Are there gas detectors that can measure concentrations above the explosion limit?
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Ordinary combustible gas probes operate in the 0-100% LEL (Lower Explosive Limit) range. Taking methane as an example, its explosive limit is 5%-15%, so the range of such probes for detecting methane is from 0-5% in terms of volume percentage concentration. Now the question is: in the range of 15%-100% volume percentage concentration of methane, is there any probe other than a concentration analyzer that can detect it? Is there anything based on electrochemical principles?
It’s simple; I know that there are combustible gas sensors that can detect combustible gases in the range of 0-100% Vol
Thank you, I found it. As long as it’s 0-100% VOL, it will work; I plan to use one based on infrared technology.
Thank you, I found it. As long as it’s 0-100% VOL, it will work; I plan to use one based on infrared technology.
I have a question: According to GB/T50493, in section 3.0.2, when the concentration of flammable gases in the leaking gas may reach the alarm set value, a flammable gas detector should be installed. The alarm value is set at ≤25% LEL for the first-level alarm of combustible gases. The LEL for methane is 5%, so the alarm setting should be 1.25%. The current volume concentration of methane in the gas mixture is 19.54% – is it necessary to install a methane combustible gas alarm? How can this be determined?
From a safety perspective, although concentrations above the upper limit will not cause an explosion, they can still burn in the presence of an open flame or lead to asphyxiation. Therefore, monitoring is still necessary, but it is done using different types of concentration meters rather than those used for ordinary flammable gases.
It is to determine whether an explosive gas environment could form in the surroundings after a mixture of gases leaks, rather than relying directly on the proportion of methane in the confined space.
Electrochemical probes can be used to detect high concentrations of methane on a volume basis, and they are capable of providing accurate measurement values. Additionally, optical sensors can also detect high concentrations of methane by volume; they use ultraviolet spectroscopic imaging technology to measure the volume percentage of methane, but their measurement accuracy is limited by interference from the optical system.