Butterfly valves are low-pressure
valves of efficient design which are used to control and regulate flow. They
are characterized by fast operation and low pressure drop. They require only a
quarter-turn from closed to full open position. Butterfly valves are available
with metal-to-metal seats, soft seats and with fully lined body and disk. The
soft seats permit bubble-tight shut off and the full lining enhances erosion
and corrosion resistance.
Butterfly Valve consists of a
disc that rotates on a shaft at right angles to the fluid flow. When open, the
disc is edge-on to the flow and the fluid passes around it, offering limited
resistance. In the closed position, the disc is rotated against a seat in the
body of the valve.
Butterfly valves usually take up
little more room than a pair of pipe flanges, and are therefore an attractive
alternative to the ball valve where space is limited. In fact, some butterfly
valves are designed specifically for insertion between pipe flanges, these are
known as wafer butterfly valves.
Available seat materials include:
- Bune N
- Neoprene
- Fluorel
- Hypalon
- EPDM