Fluid flow isolation/regulation valve

Claim 1

A valve including A. a valve body, B. said valve body having i. a valve seat, ii. an inlet section and iii. a discharge section, C. said inlet section having means providing a bore terminating at a port at the valve seat, D. said discharge section having means providing a bore starting at a port at said valve seat, E. said ports being in alignment, F. said valve seat being of frustoconical configuration, G. said valve body having a first circular opening extending upwardly from and having a diameter at least equal to the larger diameter end of said valve seat, said first opening being above the tops of said bores, H. said valve body having a second circular opening extending downwardly from and having a diameter no larger than the smaller diameter end of said valve seat, said second opening being below the bottoms of said bores, I. a valve stem rotatable in said valve body for regulating the flow of liquid from the bore of said inlet section to the bore of said discharge section, J. said valve stem including a flow control element rotatable in said valve seat, i. said flow control element having opposed parallel first and second flat Surfaces which are identical to and in registry with one another, ii. said first and second surfaces being of identical trapezoidal condiguration, iii. the configuration of the side edges of the flow control element matching the configuration of said valve seat, K. said valve stem having a tapered flange above said flow control element the configuration of which matches the configuration of the valve seat above the tops of the ports, L. said valve stem having a frustoconical lower head below the flow control element the configuration of which matches the configuration of the valve seat below the bottoms of the ports, M. said valve stem having an upper valve head extending upwardly from the tapered flange of said flow control element, i. the diameter of said upper valve head being smaller than that of the first circular opening, N. said valve stem having a circular post extending downwardly from the smaller diameter end of said lower head, i. the diameter of said post being smaller than that of the second circular opening, O. first annular groove means on said upper valve head, P. a first annular O-ring in said first annular groove means, i. said first O-ring sealingly engaging said first circular opening, Q. a second annular groove means on said post, R. a second annular O-ring in said second annular groove means, i. said second O-ring sealingly engaging said second circular opening, S. means for rotating said valve stem, and T. means for pulling said valve stem downwardly into said valve seat so that said tapered flange and frustoconical lower head engage said valve seat above the tops of said posts and below the bottoms of said posts.