Performance test device and method for open-path combustible gas detector

Abstract

The invention discloses an open path combustible gas detector performance test device and method, and belongs to the technical field of open path combustible gas detector tests.The device comprises a bottom plate, a sliding table, a gas chamber fixing frame, a standard gas chamber and a gas chamber driving frame, the sliding table is arranged on the bottom plate, and a supporting plate is fixed to a sliding part of the sliding table; two air chamber fixing frames are arranged on the supporting plate in parallel, the standard air chamber is arranged on the two air chamber fixing frames, an air chamber driving frame is arranged between the two air chamber fixing frames, and the air chamber driving frame is located on the lower portion of the standard air chamber and drives the standard air chamber to rotate. According to the invention, comprehensive and accurate test and calibration of the open-path combustible gas detector are realized.

Description

Technical Field

[0001] This invention relates to the field of open-path combustible gas detector testing technology, specifically to an open-path combustible gas detector performance testing device and method. Background Technology

[0002] Currently, combustible gas detectors used in explosive gas environments are mainly categorized into alarm detectors, aspirating detectors, automatic aspirating detectors, continuous operation detectors, diffusion detectors, fixed detectors, portable detectors, mobile detectors, and gas detection transmitters. All of these types of detectors operate on a point-to-point detection basis, meaning the equipment must be installed at the specific point to be monitored. Existing oil and petrochemical plants are typically large-scale facilities requiring numerous monitoring points, necessitating the installation of a large number of combustible gas detectors. Open-path detectors, however, can achieve a breakthrough in gas detection technology by measuring combustible gas along the optical path point-to-point, moving from point-to-line detection. However, the accuracy, stability, and speed of this technology currently lack standardized and scientific testing and calibration methods. Therefore, there is an urgent need for a performance testing device and method for open-path combustible gas detectors. Summary of the Invention

[0003] In view of this, the present invention addresses the shortcomings of the prior art by providing an open-path combustible gas detector performance testing device and method.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an open path combustible gas detector performance testing device, including a base plate, a slide table, a gas chamber fixing frame, a standard gas chamber and a gas chamber drive frame. The slide table is provided on the base plate, and a support plate is fixed on the sliding part of the slide table. Two gas chamber fixing frames are arranged in parallel on the support plate. The standard gas chamber is set on the two gas chamber fixing frames. The gas chamber drive frame is set between the two gas chamber fixing frames. The gas chamber drive frame is located below the standard gas chamber and drives the standard gas chamber to rotate.

[0005] Furthermore, the standard gas chamber includes a cylindrical tube with filters at both ends. There are four standard gas chambers, which store combustible gases with concentrations of 10%, 25%, 50%, and 75%, respectively.

[0006] Furthermore, the air chamber fixing frame includes a base, an annular support frame, and rollers. The annular support frame is installed on the upper part of the base, and three rollers are evenly distributed on the inner side of the annular support frame. An adjustment handle is installed on the outer side of the annular support frame corresponding to the position of the rollers.

[0007] Furthermore, the air chamber drive frame includes a gantry frame, with a drive wheel mounted on top of the gantry frame. One end of the drive wheel is connected to a drive motor, and the surface of the drive wheel contacts a standard air chamber.

[0008] Furthermore, the annular support frame consists of two semicircular rings, one end of which is hinged and the other end is connected by a connector.

[0009] Furthermore, a horizontal linear module and a vertical linear module are set on the base plate, and a barrier cover or louver is installed on the moving block of the horizontal linear module and the moving block of the vertical linear module.

[0010] Furthermore, it also includes a direct sunlight test component, which includes a stainless steel cylinder, a reflective plane mirror, a ball-head clamp, and a fixed steel frame. Optical glass is installed at both ends of the stainless steel cylinder. A light shield is connected to the end of the stainless steel cylinder closest to the receiving end of the test sample. An iris fixture is inclinedly installed on the upper right side of the stainless steel cylinder. The iris fixture includes an inclined branch pipe connected to the top surface of the stainless steel cylinder and a convex lens installed at the upper end of the inclined branch pipe. The reflective plane mirror is connected to one end of the fixed steel frame through the ball-head clamp and is located above the iris fixture.

