Open loop / closed loop hydraulic pump difference 1

[UKAndy]

Im looking at building a diesel driven hydraulic power pack using a variable displacement swash plate type piston pump. Whats the difference between an open loop and closed loop unit.

 

[EdDanzer]

Open loop systems return all oil pumped to the tank, closed loop only return oil used for work. In a closed loop system the pump must destroked when no work is being done. If you choose a closed loop system try to have load sensing to increase efficiency of the system. Unless you need the pressure of a piston pump most open loop systems are gear or vane pumps, much less expensive.