Eyelid hybrid butterfly type poppet valve

Claim 1

In a butterfly poppet valve of the type employing a valve poppet pivoted from an axially, in-line, closed position with respect to a valve seat formed within a tubular valve housing, to a valve open position at some angle thereto, the improvement comprising: a semi-spherical pocket formed within said housing generally exterior of the axial flow path through said housing, an ''''eyelid'''' type poppet valve disc having a surface facing said pocket of similar configuration to that of said pocket, a shaft including an eccentric portion extending through said housing at right angles to the axis thereof and intersecting the center of curvature of said pocket, means defining a circular valve seat opening within said housing to one side of said shaft, a bridge spanning the width of said valve seat opening, means fixing said valve disc to said bridge for movement into valve closing position, links pivotably coupled to said bridge on respective sides with openings therein receiving said shaft eccentric portion, the length of said links and the radial dimensions of said disk and said bridge relative to said shaft axis being such that rotation of said shaft and said links in unison causes swinging of said bridge and said disc angularly away from said circular valve seat and into position within said pocket and generally outside the flow path upon full opening of said valve.