🔍 Key Concepts

• Boiler water circulation in auxiliary water-tube boilers (steam drum vs. water drum/mud drum) • Difference between surface blow (skimmer or continuous blowdown) and bottom blow (intermittent blowdown) • Where sludge and scale tend to collect inside a water-tube boiler

💭 Think About

• Think about whether a bottom blow valve would deal with material that floats or that settles—where would each type of impurity be located? • Consider which part of a water-tube boiler (steam drum or water drum/mud drum) is at the lowest point where heavy solids would accumulate. • Ask yourself: is a bottom blow typically used continuously for fine control of boiler water chemistry, or intermittently to discharge heavier accumulated material?

✅ Before You Answer

• Identify whether floating impurities collect at the surface in the steam drum or at the bottom of the boiler. • Confirm that bottom blow valves are located at the lowest points in the boiler where heavier solids and sludge settle. • Distinguish between surface (continuous) blowdown and bottom (intermittent) blowdown functions before choosing.