Thermocouple Verification Service

Having an accurate temperature profile of reactors can alert operators of small problems before they become large ones. However, the process of checking thermocouples usually requires significant downtime and, thus, expense. WIKA’s Multipoint Thermocouple Verification Service is a fast and efficient way of testing TC assemblies without disrupting normal operations.

Refineries and petrochemical plants rely on multipoint thermocouple assemblies to monitor temperature at critical process points. This is one way for operators to gauge how well a reactor and its catalyst are performing. But while thermocouples (TCs) are robust and accurate temperature sensors, with time they will begin to drift and fail. That’s why it’s so important to verify thermocouples at regular intervals and to repair/replace them as needed. This can also function as the proof test required for compliance with SIL systems.

However, most multipoint TC assemblies can be tested only during normal operations, and this process is not very accurate. Moreover, it does not allow for physically correcting a sensor if its reading is off. Basically, all that an operator could do is to note the problem, and then wait for the next outage before being able to correct or replace the faulty sensor.

To overcome this challenge, WIKA created a better product. The Gayesco Flex-R®is the only multipoint thermocouple system on the market that can be tested right after installation. We also offer this verification as a standalone service to be performed during catalyst changeouts.

The Importance of Thermocouple Verification


All thermocouples should be tested and “retuned” about every four years to ensure they’re still giving an accurate temperature profile of reactor processes. A verification service can detect exactly which TCs in the multipoint assembly are no longer performing as they should, such as if a hot junction (thermocouple tip) is damaged and should be repaired or replaced.

WIKA’s Verification Test: Fast and Comprehensive


WIKA’s high-temperature verification service is a complete system diagnostic that checks not only the accuracy of each thermocouple, but also the assembly’s wiring, transmitter, and output signals. During the test, WIKA technicians heat each thermocouple to 700°F (371°C), and then use equipment calibrated as per NIST guidelines to check the functionality of the entire system. We can verify as many as 9 or 10 points per hour. In most cases, a full thermocouple calibration cycle takes only a few hours, which easily fits into the timeframe for changing out the reactor’s catalyst.

This service is as non-disruptive as it is efficient. With our specialized equipment, thermocouple verification does not require scaffolding, and there’s minimal impact on a reactor’s turnaround schedule. It also saves refineries millions of dollars by allowing multipoint installations to operate at peak performance for 25 to 30 years. Other similar systems last only 10 to 15 years.

Designed for each specific vessel and application, Gayesco Flex-R® multipoint thermocouple systems have become the industry standard for fixed-bed reactors, hydrocracking processes, and fluid catalytic cracking (FCC) units in refineries and petrochemical facilities. There are currently more than 2,300 of these assemblies – with 140,000-plus measuring points – in reactors around the world. Contact WIKA USA’s electronic temperature specialists for more information on how our Multipoint Thermocouple Verification Service can help you save time and money.

Product mentioned in this article:

Model TC96-R Gayesco Flex-R® multipoint thermocouple



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