TDLAS water vapor sensor calibration device

Abstract

The utility model discloses a TDLAS water vapor sensor calibration device which comprises a gas chamber, a water vapor supply unit, a reference water vapor sensor and a DLAS water vapor sensor. The reference water vapor sensor and the DLAS water vapor sensor are mounted at one end of the air chamber; the water vapor supply unit is connected with an air inlet of the air chamber; a diffuse reflection plate and a distance adjusting unit are arranged in the air chamber; the diffuse reflection plate is arranged at one end far away from the DLAS water vapor sensor and faces the DLAS water vapor sensor; the distance adjusting unit is used for adjusting the distance between the diffuse reflection plate and the DLAS water vapor sensor. According to the utility model, the distance between the diffuse reflection plate and the TDLAS water vapor sensor is adjusted through the distance adjusting unit, so that water vapor concentration calibration experiments under different distances are realized; the measurement distance is adjusted by adjusting the diffuse reflection plate to move through the linear guide rail, equipment in the air chamber can be conveniently arranged, and operation is convenient; water vapor is supplied in a dry / wet gas mixing mode, the water vapor concentration can be conveniently adjusted, and a humidity-controllable water vapor environment is constructed.

Description

Technical Field

[0001] The utility model relates to a field, in particular to a calibration device for a TDLAS water vapor sensor. Background Technique

[0002] Water vapor is the most important greenhouse gas in the atmosphere and plays an important role in the water and energy balance of the earth. Reliable observation and accurate estimation of atmospheric water vapor (H2O) flux are crucial for ecosystem management and the development of earth system models.

[0003] The TDLAS water vapor sensor emits a laser beam and then realizes water vapor concentration measurement according to the principle of tunable diode laser absorption spectroscopy (TDLAS) and distance measurement according to the TOF principle. To ensure the detection accuracy of the TDLAS water vapor sensor, the TDLAS water vapor sensor needs to be calibrated.

[0004] Patent CN 106596466 B discloses a calibration device and method for a fiber optic sensor humidity measurement, and specifically discloses that the device includes a fiber optic sensor humidity measurement host to be calibrated, a thermostatic and humidistatic chamber, and an optical coupler chamber. The fiber optic sensor humidity measurement host is connected to an analysis computer, and the analysis computer is used to calibrate the humidity compensation parameters of the fiber optic sensor humidity measurement host. The optical coupler chamber is equipped with a fiber collimator and a PIN photodiode, and the two are arranged on a horizontal guide rail to ensure that the collimator and the diode are coaxial. The fiber collimator emits light, and the PIN photodiode receives light and converts it into an electrical signal. A controller controls the horizontal movement of the PIN photodiode on the horizontal guide rail to adjust the distance between the PIN photodiode and the collimator. The optical coupler chamber is arranged in the thermostatic and humidistatic chamber, and an optical fiber line connects the measurement host and the collimator. This patent realizes the rapid and stable calibration of the TDLAS humidity sensor by adjusting the movement of the PIN photodiode, thereby adjusting the distance between the PIN photodiode and the collimator. However, the laser emission module and the laser reception module of the TDLAS water vapor sensor are integrated together, and the distance between the laser emission module and the laser reception module cannot be directly adjusted; and in the above patent, when adjusting the PIN photodiode, the internal wiring of the gas chamber needs to be considered, and the operation is very inconvenient.

[0005] Therefore, in the face of the above problems, it is an urgent problem to be solved at present to design a calibration device for a TDLAS water vapor sensor that can measure the water vapor concentration at different distances. Content of the Utility Model

[0006] The purpose of the utility model is to provide a calibration device for a TDLAS water vapor sensor to solve the problem that the current TDLAS water vapor sensor cannot calibrate the water vapor concentration at different distances.

[0007] To solve the above technical problems, the present invention provides a calibration device for a TDLAS water vapor sensor, which includes a gas chamber, a water vapor supply unit, a reference water vapor sensor, and a DLAS water vapor sensor; the reference water vapor sensor and the DLAS water vapor sensor are installed at one end of the gas chamber; the water vapor supply unit is connected to the air inlet of the gas chamber; a diffuse reflection plate and a distance adjustment unit are provided in the gas chamber; the diffuse reflection plate is arranged at the end far from the DLAS water vapor sensor and faces the DLAS water vapor sensor; the distance adjustment unit is used to adjust the distance between the diffuse reflection plate and the DLAS water vapor sensor.

