylinder bases of the first linear compressor and the second linear compressor are integrally arranged.

[0013] As a preferred solution of the linear low-temperature mechanical refrigerator of the present invention, the first linear compressor and the second linear compressor are arranged opposite to each other and their compression chambers are separated.

[0014] As a preferred solution of the linear low-temperature mechanical refrigerator of the present invention, the first linear compressor and the second linear compressor are arranged back to back.

[0015] As a preferred solution of the linear low-temperature mechanical refrigerator of the present invention, the back pressure chambers of the first linear compressor and the second linear compressor are connected.

[0016] As a preferred embodiment of the linear low-temperature mechanical refrigerator described in the present invention, the back pressure chambers of the first linear compressor and the second linear compressor are both connected to the air inlet, and the air inlet is opened on the cylinder seat. An inflation valve pin threadedly connected to the cylinder seat is provided at the air inlet, and an air valve sealing ring is provided between the inflation valve pin and the air inlet.

[0017] As a preferred embodiment of the linear low-temperature mechanical refrigerator described in the present invention, the first linear compressor or the second linear compressor includes a linear motor, a cylinder seat, a piston and a support component. The piston is supported by the support component and slides in the cylinder seat. The piston is connected to the mover frame of the linear motor.

[0018] As a preferred solution of the linear low-temperature mechanical refrigerator described in the present invention, the linear motor is a moving coil type, a moving magnet type or a moving iron type linear motor.

[0019] As a preferred solution of the linear low-temperature mechanical refrigerator described in the present invention, the support component is supported by a single-side leaf spring support, a gas bearing support or a magnetic spring support.

[0020] To solve the above technical problems, according to another aspect of the present invention, the present invention provides the following technical solution for the refrigeration process of a linear low-temperature mechanical refrigerator:

[0021] Sinusoidal alternating current is passed through the symmetrically arranged first and second linear compressors, and the working fluid gas is compressed in the two compression systems of the compressors. The compression chamber and the back pressure chamber are isolated by the gap sealing effect between the piston and the cylinder. The pressurized working fluid gas in the two compression chambers enters the first and second groups of cold fingers respectively through connecting pipes. After expansion and heat absorption, the first and second chips located at the cold heads of the cold fingers are cooled. The expanded gas in the cold fingers is sucked into the connecting pipes and then enters the compressor, completing the entire cycle.

[0022] The preferred solution is to loosen the inflation valve pin and separate the air valve sealing ring from the cylinder seat. The working fluid enters the back pressure chamber through the inflation valve pin thread and the small hole of the cylinder seat, and then enters the cold fingers on both sides through the gap between the cylinder and the piston. After reaching the working pressure, tighten the inflation valve pin, and the pre-compression air valve sealing ring is sealed by metal creep to complete the inflation. The motors on both sides can be independently powered by AC power to independently realize the compression and expansion of the working fluid gas in the two sets of cylinders, providing periodic pressure waves for the cold fingers.

[0023] The beneficial effects of the present invention are as follows:

[0024] The present invention provides a linear low-temperature mechanical refrigerator and a refrigeration process thereof, which have the following advantages:

[0025] (1) Conventional dual-cold-finger low-temperature mechanical refrigerators adopt a Y-type structure, which divides the single gas path of a conventional linear compressor into two paths, driving two sets of cold fingers respectively. When the conventional linear compressor drives the dual cold fingers, the dual cold fingers start and stop at the same time, and the load requirements are consistent. However, the present invention uses a separate motor to control a single cold finger, which can realize the independent operation of a single-side cold finger and the simultaneous operation of both sides of the cold fingers. By independently distributing the compression chamber and the connecting pipe, the chips on both sides can operate independently without affecting each other, and the structure is more compact.

[0026] (2) Conventional multi-band infrared detectors use a single refrigerator cold head to cool a single multi-band infrared chip, while the present invention can set up several refrigerator cold heads as needed, and can set up a high power-to-weight ratio linear low-temperature mechanical refrigerator structure with 4 sets, 6 sets or more cold finger structures.

