Reading hydraulic schematic

[Chris W]

Hi all,

Recently I am studying some hydraulic drawing but I ain't quite understand the operation of the proportional valve and why so many ports are closed as the drawing attached.
Please help.

 

[Jacc]

This is a LS-valve from HAWE, PSV-3 or PSV-5. The symbols are a bit complex, yes, but it's just a typical LS-valve with inflow compensator and LS A/B relief valves to reduce the pressure out on some functions.
Valves no 4 and 5 from left have A/B to T in neutral, typically for operating something with a counterbalance valve or possibly a motor.