🔍 Key Concepts

• Location and orientation of the horizontal tubes relative to the generating tube bank in the illustration • Normal purpose of through stays vs. soot blower elements in boiler construction • Where steam smothering lines are usually placed in relation to the furnace and casing

💭 Think About

• Look closely at the ends of the horizontal tubes: do they appear fixed as structural supports, or arranged so something can flow through them and exit as jets? • Ask yourself which of the listed items would need to pass completely across the gas path through the generating bank to do its job. • Consider which components (from the choices) are usually outside the gas pass versus inside it.

✅ Before You Answer

• Verify which item’s main function is to clean tube surfaces while the boiler is operating. • Verify where through stays are typically found (in fire-tube vs. water-tube boilers, and in flat plate areas). • Verify whether steam smothering lines would normally be run directly through the generating tube bank or routed along the furnace/uptakes instead.