Control; The Control Valves; Operating Principle - Etesia HYDRO 124D Technical Training Manual

2.2) Control

2.2.1) The control valves

General points
The control valves control the movements of the receivers (rams or motors). They act as "points"
switching the hydraulic flow from the pumps to the different uses.
They are characterised by "O/P" (O= number of openings / P= number of positions)
In our case, we use only two types of control valve in the equipment circuit :
4/3 Control valve
Centre closed
Start closed
Cross parallel with
Electrical control
2/2 Control valve
with electro-hydraulic control

Operating principle

Let us take the example of a 4/3 control valve with manual control (as can be found on the MVEHH
for the control of the grassbox emptying).
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