Question 287Steam Plants - Assistant Engineer

The correct answer is D) remove settled solids from the water drum. Bottom blow valves are installed on auxiliary water-tube boilers to allow the removal of settled solids, such as sludge and scale, from the bottom of the water drum. This helps maintain the boiler's efficiency and prevents the buildup of deposits that can impair heat transfer and potentially lead to boiler failure. The other answer choices are incorrect: A) Completely draining the boiler in an emergency is not the primary purpose of bottom blow valves. B) Preventing sludge formation in the steam drum is not the main function of bottom blow valves. C) Removing floating impurities from the boiler water surface is typically done through surface blowdown, not bottom blow valves.