Gas replacement system for stable detection of ozone radar

Abstract

The invention discloses a gas replacement system for stable detection of an ozone radar, and belongs to the technical field of laser radars. According to the system, a dual-mode gas circulation framework is adopted and comprises a main channel internal circulation mode and an auxiliary channel external circulation mode, the purity of gas in the laser is ensured through a multi-stage filtering device, a core optical element is protected, and stable laser output performance is maintained. Wherein the main channel is used for maintaining the basic gas replacement flow, and the auxiliary channel is automatically switched to an external circulation mode when detecting that the laser power is abnormal, so that regular and quantitative gas replacement is realized, and the emergency treatment capacity of the system on pollutants is remarkably improved. Besides, the system innovatively adopts a light-gas-heat coupling design, and the problems of optical window condensation and temperature fluctuation in an extremely low temperature environment are effectively solved through a laser temperature control and ozone radar gas circulation integrated structure, a self-cleaning film layer and a phase change material heat storage technology; and the detection stability, precision and reliability of the ozone radar are obviously improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser radar, and in particular relates to a gas replacement system for stable detection of ozone radar. Background Art

[0002] Ozone lidar (especially differential absorption lidar, DIAL) is the core equipment for detecting the vertical distribution of atmospheric ozone. It emits two laser beams of specific wavelengths (absorption wavelength Non-absorption wavelength ), using the differential absorption characteristics of ozone molecules to invert concentration. However, the power stability of the laser directly affects the radar's detection performance, including signal-to-noise ratio, detection altitude, data accuracy, and long-term reliability.

[0003] The main factors affecting the stability of laser power include power attenuation caused by optical cavity contamination: key components such as lenses and crystals in the laser optical cavity are exposed to the air for a long time, and water vapor, dust and ozone photochemical residues will adhere to the surface, increasing optical path loss and causing the laser power to continue to decline; temperature fluctuations cause optical component offset: temperature changes will cause optical components to expand and contract, reduce coupling efficiency, and affect the echo signal intensity and signal-to-noise ratio; power fluctuations destroy inversion accuracy: laser power decreases or fluctuations will distort the differential absorption contrast, resulting in ozone concentration inversion errors (typical deviation >10%), especially in low-concentration high-altitude areas.

[0004] Traditional protective measures have many limitations. Static sealing can only delay contamination but cannot remove intruding impurities. After long-term operation, it still needs to be disassembled and cleaned, resulting in frequent shutdowns for maintenance. Passive dehumidification devices use desiccants such as silica gel or molecular sieves, which need to be replaced regularly. The maintenance cost is high, and they cannot completely prevent the deposition of particulate matter or chemical pollutants, making it difficult to deal with the risk of condensation in high humidity environments. Although passive heat dissipation design can reduce laser temperature and thermally induced power fluctuations, it still cannot solve the problem of nonlinear power attenuation caused by optical contamination.

[0005] To maintain detection performance, existing ozone radars often sacrifice efficiency (e.g., increasing integration time and reducing resolution) or add hardware redundancy (e.g., backup lasers), significantly increasing system cost and complexity. Therefore, a proactive and sustainable pollution control solution is urgently needed to fundamentally ensure laser power stability and improve ozone radar detection reliability and accuracy. Summary of the Invention

