Temperature and pressure environment test chamber and test method thereof

Abstract

The invention belongs to the technical field of low-temperature facility environment testing, and discloses a temperature and pressure environment test chamber and a test method thereof. The main body of the temperature and pressure environment test chamber is a test chamber body, and an external gas inlet branch on the test chamber body is used for conveying gas to the test chamber body; the air pressure adjusting branch is used for adjusting the pressure of the air inlet branch; the exhaust branch is used for exhausting gas in the test cabin body; the circulating gas branch is used for gas circulation in the test cabin body; the liquid nitrogen injection branch comprises a liquid nitrogen injection branch and a liquid nitrogen discharge branch, the liquid nitrogen injection branch is used for injecting liquid nitrogen into the test cabin, and the liquid nitrogen discharge branch is used for discharging nitrogen of the liquid nitrogen buffer tank. The test method comprises an air temperature and pressure environment test method and a nitrogen temperature and pressure environment test method. The temperature and pressure environment test chamber and the test method thereof are applied to the field of large low-temperature facilities and the field of temperature and pressure test such as aerospace exploration, plateau environment and high-altitude environment, and have practical value.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-temperature facility environmental testing, and in particular relates to a temperature and pressure environmental testing chamber and a testing method thereof. Background Art

[0002] Cryogenic test balances are required to conduct low-temperature loading tests, measuring the response curves of low-temperature strain gauges under different loads, temperatures, and pressures to obtain accurate calibration test data. Cryogenic testing requires the development of various testing technologies. For low-temperature wing flutter testing, to ensure safety, flutter material properties must be tested in a temperature-switching environment of 110K to 293K, combined with test pressure, before the test begins. These tests examine the material's elastic and mechanical properties, strength, and frequency. Furthermore, the development and improvement of testing technologies such as low-temperature PIV tracer particles, low-temperature model deformation measurement, and low-temperature thermal jets require environmental testing equipment that can withstand varying temperatures and pressures.

[0003] Existing environmental simulation equipment is generally designed for low-altitude or space environment simulation, but rarely for alternating positive and negative pressures. This alternating pressure poses new challenges to sealing and process flow. Currently, there is an urgent need to develop a temperature and pressure environmental test chamber and its testing methods. Summary of the Invention

[0004] One technical problem to be solved by the present invention is to provide a temperature and pressure environment test chamber. Another technical problem to be solved by the present invention is to provide a test method for a temperature and pressure environment test chamber.

[0005] The main body of the temperature and pressure environment test chamber of the present invention is a test chamber body, which is externally connected to an air intake branch, an air pressure regulating branch, an exhaust branch, a circulating gas branch, and a liquid nitrogen injection branch; the air intake branch is used to transport gas to the test chamber body; the air pressure regulating branch is used to regulate the pressure of the air intake branch; the exhaust branch is used to discharge gas from the test chamber body; the circulating gas branch is used for gas circulation in the test chamber body; the liquid nitrogen injection branch includes a liquid nitrogen injection branch and a liquid nitrogen discharge branch, the liquid nitrogen injection branch is used to inject liquid nitrogen into the test chamber body, and the liquid nitrogen discharge branch is used to discharge nitrogen from the liquid nitrogen buffer tank.

[0006] Furthermore, the air intake branch includes an air intake branch and a nitrogen intake branch connected in parallel; the air intake branch includes a dry air buffer tank, a manual stop valve and an electric stop valve connected in sequence through a pipeline along the airflow direction, and the nitrogen intake branch includes a dry air buffer tank, a manual stop valve and an electric stop valve connected in sequence through a pipeline along the airflow direction; thereafter, the air intake branch and the nitrogen intake branch are merged into an intake pipeline connected to the test cabin, and the intake pipeline includes a filter, a pressure sensor, a pressure gauge, an electric regulating valve, a manual stop valve, a pressure gauge and a pressure sensor connected in sequence through a pipeline along the airflow direction.

[0007] Furthermore, the starting point of the air pressure regulating branch is connected to the manual stop valve of the air intake pipe; the air pressure regulating branch includes a manual stop valve, a pressure gauge, a pressure sensor, an electric heater, an electric stop valve, a manual stop valve and a vacuum pump group connected in sequence through the pipe along the air flow direction, and a filter connected to the atmosphere in parallel through the electric regulating valve behind the pressure gauge of the air pressure regulating branch; the vacuum pump group adopts a two-stage vacuum pumping mode of vacuum system and high vacuum system.

