Glossary · Pneumatics and hydraulics
Proportional valve
Also known as: Proportional control valve
German: Proportionalventil
In fluid power, a proportional valve is a valve whose output, such as flow, pressure or direction and flow, changes continuously in proportion to an electrical input signal, typically via a proportional solenoid and often with integrated electronics.
- Fluid power
In one sentence
A proportional valve varies flow or pressure continuously in proportion to an electrical input signal.
Example
A proportional pressure valve sets the clamping force of a press tool from a 0–10 V setpoint given by the PLC.
How it applies
- Engineering: Proportional valves allow smooth acceleration, variable speed and adjustable force. Onboard electronics reduce setup work and provide diagnostics.
- Commissioning: Setpoint scaling, ramps and dead-band compensation are set; closed-loop versions need tuning.
- Operation: Contamination affects accuracy, especially in hydraulics.
- Documentation: Describe setpoint ranges and their physical meaning ("10 V = 6 bar"), behavior on loss of signal or power, and adjustments. Keep parameter values under configuration control.
Proportional valve vs. servo valve
A Servo valve has higher dynamics and accuracy and usually tighter cleanliness requirements; it is used in demanding closed-loop control. Proportional valves are more robust and cheaper; high-response proportional valves blur the line.
In hydraulics, proportional valves are also sensitive to fluid cleanliness, so give the required cleanliness class in the technical data.