[RASMB] condensation

[Walter Stafford]

Hi Chad,

I am not sure but I think the freight will around $8K installed by 
Beckman. It may have gone up, tho. I am very happy with the TMP. We can 
do equilibrium runs at 40 degrees for days on end without any condensation.

Walter

Chad Brautigam wrote:
> Hi, Borries,
>
> The condensation has been occurring during 20 deg. C runs.  We have 
> rarely had problems with condensation using this temperature in the 
> past.  Recently, before this problem came up, a user did a run at 37 
> deg. C, and there was definitely condensation on the filter after that 
> run.  I wasn't surprised by that, but I am surprised by the consistent 
> fogging that we are now getting at 20 deg. C.
>
> Would anyone like to comment on the cost of a turbomolecular pump?
>
> Chad
>
> On Jun 4, 2008, at 12:30 PM, Borries Demeler wrote:
>
>>>
>>> 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
>> _______________________________________________
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>> RASMB at rasmb.bbri.org
>> http://rasmb.bbri.org/mailman/listinfo/rasmb
>
> ======================================
> Chad A. Brautigam, Ph.D.
> Assistant Professor
> Department of Biochemistry
> The University of Texas
> Southwestern Medical Center at Dallas
> Department of Biochemistry
> 5323 Harry Hines Blvd.
> Dallas, TX 75390-8816
> Office:  214-645-6384
> Fax:  214-645-6353
> Email:  chad.brautigam at utsouthwestern.edu
>
>
>
>
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-- 
Walter F. Stafford, Ph.D.
Senior Scientist
Analytical Ultracentrifugation Research Laboratory
Boston Biomedical Research Institute
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Watertown, MA 02472-2829
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