Built-in large aperture 20k cold shield structure and mounting method

Abstract

The application provides a built-in large-diameter 20K cold screen structure and a mounting method, which comprises a cold screen arranged in a vacuum low-temperature ring mold equipment, a sealing tail cover and a small-diameter sealing pipeline, the sealing tail cover is detachably mounted in the ring mold equipment, the cold screen is detachably mounted outside the sealing tail cover, the sealing tail cover is sealingly mounted with the ring mold equipment through the small-diameter sealing pipeline, and a space with atmospheric air on the inside and vacuum low-temperature environment on the outside is formed. The cold screen is mounted in the ring mold equipment to form a built-in 20K cold screen structure, small-diameter mounting is realized, the requirement for the size of the mounting interface of the ring mold equipment is effectively reduced, even if the ring mold equipment has been completed, as long as a Φ200 mounting interface is reserved, the 20K cold screen device can be additionally provided, and great convenience is provided for mounting the 20K cold screen on the ring mold equipment.

Description

Technical Field

[0001] This invention relates to the field of spacecraft environment simulation equipment technology, specifically to a built-in large-diameter 20K cold screen structure and its installation method. Background Technology

[0002] Before launch, spaceborne infrared remote sensing instruments must undergo infrared radiation calibration tests in a dedicated large-scale space environment simulator capable of simulating corresponding space environment conditions, Earth's radiation characteristics, and the characteristics of reflected solar radiation. This calibration determines the mathematical relationship between the output signals of each detection channel and the target's physical parameters, and verifies the normal operation of the instrument's detection channels, as well as determining the dynamic range of the channels. Generally, in addition to a vacuum cryogenic environment, spaceborne remote sensors also require a localized cold background below 25K, typically obtained using a 20K cold screen.

[0003] Currently, cooling and maintaining the low temperature of 20K cold shields generally employs helium turbine expansion refrigeration systems or GM refrigerators as the cold source. Helium turbine expansion refrigeration systems are complex in structure, have high construction costs, and poor operational stability. In contrast, using GM refrigerators to cool the cold shields relies on heat conduction between the refrigerator's cold head and the shield, avoiding complex operations, offering high reliability, and lower construction costs. Therefore, GM refrigerators are currently the most commonly used cold source for 20K cold shields. Because the cooling capacity of a single GM refrigerator is relatively small, depending on the size of the cold shield and the required cooling capacity, 5 to 10 GM refrigerators are often needed simultaneously for cooling.

[0004] A patent document with publication number CN102009748A discloses a 20K cold screen cooling device, comprising: a GM refrigerator

[26] mounted on an installation fixture

[25] via a vacuum sealing surface; a cold screen shielding plate

[23] connected to the first-stage cold head

[24] of the GM refrigerator

[26] ; and a 20K cold screen

[21] securely connected to the second-stage cold head

[22] of the GM refrigerator

[26] . The aforementioned 20K cold screen cooling device is vacuum-sealed and installed on the top of a vacuum simulation chamber

[12] via the installation fixture

[25] .

[0005] Existing patent document CN112178967A discloses a multi-angle mounting structure suitable for cold screens, including: a spring adjustment device, a sliding rod swing device, a cold screen plate support column, a cold screen plate, and a cold head structure; wherein, a cold screen plate support column is provided on the cold screen plate, and the cold screen plate support column defines the position of the cold screen plate; the spring adjustment device and the sliding rod swing device are respectively connected to the cold head structure; the spring adjustment device can balance the gravity of the cold head structure when the cold head structure is not horizontally installed; the sliding rod swing device defines the position of the cold head structure.

