Introduction to the principle of operation of combustible gas detectors
Combustible gas detector is a detector installed and used in industrial and civil buildings that responds to single or multiple combustible gas concentrations.
There are two types of combustible gas detectors commonly used in daily life: catalytic combustible gas detectors and semi conductive combustible gas detectors.
Semiconductive combustible gas detectors are mainly used in places such as restaurants, hotels, and home production rooms that use gas, natural gas, and liquefied gas. Catalytic combustible gas detectors are mainly used in industrial places that emit combustible gases and vapors.
A semi conductive combustible gas detector uses changes in semiconductor surface resistance to measure the concentration of combustible gases.
The semiconductor combustible gas detector uses gas sensitive semiconductor components with high sensitivity. When it encounters combustible gas during operation, the semiconductor resistance decreases, and the decrease value is related to the concentration of combustible gas.
The combustible gas detector consists of two parts: detection and detection, with detection and detection functions.
The principle of the combustible gas detector detection part is that the sensor of the instrument uses detection elements, fixed resistors, and a zero potentiometer to form a detection bridge circuit.
The bridge circuit uses platinum wire as the carrier catalytic element. After being powered on, the temperature of the platinum wire rises to the working temperature, and air reaches the surface of the element through natural diffusion or other means.
When there is no combustible gas in the air, the output of the bridge circuit is zero. When there is combustible gas in the air and it diffuses onto the detection element, flameless combustion is generated due to catalytic action, causing the temperature of the detection element to rise and the resistance of the platinum wire to increase, causing the bridge circuit to lose balance;
Pressure signal output, the magnitude of this voltage is proportional to the concentration of combustible gases. The signal is amplified, analog-to-digital converted, and displayed on a liquid display to display the concentration of combustible gases.
The principle of the detection part is that when the concentration of the combustible gas being measured exceeds the limit value, the amplified bridge output voltage is matched with the circuit detection set voltage;
Through a voltage comparator, a square wave generator outputs a set of square wave signals to control the sound and light detection circuit. The buzzer produces continuous sound, and the light-emitting diode flashes, emitting a detection signal.