[0006] To address the aforementioned technical issues, the present invention provides a gas replacement system for stable ozone radar detection. This system utilizes a dual-mode gas circulation system (using a primary / secondary dual-circulation channel design), a coupled optical-gas-thermal design, and coordinated control of multiple parameters, including airflow and humidity. Firstly, the dual-mode gas circulation system employs a multi-stage filtration unit to ensure the purity of the gas within the laser, protecting the laser's core optical components and maintaining stable laser output performance. The primary channel (internal circulation) maintains a baseline gas replacement flow rate of 1-5 L / min, while the secondary channel (external circulation) activates external circulation mode upon detecting power anomalies, achieving timed and quantitative gas replacement. Compared to traditional single-channel designs, this system improves laser contamination emergency response capabilities and ensures laser power stability. Secondly, the optical window is coated with a self-cleaning coating (anti-reflection coating + hydrophobic coating + wear-resistant protective layer) to effectively reduce the adhesion of ice crystals in low-temperature environments. The heat sink integrates laser temperature control and ozone radar gas circulation, combining both functions. The flow channel structure serves as both the laser's core heat sink and the main circulation channel of the gas displacement system. In extremely low-temperature environments (-40°C), this solution effectively addresses optical window condensation and temperature fluctuations by integrating the ozone radar's gas circulation and laser temperature control, utilizing a self-cleaning membrane, a PTC heating film, and heat sink phase-change material heat storage technology. Compared to traditional electric heating solutions, this solution reduces energy consumption by 70%, maintains temperature fluctuations to less than ±0.5°C, and maintains stable system operation in environments ranging from -40°C to +60°C. Furthermore, the dynamic gas displacement system utilizes a coordinated control scheme for multiple parameters, including airflow and humidity. The system intelligently adjusts airflow rate and automatically switches to external circulation mode when power fluctuations exceeding 2% are detected, effectively preventing significant laser power loss and differential absorption signal distortion. When optical cavity humidity exceeds 40%, the system automatically switches to internal circulation mode, increasing the main channel flow rate by 50% to significantly suppress condensation. This significantly improves the detection stability, accuracy, and reliability of the ozone radar.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A gas replacement system for stable ozone radar detection includes a dual-mode gas circulation architecture and a thermal coupling architecture, wherein:

[0009] The dual-mode gas circulation architecture includes a main channel and an auxiliary channel. The main channel is used to maintain the basic gas replacement flow rate in the laser optical cavity to achieve an internal circulation mode. The auxiliary channel automatically switches to an external circulation mode when abnormal laser power is detected to achieve timed and quantitative gas replacement.

[0010] The thermal coupling structure is used to dissipate the heat generated by the laser to the external environment, and to preheat the gas in an internal circulation mode before entering the laser optical cavity.

[0011] Furthermore, the system also includes a first solenoid valve, a second solenoid valve, and a third solenoid valve, wherein the first solenoid valve is used to control the opening and closing of the internal circulation, the second solenoid valve is used to control the automatic switching between the internal circulation and the external circulation, and the third solenoid valve is used to control the opening and closing of the external circulation.

[0012] Furthermore, the thermal coupling structure includes a temperature-controlled uniform heat plate, a heat sink, and a fan stacked in sequence below the laser.

[0013] Furthermore, when the third solenoid valve is closed, the second solenoid valve automatically switches to the internal circulation mode. The gas at the radiator outlet enters the first multi-stage filtration unit through the first solenoid valve, flows into the laser optical cavity through the laser air inlet, and flows out through the laser air outlet. The outflowing gas passes through the diaphragm pump and the second solenoid valve in turn and flows into the radiator air inlet, forming an internal circulation system.

[0014] Furthermore, when the first solenoid valve is closed, the second solenoid valve automatically switches to the external circulation mode, and the third solenoid valve opens. The gas in the external environment enters the first multi-stage filtration unit through the third solenoid valve, flows into the laser optical cavity through the laser air inlet, and flows out through the laser air outlet. The outflowing gas passes through the diaphragm pump, the second solenoid valve, and the second multi-stage filtration unit in sequence and is discharged to the external environment, forming an external circulation system.

[0015] Furthermore, the system can also automatically switch to external circulation mode when it detects a power fluctuation exceeding 2%, or when the humidity in the optical cavity exceeds 40%, the system will automatically shut down the external circulation mode, switch to internal circulation mode, and increase the main channel flow by 50%.

[0016] Furthermore, the radiator adopts an integrated design of laser temperature control and ozone radar gas circulation, and has the dual functions of laser temperature control and ozone radar gas circulation.

[0017] Furthermore, a PTC heating film is installed on the connection surface between the temperature-controlled and uniform heat plate and the laser, and a graphite sheet of high thermal conductivity interface material is installed between the temperature-controlled and uniform heat plate and the radiator.

[0018] Furthermore, the heat sink is made of phase change material with a phase change point of 25°C to 38°C, a latent heat of 220kJ / kg, and a thermal conductivity of 10W / m / K.

