It’s an item that isn’t well known outside of the industries that use pipelines to move their products, but within them, polyurethane pipeline pigs—or “Poly Pigs” as they are often called—are an essential part of their operations. With slightly oversized diameters, the pigs can remove all sorts of debris, such as loose sediment, product buildup, and foreign matter, to help increase a pipeline’s carrying capacity and improve product quality.
Types of Pipeline Pigs
Available in several styles (wiping, drying, or scraping) and sizes, these internal pipe cleaners have the flexibility to navigate ells, tees, short radius bends, and multi-dimensional piping—all without interrupting the flow of the product in the pipeline. And polyurethane pipeline pigs are invaluable in a wide variety of applications including petrochemical, oil & gas transmission, municipal systems, pulp and paper, and process piping systems.
How do pipeline pigs work?
The pig is inserted into a launching station, which is an oversized section of the pipeline. The station is then closed, and the flow of the product pushes the pig through the pipe, taking any built-up debris with it. The flexibility of the polyurethane allows the pig to negotiate complex pipeline geometries and smaller diameter pipelines. Once the pig reaches the receiving station–or “pig catcher”– it is removed.
What are the benefits for the pipeline industry?
Companies that use polyurethane pipeline pigs save on power costs since clean lines reduce the pump pressure. Those that use their pipelines for multiple products will see one of the most significant benefits: no need for extensive line flushing at the end of each product transfer. They can clear out the entire contents of the pipeline, saving a considerable amount of product.
And without the need to flush the lines, poly pigs provide the added benefit of rapid and reliable product changeover. Sampling the product at the end point is faster with pigs. That’s because the distinction between the products is clear. The old method of checking at intervals to determine if the product is meeting specifications takes considerably longer.
One other advantage that pipeline pigs have to offer is an environmental one. Formerly, when operators would flush a line to ensure that a product was cleared entirely from it, they would use a cleaning agent that would then need to be subjected to effluent treatment or solvent recovery. This problem is eliminated because of the precise boundaries between products that are made possible by pipeline pigs.