BM3 Boilers Ch 5

What is the process called when a tube is expanded into a drilled hole?

• Tube grooving
• Tube seating
• Tube rolling
• Tube flaring

What type of tube seats are used for boilers operating under lower pressure?

• Plain tube seats
• Grooved tube seats
• Pressure tube seats
• Finned tube seats

Grooved tube seats are used for boilers that operate at

• Lower pressures
• Higher pressures
• Low temperatures

What is the circumferential pitch?

• Distance between two grooves
• Distance between two tube holes
• Centre to centre distance between tube holes
• Tube wall thickness

What are the components of a roll expander?

• Rolls, Cage, Mandrel
• Spool, Roller, Nut
• Seal, Plug, Nozzle
• Gear, Shaft, Collar

What is the function of the mandrel in a roll expander?

• To cut the tube
• To drive the rolls into the tube
• To flare the tube ends
• To expand the rolls

Bell rolls are used to

• Expand the tube
• Groove the tube
• Flare the tube end
• Weld the tube

Self-feed expanders are designed so that

• The mandrel is stationary
• The rolls are stationary
• The mandrel travels into the expander
• The cage rotates the tube

Retractive expanders are designed for

• Short tube holes
• Thick tube holes
• Thin wall tubes
• Rolled tube seats

What is the purpose of using a lubricant in tube rolling?

• To cool the tube
• To avoid slippage
• To avoid heat generation
• To ensure mill scale removal