| 摘要 |
A dual discharge valve for immersion in fluid, in a cistern includes a housing having an upper portion and a lower portion. An upwardly movable main valve assembly within the housing forms therewith a variable volume upper chamber and lower chamber. A first vent means is between the upper and lower chambers and an outlet leads down from the lower housing portion, which portion contains a seat for the main valve assembly at the entry to the outlet so that in the lowered position of the main valve assembly the outlet is blocked against the ingress of fluid. A central stem extends upwardly from the main valve assembly and is actuable by a first operating means remotely from the upper housing to raise the main valve assembly off its seat, the wall of the lower portion of the housing above the seat having apertures. On raising the main valve assembly immersion fluid can enter the outlet, the net upward force thereby causing it to rise to the top of the upper chamber and permit full flow of the immersion fluid through the outlet. A second operating means is actuable remotely from the upper housing, to separately raise the main valve assembly off its seat and then exert a downward force on the main valve assembly, so that at a predetermined intermediate water level, the main valve assembly re-seats.
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