Pig launchers are essentially vessels used for launching of a pipe pig or a pig tool into the pipeline for cleaning or inspection purpose. After being launched into the pipeline, the pig tool is pushed through the pipeline by a driving fluid. The pipeline is cleaned along the way by brushing action from the pig. On the other end the pig tool is received by a pig receiver.
Pig receiver is also a vessel used for receiving the pipe pig tool. Pig launchers and receivers are designed to meet the specific requirements of a pipeline.