Ball valve construction

Claim 1

A valve comprising a body formed with aligned pipe-attaching hubs at downstream and upstream ends thereof, a ported ball between said hubs rotatable within said body between open and closed positions, a stem for turning said ball between open and closed positions, said stem rotatable in said body about an axis transverse to the common axis of said hubs, said ball formed with a slot receiving the inner end of said stem, said slot enlarged to permit movement of said ball relative to said stem in a direction longitudinal of said body when said ball is in closed position, an annular upstream seal recessed into said body adjacent said upstream hub adapted to seal against said ball, a rotatable annular member reciprocable longitudinally within said body adjacent said downstream hub and having at its inner end an annular downstream member shaped to engage said ball to move said ball longitudinally into sealing engagement with said upstream seal against the pressure upstream of said valve, a rotatable member within said body engaging said annular member for rotating said annular member, said rotatable member and said annular member being relatively axially slidable, said annular member being in threaded engagement with said body, whereby said annular member reciprocates within said body when turned by said actuating means, said actuating means having a worm with an external turning knob, said rotatable member having a worm wheel meshing with said worm.