Valves are used heavily in industrial processes for regulating the flow of gases and liquids by opening or closing certain pathways and hatches. There are various types of valves used and each type has a specific purpose. Butterfly valves are typically used in large pipes and cisterns to control the flow of liquids.
A butterfly valve is very simple in design which doesn’t resemble a butterfly. It comprises of a flat, plate-like structure in the centre of a pipe. An iron or steel spindle passes through the plate and it is connected to a handle to the exterior of the pipe. When you rotate the handle you can alternately switch-off or turn-on the flow of the liquid. The handle can be turned by hand or electric motor. This kind of a valve has a very sturdy design.
These valves offer a near-infinite range of flow settings and they have very few moving parts. The housing or body of the valve can be either of the two main types which are lug or wafer. Lug bodies consist of lugs that protrude and provide bolt holes that match the ones in the pipe flange, while wafer bodies have no lugs. The disk is the operable part of the valve and the flow of the liquid or gas is controlled directly due to the movement of the disk within the valve body. The spindle, which is also known as the stem, is the potion of the valve that transfers incremental force to the disk. The seat of the butterfly valve houses the seal that stops the flow of the liquid or gas through the valve.
Butterfly valves come in a wide variety of diameters from 1 inch to over 200 inches. They are used extensively in industrial applications where large pipes are used to transport liquids over distances and a constant degree of pressure must be maintained as they can stand up to very high pressures of over 700 psi. They can also be designed for very high temperatures of up to 1,000 degrees Fahrenheit.
Butterfly valves are lightweight, fairly inexpensive and are relatively easy to install.