For the installation of the thermocouple and thermal resistance, gas should be paid attention to for 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 thermocouple and thermal resistance of the installation site and insertion depth when should pay attention to the following:
1, in order to make the gas thermocouple and thermal resistance measurement of end and have good heat exchange between the measured medium, should be a reasonable choice of observation, try to avoid the valve, elbow and pipe of elements and equipment installed near the thermocouple or heat resistance.
2, with a protection casing thermocouple and thermal resistance of heat transfer and heat loss, in order to reduce the measurement error, thermocouple and thermal resistance should have enough insert depth:
(1) for measuring pipeline fluid temperature at the centre of the thermocouple, generally the measuring end is inserted into the pipe should be installed (vertical or inclined). The center such as the current body of pipe diameter is 200 mm, the thermocouple or heat resistance should choose insert depth 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 under the effect of fluid fracturing, the way protecting tube shallow inserted 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, the thermocouple or heat resistance 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.