Question 572Steam Plants - Assistant Engineer

The correct answer is C) They commonly use a conventional valve disc and a balance piston. Balanced throttle valves are designed to have a balanced force on the valve disc, which allows for easier operation and better control. The use of a conventional valve disc and a balance piston is a common design for balanced throttle valves, as it helps to counteract the forces acting on the valve disc and maintain a neutral position. The other options are incorrect: A) The ahead throttle valve does not normally utilize a guarding valve, as the balanced design already provides the necessary control. B) Both ahead and astern valves typically have a positive opening tendency, not a balanced one. D) Balanced throttle valves commonly use a single valve disc and a balance cylinder, not two parallel seats.