October 8, 2026
A valve actuator converts an energy source into mechanical movement to open, close or position a valve.
Bettis is a valve automation brand with a broad range of electric, pneumatic and hydraulic actuation solutions. Its pneumatic portfolio includes both Scotch yoke and rack-and-pinion designs for different quarter-turn valve requirements.
For industrial valves, the actuator is not simply an accessory. The actuator must provide sufficient torque throughout the valve operating cycle while also matching the required failure position, operating pressure, temperature and installation conditions.
This is why selecting a Bettis actuator should start with the valve requirements rather than the actuator model alone.
The basic operating principle depends on the actuator design.
For a pneumatic actuator, compressed air enters the actuator chamber and generates force on a piston or other internal mechanism. The resulting linear movement is converted into rotary movement at the actuator output.
This rotary movement is transmitted to the valve stem or shaft.
For a quarter-turn valve such as a ball or butterfly valve, approximately 90 degrees of rotation is typically required for full opening or closing.
The actuator therefore needs to generate enough torque to overcome the valve's operating resistance.
The general operating sequence is:
Pneumatic or hydraulic energy → Actuator movement → Torque → Valve shaft rotation → Valve opening or closing
Additional accessories such as a valve positioner, solenoid valve, limit switch, switchbox or manual override can be integrated according to the control requirements.
Pneumatic actuation is one of the main areas of the Bettis portfolio.
Current Bettis pneumatic products include Scotch yoke designs such as the G-Series, CBB-Series and CBA300 Series, as well as rack-and-pinion products such as the RPE-Series and RPX-Series.
These products are used for different quarter-turn valve automation requirements.
The Bettis G-Series is a pneumatic Scotch yoke actuator designed for 90-degree rotating mechanisms, including ball, butterfly and plug valves.
Its modular construction allows different power and spring configurations. Spring-return and double-acting arrangements are available depending on the required valve operating and failure functions.
One notable feature is the Tension-Lok system, which locks the spring module during maintenance and helps prevent accidental release of stored spring energy.
The G-Series is therefore particularly relevant when the application requires high torque, fail-safe operation or demanding environmental performance.
For applications where a more compact actuator package is preferred, Bettis offers the CBB-Series and CBA300 Series.
The CBB-Series is a compact pneumatic Scotch yoke actuator for quarter-turn valves. It combines the Scotch yoke operating principle with a relatively compact package.
The CBA300 Series is another compact pneumatic Scotch yoke actuator. It provides ISO/DIN bottom mounting and NAMUR-standard accessory mounting, which can simplify integration with valves and pneumatic accessories.
These compact designs can be considered when space, installation and overall package size are important selection factors.
Bettis also offers rack-and-pinion pneumatic actuators, including the RPE-Series and RPX-Series.
Unlike a Scotch yoke actuator, a rack-and-pinion design converts the linear movement of the piston into rotary output through a rack and pinion mechanism.
This design is commonly considered for quarter-turn valves where a compact and straightforward rotary actuator arrangement is required.
When comparing a rack-and-pinion actuator with a Scotch yoke actuator, the key point is not simply which design is better. The torque requirement, valve type, available air pressure, space limitations and required operating profile should all be considered.
Pneumatic power is not the only option for Bettis valve automation.
Bettis also provides hydraulic Scotch yoke actuators for demanding applications where hydraulic power can provide the required operating force and torque.
The Bettis G-Series hydraulic actuator is designed for ball, butterfly and plug valves as well as other 90-degree rotating mechanisms.
Hydraulic actuation can be particularly useful where high torque is required or where the available operating power source makes hydraulic actuation more suitable than conventional pneumatic operation.
Bettis also offers gas-hydraulic solutions for pipeline applications. The GH-Series, for example, uses high-pressure pipeline gas as the power source and converts that energy into hydraulically controlled torque.
This type of actuator is relevant to pipeline applications such as mainline valves, compressor station emergency shutdown and remote valve control.
One of the most important actuator decisions is whether the valve requires spring return or double acting operation.
