Skin Tube Thermocouple

A Tube Skin Thermocouple is a specialized, rugged temperature sensor designed to measure the surface temperature—or "skin temperature"—of tubes and pipes inside high-temperature processing equipment like fired heaters, reformers, and crude oil furnaces.
Unlike standard insertion thermocouples that measure fluid temperature, the Tube Skin Thermocouple is critical because it measures the metal temperature directly, which is the most important factor for protecting the equipment from failure.
1. Definition and Purpose
Tube Skin Thermocouples (TS T/Cs) are industrial thermocouples that are permanently attached (usually welded) to the outer surface of a process tube.
● Critical Measurement: In fired heaters, the metal tubes absorb intense radiant heat. Measuring the skin temperature is crucial because it is the hottest point of the tube. This temperature must be strictly controlled to prevent:
o Coking: Overheating the tubes causes carbon deposits (coke) to form on the inside, which reduces heat transfer efficiency and further accelerates overheating.
o Creep and Rupture: Sustained high metal temperature weakens the tube material, leading to metal fatigue (creep) and eventual tube rupture, resulting in catastrophic process failure.
2. Applications
These sensors are fundamental for safety, efficiency, and maintenance planning in the Petrochemical, Refining, and Chemical industries. They are used wherever tubes are exposed to radiant heat:
● Fired Heaters and Furnaces
● Crude Oil Pre-Heaters
● Steam Methane Reformers
● Coker Heaters