Modified butterfly valve and assembly

Abstract

Butterfly valves of this invention generally comprise a flapper element that is rotatably disposed within an annular bore of a valve housing. The valve may be configured to provide an improved degree of gas flow control sensitivity from a closed to a partially opened position through the use of projections that extend radially inwardly from the housing bore, are positioned at diametrically opposed positions within the bore, and that are specifically configured to provide a gradual increase in gas flow across the valve as the flapper is moved from a closed position to a partially opened position. The butterfly valve may be configured having further projections that extend radially inwardly a distance therein, that are positioned at diametrically opposed positions in the bore, and that include faces that are sized and shaped to cooperate with respective opposed surfaces of the flapper to seal off gas flow within the bore when the flapper is placed into a closed position. The butterfly valve may also be configured having a bushing that surrounds a shaft that is mounted to the flapper. The shaft extends through the housing and is coupled to an arm outside of the housing. The bushing and arm are configured having complementary surfaces to provide a seal therebetween that functions to minimize or eliminate the unwanted leakage of gas from the valve.

Dependencies are inferred from the claim text.