Online calibration and precision measuring and calculating device for open-circuit gas analyzer

Abstract

The invention discloses an online calibration and precision measurement and calculation device for an open-circuit gas analyzer. The online calibration and precision measurement and calculation device comprises the open-circuit gas analyzer, the open-circuit gas analyzer is sleeved with the sleeve, a gap is reserved between the sleeve and the open-circuit gas analyzer, a sealing mechanism is arranged between the sleeve and the open-circuit gas analyzer, the bottom face of the open-circuit gas analyzer is fixedly connected with a bottom plate, the bottom plate is fixedly connected with a plurality of supporting columns, the top ends of the supporting columns are fixedly connected with a protection box, and the sleeve is slidably connected to the supporting columns. A threaded rod is rotatably connected between the open-circuit gas analyzer and the protection box, a rotating shaft is rotatably connected in the protection box, extends out of the protection box and is fixedly connected with the threaded rod, the motor is in transmission connection with the rotating shaft, a gas inlet pipe and a gas outlet pipe are mounted on the sleeve, and electromagnetic valves are mounted on the gas inlet pipe and the gas outlet pipe. According to the sleeve, online calibration and precision measurement and calculation of the open-circuit gas analyzer can be facilitated, a certain protection effect can be achieved on open-circuit gas analysis, and the convenience and practicability of equipment are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of open-circuit gas analyzer calibration and testing technology, and in particular to an online calibration and accuracy measurement device for open-circuit gas analyzers. Background Technology

[0002] Gas analyzers based on laser absorption spectroscopy have advantages such as high spectral resolution, high measurement accuracy, and fast response speed, and are increasingly being used in fields such as atmospheric environment and greenhouse gas emission monitoring. Based on their instrument structure, these instruments can be divided into open-circuit and closed-circuit structures.

[0003] Among them, the open-circuit laser gas analyzer, after the signal is emitted from the light source, is reflected multiple times in the air by two optical mirrors before finally entering the optical detector to complete the detection of light signal intensity and online calculation of gas concentration. The open-circuit gas analyzer can capture high-frequency turbulent changes in atmospheric gas concentration in situ without disturbance. Using these measurement data, based on the eddy covariance method, the surface emission (upward) or deposition (downward) flux of atmospheric components (i.e., the amount of matter passing through a unit area per unit time) can be calculated continuously at high frequency. The aforementioned eddy covariance method is currently the standard method for measuring gas emission or deposition fluxes (especially carbon dioxide and water vapor fluxes) between land and atmosphere. The high-frequency flux data obtained based on this method has become a core data source for land-atmosphere interaction research. With the advancement of mid-infrared laser absorption spectroscopy technology, new open-circuit gas analyses are constantly emerging, and the target gases for measurement have been expanded to trace gases such as methane, nitrous oxide, and ammonia. However, these open-circuit laser gas analyzers for trace gases generally face the following four problems and needs in long-term field observations:

[0004] First, the optical reflector of the open-circuit gas analyzer is completely exposed to the air. Due to environmental factors, the reflector will experience varying degrees of mechanical wear over time. At the same time, the intrinsic parameters of key optical components will drift over time. If the initial calibration parameters are used to perform concentration inversion calculations, the concentration measurement value will deviate from the true value. Therefore, the analyzer needs to be calibrated regularly to ensure the accuracy of the measured concentration.

[0005] Secondly, instrument accuracy, as a key performance parameter of gas analyzers, is essentially a measure of the repeatability of measurement results and is directly related to the instrument's noise level (higher accuracy indicates a better signal-to-noise ratio). In the field of gas flux monitoring based on eddy covariance technology, flux calculation relies on the accurate acquisition of high-frequency (≥10Hz) concentration fluctuation data, making instrument accuracy a core requirement. If the instrument's measurement accuracy is insufficient, it cannot accurately capture minute changes in atmospheric concentration; these real change signals will be masked by noise, and the calculated flux will be unreliable. The accuracy of open-circuit analyzers is easily affected by environmental conditions; therefore, it is necessary to periodically measure and optimize their values ​​to ensure the long-term reliability of flux observation data traceability.

