| 摘要 |
A fluid discharge device, primarily for w.c. cisterns, has a housing (4, 9) with an outlet (5) through the base of the cistern (1). A main valve assembly (20) with a seal (21) normally blocks this outlet (5). A substantially closed variable volume chamber (26) is formed in the housing (4, 9), the main valve assembly (20) providing its base. A pilot valve (12, 30, 36), controllable externally of the cistern, can open this chamber (26) to the outlet, and there is a restricted passage (10, 49, 58, 88) between the chamber (26) and the interior of the cistern (1). On opening the pilot valve, water (and sometimes air under pressure) escaping the chamber (26) alters the pressure balance and the main valve assembly (2) lifts to generate the full discharge. The flow of water can help keep this valve assembly (20) lifted, and a low pressure zone in the discharge passage can be used to keep the chamber (26) scavenged. The valves close when the discharge is completed, and replenishment water penetrates the chamber (26) via the restricted passage (10, 49, 58, 88). <IMAGE> |
