Precise temperature control method for vacuum optical equipment and equipment thereof

Abstract

The invention provides a precise temperature control method and device for vacuum optical equipment, the precise temperature control device comprises a mechanical refrigeration unit, a gas nitrogen circulation unit and a heat exchange unit, the mechanical refrigeration unit comprises a compressor and a refrigerant circulation pipeline and is used for generating cooling capacity; the gas nitrogen circulating unit comprises a gas nitrogen fan, a gas nitrogen circulating pipeline and a temperature control bottom plate arranged in the vacuum cabin, and is used for transferring cold energy into the vacuum cabin; and a heat-conducting medium is arranged in the heat exchange unit and is used for indirectly transferring the cold energy generated by the refrigeration unit to the gas nitrogen circulating unit. The technical problems that when high and low temperature tests are carried out on existing optical equipment in a vacuum environment, high temperature control precision cannot be considered at the same time, and optical elements cannot be polluted after refrigerant leakage are solved. The device and the method can be widely applied to optical element testing in a vacuum environment.

Description

Technical Field

[0001] This invention relates to the field of temperature control, and in particular to a precision temperature control method and apparatus for vacuum optical equipment. Background Technology

[0002] In existing technologies, internal cooling in thermal vacuum equipment typically uses liquid nitrogen or mechanical refrigeration units. However, vacuum optical equipment requires high precision in temperature control, and it is also crucial that any accidental leakage of the cooling medium from the cold plates or pipes within the vacuum chamber does not contaminate the optical mirrors. Liquid nitrogen pipes, when leaking, turn into nitrogen gas, which does not contaminate the optical mirrors, and therefore are often the preferred choice for cooling. However, using liquid nitrogen solely for temperature control presents challenges in adjustment and large temperature control deviations, making it difficult to meet the high-precision testing requirements of optical equipment in a vacuum environment.

[0003] On the other hand, although traditional mechanical refrigeration units have high temperature control accuracy, if their refrigerant leaks inside the vacuum chamber, it will evaporate or adhere to the optical mirror surface, causing serious pollution or even rendering the optical components unusable, posing a high risk of use.

[0004] To address the aforementioned issues, some improvements have been proposed in existing technologies. For example, Chinese patent application CN113566441A discloses a large-scale high and low temperature environment simulation test system with dual cold sources. This system uses a mechanical refrigeration unit and a liquid nitrogen supply system as dual cold sources. Liquid nitrogen is vaporized into gaseous nitrogen through a gaseous nitrogen generation and pressure stabilization system, which, together with the refrigeration system, provides a cold source for the insulated chamber. The main purpose of this solution is to improve the system's redundancy; when one cold source fails, the other can continue to operate, representing a parallel disaster recovery approach. Although this solution achieves a dual configuration of cold sources, its essence remains a simple parallel connection of cold sources. The mechanical refrigeration and gaseous nitrogen refrigeration are relatively independent, failing to solve the core technical problem of simultaneously addressing the requirements of high-precision temperature control and high cleanliness in the specific application scenario of vacuum optical equipment. Summary of the Invention

[0005] This invention addresses the technical problem that existing optical equipment cannot simultaneously achieve high temperature control accuracy and prevent refrigerant leakage from contaminating optical components when conducting high and low temperature tests in a vacuum environment. It provides a precision temperature control method and equipment for vacuum optical equipment that has high temperature control accuracy and prevents refrigerant from damaging optical components in the event of pipeline leakage.

[0006] Therefore, the technical solution of the present invention is a precision temperature control device for vacuum optical equipment, comprising a mechanical refrigeration unit, a gas-nitrogen circulation unit, and a heat exchange unit. The mechanical refrigeration unit includes a compressor and a refrigerant circulation pipeline for generating cooling capacity. The gas-nitrogen circulation unit includes a gas-nitrogen fan, a gas-nitrogen circulation pipeline, and a temperature control base plate disposed within the vacuum chamber for transferring cooling capacity into the vacuum chamber. The heat exchange unit contains a heat-conducting medium for indirectly transferring the cooling capacity generated by the refrigeration unit to the gas-nitrogen circulation unit.

[0007] Preferably, the heat exchange unit adopts a closed oil tank, the heat transfer medium is silicone oil, and the space above the silicone oil surface in the closed oil tank is filled with nitrogen.

