The advantages of WRNM surface thermocouples are mainly accurate measurement, etc.

Nowadays, WRNM surface thermocouples are still relatively widely used in the field of industrial chemical industry, especially in power plants, chemical production, high-temperature furnaces and other production. WRNM surface thermocouples are almost always used as temperature measurement elements. Other types of thermocouples account for a very small proportion. Large enterprises all use reliable WRNM surface thermocouples. The main reason is that WRNM surface thermocouples have many advantages.
The advantages of WRNM surface thermocouples are accurate measurement, good temperature performance, high temperature resistance, long service life, and it can be suitable for different oxidizing and inert atmospheres. The application range and field are extremely wide. It is used as a temperature sensing element. Generally, it needs to be used in conjunction with temperature transmitters, displays and other components. As a thermal set for temperature control, WRNM surface thermocouples have a wide temperature measurement range. It can measure gases, liquids, and solids in the range of 0~1800°, and can also be used for steam measurement.
The working principle of WRNM surface thermocouples is that when the two ends of two conductors of different components are connected into a loop, when the temperatures of the two junctions are different, a thermal current will be generated in the loop. If there is a temperature difference between the working end and the reference end of the thermocouple, the display instrument will indicate the temperature value corresponding to the thermoelectric potential generated by the thermocouple.
WRNM surface thermocouples are divided into various models according to the different measured temperatures. When the measured temperature is normally between 1000 and 1300 °C, it is recommended to use a single WRNM surface thermocouple (platinum-rhodium 10-platinum). If the measured temperature is normally between 1200 and 1600 °C, it is recommended to use a double WRNM surface thermocouple (platinum-rhodium 30-platinum-rhodium 6). In this way, the service life of the WRNM surface thermocouple can be guaranteed within the temperature range used.
WRNM surface thermocouples are precious metal thermocouples. The wire diameter is specified as 0.5mm, with an allowable deviation of -0.015mm. The nominal chemical composition of the positive electrode (BP) is a platinum-rhodium alloy, which contains 30% rhodium and 70% platinum. The negative electrode (BN) is a platinum-rhodium alloy, which contains 6% rhodium, so it is commonly known as a double WRNM surface thermocouple. The maximum long-term use temperature of the thermocouple is 1600℃, and the maximum short-term use temperature is 1800℃.

WRNM surface thermocouple is a commonly used temperature measuring element in temperature measuring instruments. It directly measures temperature and converts temperature signals into thermoelectric potential signals, which are converted into the temperature of the measured medium through electrical instruments (secondary instruments).

The appearance of various WRNM surface thermocouples is often very different due to needs, but their basic structure is roughly the same. They are usually composed of main parts such as thermocouples, insulating sleeve protection tubes and junction boxes. They are usually used in conjunction with display instruments, recording instruments and electronic regulators.

Two conductors of different components (called WRNM surface thermocouple wires or thermocouples) are connected at both ends to form a loop. When the temperatures of the two junctions are different, an electromotive force will be generated in the loop. This phenomenon is called the thermoelectric effect, and this electromotive force is called the thermoelectric potential.