When do you use a valve actuator?
A valve actuator is used when manual operation of a valve is impractical, unsafe, or too slow. Typical situations:
- The valve is located in a hard-to-reach position
- The valve requires frequent switching or continuous control
- You are working with hazardous media where manual operation poses risks
- Your installation requires a fail-safe position in the event of power or air supply failure
The actuator is mounted on an ISO 5211 top flange and converts electric or pneumatic force into a quarter-turn or linear movement of the valve.
Electric actuator – when to apply?
An electric actuator is the right choice when no compressed air is available or when precise position control is required. The motor is coupled to a worm gearbox that delivers a quarter-turn (90°) or multi-turn movement.
- Quarter-turn: suitable for ball valves, butterfly valves and plug valves
- Multi-turn: for linear valves and control valves
- Supply voltages: 24 VDC, 230 VAC or 400 VAC
Choose an electric actuator when you need positioners with 4–20 mA or HART communication for modulating control. Note: fail-safe operation upon power failure requires a built-in spring or external battery/capacitor.
Pneumatic actuator – when to apply?
A pneumatic actuator is the right choice when compressed air is available (6–8 bar) and fast switching speed or a simple built-in fail-safe is required.
- Rack & pinion: linear-to-rotary conversion for quarter-turn valves. Available as single- or double-acting. With single-acting, the built-in spring automatically provides fail-open or fail-closed.
- Scotch yoke: lever mechanism for higher torques. Suitable for large valve sizes and environments with extreme temperatures or vibrations.
In water treatment and swimming pool technology, pneumatic actuators are widely used due to their fast switching cycles and built-in failsafe. For applications without a compressed air network – such as yacht building and agricultural vehicles – Ebora supplies mainly electric actuators.
Comparison: electric vs. pneumatic actuator
| Feature |
Electric actuator |
Pneumatic actuator |
| Energy source |
Electricity (24V–400V) |
Compressed air (6–8 bar) |
| Switching speed |
- Slower |
+ Fast |
| Fail-safe (built-in) |
- Only with additional component |
+ Via spring (single-acting) |
| Position control |
+ Modulating (4–20 mA) |
- Limited (open/close) |
| Maintenance |
+ Low |
- Air supply line required |
| Suitable for ATEX |
+ With correct version |
+ Intrinsically safe |
Selection criteria for the right valve actuator
When selecting an actuator for your valve, consider the following:
- Valve type: quarter-turn (ball valve, butterfly valve) or linear (gate valve, control valve)
- Break-out torque: the torque required to set the valve in motion – the determining factor for actuator sizing
- Energy source: is compressed air available, or electricity only?
- Fail-safe requirement: must the valve open or close upon failure?
- Environmental conditions: outdoor installation, ATEX zone, IP class (e.g. IP67), temperature range
- Control requirement: on/off or modulating with position feedback
Not sure which combination is right for you? Ebora helps you with the technical selection of both actuator and valve. Request technical advice.
Applications by sector
Ebora supplies valve actuators for a wide range of markets, each with their own requirements for reliability and environmental conditions:
- Water treatment: frequent switching cycles, fail-safe requirements, corrosion-resistant versions
- Swimming pool technology: chemically aggressive environments, compact build, straightforward operation
- Luxury yacht building: space-saving electric actuators, low noise levels, 24 VDC
- Agricultural vehicles: versions for vibration and outdoor use, fast switching response, pneumatic steering valves
- Defence: specials and custom solutions for extreme reliability and certification requirements
For electric ball valves and pneumatic ball valves, Ebora also supplies complete assembled units, ready for immediate use. For ball valves with bare shaft, customer-specific configurations are available, tailored to your installation.
Valve Automation Centre – assembly and certification
Ebora has its own Valve Automation Centre where valves and actuators are assembled, set up and tested. Our technicians handle:
- Mounting the actuator on the valve (ISO 5211 flange)
- Setting limit switches and position indicators
- Testing the correct open and closed position
- Documentation and certification on request
The result: an automated valve that is ready for immediate use in your installation, without any adjustments on site.
Specials and custom solutions
Do you have an application that deviates from standard configurations? Ebora thinks along with you on specific requirements for actuator type, mounting flange, control, or housing. Contact our engineers for custom solutions – including small series or one-off applications.
Frequently asked questions
What is an ISO 5211 flange and why does it matter?
The ISO 5211 top flange is the international standard for the connection between a valve and an actuator. Thanks to this standard, actuators from different manufacturers are interchangeable on valves with the same flange size. When selecting, check the flange size (F03 to F25) and the drive size of the valve.
Which actuator do I choose for a butterfly valve?
For a butterfly valve, always use a quarter-turn actuator. The choice between electric and pneumatic depends on the available energy source and the fail-safe requirement. For large diameters or high sealing pressure, choose a scotch yoke pneumatic actuator for its higher available torque.
Can an existing valve be converted to automated operation?
In many cases this is possible, provided the valve has an ISO 5211 top flange. Ebora assesses technical feasibility and handles assembly and commissioning in the Valve Automation Centre. Send us the technical specifications of your valve for a tailored assessment.
