In the process of long-term use of the four-in-one gas detector, various reasons will cause the instrument to drift, resulting in excessive error accuracy, so that the measurement results will be inaccurate, and in severe cases, it will even affect the safety warning function of the four-in-one gas detector. Therefore, in order to ensure the safety of use, we need to verify the four-in-one gas detector. So do you know what is the main verification method of the four-in-one gas detector?

4-in -1 gas detector main verification methods:

1. Alarm function

The four-in-one gas detector is supplied with a gas standard substance with a concentration about 1.5 times the alarm setting value, observe whether the sound, light or vibration alarm function of the four-in-one gas detector is normal, and record the alarm concentration value displayed by the four-in-one gas detector, which is the alarm action value.

2. Indication error

to the four-in-one gas detector, three gas standard substances with different concentration states are introduced respectively, and record the measurement results of the four-in-one gas detector respectively. Repeat the detection steps of each concentration three times, and calculate the relative error and absolute error of the four-in-one gas detector by using the formula to calculate the difference between the average value of the detection results of the four-in-one gas detector and the actual gas concentration.

The concentration of the gas reference substance introduced for the indication error verification is respectively:

Ex: 10%, 40%, 60% of full scale gas reference material

H2S: 20%, 50%, 80% of full scale gas reference material

O2: 20%, 50%, 80% of full scale gas reference material

CO:1.5 times the four-in-one gas detector alarm (lower limit) setting value, 30% upper limit of measurement range and 70% upper limit of measurement range gas standard substance

3, response time

First introduce zero gas to calibrate the zero point of the four-in-one gas detector; secondly, the four-in-one gas detector is connected to a certain range of concentration (Ex: 40% of full scale; H2S: 50% of full scale; O2: 80% of full scale; CO:70% of the upper limit of the measurement range) of the gas standard substance, after the four-in-one gas detector is stable, the gas will be removed; Re-feeding zero gas to stabilize the four-in-one gas detector; then pass into the above-mentioned concentration of gas standard substances, with a stopwatch record from the pass to the four-in-one gas detector stable display of 90% of the above-mentioned concentration of the time, repeated three times to take the average is the response time of the four-in-one gas detector.

4. Repeatability

4-in -1 gas detector after preheating and stabilization, adjust the zero point of the four-in-one gas detector with zero gas, and introduce a certain range of concentration (Ex: 40% of full scale; H2S: 50% of full scale; O2: 80% of full scale; CO:70% upper limit of measurement range) gas standard substance, record stable measurement data, and repeat the operation 6 times, the relative standard deviation of a single measurement is the repeatability of the four-in-one gas detector.

to sum up, it is the main verification method of the four-in-one gas detector. in the verification process, we can refer to the national standards of the metrological verification regulations for the corresponding types of gases, so as to maintain the linearity and accuracy of measurement more stably.