Rotork’s CVA electric actuator has been specified for critical valve control duty on high temperature gas turbine pre-heater equipment supplied to the power generation industry. The application demands unrestricted modulation of a three-way valve to control the pre-heated temperature of fuel gas for electricity generating turbines. The Rotork CVA actuators have been installed on seven skid-mounted units supplied to Riyadh PP11, a power plant project serving the capital city of Saudi Arabia. Manufactured by Petrogas Gas Systems in The Netherlands, the units heat the gas on its way to the turbines by passing it through a chamber that is surrounded by an oil bath that is heated to a temperature of 185C.
A CVA actuator controls the position of a three-way valve on the inlet side of each unit to ensure that the process does not overheat. Operating from a 4 - 20mA control signal, the actuator moves the valve to control the heat output. Precise and responsive valve positional control, with repeatability and resolution at less than 0.1%, makes an important contribution to the overall high efficiency of the pre-heating performance. Seven ATEX certified explosion-proof CVQ quarter-turn actuators have been supplied to operate 200mm Class 300 valves.
The double-sealed CVA design also provides permanent environmental protection to IP68, with non-intrusive setting and commissioning technology. An integral data-logger facilitat