| 摘要 |
1,194,070. Valves. J. L. POWER. 24 Sept., 1968 [25 Sept., 1967], No. 45415/68. Heading F2V. A valve closure member 19 is held open, to permit water to flow from a mains inlet 6 to an irrigation outlet 7, whilst a predetermined volume of water is being dispensed, and during this time a piston 20 is reciprocated in cylinder 3 by water bled from the stream passing to outlet 7, which piston is arranged at each stroke to step a ratchet wheel 42 to a position in which the wheel and an associated piston 25 is freed to move to the right so admitting continuous mains pressure to cylinder 3 through conduit 26 so causing piston 20 to seat closure member 19, and cut off the supply to outlet 7. The piston is reciprocated by alternately connecting mains pressure to conduits 26, 22 by means of a slide valve 28 carried by a rod 5 which has a lost motion connection with piston rod 31. A catch 33, which latches piston 20 in its lowest position in which closure member 19 is seated, is automatically released when wheel 42 is moved to the left again to start another cycle. This wheel is carried on a piston rod 99 spring urged to the right and carrying a projection 37 which co-operates with a slot (38, Fig. 4, not shown) in a time calibrated plate 41 against which a pointer 39 can be set after first pushing projection 37 through slot (38). When the ratchet wheel has been stepped back to zero by a pawl (43, Fig. 3, not shown) movable by piston 20, the projection is re-aligned with slot (38) to permit wheel 42 and piston 25 to move to the right. In a modification (not shown) piston 20 is replaced by a flexible diaphragm. |
