What to do if the thermocouple has a short life?

The short life of thermocouples will increase costs and affect the normal measurement work. The life of thermocouples can be extended by correct selection, optimized installation, and enhanced maintenance. The following are specific measures:
Correct selection
Choose according to the measurement environment: In harsh environments such as high temperature, strong corrosion, and high vibration, thermocouples with corresponding temperature resistance, corrosion resistance, and vibration resistance should be selected. For example, in an environment with sulfide corrosion, thermocouples with special anti-corrosion coatings or materials can be selected.
Choose according to the measurement temperature: Different types of thermocouples have different temperature measurement ranges. It is necessary to ensure that the temperature measurement range of the selected thermocouple can cover the actual measurement temperature and have good stability and accuracy at this temperature. For example, when measuring high temperatures above 1300℃, platinum-rhodium thermocouples can be selected.
Optimize installation
Choose a suitable installation location: Avoid installing thermocouples in locations with large temperature gradients, strong airflow impacts, large vibrations, and areas close to strong electromagnetic fields. For example, in industrial furnaces, thermocouples should be installed in areas with uniform temperature and stable airflow.
Ensure the correct installation method: During installation, ensure that the thermocouple is in full contact with the object being measured so that heat can be effectively transferred. For solid objects to be measured, insert installation can be used and thermal grease can be used to enhance thermal conductivity; for fluids, the thermocouple should be perpendicular to the flow direction of the fluid to ensure the accuracy and stability of the measurement.
Strengthen maintenance
Regular cleaning: Regularly clean the dust, oil, impurities, etc. on the surface of the thermocouple to prevent them from affecting heat transfer and corroding the thermocouple. For thermocouples used in dusty environments, they can be cleaned once a week.
Check insulation performance: Regularly check the insulation resistance of the thermocouple to ensure good insulation performance. If the insulation resistance is found to be reduced, the cause should be found in time and the insulation material should be replaced or the damaged part should be repaired.
Check the connection parts: Frequently check the connection parts such as the terminal and solder joint of the thermocouple to ensure that the connection is firm and there is no looseness, oxidation, etc. If oxidation is found in the connection part, it should be cleaned and reconnected in time.
Control the use conditions
Avoid over-temperature use: Strictly operate in accordance with the use temperature range of the thermocouple to avoid long-term use in an environment that exceeds its maximum allowable temperature. For example, the K-type thermocouple generally does not exceed 1200℃. Exceeding this temperature may accelerate the aging and damage of the thermocouple.
Reduce temperature fluctuations: Try to keep the measured temperature stable, reduce rapid changes and frequent fluctuations in temperature, so as to reduce the risk of damage to the thermocouple due to thermal stress. For example, in the control of the heating furnace, an advanced temperature control system can be used to control the temperature fluctuation within a smaller range.
Regular calibration and testing
Regular calibration: According to the prescribed calibration cycle, the thermocouple is sent to a professional metrology agency for calibration, and the measurement error is discovered and corrected in time to ensure its measurement accuracy. Generally speaking, for thermocouples with higher accuracy requirements, calibration is performed every six months; for thermocouples for general industrial use, calibration can be performed once a year.
Real-time monitoring: Some online monitoring technologies can be used to monitor the working status of the thermocouple in real time, such as monitoring the stability of the thermoelectric potential, changes in resistance value, etc., to discover potential problems in time and take measures.