Random column packing

Originally the packing material consisted of glass spheres, however in 1850 they were replaced by a more porous pumice stone and pieces of coke.

Raschig rings are usually made of ceramic or metals, and they provide a large surface area within the column, allowing for interaction between liquid and gas vapors.

Lessing rings have partitions insides which increase the surface area and enhance mass transfer efficiency.

The cross structure of the Pall ring makes it mechanically robust and suitable for use in deep packed beds.

They are made of stainless steel mesh, giving Dixon rings a low pressure drop and after pre-wetting.