PIG (Pipeline Inspection Gauge) is an internal cleaning - the inside of the pipe from all solid or liquid dirt (whether wax, debris, scale, mud or wood). In the sense of all materials that are considered to be able to inhibit the flow of fluid or damage the inside of the pipe) by scraping or swabbing using a "Pig".
Pigging pipe cleaner is a Pipeline Inspection Gauge (PIG), scraper, or often also called a "pig" in the context of piping engineering. Pigging is the process of cleaning or maintaining the internal pipe using a special tool (pig/scraper) that is driven by fluid flow. www.partconveyor.co