Calibration process and requirements for gas detectors
The calibration of the gas detector refers to placing the instrument in the test gas of the corresponding known concentration, and comparing the detection results of the gas detector with the gas concentration to know the accuracy of the gas detector. For example, n-hexane will burn and explode at 1.1% VOL, and when the 10% alarm is set on the hexane detector, the alarm should be triggered when the hexane concentration reaches 0.1%. For catalytic combustion sensors, this concentration is quite low. The alarm value of toxic gas is much lower than that of combustible gas. Taking chlorine gas as an example, its threshold alarm value is only 0.5ppm.
The difference between the measurement result of the re-calibrated gas detector and the measured gas concentration is generally not more than 10%, then the instrument can continue to be used without calibration. For example, if an ammonia gas detector detects 50ppm standard ammonia gas, if the measurement result of the instrument is 46ppm, then it can be considered that the detection accuracy of this ammonia gas detector is qualified without recalibration, because 46ppm is at 50±10%X50 The result is between 45~55ppm. In the same way, if the test result of this ammonia gas detector is 44ppm, then this detector needs to be recalibrated before it can be used.
The calibration of the gas detector is an important way to detect the sensitivity of the instrument and restore the accuracy of the instrument. At the same time, through testing and calibration, we can also judge whether the sensor of the gas detector has failed. Therefore, regular instrument calibration is very necessary. The general calibration is a very simple and convenient process, only two steps are required:
1. Reset the instrument to zero in "air" that does not contain the gas to be measured.
2. Put the instrument in a standard gas containing a known concentration for calibration.
For small partners in the security industry, portable detectors must be accurate and reliable, and there is no room for sloppyness. Correct and regular calibration and maintenance of the detector is an essential method, which shows how important calibration is. In fact, both detector manufacturers and national regulations also have calibration regulations, which are usually divided into two categories:
Equipment manufacturers will require regular calibration, usually within 2-6 months, to ensure that the instrument can work normally and effectively. The manufacturer recommends that qualified users, dealers or manufacturer-authorized service personnel can perform instrument calibration.
