Introduction to Butterfly Valves

A butterfly valve is a quarter-turn rotational motion valve used to start, stop, and regulate flow. It is named for the disc that rotates like a butterfly’s wings to control fluid passage. These valves are widely used in industrial applications due to their compact design, fast operation, and cost-effectiveness.

How It Works

• The valve consists of a circular disc mounted on a rotating shaft.

• When the valve is open, the disc is turned parallel to the flow.

• When closed, the disc is rotated perpendicular to the flow, blocking it.

• Operated manually (via handle or gear), pneumatically, or electrically.

Key Features

• Quick Operation: Only a 90° turn needed to open or close.

• Lightweight & Compact: Requires less space and support than gate or globe valves.

• Low Cost: Economical for large-diameter applications.

• Good Flow Control: Suitable for both on/off and throttling services.

Limitations

• Not Ideal for Full Throttling: May cause vibration or cavitation.

• Disc Obstruction: Disc remains in the flow path even when open.

Less Tight Shutoff: Compared to ball or globe valves in some designs.