High-precision laser water vapor detection system

Abstract

The utility model discloses a high-precision laser water vapor detection system, and belongs to the technical field of pipeline leakage monitoring. The device comprises a laser driving module, a water vapor detection module and a signal processing module, the position of a water vapor absorption line is obtained by directly detecting the concentration of water vapor in the air through a reference gas pool, the laser is regulated and controlled in real time to output and lock the central wavelength, the output wavelength of the laser is locked at 933.86 nm, locking of the central wavelength of output laser is achieved, and the measurement accuracy is improved. The detection precision and stability of the system are improved; the temperature of the heat dissipation block is actively detected and monitored through the thermistor, and the temperature of the Peltier is regulated and controlled in real time through the temperature control circuit, so that the heat dissipation block and the laser are in a constant-temperature working environment, the measurement stability and reliability are improved, and meanwhile, the problems of high cost and wavelength current drift of a semiconductor laser are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of laser spectrum gas detection, in particular to a high-precision laser water vapor detection system. Background Art

[0002] The core of the industrial application of laser water vapor detection technology is to achieve precise control and safety assurance of the production process. By real-time and highly sensitive monitoring of the moisture content in the environment or materials, it can effectively improve product quality, optimize production processes, prevent equipment corrosion, and ensure safe operations in specific industries such as chemicals and pharmaceuticals. This can improve economic benefits while ensuring environmental stability and personnel safety.

[0003] Tunable diode laser absorption spectroscopy (TDLAS) is an important technology for gas detection. It boasts high accuracy, no calibration required, zero drift, and immunity to cross-gas interference. It has been widely applied in safety, environmental protection, industrial processes, metallurgy, chemical engineering, power generation, healthcare, and aerospace. However, the conventionally used DFB semiconductor lasers are expensive. Furthermore, due to the sideways emission principle of the laser chip, their wavelength is significantly affected by temperature, resulting in an elliptical light spot that is difficult to couple. This has hindered the widespread use of TDLAS technology, and has contributed to the limited prevalence of water vapor monitoring in industrial processes. Summary of the Invention

[0004] In response to the above problems, the utility model provides a high-precision laser water vapor detection system, which directly detects the water vapor concentration in the air through a reference gas pool to obtain the position of the water vapor absorption line, and adjusts the laser output to lock the central wavelength in real time, locking the output wavelength of the laser at 933.86nm, thereby locking the output laser center wavelength and improving the accuracy and stability of system detection; actively detects and monitors the temperature of the heat sink through a thermistor, and adjusts the temperature of the Peltier in real time through a temperature control circuit, thereby achieving a constant temperature working environment for the heat sink and the laser, improving measurement stability and reliability, and solving the problems of high cost and wavelength current drift of semiconductor lasers. While ensuring the high-precision performance of the laser water vapor monitoring system, the cost and power consumption of the laser water vapor monitoring system are greatly reduced.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is.

[0006] A high-precision laser water vapor detection system includes a laser driving module, a water vapor detection module and a signal processing module; the laser driving module includes a laser and a current driving module; the water vapor detection module includes a beam splitter, a reference gas cell, a first photodetector, a second photodetector and an absorption chamber.

[0007] Preferably, the laser output by the laser is split into measurement light and reference light after passing through a beam splitter. After the reference light is absorbed by the reference water vapor in the air in the reference gas pool, the laser light carrying the reference water vapor spectrum information in the air is output to the signal processing module through photodetector 1. After processing by the signal processing module, the position of the water vapor absorption line of the reference water vapor in the air is output, and real-time feedback is fed back to control the current driving module to regulate the laser output to lock the central wavelength of the laser. After the measurement light is absorbed by the water vapor to be measured in the absorption chamber, the laser light carrying the water vapor spectrum information is output to the signal processing module through photodetector 2. After calculation and processing by the signal processing module, the concentration of the water vapor to be measured is output.

