A split-jet throttling refrigeration infrared detector

Abstract

The application provides a split injection throttling refrigeration infrared detector, which comprises a refrigerator assembly and a dewar assembly, the refrigerator assembly is located outside the dewar assembly, the dewar assembly has an injection pipe for injecting cold fluid inside, and the refrigerator assembly is communicated with the injection pipe through a refrigeration stage hose. The application arranges the refrigerator assembly and the dewar assembly separately, connects the refrigerator assembly and the dewar assembly by the refrigeration stage hose, realizes the flexible arrangement of the refrigerator assembly and the dewar assembly by 360 degrees, and meanwhile, the volume of the refrigerator assembly is not limited by the cold finger size of the dewar assembly, so that greater heat exchange efficiency can be realized, and the refrigeration performance of the detector is improved.

Description

Technical Field

[0001] This invention belongs to the field of infrared detector technology, and specifically relates to a split-jet throttling cooled infrared detector. Background Technology

[0002] Infrared detectors are widely used in civilian and military equipment such as infrared thermal imagers, infrared forward-looking and night vision devices, missile guidance, and space applications. Throttling coolers are used in detectors, with the Dewar cold finger serving as part of the cooler's heat exchanger. This restricts the flow direction of the returning fluid after throttling, allowing the returning cold fluid to exchange heat with the heat exchanger wall, thereby cooling the incoming flow and amplifying the throttling effect.

[0003] However, existing Dewar cold fingers and throttling refrigerators are integrated into one structure. As a component of the refrigerator's heat exchanger, the size of the refrigerator is limited by the size of the Dewar cold fingers, and the efficiency of the refrigerator is limited by parameters such as the heat exchange area. Or, in order to ensure cooling performance, the Dewar volume is too large, which does not meet the usage requirements, especially for the guide head. Summary of the Invention

[0004] The purpose of this invention is to provide a split-jet throttling cooled infrared detector, which can at least solve some of the defects existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A split-ejection throttling cooled infrared detector includes a cooler assembly and a Dewar assembly. The cooler assembly is located outside the Dewar assembly, and the Dewar assembly has an injection pipe inside for ejecting cold fluid. The cooler assembly is connected to the injection pipe via a cooling stage hose.

[0007] Furthermore, the refrigeration assembly includes a refrigeration housing and a mandrel disposed inside the refrigeration housing. A precooling stage tube is provided between the refrigeration housing and the mandrel. The refrigeration stage tube includes a first tube segment, a second tube segment, and a third tube segment connected in sequence. The first tube segment and the second tube segment are located in the refrigeration region of the precooling stage tube. The air inlet end of the precooling stage tube and the end of the first tube segment are both connected to a high-pressure fluid source. The end of the third tube segment extends out of the refrigeration housing and is connected to the injection pipe.

[0008] Furthermore, the end of the refrigerator housing is connected to an inlet flange and an inlet pipe. The inlet flange is provided with a high-pressure fluid channel. One end of the inlet pipe is connected to the high-pressure fluid channel, and the other end of the inlet pipe is provided with an inlet connector for connecting an external high-pressure fluid source. The inlet end of the precooling stage pipe and the first hose section are both connected to the high-pressure fluid channel.

[0009] Further, the pre-cooling stage pipe is wound on the mandrel, the top of the mandrel is provided with a pre-cooling stage throttling element, the gas outlet end of the pre-cooling stage pipe is connected with the pre-cooling stage throttling element, the first hose section is wound on the pre-cooling stage pipe, and the second hose section is coiled outside the end of the mandrel and opposite to the pre-cooling stage throttling element.

[0010] Further, the first hose section, the second hose section and the third hose section are integrated.

[0011] Further, the Dewar assembly comprises a Dewar shell, a cold finger, a cold disc and a cold shield arranged in sequence along an axis in the Dewar shell, the injection pipe is located in the cold finger, the gas outlet end of the injection pipe is arranged opposite to the cold disc, and the gas outlet end of the injection pipe is connected with a refrigeration stage throttling element.

[0012] Further, the Dewar assembly further comprises a fixing clasp ring and a connecting joint, the fixing clasp ring is located at the bottom of the cold finger, the connecting joint penetrates through the fixing clasp ring, and the two ends of the connecting joint are connected with the refrigeration stage hose and the injection pipe respectively.

[0013] Further, the fixing clasp ring is a petal-shaped support ring.

