Anti-pollution device for cold optical system of space infrared instrument and application method of anti-pollution device

Abstract

The invention provides an anti-pollution device for a cold optical system of a space infrared instrument and an application method of the anti-pollution device. The normal-temperature optical temperature is about 300K, the cold optical temperature is generally 60-250K, and the temperature gradient of the normal-temperature window assembly and the low-temperature window assembly is large, so that the normal-temperature window assembly and the low-temperature window assembly of the space infrared cold optical system are prevented from being interfered by external temperature by connecting the normal-temperature window assembly and the low-temperature window assembly through the high-heat-resistance non-metal closed cold trap; the high-thermal-resistance non-metal closed cold trap can realize physical isolation between a cold optical part and an external normal-temperature environment and effectively prevent external water vapor and condensable volatile matters from entering, so that pollution to the ends, close to the cold trap, of a normal-temperature window and a cold window is avoided, and volatilization of external organic materials and pollution to a cold optical light inlet caused by the water vapor are prevented; and instrument performance degradation is prevented. Meanwhile, the cold window heating piece fixed to the outer wall, close to the cold window assembly, of the cold optical structure in an adhesive mode effectively prevents the cold window from being subjected to low-temperature adsorption pollution, and a small amount of water vapor in the cold optical structure is heated and removed.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace, and in particular to an anti-pollution device for a cold optical structure of a space infrared instrument and an application method thereof. Background Art

[0002] With the development of high sensitivity and high quantification technology of space infrared remote sensing technology, low temperature cold optical structures are increasingly used in space infrared optical instruments, such as the Fengyun-3 infrared hyperspectral atmospheric sounder, the Fengyun-4 vertical sounder, etc. The use of cold optical design in infrared systems is a necessary means to reduce background noise and improve instrument sensitivity.

[0003] Cold optical structures usually need to be cooled to 60k-250k to work. The surrounding instruments are kept at room temperature. There will be a variety of non-metallic materials, adhesives, conformal coatings, etc. These materials will outgas in a vacuum and the impact will last for a long time. The temperature of the cold optical structure is usually more than 50 degrees Celsius lower than the surrounding environment. Due to the principle of low-temperature adsorption, the open cold optical window will be affected by the surrounding organic pollution and water vapor. When the pollution accumulates, it will cause the performance of some sensitive channels to decay and reduce the performance of the instrument. In order to ensure the long-term stability of the instrument performance, the cold optical structure must be equipped with an anti-pollution system.

[0004] A common anti-pollution system is to regularly heat and degas the cold optical structure. For example, the CrIS (Cross-Orbit Infrared Sounder) on the U.S. polar-orbiting operational environmental satellite NPOESS uses regular heating every year (for several months). The HIRAS-Ⅰ (Infrared Hyperspectral Atmospheric Sounder Type Ⅰ) on my country's polar-orbiting meteorological satellite Fengyun-3D also uses a similar method to regularly heat and decontaminate to restore instrument performance. The disadvantage of this method is that it is necessary to regularly stop the instrument's detection function and perform heating and decontamination at medium temperature (30℃-40℃), which takes a long time and affects the instrument's on-orbit business application. In addition, some organic pollutants cannot be removed by heating. Summary of the invention

[0005] The purpose of the present invention is to provide an anti-pollution system for the cold optical structure of space infrared instruments that can effectively solve the problem of signal attenuation caused by external pollution of the cold optical structure of space infrared instruments and does not require regular baking in orbit to affect business applications.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A pollution prevention device for a cold optical system of a space infrared instrument, used for preventing a room temperature optical structure and a cold optical structure from being interfered with each other by temperature and pollution, comprising a room temperature window pressure plate assembly, a high thermal resistance closed cold trap, a cold window assembly, a cold window pressure plate assembly and a room temperature window assembly; the room temperature window assembly is fixed to the open outer ring of the room temperature optical structure by screws, and the room temperature window assembly connects one end of the high thermal resistance closed cold trap with the open outer ring of the room temperature optical structure through the room temperature window pressure plate assembly; the cold window assembly is fixed to the opening of the cold optical structure by screws, and the cold window assembly connects the other end of the high thermal resistance closed cold trap with the opening of the cold optical structure through the cold window pressure plate assembly; the room temperature optical structure and the cold optical structure are connected through the high thermal resistance closed cold trap to avoid heat leakage of the cold optical structure, thereby preventing the room temperature optical structure and the cold optical structure from being interfered with each other by temperature.

