Precautions for the Operation of Gas Detectors
Toxic and hazardous gas detectors, like other analytical testing instruments, adopt the relative comparison method for measurement. The instrument is first calibrated with zero gas and gas of standard concentration, and the generated standard curve is stored inside the device. During measurement, the detector compares the electrical signal generated by the target gas with the signal from the standard gas, so as to calculate the accurate gas concentration value. Therefore, zeroing the instrument at any time and carrying out regular calibration are indispensable to ensure measurement accuracy.
It should be clarified that most gas detectors on the market are equipped with replaceable sensors, but this does not allow arbitrary fitting of different sensor probes to one single detector. Whenever a probe is replaced, sufficient activation time for the new sensor must be reserved, and the instrument shall be fully recalibrated. In addition, it is recommended to perform a response test with calibration gas before each use to ensure the detector can effectively provide safety protection.
II. Prevent Detection Interference Between Different Sensors
Generally speaking, each sensor is designed for the detection of one specific gas, yet no gas detector can achieve absolute exclusive selectivity. For this reason, when selecting a gas sensor, it is necessary to fully understand the interference effects from other gases, so as to guarantee accurate measurement of the target gas.
III. 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 service life of about three years; photoionization detectors can last four years or longer; electrochemical dedicated gas sensors have a relatively shorter lifespan of one to two years; oxygen sensors have the shortest service life of roughly one year.
The service life of electrochemical sensors is determined by the evaporation of internal electrolyte. Sealing the sensors and storing them in a low-temperature environment during long-term idle periods can properly extend their service life. Fixed detectors have a larger body structure, so their sensors generally enjoy a longer working cycle. Sensors should be inspected frequently, used within their valid period as much as possible, and replaced promptly once they fail.