[0019] Furthermore, when the ambient temperature is between -40°C and 60°C, the dual-mode gas circulation architecture continues to work alternately; among them, when the ambient temperature is between 15°C and 60°C, the PTC heating film stops working, and the waste heat generated by the laser is dissipated to the external environment based on the thermal coupling architecture. When the ambient temperature is between -40°C and 15°C, the PTC heating film is started to maintain the operating temperature range of the temperature-controlled uniform heat plate heat pipe.

[0020] The beneficial effects of the present invention are:

[0021] The present invention's dynamic gas displacement system significantly improves the detection performance and operational stability of ozone radars through an innovative dual-mode gas circulation architecture and optical-gas-thermal coupling design. The system employs a dual-channel design with primary and secondary circulation channels. The primary channel maintains a baseline gas displacement flow, while the secondary channel activates external circulation mode when power anomalies are detected. Combined with a multi-stage filtration unit, this effectively removes contaminants from the optical cavity, fundamentally addressing the optical cavity contamination issue that traditional solutions struggle to address. This significantly improves laser power stability and reduces differential absorption signal distortion to below 3%.

[0022] In response to the technical bottlenecks in extreme environments, the optical window is coated with a self-cleaning film layer (anti-reflection film layer + hydrophobic film layer + wear-resistant protective layer) to effectively reduce the adhesion of ice crystals in low-temperature environments. The radiator adopts an integrated structure design of laser temperature control and ozone radar gas circulation, and has the dual functions of laser temperature control and ozone radar gas circulation. The radiator serves as both the core heat dissipation component of the laser and the main circulation channel of the gas replacement system. In extremely low-temperature environments (-40°C), this solution effectively solves the problems of condensation and temperature fluctuations on the optical window in extremely low-temperature environments through the integrated structure of ozone radar gas circulation and laser temperature control, self-cleaning film layer, PTC heating film, and radiator phase change material heat storage technology. Compared with traditional electric heating solutions, energy consumption is reduced by 70%, and temperature fluctuations are <±0.5°C, allowing the system to maintain stable operation in an environment of -40°C to +60°C.

[0023] Furthermore, the dynamic gas replacement system utilizes a multi-parameter coordinated control scheme, including airflow and humidity. The system intelligently adjusts airflow velocity and automatically switches to external circulation mode when power fluctuations exceeding 2% are detected, effectively preventing significant laser power loss and differential absorption signal distortion. When optical cavity humidity exceeds 40%, the system automatically switches from external circulation mode to internal circulation mode, increasing the main channel flow by 50% and significantly suppressing water vapor condensation. This makes it particularly suitable for high-precision ozone detection missions in extreme environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a top view of the structure of a gas replacement system for stable detection of ozone radar according to the present invention;

[0025] Figure 2This is an isometric view of the structure of a gas replacement system for stable detection of ozone radar according to the present invention;

[0026] Figure 3 This is a cross-sectional view of the ozone radar structure of the present invention.

[0027] Reference numerals:

[0028] Laser 1, radiator air outlet 2, radiator air inlet 3, laser air outlet 4, laser air inlet 5, first solenoid valve 6, first macromolecular filter 7, first molecular sieve 8, first water-blocking filter membrane 9, diaphragm pump 10, second solenoid valve 11, second water-blocking filter membrane 12, second molecular sieve 13, second macromolecular filter 14, third solenoid valve 15, temperature-controlled uniform heating plate 16, radiator 17, fan 18, laser window lens 19, telescope 20, telescope window lens 21, radar frame 22, radar window lens 23, graphite sheet 24. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and examples.

[0030] The core component of the ozone radar is the laser, and the stability of the laser power directly affects the detection stability, accuracy and reliability. The present application provides an active and sustainable pollution prevention and control solution to ensure the stability of the laser power from the source, thereby improving the detection reliability, accuracy and coverage capability of the ozone radar. In response to the key problem of laser power attenuation during long-term operation of the ozone laser radar, the present invention proposes a gas dynamic replacement system for stable detection of the ozone radar, which adopts a dual-mode gas circulation architecture, including a main channel (referred to as the internal circulation mode) and an auxiliary channel (referred to as the external circulation mode). The purity of the gas inside the laser is ensured through a multi-stage filtering unit, protecting the core optical components and maintaining stable laser output performance. Among them, the main channel is used to maintain the basic gas replacement flow, and the auxiliary channel automatically switches to the external circulation mode when an abnormal laser power is detected, realizing timed and quantitative gas replacement.

