| 摘要 |
PCT No. PCT/GB86/00278 Sec. 371 Date Jan. 21, 1987 Sec. 102(e) Date Jan. 21, 1987 PCT Filed May 19, 1986 PCT Pub. No. WO86/06931 PCT Pub. Date Dec. 4, 1986.A flow control valve in which a moisture expansible body (18) is adapted to close a bleed valve (24) shutting off a bleed from an inlet chamber (2) through a by-pass (12) to the underside of a thrust plate (9) operatively coupled by a rod (9) to a valve member (26) arranged to close communication between the inlet (2) and an outlet (4) chamber. On absorption of moisture, the body (18) expands to drive thrust rod (21) downwards to close the bleed valve (24) whereby pressure under the thrust plate (9) is relieved and inlet water pressure closes valve member (26) to cut off discharge. On drying the body (18) shrinks relieving thrust rod pressure on the valve (24) which opens under inlet pressure and pressure liquid is bled through passages (25) and the by-pass (12) to drive the thrust plate (9) upwards to open valve member (26) and allow liquid flow from the inlet (2) to the outlet (4) chamber and to discharge (5). The expansible body (18) may be moistened by ambient moisture or controlled wetting may take place by a bleed (14) from the outlet chamber (4) leading via an adjustable throttle valve (15) into an apertured casing (17) containing the body (18) of expansible material. |