[0006] Both patent documents mentioned above employ external mounting, requiring a mounting flange hole of at least Φ1500mm to be provided on the vacuum container of the ring die equipment. Installing a large-diameter mounting flange on the vacuum container requires specialized technology and is costly. Furthermore, ring die equipment that has already been constructed rarely has mounting flange holes larger than Φ1000mm pre-drilled; typically, the pre-drilled flange diameter is around Φ200. Secondly, the current structure allows the cold shield to be installed in a fixed position, making positional adjustments impossible. Moreover, the cold head mounting cavity lacks temperature control, easily leading to condensation and other sealing surface leakage problems caused by low temperatures. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a built-in large-diameter 20K cold screen structure and installation method.

[0008] According to the present invention, a built-in large-diameter 20K cold shield structure includes a cold shield, a sealing tail cover and a small-diameter sealing pipeline disposed in a vacuum cryogenic ring mold device. The sealing tail cover is detachably installed inside the ring mold device and the cold shield is detachably installed outside the sealing tail cover.

[0009] The sealed tail cover is installed in a sealed manner with the ring mold equipment through a small-diameter sealed pipeline, forming a space where the inside is atmospheric and the outside is a vacuum low-temperature environment.

[0010] Preferably, the ring die device has a detachable support structure installed inside, and the sealing tail cover is fixed on the support structure.

[0011] Preferably, the sealing tail cover includes a cold head mounting base, a sealing blind plate, a pipe connection flange, a cold head mounting flange, and a saddle.

[0012] The sealing blind plate is detachably connected to the cold head mounting base. The cold head mounting base is provided with a cold head mounting flange. The pipeline connection flange is provided on the cold head mounting base or the detachable sealing blind plate. One end of the saddle is fixed to the cold head mounting base, and the other end of the saddle is fixedly connected to the ring die equipment.

[0013] Preferably, it also includes a GM refrigerator, which includes a cold head, a helium hose, and a helium compressor;

[0014] The cold head is installed on the outside of the sealed tail cover, the helium compressor is installed outside the ring die equipment, the helium hose connects the helium compressor and the cold head, and the helium hose is led out from inside the sealed tail cover through a small-diameter sealed pipeline and connected to the helium compressor.

[0015] Preferably, the cold head includes a cooling end and a helium tube mounting end. The cooling end is located on the vacuum cryogenic side, and the helium tube mounting end is located on the atmospheric side inside the sealed tail cover. The helium tube mounting end is connected to the helium compressor via a helium hose.

[0016] Preferably, the cold screen includes a cold screen substrate, an emitting surface, a cold screen support rod, and a thermal bridge; the emitting surface is fixed on the cold screen substrate, the cold screen substrate is fixed outside the sealed tail cover by the cold screen support rod, and the cold screen substrate is connected to the cooling end by the thermal bridge.

[0017] Preferably, the emitting surface includes a pyramidal emitting surface or a honeycomb emitting surface;

[0018] Both the cold screen substrate and the emitting surface are coated with black paint.

[0019] Preferably, it also includes a tail cover heating device, which includes a heating fan and an air supply duct, wherein the heating fan supplies heated air into the sealed tail cover through the air supply duct.

[0020] Preferably, both the low-temperature vacuum side of the small-diameter sealed pipeline and the low-temperature vacuum side of the sealed tail cover are covered with an insulation layer.

[0021] This invention provides an installation method for a built-in large-diameter 20K cold screen structure, comprising:

[0022] Step S1: Determine the position of the sealing tail cover inside the ring die equipment;

[0023] Step S2: Fabricate a small-diameter sealing pipe that matches the sealing tail cover;

[0024] Step S3: Install the sealing tail cover and the cold shield. Install the sealing tail cover inside the ring die equipment and install the cold shield on the cold head mounting base of the sealing tail cover.

[0025] Step S4: Install the GM refrigerator, install the cold head on the cold head mounting base of the sealed tail cover, with the cooling end located on the vacuum low-temperature side and connected to the cold shield, and the helium tube mounting end located on the atmospheric side of the sealed tail cover and connected to the helium compressor.

