The thermocouple and the use of the thermocouple method is _ instrument

Commonly used in low temperature zone thermocouple is a kind of temperature detector. Thermocouple temperature measurement is based on the metal conductor resistance value increases with the increase of the temperature of the properties for temperature measurement. 1, proficient in thermocouple: industrial commonly used thermocouple temperature sensing element ( The resistor body) The structure and characteristics. From the thermocouple temperature measurement principle, the measured the change in temperature is directly measured by thermocouple resistance change, therefore, the wires of a thermocouple body such as a variety of wire resistance change will affect temperature measurement. As to eliminate the influence of the lead resistance with the three wire or four wire system. 2, thermocouple, thermocouple is by thermal components ( The resistor body) , wire, insulation materials, stainless steel casing combination solid body, its diameter is generally from 2 to 8 mm, achieve more xiaoke phi is 0. 25mm。 Compared with ordinary thermocouple, it has the following advantages: (1) small volume, no internal air gap and thermal inertia, the measured value after small; (2) good mechanical properties, resistance to vibration and shock. (3) can bend, easy to install (4) long service life. 3, end thermocouple: end thermocouple temperature sensing element resistance wire winding by special processing, close to the face in the thermometer. Compared with general axial thermocouple, 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. 4, explosion-proof explosion-proof thermocouple, thermocouple through special explosion-proof explosion-proof junction box structure, its 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. Explosion-proof explosion-proof thermocouple can be used in the Bla ~ B3c zone with explosion danger place temperature measurement. The working principle of the thermocouple is based on baker ( seeback) Effect, that is, two different components of conductor ends connected into a circuit, such as two different connection end temperature, then to produce the physical phenomenon of thermal current in the circuit.