Abstract

An improvement in a launcher for launching spheroid pigs one at a time into a pipeline, having a downward sloping barrel magazine for holding a multiplicity of spheroid pigs and having a closable fluid tight opening for loading the pigs on the breech end and a full bore opening valve on the muzzle end in fluid communication with a pipeline, is characterized by apparatus situated in the barrel magazine upstream of the full bore valve for releasing the pigs one at a time into the pipeline from the magazine. The releasing apparatus of the improvement comprises:(a) a shaft means passing sealably through the wall of the magazine,(b) on the exterior of the magazine, a means affixed to the shaft for turning the shaft radially along its long axis, and(c) affixed to the shaft on the interior of the magazine, a catcher-releaser having a convexoid surface adjacent to the end of the shaft and a concavoid surface opposite the convexoid surface, the catcher-releaser being truncated parallel to the long axis of the shaft,such that rotation of the shaft through 365° will catch and release a single spheroid pig.