[0008] Further, the water vapor supply unit includes a first mass flowmeter, a first control valve, and a bubbling humidifier connected in sequence. The air outlet end of the first mass flowmeter is connected to the air inlet of the gas chamber, and the air inlet end of the bubbling humidifier is connected to the air outlet end of a gas storage tank for storing dry nitrogen.

[0009] Further, the water vapor supply unit further includes a second mass flowmeter and a second control valve connected in sequence. The air outlet end of the second mass flowmeter and the air outlet end of the first mass flowmeter are connected to the air inlet of the gas chamber through a first three-way valve, and the air inlet end of the bubbling humidifier and the air inlet end of the second control valve are connected to the gas supply end of the gas storage tank through a second three-way valve.

[0010] Further, a pressure reducing valve is provided between the first three-way valve and the air inlet of the gas chamber.

[0011] Further, the distance adjustment unit includes a linear guide rail arranged at the bottom of the gas chamber along the laser light path emitted by the TDLAS water vapor sensor and a driver for driving the linear guide rail to move. The diffuse reflection plate is vertically installed on the slider of the linear guide rail.

[0012] Further, the diffuse reflection plate is an aluminum plate, and a barium sulfate nanoparticle coating is provided on the side of the aluminum plate facing the TDLAS water vapor sensor.

[0013] Further, a viewing window for observing the internal situation of the gas chamber is installed on the side of the gas chamber, and a scale line for displaying the distance between the diffuse reflection plate and the DLAS water vapor sensor is provided on the side of the linear guide rail.

[0014] Further, the driver is a servo motor or an adjusting handle.

[0015] Further, two reinforcing ribs in a "field" shape are provided on the top of the gas chamber, and the air inlet and air outlet of the gas chamber are respectively arranged at the middle intersection of the "field" - shaped reinforcing ribs.

[0016] The beneficial effects of the present utility model are as follows:

[0017] 1. By adjusting the distance between the diffuse reflection plate and the TDLAS water vapor sensor through the distance adjustment unit, the water vapor concentration calibration experiment at different distances can be realized;

[0018] 2. By adjusting the movement of the diffuse reflection plate through a linear guide to achieve the adjustment of the measurement distance, it is convenient to arrange the equipment in the gas chamber and is easy to operate.

[0019] 3. By adopting the method of supplying water vapor in a dry / wet mixed manner, it is convenient to adjust the water vapor concentration and construct a water vapor environment with controllable humidity. Description of the Drawings

[0020] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The same reference numerals are used to represent the same or similar parts in these drawings. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

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

[0022] Figure 2 It is a front view of an embodiment of the present utility model.

[0023] Figure 3 It is a top view of the gas chamber of an embodiment of the present utility model.

[0024] Wherein: 1. Gas chamber; 11. Inlet port; 12. Exhaust port; 13. Visual window; 14. Reinforcing rib; 2. Diffuse reflection plate; 21. Support plate; 3. Linear guide; 31. Slide block; 32. Scale line; 4. Reference water vapor sensor; 41. Transmitter head; 5. TDLAS water vapor sensor; 51. Data transmission module; 6. Driver; 61. Controller; 7. Water vapor supply unit; 71. Pressure reducing valve; 72. First three-way valve; 73. First mass flowmeter; 731. First control valve; 732. Bubble humidifier; 74. Second mass flowmeter; 741. Second control valve; 75. Second three-way valve; 76. Gas storage tank. Detailed Embodiment

[0025] As Figure 1The TDLAS water vapor sensor 5 calibration device shown in the figure includes a gas chamber 1, a water vapor supply unit 7, a reference water vapor sensor 4, and a DLAS water vapor sensor; the reference water vapor sensor 4 and the DLAS water vapor sensor are installed at one end of the gas chamber 1; the water vapor supply unit 7 is connected to the air inlet 11 of the gas chamber 1; a diffuse reflection plate 2 and a distance adjustment unit are provided in the gas chamber 1; the diffuse reflection plate 2 is arranged at the end far from the DLAS water vapor sensor and faces the DLAS water vapor sensor; the distance adjustment unit is used to adjust the distance between the diffuse reflection plate 2 and the DLAS water vapor sensor. By adjusting the distance between the diffuse reflection plate 2 and the TDLAS water vapor sensor 5 through the distance adjustment unit, the water vapor concentration calibration experiment at different distances can be realized, and the calibration of the water vapor concentration at different distances can be measured.