[0008] Preferably, it also includes a cold window heating plate, which is connected to a temperature control circuit or a temperature relay. The cold window heating plate is fixed to the outer wall of the opening of the cold optical structure by gluing and is close to the cold window assembly, so as to heat and contaminate the cold optical structure as needed to prevent the cold window assembly from being contaminated by low-temperature adsorption.

[0009] Preferably, the normal temperature window assembly comprises a normal temperature window shell and a normal temperature window; an inner cavity is provided on the normal temperature window shell, and the normal temperature window is made of infrared material and is fixed in the inner cavity of the normal temperature window shell by gluing or pressing ring; normal temperature window threaded sections with external threads are respectively provided at both ends of the normal temperature window shell for connecting with the normal temperature window pressure plate assembly; a connector for the high thermal resistance closed cold trap is reserved between the normal temperature window threaded section and the normal temperature window shell; one end of the high thermal resistance closed cold trap is fixedly pressed in the connector by the normal temperature window pressure plate assembly and is connected to the normal temperature optical structure.

[0010] Preferably, the normal temperature window pressure plate assembly comprises a threaded pressure ring with an internal thread, a threaded pressure ring back plate 1 and a threaded pressure ring back plate 2; the threaded pressure ring back plate 1 and the threaded pressure ring back plate 2 adopt half pressure rings, which are respectively fixed to the two ends of the threaded pressure ring by countersunk screws, so as to facilitate assembly and integration in a narrow space; the internal thread of the threaded pressure ring is connected to the external thread of the normal temperature window thread segment; one end of the high thermal resistance closed cold trap is fixed through the threaded pressure ring of the circular ring and pressed into the socket, and connected to the normal temperature optical structure.

[0011] Preferably, the cold window assembly comprises a cold window shell and a cold window; an inner cavity is provided on the cold window, and the cold window is fixed in the inner cavity of the cold window shell by using a fluororubber pressure ring or a low outgassing rate epoxy resin glue; cold window flanges are respectively provided at both ends of the cold window shell, and are connected to the other end of the high thermal resistance closed cold trap by using a cold window pressure plate assembly through the cold window flanges.

[0012] Preferably, the cold window pressure plate assembly includes a cold window pressure ring 1 and a cold window pressure ring 2, and the cold window pressure ring 1 and the cold window pressure ring 2 both adopt half-circle pressure rings; the cold window pressure ring 1 and the cold window pressure ring 2 respectively connect the other end of the high thermal resistance closed cold trap to the cold window flange of the cold window assembly through countersunk screws.

[0013] Preferably, the high thermal resistance closed cold trap is made of ultra-thin non-metallic material in a cylindrical or conical shape, and the inner cavity of the high thermal resistance closed cold trap is slightly larger than the light-through aperture; the two ends of the high thermal resistance closed cold trap are fixed and connected to the normal temperature window assembly and the cold window assembly by flanges through the normal temperature window pressure plate assembly and the cold window pressure plate assembly respectively.

[0014] Preferably, the high thermal resistance closed cold trap includes an inclined cone surface and a corrugated surface, the inclined cone surface is connected to the above through flange surface one, and the corrugated surface is connected to the above through a flange transition surface; the corrugated structure of the corrugated surface is used to increase the total length of the transfer path, while increasing the thermal resistance and reducing conduction heat leakage.

