A Brief Look at Factors Affecting Gas Detector Operation
① Pay attention to detection interference between different sensors
Generally speaking, each sensor is designed for one specific target gas, yet no gas detector can achieve absolute specificity. Therefore, when selecting a gas sensor, you should fully understand interference from other gases, so as to ensure accurate measurement of the target gas.
② Like other analytical instruments, toxic and hazardous gas detectors perform measurement based on the relative comparison method. The instrument is calibrated with zero‑gas and standard‑concentration gas, and the calibration curve is stored inside the device. During measurement, the instrument compares the electrical signal generated by the sample gas with that of the standard gas, and calculates the accurate gas‑concentration value. Consequently, zeroing at all times and regular calibration are indispensable for reliable readings.
It should be noted that many gas detectors support replaceable sensors, but this does not mean one detector can freely work with any sensor probe. Whenever you replace a probe, apart from the required sensor warm‑up period, the instrument must be recalibrated. In addition, it is recommended to perform a response test with standard calibration gas before use, so that the detector can provide effective protection.
③ Pay attention to the service life of different sensors
All gas sensors have a limited service life. For portable instruments, the LEL sensor usually lasts about three years; photoionization detectors can serve four years or longer; 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 depends on the evaporation of internal electrolyte. Sealing and storing them in a low‑temperature environment when not in use for long periods can extend service life. Sensors should be inspected regularly and used within their valid period. Replace sensors promptly once they fail.
④ Pay attention to the measuring range of the detector
Every toxic‑hazardous gas detector has a fixed measuring range. Accurate measurement can only be guaranteed within this range. Long‑term measurement beyond the specified range may cause permanent damage to the sensor. For instance, an LEL sensor may be burnt out if exposed to an environment over 100 %LEL. Toxic‑gas sensors will also be damaged under long‑term high‑concentration exposure. Therefore, when a fixed detector triggers an over‑range alarm, shut down the measuring circuit immediately to protect the sensor.
