PTFE pall ring is developed on the basis of the PTFE raschig ring, It is to open one or two layers of rectangular holes in the sidewall,and the base material of the holes is not out of the sidewall but forms inward bending of blade.The same size of Pall ring and Raschig ring have the same surface area and porosity,but the pall ring’s holes on its sidewall can flow gas-liquid so that the ring inner surface will be took full advantage.