[0027] (3) When a conventional opposed linear compressor drives a dual cold head, a gas distributor is required. There are problems of uneven distribution of the gas paths of the two cold fingers and mutual influence, which reduces the stability and reliability of the detector system. However, the present invention uses a single back pressure chamber dual gas path opposed linear compressor, which not only has a good vibration reduction effect, but also can achieve uniform gas path distribution without the need for a gas distributor.

[0028] (4) Compared with conventional opposed linear compressors, the pistons on both sides of the opposed compressor proposed by the present invention share the same back pressure chamber and air inlet, but the compression chamber and the air outlet pipe are separated, and the structure is simpler and more compact. In addition, the symmetrical arrangement of the pistons can reduce the vibration of the compressor without adding a passive shock absorber to reduce vibration, thereby solving the problem of large vibration of a single motor and a single piston. In addition, when only one side of the motor is working, the cold finger and the compression chamber on the other side become back pressure chambers. At this time, the volume of the back pressure chamber is much larger than that of the compression chamber, and the back pressure chamber pressure fluctuations due to the gap seal will not be caused, thereby avoiding the piston from shifting the equilibrium position due to the action of gas force.

[0029] (5) The linear low-temperature mechanical refrigerator of the present invention has flexible use occasions and rich application scenarios. The linear motor parts, pistons, and air paths of the compression chamber and expansion chamber corresponding to the double-sided cold fingers of the present invention are completely independent. Through motor control, both the double-sided chips can work simultaneously, and the single-sided chip can work. When the single-sided chip operation mode is adopted, the compression chamber and air path corresponding to the other side chip become the back pressure chamber of the operation side. At this time, the volume of the back pressure chamber is much larger than the volume of the compression chamber, which can avoid the displacement of the piston equilibrium position caused by the pressure difference between the compression chamber and the back pressure chamber. When the double-sided chips are running at the same time, there is no need to ensure that the chip specifications are completely consistent. The stable operation of the multi-band detector can be achieved at the same time. The double-sided motors can also independently adjust the input power consumption according to the chip requirements. That is, the double-sided cold finger structure of the present invention can realize the functions of multiple refrigerators. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, 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 the structures shown in these drawings without paying any creative work.

[0031] Figure 1 Schematic diagram of a dual-cold-head linear low-temperature mechanical refrigerator according to the present invention;

[0032] Figure 2 A schematic diagram of an opposed linear compressor according to the present invention;

[0033] Figure 3 This is a diagram of the cylinder seat and inflation structure involved in the present invention;

[0034] Figure 4 This is a schematic diagram of a four-cold-head linear low-temperature mechanical refrigerator according to the present invention.

[0035] Among them, 1-linear compressor, 21-first chip, 22-second chip, 31-first cold finger, 32-second cold finger, 33-third cold finger, 34-fourth cold finger, 41-first connection, 42-second connection, 51-first end cover, 52-second end cover, 61-first piston, 62-second piston, 7-inner magnetic yoke, 8-magnet, 9-coil, 10-outer magnetic yoke, 11-inflating valve pin, 12-valve sealing ring, 13-cylinder seat, 14-stator frame, 15-motor frame, 16-leaf spring, 17-compression chamber, 18-back pressure chamber, 71-first linear compressor, 72-second linear compressor.

[0036] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0037] The following will be a clear and complete description of the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0038] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0039] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0040] The technical solution of the present invention is further described below with reference to specific embodiments.

