Introduction of Butterfly Valve Actuation Method
Butterfly valves can be operated manually with handles and gears, or automatically with electric, pneumatic, or hydraulic actuators. Electric actuators turn the valve using an electric motor, while pneumatic actuators use compressed air and hydraulic actuators use hydraulic pressure. Depending on the manufacturer, manual butterfly valve actuation may also be available using a hand lever, gearbox, sprocket, or chain drive.
Manual actuation
Manual actuation is considered an economic and inexpensive method. In addition, it is easy to operate.

Hand Lever: Applicable to small valve size and is capable of being locked into a position of opened, partially opened or closed.

Gear: These are designed for slightly larger valve size and utilize a gearbox to increase torque at the expense of decreased speed of opening or closing. Gear operated valves are self-locking and it can be equipped with position indicators.
Automatic actuation
Automatic actuation is a reliable method of controlling valves from a remote location. The actuators make rapid operation of larger valves possible. Actuators can be designed to fail-open (stay opened in case of actuator failure), fail-close (stay closed in case of actuator failure) and often come with a manual actuation method in case of any failures.

Electric: Uses an electric motor to control the valve by turning the valve stem.

Pneumatic: Requires compressed air to move a diaphragm or piston to control the valve.
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