[0008] Preferably, the laser driving module further includes a heat sink for conducting and dissipating heat from the laser, a thermistor for monitoring the temperature of the heat sink in real time, a Peltier for regulating the temperature of the heat sink, and a temperature control circuit for regulating the temperature of the Peltier according to the temperature of the heat sink monitored in real time by the thermistor.

[0009] Preferably, the thermistor monitors the temperature transmitted from the bottom of the laser to the heat sink in real time, and outputs the monitored heat sink temperature information to the temperature control circuit. The temperature control circuit adjusts the current direction and size of the Peltier according to the heat sink temperature information, thereby adjusting the temperature of the Peltier to further stabilize the operation of the heat sink and the laser.

[0010] Preferably, the laser is a VCSEL laser that can output a specific wavelength of 940 nm.

[0011] Preferably, the locked center wavelength output by the laser is 933.86 nm.

[0012] Preferably, the laser driving module further comprises a fixing plate for fixing the Peltier, the heat sink and the laser.

[0013] Preferably, the water vapor detection module further includes a collimator for collimating the measurement light entering the absorption chamber.

[0014] Preferably, the beam splitter splits the laser light output by the laser into reference light and measurement light at a beam splitting ratio of 5%:95%.

[0015] Preferably, the signal processing module includes a reference signal processing module, an MCU control circuit, a weak signal processing module and a storage communication circuit.

[0016] Due to the adoption of the above technical solution, the utility model has the following beneficial effects.

[0017] (1) The utility model directly detects the water vapor concentration in the air through a reference gas pool to obtain the position of the water vapor absorption line, and adjusts the laser output to lock the central wavelength in real time, locking the output wavelength of the laser at 933.86nm, eliminating the influence of water vapor and temperature in the air on the laser, achieving the locking of the output laser center wavelength, and improving the accuracy and stability of the system detection.

[0018] (2) The utility model actively detects and monitors the temperature of the heat sink through thermistors, and adjusts the temperature of the Peltier in real time through temperature control circuits, thereby achieving a constant temperature working environment for the heat sink and the laser, improving measurement stability and reliability, and solving the problems of high cost and wavelength current drift of semiconductor lasers. It has great practical significance for the promotion and application of tunable semiconductor laser absorption spectroscopy technology.

[0019] (3) The utility model adopts a 940nm VCSEL laser commonly available on the market, which has an extremely low operating threshold, low power consumption, and can quickly respond to higher modulation frequencies, greatly reducing the cost of the system and providing a good foundation for the industrialization of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following discusses the fabrication and application of preferred embodiments of the present invention in detail. However, it should be understood that the present invention provides numerous applicable utility concepts that can be implemented in a variety of specific environments. The specific embodiments discussed are intended only to illustrate specific ways to fabricate and use the present invention and do not limit the scope of the present invention. Persons skilled in the art will readily be able to derive additional drawings from these drawings without inventive effort.

[0021] Figure 1 It is a structural diagram of the present utility model.

[0022] Among them, 1-fixed plate; 2-Peltier; 3-heat sink; 4-thermistor; 5-laser; 6-beam splitter; 7-reference gas cell; 8-photodetector 1; 9-reference signal processing module; 10-temperature control circuit; 11-current drive module; 12-collimator; 13-photodetector 2; 14-absorption chamber; 15-MCU control circuit; 16-weak signal processing module; 17-storage communication circuit. DETAILED DESCRIPTION

[0023] The following detailed discussion discusses the fabrication and use of preferred embodiments of the present invention. However, it should be understood that the present invention provides numerous applicable concepts that can be implemented in a variety of specific contexts. The specific embodiments discussed are intended only to illustrate specific ways to fabricate and use the present invention and are not intended to limit the scope of the present invention.

[0024] The utility model directly detects the water vapor concentration in the air through the reference gas pool 7 to obtain the position of the water vapor absorption line, and adjusts the output of the laser 5 to lock the central wavelength in real time, locking the output wavelength of the laser 5 at 933.86nm, eliminating the influence of water vapor and temperature in the air on the laser 5, achieving the locking of the output laser center wavelength, and improving the accuracy and stability of the system detection.

