Butterfly valves
Butterfly valve are the most specified valve type for moderate-duty conditions in pipe sizes of two inches and larger. Their reduced weight, reliable bubble-tight shut-off, ease of operation and automation allowed them to displace gate valves in traditional applications. Bi-directions shut-off is one of the hallmarks of butterfly valves. Continuing development of the butterfly valve is making it possible to use them in aggressive applications that previously were the exclusive domain of gate and globe valves
One of the most compact and light-weight valves
now available. Used for a wide range of applications, the choice of seat, lining
and disc options has increased significantly over recent years making the valve
a popular choice. A wide range of materials, sizes and pressure ratings gives
reliable positive isolation and moderate flow control capability over a wide
range of applications throughout the industry. The metal seated valve is well
established in petrochemical and oil industries being lightweight, firesafe and
suitable for actuation. Butterfly valves offer a number of advantages
when used for the proper application. They may be used in a wide variety of
chemical services, they are available with small dimensions allowing for use in
areas where space is limited, and they allow a high coefficient of flow.
Butterfly valves are quick opening valves that consist of a metal
circular disc or vane with its pivot axes at right angles to the direction of
flow in the pipe, which when rotated on a shaft, seals against seats in the
valve body. They are normally used as throttling valves to control flow. Unlike
ball valves, butterfly valves do not have any pockets in which fluids may
become trapped when the valve is closed.