A spring-return actuator uses compressed air or hydraulic pressure to move the actuator in one direction while a mechanical spring provides the return movement.
If the operating power is lost, the spring can drive the valve toward its predefined fail position.
Depending on the valve and actuator configuration, this may be:
Fail open
Fail closed
Another predefined safe position
Spring return is therefore commonly considered when the process requires a defined valve position following loss of power or operating pressure.
A double-acting actuator uses pressure on both sides of the piston to produce movement in both directions.
This configuration does not rely on a mechanical spring for the normal return stroke.
It can provide high operating torque and is suitable when the control system determines both opening and closing movements.
However, if a defined emergency position is required during loss of air or hydraulic power, an additional fail-safe arrangement may be necessary.
Selecting the actuator should begin with the valve.
Confirm whether the valve is:
Ball valve
Butterfly valve
Plug valve
Damper
Louver
Another quarter-turn mechanism
The valve shaft and mounting dimensions must match the actuator.
Torque is one of the most important actuator selection parameters.
The required actuator torque should account for the valve's actual operating torque, including breakaway, running and seating requirements where applicable.
Do not select an actuator simply because its maximum torque looks higher than the valve's nominal requirement.
The complete torque curve should be considered across the valve's operating range.
For pneumatic actuators, determine the available instrument air pressure.
Check the minimum, normal and maximum pressure rather than using only the nominal plant air pressure.
The available pressure directly affects actuator output torque.
Ask whether the valve needs to:
Fail Open, Fail Closed or Fail in Place.
This decision affects the actuator configuration, spring arrangement and associated pneumatic accessories.
The actuator may operate outdoors, in corrosive environments, in hazardous areas or under extreme temperatures.
Environmental protection, materials, coatings and applicable certifications should therefore be checked before selecting the final configuration.
Even a properly selected actuator can develop problems if the valve assembly is not maintained correctly.
If the actuator cannot provide enough torque under actual operating conditions, the valve may fail to fully open or close.
Possible causes include incorrect sizing, insufficient air pressure, increased valve friction or changes in process conditions.
Pneumatic actuator leakage can reduce available operating pressure and affect actuator response.
Inspect tubing, fittings, seals and actuator connections when abnormal movement or slow response is observed.
Slow operation may result from insufficient air supply, restricted tubing, contaminated pneumatic components or incorrect accessory settings.
The actuator should be checked together with the solenoid valve, positioner and pneumatic circuit.
A valve that moves in the wrong direction during loss of air or power may indicate an incorrect spring arrangement or pneumatic configuration.
This should be verified during commissioning and maintenance rather than discovered during an actual emergency.
Sometimes the actuator is not the root cause.
A valve with increased stem or seat friction can require substantially more torque than during its original commissioning.
When an actuator appears undersized, the valve operating torque should also be checked.
When replacing an existing Bettis actuator, the original model number is useful but may not be enough.
For a reliable replacement check, provide:
Original actuator model
Valve manufacturer and model
Valve type
Valve size
Valve pressure class
Required operating torque
Available air or hydraulic pressure
Spring return or double acting
Fail-open or fail-closed requirement
Valve mounting standard
Shaft or stem dimensions
Operating temperature
Hazardous-area or certification requirements
Existing accessories
For older Bettis products, it is also important to check current product status. Some historical Bettis series have been discontinued, so a replacement may require identifying a current equivalent rather than simply supplying the original model.
Bettis valve actuators cover a wide range of industrial valve automation requirements, from compact pneumatic quarter-turn actuators to modular Scotch yoke designs and hydraulic solutions for demanding applications.
The Bettis G-Series is particularly suited to applications requiring a robust Scotch yoke actuator, while the CBB-Series and CBA300 Series provide more compact pneumatic options. Rack-and-pinion products such as the RPE and RPX Series provide another solution for quarter-turn valve automation.
The right actuator should ultimately be selected according to the valve torque, operating pressure, required failure position, actuator type, environmental conditions and mounting requirements.
For a Bettis actuator quotation or replacement check, providing the original model number together with the valve and operating parameters is the fastest way to confirm the suitable configuration.