[0011] Another object of the present invention is to provide a performance testing method for an open-path combustible gas detector, implemented based on the open-path combustible gas detector performance testing apparatus described above, comprising: Calibration test of open path combustible gas detector: Using a flow-rate gas distribution system, four standard gas chambers with gas concentrations of 10%, 25%, 50%, and 75% are prepared using the displacement method. The four standard gas chambers are then rapidly rotated and simultaneously moved into the optical paths of the transmitter and receiver of the open path detector, in order of increasing concentration. Each standard gas chamber is tested three times. The difference between the measured value and the standard gas chamber concentration value should not exceed ±10% of the measurement range, or not exceed 20% of the standard gas chamber concentration value, whichever is larger. Stability test of open path combustible gas detector: The open-path combustible gas detector was first run in ambient air for 8 weeks. During this period, the gas chamber was filled with 50% concentration of test gas every week and at the end of the test. The chamber was placed in the optical path for 3 minutes and the readings were recorded. The difference between the measured value and the nominal value should not be greater than ±10% of the measurement range or ±20% of the measured value, whichever is larger. Alarm reliability test of open path combustible gas detector: Turn on the power to the test sample and allow it to operate normally before zeroing it. Set the alarm point to 41.5% LEL.m. After the test sample has been working for 30 seconds, a standard air chamber with 50% LEL is installed on the air chamber holder. The chamber is then moved into the optical path while being rotated rapidly and held for 30 seconds. The test sample is recorded as to whether it alarms. After that, the chamber is rotated out of the optical path. Keep the test sample working normally for another 30 seconds, then move the 50% LEL standard air chamber into the optical path while rotating rapidly, and maintain this position for 30 seconds. Record whether the test sample alarms, and then rotate it out of the optical path. Keep the test sample working normally for another 30 seconds, then move the 50% LEL standard air chamber into the optical path while rotating rapidly, and maintain this position for 30 seconds. Record whether the test sample alarms, and then rotate it out of the optical path. Water vapor interference test for open path combustible gas detectors: Turn on the power supply of the test sample. After it is working normally, zero it. After working normally for 30 minutes, set the alarm point to 24% LEL.m. First, place the water vapor chamber filled with dry and clean air into the optical path to ensure its stable operation. Then, install the standard chamber with 15% LEL on the chamber holder and move it into the optical path while rotating it rapidly. Record whether the test sample alarms and record the display value after stabilization. Then, rotate it out of the optical path. Replace and install the standard 25% LEL air chamber on the air chamber holder, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. Next, place the water vapor chamber with a local pressure of 50 kPa into the optical path to keep it working stably. Install a standard chamber with 15% LEL on the chamber fixture and move it into the optical path while rotating it rapidly. Record whether the test sample alarms and record the display value after stabilization. Then rotate it out of the optical path. Replace and install a standard 25% LEL gas chamber on the gas chamber fixture, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. After the experiment is completed, organize the experimental data and calculate the difference between the measured value and the nominal value. The difference between the measured value and the nominal value should not be greater than ±10% of the measurement range, or not greater than ±20% of the measured value, and take the larger of the two. Vibration test of open path combustible gas detector: Turn on the power supply of the test sample and allow it to work normally. Then zero the power supply and allow it to work normally for 30 minutes. Set the alarm point to 20% LEL.m. Install a standard air chamber with 50% LEL on the air chamber holder, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. Fix the test specimen on the vibration table, turn on the power, and adjust the vibration tester. When the vibration frequency is between 10Hz and 30Hz, the amplitude is 1.0mm; or when the vibration frequency is between 30Hz and 150Hz, the peak acceleration is 19.6m / s². 2 Choose one of the vibration modes and vibrate for 1 hour in each of the X, Y, and Z directions; After the vibration ends, install and turn on the power supply of the test sample, and after it is working normally, zero it and preset 20% LEL.m as the alarm point; then install a standard air chamber with 50% LEL on the air chamber fixing frame, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. After the experiment is completed, organize the experimental data and calculate the difference between the measured value and the nominal value. The difference between the measured value and the nominal value should not be greater than ±10% of the measurement range, or not greater than ±20% of the measured value, whichever is greater. Drop performance test of open path combustible gas detectors: All test specimens should be fixed on the drop test platform. Portable equipment should be dropped from a height of 1 m onto the concrete surface while in operation; movable equipment weighing less than 5 kg should be dropped from a height of 0.3 m onto the concrete surface while not in operation; other movable equipment should be dropped from a height of 0.1 m onto the concrete surface. This procedure should be performed three times, each time dropping from a different side, with movable equipment from its normal moving position. Turn on the power supply of the test sample and allow it to operate normally. Then zero the power supply and allow it to operate normally for 30 minutes. Set the alarm point to 50% LEL.m. Install a standard air chamber with 50% LEL on the air chamber fixture, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. Response time test of open path combustible gas detector: Turn on the power supply to the test sample, and after it is in normal working order, zero it. Install a standard air cell with 50% LEL on the air cell holder, and move it into the optical path while rotating it rapidly. Start timing and record the time taken when the displayed value is 45% LEL. It should not exceed 10 seconds. Then rotate it out of the optical path. Keep the test sample working normally, and preset the alarm point to 41.5% LEL.m; while rapidly rotating the standard gas chamber of 50% LEL, move it into the optical path and start timing. Record the time from the start of the alarm for the test sample, which should not exceed 10 seconds, and then rotate it out of the optical path. Minimum operating time test of open path combustible gas detector: Turn on the power supply to the test sample, and after it is in normal working order, zero it. Install a standard air cell with 50% LEL on the air cell holder, and start timing after it is rapidly rotated and moved into the optical path. When the displayed value is 45% LEL, quickly rotate the air cell out of the optical path and record the time taken for the displayed value to reach 5% LEL. The time should not exceed 30 seconds. Voltage fluctuation test of open path combustible gas detector: Turn on the power supply to the test sample to the rated voltage, and after it is working normally, adjust it to zero. Install a standard air cell with 50% LEL on the air cell fixture, and move it into the optical path while rotating it rapidly. Record the display value after it stabilizes, and then rotate the air cell out of the optical path. The display value should not be greater than ±5% of the measurement range, or not greater than ±10% of the measured value, whichever is greater. Adjust the power supply of the test sample to 115% of the rated voltage and observe whether the equipment can operate normally. Install a standard air chamber with 50% LEL on the air chamber fixture and move it into the optical path while rotating it rapidly. Record the display value after stabilization and rotate the air chamber out of the optical path. The display value should not be greater than ±5% of the measurement range or ±10% of the measured value, whichever is greater. Power interruption and transient tests on open-path combustible gas detectors: Turn on the power supply of the test sample to the rated voltage, and after it is in normal working order, zero it. Set the alarm point to 20% LEL.m concentration. Use a DC voltage drop generator to interrupt the power supply to the test sample for 10ms, with a 10s interval between each interruption, repeat ten times, and record whether the device shows any shielding, fault or alarm signals. After the equipment has been powered off 10 times, a standard air chamber with 50% LEL is installed on the air chamber holder. While rotating rapidly, the chamber is moved horizontally into the optical path, and the displayed value is recorded after stabilization. The air chamber is then rotated out of the optical path; the displayed value should not exceed ±2% of the standard value. Adjust the power supply of the test sample to 110% of the rated voltage. After the equipment stabilizes, use a DC voltage drop generator to reduce the power supply of the test sample to 85% of the rated voltage within 10ms. Record whether the equipment exhibits shielding, fault, or alarm signals. After the transient test is interrupted, the test sample is adjusted to the rated voltage. After stabilization, the standard gas cell with 50% LEL is moved into the optical path while rotating rapidly. The display value after stabilization is recorded. The gas cell is then rotated out of the optical path. The display value should not exceed ±2% of the standard value.

