How can overheating in boiler tubes be identified?

Overheating in boiler tubes can be effectively identified by observing tube discoloration or deformation. When boiler tubes experience excessive heat, the resulting thermal stress can change the physical characteristics of the metal. This can often lead to a visible change in color—typically a blue or brown hue due to oxidation—and can also result in warping or bulging of the tube material.

Discoloration indicates that the metal has reached elevated temperatures beyond its normal operating range, potentially compromising the integrity of the tubes. Deformation is a critical warning sign, as it can lead to potential failures such as tube rupture or leaks, which can have severe consequences for boiler operation and safety.

Other methods, such as measuring steam flow rate or monitoring fuel consumption, do not provide direct evidence of tube overheating. While increasing the water flow rate might help in managing the temperature, it is not a diagnostic tool for identifying existing overheating conditions. Thus, the observation of physical changes in the tubes remains the most reliable method for recognizing overheating issues before they lead to serious operational problems.