[0026] Step S5: Install the tail cover heating device.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention achieves small-diameter installation by installing the cold shield inside the ring mold equipment to form a built-in 20K cold shield structure, effectively reducing the requirements for the installation interface size of the ring mold equipment. Even if the ring mold equipment has been completed, as long as an installation interface of about Φ200 is reserved, a 20K cold shield device can be added, which greatly facilitates the installation of 20K cold shields on the ring mold equipment.

[0029] 2. This invention installs a 20K cold shield using a sealed tail cover. The 20K cold shield can be installed at any position as needed. After the position of the sealed tail cover is confirmed, only matching small-diameter sealed pipes need to be made and the support structure inside the ring mold equipment needs to be adjusted to achieve the installation. By making different small-diameter sealed pipes and adjusting the support structure, the 20K cold shield can be installed at any position, which can economically realize the multi-angle and multi-position use of the 20K cold shield.

[0030] 3. This invention connects the cold head to the cold screen by installing the cold head on the vacuum low-temperature side of the sealed tail cover and installing the helium tube installation end on the atmospheric side inside the sealed tail cover. This is beneficial for the cold head to supply cooling to the cold screen and for temperature control of the cold head installation cavity. It also solves the problems of condensation in the cold head installation cavity and leakage of the sealing surface caused by low temperature.

[0031] 4. By introducing a tail cover heating device, the present invention has more complete functions and can effectively control the temperature of the sealed tail cover, avoiding condensation and other leakage problems caused by low temperature.

[0032] 5. This invention features a detachable structure for the cold shield, GM refrigeration unit, and sealing tail cover, making maintenance convenient and facilitating the disassembly, relocation, and subsequent maintenance of the device. Users can choose whether to remove or change the installation position as needed. Attached Figure Description

[0033] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0034] Figure 1 This is a schematic diagram of the built-in 20K cold screen structure of the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of the sealing tail cover of the present invention;

[0036] Figure 3 Schematic diagram of the GM refrigerator structure of this invention;

[0037] Figure 4 This is a schematic diagram of the cold screen structure of the present invention;

[0038] Figure 5 This is a schematic diagram of the tail cover heating device.

[0039] As shown in the figure:

[0040] Ring mold equipment 1, sealing tail cover 4, cooling end 511

[0041] Support structure 11 Cold head mounting base 41 Helium tube mounting end 512

[0042] Small-diameter sealed pipeline 2; Sealed blind flange 42; Helium hose 52

[0043] Cold screen 3, Pipe connection flange 43, Helium compressor 53

[0044] 31 Cold shield substrate; 44 Cold head mounting flange; 6 Tail cover heating device

[0045] Launch surface 32, saddle 45, heating fan 61

[0046] Cold screen support rod 33, GM refrigeration unit 5, air supply duct 62

[0047] Thermal bridge 34, cold head 51 Detailed Implementation

[0048] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0049] like Figure 1 As shown, a built-in 20K cold shield structure provided by the present invention includes a small-diameter sealed pipe 2, a cold shield 3, a sealed tail cover 4, a GM refrigeration unit 5, and a tail cover heating device 6.

[0050] The entire device is installed inside a vacuum cryogenic ring mold device 1. The sealed tail cover 4 is fixed inside the ring mold device 1 by a support structure 11 within the ring mold device 1. It is sealed to the ring mold device 1 via a small-diameter sealed pipe 2, forming a space where the inner side is atmospheric and the outer side is a vacuum cryogenic environment. The sealed tail cover 4 can be installed at any position as needed. Once the position of the sealed tail cover 4 is confirmed, only a matching small-diameter sealed pipe 2 needs to be fabricated, and the support structure 11 within the ring mold device 1 needs to be adjusted to achieve installation. By fabricating different small-diameter sealed pipes 2 and adjusting the support structure 11, the 20K cold screen can be installed at any position. The cold head 51 of the GM refrigerator 5 is installed on the cold head mounting base 41 of the sealed tail cover 4. The cooling end 511 is located on the vacuum cryogenic side and connected to the cold screen 3. The helium tube mounting end 512 is located on the atmospheric side of the sealed tail cover 4 and connected to the helium compressor 53. A tail cover heating device 6 is provided on the atmospheric side of the sealed tail cover 4 to control the atmospheric side at room temperature.