[0012] Beam blocking failure test of open path combustible gas detector: Turn on the power supply to the test sample to the rated voltage. After it is working normally, zero the instrument. The alarm point is 10% LEL·m concentration in the sample measurement range. An opaque louver fixture is installed 50 mm away from the transmitter in the optical path. The louver is then inserted into the optical path at a uniform speed of (10±5) cm / s from left to right, from right to left, from top to bottom, and from bottom to top until the beam is completely blocked. Then, the opaque louver is completely removed at the same speed. Record whether there is any signal blocking or shielding when the beam is completely blocked during the entire process, and whether the louver returns to normal after it is completely removed. Next, adjust the equipment to normal operating condition, install a standard air cell with 50% LEL on the air cell fixture, and move it into the optical path while rotating it rapidly, and record the display value after it stabilizes. Next, after rotating the standard air chamber out, use the louver fixture to quickly cut the louver into the light path from left to right until the beam is completely blocked; then, quickly rotate the standard air chamber with 50% LEL into the light path, and then quickly remove the louver and start timing, recording the time when the display value reaches ±10%, which should not exceed 30 seconds. Partial shielding test of open-path combustible gas detectors: Turn on the power supply to the test sample to the rated voltage. After it is working normally, zero the instrument. The alarm point is 10% LEL·m concentration in the sample measurement range. Install a blocking cover 50mm away from the receiver in the optical path. Insert the blocking cover into the optical path at a uniform speed of 10±5cm / s from top to bottom, from left to right, from right to left, and from bottom to top until the beam is blocked by 50%. Then, remove the blocking cover completely at the same speed. Record whether there is any blocking or shielding signal during the whole process. Record the displayed value when the beam is blocked by 50% each time. The difference between the displayed value and the nominal value should be within ±10% of the measurement range or within ±20% of the measured value, whichever is greater. Long-distance operation test of open-path combustible gas detector: Install the test sample at the maximum working distance, turn on the power supply of the test sample to the rated voltage, and adjust it to zero after it is working normally. Install a blocking cover 50mm away from the receiver in the optical path, and cut into the optical path from top to bottom at a uniform speed of (10±5)cm / s until the beam is blocked by 90%. Record whether the device generates shielding, fault signals or false alarms. Install a standard air cell with 50% LEL on the air cell holder, and move it into the optical path while rotating it rapidly. Record the displayed value after it stabilizes. The difference between the value and the nominal value should be within ±10% of the measurement range, or within ±20% of the measured value, whichever is greater.

[0013] Direct sunlight test of open-path combustible gas detector: When selecting an outdoor site with sufficient sunlight, and using a wide-band sub-spectral radiometer to measure the light intensity at the entrance of the iris recognition fixture to be (800±50)W / m2, turn on the power supply of the test sample to the rated voltage, and after it is working normally, zero it; Adjust the reflective plane mirror to fix the angle of solar radiation reflection relative to the optical axis of the test sample at +10°, +3°, -3°, and -10° respectively (+10°, +3°, -3°, and -10° are the angles between the reflected solar rays and the optical axis of the test sample, respectively, 10° above the vertical plane, 3° to the left of the horizontal plane, 3° to the right of the horizontal plane, and 10° below the vertical plane). Each time, the reading is recorded in a gas cell with a concentration of 50% of the measurement range until it stabilizes. Record the stable display value at each tilt angle and record whether any shielding, fault, or alarm signals are generated. After the experiment is completed, the experimental data should be compiled. The difference between the displayed value and the nominal value should not be greater than ±10% of the measurement range, or not greater than ±20% of the measured value, whichever is greater.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention relates to an open-path combustible gas detector performance testing device. By fabricating multiple standard gas chambers, the standard gas chambers rotate rapidly under the action of a gas chamber fixing frame and a gas chamber driving frame, and enter the optical path of the combustible gas detector under test under the action of a sliding table. In this way, the momentary obstruction when the gas chamber enters and exits will not cause an "optical path obstruction" state, minimizing the impact on the equipment, thereby reducing the impact of beam reflection, distortion and attenuation as much as possible, and minimizing the impact on equipment calibration.

[0015] This invention provides a performance testing method for open-path combustible gas detectors. By eliminating the influence of factors such as optical path obstruction and temperature sensitivity, and reducing the effects of beam reflection, distortion, and attenuation, the method scientifically and effectively performs calibration and testing on open-path combustible gas detectors in sequence, including calibration curves, stability, alarm reliability, water vapor interference, vibration, drop performance, response time, shortest operating time, voltage fluctuation test, power interruption and transient, electromagnetic compatibility, beam blockage fault, partial shading, long-distance operation test, and direct sunlight test. This method achieves comprehensive and accurate calibration and testing of open-path combustible gas detectors. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the standard air chamber in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the air chamber fixing frame in an embodiment of the present invention; Figure 4 This is a partial structural schematic diagram of an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the solar direct sunlight test component in an embodiment of the present invention; Figure 6 This is a partial cross-sectional view of the solar direct sunlight test component in an embodiment of the present invention; In the diagram: 1-Transmitter, 2-Receiver, 3-Base plate, 4-Electric slide, 5-Cavity mounting bracket, 6-Standard air chamber, 7-Cavity drive bracket, 8-Support plate, 9-Horizontal linear module, 10-Vertical linear module, 11-Louvre, 12-Stainless steel cylinder, 13-Reflective plane mirror, 14-Ball head fixing clamp, 15-Fixed steel frame, 16-Light shield, 17-Inclined branch pipe, 18-Convex lens, 51-Base, 52-Annular support frame, 53-Roller, 54-Adjusting handle, 61-Cylindrical tube, 62-Filter, 63-Fixed plate, 64-Cover plate, 65-Inflation valve, 71-Gantry frame, 72-Drive wheel. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0018] Example 1: Refer to Figure 1 An open-path combustible gas detector performance testing device is located between the transmitter 1 and receiver 2 of the open-path combustible gas detector. It includes a base plate 3, an electric slide 4, a gas chamber fixing frame 5, a standard gas chamber 6, and a gas chamber drive frame 7. The electric slide 4 is installed on the base plate 3. A support plate 8 is fixed on the sliding part of the electric slide 4. Two gas chamber fixing frames 5 are arranged in parallel on the support plate 8. The standard gas chamber 6 is installed on the two gas chamber fixing frames 5. The gas chamber drive frame 7 is located between the two gas chamber fixing frames 5. The gas chamber drive frame 7 is located below the standard gas chamber 6 and drives the standard gas chamber 6 to rotate.

