Picking The Controller That Meets A Lab’s Needs

Vacuum pumps play a role in many lab applications, and sometimes it helps to automatically control this piece of equipment. “Any application where someone is trying to separate components of a mixture in a precise and repeatable way is a good candidate for an automatically controlled pump,” says Scott Leahy, director of technical marketing at VACUUBRAND (Essex, CT). One of the most common applications of automatically controlled vacuum pumps is rotary evaporation. They also are handy with distillation columns, fluid aspiration, and vacuum ovens.

Improving efficiency
Adding automation delivers many advantages. “An automatically controlled pump used with a rotavap, an oven, or with a distillation column gives you the ability to evaporate—or distill—one component at a time, maximize yields, and minimize process times,” Leahy explains. The advantages extend to a range of applications. With fluid aspiration used with cell culture, for instance, controlling the vacuum keeps the suction consistent when changing media. As Leahy notes, “Low adherent cells can be aspirated away, and work consequently lost, if too much suction is applied.” (As someone who has worked with lots of cell cultures, I ruined many with too much suction—starting with a culture dish of healthy cells and ending with nothing. Automatic control could have saved me an enormous amount of grief !)

Features to find
In looking for an automatic controller for an existing vacuum pump, the first priority is compatibility. “Make sure the material in the controller and the flow path are compatible, so it holds up,” says Roland Anderson, laboratory products manager at KNF Neuberger
(Trenton, NJ). The controller must also match the required parameters of an application, such as the required level of vacuum and the pump’s flow. Then a user must decide between a two-point controller, which is basically on or off, or an adaptive controller, which adjusts the speed of the pump to match the current needs of an application. “An adaptive controller only works with a speed-controllable pump,” Anderson notes. “A two-point controller is somewhat less expensive
and a little older technology.” With rotary evaporation, for example, an adaptive controller prevents bumping, or violent boiling. Bumping can waste some of the sample. As with other equipment in a lab, scientists want a vacuum pump to be easy to use. “Under ideal circumstances, you want a pump that simply requires you to hit the start button, and then it runs your process to completion,” Leahy points out. “You don’t want to have to go through a complicated setup or
programming procedure or to have to look back at the controller in order to watch over the process to be sure it is still proceeding as you would expect.”

Minimizing maintenance
Adding an automatic controller can reduce pump maintenance. Pumps that automatically adjust the motor speed usually run at much less than full speed, Anderson notes. The lower speed makes a pump quieter and reduces wear. “Since the noise level and maintenance requirements
are two of the top concerns among vacuum-pump users,” Leahy adds, “it is worthwhile to keep in mind that using speed-controlled pumps helps to address both of these concerns.” Also, the controller itself needs only minimal care. “If you’re pulling wet vapor through it, maybe clean it at some point,” Anderson says, “but it usually won’t require maintenance.” So, adding a controller makes vacuum pumping easier to use and more effective, all without much trouble.

by Mike May, PhD

Mike May is a freelance writer and editor living in Texas.
You may reach him at mike@techtyper.com.

First published in Lab Manager magazine’s December 2017 issue.