[RASMB] condensation

[Borries Demeler]

> 
> Dear All,
> 
> We're having a serious problem with our XL-I.  The UV filter that is  
> positioned over the condenser lens is fogging with oil every time it  
> is used.  It is the underside of the filter that gets fogged.   
> Fogging, of course, completely negates our ability to use the  
> interference optics.  A Beckman service rep recently changed the  
> condenser lens and also replaced our vacuum pump.  Does anyone have  
> any notion of why this fogging is occurring and what the fix might  
> be?  Our service rep is trying hard to get this fixed, but he is new  
> to the analytical centrifuges.  Any help the community can offer  
> would be greatly appreciated.
> 
> Chad

Hi Chad,

oil condensation seems to be a common problem with the XLA/I. In my experience
this problem is minimized when running at lower temperature, and aggravated
when running at temps higher than 25C. I think the only surefire solution
is to replace the pump with a turbomolecular pump. You may want to check
with Walter Stafford, I believe he has made such a retrofit to his machine.

Regards, -Borries