AW: [RASMB] 6-channel centerpieces

[Claus Urbanke]

Hi Mircea,


We do simlar what you describe routinely although we have the special
housings available.  The differences are:

We use old single sector housings (using ds ones should work as well)
We tighten the cell with the lower window, the centerpiece with the flat
side pointing upwards and finally a spacer for 3 mm centerpieces instead of
the upper window to 100 inchpounds, then use a filling hole screw to set the
tightened centerpiece (you may need only one of them) and then loosen the
setup again to remove the 3mm centerpiece spacer.
After filling, we put in the upper window, gasket and everything to complete
the cell. Tighten to 100 Inchpounds again, remove the set screw from the
filling hole and then tighten the cell to the desired torque (usually 130).

We found it important to fix the 6Ch centerpiece with the filling hole
screw. Sometimes you have to work a bit to get the spacer out again and that
would move the centerpiece.


Why do we not use the special centerpieces? Very simple, we use the old
Beckman ModelE torque stand. An another reason, our special equilibrium
centerpieces ruined some of our window holders with the steel liners wearing
off aluminum from the window holder.


Good luck

Claus



Claus Urbanke
Medical School Hannover
Biophysical Chemistry OE 8830
D-30625 Hannover
Germany



-----Ursprüngliche Nachricht-----
Von: rasmb-bounces at rasmb.bbri.org [mailto:rasmb-bounces at rasmb.bbri.org] Im
Auftrag von Rasa, M.V
Gesendet: Dienstag, 13. Dezember 2005 15:01
An: rasmb at rasmb.bbri.org
Betreff: [RASMB] 6-channel centerpieces


Dear colleagues,

We have the opportunuity to use 6-channel centerpieces for aqueous
solutions, but we don't have the special housings described in the manual. I
think(?) that it is O.K. to use
the 2-channel housings by tightening the cell to 60 inch-pounds, screwing
it, removing the upper window, filling the channels, and finally tightening
it to 120-140 inch-pounds.
I think(?) that the protruding side
of the centerpiece should be upwards. Have you tried that?

On the other hand, since the channels are quite small, should we expect
problems with analysis because of (maybe) too narrow equilibrium profiles?

Thanks,

Mircea.

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