Rotork launches electric actuator

Rotork has launched an electric valve actuator for the operation of process control valves.

The Rotork CVA range provides continuous, repeatable modulating control with a programmable fail-to-position option.

Operating on an industry-standard 4-20mA control signal or digital bus, the resolution, repeatability and hysteresis performance of the CVA is quoted at <0.1 per cent of full scale.

The result is a range of actuators that demonstrates accurate control valve automation, combined with advanced, non-intrusive calibration, valve diagnostics and the economy of electric operation.

It is available for the direct-drive actuation of linear or quarter-turn control valves.

Mechanical features include Rotork double-sealed enclosure, whereby internal electrical components are permanently protected from the effects of the operating atmosphere.

The IP68 dust tight, watertight and temporarily submersible (7m, 72 hours) enclosure is universal to all models in the CVA range, including those with hazardous area approvals.

The CVA is engineered to deliver precision valve positioning and facilitate the tightest possible tolerances on the process variable, enabling process quality and output to be optimised.

On loss of mains power, built-in super capacitors allow the CVA to move the valve to a desired position.

Manual operation is also available.

The CVA utilises a new variant of Rotork communication technology for actuator programming and adjustment.

Actuator set-up and configuration is performed using a Bluetooth enabled PDA or PC running Rotork Enlight software that is downloadable from the Rotork website.

Every CVA incorporates an onboard data logger, enabling operational data such as valve-torque profiles, dwell times, actuator events and statistics to be downloaded for investigation and diagnosis.

After analysis, any required configuration changes can be uploaded to the actuator.

Digital control bus connectivity options for the CVA include Hart and Foundation fieldbus protocols, giving the CVA the increased ability to dovetail into existing asset-management systems.

The all-electric CVA design also simplifies the process of retrofitting actuators onto existing valves.

Rotork's Site Services organisation is available on a global basis to provide comprehensive support in these areas, from advice and surveys to installation and commissioning.

When complete, the full range of CVA actuators will have a maximum rated thrust of 22.2kN (5000lbsf) with a maximum stroke of 114.3mm (4.5in), while quarter-turn actuators will supply a maximum rated torque of 677.5Nm (6000in/lbs), enabling the range to operate most control valve types and sizes.

Actuators can be specified for single-phase AC or DC electrical supplies.

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