Combustible gas detector principle, what are the installation requirements

Update:29-11-2019
Summary:

  I. Overview of Combustible Gas Detectors Combust […]

 

I. Overview of Combustible Gas Detectors

Combustible gas detector. It is a common alarm device. When a flammable gas leaks in the industrial environment and daily life environment, it will alarm when it reaches the concentration of flammable gas. It can be widely used in gas stations, gas stations, and gas Pipelines, municipal fire protection and other places where flammable gas leaks occur, and long-term uninterrupted monitoring of these places will be carried out. When it exceeds the preset dangerous concentration, it will enter an alarm state, which can activate the connected audible and visual alarms, warning Operators around the site. In order to remind the staff to take safety measures, and drive the exhaust, cut-off, and sprinkler systems to prevent explosions, fires, and poisoning accidents, thereby ensuring safe production.
Twenty-two, common detection gases

It is mainly used to detect flammable gases in the air, such as hydrogen (H2), methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), ethylene (C2H4), propylene (C3H6), Butene (C4H8), acetylene (C2H2), propyne (C3H4), butyne (C4H6), phosphine (PH3), etc.

III. Principle of Combustible Gas Detector

Here are two main points. One is a combustible gas detector of the catalytic combustion sensor type, and the other is a semiconductor combustible gas detector.

The catalytic combustible gas detector uses the resistance change of the refractory metal platinum wire to measure the combustible gas concentration. When a flammable gas enters the detector, it causes an oxidation reaction (flameless combustion) on the surface of the platinum wire. The heat generated by it raises the temperature of the platinum wire, and the resistivity of the platinum wire changes. Therefore, when it encounters high temperature and other factors When the temperature of the platinum wire changes, the resistivity of the platinum wire changes, and the detected data also changes.

Semiconductor-type flammable gas detector measures the concentration of flammable gas by using the change of the surface resistance of the semiconductor. The semiconductor gas combustible gas detector has a high sensitivity gas-sensitive semiconductor element. When it encounters a combustible gas in the working state, the semiconductor resistance decreases, and the decrease value corresponds to the concentration of the combustible gas.

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