[0014] Further, the cold finger comprises a cylindrical section and a conical section, the small-diameter end of the conical section is connected with the cylindrical section, the injection pipe penetrates through the cylindrical section, the gas outlet end of the injection pipe extends into the conical section, and the cold disc is installed at the large-diameter end of the conical section.

[0015] Further, the refrigeration stage hose is an annealed metal hose, and the injection pipe is a non-annealed metal hard pipe.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] (1) The present application separately arranges the refrigerator assembly and the Dewar assembly, connects the refrigerator assembly and the Dewar assembly by the refrigeration stage hose, realizes the relative 360-degree flexible arrangement of the refrigerator assembly and the Dewar assembly, and meanwhile, the volume of the refrigerator assembly is not limited by the size of the cold finger of the Dewar assembly, so that greater heat exchange efficiency can be realized, and the improvement of the refrigeration performance of the probe is facilitated.

[0018] (2) The cold finger of the Dewar assembly is designed in the form of a cylindrical section and a cylindrical section combination in the present application, so that the cold loss of the cold disc via the cold finger can be effectively reduced, and meanwhile, the flow of the fluid after the throttling of the refrigeration stage can be optimized, the flow dead zone in the expansion chamber formed by the conical section and the cold disc is small, the cold disc surface can be basically covered, and the heat exchange is enhanced.

[0019] The present application will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structure diagram of the split jet throttling refrigeration infrared detector of the present application;

[0021] Figure 2 is a structure diagram of the refrigerator assembly in the present application;

[0022] Figure 3 is a structure diagram of the dewar assembly in the present application;

[0023] Figure 4 is a structure diagram of the fixing clasp in the present application;

[0024] Figure 5 is Figure 4 is a cross-sectional view of A-A in the present application;

[0025] Figure 6 is a working principle diagram of the split jet throttling refrigeration infrared detector of the present application.

[0026] Mark explanation: 1, refrigerator assembly; 2, refrigeration stage hose; 3, dewar assembly; 4, refrigerator shell; 5, mandrel; 6, pre-cooling stage pipe; 7, air inlet flange; 8, high-pressure fluid passage; 9, air inlet pipe; 10, air inlet joint; 11, pre-cooling stage throttling element; 12, dewar shell; 13, pressing block; 14, fixing clasp; 15, connecting joint; 16, jet pipe; 17, cylindrical section; 18, conical section; 19, refrigeration stage throttling element; 20, cold plate; 21, chip; 22, cold screen; 23, window piece; 24, lead ring; 25, exhaust pipe. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0029] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or abutment connection or integral connection; for those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0030] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features; in the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0031] As Figure 1 , Figure 2 and Figure 3 The present embodiment provides a split injection throttling refrigeration infrared detector, which comprises a refrigerator assembly 1 and a dewar assembly 3, the refrigerator assembly 1 is located outside the dewar assembly 3, the dewar assembly 3 has an injection pipe 16 for injecting cold fluid inside, and the refrigerator assembly 1 is communicated with the injection pipe 16 through a refrigeration stage hose 2. In the present embodiment, the refrigerator assembly 1 and the dewar assembly 3 are arranged separately, and the refrigerator assembly 1 and the dewar assembly 3 are connected by the refrigeration stage hose 2, the cold fluid generated by the refrigerator assembly 1 is transported to the dewar assembly 3 through the refrigeration stage hose 2, and the chip 21 mounted on the dewar assembly 3 is cooled through the injection pipe 16 to reach the working temperature of the detector; the structure design of the refrigerator assembly 1 and the dewar assembly 3 in the present embodiment can realize flexible arrangement of the relative position of the refrigerator assembly 1 and the dewar assembly 3, and the volume of the refrigerator assembly 1 is not limited by the size of the cold finger of the dewar assembly 3, which can realize greater heat exchange efficiency and is conducive to the improvement of the refrigeration performance of the detector.

[0032] In the present embodiment, the refrigeration stage hose 2 adopts an annealed metal hose, which can transport cold energy and connect the refrigerator assembly 1 and the dewar assembly 3, and realize 360° flexible arrangement of the relative position of the dewar assembly 3 and the refrigerator assembly 1.