[0025] The following is combined with Figure 1 Further elaborate.

[0026] A high-precision laser water vapor detection system includes a laser driver module, a water vapor detection module, and a signal processing module. The laser driver module includes a laser 5 and a current driver module 11. The water vapor detection module includes a beam splitter 6, a reference gas cell 7, a photodetector 1 8, a photodetector 2 13, and an absorption chamber 14. The laser light output by the laser 5 is split into measurement light and reference light after passing through the beam splitter 6. After the reference light is absorbed by the reference water vapor in the air within the reference gas cell 7, the laser light carrying the spectral information of the reference water vapor in the air is output through the photodetector 1 8 to the signal processing module. After processing by the signal processing module, the position of the water vapor absorption line of the reference water vapor in the air is output, and the current driver module 11 is controlled by real-time feedback to adjust the laser 5 to output laser light with a locked central wavelength. After the measurement light is absorbed by the water vapor to be measured in the absorption chamber 14, the laser light carrying the spectral information of the water vapor is output through the photodetector 2 13 to the signal processing module. After calculation and processing by the signal processing module, the concentration of the water vapor to be measured is output.

[0027] The laser drive module also includes a heat sink 3 for conducting and dissipating heat from the laser 5, a thermistor 4 for real-time monitoring of the temperature of the heat sink 3, a Peltier 2 for regulating the temperature of the heat sink 3, and a temperature control circuit 10 for regulating the temperature of the Peltier 2 based on the temperature of the heat sink 3 monitored in real time by the thermistor 4. The thermistor 4 monitors the temperature of the heat sink 3 from the bottom of the laser 5 in real time and outputs the monitored temperature information of the heat sink 3 to the temperature control circuit 10. The temperature control circuit 10 then regulates the direction and magnitude of the current in the Peltier 2 based on the temperature information of the heat sink 3, thereby regulating the temperature of the Peltier 2 to further stabilize the operation of the heat sink 3 and the laser 5.

[0028] The laser 5 uses a VCSEL laser 5 that can output a specific wavelength of 940nm. The locked center wavelength output by the laser 5 is 933.86nm. The laser driving module also includes a fixing plate 1 for fixing the Peltier 2, the heat sink 3 and the laser 5. The water vapor detection module also includes a collimator 12 for collimating the measurement light entering the absorption chamber 14. The beam splitter 6 beams the laser output by the laser 5 into reference light and measurement light at a beam splitting ratio of 5%:95%. The signal processing module includes a reference signal processing module 9, an MCU control circuit 15, a weak signal processing module 16 and a storage communication circuit 17.

[0029] Further, such as Figure 1 The high-precision laser water vapor detection system shown in the figure includes a laser driver module, a water vapor detection module, and a signal processing module. The laser driver module includes a laser 5, a current driver module 11, a heat sink 3 for conducting and dissipating heat from the laser 5, a thermistor 4 for real-time monitoring of the temperature of the heat sink 3, a Peltier 2 for regulating the temperature of the heat sink 3, a fixing plate 1 for securing the Peltier 2, the heat sink 3, and the laser 5, and a temperature control circuit 10 for regulating the temperature of the Peltier 2 based on the temperature of the heat sink 3 monitored in real time by the thermistor 4. The laser 5 utilizes a VCSEL laser 5 that can output a specific wavelength of 940 nm. The locked center wavelength of the output of the laser 5 is 933.86 nm. The thermistor 4 monitors the temperature transmitted from the bottom of the laser 5 to the heat sink 3 in real time, and outputs the monitored temperature information of the heat sink 3 to the temperature control circuit 10. The temperature control circuit 10 adjusts the current direction and magnitude of the Peltier 2 according to the temperature information of the heat sink 3, thereby adjusting the temperature of the Peltier 2 to further stabilize the operation of the heat sink 3 and the laser 5.