[0008] Preferably, the enclosed oil tank is provided with a refrigeration coil connected to the refrigerant circulation pipeline and a gas nitrogen circulation coil connected to the gas nitrogen circulation pipeline, and the refrigeration coil and the gas nitrogen circulation coil exchange heat through the heat transfer medium.

[0009] Preferably, the refrigerant circulation pipeline of the mechanical refrigeration unit is equipped with a hot bypass valve, a cold bypass valve, and a refrigeration expansion valve to regulate the refrigerant flow rate entering the refrigeration coil.

[0010] Preferably, a heater is installed on the gas nitrogen circulation pipeline between the closed oil tank and the vacuum chamber.

[0011] Preferably, the gas-nitrogen circulation pipeline is equipped with a gas replenishment valve and a vent valve. The gas replenishment valve is connected to the gas-nitrogen source, and the gas replenishment valve and the vent valve are used to regulate the pressure in the gas-nitrogen circulation pipeline.

[0012] A precision temperature control method for vacuum optical equipment includes the following steps: S1: Cooling capacity generation: Cooling capacity is generated by the compressor of the mechanical refrigeration unit. The refrigerant enters the refrigeration coil through the refrigeration expansion valve. The refrigerant evaporates and absorbs heat in the closed oil tank containing the heat transfer medium, thereby reducing the temperature of the heat transfer medium. S2: Cooling transfer: The gas nitrogen fan drives the nitrogen to flow through the gas nitrogen circulation coil, where it exchanges heat with the heat transfer medium in the closed oil tank to reduce the temperature of the nitrogen. S3: Temperature control execution: Low-temperature nitrogen gas flows through the gas nitrogen circulation pipeline into the vacuum chamber, cooling the temperature control base plate and achieving temperature control in a vacuum environment.

[0013] Preferably, precise temperature control methods are also included: The amount of cold air entering the refrigeration coil is controlled by adjusting the hot bypass valve, cold bypass valve, and refrigeration expansion valve. At the same time, the heater on the gas-nitrogen circulation pipeline is controlled to perform fine compensation heating of the nitrogen gas that has undergone heat exchange with the heat transfer medium. Through the combination of coarse adjustment of cold air and fine adjustment of heating, the temperature control base plate can be precisely adjusted.

[0014] Preferably, safety monitoring methods are also included: The vacuum level inside the vacuum chamber is monitored in real time by installing a vacuum measuring gauge on the vacuum chamber. The pressure and temperature in the gas nitrogen circulation pipeline are monitored by a pressure and temperature measuring device at the inlet of the gas nitrogen pipeline. When the pressure exceeds the set value, the pressure is released through the vent valve; when the pressure is lower than the set value, nitrogen is replenished from the gas nitrogen source through the gas replenishment valve.

[0015] The beneficial effects of this invention are: (1) This application uses a mechanical refrigeration unit and a gas nitrogen circulation unit together to transfer the cooling capacity of the mechanical refrigeration unit to the gas nitrogen circulation unit through a heat transfer medium. The gas nitrogen circulation unit is connected to the vacuum chamber and adjusts the temperature of the temperature control base plate in the vacuum chamber. The temperature of the mechanical refrigeration unit can be precisely adjusted. Even if the gas nitrogen leaks in the vacuum chamber, it will not contaminate the optical components. This solves the technical problem in the prior art that the temperature adjustment accuracy and the cleanliness of the circulation medium in the vacuum chamber cannot be taken into account at the same time. (2) Silicone oil is used as the heat transfer medium. The silicone oil is located in a closed oil tank. Nitrogen is filled above the surface of the silicone oil to isolate it from the air. The operating temperature of silicone oil is -85℃ to 180℃. It has good fluidity at low temperatures and does not frost. It has stable performance as a heat transfer medium and can ensure the long-term stable operation of the system. Silicone oil has good thermal conductivity and can quickly realize the heat exchange between the refrigerant and gaseous nitrogen. (3) The supply of cold energy is controlled by the hot bypass valve and cold bypass valve of the mechanical refrigeration unit, and a small amount of heating is carried out by the heater on the gas nitrogen circulation pipeline. The two are used together to achieve high-precision temperature regulation in the vacuum chamber. (4) In this application, the gaseous nitrogen source can be obtained by vaporizing liquid nitrogen or by directly using a nitrogen cylinder. It does not require complicated auxiliary equipment, adapts to different laboratory conditions, and has the advantages of good economy, compact structure and small footprint. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the principle structure of an embodiment of the present invention.

