Chromatography Forum

Hello All;

The turbopump on one of our systems was not able to reach above 10% and it was shutting down after about 5 minutes. After a lenghty investigation, it was detemined that our turbopump had gone bad. I sent the turbopump to Pfeiffer for repair and they told me that they fixed a bad seal and sent it back. I installed the pump back, but I still have the same problem!

I appreciate any suggestions.

Thank you.

I guess you already have thoroughly checked for leaks

Does your rough pump get the pressure low enough? A weak rough pump will give the same symptom.

Hello Steve:

The rough pump is working fine. I took a similar system and connected it to the same rough pump and it works perfectly.

Are you sure there isn't a big leak somewhere such as the side plate o-ring or vent valve. Both need periodic light applications of Apiezon L vacuum grease. Otherwise I assume Pfieffer tested it before sending it back, so perhaps the controller is bad.

Hello MSCHemist:

Pfeiffer had tested the controller as well and it had looked good. You are correct that we may have a big leak from the side plate or the vent valve (I had a craked interface on this system a few yaers ago). I will check them and let you know what I find.

Thank you very much for the suggestion

System has been under vacuum for about two hours now and there are no leaks. I plugged the transferline and pumped down for about 10 minutes. I still have vacuum!