[0008] Furthermore, the exhaust branch includes an electric regulating valve, a manual stop valve, a pressure gauge, a pressure sensor and a gas nitrogen exhaust pipe which are sequentially connected through pipelines along the airflow direction.

[0009] Furthermore, the circulating gas branch uses the test chamber as the starting point and end point of the gas circulation, and includes an electric regulating valve, a manual stop valve, a pressure gauge, a temperature sensor, an electric heater and a liquid nitrogen evaporator connected in parallel through a pipeline along the airflow direction, as well as a circulating fan, a temperature sensor and a pressure sensor; wherein, the electric heater and the liquid nitrogen evaporator are respectively provided with independent electric stop valves.

[0010] Furthermore, the liquid nitrogen injection branch includes a liquid nitrogen buffer tank, a manual stop valve, an electric regulating valve and a pressure sensor connected in sequence through a pipeline along the airflow direction; the liquid nitrogen discharge branch includes a manual stop valve, an electric regulating valve, a pressure sensor, a liquid nitrogen evaporator, a manual stop valve, an electric regulating valve and a gas nitrogen discharge pipe connected in sequence through a pipeline along the airflow direction.

[0011] The test method of the temperature and pressure environment test chamber of the present invention includes an air temperature and pressure environment test method and a nitrogen temperature and pressure environment test method; The air temperature and pressure environment test method comprises the following steps: S11. Dry air is introduced into the test chamber from the dry air buffer tank. After standing for exchange, dry air is discharged into the environment through the nitrogen exhaust pipe. This cycle should be repeated at least 20 times until the dew point of the test chamber is below -75°C. S12. The liquid nitrogen buffer tank discharges nitrogen through the liquid nitrogen evaporator to the nitrogen gas discharge pipe, achieving liquid nitrogen evaporation and dry air cooling in the test chamber; S13. The test chamber is cooled by a circulating fan, which regulates the flow of liquid nitrogen from the liquid nitrogen buffer tank using an electric control valve. Once the test chamber reaches a predetermined temperature, the temperature is maintained within a pre-set tolerance. S14. When the test chamber temperature needs to be raised, close the liquid nitrogen buffer tank, turn on the electric heater, and use the circulating fan to ensure internal air flow. Control the heating rate by adjusting the power of the electric heater. Once the test chamber temperature reaches the desired level, maintain the temperature within a pre-set tolerance. S15. When the test chamber pressure needs to be increased, dry air is injected through the dry air buffer tank. The pressure on the pressure gauge is monitored and the amount of dry air introduced is controlled to ensure that the pressure remains stable within the preset range. S16. The initial air is room-temperature dry air at 273K to 293K. The pressure of the test chamber must be reduced. If the actual pressure of the test chamber is greater than atmospheric pressure, close the manual and electric shutoff valves on the air intake branch, open the electric regulating valve and manual shutoff valve connected to the nitrogen exhaust pipe, and ensure that the pressure decreases at the preset pressure reduction rate. If the pressure is less than atmospheric pressure, close the manual and electric shutoff valves on the air intake branch, open the vacuum pump assembly on the pressure regulating branch, and pump air outward to ensure that the pressure decreases at the preset pressure reduction rate. S17. The initial air is cryogenic air at a temperature of 77K to 273K. The pressure of the test chamber must be reduced. If the actual pressure of the test chamber is greater than atmospheric pressure, close the manual and electric shutoff valves on the air intake branch, open the electric regulating valve and manual shutoff valve connected to the nitrogen exhaust pipe, and ensure that the pressure decreases at the pre-set pressure reduction rate. If the actual pressure of the test chamber is less than atmospheric pressure, close the manual and electric shutoff valves on the air intake branch, open the vacuum pump assembly on the pressure regulating branch, and simultaneously turn on the electric heater to draw air outward, ensuring that the pressure decreases at the pre-set pressure reduction rate. The nitrogen temperature and pressure environment test method comprises the following steps: S21. Use the nitrogen distribution table to introduce dry nitrogen into the test chamber. After standing for exchange, discharge the nitrogen gas into the environment through the nitrogen discharge pipe. Repeat this cycle for at least 10 times until the nitrogen content in the test chamber is greater than 99% and the dew point is below -90°C. S22. A liquid nitrogen buffer tank sprays liquid nitrogen into the test chamber. A circulating fan ensures nitrogen flow within the chamber. An electric regulating valve adjusts the flow rate of liquid nitrogen from the liquid nitrogen buffer tank to control the cooling rate. When the chamber temperature reaches the predetermined range of 77K to 293K, the temperature is maintained within a pre-set tolerance. S23. When the test chamber temperature needs to be raised, close the liquid nitrogen buffer tank, turn on the electric heater, and use the circulating fan to ensure nitrogen flow inside. Control the heating rate by adjusting the power of the electric heater. When the test chamber temperature reaches the predetermined temperature, maintain the temperature within the preset error range. S24. When the test chamber pressure needs to be increased, close the dry air buffer tank, open the nitrogen distribution station, and inject dry nitrogen into the test chamber. Monitor the pressure on the pressure gauge and control the amount of dry nitrogen introduced to ensure that the pressure remains stable within the preset range. S25. When the test chamber pressure needs to be reduced, if the initial nitrogen atmosphere is room temperature dry nitrogen at 273K to 293K, turn on the vacuum pump assembly to pump nitrogen outward, ensuring that the pressure decreases at the pre-set pressure reduction rate. S26. When the pressure of the test chamber needs to be reduced, if the initial nitrogen is low-temperature nitrogen at 77K~273K, close the manual shut-off valve and electric shut-off valve of the nitrogen inlet branch, turn on the vacuum pump unit of the air pressure regulating branch, and turn on the electric heater at the same time to heat the nitrogen to avoid damaging the vacuum pump unit. Draw nitrogen out to ensure that the pressure drops according to the pre-set pressure reduction rate.