[0006] Third, when an open-circuit laser gas analyzer operates outdoors, the heat generated by the laser and the temperature rise of the unit caused by direct sunlight create a superimposed thermal effect, which is particularly significant in summer. When the built-in temperature control module cannot effectively eliminate this heat load, the laser's operating wavelength will deviate from the set value due to thermal drift, causing a shift in the absorption spectrum peak position and consequently resulting in errors in gas concentration measurement.

[0007] Fourth, when the open-circuit analyzer is used for unattended field observations, it may encounter extreme weather such as hail, freezing rain, and sandstorms. In particular, such extreme events have become increasingly frequent in recent years. When these events occur, the optical mirrors of the instrument are at risk of mechanical damage.

[0008] To address these issues, an online calibration and accuracy calculation device for open-circuit gas analyzers is proposed. Summary of the Invention

[0009] The purpose of this invention is to provide an online calibration and accuracy calculation device for an open-circuit gas analyzer, so as to solve the problems existing in the prior art.

[0010] To achieve the above objectives, the present invention provides the following solution: The present invention provides an online calibration and accuracy calculation device for an open-circuit gas analyzer, comprising:

[0011] Open-circuit gas analyzer;

[0012] A sleeve is fitted over the open-circuit gas analyzer, with a gap between the sleeve and the analyzer. A sealing mechanism is provided between the sleeve and the analyzer. A base plate is fixedly connected to the bottom of the analyzer, and several support columns are fixedly connected to the base plate. A protective box is fixedly connected to the top of each support column. The sleeve is slidably connected to the support column. A threaded rod is rotatably connected between the analyzer and the protective box. A rotating shaft is rotatably connected inside the protective box, extending out of the box and fixedly connected to the threaded rod. A motor is fixedly connected inside the protective box, and the motor is driven by the rotating shaft. An inlet pipe and an exhaust pipe are installed on the sleeve, and both are equipped with solenoid valves.

[0013] Preferably, the sealing mechanism includes a first sealing ring, a second sealing ring, and an annular plate. The annular plate is fixedly connected to the open-circuit gas analyzer, the first sealing ring is fixedly connected to the inner edge of the sleeve, the second sealing ring is fixedly connected to the base plate, and an annular groove is provided on the sleeve, which corresponds to the second sealing ring.

[0014] Preferably, a plurality of first connecting rods are fixedly connected to the sleeve, a movable ring is threadedly connected to the threaded rod, a plurality of second connecting rods are fixedly connected between the first connecting rods and the movable ring, a plurality of positioning rings are fixedly connected to the outer wall of the sleeve, and the support column passes through the positioning rings.

[0015] Preferably, a gear ring is fixedly connected to the rotating shaft, and a gear is fixedly connected to the output shaft of the motor, the gear meshing with the gear ring.

[0016] Preferably, a pad is fixedly connected to the open-circuit gas analyzer, and the threaded rod is rotatably connected to the pad.

[0017] Preferably, a number of reinforcing rods are fixedly connected between the protective box and the open-circuit gas analyzer.

[0018] The present invention discloses the following technical effects:

[0019] 1. In this device, when the open-circuit gas analyzer is in normal use, the sleeve is in the raised state, and the lower edge of the sleeve is higher than the calibration chamber. This way, the sleeve will not block the airflow through the calibration chamber, ensuring that the open-circuit gas analyzer can obtain valid data.

[0020] 2. In this device, when the open-circuit gas analyzer is used in the field, the sleeve is raised. The sleeve can avoid direct sunlight and prevent the combined effect of the internal components heating up and sunlight exposure causing the body of the open-circuit gas analyzer to heat up.

[0021] 3. In this device, the sleeve can provide a certain degree of protection for the open-circuit gas analyzer, preventing foreign objects from bumping into it. When encountering extreme weather such as hail, freezing rain, or sandstorms in the field, the sleeve can be lowered to protect the upper and lower mirror surfaces of the open-circuit gas analyzer.

