Orsaker till förbringning av skruvtermoelement

Screw thermocouples are usually composed of temperature sensing elements, mounting fixtures, and junction boxes{{0}} They are assembled thermocouples produced in accordance with IEC standards. At the same time, the series and model spectrum of the thermocouples uniformly designed by the Ministry of Machinery and Electronics Industry are adopted. It kan direkt mäta yttemperaturen på vätska, ånga, gasformigt medium och fast i intervallet 0 grader till 400 grader i olika produktionsprocesser .
Embrittlement is the most common factor in the scrapping of screw thermocouples. The thermocouples are embrittled due to contamination, grain growth, redox reactions, and long-term recrystallization at high temperatures. The thermocouples are used in atomic reactors and are bombarded by neutrons. Some elements in them are transformed into other elements, changing the composition of the thermocouples. For example, the rhodium of the armored platinum-rhodium thermocouple will be transformed into palladium, and a small amount of platinum will first become gold and then mercury, which will change the thermoelectric properties and reduce the thermoelectric potential. Some cheap metal thermocouples, such as iron, nickel-chromium, and nickel-aluminum (silicon), do not undergo obvious neutron radiation transmutation. However, copper undergoes a large change in composition due to transmutation under radiation. Therefore, in the presence of neutron radiation, it is more appropriate to use nickel-chromium-nickel-aluminum thermocouples, and Nickel-Chromium-Silicon-Nickel-Silicon (N-Type) Termoelement är bättre .
During the measurement process, the screw thermocouple will cause instability in the measurement results due to measurement conditions and environmental restrictions. For example: contamination, oxidation, reduction, physical conditions, brittle cracking, and irradiation are the main sources of instability in thermocouple measurement results.