1. Acceptance misunderstanding: test with high concentration gas
Analysis: Many customers like to test high-concentration gases at will during acceptance. This approach is very imprecise and can easily 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, it is 0~5%vol), and 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 to 3 times or even higher concentrations, which will cause early attenuation or deactivation of the chemical activity of the sensing element, resulting in decreased detection accuracy and sensitivity; 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 needs to be replaced at their own expense.
Conclusion: Do not use a lighter to deflate to test a combustible gas detector! The gas detector should avoid high-concentration shock, and check the working condition with standard gas for testing. The same is true for toxic gases, and the impact of high-concentration gases should also be avoided.
2. Misunderstanding of model selection: organic gas is detected as combustible gas
Analysis: Most of the combustible gas detectors on the market use the principle of catalytic combustion. The principle of catalytic combustion is to use combustible gas to generate low-temperature flameless combustion on the detection element with catalytic properties. The resistance value increases, and the change of the resistance value is detected by the Wheatstone bridge, so as 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 aromatic hydrocarbons 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 of molecules It will accumulate on the surface of the catalytic beads, resulting in 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 beads, which results in insensitive or even non-sensitive detection. A response phenomenon occurs. This is determined by the properties of the sensor itself, which is an early selection error.
Conclusion: The common organic volatile gases such as benzene, alcohols, lipids, and amines are not suitable for detection by the principle of catalytic combustion, but should be detected by the principle of PID photoionization. Be sure to consult with the product company before purchasing a gas detector to avoid similar mistakes.
3. Misunderstandings in use: changing the use environment without authorization
Analysis: The gas detector is designed to measure the gas concentration in the environment, and the online measurement of the hydrogen sulfide concentration in the pipeline belongs to changing the use environment. The sensor of the hydrogen sulfide gas detector is based on an electrochemical principle, and the loss of the electrolyte is positively correlated with the concentration of hydrogen sulfide in the environment. The more hydrogen sulfide content, the faster the electrolyte consumption and the shorter the life. The concentration of hydrogen sulfide in the normal environment is 0, and the electrolyte will only be consumed when it leaks, so the life span 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. For on-line analysis of pipelines, the manufacturer should be consulted, and the use environment should not be changed without authorization.
Fourth, maintenance misunderstanding: only use without maintenance
Analysis: The gas detector is a measuring instrument and 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 increase and cause safety hazards. According to the regulations, the fixed period of the gas detector shall not exceed one year at the longest, and it is recommended that the enterprise with a special measurement department should not exceed three months. The calibration of gas detectors needs to be performed by professionals.
Conclusion: Buying and installing a gas detector does not always guarantee normal use. It needs to be updated and maintained frequently in the later stage. If there is a problem, please contact the product company immediately, and do not repair it yourself. Avoid small mistakes that lead to big losses due to negligence.
