Wiki上关于pig的解释中,其中一条是:
(engineering) A device for cleaning or inspecting the inside of an oil or gas pipeline, or for separating different substances within the pipeline. Named for the pig-like squealing noise made by their progress. 参见http://en.wiktionary.org/wiki/pig
粗译:(工程领域)一种用于清理或者检测油气管道设备,或用于分隔管道内不同的介质。因其在操作过程中产生类似于猪的振鸣声而得名。