Several Points to Bear in Mind When Using Gas Detectors
① Pay attention to regular calibration and testing Like other analytical instruments, toxic and harmful gas detectors adopt the relative comparison method for measurement. The instrument is calibrated with zero gas and standard-concentration gas first, and the calibration curve obtained is stored in the device. During measurement, the instrument compares the electrical signal generated by the target gas with that of the standard gas to calculate the correct gas concentration value. Therefore, zeroing the instrument at any time and performing regular calibration are indispensable to ensure accurate measurement. It should be noted that many gas detectors are equipped with replaceable sensors, but this does not mean that one detector can be fitted with different sensor probes at will. Whenever the probe is replaced, a certain sensor activation period is required, and the instrument must be recalibrated. In addition, it is recommended to carry out a response test with standard gas before use to ensure the detector can deliver effective protection.
② Pay attention to detection interference among different sensors Generally, each sensor is designed for a specific target gas, yet no gas detector is completely selective. Therefore, when selecting a gas sensor, you should fully understand the interference from other gases to ensure accurate detection of the target gas.
③ Pay attention to the service life of various sensors All gas sensors have a fixed service life. For portable instruments, LEL sensors have a longer service life of about three years; photoionization detectors can last four years or more; electrochemical sensors for specific gases have a relatively shorter lifespan of one to two years; oxygen sensors have the shortest service life, approximately one year. The service life of electrochemical sensors is limited by the drying-up of internal electrolyte. If the sensor will not be used for a long time, sealing and storing it in a low-temperature environment can extend its service life to a certain extent. Sensors of fixed detectors generally have a longer lifespan due to their larger size. Sensors shall be inspected regularly, used within their valid period, and replaced promptly once they fail.
④ Pay attention to the concentration measurement range of the detector Each toxic and harmful gas detector has a fixed measurement range. Accurate measurement can only be guaranteed within this range. Long-term measurement beyond the specified range may cause permanent damage to the sensor.
