Valve operator embodying time-delayed closing means

Claim 1

Flush valve means comprising in combination a. a hollow vessel adapted to be disposed internally of a flush tank of a plumbing fixture, said vessel being configured with an open bottom adapted to be disposed at an elevation intermediate the levels of water in the tank when filled with water and when drained, b. an enclosed passage means opening into the upper portion of said vessel, c. an air valve for controlling flow of air through said passage means comprising time-delay release means configured with an expandable chamber into which air is received from said vessel and provided with a flexible diaphragm biasable in response to differential pressure thereacross, a bleed orificE through which air is discharged to atmosphere, and bias loading means for biasing said chamber to unexpanded configuration, said air valve being closed when unactuated and with no pressure differential across said diaphragm, d. means for actuating said air valve, e. a bouyant member disposed to extend upward into said vessel, said buoyant member being configured to be sealably seated upon a drain opening in the flush tank by pneumatic force created in said vessel by water rising in the flush tank trapping air in said vessel providing super-atmospheric pressure equal to the hydrostatic head differential between levels of water within and without said vessel in the flush tank, said fixture being operably flushed by said air valve being actuated enabling air of super-atmospheric pressure within said vessel to escape thereby enabling said buoyant member to be water-borne and rise in said vessel from seating contact with a drain opening, said buoyant member being again seated by gravity when water is evacuated from the tank.