[0017] Explanation of symbols in the diagram: 1. Refrigeration compressor; 2. Water-cooled plate heat exchanger; 3. Hot bypass valve; 4. Cold bypass valve; 5. Refrigeration expansion valve; 6. Heat exchange oil tank; 7. Oil level measuring device; 8. Oil temperature sensor; 9. Heat exchange oil tank pressure sensor; 10. Safety valve; 11. Heat exchange oil tank pressure relief valve; 12. Heater; 13. Inlet pressure and temperature measuring device for gaseous and nitrogen pipeline; 14. Vacuum chamber; 15. Temperature control base plate; 16. Vacuum measuring gauge; 17. Gaseous and nitrogen pipeline vent valve; 18. Gaseous and nitrogen fan; 19. Gaseous and nitrogen pipeline make-up valve; 20. Liquid nitrogen vaporizer; 21. Liquid nitrogen pipeline; 22. Refrigeration coil; 23. Gaseous and nitrogen circulation coil. Detailed Implementation

[0018] The present invention will be further described below with reference to embodiments.

[0019] like Figure 1 As shown, this invention provides a precision temperature control device for vacuum optical equipment, mainly comprising a mechanical refrigeration unit, a gas-nitrogen circulation unit, and a heat exchange oil tank 6 as the core of cold energy exchange. The mechanical refrigeration unit mainly consists of a refrigeration compressor 1, a water-cooled plate heat exchanger 2, a heat bypass valve 3, a cold bypass valve 4, a refrigeration expansion valve 5, a refrigeration coil 22, and related piping. Driven by the compressor 1, the refrigerant circulates and, after being throttled by the refrigeration expansion valve 5, flows into the refrigeration coil 22 located in the heat exchange oil tank 6. The refrigerant evaporates and absorbs heat, lowering the temperature of the heat-conducting medium in the heat exchange oil tank 6. The gas-nitrogen circulation unit mainly consists of a gas-nitrogen fan 18, a gas-nitrogen circulation coil 23, a heater 12, a temperature control base plate 15 in the vacuum chamber 14 for placing the optical components to be tested, and related piping. The gas-nitrogen fan 18 drives gas-nitrogen to flow in a closed pipeline. When the gas-nitrogen flows through the gas-nitrogen circulation coil 23 in the heat exchange oil tank 6, it exchanges heat with the low-temperature heat-conducting medium, becoming low-temperature nitrogen gas. The low-temperature nitrogen then flows into the vacuum chamber 14 through the pipeline, cooling the temperature control base plate 15. After absorbing heat, the nitrogen returns to the nitrogen blower 18 for the next cycle.

[0020] The heat exchange oil tank 6, serving as the heat transfer component of this invention, adopts a closed structure. In this embodiment, the preferred heat transfer medium is silicone oil with a temperature range of -85℃ to 180℃, good low-temperature fluidity, and low volatility. The refrigeration coil 22 of the mechanical refrigeration unit and the gas nitrogen circulation coil 23 of the gas nitrogen circulation unit are immersed in the silicone oil. The two sets of coils exist independently and exchange heat with the silicone oil separately. That is, the cooling capacity of the mechanical refrigeration unit is transferred to the silicone oil, and the silicone oil transfers its cooling capacity to the gas nitrogen circulation unit, completing the indirect heat exchange between the two media. To prevent moisture in the air from entering the heat exchange oil tank 6 and causing freezing or frost, the remaining space above the silicone oil surface in the heat exchange oil tank 6 is filled with nitrogen for protection, and the exterior of the heat exchange oil tank 6 is covered with insulation cotton to reduce cooling loss.

[0021] In addition, the heat exchange oil tank 6 is also equipped with an oil level measuring device 7 for monitoring the oil level, an oil temperature sensor 8 for monitoring the oil temperature, a heat exchange oil tank pressure sensor 9 for monitoring the internal pressure, as well as a safety valve 10 to prevent overpressure and a heat exchange oil tank pressure relief valve 11, to ensure the safe operation of the equipment.

