Question 309Steam Plants - 1st Asst/Chief

The correct answer is C) The pressure differential assists in seating the valves when the lifting beam is lowered. In a turbo generator equipped with a lifting beam mechanism, the pressure differential between the nozzle block and the steam chest helps to ensure that the valves are properly seated when the lifting beam is lowered. This pressure differential creates a force that pushes the valves down, aiding in their closure and creating a tight seal. This is a key function of the lifting beam mechanism, as it helps to maintain the efficiency and safety of the turbine operation. The other answer choices are incorrect because they do not accurately describe the role of the pressure differential in the lifting beam mechanism. The use of a balance piston, a biasing spring, or the elimination of valve binding are not directly related to the pressure differential in this specific system.