摘要 |
A valve device (1) which includes a fluid inlet (4) a fluid outlet (5), a main valve seat (32) defining an aperture through which fluid may selectively flow from said inlet (4) to said outlet (5), a valve assembly (31), movable relative to said main valve seat (32) between an open position of said valve in which fluid may flow from said inlet (4) to said outlet (5), and, a closed position of said valve in which fluid flow is prevented, a control chamber (12), at least a portion of the wall of which is formed by said valve assembly (31), such that the volume of said control chamber (12) is variable depending upon the position of said valve assembly (31), a fluid passageway (7), providing fluid communications between said fluid inlet (4) and said control chamber (12). |