[0022] To improve temperature control accuracy, a hot bypass valve 3 and a cold bypass valve 4 are installed on the piping of the mechanical refrigeration unit. The control system can precisely control the amount of cooling entering the refrigeration coil 22 by adjusting the switching frequency of the hot bypass valve 3, the cold bypass valve 4, and the refrigeration expansion valve 5. At the same time, a heater 12 is installed on the nitrogen circulation pipeline between the outlet of the heat exchange oil tank 6 and the inlet of the vacuum chamber 14, which can provide a small amount of heating to the nitrogen. Through this combination of "coarse adjustment (mechanical refrigeration) + fine adjustment (electric heating)," the temperature of the nitrogen entering the vacuum chamber 14 can be precisely controlled, thereby ensuring that the temperature control base plate 15 is stably maintained at a high-precision target temperature.

[0023] The gas-nitrogen circulation unit is connected to an external nitrogen source, which is accessed through the gas-nitrogen pipeline makeup valve 19. The nitrogen source can be obtained by vaporizing liquid nitrogen through the liquid nitrogen pipeline 21 via the liquid nitrogen vaporizer 20, or it can be directly connected to an external high-purity nitrogen cylinder. This eliminates the need for complex auxiliary equipment, adapting to different laboratory conditions and offering advantages such as good economy, compact structure, and small footprint. By controlling the opening and closing of the gas-nitrogen pipeline makeup valve 19, the nitrogen pressure within the gas-nitrogen circulation pipeline is adjusted in real time. When the pressure is too high, some nitrogen can be discharged through the gas-nitrogen pipeline vent valve 17 to maintain normal pressure. The gas-nitrogen pipeline inlet pressure and temperature measuring device 13 monitors the nitrogen status before it enters the vacuum chamber 14 in real time, providing feedback for system regulation. Nitrogen remains a gas at temperatures above -196℃, and therefore remains a gas throughout its flow in the gas-nitrogen circulation pipeline.

[0024] The present invention also provides a precision temperature control method for vacuum optical equipment, comprising the following steps: S1: Cooling capacity generation: Cooling capacity is generated by the compressor 1 of the mechanical refrigeration unit. The refrigerant enters the refrigeration coil 22 through the refrigeration expansion valve 5 and evaporates and absorbs heat in the heat exchange oil tank 6 containing the heat transfer medium, thereby reducing the temperature of the heat transfer medium. S2: Cold transfer: The gas nitrogen fan 18 drives the nitrogen to flow through the gas nitrogen circulation coil 23, and exchange heat with the heat transfer medium in the heat exchange oil tank 6 to reduce the temperature of the nitrogen. S3: Temperature control execution: Low-temperature nitrogen gas flows into the vacuum chamber 14 through the nitrogen gas circulation pipeline, cooling the temperature control base plate 15 and realizing temperature control in a vacuum environment.

[0025] It also includes precise temperature control methods: The amount of cold air entering the refrigeration coil 22 is controlled by adjusting the hot bypass valve 3, the cold bypass valve 4 and the refrigeration expansion valve 5; at the same time, the heater 12 on the gas-nitrogen circulation pipeline is controlled to perform fine compensation heating of the nitrogen gas that has undergone heat exchange with the heat transfer medium. Through the combination of coarse adjustment of cold air and fine adjustment of heating, the temperature control base plate 15 can be accurately and efficiently regulated.

[0026] It also includes safety monitoring methods: The vacuum level inside the vacuum chamber 14 is monitored in real time by installing a vacuum measuring gauge 16 on the vacuum chamber 14; the pressure and temperature values ​​in the gas nitrogen circulation pipeline are monitored by the gas nitrogen pipeline inlet pressure and temperature measuring device 13; when the pressure exceeds the set value, the pressure is released through the vent valve 17; when the pressure is lower than the set value, nitrogen is replenished from the gas nitrogen source through the gas replenishment valve 19.

[0027] This application uses a mechanical refrigeration unit and a gas-nitrogen circulation unit in combination. The cooling capacity of the mechanical refrigeration unit is transferred to the gas-nitrogen circulation unit through a heat transfer medium. The gas-nitrogen circulation unit is connected to the vacuum chamber 14 and adjusts the temperature of the temperature control base plate 15 inside the vacuum chamber 14. The temperature of the mechanical refrigeration unit can be precisely adjusted. Even if gas-nitrogen leaks inside the vacuum chamber 14, it will not contaminate the optical components. This solves the technical problem in the prior art that it is impossible to balance the temperature control accuracy and cleanliness inside the vacuum chamber 14.

