3 way solenoid valves have three pipe connections and two orifices (when one is open, the other is closed, and vice versa). These popular valves are commonly used to alternately apply pressure to and exhaust pressure from the diaphragm operator of a control valve, single-acting cylinder, or rotary actuator. pilot solenoid valve is available in normally closed and normally open constructions. diaphragm poppet valves suitable for controlling air, inert gas, and liquids,internal piloting controls large orifices to provide high flows .