[0019] Reference Figure 2 The standard gas chamber 6 includes a cylindrical tube 61 made of PC material. Filters 62 are installed at both ends of the cylindrical tube 61. The filters 62 are fixed to the ends of the cylindrical tube 61 by a fixing plate 63 and a cover plate 64. There are four standard gas chambers 6, which store combustible gases (such as methane, hydrogen, acetylene, ethylene, etc.) with gas concentrations of 10%, 25%, 50%, and 75%, respectively. An inflation valve 65 is located at the bottom of each standard gas chamber 6.

[0020] Reference Figure 3The air chamber fixing frame 5 includes a base 51, an annular support frame 52, and rollers 53. The annular support frame 52 is installed on the upper part of the base 51. Three rollers 53 are evenly distributed on the inner side of the annular support frame 52. Adjustment handles 54 are installed on the outer side of the annular support frame 52 corresponding to the positions of the rollers 53, for adjusting the extension and retraction of the rollers 53, so as to fix and rotate the standard air chamber. The annular support frame 52 is composed of upper and lower semicircular rings. One end of the two semicircular rings is hinged, and the other end is connected by a connector.

[0021] Reference Figure 4 The air chamber drive frame 7 includes a gantry frame 71, with a drive wheel 72 mounted on the top of the gantry frame 71. One end of the drive wheel 72 is connected to a drive motor, and the surface of the drive wheel 72 is in contact with the standard air chamber 6.

[0022] Reference Figure 1 A horizontal linear module 9 and a vertical linear module 10 are set on the base plate 3. A barrier cover or louver 11 is installed on the moving block of the horizontal linear module 9 and the moving block of the vertical linear module 10.

[0023] The method for testing the performance of an open-path combustible gas detector according to an embodiment of the present invention includes: I. Calibration Test of Open Path Combustible Gas Detector: Using a flow-rate gas distribution system, four standard gas chambers with gas concentrations of 10%, 25%, 50%, and 75% are prepared using the displacement method. The four standard gas chambers are then rapidly rotated and simultaneously moved into the optical paths of the transmitter and receiver of the open path detector, in order of increasing concentration. Each standard gas chamber is tested three times. The difference between the measured value and the standard gas chamber concentration value should not exceed ±10% of the measurement range, or not exceed 20% of the standard gas chamber concentration value, and the larger value should be taken.

[0024] II. Stability test of open-path combustible gas detector: The open-path combustible gas detector was first run in ambient air for 8 weeks. During this period, the gas chamber was filled with 50% concentration of test gas every week and at the end of the test. The chamber was placed in the optical path for 3 minutes and the readings were recorded. The difference between the measured value and the nominal value should not be greater than ±10% of the measurement range or ±20% of the measured value, whichever is larger. III. Alarm reliability test of open-path combustible gas detectors: Turn on the power to the test sample and allow it to operate normally before zeroing it. Set the alarm point to 41.5% LEL.m. After the test sample has been working for 30 seconds, a standard air chamber with 50% LEL is installed on the air chamber holder. The chamber is then moved into the optical path while being rotated rapidly and held for 30 seconds. The test sample is recorded as to whether it alarms. After that, the chamber is rotated out of the optical path. Keep the test sample working normally for another 30 seconds, then move the 50% LEL standard air chamber into the optical path while rotating rapidly, and maintain this position for 30 seconds. Record whether the test sample alarms, and then rotate it out of the optical path. Keep the test sample working normally for another 30 seconds, then move the 50% LEL standard air chamber into the optical path while rotating rapidly, and maintain this position for 30 seconds. Record whether the test sample alarms, then rotate it out of the optical path.

[0025] IV. Water vapor interference test for open-path combustible gas detectors: Turn on the power supply of the test sample. After it is working normally, zero it. After working normally for 30 minutes, set the alarm point to 24% LEL.m. First, place the water vapor chamber filled with dry and clean air into the optical path to ensure its stable operation. Then, install the standard chamber with 15% LEL on the chamber holder and move it into the optical path while rotating it rapidly. Record whether the test sample alarms and record the display value after stabilization. Then, rotate it out of the optical path. Replace and install the standard 25% LEL air chamber on the air chamber holder, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. Next, place the water vapor chamber with a local pressure of 50 kPa into the optical path to keep it working stably. Install a standard chamber with 15% LEL on the chamber fixture and move it into the optical path while rotating it rapidly. Record whether the test sample alarms and record the display value after stabilization. Then rotate it out of the optical path. Replace and install a standard 25% LEL gas chamber on the gas chamber fixture, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. After the experiment is completed, organize the experimental data and calculate the difference between the measured value and the nominal value. The difference between the measured value and the nominal value should not be greater than ±10% of the measurement range, or not greater than ±20% of the measured value, and take the larger of the two.

