The Four Laws of Wear resistant Thermocouples

Wear resistant thermocouple is a temperature measuring outer tube and wear-resistant head made of special heat-resistant materials and wear-resistant alloy materials. Based on the difference in measured temperature, the selected wear-resistant maintenance tube material also varies. It adopts flange connection or threaded connection methods and can be temporarily used to stop temperature measurement in the range of 0-1400 degrees. It is the most ideal temperature sensor for low-temperature and wear-resistant situations in metallurgy, chemical, cement plants, power plants, and fluidized bed boiler industries.
1. The law of homogeneous conductor: A closed circuit is formed by welding two ends of a homogeneous material (conductor or semiconductor), regardless of the cross-section of the conductor and the temperature distribution. There will be no war potential, and the temperature difference potential will relatively dissipate. The total potential in the circuit is zero.

It can be seen that wear-resistant thermocouples must be formed by two different homogeneous conductors or semiconductors. If the data of the hot electrode is uneven, due to the existence of a temperature gradient, an additional heating potential will occur.

2. Side conductor law: When a side conductor (third conductor) is connected to a wear-resistant thermocouple circuit, only if the temperature at both ends of the side conductor is the same, the introduction of the side conductor does not affect the total potential of the wear-resistant thermocouple circuit. This is the side conductor law.

Utilization: According to the law of adjacent conductors, in the practical temperature measurement utilization of wear-resistant thermocouples, the situation of hot end welding and cold end open circuit is often adopted. The cold end is connected to the performance instrument through a connecting wire to form a temperature measurement system.

Some people are concerned that using copper wires to connect the cold end of wear-resistant thermocouples to the instrument for reading mV values may cause additional measurement deviations due to the potential of the contact between the wires and wear-resistant thermocouples. According to this law, there is no such deviation!

3. The law of temperature nearby: The thermoelectric potential between the two contacts of the wear-resistant thermocouple circuit (at temperatures T and T0) is the algebraic sum of the thermoelectric potential of the wear-resistant thermocouple at temperatures T and Tn and the thermoelectric potential at temperatures Tn and T0. Tn refers to the temperature next to it.

Utilization: Due to the non-linear relationship between wear-resistant thermocouples E-T, when the cold end temperature is not 0 degrees Celsius, it is not possible to directly use the known circuit's actual thermoelectric potential E (t, t0) to calculate the hot end temperature value by looking up the table; It is also not possible to directly use the known circuit's actual thermoelectric potential E (t, t0) to calculate the temperature value by looking up the table, and to determine the measured temperature value of the hot end by adding the cold end temperature. The modification should be stopped according to the temperature law next to it. Beginners often do not follow the temperature law nearby to make modifications!

4. Reference electrode law: This law is only discussed and studied by professionals, and some production and application personnel may not fully understand it. Simply put, it is: using high-purity platinum wire as the scale electrode, assuming that the positive and negative electrode resolution of nickel chromium nickel silicon wear-resistant thermocouple is matched with the scale electrode, the sum of their values is the value of this nickel chromium nickel silicon thermocouple.