[0030] The water vapor detection module includes a beam splitter 6, a reference gas cell 7, a first photodetector 8, a second photodetector 13, an absorption chamber 14, and a collimator 12 for collimating the measurement light entering the absorption chamber 14. The beam splitter 6 splits the laser light output by the laser 5 into reference light and measurement light at a splitting ratio of 5%:95%. The signal processing module includes a reference signal processing module 9, an MCU control circuit 15, a weak signal processing module 16, and a storage and communication circuit 17.

[0031] The laser output by the laser 5 is split into measurement light and reference light after passing through the beam splitter 6. After the reference light is absorbed by the reference water vapor in the air in the reference gas pool 7, the laser light carrying the reference water vapor spectrum information in the air is output to the signal processing module through the photodetector 1 8. After processing by the signal processing module, the water vapor absorption line position of the reference water vapor in the air is output, and the current driving module 11 is controlled by real-time feedback to regulate the laser 5 to output the laser with the locked central wavelength; after the measurement light is absorbed by the water vapor to be measured in the absorption chamber 14, the laser light carrying the water vapor spectrum information is output to the signal processing module through the photodetector 2 13. After calculation and processing by the signal processing module, the concentration of the water vapor to be measured is output.

[0032] The heat sink 3 is located at the bottom of the laser 5 and is used for heat conduction and heat dissipation. The external Peltier 2 of the laser 5 is closely attached to the heat sink 3 on one side and to the housing on the other side, and is used for heating and cooling the heat sink 3. The thermistor 4 is built into the inner hole of the heat sink 3 and is used to monitor the temperature of the heat sink 3 in real time. The temperature control circuit 10 feedback controls the current direction and magnitude of the Peltier 2 according to the monitored temperature of the heat sink 3, thereby stabilizing the temperature of the laser heat sink 3 and maintaining a relatively stable temperature environment for the laser 5. The fixing plate 1 fixes the heat sink 3, Peltier 2, and thermistor 4 on the laser 5 and is connected to the circuit board.

[0033] The beam splitter 6 is a 5%:95% ratio optical beam splitter 6, which is used for splitting light. The input end of the beam splitter is connected to the output end of the laser 5, and the two output ends of the beam splitter 6 are connected to the reference gas pool 7 and the absorption chamber 14 respectively. The reference gas pool 7 is used to emit and receive reference light. It is exposed to natural air and uses the absorption position of water vapor in the air as the reference position of the output center wavelength of the laser 5. The MCU control circuit 15 has the functions of signal acquisition, filtering, processing, and calculation. In addition, the MCU is also used to control the current modulation signal output of the laser 5. The storage communication circuit 17 is used to store relevant parameter data and data interaction of external devices.

[0034] This utility model utilizes TDLAS technology, a technique used in laser spectroscopy gas absorption detection, to monitor water vapor. The wavelength of the output laser from a VCSEL laser 5 is controlled by high-frequency current modulation. The laser light is then coupled to a fiber and fed into a 5%:95% beam splitter 6. The 95% split beam is fed into an absorption chamber 14. After absorption by the water vapor to be measured, the laser light carrying the gas spectrum information is received by a photodetector 13. The resulting photoelectrically converted current signal undergoes signal processing, filtering, and algorithmic calculations to ultimately determine the water vapor concentration. The other 5% split beam serves as a reference laser, used to monitor and lock the output center wavelength of the laser 5. This reference laser light is fed into a reference absorption path exposed to natural air, passes through and is absorbed by water vapor in the air, and is received by a photodetector 1. The resulting photoelectrically converted reference signal is processed by a circuit to determine the position of the water vapor absorption line. This signal then feeds back to control the current driving the DAC output of the laser 5, adjusting the laser's center wavelength to a fixed position and improving the reliability and stability of the measurement system.

