Rotork’s latest electric control valve actuation technology has been selected for the automation of metering pumps in Group 2C hazardous areas in an automation project at an oil refinery in India. Sixteen CVA (model number CVL500) linear actuators with IECEx international explosionproof certification have been ordered to control metering pump valve positions by means of a 4-20 milliamp signal and provide remote status indication.
The actuators are also equipped with hand drive mechanisms to enable manual operation of the valves. The CVA is engineered to deliver high precision valve positioning and facilitate the tightest possible tolerances on the process variable in order to optimise process quality and output. On loss of mains power, built-in super capacitors enable the CVA to move the valve to a desired position, programmable as open, close, any intermediate position or stay-put.
The CVA uses a variant of Rotork’s ‘non-intrusive’ wireless communication technology for actuator programming, commissioning and adjustment. Actuator set-up and configuration is performed using a Bluetooth enabled PDA or PC running Rotork Enlight software. Every CVA incorporates an onboard data logger, enabling operational data including 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 into the actuator.
Mechanical features include the industry proven Rotork ‘double-sealed’ enclosure, whereby the internal electrics are permanently protected from the effects of the ambient atmosphere. The IP68 dust tight, watertight and temporarily submersible (7m, 72hrs) enclosure is universal to all the models in the CVA range, including those with hazardous area approvals.