[0031] like Figure 2 As shown, the heat generated by the laser 1 is transferred to the temperature-controlled uniform heat plate 16 and efficiently dissipated to the external environment via an integrated heat sink air cooling system (a fan 18 is provided below the heat sink 17 in this embodiment). A graphite sheet 24 is installed between the temperature-controlled uniform heat plate 16 and the heat sink 17 to reduce thermal resistance during heat conduction, thereby improving thermal efficiency. The heat sink 17 utilizes an integrated structure that combines laser temperature control with ozone radar gas circulation, facilitating both laser temperature control and ozone radar gas circulation. The heat sink serves as both the laser's core heat dissipation component and the primary circulation channel for the gas displacement system.

[0032] like Figure 1As shown, the laser air inlet 5, the laser air outlet 4, the radiator air inlet 3, and the radiator air outlet 2 all use quick-insert self-locking connectors, the first solenoid valve 6 is used to control the opening and closing of the internal circulation, the second solenoid valve 11 is used to control the automatic switching between the internal circulation and the external circulation, and the third solenoid valve 15 is used to control the opening and closing of the external circulation.

[0033] In the ozone lidar gas replacement system, the main channel is used to maintain a basic gas replacement flow rate of 1-5 L / min. The main channel uses a diaphragm pump 10 to drive the gas circulation, and the gas is air.

[0034] When the third solenoid valve 15 is closed, the second solenoid valve 11 automatically switches to the internal circulation mode, and the gas at the radiator outlet 2 enters the first multi-stage filtration unit through the first solenoid valve 6, wherein the first multi-stage filtration unit includes a first macromolecular filter 7, a first molecular sieve 8, and a first water-blocking filter membrane 9. The gas enters the laser optical cavity through the multi-stage filtration unit, flows in through the laser air inlet 5, and flows out through the laser air outlet 4. The gas at the laser air outlet 4 passes through the diaphragm pump 10 and the second solenoid valve 11 in turn and flows into the radiator air inlet 3 of the radiator 17, forming an internal circulation system.

[0035] The auxiliary channel automatically activates when power anomalies are detected, thereby achieving timed and quantitative gas replacement. When the first solenoid valve 6 is closed, the second solenoid valve 11 automatically switches to external circulation mode, and the third solenoid valve 15 opens. Gas from the external environment flows through the third solenoid valve 15, passes through the first multi-stage filtration unit, such as the first macromolecular filter 7, the first molecular sieve 8, and the first water-blocking filter membrane 9, and flows into the laser optical cavity. The gas flows in through the laser air inlet 5 and flows out through the laser air outlet 4. The gas at the laser air outlet 4 passes through the diaphragm pump 10, the second solenoid valve 11, and the second multi-stage filtration unit, such as the second water-blocking filter membrane 12, the second molecular sieve 13, and the second macromolecular filter 14, and is discharged to the external environment, preventing external contaminated gas from flowing back into the laser optical cavity, forming an external circulation system.

[0036] like Figure 3 As shown, the laser window lens 19 is installed on the laser 1 , the telescope window lens 21 is installed on the telescope 20 , and the radar window lens 23 is installed on the radar frame 22 . The telescope 20 is located above the laser 1 , and the radar frame 22 covers the entire telescope 20 .

[0037] During the project implementation, the gas dynamic replacement system adopts a modular design, which can be integrated into the side wall of the laser or the main frame of the radar. Compared with the traditional single-channel solution, it significantly improves the emergency handling capability of laser contamination; through dual-channel collaborative control (main cycle + emergency replacement), the contaminated gas replacement can be completed within 30 seconds, and the power attenuation caused by optical component contamination can be suppressed within ±1%; it fundamentally solves the power attenuation and data drift problems caused by optical contamination, and significantly improves the stability of radar detection.