[0035] The utility model actively detects and monitors the temperature of the heat sink 3 through the thermistor 4, and adjusts the temperature of the Peltier 2 in real time through the temperature control circuit 10, thereby achieving a constant temperature working environment for the heat sink 3 and the laser 5, improving measurement stability and reliability, and solving the problems of high cost and wavelength current drift of the semiconductor laser 5. By adopting a 940nm common VCSEL laser 5 on the market, its operating threshold is extremely low, power consumption is low, and it can quickly respond to a higher modulation frequency, which greatly reduces the cost of the system and provides a good foundation for the industrialization of the system.

[0036] Although the specification has been described in detail, it should be understood that various changes, substitutions, and modifications may be made without departing from the spirit and scope of the present invention as defined by the appended claims. In addition, the specific embodiments described are not intended to limit the scope of the present invention. A person of ordinary skill in the art will readily understand based on the present invention that currently existing or later developed processes, machines, manufactures, material compositions, means, methods, or steps may perform substantially the same functions or obtain substantially the same results as the embodiments of the present invention. Therefore, the appended claims are intended to include such processes, machines, manufactures, material compositions, means, methods, or steps within their scope.

Claims

1. A high-precision laser water vapor detection system, characterized by: It includes a laser driving module, a water vapor detection module and a signal processing module; the laser driving module includes a laser and a current driving module; the water vapor detection module includes a beam splitter, a reference gas cell, a photodetector 1, a photodetector 2 and an absorption chamber; The laser output by the laser is split into measurement light and reference light after passing through a beam splitter. After the reference light is absorbed by the reference water vapor in the air in the reference gas pool, the laser light carrying the reference water vapor spectrum information in the air is output to the signal processing module through the first photodetector. After processing by the signal processing module, the position of the water vapor absorption line of the reference water vapor in the air is output, and real-time feedback is fed back to control the current driving module to regulate the laser output to lock the central wavelength of the laser. After the measurement light is absorbed by the water vapor to be measured in the absorption chamber, the laser light carrying the water vapor spectrum information is output to the second photodetector through the signal processing module. After calculation and processing by the signal processing module, the concentration of the water vapor to be measured is output.

2. A high-precision laser water vapor detection system according to claim 1, characterized in that: The laser driving module also includes a heat sink for conducting and dissipating heat from the laser, a thermistor for monitoring the temperature of the heat sink in real time, a Peltier for regulating the temperature of the heat sink, and a temperature control circuit for regulating the temperature of the Peltier according to the temperature of the heat sink monitored in real time by the thermistor.

3. The high-precision laser water vapor detection system according to claim 2, characterized in that: The thermistor monitors the temperature transmitted from the bottom of the laser to the heat sink in real time, and outputs the monitored heat sink temperature information to the temperature control circuit. The temperature control circuit adjusts the current direction and size of the Peltier according to the heat sink temperature information, thereby adjusting the temperature of the Peltier to further stabilize the operation of the heat sink and the laser.

4. The high-precision laser water vapor detection system according to claim 3, characterized in that: The laser adopts a VCSEL laser which can output a specific wavelength of 940nm.

5. The high-precision laser water vapor detection system according to claim 4, characterized in that: The locked center wavelength output by the laser is 933.86 nm.

6. The high-precision laser water vapor detection system according to claim 2, characterized in that: The laser driving module further comprises a fixing plate for fixing the Peltier, the heat sink and the laser.

7. The high-precision laser water vapor detection system according to claim 1, characterized in that: The water vapor detection module further includes a collimator for collimating the measurement light entering the absorption chamber.

8. The high-precision laser water vapor detection system according to claim 1, characterized in that: The beam splitter splits the laser light output by the laser into reference light and measurement light at a beam splitting ratio of 5%:95%.

9. The high-precision laser water vapor detection system according to claim 2, characterized in that: The signal processing module includes a reference signal processing module, an MCU control circuit, a weak signal processing module and a storage communication circuit.

Images