Analyzing the occurrence of faults based on the principle of combustible gas detectors
1. Combustible gas detector is a detector installed and used in industrial and civil buildings that responds to single or multiple combustible gas concentrations. The most commonly used combustible gas detectors in daily life are 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.
2. A catalytic combustible gas detector uses the resistance change of a refractory platinum wire heated to measure the concentration of combustible gases. When combustible gas enters the detector, it causes an oxidation reaction (flameless combustion) on the surface of the platinum wire. The heat generated increases the temperature of the platinum wire, and the electrical resistance of the platinum wire changes. Therefore, when encountering high temperatures and other factors, the temperature of the platinum wire changes, and the electrical resistance of the platinum wire changes, and the detected data also changes.
3. 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.
4. 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 platinum wire resistance to increase, causing the bridge circuit to lose balance. Therefore, a voltage signal is output, and the magnitude of this voltage is proportional to the concentration of combustible gas. The signal is amplified, analog-to-digital converted, and displayed on a liquid display to display the concentration of combustible gas. 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, the square wave generator outputs a set of square wave signals to control the sound, light detection circuit, and buzzer to produce continuous sound. The light-emitting diode flashes and sends out a detection signal. From the principle of the combustible gas detector, it can be seen that if electromagnetic interference occurs, it will affect the detection signal and result in data deviation; If there is a collision or vibration that causes the equipment to break, the detection will fail; If the environment is too humid or the equipment is flooded, it may also cause a short circuit in the combustible gas detector or a change in the resistance value of the circuit, resulting in detection faults.