[0015] Preferably, the side of the corrugated structure is provided with a venting hole for venting air when the air pressure decreases.

[0016] The present invention also provides an application method of an anti-pollution device for a cold optical system of a space infrared instrument, comprising the following steps:

[0017] The two ends of the high thermal resistance closed cold trap are connected to the normal temperature window and the cold window by using flange surface 1 and flange surface 2 respectively through threaded pressure ring back plate 1 and threaded pressure ring back plate 2 of the normal temperature window pressure plate assembly and cold window pressure ring 1 and cold window pressure ring 2 of the cold window pressure plate assembly, so that the cold optical structure and the normal temperature optical structure are physically isolated from the external normal temperature environment through the high thermal resistance closed cold trap, effectively preventing the entry of external water vapor and condensable volatiles, thereby preventing the volatilization of external organic materials and water vapor from polluting the cold optical light inlet and preventing the instrument performance from attenuating;

[0018] The cold window heating plate is fixed to the open outer wall of the cold optical structure close to the cold window assembly by gluing, and is connected to a temperature control circuit or a temperature relay to provide thermal energy. It is used to heat and remove a small amount of water vapor in the cold optical structure at the beginning of the spacecraft entering orbit. After the spacecraft state stabilizes, no decontamination heating is required, which solves the problem that the spacecraft needs to be regularly decontaminated and heated in orbit, cannot work continuously, and affects business applications.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The use of bellows-type closed cold trap, compared with the method of only setting up a low-temperature open cold trap on the infrared radiation path, which can only absorb part of the pollution, physically isolates the cold optical window from the external environment, basically eliminates the influence of the outside world, and solves the problem that the open cold trap cannot isolate all pollution and cannot avoid the degradation of system performance due to the adsorption of pollution by the cold optical structure.

[0021] 2 Usually, decontamination heating is only required at the initial stage of entering orbit. After the instrument status stabilizes, decontamination heating is no longer required. This solves the problem that the instrument needs to be decontaminated and heated on orbit regularly, cannot work continuously, and affects business applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of an anti-pollution device for a cold optical system of a space infrared instrument provided by an embodiment of the present invention applied to a normal temperature optical structure and a cold optical structure;

[0023] Figure 2 for Figure 1 A schematic diagram of a partial cross-sectional view of the structure;

[0024] Figure 3 for Figure 2 Schematic diagram of the enlarged structure of I.

[0025] Figure 4 for Figure 2 Schematic diagram of the enlarged structure of II;

[0026] Figure 5 A schematic cross-sectional view of a normal temperature window pressure plate assembly in an anti-pollution device for a cold optical system of a space infrared instrument provided by an embodiment of the present invention;

[0027] Figure 6 A schematic cross-sectional structure diagram of a high thermal resistance closed cold trap in an anti-pollution device for a cold optical system of a space infrared instrument provided by an embodiment of the present invention.

[0028] Figure 7 A schematic cross-sectional view of a cold window assembly in an anti-pollution device for a cold optical system of a space infrared instrument provided by an embodiment of the present invention;

[0029] Figure 8 A schematic diagram of the structure of a cold window heater in an anti-pollution device for a cold optical system of a space infrared instrument provided by an embodiment of the present invention;

[0030] Fig. 9A schematic diagram of the three-dimensional structure of a cold window pressing plate assembly in an anti-pollution device for a cold optical system of a space infrared instrument provided by an embodiment of the present invention;

[0031] Fig.10 A schematic cross-sectional view of a cold window pressure plate assembly in an anti-pollution device for a cold optical system of a space infrared instrument provided by an embodiment of the present invention;

[0032] Fig.11 A schematic cross-sectional structure diagram of a normal temperature window assembly in an anti-pollution device for a cold optical system of a space infrared instrument provided by an embodiment of the present invention.

