The issue of the replacement cycle for thermocouples
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Thermocouples are important reference parameters during operation and serve as a direct basis for adjusting product quality. However, there is certainly an issue related to the cycle time in their use; I wonder how your company defines this concept, and what determines it? If, during maintenance, it is removed and found to be in good condition, can it be used again? With long-term use, will the material of the protective tube change? I would appreciate it if fellow sailors could provide professional answers. Thank you.
**There is no explicit provision regarding this, but manufacturers generally guarantee a usage period of over 6 months! It mainly depends on the environment in which it is used.
There is no fixed replacement cycle; it depends on the operating conditions in which it is used. In ammonia synthesis plants, for example, the thermocouples used to measure the temperature in the furnace chamber of a certain section need to be replaced frequently due to the high temperatures there. . . . . . . . The removed thermocouples, although intact, are still calibrated before being reinstalled.
Here, it is inspected once a year, and those that pass the inspection can continue to be used.
The service life and environmental factors are very important; some can be used for over 10 years, while others only last 2–4 months. We have examples of both types. As long as the protective sleeve is not severely worn, it can continue to be used. The protective sleeves that we have used for over 10 years are continued to be used by rotating them so that the worn side faces the other way. Based on the degree of wear, an approximate assessment of the remaining service life can be made during each major maintenance check. However, in general, thermocouples used in fluidized beds have a short lifespan and need to be replaced frequently; it is therefore necessary to keep sufficient spare parts on hand