Patent ID: 6499716
Filing Date: 2002-12-31
Classification: F16K

Abstract:
A flush valve including a body having an inlet and an outlet, a valve seat at said outlet, a piston assembly movable in said body toward and away from said valve seat to control flow from said inlet through said outlet, a pressure chamber in said body above said piston assembly and normally maintaining said piston assembly closed upon said valve seat, said piston assembly including a refill orifice connecting said chamber with said body inlet,a relief valve in said piston assembly for venting said chamber to said outlet, means for opening said relief valve to vent said chamber causing said piston assembly to move away from said valve seat to open flow through said outlet, said piston assembly including a guide and a piston attached thereto, a seal having an annular perimeter portion between facing surfaces of said guide and piston, said seal having an annular interior portion positioned to form a seal with said relief valve, and a plurality of spaced ribs integral with and connecting said seal perimeter portion, spaces between said ribs, with each space having a circumferential extent greater than the circumferential width of a rib to permit relative movement between said seal perimeter portion and said seal interior portion.