Those “things” near bottom of the spinning band distillation column are called bellows. They function as a flexible expansion joint. Glass is normally anything but flexible and these bellows are engineered to allow the expansion and contraction over the length of the column.
Distillations start at room temperature and goes up to the distillation temperature when boiling starts. The inner glass wall of the distillation column lengthens due to the rise in temperature. The bellows allow the outer wall of the distillation column to lengthen along with the inner column. Without the bellows the distillation column would be under stress during distillations and prone to breaking.
The longer the distillation column the more bellows are needed.