| 摘要 |
PCT No. PCT/IL96/00109 Sec. 371 Date Jul. 8, 1998 Sec. 102(e) Date Jul. 8, 1998 PCT Filed Sep. 12, 1996 PCT Pub. No. WO97/14898 PCT Pub. Date Apr. 24, 1997In-line control valve constructions are described which include a piston-type valve assembly and a plurality of control chambers (C1,C2,C3,C4) controlled via one or more controls ports (CP1, CP2) to provide a normally-open valve may be closed by controlling the fluid pressure applied to the control port (CP1, CP2), or a normally-closed valve which may be opened by controlling the fluid pressure applied to the control port (CP1,CP2). Also described are valves which have a balanced construction and which therefore include relatively small actuators for opening and closing the valve.
|
