[RASMB] Elevated temperature operation with a turbomoledcular pump.

[Nourse, Amanda]

Dear Walter and RASMB-ers

 

We are definitely interested in implementing this improvement.

 

Regards

 

Amanda

 

___________________________________________________

Amanda Nourse (PhD)

Section Leader: Molecular Interactions Analysis

Hartwell Center for Bioinformatics and Biotechnology

St. Jude Children's Research Hospital

332 N. Lauderdale St.

Mail Stop 312

Memphis, TN 38105 USA

901-495-4845 (W)

901-495-2945 (Fax)

 

 

________________________________

From: rasmb-admin at server1.bbri.org [mailto:rasmb-admin at server1.bbri.org]
On Behalf Of Walter Stafford
Sent: Friday, March 11, 2005 11:18 AM
To: rasmb at server1.bbri.org
Subject: [RASMB] Elevated temperature operation with a turbomoledcular
pump.

 

Dear RASMB-ers

 

        I have been testing a turbomolecular pump as a replacement for
the standard diffusion pump on the XL-I. I am writing to report the
results of that experiment.

 

On my machine, with the standard diffusion pump installed, I have not
been able to run above about 23 degrees without having serious fogging
of the interference condensing lens after about 15 minutes, making it
impossible to take data.

 

About a month ago, with the help of the Beckman Serviceman and folks
from the Axiden Division of Alcatel Vacuum Technology
{http://www.adixen-usa.com/}, we installed an ATP80 TMP in place of the
diffusion pump. Other than a flange that had to be machined to mate the
TMP to the diffusion pump flange, it was a direct replacement. The
original rough pump was used to back up the TMP.  see:
{http://www.adixen.com/all/dyn/products/products.php?id_prod=20&lg=us}

 

So far the results have been quite remarkable. After the first test of
running for 4 days at 40 degrees, the optics were clean. The chamber was
actually cleaner after the run than before. The TMP seemed to have
removed all the residual oil that we were unable to remove after
replacing the diffusion pump. It pumps down to 3-5 micons in less than 5
minutes and ultimately to about 1-2 microns. The fringe patterns seem to
be more stable (not sure exactly why, but I was informed that the
regular diffusion pump heater normally cycles on and off; the flexing
associated with that may explain it).

 

We use it routinely now for all runs and couldn't be happier with it.

 

Several labs have expressed an interest in installing one on their
machines.

 

However, Beckman will not support the pump or provide one as standard
equipment unless there is sufficient interest. A proper, Murphy-proof
installation would require a firmware change and field service support
to allow it to be included under the service contract and warranty.

 

I would like to take a survey of those who might be interested, so that
we can convey that expression of interest to Beckman.

 

If you have an interest and think that running at higher than 20 degrees
or higher precision might be useful to you, please respond to this email
by replying to the RASMB. I'll collect the responses and comments and
forward them to the folks at Beckman.

 

It has opened new vistas for our research.

 

Thanks

Walter

-- 

########################################################################

Walter F. Stafford III, Ph.D.

Analytical Ultracentrifugation Research Laboratory
Senior Scientist
Boston Biomedical Research Institute
64 Grove Street
Watertown, MA  02472-2829

main:(617) 926-8040
tel: (617) 658-7808
fax: (617) 972-1753

mailto:stafford at bbri.org

http://www.bbri.org/faculty/stafford/Stafford.html

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