As we all know, the gas detector is currently the 1 gas detection instrument we use to detect changes in the concentration of harmful gases in the job site. However, there are many friends, when using, because of the lack of cognition, there are some misunderstandings about the gas detector, which leads to the failure of the gas detector, which not only has a serious impact on our work, but also poses a serious threat to our health. So what are the pitfalls in the use of gas detector ? The following is an introduction by Yi Yuntian:

The use of gas detectors is prone to the following misconceptions:

1. acceptance errors: test with high concentration gas

Analysis: Many customers like to test with high concentration gas at will during acceptance, which is very loose and easy to cause instrument damage.The detection range of combustible gas detector is 0~100 LEL, that is, a lower explosive limit (taking methane as an example, 0 ~ 5% vol), while lighter gas is high purity butane, far exceeding the detection range of combustible gas detector!

when lighter gas is used for testing, the sensor will be impacted by 2~3 times or even higher concentration, which will cause the chemical activity of the sensing element to attenuate or deactivate early, resulting in the decrease of detection accuracy and sensitivity. In severe cases, the platinum wire is burned, the sensor is discarded. It should be noted that the sensor failure caused by the impact of high concentration gas is not guaranteed by the manufacturer and needs to be replaced at its own expense.

Conclusion: Do not use lighter deflation to test the combustible gas detector! Gas detector should avoid high concentration impact, check the working condition should use standard gas for testing. Toxic gas in the same way, should also avoid high concentration gas impact.

2. misconceptions: organic gas when combustible gas detection

analysis: most combustible gas detectors on the market adopt the principle of catalytic combustion, which uses combustible gas to generate low-temperature flameless combustion on detection elements with catalytic performance, the heat of combustion causes the temperature of the element to increase, so that the resistance of the element increases, and the change of its resistance is detected by the Wheatstone bridge to achieve the purpose of detecting the concentration of combustible gas.

Although in principle, as long as it can burn and release heat, it can be Detected, it is often said that catalytic combustion sensors can theoretically measure any combustible gas.

However, catalytic combustion sensors are not suitable for measuring long-chain alkanes, such as gasoline, diesel, and aromatics with high flash points. Benzene, toluene, xylene and other compounds with more than 5 carbon atoms, especially hydrocarbon compounds with benzene ring structure, the carbon chain is relatively strong, and it is difficult to break under catalytic combustion, which will lead to incomplete combustion, and incomplete combustion Molecules will accumulate on the surface of the catalytic bead, leading to the occurrence of "carbon deposit" phenomenon, blocking the subsequent combustion of other molecules, when the carbon deposit reaches a certain level, the combustible gas will not be able to effectively contact with the catalytic beads, which leads to insensitive detection or even no response. This is determined by the properties of the sensor itself and belongs to the early selection error.

Conclusion: Common organic volatile gases such as benzene, alcohols, lipids and amines are not suitable for detection by catalytic combustion principle, and PID photoion principle should be used for detection. Before purchasing a gas detector, you must consult with the product company to avoid similar errors.

3. misconceptions: unauthorized change of use environment

Analysis: The gas detector is designed to measure the gas concentration value in the environment, and online measurement of hydrogen sulfide concentration in pipelines belongs to the change of use environment.The sensor of hydrogen sulfide gas detector is an electrochemical principle, and its electrolyte loss degree is positively related to the concentration of hydrogen sulfide in the environment. The more hydrogen sulfide content, the faster the electrolyte consumption and the shorter the service life. The concentration of hydrogen sulfide in the normal environment is 0, and the electrolyte will be consumed only when it leaks, so the life span can reach 1-2 years. Hydrogen sulfide has always existed in the pipeline, the electrolyte has been consumed, and the natural life is greatly shortened.

Conclusion: The gas detector is suitable for environmental testing. For online analysis of pipelines, the manufacturer should be consulted. Do not change the use environment without authorization.

4. maintenance errors: use only without maintenance

Analysis: Gas detector is a measuring instrument, and it needs to be calibrated regularly to ensure the accuracy of its detection. Any gas detector will drift after long-term use. If it is not calibrated in time, the error will become larger and larger, causing potential safety hazards. According to the regulations, the maximum fixed period of the gas detector shall not exceed one year, and the enterprise with special metering department recommends no more than 3 months. The calibration of the gas detector needs to be carried out by professionals.

conclusion: the purchase and installation of a gas detector cannot always guarantee normal use. later, it should be updated and maintained frequently. if there is a problem, contact the product company immediately and do not repair it yourself. Avoid small problems that lead to big losses due to negligence.

In summary, the use of gas detectors is prone to some misunderstandings. In order to ensure the use, we must pay attention to these misunderstandings when using them.