[0022] 4. In this device, when the open-circuit gas analyzer needs calibration and accuracy calculation, the motor is started. The motor drives the threaded rod to rotate, which in turn moves the sleeve downwards. Once the sleeve contacts the base plate, it moves into position, and the sealing mechanism seals the sleeve and the open-circuit gas analyzer. The sealed area is the calibration chamber. The standard gas tank and the inlet pipe are connected, and the solenoid valve on the inlet pipe is opened to introduce standard gas of known concentration. A range of concentration data is continuously recorded for online calibration and instrument accuracy calculation. In this invention, the sleeve not only facilitates the calibration of the open-circuit gas analyzer but also provides a certain degree of protection for the open-circuit gas analysis, effectively improving the convenience and practicality of the equipment. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the online calibration and accuracy measurement device for the open-circuit gas analyzer of the present invention;

[0025] Figure 2 This is a cross-sectional view of the present invention;

[0026] Figure 3 for Figure 2 Enlarged view of point a in the middle;

[0027] Figure 4 for Figure 2 Enlarged view of point b in the middle;

[0028] Figure 5 This is a schematic diagram of the sleeve after it has been raised according to the present invention;

[0029] The components include: 1. Open-circuit gas analyzer; 2. Sleeve; 3. Base plate; 4. Support column; 5. Protective box; 6. Threaded rod; 7. Rotating shaft; 8. Motor; 9. Inlet pipe; 10. Exhaust pipe; 11. Sealing ring one; 12. Sealing ring two; 13. Annular plate; 14. Annular groove; 15. Positioning ring; 16. Gear ring; 17. Gear; 18. Pad plate. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Reference Figure 1-5 This invention provides an online calibration and accuracy calculation device for an open-circuit gas analyzer, comprising:

[0033] Open-circuit gas analyzer 1;

[0034] Sleeve 2 is fitted around open-circuit gas analyzer 1, with a gap between sleeve 2 and open-circuit gas analyzer 1. A sealing mechanism is provided between sleeve 2 and open-circuit gas analyzer 1. A base plate 3 is fixedly connected to the bottom surface of open-circuit gas analyzer 1. Several support columns 4 are fixedly connected to the base plate 3. A protective box 5 is fixedly connected to the top of the support column 4. Sleeve 2 is slidably connected to the support column 4. A threaded rod 6 is rotatably connected between open-circuit gas analyzer 1 and protective box 5. A rotating shaft 7 is rotatably connected inside protective box 5. The rotating shaft 7 extends out of protective box 5 and is fixedly connected to threaded rod 6. A motor 8 is fixedly connected inside protective box 5. The motor 8 is drively connected to rotating shaft 7. An inlet pipe 9 and an exhaust pipe 10 are installed on sleeve 2. Solenoid valves 22 are installed on both inlet pipe 9 and exhaust pipe 10.

[0035] In this device, the open-circuit gas analyzer 1 has a calibration chamber 25, an upper mirror 23, and a lower mirror 24. When the open-circuit gas analyzer 1 is in normal use, the sleeve 2 is in the raised state, and the lower edge of the sleeve 2 is higher than the calibration chamber 25. In this embodiment, the open-circuit gas analyzer 1 is installed vertically, and the airflow passes through the calibration chamber 25 from different directions. The sleeve 2 will not block the airflow through the calibration chamber 25. When it is necessary to raise the sleeve 2, the motor 8 drives the rotating shaft 7 to rotate, the rotating shaft 7 drives the threaded rod 6 to rotate, and the threaded rod 6 drives the sleeve 2 to move upward, so that the sleeve 2 is raised.

