What circumstances need to be taken into consideration when calibrating flammable gas detectors?
Before the calibration of the combustible gas detector, it should be ensured that there is no combustible gas in the surrounding environment of the combustible gas detector. If there is combustible gas, the rainproof cover should be removed first, and a certain amount of clean air should be filled in, and then the sample gas should be continuously introduced. , to ensure the accuracy of the calibration.
In principle, the calibration of combustible gas detectors should use the standard gas that has been certified by metrology and matches the gas to be detected.
When the measured gas is a hydrocarbon mixture, isobutane is selected as the sample gas, followed by propane.
For non-hydrocarbon mixtures or hydrocarbon mixtures with a large difference in heat generated during combustion of gases with lower explosive concentration, as a last resort, easily available and stable single-component fuels such as butane, isobutane, and propane can be used as samples. gas. At this time, the range of the alarm must be adjusted according to a certain detection signal conversion relationship.
Fault Analysis of Combustible Gas Detector
Combustible gas detectors are detectors installed and used in industrial and civil buildings that respond to single or multiple combustible gas concentrations. There are two types of combustible gas detectors that are most used in daily life: catalytic combustible gas detectors and semiconductor combustible gas detectors. Restaurants, guesthouses, home workshops and other places that use gas, natural gas, and liquefied petroleum gas mainly use semiconductor-type flammable gas detectors, and industrial places that emit flammable gas and flammable steam mainly use catalytic-type flammable gas detectors.
Possible failures and cause analysis of combustible gas detectors:
1. There is no display when the combustible gas detector is turned on. Cause of failure: Membrane switch failure; battery lead broken: The battery voltage is seriously insufficient.
2. There is only a minus sign when the combustible gas detector is turned on, and there is no count when you press the "voltage" button. Cause of failure: The regulated power supply is faulty or its output side is short-circuited.
3. There is only a decimal point when the combustible gas detector is turned on. Cause of failure: There is a damaged ring in the sensing element; or a component in the bridge circuit is desoldered.
4. The combustible gas detector does not alarm if it exceeds the limit. Cause of failure: The ring of the ringer is damaged: the alarm circuit is disconnected.
5. The accuracy of the combustible gas detector cannot be adjusted to the standard gas sample. Cause of failure: the explosion-proof cover is seriously dusty; the sensor is aging.
