Technisch principe van gas detector
De gas detector is een instrument speciaal ontworpen om de veilige concentratie van gas. Het werken principe is voornamelijk om om de fysisch of chemisch niet-elektrisch signalen opgevangen door het gas sensor in elektrische signalen, en dan rectificeren en filter de boven elektrische signalen door externe circuits, en controle de corresponderende modules door deze verwerkte signalen aan naar realiseren gas detectie. Echter, de kern van de gas detector is de ingebouwd sensor component. Volgens aan de verschillende gassen aan be gedetecteerd, de detectie technische principes zijn verschillend. Voor voorbeeld, de gemeenschappelijk technisch principes van het gas detector omvatten katalytisch verbranding, elektrochemie, infrarood, PID, warmte geleiding, optisch golfgeleider en zo op. Kan de vrienden weten wat functioneel kenmerken zijn verschillend tussen zij?
1. Principe van katalytisch verbranding technologie
The technical principle of catalytic combustion gas detector is that it adopts the principle of Wheatstone bridge, and the detection element and compensation element are paired to form one arm of the bridge. Wanneer brandbaar gas is aangetroffen, vlamloos verbranding optreedt op het oppervlak van de gevoelige lichaam van de detectie element, de temperatuur van de gevoelig lichaam verhoogt, de weerstand van de temperatuurgevoelig materiaal toeneemt, en de uitgang spanning van de brug verhogingen, which toename in direct verhouding met de toename van gas concentratie. De concentratie van de detectie gas kan behoord volgens aan de verandering van de uitgang signaal van de detectie brug.
2. Principes van halfgeleider technologie
The technical principle of the semiconductor gas detector is that it changes the conductivity of the semiconductor by the adsorption of the gas to be measured, and excites the alarm circuit by comparing the current changes. The semiconductor sensor is greatly influenced by the environment when meting, so the output linearity is unstable. Because of its sensitive response, semiconductor sensors are wide used in measuring microlekkage van gas.
3. Principe van elektrochemische technologie
4. Het principe van infrarood technologie
The technical principle of infrared gas detector is based on Lambert-Beer law, and its physical law is that when a beam of parallel monochromatic light passes vertically through a uniform and non-scattering light-absorbing substance, its absorbance is directly proportional to the concentration of light-absorbing substance and the thickness of absorption layer. The commonly used infrared wavelength of infrared gas detector is 2 ~ 12 μ m. Simply put, the principle of infrared gas detector is that the gas to be measured continuously passes through a container with a certain length and volume, and a beam of infrared light is injected from one of the two light-permeable end faces of the container, and then the radiation intensity of infrared light is measured at the other end face. Finally, the concentration of the gas to be measured can be known according to the direct ratio between the absorption of infrared light and the concentration of light-absorbing substances.
5. PID technologie principe
The technical principle of photo-ion PID gas detector is that it can be easily detected by a detector through an ultraviolet light source, and positive and negative ions generated by chemical substances under its excitation. Ionization occurs when molecules absorb high-energy ultraviolet rays. Under this excitation, molecules generate negative electrons and form positive ions. The current generated by these ionized particles can be amplified by the detector, and the concentration of ppm can be displayed on the outside. After passing through the electrode, these ions quickly recombine and become the original organic molecules together. Molecules will not be damaged in this process.
6. Principle of heat conduction technology
The heat conduction gas detector is a new detection principle for meting brandbaar gas, which mainly analysers the concentration of the measured gas by meting the change of thermal conductivity of mixed gas. Gewoonlijk, the difference of thermal conductivity of thermal conductivity gas sensor is converted in the change of resistance through circuit. De traditionele detectie methode is naar verzenden de gas naar be gemeten in a gas kamer, en het centrum van de gas kamer is a thermistor, such as a thermistor, platinum wire or wolfraam draad, which is verwarmd naar a bepaald temperatuur naar convert de verandering van thermisch geleidbaarheid van de gemengd gas in de verandering van weerstand van de thermistor, en de verandering van weerstand kan be gemakkelijk en nauwkeurig gemeten.
