Butterfly valve having cartridge construction with improved bearings

Abstract

A butterfly valve is provided having a disc adapted to be rotated between an open and a closed position. A valve seat made of resilient material is adapted to engage the disc in the closed position. The valve seat has an outer wall surrounding the disc and has an aperture therein. A shaft has one end affixed to the disc and extends outwardly through the aperture. A ring surrounds the valve seat and is permanently affixed thereto for preventing deformation of the outer wall of the valve seat. The ring is made of a material that is much stronger and more rigid than the valve seat and includes a cylindrical lip defining an aperture in the ring. This aperture is in line with the aperture in the valve seat wall with the lip projecting into the aperture in the valve seat wall. A cylindrical collar surrounds the shaft and is positioned within the cylindrical lip and supported thereby. The collar provides a bearing surface for the shaft. The valve seat further includes a pair of flanges on the axial ends thereof projecting outward from the outer wall. The ring is positioned between the flanges and spaced therefrom creating a pair of grooves, one groove being on each side of the ring. The disc, the valve seat, the shaft, and the ring form a unitary valve assembly. A housing is provided including two sections, each section including a pair of projections on the inner surface thereof for mating with the pair of grooves. The sections are joined and cooperate with the ring and the outer wall of the valve seat to hold the unitary valve assembly within the housing.