What is the function of glass thorn in the thorn fractionator?

Condensation reflux or condensation distillation of liquids with boiling point higher than 140 degrees Celsius. The glass spike in the spiral fractionator has the function of condensing reflux or condensing and distilling liquid with boiling point higher than 140 degrees Celsius. Webster's fractionator, also known as Thorne fractionator. It is a fractionation tube with a group of downward inclined spinous processes at intervals, and each group of spinous processes is arranged in a spiral shape.