US Patent 8220488 Flow control valve with internal isolation means

A combination valve assembly comprises an inner valve nested within an outer valve. The outer valve comprises a housing and a closure, permitting full closure of the valve assembly. The inner valve comprises a housing and a closure, permitting flow control by the inner valve within requiring movement of the outer valve. The housing of the inner valve is keyed to the outer valve closure, so that movement of the outer valve closure rotates the inner valve housing and closure simultaneously.