In modern society, combustible gas as a clean energy has been widely used in all aspects. But its flammable and explosive characteristics will also bring no small disaster, so we must pay attention to the leakage of gas in the process of using combustible gas to prevent the concentration of combustible gas from exceeding the standard.
A powerful tool to prevent gas explosion is the gas detection and alarm instrument, which can effectively detect the current gas concentration in the air, and send an audible and visual alarm signal when the concentration exceeds the standard to remind users to take safety measures, so as to avoid major safety accidents. The alarm value of the general gas alarm is divided into two levels.
The fixed combustible gas monitor is usually equipped with two lower limit alarm levels: "10%LEL" is a first-level alarm point, "25%LEL" is a second-level alarm point. Portable gas detector usually has a lower level alarm point "25%LEL" and an upper level alarm point "50%LEL". Call point. The lower explosive limit LEL and upper explosive limit LEL are important indicators of combustible gas detector.
The following is a simple example to analyze the alarm point setting and the upper and lower limits of the explosion:
For example, the lower explosive limit of methane is "5%" volume ratio (that is, when the volume content of methane in the air reaches 5%, the lower explosive limit is reached), and the "5%" volume ratio is equal to one hundred, so that the "5%" volume ratio corresponds to "100%LEL", that is, when the detector value reaches the "100%LEL" alarm point, This corresponds to a methane content of "5%" by volume ratio.
When the value reaches the "25%LEL" alarm point, the methane content is equivalent to "1.25%" volume ratio at this time.
Therefore, users do not have to worry about the flammable gas detector alarm will be immediately dangerous, it is still a certain distance from the explosion. Take appropriate measures immediately, such as opening the exhaust fan or cutting off some valves or opening the spray system, and the danger of explosion will not appear.
All in all, the reason why the gas detector is set up multiple alarm points is to give the user sufficient time to escape or solve the problem, because only from the real possibility of dangerous lower explosive limit there is a large gap to alarm, so as to play the role of alarm warning.