[0012] The temperature and pressure environment test chamber and the test method thereof of the present invention are suitable for environmental testing of large-scale low-temperature facilities and can carry out temperature and pressure tests using air or nitrogen as the medium. During the test, the temperature can be precisely adjusted between 77K and 293K, with a wide adjustment range and fast adjustment speed; the pressure can be adjusted between 1Pa and 450KPa, and the pressure adjustment range covers positive and negative pressures. It can also simultaneously meet the alternating changes of temperature of 77K to 293K and pressure of 1Pa to 450KPa under extreme conditions, providing a technical platform for key test technology research such as special test technology testing, near-space aircraft verification testing, and extreme environment equipment reliability testing.

[0013] The temperature and pressure environment test chamber and the test method thereof of the present invention are applicable to temperature and pressure test fields such as large-scale low-temperature facilities, aerospace exploration, plateau environments, and high-altitude environments, and have practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0015] Figure 1 It is a structural schematic diagram of the temperature and pressure environment test chamber of the present invention.

[0016] In the figure, 1. filter; 2. electric regulating valve; 3. manual stop valve; 4. pressure gauge; 5. pressure sensor; 6. electric heater; 7. electric stop valve; 8. vacuum pump unit; 9. dry air buffer tank; 10. nitrogen distribution table; 11. test chamber; 12. temperature sensor; 13. gas nitrogen exhaust pipe; 14. liquid nitrogen buffer tank; 15. circulation fan; 16. liquid nitrogen evaporator. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0018] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0019] Example: Figure 1 As shown, the main body of the temperature and pressure environment test chamber of this embodiment is the test chamber body 11, and the test chamber body 11 is externally connected with an air intake branch, an air pressure regulating branch, an exhaust branch, a circulating gas branch and a liquid nitrogen injection branch; the air intake branch is used to transport gas to the test chamber body 11; the air pressure regulating branch is used to regulate the pressure of the air intake branch; the exhaust branch is used to discharge the gas in the test chamber body 11; the circulating gas branch is used for gas circulation in the test chamber body 11; the liquid nitrogen injection branch includes a liquid nitrogen injection branch and a liquid nitrogen discharge branch, the liquid nitrogen injection branch is used to inject liquid nitrogen into the test chamber body 11, and the liquid nitrogen discharge branch is used to discharge nitrogen from the liquid nitrogen buffer tank 14.

[0020] Furthermore, the air intake branch includes an air intake branch and a nitrogen intake branch connected in parallel; the air intake branch includes a dry air buffer tank 9, a manual stop valve 3 and an electric stop valve 7 connected in sequence through a pipe in the direction of the air flow, and the nitrogen intake branch includes a dry air buffer tank 9, a manual stop valve 3 and an electric stop valve 7 connected in sequence through a pipe in the direction of the air flow; thereafter, the air intake branch and the nitrogen intake branch are merged into an intake pipe connected to the test chamber 11, and the intake pipe includes a filter 1, a pressure sensor 5, a pressure gauge 4, an electric regulating valve 2, a manual stop valve 3, a pressure gauge 4 and a pressure sensor 5 connected in sequence through a pipe in the direction of the air flow.