[0051] The sealing tail cover 4 is generally cylindrical, but square or other structures are also possible. The sealing tail cover 4 includes a cold head mounting base 41, a removable sealing blind flange 42, a pipe connection flange 43, a cold head mounting flange 44, and a saddle 45. The cold head mounting flange 44 is mounted on the cold head mounting base 41 for mounting the cold head 51. The pipe connection flange 43 (generally around φ200mm) can be mounted on the cold head mounting base 41 or the removable sealing blind flange 42 for connecting the sealing pipe 2. The bottom of the sealing tail cover 4 is the saddle 45, used for connection and fixation with the ring die equipment 1.

[0052] The GM refrigeration unit 5 includes a cold head 51, a helium compressor 53, and a helium hose 52. The helium compressor 53 is connected to the cold head 51 by the helium hose 52. The cold head 51 is mounted on the cold head mounting base 41 of the sealed tail cover 4, and the helium compressor 53 is mounted outside the ring mold equipment 1. The helium hose 52 is led out from inside the sealed tail cover 4 through the sealed pipeline 2 and connected to the helium compressor 53 outside the ring mold equipment 1.

[0053] The cold screen 3 includes a cold screen substrate 31, an emitting surface 32, a cold screen support rod 33, and a heat-conducting bridge 34. The cold screen substrate 31 and the emitting surface 32 can be integrally manufactured from the same material or welded from different materials. The materials used to manufacture the cold screen substrate 31 and the emitting surface 32 include, but are not limited to, stainless steel, aluminum alloy, and oxygen-free copper. The structure of the emitting surface 32 can be either a square pyramid or a honeycomb shape. The cold screen substrate 31 and the emitting surface 32 are typically coated with a special black paint with a high absorption ratio.

[0054] The cold screen 3 is fixed to the outside of the cold head mounting base 41 of the sealed tail cover 4 by the cold screen support rod 33. The cold screen 3 is connected to the cooling end 511 of the cold head by the thermal bridge 34. The thermal bridge 34 is generally made of copper or a material with better thermal conductivity, and can be a rigid connection or a flexible connection.

[0055] The vacuum side of the small-diameter sealed pipe 2 and the vacuum side of the sealed tail cover 4 are both covered with multiple layers of high-reflectivity heat insulation layer to reduce the transfer of cold energy radiated from the vacuum low-temperature environment to the atmospheric side through the sealed tail cover 4, which would cause condensation or frost.

[0056] The tail cover heating device 6 has an automatic temperature control function, including a heating fan 61 and an air supply duct 62. Its main function is to control the atmospheric side of the sealed tail cover 4 at room temperature to avoid condensation and other leakage problems caused by low temperature. The heating fan 61 sends heated air into the sealed tail cover 4 through the air supply duct 62. Heating can also be achieved by arranging heating elements or heating wires inside the sealed tail cover.

[0057] The present invention provides a built-in 20K cold shield structure and installation method, which has the advantages of small installation interface size, economical installation in any position, complete functions, and convenient disassembly and assembly. It solves the problems of small diameter, multi-position installation, low temperature condensation or other sealing surface leakage caused by low temperature for large-diameter 20K cold shields.

