Rotary Evaporator Product

Overview

A rotary evaporator removes a solvent from a sample gently, by boiling it off under reduced pressure at a temperature low enough to leave heat-sensitive compounds intact. It is standard equipment in synthetic chemistry and natural-product labs, where the last step of a workup is almost always "rotovap it down" to recover a dissolved product as a residue or oil. Two tricks make it work: the flask spins to spread the liquid into a thin, fast-evaporating film, and the system runs under vacuum so the solvent boils far below its normal point. Rotating ethanol off at 40 °C under vacuum, for instance, would otherwise need close to 80 °C at atmospheric pressure.

The instrument is a marriage of a small machine and a glass distillation train: a motor, a heated bath, and a lift on the mechanical side, feeding a borosilicate flask-condenser-receiver set on the glass side.

How it works

The sample sits in the Evaporating Flask, clipped to the Rotation Drive. A brushless motor spins the flask at a set speed through a reduction gear; centrifugal force films the liquid up the flask wall so a large surface is always presented to evaporate. The lower part of the flask dips into the Heating Bath, a stainless pan of water or silicone oil warmed by a tubular element. An NTC probe holds the bath at setpoint, and a thermal fuse cuts power if it ever runs dry.

Vacuum is the other half. The Vacuum System connects an external pump and lets the operator pull the pressure down while a gauge reads it; the lower the pressure, the lower the boiling point, so evaporation stays gentle. Solvent vapor leaves the flask through the Glassware Set train — up the vapor duct, into the chilled coil condenser, where it recondenses and drips into the receiving flask. The rotating joint is sealed against the static condenser by a PTFE Vapor Seal, the one component that has to both spin and hold vacuum.

At the end of a run the Motorized Lift raises the whole head on a ball screw to pull the flask clear of the hot bath, and the Control Board coordinates speed, bath temperature, and the lift while the operator works from the Display & Keypad.