A valve device comprising a first fluid port (101), a second fluid port (121), a valve seat (119) defining an aperture through which fluid may flow from said first port to said second port, a valve member (107), moveable relative to said valve seat between a seated position and a lifted position. A control chamber (103) is formed at least in part by said valve member, having a first passageway (102) communicating between said control chamber and said first port, and a second passageway (106) communicating between said control chamber and said second port. A control valve (117, 112) is associated with at least one of said passageways to permit fluid flow therethrough, and to thereby urge said valve member into either said seated or lifted position. A restrictor or flow control element (104) is also provided.