Question 362Steam Plants - Assistant Engineer

The correct answer is B) Usually the surface blow pipe is perforated with holes along its top surface; however, when a scum pan is also employed, the holes are located along the bottom of the pipe surface. The reasoning behind this is that the surface blow pipe is designed to remove impurities and contaminants that accumulate on the surface of the boiler's water. By placing the perforations along the top surface of the pipe, the impurities can be effectively removed from the surface of the water. However, when a scum pan is used, the perforations are placed on the bottom of the pipe to allow the impurities to be blown out of the scum pan. The other answer choices are incorrect because they do not accurately reflect the standard practices for boiler steam drum surface blow piping.