Inerting

This operation involving the replacement of a reactive atmosphere (oxidizing, flammable, explosive) or simply ambient air with an inert gas.

Scale (carbon deposit)

When brazing tubular circuits, inerting replaces the air in the pipes with an inert gas.
This prevents oxidation of the internal surfaces, which is characterized by a deposit of iron oxides known as scale (cabon deposit).
This abrasive deposit could be hazardous to the proper operation of components connected to the pipes, so it’s important to prevent it from forming.