[0021] Furthermore, the starting point of the air pressure regulating branch is connected to the manual stop valve 3 of the air intake pipe; the air pressure regulating branch includes a manual stop valve 3, a pressure gauge 4, a pressure sensor 5, an electric heater 6, an electric stop valve 7, a manual stop valve 3 and a vacuum pump group 8 connected in sequence through a pipe along the air flow direction, and a filter 1 connected to the atmosphere in parallel through an electric regulating valve 2 behind the pressure gauge 4 of the air pressure regulating branch; the vacuum pump group 8 adopts a two-stage vacuum pumping mode of a vacuum system and a high vacuum system.

[0022] Furthermore, the exhaust branch includes an electric regulating valve 2, a manual stop valve 3, a pressure gauge 4, a pressure sensor 5 and a gas nitrogen exhaust pipe 13 which are sequentially connected through pipelines along the airflow direction.

[0023] Furthermore, the circulating gas branch takes the test chamber 11 as the starting point and end point of the gas circulation, and includes an electric regulating valve 2, a manual stop valve 3, a pressure gauge 4, a temperature sensor 12, an electric heater 6 and a liquid nitrogen evaporator 16 connected in parallel through a pipeline along the airflow direction, as well as a circulating fan 15, a temperature sensor 12 and a pressure sensor 5; wherein, the electric heater 6 and the liquid nitrogen evaporator 16 are respectively provided with independent electric stop valves 7.

[0024] Furthermore, the liquid nitrogen injection branch includes a liquid nitrogen buffer tank 14, a manual stop valve 3, an electric regulating valve 2 and a pressure sensor 5 connected in sequence along the airflow direction through a pipeline; the liquid nitrogen discharge branch includes a manual stop valve 3, an electric regulating valve 2, a pressure sensor 5, a liquid nitrogen evaporator 16, a manual stop valve 3, an electric regulating valve 2 and a gas nitrogen discharge pipe 13 connected in sequence along the airflow direction through a pipeline.

[0025] The net size of the inner surface of the test chamber 11 of this embodiment is not less than 6.5m × 12.8m, and the material is 304LN stainless steel plate. The outer surface of the test chamber 11 and all structures, equipment and facilities on each branch that may be exposed to low temperatures are designed with insulation measures according to the minimum temperature of 77K. The cooling leakage of the insulation structure is not more than 60W / m 2 The fire protection grade of the insulation material is B2; the insulation material protective layer is wrapped with stainless steel with a thickness of more than 1mm.

[0026] Dry air buffer tank 9, for air replacement and pressure maintenance, with a working pressure of 0.8MPa, a dew point of -80℃, a CO2 content of 1ppm, and a volume greater than 100m 3 .

[0027] The nitrogen distribution station 10 is used for nitrogen replacement and pressure maintenance. The nitrogen working pressure at the outlet is 0.8 MPa, the dew point is -95°C, and the CO2 content is 0.1 ppm.

[0028] The liquid nitrogen evaporator 16 cools the air by evaporating the liquid nitrogen.

[0029] Electric heater 6 is used to reheat the air in test chamber 11 and the circulating gas branch. Its maximum power is 200 kW and is adjustable. When temperatures are low, it can be turned to maximum power to ensure a rapid heating rate. The heating rate can be controlled by adjusting the power of electric heater 6.

[0030] The air pressure regulating branch is used to achieve the required low pressure in the test chamber 11. To prevent the low-temperature gas and water vapor extracted from the test chamber 11 from damaging the vacuum pump unit 8, an electric heater 6 is installed at the inlet of the vacuum pump unit 8. The vacuum pump unit 8 adopts a two-stage vacuum pumping mode: a vacuum system and a high-vacuum system. The high-vacuum system uses multiple diffusion pumps as the pumping pump, of which a diffusion pump with a pumping speed of 30,000 L / s serves as the vacuum system's main pump.

[0031] The manual stop valve 3 configured at the outlet of the nitrogen distribution platform 10 and the liquid nitrogen buffer tank 14 is a low-temperature butterfly valve, and the electric regulating valve 2 is a low-temperature check valve; the material of the pipeline connecting the nitrogen distribution platform 10 and the liquid nitrogen buffer tank 14 is stainless steel with performance not lower than 304LN.

