Tips for Troubleshooting Your Centrifugal Evaporator

Written By: LabX.com

Jun 22, 2022

By Holden Galusha

While centrifugal evaporators are generally robust, reliable pieces of equipment, their design means they may be afflicted by the same problems that both rotary evaporators and benchtop centrifuges experience, such as weak vacuums and unstable spinning. Here are three problems that you may experience with your centrifugal evaporator, as well as troubleshooting steps for each.

Problem 1: Weak vacuum

There are three main culprits of a poor vacuum: contaminated oil, faulty gaskets or tubes, and mechanical problems inside the pump. If your evaporation processes are hindered by a weak vacuum, troubleshoot it to find the root cause with the following steps:

Change the vacuum pump oil and run the evaporator again. If the vacuum is stronger, then you’ve eliminated the root problem of contaminated oil. If the vacuum is still weak, then proceed to the next step.
Clean the lid gasket with an aqueous-based cleaning solution. Depending on the acidity of your samples, it’s possible that grime has built up on your gasket and compromises the seal when the lid is closed. Make sure not to use an acidic cleaning agent as that could erode the gasket, worsening the problem.
After cleaning the gasket, run the evaporator again and see if the problem persists. If so, try replacing the vacuum hose. Assuming the new vacuum hose does not help, it is a safe bet that the vacuum pump is malfunctioning. In this case, your options are to either (1) have the pump rebuilt by a qualified service technician or (2) order a new pump.

Problem 2: Evaporator doesn’t spin properly

If your centrifugal evaporator is not spinning properly (e.g., vibrates or makes odd noises), the first thing you should do is ensure that the rotor is balanced. While modern centrifuges have imbalance detectors built in that, theoretically, will terminate an unbalanced run automatically, the situation can quickly become dangerous if the detector fails. As such, you should always make sure that the rotor is balanced yourself.

If you are sure the rotor is balanced but the evaporator still is not working properly, examine its physical stability. Is it sitting on a flat, sturdy bench or does the bench wobble? Maybe one of the evaporator’s feet was broken while you were moving it. You may have to move the evaporator to a different bench or replace its feet.

Finally, you may need to replace the motor brushes if your concentrator has a brushed motor. Worn brushes can’t maintain the electrical connection needed for the centrifugal evaporator to spin correctly, resulting in performance issues. While it’s certainly possible to replace worn brushes on your own, it may be best for you to hire a qualified service technician.

Problem 3: Evaporator doesn’t heat samples effectively

Unless the issue is merely a dead infrared heating bulb that you can replace, you will not be able to repair heating problems on your own. Contact the OEM to send a field service technician out to fix your evaporator.