[0033] As a specific embodiment, as Figure 2As shown, the refrigerator assembly 1 comprises a refrigerator shell 4 and a mandrel 5 arranged inside the refrigerator shell 4, and a pre-cooling stage pipe 2 is arranged between the refrigerator shell 4 and the mandrel 5. The pre-cooling stage pipe 4 comprises a first pipe section, a second pipe section and a third pipe section connected in sequence. The first pipe section and the second pipe section are located in a refrigeration area of the pre-cooling stage pipe 2. An air inlet end of the pre-cooling stage pipe 2 and an end of the first pipe section are connected to a high-pressure fluid source. An end of the third pipe section penetrates through the refrigerator shell 4 and is connected to the jet pipe 16. The third pipe section of the pre-cooling stage pipe 2 is sealed by tin soldering after penetrating through the refrigerator shell 4. Preferably, the first pipe section, the second pipe section and the third pipe section of the pre-cooling stage pipe 4 are of an integrated structure, so as to ensure the sealing property of the pre-cooling stage pipe 4. In the embodiment, the pre-cooling stage pipe 6 and the pre-cooling stage pipe 2 are connected to the same gas source. High-pressure normal-temperature gas is divided into two paths and simultaneously enters the pre-cooling stage pipe 6 and the pre-cooling stage pipe 2. The high-pressure gas entering the pre-cooling stage pipe 6 is cooled to generate cold gas. The cold gas is returned and continuously exchanges heat with the high-pressure normal-temperature gas in the pre-cooling stage pipe 6 and the first pipe section and the second pipe section of the pre-cooling stage pipe 2, so as to pre-cool the gas in the pre-cooling stage pipe 6 and the pre-cooling stage pipe 2. At the same time, the high-pressure gas entering the pre-cooling stage pipe 2 is cooled by the cold gas returned from the pre-cooling stage pipe 6, and is then transported by the third pipe section of the pre-cooling stage pipe 2 to the external Dewar assembly 3 to be cooled, and is then jetted by the jet pipe 16 to cool the chip 21 on the Dewar assembly 3.

[0034] Specifically, the end of the refrigerator shell 4 is connected with an air inlet flange 7 and an air inlet pipe 9, the air inlet flange 7 is provided with a high-pressure fluid passage 8, one end of the air inlet pipe 9 communicates with the high-pressure fluid passage 8, the other end of the air inlet pipe 9 is provided with an air inlet joint 10 for connecting with a high-pressure fluid source, the air inlet end of the pre-cooling stage pipe 6 and the first hose section of the refrigeration stage hose 2 communicate with the high-pressure fluid passage 8; meanwhile, the pre-cooling stage pipe 6 is wound on the mandrel 5, the top of the mandrel 5 is provided with a pre-cooling stage throttling element 11, the air outlet end of the pre-cooling stage pipe 6 is connected with the pre-cooling stage throttling element 11, the first hose section of the refrigeration stage hose 2 is wound on the pre-cooling stage pipe 6, and the second hose section is wound outside the end of the mandrel 5 and directly opposite the pre-cooling stage throttling element 11. The refrigerator shell 4 and the mandrel 5 form a backflow space of the cold gas generated by the pre-cooling stage pipe 6 (i.e. the refrigeration area of the pre-cooling stage pipe 6), the pre-cooling stage pipe 6 and the first hose section and the second hose section of the refrigeration stage hose 2 are arranged in the backflow space of the cold gas, the air outlet end of the pre-cooling stage pipe 6 communicates with the pre-cooling stage throttling element 11 at the top of the mandrel 5, and the pre-cooling stage throttling element 11 communicates with the backflow space of the cold gas; the high-pressure normal-temperature gas enters the pre-cooling stage pipe 6, the pre-cooling stage throttling element 11 generates the cold gas through the throttling refrigeration effect, the cold gas flows back through the backflow space, and the high-pressure normal-temperature gas in the pre-cooling stage pipe 6 and the first hose section and the second hose section of the refrigeration stage hose 2 is cooled, and meanwhile, the second hose section of the refrigeration stage hose 2 is arranged directly opposite the pre-cooling stage throttling element 11, so that the cold gas can better pre-cool the gas in the refrigeration stage hose 2 to be flowed out of the refrigerator assembly.

[0035] Optionally, the mandrel 5 is made of a non-metal material to reduce the thermal mass and axial cold loss of the refrigerator; the pre-cooling stage pipe 6 can be but is not limited to a finned tube structure, and the pre-cooling stage throttling element 11 can be but is not limited to a converging throttling pipe.

[0036] Preferably, a layer of nylon wire is wound on the outer circle of the refrigeration stage hose 2 inside the refrigerator shell 4 (not shown in the figure), the gap between the refrigeration stage hose 2 and the refrigerator shell 4 is filled with the nylon wire to improve the heat exchange effect of the backflow space of the cold gas.