[0032] The test methods for the temperature and pressure environment test chamber of this embodiment include an air temperature and pressure environment test method and a nitrogen temperature and pressure environment test method; The air temperature and pressure environmental test method comprises the following steps: S11. Dry air buffer tank 9 introduces dry air into the test chamber 11. The volume of dry air buffer tank 9 is 100m 3 , dry air temperature 293K, pressure 0.5Mpa~0.8MPa, dew point -80℃, CO2 content 1ppm; after each dry air is introduced, let it stand for 3 minutes, wait for the dry and wet air to be fully mixed and exchanged, and then discharge it into the environment through the nitrogen exhaust pipe 13; after 20 cycles of replacement, check the dew point of the test chamber 11. If the dew point does not reach below -75℃, continue the replacement. If the dew point is below -75℃, end the replacement; S12. Liquid nitrogen buffer tank 14 has a capacity of 20m 3, the working pressure is 0.3Mpa~1.0Mpa, the liquid nitrogen buffer tank 14 discharges nitrogen to the gas nitrogen discharge pipe 13 through the liquid nitrogen evaporator 16, and the liquid nitrogen flow is adjusted by the electric regulating valve 2. After the liquid nitrogen evaporates, the dry air in the test chamber 11 is cooled; S13. The test chamber 11 realizes internal air flow through the circulating fan 15, and the fan air volume is 1000m 3 / h, the electric regulating valve 2 is used to adjust the liquid nitrogen flow rate of the liquid nitrogen buffer tank 14 and simultaneously control the cooling rate of the test chamber 11, and the cooling rate range is 50K / h~150K / h; when the temperature of the test chamber 11 is reduced from 293K to 110K, the cooling time is controlled to be more than 2 hours to avoid serious deformation of the test chamber 11 caused by excessive cooling. At the same time, the temperature is ensured to be no lower than 110K to avoid the danger of liquefaction of oxygen in the air; when the temperature of the test chamber 11 reaches the predetermined temperature of 110K, the liquid nitrogen flow rate is controlled to maintain the temperature of the test chamber 11 within a preset error range; S14. When the temperature of the test chamber 11 needs to be raised, the liquid nitrogen buffer tank 14 is closed, the electric heater 6 is turned on, and internal air circulation is achieved via the circulating fan 15. The heating rate is controlled by adjusting the power of the electric heater 6. When the temperature of the test chamber 11 reaches the predetermined temperature, the power of the electric heater 6 is controlled to maintain the temperature within a preset error range. It should be noted that when the temperature of the test chamber 11 is raised from 110K to 293K, the heating time is controlled to be no less than 3 hours, and the temperature rise is maintained steadily during the heating process. S15. When the test chamber 11 needs to increase the pressure, dry air is injected through the dry air buffer tank 9, the pressure of the pressure gauge 4 is monitored, and the amount of dry air introduced is controlled to ensure that the pressure is stable below 450Kpa and the pressure increase rate is maintained at 1Kpa / s; S16. The initial air is dry air at room temperature, and the temperature of the test chamber 11 is 273K~293K. It is required to reduce the pressure of the test chamber 11; if the real-time pressure of the test chamber 11 is greater than normal pressure, close the manual stop valve 3 and the electric stop valve 7 of the air inlet branch, open the electric regulating valve 2 and the manual stop valve 3 connected to the nitrogen exhaust pipe 13, and control the pressure reduction rate at 1KPa / s to ensure a stable pressure drop; if the real-time pressure of the test chamber 11 is less than normal pressure, close the manual stop valve 3 and the electric stop valve 7 of the air inlet branch, open the vacuum pump group 8 of the air pressure regulating branch, and extract air outward. When the pressure drops to 100Pa, the air extraction time is controlled within 2 hours. When the pressure drops to 1Pa, the air extraction time is controlled within 6 hours, and the pressure reduction rate is controlled at 1KPa / s to ensure a stable pressure drop; S17. The