A Raschig ring is a piece of tube, approximately equal in length and diameter, used in large numbers as a packed bed within columns for distillations and other chemical engineering processes. They are usually ceramic, metal, or glass and provide a large surface area within the volume of the column for interaction between liquid and gas vapours.
Raschig rings are named after their inventor, German chemist Friedrich Raschig,[1][2] who patented them in 1914.[3][4]