摘要 |
A piston assembly for use in a flush valve for operating toilets and urinals, with the flush valve having a body having an inlet and an outlet and a valve seat at the outlet. The piston assembly is movable in the body toward and away from the valve seat to control flow from the inlet through the outlet. There is a relief valve in the piston assembly for venting a flush valve pressure chamber to the flush valve outlet. The piston assembly has an outwardly directed lip seal which bears against an interior wall of the body, with the lip seal being held between facing elements of the piston assembly. The lip seal includes an insert and an elastomer overlying and substantially enclosing the insert. Both the elastomer and the insert have portions extending toward the flush valve body wall and the insert has support elements which are in contact with the facing elements of the piston assembly to take the load from such elements off of the elastomer body of the lip seal.
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