What precautions should be taken when using a gas detector?
① Perform regular calibration and testing. Like other analytical testing instruments, toxic and harmful gas detectors adopt the relative comparison method for measurement. First, calibrate the instrument with zero gas and standard concentration gas, and store the generated standard curve inside the device. During measurement, the instrument compares the electrical signal generated by the target gas with the signal of the standard gas to calculate the accurate gas concentration value. Therefore, zeroing the instrument at any time and conducting routine calibration are indispensable to guarantee measurement accuracy. It should be noted that although most gas detectors support replaceable sensors, it does not mean one detector can be arbitrarily fitted with different sensor probes. Whenever a probe is replaced, apart from allowing sufficient activation time for the new sensor, the instrument must be recalibrated completely. In addition, it is recommended to carry out a response test with calibration gas before each use to ensure the detector can effectively perform safety protection functions.
② Guard against detection interference between different sensors. Generally, each sensor is designed for a specific target gas, yet no gas detector can achieve absolute exclusive selectivity. For this reason, when selecting a gas sensor, fully understand the interference caused by other gases to ensure precise detection of the designated gas.
③ Pay attention to the service life of various sensors. All gas sensors have a limited service life. For portable devices, LEL sensors have the longest lifespan of approximately three years; photoionization detectors can work for four years or more; electrochemical specific gas sensors have a relatively shorter service life ranging from one to two years; oxygen sensors have the shortest service life, roughly one year. The service life of electrochemical sensors depends on the evaporation of internal electrolyte. Sealing them and storing in a low-temperature environment during long-term idle periods can extend their service life to a certain extent. Fixed detectors have a larger overall structure, so their sensors enjoy a longer service cycle. Sensors shall be inspected regularly, used within their valid period as far as possible, and replaced immediately once they fail.
