Friedrich. Lassig invented the rings at the 1880s, but it wasn't until the 1910s that he got the Zhuanli. Because of a simple cylindrical tube with a aspect ratio of 1:1, the liquid moves through thousands of channels formed by rings, covering the inner and outer surfaces and eventually flowing to the bottom. The gas entering the bottom will flow through the same path formed by the ring and have time to come into contact with the liquid and react. Main Features: Metal Tower packing is made of carbon steel, stainless steel or aluminum alloy, with thin-walled, heat-resistant, large gap, high flux, low resistance and other characteristics, application scope: especially suitable for vacuum distillation column, heat-sensitive, easy to decompose, a material liable to polymerize and carbon build-up