initial air is low-temperature air of 77K~273K, and the pressure of the test chamber 11 is required to be reduced; the pressure of the test chamber 11 is required to be reduced; if the real-time pressure of the test chamber 11 is greater than normal pressure, close the manual stop valve 3 and the electric stop valve 7 of the air intake branch, open the electric regulating valve 2 and the manual stop valve 3 connected to the nitrogen exhaust pipe 13, and control the pressure reduction rate to 1KPa / s; if the real-time pressure of the test chamber 11 is less than normal pressure, close the manual stop valve 3 and the electric stop valve 7 of the air intake branch, open the vacuum pump group 8 of the air pressure regulating branch, and turn on the electric heater 6 at the same time to extract air outward. When the pressure drops to 100Pa, the air extraction time is controlled within 2 hours. When the pressure drops to 1Pa, the air extraction time is controlled within 6 hours, and the pressure reduction rate is controlled at 1KPa / s to ensure a stable pressure drop; The nitrogen temperature and pressure environment test method comprises the following steps: S21. Dry nitrogen gas with a CO2 content of 0.1 ppm and a dew point of -95°C is introduced into the test chamber 11 via the nitrogen distribution station 10. The pressure of the dry nitrogen is adjusted to 0.8 MPa via the electric regulating valve 2. When the pressure in the test chamber 11 reaches 0.15 MPa, the nitrogen is allowed to stand for 3 to 5 minutes, then discharged to the environment through the nitrogen discharge pipe 13. This cycle of replacement is repeated at least 10 times until the nitrogen content in the test chamber 11 is greater than 99% and the dew point is below -90°C. S22. Liquid nitrogen buffer tank 14 sprays liquid nitrogen into test chamber 11. Circulating fan 15 provides nitrogen flow within test chamber 11. The rotating speed of circulating fan 15 is 100 rpm. The flow rate of liquid nitrogen from liquid nitrogen buffer tank 14 is regulated by electric regulating valve 2. The cooling rate is controlled at 50 K / h. When the temperature of test chamber 11 reaches the predetermined temperature range of 77 K to 293 K, the temperature is maintained within a preset error range. S23. When the temperature of the test chamber 11 needs to be increased, the liquid nitrogen buffer tank 14 is closed, the electric heater 6 is turned on, and the internal nitrogen flow is achieved through the circulating fan 15. The speed of the circulating fan 15 is 100 r / min; the power of the electric heater 6 is adjusted to 150 kW, and the heating rate is controlled to 50 K / h. When the temperature of the test chamber 11 reaches the predetermined temperature, the temperature is maintained within the preset error range. S24. When the pressure of the test chamber 11 needs to be increased, close the dry air buffer tank 9, open the nitrogen distribution station 10, and inject dry nitrogen into the test chamber 11. The dry nitrogen inlet pipe has a diameter of 10 mm and the exhaust pressure of the dry nitrogen is 0.8 MPa. By monitoring the pressure of the pressure gauge 4, the amount of dry nitrogen introduced is controlled to ensure that the pressure is stable within the preset range. S25. When the pressure of the test chamber 11 needs to be reduced, if the initial nitrogen is dry nitrogen at room temperature of 273K~293K, turn on the vacuum pump group 8 to extract nitrogen. When the pressure drops to 100Pa, the pumping time is controlled within 2 hours. When the pressure drops to 1Pa, the pumping time is controlled within 6 hours to ensure a stable pressure drop. S26. When the pressure of the test chamber 11 needs to be reduced, if the initial nitrogen is low-temperature nitrogen with a temperature of 77K~273K, close the manual stop valve 3 and the electric stop valve 7 of the nitrogen inlet branch, open the vacuum pump group 8 of the air pressure regulating branch, and turn on the electric heater 6 at the same time to heat the nitrogen to avoid damaging the vacuum pump group 8, and extract the nitrogen outward. When the pressure drops to 100Pa, the pumping time is controlled within 2 hours, and when the pressure drops to 1Pa, the pumping time is controlled within 6 hours to ensure a stable pressure drop.

