Tune-able Vacuum for Chemical Applications - filtrations and volatile solvent evaporations - rotovaps, concentrators, & vacuum ovens. Achieve precise vacuum control for organic evaporations with Welch's Advanced Vapor Management (AVM). Choose from six dry PTFE vacuum pump models with flows up to 70 L / min and adjustable vacuum down to 2 Torr. Economical DryFastTM vacuum pumps are perfect for tough lab applications.