Question 179Steam Plants - 1st Asst/Chief

The correct answer is D) a water seal line to the packing gland. The leakage of air into the pump casing is prevented by a water seal line to the packing gland. The water seal creates a positive pressure that prevents air from being drawn into the pump suction, which would decrease the pump's efficiency. This water seal is a common feature in the design of condensate pumps to maintain the integrity of the pump's operation. The other options are incorrect because: A) the vacuum in the pump suction alone is not sufficient to prevent air leakage, B) special packing in the stuffing box does not actively create a seal, and C) an air seal line from the compressed air line would introduce air into the system, which is the opposite of what is required.