[0033] The serial numbers in the figure are as follows:

[0034] 1. Normal temperature window pressure plate assembly; 101. Threaded pressure ring; 102. Threaded pressure ring back plate; 103. Countersunk screw; 2. High thermal resistance closed cold trap; 201. Flange surface; 202. Beveled cone surface; 203. Corrugated surface; 204. Flange transition surface; 205. Flange surface; 3. Cold window assembly; 301. Cold window flange; 302. Cold window; 4. Cold window heating plate; 5. Cold window pressure plate assembly; 501. Cold window pressure ring 1; 502. Cold window pressure ring 2; 6. Normal temperature window assembly; 601. Normal temperature window shell; 602. Normal temperature window; 603. Normal temperature window threaded section; 7. Normal temperature optical structure; 8. Cold optical structure. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0036] like Figures 1 to 10 As shown, an anti-pollution device for a cold optical system of a space infrared instrument provided in this embodiment is used to prevent mutual temperature and pollution interference between a normal temperature optical structure 7 and a cold optical structure 8, and includes a normal temperature window pressure plate assembly 1, a high thermal resistance closed cold trap 2, a cold window assembly 3, a cold window heating plate 4, a cold window pressure plate assembly 5 and a normal temperature window assembly 6.

[0037] The normal temperature window assembly 6 is fixed to the outer ring of the opening of the normal temperature optical structure 7 by screws, and includes a normal temperature window shell 601 and a normal temperature window 602 .

[0038] An inner cavity is provided on the normal temperature window shell 601, and the normal temperature window 602 is made of infrared material and is fixed in the inner cavity of the normal temperature window shell 601 by gluing or pressing ring; normal temperature window threaded sections 603 with external threads are respectively provided at both ends of the normal temperature window shell 601, which are used to connect with the normal temperature window pressure plate assembly 1; a connector for a high thermal resistance closed cold trap 2 is reserved between the normal temperature window threaded section 603 and the normal temperature window shell 601; one end of the high thermal resistance closed cold trap 2 is fixedly pressed in the connector by the normal temperature window pressure plate assembly 1, and is connected to the normal temperature optical structure 7.

[0039] The normal temperature window pressure plate assembly 1 includes an internally threaded threaded pressure ring 101, a threaded pressure ring back plate 102, and a threaded pressure ring back plate 2 104. The threaded pressure ring back plate 102 and the threaded pressure ring back plate 2 104 are semi-pressure rings, which are respectively fixed to the two ends of the threaded pressure ring 101 by countersunk screws 103, so as to facilitate assembly and integration in a narrow space; the internal thread of the threaded pressure ring 101 is connected with the external thread of the normal temperature window thread section 603; one end of the high thermal resistance closed cold trap 2 is fixed and pressed into the socket through the circular threaded pressure ring 101, and connected with the normal temperature optical structure 7.

[0040] The cold window assembly 3 is fixed to the opening of the cold optical structure 8 by screws, and comprises a cold window shell 303 and a cold window 302; an inner cavity is provided on the cold window 302, and the cold window 302 is fixed in the inner cavity of the cold window shell 303 by using a fluororubber pressure ring or a low outgassing rate epoxy resin glue; cold window flanges 301 are respectively provided at both ends of the cold window shell 303, and the cold window pressure plate assembly 5 is connected to the other end of the high thermal resistance closed cold trap 2 through the cold window flange 301, and the other end of the high thermal resistance closed cold trap 2 is connected to the opening of the cold optical structure 8;

[0041] The cold window pressing plate assembly 5 comprises a cold window pressing ring 1 501 and a cold window pressing ring 2 502, both of which are half-circle pressing rings. The cold window pressing ring 1 501 and the cold window pressing ring 2 502 respectively connect the other end of the high thermal resistance closed cold trap 2 to the cold window flange 301 of the cold window assembly 3 through countersunk screws.