[0037] Optionally, the pre-cooling stage pipe 6 and the refrigeration stage hose 2 can be provided with the same air inlet passage or different air inlet passages to achieve the purpose of using the same kind or different kinds of refrigeration gas, and further achieve better refrigeration performance and different target temperatures.

[0038] As a specific embodiment, as Figure 3As shown, the dewar assembly 3 comprises a dewar shell 12, a cold finger, a cold plate 20 and a cold shield 22 arranged in sequence along an axis in the dewar shell 12, the jet pipe 16 is located in the cold finger, and the gas outlet end of the jet pipe 16 is arranged opposite to the cold plate 20, and the gas outlet end of the jet pipe 16 is connected with a refrigeration stage throttling element 19. In the present embodiment, the pre-cooled gas in the first and second hose sections of the refrigeration stage hose 2 in the refrigerator assembly 1 is delivered to the cold finger through the third hose section of the refrigeration stage hose 2, and is further cooled and refrigerated by the refrigeration stage throttling element 19 in the cold finger to cool the chip 21 mounted on the cold plate 20 to the detector operating temperature.

[0039] Preferably, the cold finger is designed to comprise a cylindrical section 17 and a conical section 18, the small-diameter end of the conical section 18 is connected with the cylindrical section 17, the jet pipe 16 penetrates through the cylindrical section 17, and the gas outlet end of the jet pipe 16 extends into the conical section 18, and the cold plate 20 is mounted at the large-diameter end of the conical section 18. In the present embodiment, the inner diameter of the cylindrical section 17 of the cold finger depends on the outer diameter of the jet pipe 16 and the design value of the backflow gap, and the cold gas delivered by the refrigerator assembly 1 enters the cold finger. Since the conical section 18 of the cold finger is in the shape of a conical funnel, the diameter of the end close to the cold plate 20 is large, so compared with the conventional cylindrical or large-at-top small-at-bottom conical cold finger structure, the cold gas can stay in the cold end (i.e. the conical section 18) of the cold finger for a longer time, and at the same time, the fluid disturbance of the cold gas in the cold end of the cold finger can be increased, the flow dead zone of the cold gas in the expansion chamber formed by the conical section 18 and the cold plate 20 is small, and the surface of the cold plate 20 can be basically covered, so as to fully utilize the cold quantity of the cold gas, improve the utilization efficiency of the cold gas, strengthen the heat exchange between the cold gas and the cold plate 20, and thus the dewar cold head has a faster cooling effect.

[0040] In order to ensure the centering degree of the jet pipe 16 in the cold finger and prevent the pipe position deviation caused by the refrigeration gas injection process, preferably, the jet pipe 16 is a non-annealed metal hard pipe, and the jet pipe 16 is fixedly installed.

[0041] Preferably, the Dewar assembly 3 further includes a retaining ring 14 and a connecting joint 15. The retaining ring 14 is located at the bottom of the cold finger, and the connecting joint 15 passes through the retaining ring 14. The connecting joint 15 and the retaining ring 14 are cured and bonded together. During the curing process, tooling is used to ensure axial alignment. The two ends of the connecting joint 15 are respectively connected to the refrigeration stage hose 2 and the injection pipe 16. Specifically, the bottom of the cold finger is provided with a cold finger flange for connecting to the Dewar housing 12. The retaining ring 14 is located inside the cold finger flange, and a pressure block 13 is designed to press on the retaining ring 14. The pressure block 13 has a hollow structure and is fixedly connected to the cold finger flange. During operation, the gas exiting from the refrigeration stage throttling element 19 at the end of the injection pipe 16 first flows back through the channel between the injection pipe 16 and the cold finger, and then passes through the gap of the retaining ring 14 and the gap in the middle of the pressure block 13 before being discharged into the external environment.

[0042] Optimized, such as Figure 4 and Figure 5 As shown, the fixing ring 14 can be designed as a petal-shaped support ring. The petal-shaped structure design can ensure the backflow flow area of ​​the refrigeration gas generated by the refrigeration stage throttling element 19. After the refrigeration stage throttling, the pressure difference between the back pressure and atmospheric pressure is less than 100 kPa, and the refrigeration temperature reaches the boiling point temperature, avoiding the influence of high back pressure on the refrigeration temperature. Furthermore, the fixing ring 14 can be designed to be made of a low thermal conductivity non-metallic material. The design of the low thermal conductivity non-metallic material can effectively reduce the cold loss of low temperature gas in the injection pipe 16 through the fixing ring 14. The low thermal conductivity non-metallic material can be selected from, but is not limited to, PEEK (polyether ether ketone), polytetrafluoroethylene, etc.

