How Many Turns to Close A Butterfly Valve

Manual butterfly valve

Most manual butterfly valves are closed by rotating the handle or stem, and usually require 2 to 3 turns to fully close. The principle is to change the diameter state by rotating the butterfly plate by about 90° (i.e., a quarter turn), but due to the design of the transmission structure (such as worm gear), the actual operation requires multiple turns.

Clockwise rotation of the handle is the closing direction, and counterclockwise rotation is the opening direction.

‌Handle butterfly valve‌: The butterfly valve is opened and closed by turning the handle. There is a toothed disc between the handle and the valve body, and the range of motion of the handle on the toothed disc is between 0~90°. When the handle is in a vertical position with the pipeline, the valve is closed; when the handle is parallel to the pipeline, the valve is open.

‌Worm gear butterfly valve‌: The opening and closing of the butterfly valve is controlled by turning the handwheel on the worm gear head. Rotating the handwheel clockwise can close the butterfly valve, and rotating it counterclockwise can open it.

 

Special or large butterfly valves

 

Very few special scenarios (such as large industrial valves or complex transmission systems) may require thousands of turns of operation. For example, the search results mentioned that a valve needs to be rotated 8,000 times, but such situations are usually not related to butterfly valves, and are more likely to involve design anomalies of gate valves or other types of valves.

 

Electric butterfly valve

If an electric actuator is used, the closing speed depends on the motor speed (commonly 12~48 rpm, special designs can reach more than 100 rpm)‌8. However, this parameter only affects the closing time and has nothing to do with the number of rotations of manual operation.

 

Pneumatic butterfly valve

It usually takes 200 to 600 turns to close a butterfly valve. The operating specifications of pneumatic quick-cut butterfly valves point out that the number of opening and closing turns should not be too many, and large-diameter valves should also complete the opening and closing operations within 200-600 turns.