[0028] However, the above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A precision temperature control device for vacuum optical equipment, characterized in that, It includes a mechanical refrigeration unit, a gas-nitrogen circulation unit, and a heat exchange unit. The mechanical refrigeration unit includes a compressor and a refrigerant circulation pipeline for generating cooling capacity. The gas-nitrogen circulation unit includes a gas-nitrogen fan, a gas-nitrogen circulation pipeline, and a temperature control base plate installed inside the vacuum chamber for transferring cooling capacity into the vacuum chamber. The heat exchange unit contains a heat-conducting medium for indirectly transferring the cooling capacity generated by the refrigeration unit to the gas-nitrogen circulation unit.

2. The precision temperature control device for vacuum optical equipment according to claim 1, characterized in that, The heat exchange unit adopts a closed oil tank, the heat transfer medium is silicone oil, and the space above the silicone oil surface in the closed oil tank is filled with nitrogen.

3. The precision temperature control device for vacuum optical equipment according to claim 2, characterized in that, The enclosed oil tank is equipped with a refrigeration coil connected to the refrigerant circulation pipeline and a gas nitrogen circulation coil connected to the gas nitrogen circulation pipeline. The refrigeration coil and the gas nitrogen circulation coil exchange heat through the heat transfer medium.

4. The precision temperature control device for vacuum optical equipment according to claim 1, characterized in that, The refrigerant circulation pipeline of the mechanical refrigeration unit is equipped with a hot bypass valve, a cold bypass valve, and a refrigeration expansion valve to regulate the refrigerant flow rate into the refrigeration coil.

5. The precision temperature control device for vacuum optical equipment according to claim 2, characterized in that, A heater is installed on the gas nitrogen circulation pipeline between the closed oil tank and the vacuum chamber.

6. The precision temperature control device for vacuum optical equipment according to claim 1, characterized in that, The gas-nitrogen circulation pipeline is equipped with a gas replenishment valve and a vent valve. The gas replenishment valve is connected to the gas-nitrogen source, and the gas replenishment valve and the vent valve are used to regulate the pressure in the gas-nitrogen circulation pipeline.

7. A precision temperature control method for vacuum optical equipment using the apparatus described in claims 1-6, characterized in that, Includes the following steps: S1: Cooling capacity generation: Cooling capacity is generated by the compressor of the mechanical refrigeration unit. The refrigerant enters the refrigeration coil through the refrigeration expansion valve. The refrigerant evaporates and absorbs heat in the closed oil tank containing the heat transfer medium, thereby reducing the temperature of the heat transfer medium. S2: Cooling transfer: The nitrogen fan drives the nitrogen to flow through the nitrogen circulation coil, where it exchanges heat with the heat-conducting medium in the closed oil tank, thereby reducing the temperature of the nitrogen. S3: Temperature control execution: Low-temperature nitrogen gas flows through the gas nitrogen circulation pipeline into the vacuum chamber, cooling the temperature control base plate and achieving temperature control in a vacuum environment.

8. The precision temperature control method for vacuum optical equipment according to claim 7, characterized in that, It also includes precise temperature control methods: The amount of cold air entering the refrigeration coil is controlled by adjusting the hot bypass valve, cold bypass valve, and refrigeration expansion valve. At the same time, the heater on the gas-nitrogen circulation pipeline is controlled to perform fine compensation heating of the nitrogen gas that has undergone heat exchange with the heat transfer medium. Through the combination of coarse adjustment of cold air and fine adjustment of heating, the temperature control base plate can be precisely adjusted.

9. The precision temperature control method for vacuum optical equipment according to claim 7, characterized in that, It also includes safety monitoring methods: The vacuum level inside the vacuum chamber is monitored in real time by installing a vacuum measuring gauge on the vacuum chamber. The pressure and temperature in the gas nitrogen circulation pipeline are monitored by a pressure and temperature measuring device at the inlet of the gas nitrogen pipeline. When the pressure exceeds the set value, the pressure is released through the vent valve; when the pressure is lower than the set value, nitrogen is replenished from the gas nitrogen source through the gas replenishment valve.

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