turbo pump broken?

[cdicken]

Hi folks ....

today I tested a used turbopump build by a local manufacturer. I connected the roughing pump and reached 10microns. Then I switched on the turbo ... it started spinning up and the pressure dropped into submicron scale .. then I heard a kind of screetching inside the turbo for an short time, but it was still working and the pressure dropping. While spinning further up, the screetching intervalls came more often and got louder and longer, so I shut down the turbo. Loosing speed, the screetching got weaker and finally vanished.

I have no experience with turbos, but I guess its the bearings? The pump wasnt in use for about a year, but as far as I know was in good condition. Unfortunately it was not covered and the inlet lay open, so maybe it is only some dirt inside the rotor/stator housing?

Chris

[Carl Willis]

Chris,

Pumps with magnetic bearings can sometimes make unpleasant noises if they aren't perfectly aligned. Most often the noises are intermittent, only encountered when the pump is spinning up / down, and don't signal any problems with function. If you have a mag-lev pump, I'd say see if it spins up and the noise stops. If the noise continues during operation, you probably need to have it re-balanced at a qualified repair shop or it may have further problems.

If your pump has non-magnetic bearings, the sound is an unqualified bad sign.

-Carl

[cdicken]

Carl, thanks for you reply ...

I really dont know whether the pump has magnetic bearings or not. Is there a way to check without dismounting the device?

As a first hint, it was a rather cheap and small model ... I think, magnetic bearings are not cheap!

Chris

[Carl Willis]

Well, for starters, what is the make and model?

[cdicken]

Manufacturer is Ilmvac GmbH, Germany ... very local distributer as I said Its an OEM model used I a small highvac system, build in the 90s, so there is no more information on the net. Type- and serialnumber cant be seen without dismounting...

[Tom Dressel]

You might try talking to "Jersey" at A J Vacuum services. They rebuilt my turbo and controller.and are very helpful.

http://www.ajvs.com/

Tom

[cdicken]

Hi Thomas,

thanks for your answer, but I am living in germany However, the turbo was not my own (universities stuff), I was just testing this pump as there was need for one on a laboratory course experiment. But it seems the guy must go ahead with his diff a bit longer ...

CHris