Closed loop or open loop system with axialpiston technology from Linde
Open-loop: Pump-inlet and motor-return (via the directional valve) are connected to the hydraulic tank. Linde hydraulics open loop pumps are called HPR, High Pressure Regulable.
Closed-loop: Motor-return is connected directly to the pump-inlet. To keep up pressure on the low pressure side, the circuits have a charge pump (a small gearpump) that supplies cooled and filtered oil to the low pressure side. Closed-loop circuits are generally used for hydrostatic transmissions in mobile applications. Linde hydraulics closed loop pumps are called HPV, High Pressure Variable.
Animation: Close loopsystem
Although the axialpiston motors are suitable for open as for closed loop systems, the integrated purge valve will be used for closed loop sytems only. When applied for open loop, they will be disabled.
