How to calibrate fixed gas detectors?

January 16, 2023
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If the host readings are high or low, it is necessary to check whether the value displayed by the field instrument is consistent with the value displayed by the controller first. If the same, the detector needs to be calibrated; if not, not only the detector needs to be calibrated, but also the detector and the controller need to be calibrated for the zero point and range of the current value.

The unstable reading of the host may be caused by the detector not being calibrated well, first restore the factory settings to see, and then check whether there is a loose sensor, and at the same time, the gas detector needs to be calibrated again.

According to the lower explosion limit of each detection gas, we need to target the calibration.
The next MIC600 fixed combustible gas detector is an example, for you to sort out the calibration process of gas detectors.

Before calibration, we need to prepare: zero standard gas, range standard gas, calibration pressure reducing valve (including flow meter), supporting calibration cover, and calibration hose.
Connect the standard gas cylinder, calibration pressure-reducing valve, hose, calibration cover, and detector closely in turn, open the valve and ventilate in turn, and wait for the detector value to be stable before calibration.
Safety measures should be taken before calibration, with remote control without opening the lid operation.

In order to ensure accuracy, it is recommended to use pure nitrogen gas for zero calibration.
Slowly open the cylinder valve, adjust the flow meter knob to 0.5L/min, ventilate and start calibration after the value is stable.

Select the specified concentration of standard gas for range calibration.
Slowly open the cylinder valve, adjust the flowmeter knob to 0.5L/min, and start calibration after the value stabilizes. After calibration, cut off the valve of the standard gas cylinder in time to prevent the explosion or poisoning caused by gas leakage.


Notes on calibration

Gas detectors should pay attention to the following matters when calibrating.

I. Calibration environment conditions. The error of the gas detector in calibration mainly comes from the calibration environment. Therefore, the detector should be installed as far as possible in a place without wind, dust, water, shock, vibration, corrosion, and electromagnetic interference.

Second, calibration flow control. As the size of the gas detector flow rate may directly affect the accuracy of the calibration results, therefore, the flow rate needs to be controlled. The flow rate is too large, or too small, which will affect the calibration results.

Third, the calibration hood for calibration. In the calibration of the combustible, toxic gas detector, will use the calibration hood, and each manufacturer has its own special calibration hood, in the calibration, it is best to use the original production calibration hood is better, and the calibration results will be more accurate. In addition, to ensure the accuracy of detection, gas detectors are calibrated at least once every 3-6 months.

It can be seen that the gas detector as a measuring instrument, its regular maintenance, and calibration is a key link to ensure the safety of the site.