With heat resistance bimetallic thermometer works






with heat resistance the bimetallic thermometer is in the low temperature area one of the most commonly used temperature detector. Can be directly measured in the process of various production - 80 - + 500 ℃ within the scope of liquid, vapour and gas medium, as well as solid surface temperature measurement. Its main characteristic is high accuracy, stable performance. The platinum thermal resistance measurement accuracy is the highest, it is not only widely used in industrial temperature measurement, and is made into standard benchmark instrument.
1.
thermal resistance temperature measurement principle and material thermal resistance temperature measurement is based on the metal conductor resistance value increases with the increase of the temperature of the properties for temperature measurement. Heat resistance is mostly made of pure metal materials, the application at present most is platinum and copper, in addition, now have begun to use the materials such as nickel, manganese and rhodium manufacturing thermal resistance.
2, thermal resistance of type
1) Normal thermal resistance
in temperature measuring principle of thermal resistance, measured the change in temperature is directly measured by the change of the thermal resistance tolerance, therefore, the thermal resistance of lead wire and other wire resistance change will affect temperature measurement.
2) Transverse thermal resistance
end heat resistance temperature sensing element resistance wire winding by special processing, close to the face in the thermometer. Compared with general axial thermal resistance, it can reflect more correctly and quickly end face of the actual temperature being measured, is suitable for measuring temperature bearing and other parts of the face.
3) Armored thermal resistance
armored thermal resistance is by thermal components ( The resistor body) , wire, insulation materials, stainless steel casing combination solid body, its diameter is commonly & phi; 2 - - φ 8 mm, minimum & phi; mm。 Compared with the normal thermal resistance, it has the following advantages:
(1) small volume, no internal air gap, thermal inertia, small measuring hysteresis;
2. Good mechanical properties, resistance to vibration and impact resistant;
3. Can bend, easy to install
4. Long service life.
4) Flameproof thermal resistance
flameproof thermal resistance through the special structure of the junction box, put the shell internal explosive mixed gas by affected by sparks or electric arc explosion limit within the junction box, that wouldn't make production field explosion. Flameproof thermal resistance can be used in the Bla - B3c level zone with explosion danger place temperature measurement.