The difference between gas detector and fixed gas detector
The oxygen concentration value measured by the gas detection instrument is 24% VOL, which is obviously beyond the standard. This phenomenon of exceeding the standard can be understood as an oxygen-enriched environment, which is not suitable for continued detection work. Because the concentration of oxygen we breathe is generally 20.9%, which is suitable for our work and survival. If the oxygen concentration in the air is lower than 19.5% (anoxic) or higher than 23.5% (oxygen-enriched), it is not an environment suitable for continuing detection operations. Therefore, as long as the oxygen concentration in the environment measured by the gas detection instrument is not lower than 19.5% VOL or higher than 23.5% VOL, you can safely carry out construction work.
Factors affecting the accuracy of oxygen detector measurement data:
Pollution of the oxygen detector: When using the oxygen detector, you must first pay attention to whether the air leaks in when connecting the sampling pipeline, and the leaked air must be blown off carefully, and try not to let a large amount of gas pass through the sensor to prolong the life of the sensor . In the purification process of the pipeline system, in order to shorten the purification time, certain methods are required. Generally, the riveting machine uses high-pressure degassing and low-flow blowing alternately to quickly purify the pipeline.
Selection of pipe material: pipe material and surface roughness will also affect the change of oxygen content in the sample gas. It is generally not suitable to use plastic pipes, rubber pipes, etc. as connecting pipes. Copper or stainless steel tubes are usually used, and polished stainless steel tubes must be used for ultra-trace analysis (refers to <0.1ppm).
Leakage self-inspection of oxygen detectors: Gas detectors must be strictly leak tested before they are first used. The oxygen gas analyzer can only obtain correct data results under tight and leak-free conditions. Any loose connection points, solder joints, valves, etc. will cause the gas in the air to infiltrate into the pipeline and the oxygen analyzer, resulting in inaccurate measurement data.
Simplification and cleanliness of the gas circuit system of the oxygen detector: trace analysis requires that all kinds of pipe fittings on the gas circuit, chamfering machine valves, meter heads, etc. dead angles on the sample gas must be effectively eliminated. Therefore, the manual pipe bender should simplify the air circuit system as much as possible, and choose connectors with small dead angles. And avoid using equipment such as water seals, oil seals and wax seals to prevent dissolved oxygen from escaping and causing pollution. It is also necessary to avoid adding purification equipment that is easy to cause pollution on the pipeline leading from the sample gas to the inlet of the oxygen analyzer. This is the only way to ensure that the system is clean and the resulting data is correct.