Claims

1. A temperature and pressure environment test chamber, characterized in that: The main body of the temperature and pressure environment test chamber is a test chamber body (11), and the test chamber body (11) is externally connected to an air intake branch, an air pressure regulating branch, an exhaust branch, a circulating gas branch, and a liquid nitrogen injection branch; the air intake branch is used to transport gas to the test chamber body (11); the air pressure regulating branch is used to regulate the pressure of the air intake branch; the exhaust branch is used to discharge the gas in the test chamber body (11); the circulating gas branch is used to circulate the gas in the test chamber body (11); the liquid nitrogen injection branch includes a liquid nitrogen injection branch and a liquid nitrogen discharge branch, the liquid nitrogen injection branch is used to inject liquid nitrogen into the test chamber body (11), and the liquid nitrogen discharge branch is used to discharge nitrogen from the liquid nitrogen buffer tank (14).

2. The temperature and pressure environment test chamber according to claim 1, characterized in that: The air intake branch comprises an air intake branch and a nitrogen intake branch connected in parallel; the air intake branch comprises a dry air buffer tank (9), a manual stop valve (3) and an electric stop valve (7) connected in sequence through a pipeline in the direction of air flow, and the nitrogen intake branch comprises a dry air buffer tank (9), a manual stop valve (3) and an electric stop valve (7) connected in sequence through a pipeline in the direction of air flow; thereafter, the air intake branch and the nitrogen intake branch are combined into an intake pipeline connected to a test chamber (11), and the intake pipeline comprises a filter (1), a pressure sensor (5), a pressure gauge (4), an electric regulating valve (2), a manual stop valve (3), a pressure gauge (4) and a pressure sensor (5) connected in sequence through a pipeline in the direction of air flow.

3. The temperature and pressure environment test chamber according to claim 2, characterized in that: The starting point of the air pressure regulating branch is connected to the manual stop valve (3) of the air inlet pipe; the air pressure regulating branch comprises a manual stop valve (3), a pressure gauge (4), a pressure sensor (5), an electric heater (6), an electric stop valve (7), a manual stop valve (3) and a vacuum pump group (8) which are sequentially connected through a pipe along the air flow direction; a filter (1) which is connected to the atmosphere in parallel through an electric regulating valve (2) is connected behind the pressure gauge (4) of the air pressure regulating branch; the vacuum pump group (8) adopts a two-stage vacuum pumping mode of a vacuum system and a high vacuum system.

4. The temperature and pressure environment test chamber according to claim 3, characterized in that: The exhaust branch comprises an electric regulating valve (2), a manual stop valve (3), a pressure gauge (4), a pressure sensor (5) and a gas nitrogen exhaust pipe (13) which are sequentially connected through a pipeline along the airflow direction.

5. The temperature and pressure environment test chamber according to claim 4, characterized in that: The circulating gas branch takes the test chamber (11) as the starting point and end point of the gas circulation, and includes an electric regulating valve (2), a manual stop valve (3), a pressure gauge (4), a temperature sensor (12), an electric heater (6) and a liquid nitrogen evaporator (16) connected in parallel through a pipeline along the airflow direction, as well as a circulating fan (15), a temperature sensor (12) and a pressure sensor (5); wherein, the electric heater (6) and the liquid nitrogen evaporator (16) are respectively provided with independent electric stop valves (7).

6. The temperature and pressure environment test chamber according to claim 5, characterized in that: The liquid nitrogen injection branch comprises a liquid nitrogen buffer tank (14), a manual stop valve (3), an electric regulating valve (2), and a pressure sensor (5) which are sequentially connected through a pipeline in the direction of the gas flow; and the liquid nitrogen discharge branch comprises a manual stop valve (3), an electric regulating valve (2), a pressure sensor (5), a liquid nitrogen evaporator (16), a manual stop valve (3), an electric regulating valve (2), and a gas nitrogen discharge pipe (13) which are sequentially connected through a pipeline in the direction of the gas flow.

