Semibalanced plug valve

Claim 1

In a semibalanced valve, comprising a valve seat, a plug having a tapered bottom surface which is characterized to minimize turbulence in a fluid which is adapted to flow through the valve and thereby to provide a higher flow efficiency, said characterized tapered surface having an annular seating surface extending outwardly therefrom, said plug being operably positioned for rapid movement between a fully opened and fully closed position with respect to said seat to control the flow of the fluid passing through the valve, an annular grooved-out recess formed in a circumferential part of the tapered surface of the plug, spaced apart passageways positioned to pass said fluid from the top of the plug into said recess portion upon the flow of the said fluid over said tapered surface, said annular grooved-out recess being operable to create a vacuum effect on the said fluid that will cause the said fluid in a space above the top of said plug to be rapidly pulled through said passageways to a space below the bottom surface of the plug and a rapid neutralization to take place between the pressures of the fluid acting on the top and bottom surfaces respectively of the semibalanced plug and wherein a first portion of each passageway extends through a part of the annular grooved-out recess and the remaining portion extends through an adjacent portion of the tapered bottom surface of the plug.