The correct installation of thermal resistors can reduce measurement errors

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This post was last edited by Wang Tianze on 2015-8-31 at 21:48. The installation of thermal resistors should not affect the operation of the equipment or production processes; attention should be paid to ensuring accurate temperature measurement, as well as safety, reliability, and ease of maintenance. To meet the above requirements, the following points should be considered when selecting the installation location and insertion depth of the thermal resistor: 1. To ensure adequate heat exchange between the measuring end of the thermal resistor and the medium being measured, the location of the measurement point should be chosen carefully; it is advisable to avoid installing the thermal resistor near valves, elbows, as well as in dead corners of pipes and equipment. 　　 2. Thermal resistors equipped with protective sleeves suffer from heat transfer and heat dissipation losses; to reduce measurement errors, thermocouples and thermal resistors should have a sufficient insertion depth: ① For thermal resistors used to measure the temperature of the fluid at the center of a pipeline, their sensing ends should generally be inserted into the center of the pipeline (whether installed vertically or at an angle). If the pipe diameter of the fluid being measured is 200 millimeters, the insertion depth of the thermoresistor should be set at 100 millimeters. ② For temperature measurement of high-temperature, high-pressure, and high-speed fluids (such as main steam temperature), in order to reduce the resistance exerted by the protective sleeve on the fluid and prevent the sleeve from breaking under the influence of the fluid, it is possible to use a protection tube with a shallow insertion depth or a thermoresistor in a heat-shielded design. For shallowly inserted thermal resistance protection sleeves, the depth of insertion into the main steam pipeline should be no less than 75 mm ； The standard insertion depth for a heat-shrinkable thermistor is 100 mm. 　　 ③If it is necessary to measure the temperature of the smoke in the flue, even though the flue diameter is 4 meters, a heat resistor with an insertion depth of 1 meter will suffice. 　　 ④When the insertion depth of the measuring element exceeds 1 m, it should be installed as vertically as possible, or a support frame and protective sleeve should be added.