[0042] Normal temperature optics is at room temperature of about 300K, and cold optics temperature is usually between 60K and 250K. The temperature gradient between the two is relatively large. The normal temperature optical structure 7 and the cold optical structure 8 are connected by a high thermal resistance closed cold trap 2 to prevent heat leakage of the cold optical structure 8, thereby preventing the normal temperature optical structure 7 and the cold optical structure 8 from being disturbed by the external temperature. The high thermal resistance closed cold trap 2 can effectively prevent the entry of external water vapor and condensable volatiles, thereby avoiding contamination of the normal temperature window 602 and the cold window 302 close to the high thermal resistance closed cold trap 2.

[0043] The cold window heating plate 4 is connected to a temperature control circuit or a temperature relay. The cold window heating plate 4 is fixed to the outer wall of the opening of the cold optical structure 8 by gluing and is close to the cold window assembly 3. It is used to heat and contaminate the cold optical structure 8 as needed to prevent the cold window 302 of the cold window assembly 3 from being contaminated by low-temperature adsorption. It is used to heat and remove a small amount of water vapor in the cold optical structure 8 when the spacecraft is initially placed into orbit.

[0044] Furthermore, in this embodiment, the high thermal resistance closed cold trap 2 is made of ultra-thin non-metallic material and is cylindrical or conical, and the inner cavity of the high thermal resistance closed cold trap 2 is slightly larger than the aperture. The high thermal resistance closed cold trap 2 includes an oblique cone surface 202 and a corrugated surface 203, the oblique cone surface 202 is connected to 1 through a flange surface 201, and the corrugated surface 203 is connected to 3 through a flange transition surface 204; the corrugated structure of the corrugated surface 203 is used to increase the total length of the transfer path, while increasing the thermal resistance and reducing the conduction heat leakage.

[0045] Furthermore, in this embodiment, a vent hole is provided on the side of the corrugated structure for venting air when the air pressure decreases.

[0046] Furthermore, in this embodiment, the high thermal resistance closed cold trap 2 is made of high thermal resistance and low outgassing rate epoxy fiber with a wall thickness of no more than 0.1 mm, and the 0.1 mm wall thickness is used to significantly increase the thermal resistance of the structure. It is made by molding, injection molding and other processes.

[0047] The present invention provides an application method of the anti-pollution device for a cold optical system of a space infrared instrument, and the method is as follows:

[0048] The two ends of the high thermal resistance closed cold trap 2 are connected to the normal temperature window 602 and the cold window 302 by using the flange surface 1 201 and the flange surface 2 202 respectively through the threaded pressure ring back plate 1 102 and the threaded pressure ring back plate 2 104 of the normal temperature window pressure plate assembly 1 and the cold window pressure ring 1 501 and the cold window pressure ring 2 502 of the cold window pressure plate assembly 5, so that the cold optical structure 8 and the normal temperature optical structure 7 are physically isolated from the external normal temperature environment through the high thermal resistance closed cold trap 2, effectively preventing the external water vapor and condensable volatiles from entering, thereby preventing the volatilization of external organic materials and water vapor from polluting the cold optical light inlet and preventing the instrument performance from attenuating;

[0049] The cold window heating plate 4 is fixed to the open outer wall of the cold optical structure 8 near the cold window assembly 3 by gluing, and is connected to a temperature control circuit or a temperature relay to provide thermal energy, so as to heat and remove a small amount of water vapor in the cold optical structure 8 at the initial stage of the spacecraft entering orbit. After the spacecraft state is stable, no decontamination heating is required, which solves the problem that the spacecraft needs to be regularly decontaminated and heated in orbit, cannot work continuously, and affects business applications.

[0050] The present invention provides an anti-pollution device for a cold optical system of a space infrared instrument. The present invention connects a room temperature window component and a low temperature window component of a space infrared cold optical system with a high thermal resistance non-metallic closed cold trap, so that the cold optical part can be physically isolated from the external room temperature environment, thereby preventing the volatilization of external organic materials and water vapor from polluting the cold optical light inlet and preventing the instrument performance from attenuating. When the low temperature window is realized, a heating plate is used to heat and decontaminate the cold optical window when necessary.

