Chemical cleaning to remove scale from inner surface of boiler tubes has periodically been conducted to prevent accidents of overheating, hydrothermal eruption and blowout breakage. In order to minimize the cleaning frequency, appropriate grasp of timing of the chemical cleaning is important, and accurate temperature measurement of water wall tubes is required. “Embedded-in-Grooves” type water wall tube skin thermocouples, co-developed with the Central Research Institute of Electric Power Industry in Japan for high durability, accuracy and workability, have been widely used by customers.
