[RASMB] turbo-molecular pumps in Beckman XLA XLI

[David Hayes]

Hi all,

Initial observations from a few experiments after installing the turbo pump at Walter's lab:

1.  The turbo pump seems to clean the system slowly of any oil.  It took about a week before optics were really clean at 37 C.
2.  The crude temperature system on the XLA/I can be a complicating factor.  If you put a room temperature rotor in a system, then set the target temperature to 37 C, while the system is heating the rotor, the outside can temperature can reach 50 C or so and this almost always makes the drive oil come out.  I tested with an equilibrium method heating a rotor 1 degree an hour from 25 to 37 and no drive oil came out.  The better solution was to get an incubator and pre-heat the rotors to 37 before placing in the centrifuge.

All of our current XLA/I's at Boehringer have turbo pumps now, and we run at 20 C all the time, but occasionally see oil in the can which is presumed to come from the drive.

David Hayes


________________________________
 From: Arthur Rowe <arthur.rowe at nottingham.ac.uk>
To: "Laue, Thomas" <Tom.Laue at unh.edu> 
Cc: David Hayes <drdavidbhayes at yahoo.com>; RASMB <rasmb at rasmb.org> 
Sent: Friday, April 12, 2013 1:42 PM
Subject: Re: [RASMB] turbo-molecular pumps in Beckman XLA XLI
 


Hi all

I warmly endorse the praise for the work put in by Walter (2005 onwards)  in both getting a turbo pump working in an XLI/A instruments - and in getting Beckman to take this idea seriously.

I recall that I had little success in the latter area when I tried in 2004. As I posted on RASMB (April 7th 2004):

"The problem with oil in the XL-I/A is a notorious and intractable one.
Having a turbo pump instead of that horrible 'straight through, unvalved' DP
system sounds very easy to do, and I have long contemplated doing it. After
all, you can get compatible flanges, I am sure. And as a long-time electron
microscopist and builder of ancillary equipment I just shudder at the
crudity of AUC vacuum systems. However - such discussions as I have had with Beckman people suggest that
this approach (using a turbo) would help but not really solve the oil
problem, which is at least partially due to oil from the drive shaft of the
motor, not just to oil from blowback from the DP."
I wonder if the story which Beckman gave me in 2004 about leakage of oil vapour from the drive shaft of the motor was other than a 'smoke screen' for inaction? Or is there really oil leaking in that location?

Arthur

Professor Arthur J Rowe
NCMH/Food Sciences
University of Nottingham
Sutton Bonington
Leics LE12 5RD UK

Tel: +44 115 9516156
arthur.rowe at nottingham.ac.uk


On 12 Apr 2013, at 16:52, Laue, Thomas wrote:

Here, here!
>Tom
>
>
>________________________________
>
>From: rasmb-bounces at list.rasmb.org [rasmb-bounces at list.rasmb.org] on behalf of David Hayes [drdavidbhayes at yahoo.com]
>Sent: Friday, April 12, 2013 11:44 AM
>To: RASMB
>Subject: [RASMB] turbo-molecular pumps in Beckman XLA XLI
>
>
>Hi all,
>
>
>Just wanted to write a public thank-you note to Walter Stafford for pioneering hardware work to get Beckman to put in turbomolecular pumps in their analytical ultracentrifuges.  We recently had an install of a new XLA and found out that even the XLA's come with turbo pumps standard.  This made me wonder if Beckman ever wrote a thankyou letter to Walter for pioneering this hardware improvement, which thought led me to write a thank you letter to Walter for this and also for all the years managing and contributing to the RASMB list for biophysics scientists.
>
>
>David Hayes_______________________________________________
>RASMB mailing list
>RASMB at list.rasmb.org
>http://list.rasmb.org/listinfo.cgi/rasmb-rasmb.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.rasmb.org/pipermail/rasmb-rasmb.org/attachments/20130412/40b2be59/attachment.htm>