[0051] The present invention connects the normal temperature window component and the low temperature window component of the space infrared cold optical system with a high thermal resistance non-metallic closed cold trap, so that the cold optical part can be physically isolated from the external normal temperature environment, thereby preventing the volatilization of external organic materials and water vapor from polluting the cold optical light inlet and preventing the instrument performance from attenuating. When the low temperature window is not required, the heating plate is used to heat and decontaminate the cold optical window plate when necessary.

[0052] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0054] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An anti-pollution device for a cold optical system of a space infrared instrument, used to prevent a room temperature optical structure (7) and a cold optical structure (8) from being interfered with by temperature and contamination, characterized in that: It comprises a normal temperature window pressing plate assembly (1), a high thermal resistance closed cold trap (2), a cold window assembly (3), a cold window pressing plate assembly (5) and a normal temperature window assembly (6); The normal temperature window component (6) is fixed to the open outer ring of the normal temperature optical structure (7) by means of screws, and the normal temperature window component (6) connects one end of the high thermal resistance closed cold trap (2) to the open outer ring of the normal temperature optical structure (7) through the normal temperature window pressure plate component (1); The cold window assembly (3) is fixed to the opening of the cold optical structure (8) by means of screws, and the cold window assembly (3) connects the other end of the high thermal resistance closed cold trap (2) to the opening of the cold optical structure (8) through the cold window pressing plate assembly (5); The room temperature optical structure (7) and the cold optical structure (8) are connected via the high thermal resistance closed cold trap (2), thereby preventing heat leakage of the cold optical structure (8), and further preventing the room temperature optical structure (7) and the cold optical structure (8) from being affected by mutual temperature interference.

2. The anti-pollution device for a cold optical system of a space infrared instrument according to claim 1, characterized in that: The invention also comprises a cold window heating plate (4), wherein the cold window heating plate (4) is connected to a temperature control circuit or a temperature relay, and the cold window heating plate (4) is fixed to the outer wall of the opening of the cold optical structure (8) by gluing, and is close to the cold window component (3), and is used to heat and pollute the cold optical structure (8) as needed, so as to prevent the cold window component (3) from being polluted by low-temperature adsorption.

3. The anti-pollution device for a cold optical system of a space infrared instrument according to claim 1, characterized in that: The normal temperature window assembly (6) comprises a normal temperature window shell (601) and a normal temperature window (602); The normal temperature window shell (601) is provided with an inner cavity, and the normal temperature window (602) is made of infrared material and is fixed in the inner cavity of the normal temperature window shell (601) by gluing or pressing ring; Both ends of the normal temperature window shell (601) are respectively provided with normal temperature window thread sections (603) with external threads, which are used to be connected to the normal temperature window pressure plate assembly (1); A connector for the high thermal resistance sealed cold trap (2) is reserved between the normal temperature window threaded section (603) and the normal temperature window shell (601); one end of the high thermal resistance sealed cold trap (2) is fixedly pressed into the connector by a normal temperature window pressure plate assembly (1) and connected to the normal temperature optical structure (7).

4. The anti-pollution device for a cold optical system of a space infrared instrument according to claim 3, characterized in that: The normal temperature window pressure plate assembly (1) comprises a threaded pressure ring (101) with internal threads, a threaded pressure ring back plate 1 (102) and a threaded pressure ring back plate 2 (104); The threaded pressure ring back plate 1 (102) and the threaded pressure ring back plate 2 (104) are semi-pressure rings, which are fixed to the two ends of the threaded pressure ring (101) by countersunk screws (103) respectively, so as to facilitate assembly and integration in a narrow space; the internal thread of the threaded pressure ring (101) is connected with the external thread of the normal temperature window thread section (603); one end of the high thermal resistance closed cold trap (2) passes through the circular threaded pressure ring (101) to be fixed and pressed into the socket, and is connected with the normal temperature optical structure (7).