[0026] V. Vibration test of open-path combustible gas detector: Turn on the power supply of the test sample and allow it to work normally. Then zero the power supply and allow it to work normally for 30 minutes. Set the alarm point to 20% LEL.m. Install a standard air chamber with 50% LEL on the air chamber holder, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. Fix the test specimen on the vibration table, turn on the power, and adjust the vibration tester. When the vibration frequency is between 10Hz and 30Hz, the amplitude is 1.0mm; or when the vibration frequency is between 30Hz and 150Hz, the peak acceleration is 19.6m / s².2 Select one of the vibration modes and vibrate for 1 hour in each of the X, Y, and Z directions; repeat this operation once for test samples where the sensor and control unit are far apart. After the vibration ends, install and turn on the power supply of the test sample, and after it is working normally, zero it and preset 20% LEL.m as the alarm point; then install a standard air chamber with 50% LEL on the air chamber fixing frame, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. After the experiment is completed, organize the experimental data and calculate the difference between the measured value and the nominal value. The difference between the measured value and the nominal value should not be greater than ±10% of the measurement range, or not greater than ±20% of the measured value, whichever is greater.

[0027] VI. Drop performance test of open path combustible gas detectors: All test specimens should be fixed on the drop test platform. Portable equipment should be dropped from a height of 1 m onto the concrete surface while in operation; movable equipment weighing less than 5 kg should be dropped from a height of 0.3 m onto the concrete surface while not in operation; other movable equipment should be dropped from a height of 0.1 m onto the concrete surface. This procedure should be performed three times, each time dropping from a different side, with movable equipment from its normal moving position. Turn on the power supply of the test sample and allow it to operate normally. Then zero the power supply and allow it to operate normally for 30 minutes. Set the alarm point to 50% LEL.m. Install a standard air chamber with 50% LEL on the air chamber fixture, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path.

[0028] VII. Response time test of open path combustible gas detector: Turn on the power supply to the test sample, and after it is in normal working order, zero it. Install a standard air cell with 50% LEL on the air cell holder, and move it into the optical path while rotating it rapidly. Start timing and record the time taken when the displayed value is 45% LEL. It should not exceed 10 seconds. Then rotate it out of the optical path. Keep the test sample working normally, and preset the alarm point to 41.5% LEL.m; while rapidly rotating the standard gas chamber of 50% LEL, move it into the optical path and start timing. Record the time from the start of the alarm for the test sample, which should not exceed 10 seconds, and then rotate it out of the optical path.

[0029] 8. Minimum operating time test for open-path combustible gas detectors: Turn on the power supply to the test sample, and after it is in normal working order, zero it. Install a standard air cell with 50% LEL on the air cell holder, and start timing after it is rapidly rotated and moved into the optical path. When the displayed value is 45% LEL, quickly rotate the air cell out of the optical path and record the time taken for the displayed value to reach 5% LEL. The time should not exceed 30 seconds. IX. Voltage fluctuation test of open-path combustible gas detector: Turn on the power supply to the test sample to the rated voltage, and after it is working normally, adjust it to zero. Install a standard air cell with 50% LEL on the air cell fixture, and move it into the optical path while rotating it rapidly. Record the display value after it stabilizes, and then rotate the air cell out of the optical path. The display value should not be greater than ±5% of the measurement range, or not greater than ±10% of the measured value, whichever is greater. Adjust the power supply of the test sample to 115% of the rated voltage and observe whether the equipment can operate normally. Install a standard air chamber with 50% LEL on the air chamber fixture and move it into the optical path while rotating it rapidly. Record the display value after stabilization and rotate the air chamber out of the optical path. The display value should not be greater than ±5% of the measurement range or ±10% of the measured value, whichever is greater.

[0030] 10. Power interruption and transient test of open-path combustible gas detectors: Turn on the power supply of the test sample to the rated voltage, and after it is in normal working order, zero it. Set the alarm point to 20% LEL.m concentration. Use a DC voltage drop generator to interrupt the power supply to the test sample for 10ms, with a 10s interval between each interruption, repeat ten times, and record whether the device shows any shielding, fault or alarm signals. After the equipment has been powered off 10 times, a standard air chamber with 50% LEL is installed on the air chamber holder. While rotating rapidly, the chamber is moved horizontally into the optical path, and the displayed value is recorded after stabilization. The air chamber is then rotated out of the optical path; the displayed value should not exceed ±2% of the standard value. Adjust the power supply of the test sample to 110% of the rated voltage. After the equipment stabilizes, use a DC voltage drop generator to reduce the power supply of the test sample to 85% of the rated voltage within 10ms. Record whether the equipment exhibits shielding, fault, or alarm signals. After the transient test is interrupted, the test sample is adjusted to the rated voltage. After stabilization, the standard gas cell with 50% LEL is moved into the optical path while rotating rapidly. The display value after stabilization is recorded. The gas cell is then rotated out of the optical path. The display value should not exceed ±2% of the standard value.

[0031] XI. Beam blocking fault test of open path combustible gas detector: Turn on the power supply to the test sample to the rated voltage. After it is working normally, zero the instrument. The alarm point is 10% LEL·m concentration in the sample measurement range. An opaque louver fixture is installed 50 mm away from the transmitter in the optical path. The louver is then inserted into the optical path at a uniform speed of (10±5) cm / s from left to right, from right to left, from top to bottom, and from bottom to top until the beam is completely blocked. Then, the opaque louver is completely removed at the same speed. Record whether there is any signal blocking or shielding when the beam is completely blocked during the entire process, and whether the louver returns to normal after it is completely removed. Next, adjust the equipment to normal operating condition, install a standard air cell with 50% LEL on the air cell fixture, and move it into the optical path while rotating it rapidly, and record the display value after it stabilizes. Next, after rotating the standard air chamber out, use the louver fixture to quickly insert the louver into the light path from left to right until the beam is completely blocked. Then, install the standard air chamber with 50% LEL and quickly rotate it into the light path. After quickly removing the louver, start timing and record the time when the displayed value is ±10%, which should not exceed 30 seconds.

