Pilot Operated Valve
On large hydraulic valve the force needed to operate the valve also increases. If the force is too large for solenoid or manual operation, then we can use pilot operated valve.
The working principle of pilot operated valve is shown in figure above. In the example the valve 1 is used to move a ram, since the force required to operate the valve is too large then we use valve 2 as the pilot valve. On typical hydraulic schematic pilot pressure lines are shown dotted.
In the figure the valve will retract if the pilot port Z is depressurized with the solenoid on valve 1 deenergized. If the pilot Z on valve 2 is pressurized then the ram will extend.
We can simplify the circuit above by using a pilot/main valve assembly so we only use one valve to operate the ram. We can use a hydraulic 4/2 pilot operated spool valve to solve the problem.
Categories: Hydraulic Valves | Tags: pilot | Leave a comment