Butterfly Valves - continued.

Here are the key features of butterfly valves:

a. In the full open position, the disc remains in the way of the fluid flowpath. But the disc is designed to create as little obstruction as possible.

b. In the full close position, the butterfly valves usually do not provide a shutoff which is as secure as that provided by a gate valve. However, we should note that the good quality butterfly valves are provided with circumferential disc seats to provide adequate shutoff.

c. These valves are inexpensive compared to the other designs.

d. A relatively large amount of force is required to use these valves in flow regulation service. But still, in many cases these valves are used for flow regulation service.

e. These valves can handle large flows (in large diameter pipes) easily.

f. Inexpensive to maintain.