[0032] 12. Partial shielding test for open-path combustible gas detectors: Turn on the power supply to the test sample to the rated voltage. After it is working normally, zero the instrument. The alarm point is 10% LEL·m concentration in the sample measurement range. Install a blocking cover 50mm away from the receiver in the optical path. Insert the blocking cover into the optical path at a uniform speed of 10±5cm / s from top to bottom, from left to right, from right to left, and from bottom to top until the beam is blocked by 50%. Then, remove the blocking cover completely at the same speed. Record whether there is any blocking or shielding signal during the entire process. Record the displayed value when the beam is blocked by 50% each time. The difference between the displayed value and the nominal value should be within ±10% of the measurement range or within ±20% of the measured value, whichever is greater.

[0033] Thirteen, Long-distance operation test of open-path combustible gas detectors: Install the test sample at the maximum working distance, turn on the power supply of the test sample to the rated voltage, and adjust it to zero after it is working normally. Install a blocking cover 50mm away from the receiver in the optical path, and cut into the optical path from top to bottom at a uniform speed of (10±5)cm / s until the beam is blocked by 90%. Record whether the device generates shielding, fault signals or false alarms. Install a standard air cell with 50% LEL on the air cell holder, and move it into the optical path while rotating it rapidly. Record the displayed value after it stabilizes. The difference between the value and the nominal value should be within ±10% of the measurement range, or within ±20% of the measured value, whichever is greater.

[0034] Example 2: Refer to Figure 5 , Figure 6The performance testing device for open-path combustible gas detectors in this embodiment of the invention, based on Embodiment 1, further includes a direct sunlight testing component. This component comprises a stainless steel cylinder 12, a reflective plane mirror 13, a ball-head clamp 14, and a fixed steel frame 15. Optical glass is installed at both ends of the stainless steel cylinder 12. A light shield 16 is connected to the end of the stainless steel cylinder 12 closest to the receiving end of the test sample. An iris fixture is inclinedly installed on the upper right side of the stainless steel cylinder 12. The iris fixture includes an inclined branch pipe 17 connected to the top surface of the stainless steel cylinder 12 and a convex lens 18 installed at the upper end of the inclined branch pipe 17. The reflective plane mirror 13 is connected to one end of the fixed steel frame 15 via the ball-head clamp 14, and is located above the iris fixture. During the test, the stainless steel cylinder can be fixed on the gas chamber fixing frame but does not rotate.

[0035] The test method for the open-path combustible gas detector performance test device of this invention, based on Embodiment 1, further includes a direct sunlight test of the open-path combustible gas detector: When selecting an outdoor site with sufficient sunlight, and using a wide-band sub-spectral radiometer to measure the light intensity at the entrance of the iris recognition fixture to be (800±50)W / m2, turn on the power supply of the test sample to the rated voltage, and after it is working normally, zero it; Adjust the reflective plane mirror to fix the angle of solar radiation reflection relative to the optical axis of the test sample at +10°, +3°, -3° and -10° respectively. (In this embodiment, +10°, +3°, -3° and -10° are the angles between the reflected solar rays and the optical axis of the test sample, respectively, 10° above the vertical plane, 3° to the left of the horizontal plane, 3° to the right of the horizontal plane and 10° below the vertical plane). Each time, the reading is stabilized in a gas chamber at 50% of the measurement range concentration. Record the stable display value at each tilt angle and record whether shielding, fault or alarm signals are generated. After the experiment is completed, the experimental data should be compiled. The difference between the displayed value and the nominal value should not be greater than ±10% of the measurement range, or not greater than ±20% of the measured value, whichever is greater.

[0036] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the claims of the present invention.

Claims

1. A performance testing device for an open-path combustible gas detector, characterized in that: It includes a base plate, a slide table, a chamber fixing frame, a standard chamber, and a chamber drive frame. The slide table is set on the base plate, and a support plate is fixed on the sliding part of the slide table. Two chamber fixing frames are set in parallel on the support plate. The standard chamber is set on the two chamber fixing frames. The chamber drive frame is set between the two chamber fixing frames. The chamber drive frame is located below the standard chamber and drives the standard chamber to rotate.

2. The performance testing device for open-path combustible gas detectors according to claim 1, characterized in that: The standard gas chamber consists of a cylindrical tube with filters at both ends. There are four standard gas chambers, which store combustible gases with concentrations of 10%, 25%, 50%, and 75%, respectively.

3. The performance testing device for open-path combustible gas detectors according to claim 2, characterized in that: The air chamber fixing frame includes a base, an annular support frame, and rollers. The annular support frame is set on the upper part of the base. Three rollers are evenly distributed on the inner side of the annular support frame. An adjustment handle is set on the outer side of the annular support frame corresponding to the position of the rollers.

4. The performance testing device for open-path combustible gas detectors according to claim 3, characterized in that: The air chamber drive frame includes a gantry frame, with a drive wheel at the top of the gantry frame. One end of the drive wheel is connected to a drive motor, and the surface of the drive wheel is in contact with a standard air chamber.

5. The performance testing device for open-path combustible gas detectors according to claim 4, characterized in that: The ring support frame consists of two semicircular rings, one at one end and the other at the other.

6. The performance testing device for open-path combustible gas detectors according to claim 5, characterized in that: A horizontal linear module and a vertical linear module are set on the base plate. Both the moving blocks of the horizontal linear module and the moving blocks of the vertical linear module are equipped with baffles or louvers.

7. The performance testing device for open-path combustible gas detectors according to claim 6, characterized in that: It also includes a direct sunlight test component, which consists of a stainless steel cylinder, a reflective plane mirror, a ball-head clamp, and a fixed steel frame. Optical glass is installed at both ends of the stainless steel cylinder. A light shield is connected to the end of the stainless steel cylinder closest to the receiving end of the test sample. An iris fixture is inclinedly installed on the upper right side of the stainless steel cylinder. The iris fixture includes an inclined branch pipe connected to the top surface of the stainless steel cylinder and a convex lens installed at the upper end of the inclined branch pipe. The reflective plane mirror is connected to one end of the fixed steel frame through the ball-head clamp and is located above the iris fixture.