[0043] In a preferred embodiment, the structure of the cold plate 20 of the Dewar assembly 2 is improved by providing a concave-convex structure on the plate surface of the cold plate 20 facing the cold finger. In some embodiments, a stabilizing area is formed on the plate surface of the cold plate 20 facing the cold finger, and a plurality of grooves are provided at intervals in the stabilizing area. The grooves can be countersunk holes, strip grooves, or annular grooves. The cold plate 20 is usually disc-shaped, and the grooves are preferably arranged in a disc shape in the stabilizing area. Of course, the grooves can also be arranged in other shapes according to the actual situation of the cold plate 20. A plurality of ribs protruding towards the cold finger are also provided on the plate surface of the cold plate 20 facing the cold finger. The plurality of ribs are located outside the stabilizing area. The ribs can be convex ribs or strip-shaped convex ridges, and the ribs are arranged to form a multi-ring structure. In this embodiment, by designing ribs on one side of the cold plate 20 where it exchanges heat with the cold gas, it is beneficial to enhance the convective heat exchange between the cold plate 20 and the cold gas inside the cold finger. At the same time, the design of the groove can disrupt the film heat exchange during the heat exchange between the cold gas and the cold plate 20, enhance the heat exchange between the cold gas and the cold plate 20, thereby accelerating the heat transfer rate and reducing the heat transfer time.

[0044] Further, the cold plate 20 is further provided with an annular flange on the side close to the cold finger, which is used for connecting with the cold finger, and the rib column and the groove on the cold plate 20 are located in the interval formed by the annular flange.

[0045] In the preferred embodiment, the cold screen 22 is mainly used for suppressing stray light, and in the embodiment, the cold screen 22 is designed as an integrated structure with the bottom being wider than the top, and the bottom of the cold screen 22 is widened. Specifically, as shown in Figure 3 The cold screen 22 includes a conical cylinder segment and a prismatic cylinder segment, and the prismatic cylinder segment is formed by cutting the bottom of the conical cylinder segment, so that the thermal mass of the cold screen is reduced, and the cold loss on the heat conduction path is reduced. Further, the bottom of the prismatic cylinder segment is designed to have a connecting portion extending radially outward, which is used for connecting with the cold plate, and the connecting portion is designed to have a set of oppositely distributed first connecting edges and a set of oppositely distributed second connecting edges, and the radial width of the first connecting edges is smaller than the radial width of the second connecting edges along the prismatic cylinder segment. In this way, the contact area of the first connecting edges with the cold plate is reduced, and the contact area of the connecting portion with the cold plate 20 is reduced by widening the bottom of the cold screen 22, so that the cold loss on the heat conduction path of the cold screen 22 is effectively reduced.

[0046] In the optional embodiment, the dewar shell 12 includes a cold finger shell and a window frame which are detachably connected, the cold finger is arranged in the cold finger shell, the cold plate 20 and the cold screen 22 are arranged in the window frame, the window frame is provided with a window sheet 23 at the top, and the cold finger shell is provided with an exhaust pipe 25 corresponding to the cylindrical segment 17 of the cold finger. The dewar assembly 3 further includes a lead ring 24 which is arranged between the cold finger shell and the window frame. The detector receives the light signal, the chip 21 arranged on the cold plate 20 converts the light signal into an electric signal, and the lead ring 24 leads out the electric signal.

[0047] The working process of the split injection throttling refrigeration infrared detector according to the present application is as follows Figure 6As shown, the high-pressure normal-temperature gas enters the pre-cooling stage pipe 6 and the refrigeration stage hose 2 through the gas inlet joint 10, the gas inlet pipe 9 and the gas inlet flange 7. The high-pressure normal-temperature gas in the pre-cooling stage pipe 6 is throttled at the pre-cooling stage throttling element 11, and the throttled gas is cooled and depressurized, and flows in the gap between the pre-cooling stage pipe 6 and the refrigeration shell 4, and cools a part of the gas in the pre-cooling stage pipe 6 and a part of the gas in the first hose section of the refrigeration stage hose 2, and the cold gas generated at the pre-cooling stage throttling element 11 also exchanges heat with the gas in the second hose section of the refrigeration stage hose 2 at the top of the mandrel 5. The gas in the refrigeration stage hose 2 is cooled by the pre-cooling stage, and the temperature of the gas is low, and the gas is further throttled at the refrigeration stage throttling element 19 to reach a lower temperature. The throttled gas of the refrigeration stage exchanges heat with the cold plate 20 of the Dewar assembly 3, and then cools the chip to reach the working temperature of the detector. The design of the double-stage refrigeration and the back pressure of the throttled refrigeration stage being atmospheric pressure makes the refrigeration assembly achieve the boiling point temperature of the working medium in a very short time.

