As a detection instrument, the gas detector needs to be calibrated regularly, usually once every six months or one year.When the gas detector leaves the factory, the manufacturer will calibrate the detector, but why do we need to calibrate it regularly?
Electrochemical sensors and catalytic combustion sensors will gradually change due to the influence of certain substances in the environment during use, or the influence of strong changes in temperature and humidity, so it is necessary to calibrate the gas detector regularly. In order to ensure that the error of the gas detector detection result does not exceed the normal range, it is also necessary to calibrate it frequently. In this way, the accuracy of the gas detector detection result can be determined. In addition, regular calibration can also find problems with the sensor and whether a new sensor needs to be replaced.
The equipment required for calibration are:
Gas detector, standard gas cylinder, flow meter, pressure valve (generally the standard gas cylinder is equipped with a pressure valve to control the flow). The calibration of gas detector is divided into two steps:
1. Zeroing, that is, calibrating the zero point
Place the gas detector in normal air, or pass 99.99% pure nitrogen, and after the value stabilizes, enter the zeroing menu and set it to 0. Oxygen is special, and the concentration of oxygen in the air is 20.9%vol, and CO2 is about 6%vol~8%vol.
2. Calibration: Generally, at least one point or 2-3 points need to be calibrated. For example, a 0-200ppm H2S detector can be calibrated once with a 100ppm H2S standard gas cylinder, or three times with 50ppm, 100ppm, and 150ppm standard gas cylinders. The steps are as follows:
Pass the standard gas through the gas detector for half a minute or one minute, wait for the displayed value to stabilize, and set it to the concentration of the corresponding standard gas.
For the fixed digital gas detector produced by our company Xi'an Huafan Technology Co., Ltd., the 3 points calibration steps are as follows:
F-P1 ~ F-P3 gas calibration (entering 1234 password when entering the menu)
Supports 3-point calibration. First enter 1 concentration standard gas, wait for the value to stabilize, enter F~P1, press OK, enter the standard gas concentration, press OK to display the AD value, and then press OK to display "good" after successful calibration, calibration "FAIL" is displayed if it fails.
Remove the standard gas, wait for the value to drop to normal, then pass in other concentration standard gas, enter F~P2/P3, the operation is the same as above. (Oxygen transmitter is generally calibrated to 20.9 in clean air)
1. If the number of calibration gas is less than 3, you need to input the value of other calibration points as 0000, and the parameters of other calibration points will be cleared.
2. If you have performed a 3-point calibration before for the gas detector, it is recommended to input all the calibration point values as 0000 and clear all the calibration parameters, otherwise the displayed value may be incorrect during calibration.