Manual, two-step or adaptive control? Vacuum regulation makes it possible to optimize the vacuum level in the system. An optimum vacuum level reduces evaporation times and ensures a better product yield. Controlling the vacuum also reduces the build-up of oscillation and improves solvent recovery and reproducibility.
Manual vacuum control uses a stopcock or a manual valve and the vacuum level is adjusted by sight. With this method, the whole process must be closely monitored as the level of vacuum required can change during evaporation.
Two-step or on/off vacuum control makes it possible to switch the vacuum in the system back and forth between a high and a low setpoint by turning the pump on and off. This method means that the process can be left to run unsupervised once the minimum and maximum limits have been set.
Adaptive vacuum regulation delivers the best results in terms of separation, speed and solvent recovery, and also means that the process can be left to run unsupervised after configuration of the settings. This control method changes the rotational speed of the pump automatically and adjusts it to meet the process requirements exactly. It is also the most precise method, enabling the system to work with a particular vacuum level and simultaneously react to changing conditions with no need for the operator to monitor and adjust the settings.
Although it is relatively easy to find the right pump for rotary evaporators, we recommend getting the advice of experts. They can ensure that special applications and individual processes are also considered.
Based on How to Select a Pump for Rotary Evaporation, The Pump Post, 2014
An ideal overall system for rotary evaporation