Question 647Steam Plants - Assistant Engineer

The correct answer is C) The pressure differential assists in seating the valves when the lifting beam is lowered. The differential pressure between the nozzle block and steam chest in a turbo-generator equipped with a lifting beam mechanism helps to seat the valves when the lifting beam is lowered. This pressure differential creates a force that pushes the valves closed, ensuring a tight seal and proper valve operation. The other options are incorrect because: A) The pressure differential does not eliminate the possibility of valve binding, B) A special biasing spring is not required due to the pressure differential, and D) A special balance piston is not necessary to accommodate the pressure differential in this system.