[0036] When the open-circuit gas analyzer 1 needs to be calibrated and its accuracy calculated, the motor 8 is started. The motor 8 drives the threaded rod 6 to rotate, and the threaded rod 6 drives the sleeve 2 to move down. When the sleeve 2 contacts the base plate 3, the sleeve 2 moves down to its position. The sealing mechanism allows the sleeve 2 and the open-circuit gas analyzer 1 to be sealed. The sealed position is the calibration chamber 25. The standard gas tank and the gas inlet pipe 9 are connected. The solenoid valve 22 on the gas inlet pipe 9 is opened, and a standard gas of known concentration is introduced. A period of concentration data is continuously recorded (for example, about half an hour) for online calibration and instrument accuracy calculation (based on the Allan variance algorithm).

[0037] In this embodiment, the open-circuit gas analyzer 1 has a remote control module, and the motor 8 can be controlled by the open-circuit gas analyzer 1. The number of support pillars 4 is preferably three, and they are relatively thin so as not to affect the use of the open-circuit gas analyzer 1.

[0038] The design is further optimized. The sealing mechanism includes a first sealing ring 11, a second sealing ring 12, and an annular plate 13. The annular plate 13 is fixedly connected to the open-circuit gas analyzer 1. The first sealing ring 11 is fixedly connected to the inner edge of the sleeve 2. The second sealing ring 12 is fixedly connected to the base plate 3. An annular groove 14 is provided on the sleeve 2, and the annular groove 14 is correspondingly set with the second sealing ring 12.

[0039] When sleeve 2 falls, sealing ring 11 contacts annular plate 13, and sealing ring 12 enters annular groove 14. In this way, sleeve 2 and open-circuit gas analyzer 1 form a sealed space, sealing the space of calibration chamber 25, which facilitates online instrument calibration.

[0040] The scheme is further optimized as follows: a number of first connecting rods 19 are fixedly connected to the sleeve 2; a moving ring 20 is threadedly connected to the threaded rod 6; a number of second connecting rods 21 are fixedly connected between the first connecting rods 19 and the moving ring 20; a number of positioning rings 15 are fixedly connected to the outer wall of the sleeve 2; and the support column 4 passes through the positioning rings 15.

[0041] The inner wall of the movable ring 20 is threaded. When the threaded rod 6 rotates, the movable ring 20 will move up and down. The positioning ring 15 is used to connect the sleeve 2 and the support column 4, so that the sleeve 2 can move up and down along the support column 4.

[0042] In a further optimized design, a gear ring 16 is fixedly connected to the rotating shaft 7, and a gear 17 is fixedly connected to the output shaft of the motor 8, with the gear 17 meshing with the gear ring 16.

[0043] Motor 8 drives gear 17 to rotate, gear 17 drives gear ring 16 to rotate, thereby causing shaft 7 to rotate.

[0044] The scheme is further optimized by fixing several support rods 27 on the open-circuit gas analyzer 1, and fixing a pad 18 on the support rods 27. The threaded rod 6 is rotatably connected to the pad 18.

[0045] The gap between the pad 18 and the open-circuit gas analyzer 1 facilitates the connection of the wiring. The pad 18 is used to install the threaded rod 6.

[0046] To further optimize the design, several reinforcing rods 26 are fixedly connected between the protective box 5 and the open-circuit gas analyzer 1.

[0047] The method of using this device is as follows: when in normal use, the sleeve 2 is raised, the motor 8 drives the gear 17 to rotate, the gear 17 drives the gear ring 16 to rotate, the gear ring 16 drives the rotating shaft 7 to rotate, the rotating shaft 7 drives the threaded rod 6 to rotate, and the threaded rod 6 drives the sleeve 2 to move upward. The lower edge of the sleeve 2 is higher than the calibration chamber 25, and the airflow passes through the calibration chamber 25 from different directions.

