Plastic butterfly valves - a good return on investment in many applications

For metal and plastic piping systems in applications with a maximum medium pressure of 10 bar, it is more difficult to select the appropriate materials for butterfly valves than for ball valves or diaphragm valves. But-terfly valves in plastic piping systems, which are of the same material as the piping system, face strong com-petition from metal butterfly valves. In the latter, the parts which come into contact with the medium are coated; they are either of stainless steel or have elastomer liners. The liner has a sealing function in the pas-sage and to the exterior and also protects the metal from the medium.