🔍 Key Concepts

• Water-tube boiler circulation path – know which tubes carry water/steam up vs. cooler water down • Density of sludge and scale – heavier particles settle where water moves slowest and is coolest • Location of mud/low-point drums or headers in water-tube boilers

💭 Think About

• Trace the flow of water and steam in a typical water-tube boiler and ask: where would heavy particles naturally settle? • Which tubes or sections operate at lower temperature with slower flow, making them natural collection points for sludge? • Think about where boiler blowdown connections are usually placed to remove sludge—what part of the system are they trying to clean?

✅ Before You Answer

• Identify which option represents the lowest point / coolest circulating path in the system • Confirm which tubes are primarily for downward flow of water versus upward flow of steam-water mixture • Recall where bottom blowdown is normally taken from in water-tube boilers