[0026] Among them, the gas chamber 1 is used to form a closed and stable humidity atmosphere environment to realize the TDLAS signal concentration calibration. The cavity of the gas chamber 1 is designed with all-metal materials, holes are reserved at the positions of each sensor, and fixing and sealing are carried out by means of rubber rings, screws, flanges, etc. The reference water vapor sensor 4 adopts a VAISALA dew point sensor to realize high-precision absolute water vapor concentration measurement. The signal value of the reference water vapor sensor is read through the transmitter head 41, the actual humidity value of the TDLAS water vapor sensor 5 is obtained through the data transmission module 51, and then these two groups of data are recorded and fitted to obtain the relationship between the TDLAS probe signal and the actual water vapor concentration signal.

[0027] According to an embodiment of the present application, the water vapor supply unit 7 includes a first mass flowmeter 73, a first control valve 731, and a bubbling humidifier 732 connected in sequence. The air outlet end of the first mass flowmeter 73 is connected to the air inlet 11 of the gas chamber 1, and the air inlet end of the bubbling humidifier 732 is connected to the air outlet end of a gas storage tank 76 for storing dry nitrogen. The high-purity dry nitrogen in the gas storage tank 76 forms wet gas through the bubbling humidifier 732, and then enters the gas chamber 1 through the first control valve 731 and the first mass flowmeter 73 in sequence to form a water vapor environment.

[0028] According to an embodiment of the present application, the water vapor supply unit 7 further includes a second mass flowmeter 74 and a second control valve 741 connected in sequence. The outlet end of the second mass flowmeter 74 and the outlet end of the first mass flowmeter 73 are connected to the inlet port 11 of the gas chamber 1 through a first three-way valve 72. The inlet end of the bubbling humidifier 732 and the inlet end of the second control valve 741 are connected to the gas supply end of the gas storage tank 76 through a second three-way valve 75. This embodiment supplies water vapor in a dry / wet gas mixing manner; first, the high-purity dry nitrogen in the gas storage tank 76 is divided into two paths. One path is humidified by the bubbling method to form a wet gas channel, and the other path is used as a dry gas channel. The two paths of gas each pass through a mass flowmeter (MFC) to achieve flow rate control and proportional mixing, thereby controlling the humidity of the mixed gas. The mixed gas is introduced into the cavity, and after a certain period of circulation and stabilization, a water vapor environment with controllable humidity can be constructed.

[0029] According to an embodiment of the present application, a pressure reducing valve 71 is provided between the first three-way valve 72 and the inlet port 11 of the gas chamber 1. By setting the pressure reducing valve 71, the air pressure in the gas chamber 1 can be adjusted.

[0030] According to an embodiment of the present application, the distance adjustment unit includes a linear guide rail 3 provided at the bottom of the gas chamber 1 along the laser optical path emitted by the TDLAS water vapor sensor 5 and a driver 6 for driving the linear guide rail 3 to move. The diffuse reflection plate 2 is vertically installed on the slider 31 of the linear guide rail 3. The displacement stroke range of the linear guide rail 3 covers 5 - 25 cm, and the volume of the linear guide rail 3 is designed in a minimized manner to minimize the volume of the airtight cavity and ensure the stability of the water vapor concentration environment.

[0031] According to an embodiment of the present application, the diffuse reflection plate 2 is an aluminum plate, and a barium sulfate nanoparticle coating is provided on the side of the aluminum plate facing the TDLAS water vapor sensor. By setting the barium sulfate nanoparticle coating on the surface of the aluminum plate, the diffuse reflection plate has good spectral uniformity and reflection efficiency, so as to improve the signal reception effect of the TDLAS probe. A support plate 21 is vertically installed on the slider 31 of the linear guide rail 3, and the diffuse reflection plate 2 is fixed on the side of the support plate 21 facing the TDLAS water vapor sensor.

