Installation method of thermocouple and thermal resistance temperature meter

Infineon / Mitsubishi / Fuji / Semikron / Eupec / IXYS

Installation method of thermocouple and thermal resistance temperature meter

Posted Date: 2024-02-05

The installation method of thermocouples and thermal resistance temperature meters should meet the requirements for accurate temperature measurement, safety and reliability, while not affecting the operation and production operations of the equipment. Here are some installation suggestions:

1. The installation position of the temperature source component should be selected in a place where the medium temperature changes sensitively and is representative. It should not be located near resistance components such as valves, in dead corners of the medium flow stream, or in places with large vibrations.

2. The thermocouple source components should be installed away from strong magnetic fields.

3. The installation of temperature source components on the process pipeline should comply with the following regulations:

★When installed vertically with the process pipeline, the axis of the source component should intersect perpendicularly with the axis of the process pipeline.

★When installed obliquely with the process pipeline, it should be against the flow direction of the medium, and the axis of the source component should intersect with the axis of the process pipeline.

4. Temperature measuring components installed on dusty process pipelines should take protective measures to prevent wear.

5. When the thermocouple or thermal resistor is installed in a place susceptible to strong impact from the medium being measured, and when the insertion depth is greater than 1 meter when installed horizontally or the measured temperature is greater than 700°C, anti-bending measures should be taken.

6. The temperature-sensing surface of the surface thermometer should be in close contact with the surface to be measured and firmly fixed.

7. Install the thermometer on the elbow tube. During installation, the axis of the thermometer must coincide with the center line of the straight section of the elbow tube.

8. When using a thermocouple to measure furnace temperature, avoid direct contact between the temperature measuring component and the flame, and it should not be too close or installed next to the furnace door. The junction box should not touch the furnace wall to prevent the cold end of the thermocouple from overheating.

9. When using thermocouples and thermal resistors to measure temperature, the introduction of interference signals should be prevented, and the opening of the junction box should be directed downward to prevent water vapor, dust, etc. from entering and affecting the measurement.

10. If the process pipeline is too small, an expansion pipe can be installed where the temperature measurement component is installed. Thermocouples, thermal resistors, bimetal thermometers in DN

11. When installing the thermocouple, it should be placed as close as possible to the temperature control point to be measured. In order to prevent heat from being transferred along the thermocouple or preventing the protective tube from affecting the measured temperature, the thermocouple should be immersed in the fluid being measured to a depth of at least 10 times its diameter. When measuring the temperature of a solid, the thermocouple should be held against or in close contact with the material. To minimize thermal conduction errors, the temperature gradient near the junction should be reduced.

12. When using a thermocouple to measure the gas temperature in a pipe, if the pipe wall temperature is significantly higher or lower, the thermocouple will radiate or absorb heat to it, thereby significantly changing the measured temperature. In this case, a radiation shield can be used to bring the temperature close to the gas temperature, using a so-called screen thermocouple.

13. When selecting a temperature measurement point, it should be representative. For example, when measuring the temperature of a fluid in a pipeline, the measuring end of the thermocouple should be at the point where the flow rate is maximum in the pipeline. Generally speaking, the end of the thermocouple's protective tube should cross the flow centerline.

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