For the installation of bimetallic thermometers, attention should be paid to the following points when selecting the installation location and insertion depth of thermal resistance: (1)In order to make full heat exchange between the measuring end of the thermal resistance and the medium under test, the location of the measuring point should be reasonably selected, and the installation of thermal resistance near the dead angle of valves, elbows, pipes and equipment should be avoided as far as possible. (2)Thermometer with protective sleeve has heat transfer and heat dissipation losses. In order to reduce measurement errors, thermocouples and thermal resistance should have sufficient insertion depth. A . For the thermometer used to measure the temperature of the fluid in the center of the pipeline, the measuring end should generally be inserted into the center of the pipeline (vertical or inclined installation). B. For temperature measurements of high temperature, high pressure and high speed fluids (e.g. main steam temperature), in order to reduce the resistance of protective sleeve to fluids and prevent the protective sleeve from breaking under the action of fluids, shallow insertion of protective tube or hot sleeve thermal resistance can be adopted. C. If it is necessary to measure the temperature of the flue gas in the flue, although the diameter of the flue is 4 m, the insertion depth of the thermal resistance is 1 m. D. When measuring the insertion depth of the original part exceeds 1 m, it should be installed vertically as far as possible, or with brackets and protective sleeves.