[0048] The above examples are only illustrative of the present application, and do not constitute a limitation on the protection scope of the present application. Any design identical or similar to the present application falls within the protection scope of the present application.

Claims

1. A split-jet throttling refrigeration infrared detector comprising a refrigerator assembly and a dewar assembly, characterized by: The refrigeration device assembly is located outside the dewar assembly, the dewar assembly has a spray pipe for spraying cold fluid inside, the refrigeration device assembly is communicated with the spray pipe through a refrigeration stage hose; the refrigeration device assembly comprises a refrigeration device shell and a mandrel arranged inside the refrigeration device shell, a pre-cooling stage pipe is arranged between the refrigeration device shell and the mandrel, the refrigeration stage hose comprises a first hose section, a second hose section and a third hose section connected in sequence, the first hose section and the second hose section are located in a refrigeration area of the pre-cooling stage pipe, a pre-cooling stage throttling element is connected to an air outlet end of the pre-cooling stage pipe, cold gas backflow generated through the pre-cooling stage throttling element pre-cools the pre-cooling stage pipe and the first hose section and the second hose section in the refrigeration area of the pre-cooling stage pipe, an air inlet end of the pre-cooling stage pipe and an end of the first hose section are both connected to a high-pressure fluid source, and an end of the third hose section penetrates through the refrigeration device shell and is connected to the spray pipe; the dewar assembly comprises a dewar shell and a cold finger, a cold disc and a cold screen arranged in sequence along an axis inside the dewar shell, the spray pipe is located in the cold finger, and an air outlet end of the spray pipe is arranged opposite to the cold disc, and the air outlet end of the spray pipe is connected to a refrigeration stage throttling element.

2. The split-jet throttling refrigeration infrared detector of claim 1, wherein: An air inlet flange and an air inlet pipe are connected to an end of the refrigeration device shell, the air inlet flange is provided with a high-pressure fluid passage, one end of the air inlet pipe is communicated with the high-pressure fluid passage, and the other end of the air inlet pipe is provided with an air inlet joint for externally connecting a high-pressure fluid source, and the air inlet end of the pre-cooling stage pipe and the first hose section are both communicated with the high-pressure fluid passage.

3. The split-jet throttling refrigeration infrared detector of claim 1, wherein: The pre-cooling stage pipe is wound on the mandrel, the mandrel is provided with a pre-cooling stage throttling element at a top portion, the air outlet end of the pre-cooling stage pipe is connected to the pre-cooling stage throttling element, the first hose section is wound on the pre-cooling stage pipe, and the second hose section is coiled outside an end portion of the mandrel and opposite to the pre-cooling stage throttling element.

4. The split-jet throttling refrigeration infrared detector of claim 1, wherein: The first hose section, the second hose section and the third hose section are of an integrated structure.

5. The split-jet throttling refrigeration infrared detector of claim 1, wherein: The dewar assembly further comprises a fixing clamping ring and a connecting joint, the fixing clamping ring is located at a bottom portion of the cold finger, the connecting joint penetrates through the fixing clamping ring, and two ends of the connecting joint are respectively connected to the refrigeration stage hose and the spray pipe.

6. The split-jet throttling refrigeration infrared detector of claim 5, wherein: The fixing clamping ring is a petal-shaped support ring.

7. The split-jet throttling refrigeration infrared detector of claim 1, wherein: The cold finger comprises a cylindrical section and a conical section, a small-diameter end of the conical section is connected to the cylindrical section, the spray pipe penetrates through the cylindrical section, and an air outlet end of the spray pipe extends into the conical section, and the cold disc is mounted at a large-diameter end of the conical section.

8. The split-jet throttling refrigeration infrared detector of claim 1, wherein: The refrigeration stage hose is an annealed metal hose, and the spray pipe is a non-annealed metal hard pipe.

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