[0038] To address the technical bottlenecks of traditional lidar in extremely low-temperature environments (-40°C), such as high heating power consumption and large optical cavity temperature fluctuations, this invention proposes an innovative "optical-gas-thermal coupled design" solution. This system utilizes optical windows coated with self-cleaning coatings (anti-reflection coating + hydrophobic coating + wear-resistant protective layer), such as the laser window lens 19, telescope window lens 21, and radar window lens 23, to effectively reduce the adhesion of ice crystals in low-temperature environments.

[0039] The heat sink features an integrated design for laser temperature control and ozone radar gas circulation, combining both laser heat dissipation and ozone radar gas circulation. Radiator 17 is constructed from phase change material (PCM) and located beneath the temperature-controlled uniform heat plate 16. The material of radiator 17 is an aluminum alloy / PCM composite. Factors such as phase transition temperature, thermal conductivity, and stability were considered, resulting in a phase transition point of 25°C to 38°C, a latent heat of 220 kJ / kg, and a thermal conductivity of 10 W / m / K. Radiator 17 has an internal flow channel structure, serving as the ozone radar's main circulation channel. This prevents contamination of the laser's optical cavity and condensation on the window lens, thereby ensuring laser power stability.

[0040] The temperature-controlled uniform heat plate 16 is connected to the heat sink 17. A graphite sheet 24, a highly thermally conductive interface material, is installed between the two to reduce interfacial thermal resistance. A copper-water heat pipe is embedded within the temperature-controlled uniform heat plate 16. This effectively diffuses heat and balances temperature, eliminating localized heat accumulation. A PTC (Positive Temperature Coefficient) heating film is installed at the interface between the temperature-controlled uniform heat plate 16 and the laser 1.

[0041] When the ambient temperature is between -40°C and 60°C, the dual-mode gas circulation architecture of the ozone radar continues to work. The internal circulation mode will automatically shut down after running for 2 hours, and then switch to the external circulation mode for 0.5 hours, and so on. Among them, the main channel is used to maintain the basic gas replacement flow rate, and automatically switches to the external circulation mode when the laser power abnormality is detected, so as to achieve timed and quantitative gas replacement. The system can intelligently adjust the airflow rate, and automatically switches to the external circulation mode when the power fluctuation is detected to exceed 2%, effectively preventing the laser power from being greatly reduced and the differential absorption signal from being distorted; or, when the humidity in the optical cavity exceeds 40%, the system will automatically shut down the external circulation mode, switch to the internal circulation mode, and increase the main channel flow by 50%, significantly suppressing the condensation of water vapor. In order to solve the problem of radar data drift caused by laser power fluctuations and increased humidity, the gas dynamic replacement system of the present invention also adopts a multi-parameter collaborative control scheme such as airflow and humidity.

[0042] When the ambient temperature is between 15°C and 60°C, the PTC heating film stops working, and the waste heat generated by the laser 1 is transferred to the temperature-controlled uniform heat plate 16 and then dissipated to the external environment through the radiator 17 based on forced air cooling, thereby ensuring the stability of the laser wavelength and output power.

[0043] When the ambient temperature is between -40°C and 15°C, the PTC heating film is activated. This not only maintains the operating temperature range of the heat pipes on the temperature-controlled uniform heating plate 16, but also actively heats the window lens through the ozone radar's main circulation channel, completely eliminating the risk of condensation on the optical mirror. The PTC heating film preferentially heats the temperature-controlled uniform heating plate 16. The evaporation section of the heat pipe inside the temperature-controlled uniform heating plate 16 absorbs heat, causing the working fluid inside the heat pipe to vaporize. The condensation section releases heat, heating the gas in the radiator 17. The airflow from the temperature-controlled uniform heating plate 16, combined with the heat storage of the phase change material in the radiator 17, preheats the gas in the internal flow channel from -40°C to +20°C before entering the laser optical cavity, completely eliminating the risk of condensation on the mirror. Compared to traditional electric heating solutions, this design reduces energy consumption by 70%, controls temperature fluctuations within ±0.5°C, and ensures stable operation of the system within a wide temperature range of -40°C to +60°C, significantly improving the detection stability, accuracy, and reliability of the ozone radar.

