Pressure relief valve, piloted

In normal position the valve is closed. If the opening pressure is reached at P, T opens. When the pressure drops below the preset level, the valve closes again. In simple terms, the pilot pressure is generated by the input pressure. The flow direction is indicated by the arrow.

The pilot operated pressure relief valve consists of a pilot stage and a main stage. When open, there is less volumetric flow at the pilot stage that leads internally to connection T.

The hydraulic resistance relates to the completely opened valve.