Valve

Claim 1

A valve comprising: (a) a valve body having walls defining a tapered conical bore and bore axis, said bore having large and small axial end openings and opposed inlet and outlet openings, said inlet and outlet openings arranged about a flow axis substantially perpendicular to the bore axis, (b) a tapered cage comprising conical interior and exterior surfaces, said exterior surface sized to abut the conical bore of the valve body, said cage being designed for easy replacement, said cage having opposed openings that open, at least in part, upon the opposed inlet and outlet openings, (c) a stopper arranged to turn on an axis aligned with the bore axis and arranged within the cage and having, as a limiting exterior configuration, a conical surface that abuts the interior conical surface of the cage, said stopper having a control vane extending radially outward from the stopper axis, said vane having opposed edges arranged to abut the interior conical surface of the cage at all points on a first sealing plane including the bore axis, said stopper comprising larger and smaller conical plugs at each axial end of the control vane, said conical plugs having edges arranged to abut the interior conical surface of the cage at all points on second and third sealing planes perpendicular to the bore axis where they intersect the interior conical surface, said stopper having a drive stem extending axially away from the one conical plug and a balancing stem extending axially away from the other conical plug. (d) a bonnet fixed relative to the valve body for closing of an axial end of the conical bore while permitting the drive stem to pass therethrough, (e) cap means for closing the axial end of the conical bore opposite the bonnet means, (f) biasing means for urging the stopper toward the small end of the conical bore, (g) means for rotating the stopper fixedly secured to the stem emerging from the bonnet, and (h) means comprising a cam surface and cam follower for lifting the stopper axially away from the small end of the conical bore a controlled distance when it is rotated away from a closed position where the control vane is substantially perpendicular to the flow axis.