Patent ID: 6648013
Filing Date: 2003-11-18
Classification: F16K,Y10T

Abstract:
A valve assembly for use in a fluid system having fluid flow therethrough, said valve assembly comprising:a mounting member having a front surface, a rear surface and a passage therethrough, said mounting member positionable within the fluid system; a flapper pivotably carried by said mounting member, said flapper having a front surface and a rear surface, said flapper having an open position and a closed position, wherein said flapper blocks fluid flow through said passage of said mounting member when said flapper is in said closed position; a cam member defining a cam surface carried by said rear surface of said flapper, said cam member having a hump formed thereon; a follower carried by said mounting member, said follower dimensioned to engage said cam member and slide thereon, wherein the fluid flow must be at a predetermined minimum pressure on said front surface of said flapper to allow said follower to initially overcome said hump of said cam member thus allowing said flapper to pivot to said open position; and wherein said cam surface is configured to cause a closure force exerted on said flapper by said follower to be greater when said flapper is in said closed position than when said flapper is in said open position.