Control Valves

Parts of a hydraulic valve manifold

Point at a number or a part of the drawing.

1. 1Manifold block

   Steel block drilled with oil passages. The valves bolt onto it or screw into it, which replaces most of the piping between them.

2. 2Directional valve

   Solenoid valve that switches oil between the two ports of a cylinder or motor, to start, stop and reverse a movement.

   Directional Control Valve

3. 3High-flow solenoid valve

   Larger, pilot-operated directional valve: a small solenoid valve on top shifts the main spool. Used for clamping and injection on large machines.

   Solenoid Operated Valve — High Flow

4. 4Proportional valve

   Sets pressure or flow in proportion to an electrical signal from the controller, so speeds and pressures follow the profile set on the screen.

   Proportional Pressure/Flow Valve

5. 5Relief valve

   Limits the system pressure. When the pressure goes above its setting it opens and sends oil to the tank.

   Relief Valve / Safety Valve

6. 6Cartridge valve

   Valve inserted into a bore in the block, shown here in section. A spring-loaded poppet opens or closes a large passage; used for high flows in clamping, injection and ejection circuits.

   Cartridge Valve

7. 7Check valve

   Lets oil flow one way only, for example from the pump into the circuit, and blocks it from flowing back.

   Check Valve