[RASMB] turbo-molecular pumps in Beckman XLA XLI

[John Philo]

Arthur, FYI my XL-I drive (with ~30 billion revolutions) seems definitely to
have started leaking drive oil over the last year or so. Thus the
turbomolecular pumps will apparently not fix all the oil issues. Fortunately
this oil mostly accumulates on the circuit boards below the removable bottom
plate, and at least when running at 20-25 C isn't a big problem for the
optics. Note too that my XL-A with similar revs still leaks no noticeable
drive oil, so this issue does vary from one drive to another.
 
John
  _____  

From: rasmb-bounces at list.rasmb.org [mailto:rasmb-bounces at list.rasmb.org] On
Behalf Of Arthur Rowe
Sent: Friday, April 12, 2013 10:43 AM
To: Laue, Thomas
Cc: RASMB
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
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