Part-Turn Actuator

Part-Turn Actuator. Part Turn actuators are required for the automation of part-turn valves. Major representatives of this type are butterfly valves and ball valves. The basic requirements on part-turn actuators are described in the standard EN ISO 5211. Less than one full revolution usually means a swivel movement of 90deg; however, there are some valve types requiring a different swing angle, such as two-way valves. The closing elements in part-turn actuators are always supported by the valve housing, i.e. the weight of the closing element does not act upon the part-turn actuator. This is expressed in the second sentence of the definition. Part-turn valves diameters range from a few inches to several metres. The torque requirement for operating the closing element has a comparable range from approximately 10 N m to several 100,000 N m. Electric actuators are unrivalled for large-diameter valves with high torque requirements.