The Re-Emergence of Spherical Pigs

摘要

Many years ago spherical pigs were commonly used in natural gas pipelines to remove liquids - mostly water and condensates. The launchers were designed to only handle spherical pigs, using special valves such as the Wheatley Launch Valve and the Fitzpatrick Launch Valve. These resembled a check valve and were designed to release one spherical pig at a time by movement clapper with a lever.