Butterfly valves are typically used to isolate or regulate the flow of water. There are three main types of butterfly valves: concentric, double eccentric, and triple eccentric. The concentric butterfly valve usually has a rubber seat with a metal disc.
A double eccentric, or high performance butterfly valve, can have a variety of materials for the seat and disc. A triple eccentric butterfly valve, also known as triple offset butterfly valve, can be made with either a laminated or solid metal seat design. The triple offset valve design are used solely in applications that require bi-directional shut-off, such as in oil and gas, chemical factories, and ship building.