Requirements for the use and installation of platinum rhodium thermocouples

Installation requirements for platinum rhodium thermocouples:

Platinum rhodium thermocoupleIt is a commonly used temperature measuring element in temperature measuring instruments, which directly measures temperature and converts the temperature signal into a thermoelectric potential signal, which is then converted into the temperature of the measured medium through electrical instruments (secondary instruments). The installation methods of thermocouples include: threaded connection, flange connection, and welding. Their applicability and requirements vary, mainly depending on parameters such as pressure and temperature. So what aspects should we pay attention to when installing and using? Today, the author will talk about it one by one for everyone.
1. When using thermocouple compensation wires, attention must be paid to model matching, polarity cannot be connected incorrectly, and the temperature at the connection end between the compensation wire and the thermocouple cannot exceed 100 ℃.
2. When using a thermocouple with a large time constant for temperature measurement or control, although the temperature displayed on the instrument fluctuates very little, the actual furnace temperature may fluctuate greatly. In order to accurately measure temperature, a thermocouple with a small time constant should be selected.
3. After correctly wiring and powering on according to the instrument wiring diagram, the instrument first displays the thermocouple index number of the instrument, then displays the instrument range, and then the digital tube in the lower row of the instrument displays the set temperature, and the digital tube in the upper row of the instrument displays the measured temperature.
4. Thermocouples cannot be installed in areas where the measured medium flows very little. When measuring the gas temperature inside a tube with a thermocouple, it must be installed against the flow velocity direction and fully in contact with the gas.
5. In order to ensure sufficient heat exchange between the measuring ends of thermocouples and thermal resistors and the measured medium, the position of the measuring point should be selected reasonably, and the valve should be avoided as much as possible
6. According to the law of intermediate conductor, in practical temperature measurement applications of thermocouples, the hot end is often welded and the cold end is open circuited. The cold end is connected to the display instrument through a connecting wire to form a temperature measurement system.