[0048] When the open-circuit gas analyzer 1 needs to be calibrated or its accuracy calculated, the motor 8 is started. The motor 8 drives the gear 17 to rotate, the gear 17 drives the gear ring 16 to rotate, the gear ring 16 drives the rotating shaft 7 to rotate, the rotating shaft 7 drives the threaded rod 6 to rotate, and the threaded rod 6 drives the sleeve 2 to move downward. When the sleeve 2 contacts the base plate 3, the sealing ring 11 contacts the annular plate 13, and the sealing ring 12 enters the annular groove 14. In this way, the sleeve 2 and the open-circuit gas analyzer 1 form a sealed space, sealing the space of the calibration chamber 25, connecting the standard gas tank and the inlet pipe 9, opening the solenoid valve 22 on the inlet pipe 9, and introducing standard gas of known concentration. A period of concentration data is continuously recorded (for example, about half an hour) for online calibration and instrument accuracy calculation (based on the Allan variance algorithm).

[0049] During non-calibration periods, sleeve 2 is located outside the body of open-circuit gas analyzer 1, with space between sleeve 2 and open-circuit gas analyzer 1 allowing airflow for heat dissipation. Due to the requirements of flux observation methodology, the lower edge of sleeve 2 must be above the upper mirror 23; if the lower edge is below the upper mirror 23, sleeve 2 will physically obstruct the airflow through the calibration chamber, thus altering the atmospheric turbulence information under natural conditions.

[0050] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0051] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An online calibration and accuracy calculation device for an open-circuit gas analyzer, characterized in that, include: Open-circuit gas analyzer (1); A sleeve (2) is fitted over the open-circuit gas analyzer (1), with a gap between the sleeve (2) and the open-circuit gas analyzer (1). A sealing mechanism is provided between the sleeve (2) and the open-circuit gas analyzer (1). A base plate (3) is fixedly connected to the bottom surface of the open-circuit gas analyzer (1), and several support columns (4) are fixedly connected to the base plate (3). A protective box (5) is fixedly connected to the top of each support column (4). The sleeve (2) is slidably connected to the support column (4). A threaded rod (6) is rotatably connected between the instrument (1) and the protective box (5). A rotating shaft (7) is rotatably connected inside the protective box (5). The rotating shaft (7) extends out of the protective box (5) and is fixedly connected to the threaded rod (6). A motor (8) is fixedly connected inside the protective box (5). The motor (8) is driven by the rotating shaft (7). An air inlet pipe (9) and an exhaust pipe (10) are installed on the sleeve (2). A solenoid valve (22) is installed on both the air inlet pipe (9) and the exhaust pipe (10).

2. The online calibration and accuracy calculation device for an open-circuit gas analyzer according to claim 1, characterized in that: The sealing mechanism includes a first sealing ring (11), a second sealing ring (12), and an annular plate (13). The annular plate (13) is fixedly connected to the open-circuit gas analyzer (1). The first sealing ring (11) is fixedly connected to the inner edge of the sleeve (2). The second sealing ring (12) is fixedly connected to the base plate (3). An annular groove (14) is provided on the sleeve (2), and the annular groove (14) is correspondingly provided with the second sealing ring (12).

3. The online calibration and accuracy calculation device for an open-circuit gas analyzer according to claim 1, characterized in that: A plurality of first connecting rods (19) are fixedly connected to the sleeve (2), a movable ring (20) is threadedly connected to the threaded rod (6), a plurality of second connecting rods (21) are fixedly connected between the first connecting rods (19) and the movable ring (20), a plurality of positioning rings (15) are fixedly connected to the outer wall of the sleeve (2), and the support column (4) passes through the positioning rings (15).

4. The online calibration and accuracy calculation device for an open-circuit gas analyzer according to claim 1, characterized in that: A gear ring (16) is fixedly connected to the rotating shaft (7), and a gear (17) is fixedly connected to the output shaft of the motor (8). The gear (17) meshes with the gear ring (16).

5. The online calibration and accuracy calculation device for an open-circuit gas analyzer according to claim 1, characterized in that: The open-circuit gas analyzer (1) is fixedly connected to several support rods (27), and a pad (18) is fixedly connected to the support rods (27). The threaded rod (6) is rotatably connected to the pad (18).

6. The online calibration and accuracy calculation device for an open-circuit gas analyzer according to claim 1, characterized in that: Several reinforcing rods (26) are fixedly connected between the protective box (5) and the open-circuit gas analyzer (1).

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