5. The anti-pollution device for cold optical system of space infrared instrument according to claim 1, characterized in that: The cold window assembly (3) comprises a cold window shell (303) and a cold window (302); The cold window (302) is provided with an inner cavity, and the cold window (302) is fixedly arranged in the inner cavity of the cold window shell (303) by using a fluororubber pressure ring or a low outgassing rate epoxy resin glue; The two ends of the cold window shell (303) are respectively provided with cold window flanges (301), and are connected to the other end of the high thermal resistance closed cold trap (2) via the cold window flanges (301) using a cold window pressure plate assembly (5).

6. The anti-pollution device for a cold optical system of a space infrared instrument according to claim 5, characterized in that: The cold window pressing plate assembly (5) comprises a cold window pressing ring 1 (501) and a cold window pressing ring 2 (502), wherein the cold window pressing ring 1 (501) and the cold window pressing ring 2 (502) are both half-circle pressing rings; The cold window pressing ring 1 (501) and the cold window pressing ring 2 (502) respectively connect the other end of the high thermal resistance closed cold trap (2) to the cold window flange (301) of the cold window assembly (3) through countersunk screws.

7. The anti-pollution device for cold optical system of space infrared instrument according to claim 1, characterized in that: The high thermal resistance closed cold trap (2) is made of ultra-thin non-metallic material and is cylindrical or conical, and the inner cavity of the high thermal resistance closed cold trap (2) is slightly larger than the light aperture; The two ends of the high thermal resistance closed cold trap (2) are fixed and connected to the normal temperature window assembly (6) and the cold window assembly (3) respectively through the normal temperature window pressure plate assembly (1) and the cold window pressure plate assembly (5) by means of flanges.

8. The anti-pollution device for a cold optical system of a space infrared instrument according to claim 7, characterized in that: The high thermal resistance closed cold trap (2) comprises an inclined conical surface (202) and a corrugated surface (203), wherein the inclined conical surface (202) is connected to the 1 via a flange surface 1 (201), and the corrugated surface (203) is connected to the 3 via a flange transition surface (204); The corrugated structure of the corrugated surface (203) is used to increase the total length of the transfer path, while increasing the thermal resistance and reducing conduction heat leakage.

9. The anti-pollution device for a cold optical system of a space infrared instrument according to claim 8, characterized in that: The side of the corrugated structure is provided with a vent hole for venting air when the air pressure decreases.

10. An application method of the anti-pollution device for a cold optical system of a space infrared instrument according to any one of claims 1 to 9, characterized in that: The steps include: The two ends of the high thermal resistance closed cold trap (2) are connected to the normal temperature window (602) and the cold window (302) by means of flange surface 1 (201) and flange surface 2 (202) respectively through threaded pressure ring back plate 1 (102) and threaded pressure ring back plate 2 (104) of the normal temperature window pressure plate assembly (1) and cold window pressure ring 1 (501) and cold window pressure ring 2 (502) of the cold window pressure plate assembly (5), so that the cold optical structure (8) and the normal temperature optical structure (7) are physically isolated from the external normal temperature environment through the high thermal resistance closed cold trap (2), effectively preventing the entry of external water vapor and condensable volatiles, thereby preventing the volatilization of external organic materials and water vapor from polluting the cold optical light inlet and preventing the instrument performance from being degraded; The cold window heating sheet (4) is fixed to the outer wall of the opening of the cold optical structure (8) near the cold window assembly (3) by gluing, and is connected to a temperature control circuit or a temperature relay to provide heat energy, and is used to heat and remove a small amount of water vapor in the cold optical structure (8) at the initial stage of the spacecraft entering orbit. After the spacecraft is in a stable state, decontamination heating is no longer required, thereby solving the problem that the spacecraft needs to be regularly decontaminated and heated on orbit, cannot work continuously, and affects business applications.

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