From: Philo, John <jphilo@amgen.com>
  To  : 'rasmb@bbri.harvard.edu' <rasmb@bbri.harvard.edu>
  Date: Thu, 20 Nov 1997 08:04:32 -0800

RE: cell leakage

Marcus,

In my experience the 3 mm centerpieces are indeed more difficult to
seal, but I have actually been able to take them to 60K (although they
do sometimes leak at high speed).  

First, I recommend tightening the screw rings to 130-135 inch pounds.  I
think that by itself will be enough to get you sealed up to 42K.

Second, at the higher speeds you may need to use some grease to help
keep a seal.  Many people in the field rub their finger along the side
of their nose and use this 'nose grease' for this purpose.  What I do is
to apply a very light coating of Dow Corning silicone vacuum grease to
the centerpiece.

'Hope this helps,

John Philo

>----------
>From:
>	marcus@Nemesis.chemie.uni-stuttgart.de[SMTP:marcus@Nemesis.chemie.uni-stuttg
>art.de]
>Sent: 	November 20, 1997 10:16 AM
>To: 	rasmb@bbri.harvard.edu
>Subject: 	cell leakage
>
>I got problems with a 3 mm double-sector centerpiece (Epon, charcoal-filled).
>At 20000 rpm or more cell leakage occures. Does anybody know how to prevent
>this? I tourqued the screw ring to 120 inch-pounds as usual. With the 12 mm
>double-sector centerpieces I got no problems up to 42000 rpm.
>
>
>MARCUS WAGNER
>
>you may also reply to
>marcus@medusa.chemie.uni-stuttgart.de
>