Pigs are not only used to clean pipelines, they are also used when the product inside the pipeline changes. Displacement pigs provide a physical separation between the product in front of the pig and the product behind the pig. By using these displacement pigs TECCURO can quickly and efficiently:
- Replace the air inside a pipeline by nitrogen;
- Perform ethylene displacements at lower pressures;
- Filling pipelines air free with water for hydrostatic testing.
Foam and mandrel pigs used for cleaning can also be used during displacements. A commonly used mandrel pig is the Bi-directional (Bi-Di) pig. This tool consists out of disks that will seal the pipeline off but enables the pig to move in both directions. Other disks will guide the pig through the pipeline. These pigs can be modified depending on the challenges. Seal disks, for example, can be replaced by cup disks or extra seal disks be placed to make sure that two products will not mix.
Besides the conventional pigs, there are also gel pigs. The viscosity of these pigs is determined by the chemical components that are put together. However, the operation of these pigs is identical to the traditional displacement pigs. The big difference is that the viscosity of the gel pig can be adjusted. This property allows the pig to be made more solid or liquid in composition. Liquid gel pigs can be pumped more easily and bypass instrumentation & valves. Something that is not possible with normal pigs. Gel pigs also have the ability to clean a pipeline in addition to their displacement properties.