30+ Years of Precision Instruments
oxygen detector is a special tool professional thermostat for vapor leakage concentration value inspection. the key of oxygen detector is hand-held/portable oxygen detector. The key is to use high-precision thermostat in a physical way, or use organic chemistry. For example, a controller that checks gas pressure is not considered a gas sensor, but heat 
conductive gas analyzers belong to key gas sensors, although they sometimes apply roughly the same basic principles of inspection.
oxygen detector classification
semiconductor material type
this is the use of some hydroxide semiconductor devices, at a certain temperature, the conductivity of pure water with the natural environment vapor composition of the change and the basic principle of production and manufacturing. For example, an ethanol sensor is fabricated based on the principle that the resistance of tin dioxide significantly decreases when it comes into contact with ethanol vapor at high temperatures.
HACH analysis dashboard
advantages
semiconductor material gas sensors can be reasonably used for: methane gas, ethane, propane gas, butane, ethanol, indoor formaldehyde, carbon monoxide, carbon dioxide, ethylene, acetylene gas, vinyl chloride, butadiene, acrylate and many other vapor inspection. In particular, this type of controller is cheap and suitable for the requirements of civil combustible gas detection. The following types of semiconductor material gas sensors are successful: methane gas (gas, biogas slurry), ethanol, carbon monoxide (liquefied gas in large cities), hydrogen chloride, nitrogen dioxide (including allylamine, hydrazine). High-quality controllers can meet the requirements of industrial production inspection. British Cisco, British gas sensor
defects
reliability is weak, subject to environmental impact assessment is very large; in particular, the selectivity of each controller is not Yes, the main output parameters can not be clear. Therefore, it is not suitable for applications requiring precise metrological verification.
ignition type
this kind of controller is to make a heat-resistant metal catalyst layer on the surface of the platinum resistor. at a certain temperature, flammable vapor catalyzes the combustion device on its surface. ignition is the temperature rise of the platinum resistor, the resistor changes, and the transition value is the culvert of the flammable vapor concentration value.
Advantages
The catalytic combustion device type gas sensor can selectively detect flammable vapor: if it cannot be ignited, the controller will not respond. Catalytic combustion–type gas sensors offer accurate metrological verification, rapid response, and a long service life. The output of the controller is immediately related to the explosion risk of the natural environment, and it is a dominant type of controller in the detection service industry.
Defect
Within the flammable gas range, there is no selectivity. In dark fire operations, there is a risk of ignition and explosion. The vast majority of elemental organic vapors have a toxic effect on controllers.
thermal conductivity cell type
each vapor often has its own special thermal conductivity. when the thermal conductivity of two and several vapors is very different, thermal diffusion components can be used to identify the water content of one of the multi-components. Such controllers have long been used for the detection of radon, carbon dioxide, and high-concentration methane.
These gas sensors have a narrow range of applications and are subject to numerous limitations.
photoelectrocatalytic type
a very large part of its flammable and harmful substances often have photoelectrocatalytic specificity and can be oxidized or restored by photoelectrocatalytic air. By utilizing this phenomenon, it is possible to identify gas components and measure gas concentrations. Photoelectrocatalytic gas sensors are divided into many subcategories:
(1), primary battery type gas sensors (also known as: Gavoni rechargeable battery type gas sensors, also known as solid battery type gas sensors, also known as spontaneous charging Battery type gas sensor), their basic principles are the same as dry batteries used by people, only the carbon-manganese metal electrode of the rechargeable battery is replaced by vapor metal electrode. Taking the oxygen sensor as an example, oxygen is restored at the negative electrode, and the electronic device flows into the anode according to the current meter, where the lead metal material is oxidized by air. The magnitude of the electric current is directly related to the oxygen concentration in the cylinder. This type of controller can reliably detect oxygen cylinders, sulfur dioxide, chlorine gas, and other substances.
(2), stable potential difference electrolytic cell type gas sensor, this kind of controller is very reasonable to test oxidizing vapor, its basic principle is different from that of primary cell type controller, its electrochemical corrosion is generated under the mandatory current flow, and it is a real coulomb analysis controller. This kind of controller has been successfully used for: carbon monoxide, hydrogen chloride, radon, nitrogen dioxide, hydrazine, and other vapor testing, is the current toxic and harmful gas detection of popular controller.
