PIPELINE COUPLING

摘要

A coupling for making a pressure tight, threaded connection with two axially aligned plain end pipe joints is disclosed. The coupling comprises a tubular member having internal screw threads adjacent opposite ends of the tubular member. The threads form a spiral groove in the outer surface of each of two aligned plain end pipe joints upon relative rotation between the pipe and the coupling to form threaded connections with the pipe joints when the coupling is rotated relative to the pipe joints. The coupling configured as a swivel union can also be used to connect a new section in a pipeline in place of a damaged section.