8. A method for testing the performance of an open-path combustible gas detector, implemented based on the open-path combustible gas detector performance testing apparatus as described in any one of claims 1-5, characterized in that, include: Calibration test of open path combustible gas detector: Using a flow-rate gas distribution system, four standard gas chambers with gas concentrations of 10%, 25%, 50%, and 75% are prepared using the displacement method. The four standard gas chambers are then rapidly rotated and simultaneously moved into the optical paths of the transmitter and receiver of the open path detector, in order of increasing concentration. Each standard gas chamber is tested three times. The difference between the measured value and the standard gas chamber concentration value should not exceed ±10% of the measurement range, or not exceed 20% of the standard gas chamber concentration value, whichever is larger. Stability test of open path combustible gas detector: The open-path combustible gas detector was first run in ambient air for 8 weeks. During this period, the gas chamber was filled with 50% concentration of test gas every week and at the end of the test. The chamber was placed in the optical path for 3 minutes and the readings were recorded. The difference between the measured value and the nominal value should not be greater than ±10% of the measurement range or ±20% of the measured value, whichever is larger. Alarm reliability test of open path combustible gas detector: Turn on the power to the test sample and allow it to operate normally before zeroing it. Set the alarm point to 41.5% LEL.m. After the test sample has been working for 30 seconds, a standard air chamber with 50% LEL is installed on the air chamber holder. The chamber is then moved into the optical path while being rotated rapidly and held for 30 seconds. The test sample is recorded as to whether it alarms. After that, the chamber is rotated out of the optical path. Keep the test sample working normally for another 30 seconds, then move the 50% LEL standard air chamber into the optical path while rotating rapidly, and maintain this position for 30 seconds. Record whether the test sample alarms, and then rotate it out of the optical path. Keep the test sample working normally for another 30 seconds, then move the 50% LEL standard air chamber into the optical path while rotating rapidly, and maintain this position for 30 seconds. Record whether the test sample alarms, and then rotate it out of the optical path. Water vapor interference test for open path combustible gas detectors: Turn on the power supply of the test sample. After it is working normally, zero it. After working normally for 30 minutes, set the alarm point to 24% LEL.m. First, place the water vapor chamber filled with dry and clean air into the optical path to ensure its stable operation. Then, install the standard chamber with 15% LEL on the chamber holder and move it into the optical path while rotating it rapidly. Record whether the test sample alarms and record the display value after stabilization. Then, rotate it out of the optical path. Replace and install the standard 25% LEL air chamber on the air chamber holder, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. Next, place the water vapor chamber with a local pressure of 50 kPa into the optical path to keep it working stably. Install a standard chamber with 15% LEL on the chamber fixture and move it into the optical path while rotating it rapidly. Record whether the test sample alarms and record the display value after stabilization. Then rotate it out of the optical path. Replace and install a standard 25% LEL gas chamber on the gas chamber fixture, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. After the experiment is completed, organize the experimental data and calculate the difference between the measured value and the nominal value. The difference between the measured value and the nominal value should not be greater than ±10% of the measurement range, or not greater than ±20% of the measured value, and take the larger of the two. Vibration test of open path combustible gas detector: Turn on the power supply of the test sample and allow it to work normally. Then zero the power supply and allow it to work normally for 30 minutes. Set the alarm point to 20% LEL.m. Install a standard air chamber with 50% LEL on the air chamber holder, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. Fix the test specimen on the vibration table, turn on the power, and adjust the vibration tester. When the vibration frequency is between 10Hz and 30Hz, the amplitude is 1.0mm; or when the vibration frequency is between 30Hz and 150Hz, the peak acceleration is 19.6m / s². 2 Choose one of the vibration modes and vibrate for 1 hour in each of the X, Y, and Z directions; After the vibration ends, install and turn on the power supply of the test sample, and after it is working normally, zero it and preset 20% LEL.m as the alarm point; then install a standard air chamber with 50% LEL on the air chamber fixing frame, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. After the experiment is completed, organize the experimental data and calculate the difference between the measured value and the nominal value. The difference between the measured value and the nominal value should not be greater than ±10% of the measurement range, or not greater than ±20% of the measured value, whichever is greater. Drop performance test of open path combustible gas detectors: All test specimens should be fixed on the drop test platform. Portable equipment should be dropped from a height of 1 m onto the concrete surface while in operation; movable equipment weighing less than 5 kg should be dropped from a height of 0.3 m onto the concrete surface while not in operation; other movable equipment should be dropped from a height of 0.1 m onto the concrete surface. This procedure should be performed three times, each time dropping from a different side, with movable equipment from its normal moving position. Turn on the power supply of the test sample and allow it to operate normally. Then zero the power supply and allow it to operate normally for 30 minutes. Set the alarm point to 50% LEL.m. Install a standard air chamber with 50% LEL on the air chamber fixture, and move it into the optical path while rotating it rapidly. Record whether the test sample alarms, and record the display value after stabilization. Then rotate it out of the optical path. Response time test of open path combustible gas detector: Turn on the power supply to the test sample, and after it is in normal working order, zero it. Install a standard air cell with 50% LEL on the air cell holder, and move it into the optical path while rotating it rapidly. Start timing and record the time taken when the displayed value is 45% LEL. It should not exceed 10 seconds. Then rotate it out of the optical path. Keep the test sample working normally, and preset the alarm point to 41.5% LEL.m; while rapidly rotating the standard gas chamber of 50% LEL, move it into the optical path and start timing. Record the time from the start of the alarm for the test sample, which should not exceed 10 seconds, and then rotate it out of the optical path. Minimum operating time test of open path combustible gas detector: Turn on the power supply to the test sample, and after it is in normal working order, zero it. Install a standard air cell with 50% LEL on the air cell holder, and start timing after it is rapidly rotated and moved into the optical path. When the displayed value is 45% LEL, quickly rotate the air cell out of the optical path and record the time taken for the displayed value to reach 5% LEL. The time should not exceed 30 seconds. Voltage fluctuation test of open path combustible gas detector: Turn on the power supply to the test sample to the rated voltage, and after it is working normally, adjust it to zero. Install a standard air cell with 50% LEL on the air cell fixture, and move it into the optical path while rotating it rapidly. Record the display value after it stabilizes, and then rotate the air cell out of the optical path. The display value should not be greater than ±5% of the measurement range, or not greater than ±10% of the measured value, whichever is greater. Adjust the power supply of the test sample to 115% of the rated voltage and observe whether the equipment can operate normally. Install a standard air chamber with 50% LEL on the air chamber fixture and move it into the optical path while rotating it rapidly. Record the display value after stabilization and rotate the air chamber out of the optical path. The display value should not be greater than ±5% of the measurement range or ±10% of the measured value, whichever is greater. Power interruption and transient tests on open-path combustible gas detectors: Turn on the power supply of the test sample to the rated voltage, and after it is in normal working order, zero it. Set the alarm point to 20% LEL.m concentration. Use a DC voltage drop generator to interrupt the power supply to the test sample for 10ms, with a 10s interval between each interruption, repeat ten times, and record whether the device shows any shielding, fault or alarm signals. After the equipment has been powered off 10 times, a standard air chamber with 50% LEL is installed on the air chamber holder. While rotating rapidly, the chamber is moved horizontally into the optical path, and the displayed value is recorded after stabilization. The air chamber is then rotated out of the optical path; the displayed value should not exceed ±2% of the standard value. Adjust the power supply of the test sample to 110% of the rated voltage. After the equipment stabilizes, use a DC voltage drop generator to reduce the power supply of the test sample to 85% of the rated voltage within 10ms. Record whether the equipment exhibits shielding, fault, or alarm signals. After the transient test is interrupted, the test sample is adjusted to the rated voltage. After stabilization, the standard gas cell with 50% LEL is moved into the optical path while rotating rapidly. The display value after stabilization is recorded. The gas cell is then rotated out of the optical path. The display value should not exceed ±2% of the standard value.

