What are some typical misconceptions about gas detectors?
1. Misunderstanding of acceptance: test with high-concentration gas
Analysis: Many customers like to test with high-concentration gas at random during acceptance. This approach is very imprecise and easy to cause damage to the instrument. The detection range of the combustible gas detector is 0~100%LEL, that is, a lower explosion limit (take methane as an example, 0~5%vol), while the lighter gas is high-purity butane, which is far beyond the detection range of the combustible gas detector !
When using lighter gas for testing, the sensor will be impacted by 2-3 times or even higher concentration, which may cause the chemical activity of the sensing element to attenuate or deactivate early, resulting in a decrease in detection accuracy and sensitivity; or burn the platinum wire, the sensor is scrapped. It should be noted that the sensor failure caused by the impact of high-concentration gas is not guaranteed by the manufacturer, and it needs to be replaced at its own expense.
Conclusion: Cautiously test the combustible gas detector with a lighter deflated! The gas detector should avoid high-concentration shocks, and the standard gas should be used to test the working conditions. The same is true for toxic gases, and high-concentration gas shocks should also be avoided.
2. Misunderstanding of model selection: organic gas is used as combustible gas detection
Analysis: Most combustible gas detectors on the market adopt the principle of catalytic combustion. The principle of catalytic combustion is to use combustible gas to produce low-temperature flameless combustion on the detection element with catalytic performance. The resistance value increases, and the change of the resistance value 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 a benzene ring structure, have relatively strong carbon chains and are difficult to break under catalytic combustion, which will lead to incomplete combustion and incomplete combustion of molecules It will accumulate on the surface of the catalytic bead, leading to the occurrence of "carbon deposition" and blocking the subsequent combustion of other molecules. When the carbon deposition reaches a certain level, the combustible gas will not be able to effectively contact the catalytic bead, which leads to insensitive or even non-existent detection. Response occurs. This is determined by the properties of the sensor itself, which is an early selection error.
Conclusion: Common benzene, alcohols, lipids, amines and other organic volatile gases are not suitable for detection by the principle of catalytic combustion, and should be detected by the principle of PID photoion. Before purchasing a gas detector, be sure to consult with the product company to avoid similar mistakes.
3. Mistakes in use: changing the use environment without authorization
Analysis: The gas detector is designed to measure the gas concentration value in the environment, and the online measurement of the hydrogen sulfide concentration in the pipeline belongs to changing the use environment. The hydrogen sulfide gas detector sensor is based on the electrochemical principle, and its electrolyte loss degree is positively correlated with the hydrogen sulfide concentration 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 only the electrolyte will be consumed when it leaks, so the service life can reach 1-2 years. There is always hydrogen sulfide in the pipeline, the electrolyte is always consumed, and the natural life is greatly shortened.
Conclusion: The gas detector is suitable for environmental detection. It is necessary to consult the manufacturer for online analysis of pipelines, and do not change the use environment without authorization.
4. Misunderstanding of maintenance: only use without maintenance
Analysis: The gas detector is a measuring instrument, and it needs to be calibrated and 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 regulations, the calibration cycle of gas detectors should not exceed one year at most, and enterprises with special measurement departments are recommended not to exceed three months. Calibration of gas detectors must be performed by professionals.
Conclusion: Buying and installing a gas detector does not guarantee normal use all the time, and it needs to be updated and maintained frequently in the later period. When there is a problem, contact the product company immediately, and do not repair it yourself. Avoid small problems causing big losses due to negligence.
