Block 2 - Maintain the Boiler Pressure Vessel Flashcards
What must be performed by a Licensed Boiler Contractor?
Any repair work on the pressure vessel
This ensures compliance with safety regulations.
Who must be informed about the work being performed on the boiler?
The TSBC Boiler Safety Officer
This is crucial for safety oversight.
What is the ‘frebox end’ in a firetube boiler?
The end exposed to the hottest combustion gases
This is typically considered the back end of the boiler.
What is the purpose of rolling the tubes at the back end of the boiler?
To secure the tubes into the tube sheet and create a seal
This process is critical for maintaining pressure integrity.
What should be done when shutting down the boiler?
Gradually reduce the load and cool the pressure vessel
This prevents damaging temperature differentials.
What should not be done until all pressure is relieved?
Draining the vessels
This prevents uneven contraction and potential leaks.
What may happen if the unit is drained too quickly?
Baking of deposits on heating surfaces may occur
Some heat may be desirable to dry out the boiler’s interior.
What might happen to an odd rolled tube during hydro testing?
It may weep
Re-firing the boiler might tighten the tubes and stop the weeping.
What is one method to check for cracks in the tube sheet?
Using a liquid dye penetrant
This method involves cleaning the workpiece and applying dye to detect cracks.
What happens after the excess surface penetrant is removed?
Developer is sprayed over the wiped area
This helps expose any cracks present.
What may excessive cracking in the tube sheet require?
Tube sheet replacement or condemning of the pressure vessel
This decision is made by the Safety Officer and equipment owner.
What is needed to perform a complete or partial tube sheet replacement?
Licensed boiler contractor employing certified pressure welders
Proper certification is crucial to ensure safety and compliance.
What is Magnetic Particle Examination (MPE)?
A method where a workpiece is magnetized and sprayed with iron particles
This helps in detecting surface cracks.
What does ultrasonic testing provide?
Accurate thickness readings with minimum surface preparation
It’s useful for determining remaining metal thickness in pitted boilers.
What does radiography or X-ray show?
Detail of welds
This is important for assessing the integrity of welds in the boiler.
What is a significant challenge in maintaining water tube boilers?
Gaining sufficient access to the tubes for repair
Often requires removing multiple tubes to reach a single leaking tube.
What can replacement tubes be ordered to meet?
Exact original specifications
This ensures compatibility and efficiency in the replacement process.
What is required to secure replacement tubes in place?
They are expanded into the upper and lower drums
This secures them firmly to maintain pressure integrity.
What must be welded between each tube on the outermost tube wall?
Fins
This creates a pressure-tight combustion side.
