US Patent 6971633 Rotatable seal for ball valve

A ball valve assembly having two end bodies selectively detachable from each other with each end body defining a fluid conveying bore is provided. A rotatable ball valve element is disposed within the end bodies and defines a central passage having an axis, with the rotatable ball valve element having an open position in which the central passage is aligned with the fluid conveying bores and a closed position in which the passage is not aligned with the fluid conveying bores. The ball valve assembly also includes a pair of seals, with a seal disposed in each end body and in selective abutting engagement with the rotatable ball valve element. The structure of the rotatable ball valve element is controlled such that the ball valve assembly is assembled with the ball in an open position, thereby substantially eliminating the significant force normally required for assembly of the ball valve assembly.