[0041] Example 1

[0042] This embodiment Figure 1-3As shown, a linear low-temperature mechanical refrigerator includes a single-backpressure chamber, dual-gas-path opposed linear compressor 1, namely, a first linear compressor 71 and a second linear compressor 72 housed in the same housing, wherein the first linear compressor 71 and the second linear compressor 72 are symmetrically arranged. The refrigerator also includes a first group of cold fingers, a first connection 41, a second group of cold fingers, and a second connection 42. The outlet of the first linear compressor 71 is connected to the first group of cold fingers via the first connection 41, and the outlet of the second linear compressor 72 is connected to the second group of cold fingers via the second connection 42. The first and second groups of cold fingers each include at least one cold finger, and at least some of the cold fingers in the first or second group of cold fingers are Stirling-type or pulse-tube-type cold fingers. The cold fingers are driven pneumatically or electrically. In this embodiment, the first and second groups of cold fingers each include one cold finger, namely, a first cold finger 31 and a second cold finger 32, respectively. In this embodiment, a first linear compressor 71 and a second linear compressor 72 are arranged opposite each other, and the compressors on both sides are symmetrically arranged with the same structure. Each linear motor is independently provided. The linear motor includes a coil 9, a magnet 8, an inner magnetic yoke 7, an outer magnetic yoke 10, a stator frame 14, and a mover frame 15. Both sides are also provided with a support and compression system, which includes a compression chamber 17, a backpressure chamber 18, a cylinder base 13, a piston 6, and a leaf spring 16. The piston 6 is supported and slidably positioned in the cylinder base 13 by the leaf spring 16. The piston 6 is connected to the mover frame 15 of the linear motor. During operation, the linear motor drives the piston 6 to reciprocate via the mover frame 15. The pistons 6 on each side are respectively a first piston 61 and a second piston 62, and the linear motors on both sides drive the first piston 61 and the second piston 62, respectively. The cylinder base 13 of the first and second linear compressors 71 and 72 is integrated, which can reduce vibration generated during compressor operation. The compression chambers 17 of the first and second linear compressors 71 and 72 are separated. A baffle plate is installed in the middle of the integral cylinder block 13 to separate the compression chambers on both sides, thereby splitting the single air path into two paths, each driving two sets of cold fingers. The single-backpressure chamber, dual-air-path opposed linear compressor includes opposing first and second end caps 51 and 52, which are respectively placed over the openings on either side of the housing to achieve a seal.

[0043] In other embodiments, the first linear compressor 71 and the second linear compressor 72 can also be arranged back to back. In this case, the compression chambers of the two are separated, and there is no need to set a baffle to separate the compression chambers of the two. The other structures are similar to the above-mentioned opposing scheme and will not be repeated here.

[0044] The linear motor described in this embodiment is a moving magnet type, and in other embodiments it may also be a moving coil type or a moving iron type linear motor.

[0045] In this embodiment, the supporting member is supported by a single-side leaf spring. In other embodiments, it may be supported by a gas bearing or a magnetic spring.

[0046] The linear motor drives the corresponding piston movement, thereby compressing the working fluid gas into the corresponding cold finger. Since the linear motor is independently controlled, the cold finger on one side can operate independently and the cold fingers on both sides can operate simultaneously. By independently distributing the compression chamber and the connecting pipe, the chips on both sides can operate independently without affecting each other, and the structure is more compact.

[0047] Example 2

[0048] The embodiment is improved on the basis of Example 1, in which the back pressure chambers 18 of the first linear compressor 71 and the second linear compressor 72 are connected, and further includes an air inlet connected to the back pressure chambers 18 of both the first linear compressor 71 and the second linear compressor 72. In this embodiment, the back pressure chambers 18 of the two are connected by opening a connecting hole on the cylinder seat 13. The air inlet is opened on the cylinder seat 13 and connected to the connecting hole. An inflation valve pin 11 threadedly connected to the cylinder seat 13 is provided at the air inlet. The air inlet is closed and opened by tightening or loosening the threads between the inflation valve pin 11 and the cylinder seat 13. An air valve sealing ring 12 is also provided between the inflation valve pin 11 and the air inlet to achieve a better sealing effect. The first piston 61 and the second piston 62 of the opposed compressor share the same back-pressure chamber 18 and the air inlet, and the compression chamber and the air outlet pipe are separated. The advantage of sharing the back-pressure chamber is that when the motor on one side is working, the cold finger and the compression chamber on the other side become back-pressure chambers. Without adding other components, the volume of the back-pressure chamber is increased, and the volume advantage of the back-pressure chamber volume relative to the compression chamber volume is further increased. The back-pressure chamber pressure fluctuation will not be caused by the gap seal, thereby avoiding the piston from shifting the equilibrium position due to the action of gas force.

