š Key Concepts
ā¢ Think about what the boiler wrapper sheet is on a marine boiler ā it is the plate that wraps around and forms the outer wall of the furnace/combustion chamber, not the steam space inside the drum and not the tube bank itself.
ā¢ Compare the arrows that point to drums or openings (like the steam drum and manhole) versus those that point to flat or curved plates forming the furnace enclosure.
ā¢ In this sectional view, identify the area where the combustion space is, then look for the plate that separates that hot furnace from the water/steam space and tubes ā that plate is the wrapper sheet.
š Think About
ā¢ First, locate the furnace/combustion chamber in the illustration. Which side of the boiler shows the burner and flame path?
ā¢ Which labeled arrow is pointing to the metal plate that surrounds that furnace, rather than to a drum, tube bank, or manhole cover?
ā¢ Of the answer letters given (A, B, C, H, I), which one is pointing directly at a sheet or wall around the furnace, instead of the interior of the steam drum or a group of tubes?
ā
Before You Answer
ā¢ Verify that your chosen letter points to a sheet/plate forming a wall, not a round drum, manhole cover, or tube bank.
ā¢ Confirm that the part you pick is in the area surrounding the furnace/combustion zone, where the burner is located in the illustration.
ā¢ Make sure the arrow is not indicating individual tubes or the main generating bank, since the wrapper sheet is a continuous plate, not separate tubes.