The minimum pressure valve will prevent a portion of a pressure system from dropping below a set minimum pressure. Initially, as inlet pressure builds, the valve will open at a preset opening pressure allowing pressure to build throughout the system. When pressure at the outlet is reduced enough, the valve closes to maintain pressure at the inlet. An independent check valve prevents back flow.
In a rotary screw air compressor, the minimum pressure valve maintains a minimum pressure in the air-oil separator. At start-up, the valve is closed to build initial pressure. At normal operating pressures, the valve is full open for minimal pressure loss. In addition, this valve has a independent poppet type check valve to prevent back flow at shut down.
Minimum Pressure Valves