The vacuum system used with rotary evaporators can be as simple as a water aspirator with a trap immersed in a cold bath (for non-toxic solvents), or as complex as a regulated mechanical vacuum pump with refrigerated trap.

The main components of a rotary evaporator are:
A motor unit that rotates the evaporation flask.
A heated fluid bath (generally water) to heat the sample.
A condenser or 2-3 condensers with either a coil passing coolant, or a "cold finger" into which coolant mixtures such as dry ice and acetone are placed.
A receiving flask at the bottom of the condenser, to catch the distilling solvent after it re-condenses.