Question 383Steam Plants - Assistant Engineer

The correct answer is A) a water seal line to the packing gland. The purpose of the water seal line is to prevent air from leaking into the pump casing through the packing gland. The water seal creates a barrier that stops air from being drawn into the pump, which could disrupt the pump's operation. This is an important safety feature to maintain the proper vacuum and pressure within the pump system. The other options are incorrect because: B) the vacuum in the pump suction alone is not enough to prevent air leakage; C) an air seal line would introduce air into the system, which is the opposite of what is needed; and D) while special packing can help, a water seal line is the primary method for preventing air leakage through the packing gland.