US Patent 10138697 Mineral extraction system having multi-barrier lock screw

A dual barrier lock screw for a wellhead assembly is provided that includes a first seal disposed at a first axial location along the body of the screw and a second seal disposed at a second axial location along the body of the screw, wherein the first and second axial locations are different from one another. The screw may also include a passage extending axially through the body of the screw and coupled to a port at the end of the screw. The port is configured to receive external pressure and allow testing of the dual barrier seals of the lock screws. A system that includes the lock screw and methods of operating and testing the lock screw are also provided.