Steel Mandrel Pig
Definition - What does Steel Mandrel Pig mean?
A steel mandrel pig is a type of pipeline cleaning device. As its name suggests, a steel mandrel pig is made out of steel with steel mandrels on its outside diameter. The pig is made with longevity in mind, as the steel mandrel itself is very durable. Typically only the softer components of a steel mandrel pig, such as brushes, are replaced.
A steel mandrel pig is made to clean the inside wall of a pipeline. If a pipeline is allowed to collect too much debris while transporting fluids, then the debris can create clogs or lead to other types of pipeline failures.
Corrosionpedia explains Steel Mandrel Pig
During the cleaning process, a steel mandrel pig is inserted into the pipeline through a section known as a pig launcher. With the opening and closing of several valves on the pipeline and on the pig launcher, the pig is allowed to enter a section of the pipeline. As it travels through the pipeline, brushes or other devices attached to the pig are used to collect any debris in the pipeline. Through some more valve work, the pig is fed into the pig catcher, which is another section of pipeline intended to collect the steel mandrel pig and the debris it accumulated along the way.
A steel mandrel pig can be used for other reasons besides cleaning. Batching, a process in which multiple products are sequentially transported through a pipeline, can be performed with steel mandrel pigs. A combination of special polymer cups and discs are outfitted on a pig, making it suitable for batching by creating a seal between the different products. These specially outfitted steel mandrel pigs create a seal that can also be used to displace any residual product or water in the pipeline.