Typically water tube boilers are used in industries including power generation (nearly exclusively), and marine uses, due to their capability to function at function at higher pressures.
The inspection of boiler tubes is of significance for many reasons. In the electricity generation sector especially, efficacy is a driving factor. Due to the big profits involved, even modest improvements in efficiency or modest changes down time can create drastic changes in earnings. Security is perhaps the largest, with routine review helping prevent another driving factor, blow outs and potentially fatal accidents from happening.
Review is done via non-destructive techniques, utilising "Non-Destructive Testing". Technologies including ultrasonic and electromagnetic are ordinarily employed, and can provide the rest of the thickness of the seamless tube walls, in addition to details of the defects themselves. Visual inspection is more difficult to reach places and also accustomed to identify any clear problem areas in conjunction with borescopes for internal review.
Various areas of the boiler can be scrutinized, from boiler generating banks, to waterwall tubes. Straight sections and bend sections could be analyzed, and defects uncovered and quantified. Superheaters, reheaters and economisers may also be scrutinized.
Tube groundwork varies on the technology used, and is of concern also. With ultrasonic techniques, a clean surface and good contact is necessary, so tubes will need to be cleaned to a high standard in the right review times.
Other technologies such as with LFET (Low Frequency Electromagnetic Technique) require less preparation, with a small uniform scale not an issue. Nonetheless, nonuniform scales can be problematic, due to issues with lift off