Manual Actuators
Manual Actuators are used in applications that require a throttling type of control valve that can be manually operated and set. Capable of giving precise manual throttling control, these actuators can be used on nearly all standard globe-style or angle-style valve body assemblies. A travel indicator on the actuator yoke can provide a visual indication of valve plug position.
Manual actuation is done by a human driving force.While the manual actuation can be made directly on the axis of the valve through a handwheel or other devices, manufacturers refer to manual actuator as incorporating a manual Gearboxes, a mechanism that provides greater torque based on more turns.In fact, it is normal to couple gearboxes in electric or Pneumatic Actuators to increase their features, or at least supplement them with a manual driver in case of failure of the main source.
Manual actuation is usually drove by handwheels. Valves whose access location makes difficult to operate on them can be drove by chain wheels. For security, the driver can be out of the gearbox spigot. And then, only authorized operators who bring the handwheel or wrench nut with them can operate the valve.