7. A test method for a temperature and pressure environment test chamber, used in the temperature and pressure environment test chamber according to claim 6, characterized in that: The test methods include air temperature and pressure environment test methods and nitrogen temperature and pressure environment test methods; The air temperature and pressure environmental test method comprises the following steps: S11. Dry air is introduced into the test chamber (11) from the dry air buffer tank (9), and after standing and exchanging, the dry air is discharged into the environment through the nitrogen discharge pipe (13); a total of more than 20 cycles of replacement are performed until the dew point of the test chamber (11) is lower than -75°C; S12. The liquid nitrogen buffer tank (14) discharges nitrogen gas to the nitrogen gas discharge pipe (13) through the liquid nitrogen evaporator (16), thereby evaporating the liquid nitrogen and cooling the dry air in the test chamber (11); S13. The test chamber (11) is provided with a circulating fan (15) to realize internal air flow, and the electric regulating valve (2) is used to adjust the liquid nitrogen flow rate of the liquid nitrogen buffer tank (14) while controlling the cooling rate of the test chamber (11). When the temperature of the test chamber (11) reaches a predetermined temperature, the temperature is maintained within a preset error range; S14. When the temperature of the test chamber (11) needs to be increased, the liquid nitrogen buffer tank (14) is closed, the electric heater (6) is turned on, and internal air flow is achieved through the circulating fan (15). The heating rate is controlled by adjusting the power of the electric heater (6). When the temperature of the test chamber (11) reaches the predetermined temperature, the temperature is maintained within a preset error range. S15. When the pressure of the test chamber (11) needs to be increased, dry air is injected through the dry air buffer tank (9), the pressure of the pressure gauge (4) is monitored, and the amount of dry air introduced is controlled to ensure that the pressure is stable within the preset range; S16. The initial air is dry air at room temperature of 273K~293K, and the pressure of the test chamber (11) is required to be reduced; if the real-time pressure of the test chamber (11) is greater than the normal pressure, close the manual stop valve (3) and the electric stop valve (7) of the air inlet branch, open the electric regulating valve (2) and the manual stop valve (3) connected to the nitrogen exhaust pipe (13), and ensure that the pressure decreases according to the preset pressure reduction rate; if the pressure is less than the normal pressure, close the manual stop valve (3) and the electric stop valve (7) of the air inlet branch, open the vacuum pump group (8) of the air pressure regulating branch, and extract air to the outside to ensure that the pressure decreases according to the preset pressure reduction rate; S17. The initial air is low-temperature air of 77K~273K, and the pressure of the test chamber (11) is required to be reduced; if the real-time pressure of the test chamber (11) is greater than the normal pressure, close the manual stop valve (3) and the electric stop valve (7) of the air inlet branch, open the electric regulating valve (2) and the manual stop valve (3) connected to the nitrogen exhaust pipe (13), and ensure that the pressure decreases according to the pre-set pressure reduction rate; if the real-time pressure of the test chamber (11) is less than the normal pressure, close the manual stop valve (3) and the electric stop valve (7) of the air inlet branch, open the vacuum pump group (8) of the air pressure regulating branch, and at the same time turn on the electric heater (6) to draw air outward to ensure that the pressure decreases according to the pre-set pressure reduction rate; The nitrogen temperature and pressure environment test method comprises the following steps: S21. Dry nitrogen is introduced into the test chamber (11) through the nitrogen distribution table (10). After standing for exchange, the nitrogen is discharged into the environment through the nitrogen discharge pipe (13). The nitrogen content in the test chamber (11) is greater than 99% and the dew point is lower than -90°C after more than 10 cycles of exchange. S22. The liquid nitrogen buffer tank (14) sprays liquid nitrogen into the test chamber (11). The test chamber (11) realizes internal nitrogen flow through the circulating fan (15). The liquid nitrogen flow of the liquid nitrogen buffer tank (14) is adjusted by the electric regulating valve (2) to control the cooling rate. When the temperature of the test chamber (11) reaches the predetermined temperature range of 77K~293K, the temperature is maintained within the preset error range. S23. When the temperature of the test chamber (11) needs to be increased, the liquid nitrogen buffer tank (14) is closed, the electric heater (6) is turned on, and the internal nitrogen flow is realized through the circulating fan (15). The heating rate is controlled by adjusting the power of the electric heater (6). When the temperature of the test chamber (11) reaches the predetermined temperature, the temperature is maintained within a preset error range; S24. When the pressure of the test chamber (11) needs to be increased, the dry air buffer tank (9) is closed, the nitrogen distribution station (10) is opened, and dry nitrogen is injected into the test chamber (11). By monitoring the pressure of the pressure gauge (4), the amount of dry nitrogen introduced is controlled to ensure that the pressure is stable within the preset range; S25. When the pressure of the test chamber (11) needs to be reduced, if the initial nitrogen is dry nitrogen at room temperature of 273K~293K, turn on the vacuum pump group (8) to pump nitrogen out to ensure that the pressure decreases according to the pre-set pressure reduction rate; S26. When the pressure of the test chamber (11) needs to be reduced, if the initial nitrogen is low-temperature nitrogen at 77K~273K, close the manual stop valve (3) and the electric stop valve (7) of the nitrogen inlet branch, open the vacuum pump group (8) of the pressure regulating branch, and at the same time turn on the electric heater (6) to heat the nitrogen to avoid damaging the vacuum pump group (8), and draw nitrogen out to ensure that the pressure drops according to the pre-set pressure reduction rate.

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