The principle of operation of thermocouples, discovered back in the century before last, is widely used to measure temperatures in a variety of environments with a fairly high accuracy in our time. Like any other device, they require regular maintenance, health checks, refurbishment (repair) and replacement of major components. More detailed information can be obtained on the website of the company https://olil.ru/services/recovery , which provides services for the maintenance of thermocouples, and we Let's take a closer look at the causes of the problems.
Reasons for failure of thermocouples
The most reliable in terms of temperature readings accuracy and durability are thermocouples with thermoelectrodes made of so-called pure metals, which include gold, platinum and palladium. Due to their high cost, they are used exclusively in research centers with a high enough budget for laboratory testing.
In the domestic industry, devices using platinum-rhodium alloys (PR) are used. The main reason for their unstable work is:
- Formation of contamination at the ends of thermoelectrodes.
- Evaporation and oxidation processes on sensors.
These processes occur as a result of the leakage of the thermocouple body, as a result of which aggressive media and humidity have a destructive effect on the electrodes.
Oxidation of rhodium and the resulting lack of it leads to a temperature change in the dependence of the EMF and thermoelectric inhomogeneities. Without timely maintenance, which consists in restoring the junction, the thermoelectrode is simply destroyed. It should be remembered that timely repair and maintenance will prevent unscheduled equipment downtime resulting from thermocouple failure.
