Index:
[thread]
[date]
[subject]
[author]
From: Arthur Rowe <arthur.rowe@nottingham.ac.uk>
To : rasmb@alpha.bbri.org
Date: Tue, 20 Mar 2001 10:29:52 +0000
Re: no more lamp cleaning - the basic problem . .
> THIS MESSAGE IS IN MIME FORMAT. Since your mail reader does not understand
this format, some or all of this message may not be legible.
--MS_Mac_OE_3067928993_4486166_MIME_Part
Content-type: text/plain; charset="US-ASCII"
Content-transfer-encoding: 7bit
. . . which is, of course that lamps get dirty. Why ? Because of the
residual oil vapours in the chamber, which are there because of the problems
inherent in a simple, non-cryo-trapped 2-stage (RP + DP) pumping system.
But why - I have wondered for years - do we put up with so crude a system ?
Some of you may recall my years of experience with electron microscopy,
where cleanliness is of the essence, and this sort of oil contamination is
anathema. OK - I can see that the economics of putting the fancier pumping
systems of EMs into an AUC would not make sense. But why on earth do AUCs
never have turbomolecular pumps instead of those dreadful diffusion pumps ?
Having worked in the past with turbo pumps and built same into new kit, I
have to say they are marvellous - clean, no warm-up time, no danger of
oxidised oil from air getting in. Their use in EMs has been limited by the
need for ultra-level freedom from vibration, but that's not an AUC problem,
and the simpler turbo pumps are not expensive.
So can somebody (Beckman, other . . ) tell me - why do we not use turbo
pumps in AUCs instead of dirty old diffusion pumps ?
Greetings to all
Arthur
*****************************************************
Arthur J Rowe
Professor of Biomolecular Technology
University of Nottingham
School of Biological Sciences
Sutton Bonington
Leicestershire LE12 5RD UK
Phone/voicemail +44 (0)115 951 6156
Phone/fax +44 (0)115 951 6156/7
email arthur.rowe@nottingham.ac.uk
arthur.rowe@connectfree.co.uk
Web http://www.nottingham.ac.uk/ncmh/business
*****************************************************
--MS_Mac_OE_3067928993_4486166_MIME_Part
Content-type: text/html; charset="US-ASCII"
Content-transfer-encoding: quoted-printable
<HTML>
<HEAD>
<TITLE>Re: no more lamp cleaning - the basic problem . . </TITLE>
</HEAD>
<BODY BGCOLOR=3D"#FFFFFF">
<FONT SIZE=3D"2">. . . which is, of course that lamps get dirty. Why ? Becau=
se of the residual oil vapours in the chamber, which are there because of th=
e problems inherent in a simple, non-cryo-trapped 2-stage (RP + DP) pumping =
system.<BR>
<BR>
But why - I have wondered for years - do we put up with so crude a system ?=
Some of you may recall my years of experience with electron microscopy, wh=
ere cleanliness is of the essence, and this sort of oil contamination is ana=
thema. OK - I can see that the economics of putting the fancier pumping syst=
ems of EMs into an AUC would not make sense. But why on earth do AUCs never =
have turbomolecular pumps instead of those dreadful diffusion pumps ? Havin=
g worked in the past with turbo pumps and built same into new kit, I have to=
say they are marvellous - clean, no warm-up time, no danger of oxidised oil=
from air getting in. Their use in EMs has been limited by the need for ult=
ra-level freedom from vibration, but that's not an AUC problem, and the simp=
ler turbo pumps are not expensive.<BR>
<BR>
So can somebody (Beckman, other . . ) tell me - why do we not use turbo pum=
ps in AUCs instead of dirty old diffusion pumps ?<BR>
<BR>
Greetings to all<BR>
Arthur<BR>
*****************************************************<BR>
Arthur J Rowe<BR>
Professor of Biomolecular Technology<BR>
University of Nottingham<BR>
School of Biological Sciences<BR>
Sutton Bonington<BR>
Leicestershire LE12 5RD UK<BR>
<BR>
Phone/voicemail +44 (0)115 951 6156<BR>
Phone/fax +44 (0)115 951 6156/7<BR>
email arthur.rowe@nottingham.ac.uk<BR>
arthur.rowe@connectfree.co.uk<BR>
Web http://www.nottingham.ac.uk/ncmh/business<BR>
*****************************************************<BR>
</FONT>
</BODY>
</HTML>
--MS_Mac_OE_3067928993_4486166_MIME_Part--
Index:
[thread]
[date]
[subject]
[author]