Over Centre Valve by Al - Ameen Enterprises

Application
Overcentre valves give static and dynamic control of loads
by regulating flow into and out of hydraulic actuators. The
overcentre valve will stop the load from running away in
the event of a hose burst. If open centre directional control
valves are used, they will allow the thermal expansion
relief of the hydraulic fluid. These valves provide excellent
hose burst protection.
Operation
The check section allows free flow into the actuator (from
2 to 1) then holds and locks the load against movement
(from 1 to 2). The pilot pressure in the pilot port (3) will give
a controlled movement to piston when the pressure is
applied. The pressure required to open the valve and allow
movement depends on the pilot ratio of the valve. For
optimization of load control and energy usage, a choice of
pilot ratios can be made available. The pressure required to
open the valve and start actuator movement can be
calculated as follows:
Pilot Pressure = (Relief Setting) - (Load Pressure)
Pilot Ratio