Explosion-proof thermocouple installation note what is _ instrument

Installation of explosion-proof thermocouple, should pay attention to accurate temperature measurement, safety examination and maintenance is convenient, and does not affect the equipment operation and production operations. To meet the above requirements, in the choice of the installation site of the thermocouple and insertion depth should pay attention to the following points 1, explosion-proof thermocouple with a protection casing with heat transfer and heat loss, in order to reduce the measurement error, thermocouple and thermocouple should have enough: (insert depth 1) For measurement of pipeline fluid temperature explosion-proof thermocouple, generally should be measuring end is inserted into the pipe ( Vertical or inclined installation) 。 As the current body of pipe diameter is 200 mm, the thermocouple insertion depth should choose 100 mm; ( 2) For high temperature and high pressure and high velocity of temperature measurement, Such as main steam temperature) , in order to reduce cases of fluid resistance and prevent cases break under the action of a fluid, can take protecting tube shallow inserted way or use hot thermocouple. Shallow inserted type thermocouple protection tube, its depth into the steam pipe should be no less than 75 mm; Heat sets the standard of thermocouple insertion depth is 100 mm; ( 3) If is need to measure the temperature of flue gas, although the flue is 4 m in diameter, thermocouple insertion depth of 1 m. ( 4) When measuring the original insertion depth of more than 1 m, shall be installed vertically, as far as possible or add racks and protect casing. 2, in order to make the measurement end of the thermocouple, and had good heat exchange between the measured medium, should be a reasonable choice of observation, try to avoid the valve, elbow and thermocouple pipeline and equipment near the corner of installations. The system composing of thermocouple ( 1) Thermocouple temperature measurement system in general by the thermocouple, connecting wires and display instrument, etc. Must pay attention to the following two points: (1) the thermocouple and the index number of the display instrument must agree (2) in order to eliminate the influence of the connection wire resistance change, must use three wire connection. Specific content see this chapter 3. （ 2) Thermocouple, thermocouple is by thermal components ( The resistor body) , wire, insulation materials, stainless steel casing combination solid body, its diameter is commonly from 1 to 8 mm, achieve more xiaoke phi is 0. 25mm。 Compared with conventional type thermocouple, it has the following advantages: (1) small volume, no internal air gap, 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.