CVA electric actuation for larger control valves
10/05/2012The new CVL-5000 actuator extends the scope of Rotork Process Controls’ innovative CVA electric control valve actuator range to enable the automation of larger valves and valves with higher pressure ratings.
Providing a maximum rated thrust of 5000lbsf (22241N) and a linear stroke length of up to 4.5 inches (115mm), the CVL-5000 retains all the features and benefits of the established Rotork CVA range, providing highly accurate control valve automation combined with advanced, non-intrusive calibration, valve diagnostics and the simplicity and economy of electric operation.
CVA actuators deliver 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 is quoted at <0.1% of full scale, offering suitability for the most demanding applications.
Mechanical features include Rotork’s well-proven ‘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 (7 metres, 72 hours) enclosure is universal to all models in the CVA range, including those with hazardous area approvals. On loss of mains power, built-in super-capacitors allow the actuator to move the valve to a desired position, programmable as open, close, any intermediate position or stay-put. Manual operation is available as standard on the CVL-5000 and as an option on other CVA models.
CVA actuators utilise Rotork’s innovative and well established ‘non-intrusive’ 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 which is freely 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 detailed investigation and diagnosis. After analysis, any required configuration changes can be uploaded into to the actuator.
Digital control bus connectivity options include Hart and Foundation Fieldbus protocols, facilitating enhanced installed economy as well as giving the CVA the increased ability to dovetail into existing asset management systems. The all-electric design, which can be specified for single-phase AC or DC supplies, also simplifies the process of retrofitting actuators onto existing valves.
The introduction of the CVL-5000 coincides with the launch of the new Rotork CMA (Compact Modulating Actuator) range, which brings many of the benefits of CVA electrical actuation to small linear and rotary control valves. The combined performance of the two ranges enables Rotork’s innovative electrical control valve actuation technologies to be applied to process control applications of virtually any size and description.