Butterfly valves are manufactured in two or three way configurations. It has a wafer shaped body with a thin, rotating disc closing device. Like the ball valve, the butterfly valve operates with a one-quarter turn to go full open to close. The disc is always in the flow but the disc is thin and offers little flow restriction. The three-way butterfly valve is designed as a liquid coolant control valve. This valve diverts flow from a single inlet (Port A) to two outlet ports (B & C). Another model is designed as an air control valve. This valve directs flow from two inlets (parts B & C) to a single outlet (port A). The two butterfly elements are mounted onto a common shaft, allowing a single motor to actuate the valve. The outlet ports are configured to operate inversely (i.e. port B opens as port C closes). The brushless DC motor allows for fine servo control of flow between port B and C. The valve can be used as a diverting valve (on/off) function, or as a mixing valve (modulating function).