| 摘要 |
A timer in which the re-filling of a control chamber (26) via its inlet (56) causes displacement of a resilient wall (34). A surface (62) of the wall (34) thus engages a valve seat (64) to shut-off the inlet (14) of the timer from its outlet (20). To open the timer a cap (88) is depressed. A stem (90) depending from the cap depresses an element (44) against the action of a spring (60). The element (44) is thus displaced to open the outlet bore (42) of the chamber (26). Water pressure in the casing (12) acting on the wall (34) then urges it in the direction which separates the surface (62) from the seat (64). A series of stop surfaces (86) co-operate with a stop element (100) of the cap (88). The surfaces (86) are at different heights. The distance through which the cap (88) can be depressed is varied by rotating it so that the element (100) co-operates with a selected surface (86).
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