What are the types, common problems, and troubleshooting of methane sensors

Apr 13,2023

Methane sensor, as the name implies, is a sensor that can detect the concentration of methane gas, which can be divided into various types according to its principle:

1. Infrared methane sensor (infrared principle);

2. Laser methane sensor (diode laser principle);

3. Optical interference methane sensor (optical principle);

4. Catalytic combustion methane sensor (chemical principle);

5. Electrocatalytic methane sensor (chemical principle);

In addition, combustible gas sensors and thermal conductivity gas sensors can also be used to detect methane.

Generally speaking, in order to ensure the safety of coal mine work, methane sensors need to be calibrated before use. So how should it be adjusted?

Methane sensor calibration steps before use:

1. Check whether the appearance of the methane sensor is complete, and clean the surface and air chamber dust.

2. Connect the methane sensor to the regulated power supply, frequency meter (or substation), and preheat for 10 minutes.

3. Adjust the zero point of the instrument in fresh air, and the zero value range is controlled at 0.00-0.03% CH4.

4. According to the gas flow rate required by the user manual, calibrate the gas entering the gas chamber with 2.0% CH4, adjust the accuracy of the methane sensor so that the displayed value is consistent with the calibration gas concentration value, and then repeat the adjustment until it is accurate. During the basic error measurement, do not make adjustments again.

5. Basic error measurement. According to the flow rate during the calibration period, the gas is calibrated until the gas chamber is fed with 0.5, 1.0, 3.0% CH4 for about 90 seconds, and each gas is fed into the calibration for three times, and the average value is calculated, and the basic error is calculated by the average value and Standard values are calculated.

6. At the same time, observe whether the measurement alarm point, power failure point, light alarm, etc. are normal during each ventilation.

7. Sound and light alarm test. When an alarm occurs, the warning light should flash, and make sure the sound level meter is one meter away from the buzzer, measure the source of the sound and measure the sound level.

8. Measure the response time. Use a stopwatch to measure the start and end times of the 3.0% CH4 calibration gas, showing the value rising from zero to 90% of the large display.

In addition, in the process of daily use of the methane sensor, we may encounter some minor faults. So, what are the common problems and troubleshooting methods of the methane sensor?

1. Leakage

When an air leak occurs, it is time to check for damaged hoses, an unconnected or leaking pressure regulator can cause a severe air leak, simply replace the damaged hose, or reconnect or repair the pressure regulator.

2. Power off the switch

When the main power switch loses power, please check whether the power socket is damaged, whether the fuse is burned out, etc., and repair it.

3. The display does not display or the buttons and data are displayed incorrectly.

Most of them are caused by circuit faults, and the methane analyzer should be repaired in time after the fault is found.

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