[0058] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0059] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A built-in 20K cold screen structure, characterized in that, It includes a cold screen (3), a sealing tail cover (4) and a small-diameter sealing pipeline (2) installed in the vacuum cryogenic ring mold equipment (1). The sealing tail cover (4) is detachably installed inside the ring mold equipment (1), and the cold screen (3) is detachably installed outside the sealing tail cover (4). The sealed tail cover (4) is sealed and installed with the ring mold equipment (1) through a small-diameter sealed pipe (2), forming a space with the atmosphere on the inside and a vacuum low-temperature environment on the outside; It also includes a GM refrigerator (5), which includes a cold head (51), a helium hose (52) and a helium compressor (53); The cold head (51) is installed on the outside of the sealing tail cover (4), the helium compressor (53) is installed outside the ring die device (1), the helium hose (52) connects the helium compressor (53) and the cold head (51), and the helium hose (52) is led out from the sealing tail cover (4) through the small diameter sealing pipe (2) and connected to the helium compressor (53); The cold head (51) includes a cooling end (511) and a helium tube mounting end (512). The cooling end (511) is located on the vacuum cryogenic side, and the helium tube mounting end (512) is located on the atmospheric side inside the sealed tail cover (4). The helium tube mounting end (512) is connected to the helium compressor (53) through a helium hose (52).

2. The built-in 20K cold screen structure as described in claim 1, characterized in that, The ring die device (1) has a detachable support structure (11) installed inside, and the sealing tail cover (4) is fixed on the support structure (11).

3. The built-in 20K cold screen structure as described in claim 1, characterized in that, The sealing tail cover (4) includes a cold head mounting base (41), a sealing blind plate (42), a pipeline connection flange (43), a cold head mounting flange (44), and a saddle (45). The sealing blind plate (42) is detachably connected to the cold head mounting base (41). The cold head mounting base (41) is provided with a cold head mounting flange (44). The pipeline connection flange (43) is provided on the cold head mounting base (41) or the detachable sealing blind plate (42). One end of the saddle (45) is fixed to the cold head mounting base (41), and the other end of the saddle (45) is fixedly connected to the ring mold device (1).

4. The built-in 20K cold screen structure as described in claim 1, characterized in that, The cold screen (3) includes a cold screen substrate (31), an emitting surface (32), a cold screen support rod (33), and a heat-conducting bridge (34). The emitting surface (32) is fixed on the cold screen substrate (31). The cold screen substrate (31) is fixed outside the sealing tail cover (4) by the cold screen support rod (33). The cold screen substrate (31) is connected to the cooling end (511) by the heat-conducting bridge (34).

5. The built-in 20K cold screen structure as described in claim 4, characterized in that, The emitting surface (32) includes a square pyramidal emitting surface or a honeycomb emitting surface; Both the cold screen substrate (31) and the emitting surface (32) are coated with black paint.

6. The built-in 20K cold screen structure as described in claim 1, characterized in that, It also includes a tail cover heating device (6), which includes a heating fan (61) and an air supply pipe (62). The heating fan (61) sends heated air into the sealed tail cover (4) through the air supply pipe (62).

7. The built-in 20K cold screen structure as described in claim 1, characterized in that, The low-temperature vacuum side of the small-diameter sealed pipeline (2) and the low-temperature vacuum side of the sealed tail cover (4) are both covered with an insulation layer.

8. A method for installing a built-in 20K cold screen structure, based on the built-in 20K cold screen structure according to any one of claims 1-7, characterized in that, include: Step S1: Determine the position of the sealing tail cover (4) inside the ring die equipment (1); Step S2: Fabricate a small-diameter sealing pipe (2) that matches the sealing tail cover (4); Step S3: Install the sealing tail cover (4) and the cold screen (3). Install the sealing tail cover (4) inside the ring die equipment (1) and install the cold screen (3) on the cold head mounting base (41) of the sealing tail cover (4). Step S4: Install the GM refrigerator (5), install the cold head (51) on the cold head mounting base (41) of the sealed tail cover (4), the refrigeration end (511) is located on the vacuum low temperature side and connected to the cold screen (3), and the helium tube mounting end (512) is located on the atmospheric side of the sealed tail cover (4) and connected to the helium compressor (53). Step S5: Install the tail cover heating device (6).

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