[0049] Example 3

[0050] A refrigeration process utilizing a linear low-temperature mechanical refrigerator is characterized by comprising: sinusoidal alternating current supplied to linear motors on both sides of a linear compressor, compressing a working fluid gas in the two compression systems of the compressor. The compression chamber is isolated from the back-pressure chamber by the sealing effect of the gap between the piston and the cylinder. The working fluid gas in the two compression chambers enters the first cold finger 31 and the second cold finger 32 respectively through a connecting pipe, expands and absorbs heat, and then cools the first chip 21 and the second chip 22 located at the cold ends of the cold fingers. The expanded gas in the cold fingers is drawn into the connecting pipe and then enters the compressor, completing the entire cycle. By loosening the inflation valve pin, the valve seal ring is separated from the cylinder seat, and the working fluid enters the back-pressure chamber through the inflation valve pin thread and the small hole in the cylinder seat, and then enters the two cold fingers through the gap between the cylinder and the piston. After reaching the working pressure, the inflation valve pin is tightened, and the pre-compression valve seal ring is sealed by metal creep, completing inflation. The two motors can be independently powered by alternating current, and the working fluid gas is compressed and expanded in the two cylinders respectively, providing periodic pressure waves for the cold fingers.

[0051] Example 4

[0052] This embodiment Figure 4 As shown, a linear low-temperature mechanical refrigerator comprises a single-backpressure chamber, dual-gas-circuit opposed linear compressor 1, a first cold finger 31, a third cold finger 33, a first connection 41, a second cold finger 32, a fourth cold finger 34, and a second connection 42. The first connection 41 connects the first and third cold fingers 31, 33, and the second connection 42 connects the second and fourth cold fingers 32, 34. Thus, both the first and second cold finger groups include two cold fingers. In other embodiments, the first and second cold finger groups may include a larger number of cold fingers, as long as the cooling capacity meets the operating requirements. The linear compressors are arranged in opposing configurations, with identical symmetrical structures on both sides. Independent linear motors are provided on each side. The linear motors include a coil 9, a magnet 8, an inner yoke 7, an outer yoke 10, a stator frame 14, and a rotor frame 15. A support and compression system is also provided, comprising a compression chamber 17, a cylinder base 13, a piston 6, and a leaf spring 16 to provide enhanced support for the entire device.

[0053] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A linear low-temperature mechanical refrigerator, characterized in that: The invention comprises a first linear compressor and a second linear compressor placed in the same housing, wherein the first linear compressor and the second linear compressor are symmetrically arranged, wherein the air outlet end of the first linear compressor is connected to the first group of cold fingers via a first connection, and the air outlet end of the second linear compressor is connected to the second group of cold fingers via a second connection; the first linear compressor and the second linear compressor are arranged opposite to each other and the compression chambers thereof are separated, and the back pressure chambers of the first linear compressor and the second linear compressor are connected.

2. The linear cryogenic mechanical refrigerator according to claim 1, characterized in that: At least some of the cold fingers in the first group of cold fingers or the second group of cold fingers are Stirling type cold fingers or pulse tube type cold fingers.

3. The linear cryogenic mechanical refrigerator according to claim 1, characterized in that: The cylinder bases of the first linear compressor and the second linear compressor are integrally arranged.

4. The linear cryogenic mechanical refrigerator according to claim 1, characterized in that: The first linear compressor and the second linear compressor are arranged back to back.

5. The linear cryogenic mechanical refrigerator according to claim 1, characterized in that: It also includes an air inlet connected to the back pressure chambers of the first linear compressor and the second linear compressor. The air inlet is opened on the cylinder seat. An inflation valve pin threadedly connected to the cylinder seat is provided at the air inlet. An air valve sealing ring is provided between the inflation valve pin and the air inlet.

6. The linear cryogenic mechanical refrigerator according to claim 1, characterized in that: The first linear compressor or the second linear compressor includes a linear motor, a cylinder seat, a piston and a support component. The piston is supported by the support component and slidably located in the cylinder seat. The piston is connected to the mover frame of the linear motor.

7. The linear cryogenic mechanical refrigerator according to claim 6, characterized in that: The linear motor is a moving coil type, a moving magnet type or a moving iron type linear motor.

8. The linear cryogenic mechanical refrigerator according to claim 6, characterized in that: The supporting component is supported by a single-side leaf spring, a gas bearing or a magnetic spring.

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