Control Valve · Glossary

What is a Valve Actuator?

diaphragm, piston, electricControl Valve

A valve actuator is the device that produces the force or torque to move a valve, using air pressure, hydraulic pressure or an electric motor.

Valve Actuator Explained

Spring diaphragm actuators are simple and reliable for control valves. Piston actuators give higher thrust and faster strokes. Rack and pinion and scotch yoke actuators drive quarter turn valves.

Actuators are sized for the unbalanced process force, seat load and friction, with a safety margin.

Valve Actuator Formula

F = P × A

F	actuator thrust (N)
P	air pressure (Pa)
A	effective diaphragm or piston area (m²)

Example: 2 bar on a 0.1 m² diaphragm gives 20,000 N, minus the spring force.

Calculators for Valve Actuator

CalculatorActuator Thrust CalculatorFree online calculator with formula and worked example.CalculatorActuator Stroke Time CalculatorFree online calculator with formula and worked example.CalculatorActuator Bench Set CalculatorFree online calculator with formula and worked example.

Free Downloads

Free downloadControl Valve Datasheet Template in Excel with Cv CheckFree download in Excel and PDF.Free downloadOn Off Valve Datasheet TemplateFree download in Excel and PDF.

Frequently Asked Questions

What is a Valve Actuator?

A valve actuator is the device that produces the force or torque to move a valve, using air pressure, hydraulic pressure or an electric motor.

Diaphragm or piston actuator?

Diaphragm for most control valves; piston where high thrust, long stroke or high supply pressure is needed.

When is an electric actuator used?

Where there is no instrument air, or for slow, infrequent moves; modulating electric actuators also exist.

Learn more on the blog

Diaphragm actuator vs piston actuator

A practical guide on instrumentationblog.in with more detail on valve actuator and how it is applied on real plants.

Read Full Article

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