[0032] According to an embodiment of the present application, a viewing window 13 for observing the internal situation of the gas chamber 1 is installed on the side of the gas chamber 1 (as Figure 2 shown), and a scale line for displaying the distance between the diffuse reflection plate 2 and the DLAS water vapor sensor is provided on the side of the linear guide rail 3. By setting the scale line, it is convenient to directly observe the distance between the diffuse reflection plate 2 and the DLAS water vapor sensor during the adjustment of the diffuse reflection plate 2 in the experimental process.

[0033] According to an embodiment of the present application, the driver 6 is a servo motor or an adjustment handle. During the experiment, the servo motor can be controlled by the controller 61 to electrically control the linear guide 3, or the linear guide 3 can be manually controlled by the adjustment handle.

[0034] According to an embodiment of the present application, as Figure 3 shown, two reinforcing ribs 14 in a "field" shape are provided at the top of the air chamber 1, and the air inlet 11 and the air outlet of the air chamber 1 are respectively arranged at the middle intersection of the "field" - shaped reinforcing ribs 14.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A TDLAS water vapor sensor calibration device, characterized in that: It includes an air chamber, a water vapor supply unit, a reference water vapor sensor, and a DLAS water vapor sensor; the reference water vapor sensor and the DLAS water vapor sensor are installed at one end of the air chamber; the water vapor supply unit is connected to the air inlet of the air chamber; A diffuse reflection plate and a distance adjustment unit are provided in the air chamber; the diffuse reflection plate is arranged at the end far from the DLAS water vapor sensor and faces the DLAS water vapor sensor; the diffuse reflection plate is installed on the distance adjustment unit, and the distance between the diffuse reflection plate and the DLAS water vapor sensor is adjusted through the distance adjustment unit.

2. The TDLAS water vapor sensor calibration device according to claim 1, characterized in that: The water vapor supply unit includes a first mass flowmeter, a first control valve, and a bubbling humidifier connected in sequence. The outlet end of the first mass flowmeter is connected to the air inlet of the air chamber, and the inlet end of the bubbling humidifier is connected to the outlet end of a gas storage tank for storing dry nitrogen.

3. The TDLAS water vapor sensor calibration device according to claim 2, characterized in that: The water vapor supply unit further includes a second mass flowmeter and a second control valve connected in sequence. The outlet end of the second mass flowmeter and the outlet end of the first mass flowmeter are connected to the air inlet of the air chamber through a first three-way valve, and the inlet end of the bubbling humidifier and the inlet end of the second control valve are connected to the gas supply end of the gas storage tank through a second three-way valve.

4. The TDLAS water vapor sensor calibration device according to claim 3, characterized in that: A pressure reducing valve is provided between the first three-way valve and the air inlet of the air chamber.

5. The TDLAS water vapor sensor calibration device according to claim 1, characterized in that: The distance adjustment unit includes a linear guide rail arranged at the bottom of the air chamber along the laser light path emitted by the TDLAS water vapor sensor and a driver for driving the linear guide rail to move. The diffuse reflection plate is vertically installed on the slider of the linear guide rail.

6. The TDLAS water vapor sensor calibration device according to claim 5, characterized in that: The diffuse reflection plate is an aluminum plate, and a barium sulfate nanoparticle coating is provided on the side of the aluminum plate facing the TDLAS water vapor sensor.

7. The TDLAS water vapor sensor calibration device according to claim 5, characterized in that: A viewing window for observing the internal situation of the air chamber is installed on the side of the air chamber, and a scale line for showing the distance between the diffuse reflection plate and the DLAS water vapor sensor is provided on the side of the linear guide rail.

8. The TDLAS water vapor sensor calibration device according to claim 5 or 6, characterized in that: The driver is a servo motor or an adjustment handle.

9. The TDLAS water vapor sensor calibration device according to claim 1, characterized in that: Two reinforcing ribs in a "field" shape are provided on the top of the air chamber, and the air inlet and air outlet of the air chamber are respectively arranged at the middle intersection of the "field" shaped reinforcing ribs.

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