9. A method for testing the performance of an open-path combustible gas detector, implemented based on the open-path combustible gas detector performance testing apparatus as described in claim 6, characterized in that, include: Beam blocking failure test of open path combustible gas detector: Turn on the power supply to the test sample to the rated voltage. After it is working normally, zero the instrument. The alarm point is 10% LEL·m concentration in the sample measurement range. An opaque louver fixture is installed 50 mm away from the transmitter in the optical path. The louver is then inserted into the optical path at a uniform speed of (10±5) cm / s from left to right, from right to left, from top to bottom, and from bottom to top until the beam is completely blocked. Then, the opaque louver is completely removed at the same speed. Record whether there is any signal blocking or shielding when the beam is completely blocked during the entire process, and whether the louver returns to normal after it is completely removed. Next, adjust the equipment to normal operating condition, install a standard air cell with 50% LEL on the air cell fixture, and move it into the optical path while rotating it rapidly, and record the display value after it stabilizes. Next, after rotating the standard air chamber out, use the louver fixture to quickly cut the louver into the light path from left to right until the beam is completely blocked; then, quickly rotate the standard air chamber with 50% LEL into the light path, and then quickly remove the louver and start timing, recording the time when the display value reaches ±10%, which should not exceed 30 seconds. Partial shielding test of open-path combustible gas detectors: Turn on the power supply to the test sample to the rated voltage. After it is working normally, zero the instrument. The alarm point is 10% LEL·m concentration in the sample measurement range. Install a blocking cover 50mm away from the receiver in the optical path. Insert the blocking cover into the optical path at a uniform speed of 10±5cm / s from top to bottom, from left to right, from right to left, and from bottom to top until the beam is blocked by 50%. Then, remove the blocking cover completely at the same speed. Record whether there is any blocking or shielding signal during the whole process. Record the displayed value when the beam is blocked by 50% each time. The difference between the displayed value and the nominal value should be within ±10% of the measurement range or within ±20% of the measured value, whichever is greater. Long-distance operation test of open-path combustible gas detector: Install the test sample at the maximum working distance, turn on the power supply of the test sample to the rated voltage, and adjust it to zero after it is working normally. Install a blocking cover 50mm away from the receiver in the optical path, and cut into the optical path from top to bottom at a uniform speed of (10±5)cm / s until the beam is blocked by 90%. Record whether the device generates shielding, fault signals or false alarms. Install a standard air cell with 50% LEL on the air cell holder, and move it into the optical path while rotating it rapidly. Record the displayed value after it stabilizes. The difference between the value and the nominal value should be within ±10% of the measurement range, or within ±20% of the measured value, whichever is greater.

10. A method for testing the performance of an open-path combustible gas detector, implemented based on the open-path combustible gas detector performance testing apparatus as described in claim 7, characterized in that, include: Direct sunlight test of open-path combustible gas detector: When selecting an outdoor site with sufficient sunlight, and using a wide-band sub-spectral radiometer to measure the light intensity at the entrance of the iris recognition fixture to be (800±50)W / m2, turn on the power supply of the test sample to the rated voltage, and after it is working normally, zero it; Adjust the reflective plane mirror to fix the angle of solar radiation reflection and the optical axis of the test sample at +10°, +3°, -3° and -10° in sequence. Each time, in a gas cell with a concentration of 50% of the measurement range, until the reading stabilizes, record the stable display value at each tilt angle, and record whether shielding, fault or alarm signals are generated. After the experiment is completed, the experimental data should be compiled. The difference between the displayed value and the nominal value should not be greater than ±10% of the measurement range, or not greater than ±20% of the measured value, whichever is greater.

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