In compensators, which component acts on the rolling diaphragm to set the pressure?

In compensators, which component acts on the rolling diaphragm to set the pressure?

• A. Spring
• B. Piston
• C. Hydraulic fluid
• D. Weight

Answer: (A)

The pressure setpoint in a compensator comes from the preload force applied to the rolling diaphragm by a spring. The rolling diaphragm forms the movable interface between the hydraulic fluid side and the control side, and the spring pushes on it to create a resisting force. As hydraulic pressure pushes on the diaphragm, it rolls and shifts, altering the flow path to regulate the pressure. The point at which the hydraulic force on the diaphragm balances the spring force determines the pressure the system maintains. Because the spring preload is adjustable, you can set the desired pressure. The hydraulic fluid simply provides the pressure signal to be balanced; a weight or a piston isn’t used to establish the setpoint in this arrangement, making the spring the component that sets the pressure.