🔍 Key Concepts

• Heat flow in a water-tube boiler from furnace to generating bank to superheater • The purpose and location of screen tubes, water-wall tubes, and downcomers in a marine boiler • How superheater tubes are shielded from direct radiant heat of the furnace

💭 Think About

• Visualize the gas flow path: from the burners and furnace, what tubes does the hot gas hit first, and what comes after that? • Which component’s main job is to carry water between drums, and which component’s main job is to absorb or block radiant heat before it reaches the superheater? • Think about which of these parts is physically located between the furnace flame and the superheater tubes in a typical water-tube marine boiler layout.

✅ Before You Answer

• Identify which components are primarily circulation parts (move water between drums) rather than shielding parts • Confirm which tube bank sits directly in front of the superheater in the gas path • Eliminate any components that are not actually in the furnace gas stream where radiant heat is strongest