[0044] In summary, the present invention has constructed a complete solution for stable ozone radar detection. Through a dual-mode gas circulation system (adopting a main / auxiliary dual circulation channel design), a light-gas-heat coupling design, and a multi-parameter coordinated control scheme such as airflow and humidity, the detection stability, accuracy, and reliability of the ozone radar have been significantly improved.

[0045] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A gas replacement system for stable detection of ozone radar, characterized in that: It includes a dual-mode gas circulation architecture and a thermal coupling architecture, wherein: The dual-mode gas circulation architecture includes a main channel and an auxiliary channel. The main channel is used to maintain the basic gas replacement flow rate in the laser optical cavity to achieve an internal circulation mode. The auxiliary channel automatically switches to an external circulation mode when abnormal laser power is detected to achieve timed and quantitative gas replacement. The thermal coupling structure is used to dissipate the heat generated by the laser to the external environment, and to preheat the gas in an internal circulation mode before entering the laser optical cavity.

2. A gas replacement system for stable detection of ozone radar according to claim 1, characterized in that: The system also includes a first solenoid valve, a second solenoid valve, and a third solenoid valve, wherein the first solenoid valve is used to control the opening and closing of the internal circulation, the second solenoid valve is used to control the automatic switching between the internal circulation and the external circulation, and the third solenoid valve is used to control the opening and closing of the external circulation.

3. The gas replacement system for stable detection of ozone radar according to claim 2, characterized in that: The thermal coupling structure includes a temperature-controlled uniform heat plate, a radiator, and a fan which are sequentially stacked below the laser.

4. The gas replacement system for stable detection of ozone radar according to claim 3, characterized in that: When the third solenoid valve is closed, the second solenoid valve automatically switches to the internal circulation mode. The gas at the radiator outlet enters the first multi-stage filtration unit through the first solenoid valve, flows into the laser optical cavity through the laser air inlet, and flows out through the laser air outlet. The outflowing gas passes through the diaphragm pump and the second solenoid valve in turn and flows into the radiator air inlet, forming an internal circulation system.

5. The gas replacement system for stable detection of ozone radar according to claim 3, characterized in that: When the first solenoid valve is closed, the second solenoid valve automatically switches to the external circulation mode, and the third solenoid valve opens. The gas in the external environment enters the first multi-stage filtration unit through the third solenoid valve, flows into the laser optical cavity through the laser air inlet, and flows out through the laser air outlet. The outflowing gas passes through the diaphragm pump, the second solenoid valve, and the second multi-stage filtration unit in sequence and is discharged to the external environment, forming an external circulation system.

6. The gas replacement system for stable detection of ozone radar according to claim 1, characterized in that: The system can also automatically switch to external circulation mode when it detects a power fluctuation exceeding 2%, or when the humidity in the optical cavity exceeds 40%, the system will automatically shut down the external circulation mode, switch to internal circulation mode, and increase the main channel flow by 50%.

7. The gas replacement system for stable ozone radar detection according to claim 3, characterized in that: The radiator adopts an integrated design of laser temperature control and ozone radar gas circulation, and has the dual functions of laser temperature control and ozone radar gas circulation.

8. The gas replacement system for stable ozone radar detection according to claim 3, characterized in that: A PTC heating film is installed on the connection surface between the temperature-controlled and uniformly distributed heat plate and the laser, and a graphite sheet made of a high thermal conductivity interface material is installed between the temperature-controlled and uniformly distributed heat plate and the radiator.

9. The gas replacement system for stable ozone radar detection according to claim 3, characterized in that: The radiator is made of phase change material with a phase change point of 25° C. to 38° C., a latent heat of 220 kJ / kg, and a thermal conductivity of 10 W / m / K.

10. The gas replacement system for stable detection of ozone radar according to claim 8, characterized in that: When the ambient temperature is between -40°C and 60°C, the dual-mode gas circulation architecture continues to work alternately; among them, when the ambient temperature is between 15°C and 60°C, the PTC heating film stops working, and the waste heat generated by the laser is dissipated to the external environment based on the thermal coupling architecture. When the ambient temperature is between -40°C and 15°C, the PTC heating film is started to maintain the operating temperature range of the temperature-controlled uniform heat plate heat pipe.

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