A regulating valve that may be activated for fine control are Cast Iron Butterfly Valve. This is so named because the valve seating is made up of a disc that revolves around a stem in the middle. This valve is designed to keep a seal against pressure coming from both directions and stop backflow in systems intended for one-way flow. Cast Iron Butterfly Valveis possible to disconnect from either side without affecting the connections on the other side. This design creates a tight seal.