Bank tube failure
How Conclude bank Tube of water tube Punctured:-
The higher temperature difference across outlet of super heater & inlet of Air preheater is the clear indication of bank tube leakage. After the confirmation of bank tube leakage, Boiler has to be cooled down. Open all manhole doors. Boiler has to filled with cold DM Water & Raised pressure up to its working pressure.
Repairing Procedure:-
After getting confirmation of exact location of leakage, Boiler has to be completely drained out. Take the working permit to repair the bank tube leakage.
1. If leakage is of pin hole type then it must welded with suitable & baked welding electrode.
2. If leakage is bulging type the replace that particular bank tube by new one.
3. If leakage are many tubes the entire bank tube required to replaced by new one.
Again Hydraulic test has to be carried out at working pressure. Inspection has to be done to ensure there are no any leakage present. Boiler filling up to 50% drum level. Now boiler is ready for fresh startup.
