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Working principle of the GX-85N composite gas explosion detector: The GX-85 can detect combustible gases and oxygen. The combustible gas sensor operates on the principle of catalytic combustion, while the oxygen sensor uses the principle of electrochemical cells. Principle of catalytic combustion: Platinum, palladium, and other catalysts are dispersed around the platinum wire, and a durably treated sensing element is brought into contact with oxygen-containing combustible gases. At this point, even if the concentration of the flammable gas is below the lower explosive limit (LEL), a combustion reaction will occur; the heat generated by this combustion reaction causes the temperature of the sensing element to rise, thereby increasing its resistance. Changes in this resistance cause an imbalance in the voltage across the bridge circuit, which in turn generates an electric current. This current is amplified and displayed on the instrument in units of gas concentration. The components used by RIKEN are based on a separate multi-layer film catalytic mechanism, offering long-term stability in product performance, excellent output characteristics, precision, and reaction properties, as well as a long component lifespan. D: Gas detection element; C: Compensation element; R1, R2, R3, R4: Fixed impedance; SW: Switch; Me: Ammeter; E: Power supply; VR1: Variable impedance. Principle of the Galvanic cell: (O2). Structure of the Galvanic cell-type oxygen sensor: On one side of the plastic container, there is a polytetrafluoroethylene membrane with a thickness of 10–30 micrometers that allows good oxygen permeability. Inside the container, a noble metal electrode such as platinum, gold, or silver is placed in close contact with this membrane. The anode is formed on the inner side of the other side of the container or in the remaining space within the container, using metals like lead or cadmium that are prone to ionization. As oxygen passes through the electrolyte, redox reactions occur at the anode and cathode, causing the metal at the anode to ionize and releasing electrons. The magnitude of the current is proportional to the concentration of oxygen. Since the metal at the anode is consumed in this process, the sensor needs to be replaced regularly. 1. Object of measurement: General flammable gases in the atmosphere. When conducting the measurement, it is first necessary to ensure that the environment is free from the following gases: a) gas compounds containing silicon ； b. Sulfides, such as H2S, SO2, etc. 2. In the presence of sewage, dust, metal powder, and water vapor, these substances can cover the surface of the sensor, affecting its performance; therefore, it should be avoided to use the sensor in such environments. The filter membranes and filter cotton should be checked and replaced promptly. 3. Regularly inspect the instrument’s absorption pipeline. A. If the filter cotton is found to be contaminated, it should be replaced promptly. B. If the filter membrane in the absorption tube becomes clogged, causing no flow in the instrument, contact the maintenance center promptly to have the filter membrane inside the absorption tube replaced. 4. Do not block the absorption tube opening with your hand for an extended period, as this will cause the pump to stop working and may not be able to restart. 5. When the instrument is not in use for an extended period of time, it should be stored in the following environment: a. Temperature: 5-35℃ ； b. Humidity: 30-80% RH; c. Environment: no solvent gases present ； d. Avoid direct sunlight; it should be placed inside the packaging box ； 6. Blocking is strictly prohibited. Vent. Additional note: In 1780, the Italian physician Galvani accidentally touched a frog placed on an iron plate with a copper scalpel, and observed that the frog immediately began to convulse; he concluded that there was a tiny electric current flowing, suggesting that it was an internal self-generated electric current produced by the organism itself. Considered to have proposed the prototype of the galvanic cell, he analyzed it from a physical perspective, believing that it was purely an inorganic phenomenon resulting from chemical reactions between two metals and a solution; it was the electric current generated when copper and iron met with solutions on wet animal bodies that stimulated the frog’s legs. It is used for detecting combustible gases in the environment. When the gas detector detects that the concentration of combustible gases in the environment reaches or exceeds the preset alarm value, it immediately issues audio and visual alarms to alert users to take safety measures and prevent explosions, fires, and poisoning incidents, thereby safeguarding lives and property. Flammable gas detectors are widely used in industries such as petroleum, chemicals, metallurgy, municipal services, and mining, and they are essential gas detection instruments for ensuring safe production in factories and mines.