Thermocouple degradation refers to the gradual loss of accuracy and reliability in a thermocouple due to environmental and operational factors. Over time, exposure to high temperatures, oxidation, contamination, mechanical stress, or thermal cycling can alter the properties of the thermocouple wires, affecting the voltage-temperature relationship and leading to inaccurate readings.
Common Causes of Thermocouple Degradation:
- Oxidation & Contamination: Exposure to oxygen, chemicals, or moisture can cause corrosion or contamination of the thermocouple wires, altering their electrical properties.
- Thermal Cycling & Aging: Repeated heating and cooling cycles can change the microstructure of the thermocouple materials, leading to drift in temperature readings.
- Mechanical Stress: Bending, stretching, or vibration can physically damage the wires, causing breaks or inconsistencies in the thermoelectric signal.
- Electrical Interference: Nearby electromagnetic fields or ground loops can introduce noise, distorting the thermocouple’s signal.
Effects of Thermocouple Degradation:
- Reduced accuracy and repeatability
- Increased signal drift over time
- Potential failure leading to unreliable or no readings
Preventing Thermocouple Degradation:
- Use protective sheathing or insulation to reduce exposure to contaminants
- Select thermocouples rated for the operating temperature and environment
- Perform regular accuracy checks and replace degraded thermocouples as needed