What are the installation requirements for bimetal thermometers?


For the installation of bimetal thermometers, it should be noted that it is conducive to accurate temperature measurement, reliability and convenient maintenance, and does not affect equipment operation and production operations. To meet the above requirements, pay attention to the following points when choosing the installation location and insertion depth of the thermal resistance. point:

bimetal thermometer

(1) In order to make sufficient heat exchange between the measuring end of the thermal resistance and the measured medium, the position of the measuring point should be selected reasonably, and the thermal resistance should be avoided as far as possible near the dead ends of valves, elbows and pipes and equipment.

(2) The thermal resistance with a protective sleeve has heat transfer and heat dissipation losses. In order to reduce the measurement error, the thermocouple and thermal resistance should have sufficient insertion depth:
a. For the thermal resistance measuring the fluid temperature in the center of the pipeline, the measuring end should generally be inserted into the center of the pipeline (vertical installation or inclined installation). If the pipe diameter of the fluid to be measured is 200 mm, the insertion depth of the thermal resistance should be 100 mm;

b. For the temperature measurement of high-temperature, high-pressure and high-speed fluids (such as the main steam temperature), in order to reduce the resistance of the protective sleeve to the fluid and prevent the protective sleeve from breaking under the action of the fluid, the protective tube shallow insertion method or the heat-sleeve type can be adopted. Thermal resistance. For shallow-insertion thermal resistance protection sleeves, the depth of insertion into the main steam pipeline shall not be less than 75mm; the standard insertion depth of heat-sleeve thermal resistance is 100mm;

c. If it is necessary to measure the temperature of the flue gas in the flue, although the diameter of the flue is 4m, the insertion depth of the thermal resistance is 1m;

d. When the insertion depth of the measuring element exceeds 1m, it should be installed as vertically as possible, or a support frame and a protective sleeve should be installed.

The bimetal thermometer combines two metals with different linear expansion coefficients, and one end is fixed. When the temperature changes, the thermal expansion of the two metals is different, which drives the pointer to deflect to indicate the temperature. This is the bimetal thermometer, as shown in the picture on the previous page. The temperature measurement range is -80~500C, which is suitable for temperature measurement when the industrial precision is not high. As a temperature sensing element, bimetal can also be used for automatic temperature control.
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