From: Sandy Go <sandygo@uhnres.utoronto.ca>
  To  : rasmb@alpha.bbri.org
  Date: Tue, 27 Mar 2001 14:35:03 -0500

broken windows

    Has anyone had any problems with broken windows?  Lately I have been
having some problems with frequent window breakages.  I have lowered the
torquing pressure to about 90 in-lb, so I know it is not an over
torquing problem.  Breaking or cracking of the windows usually happen
just after I take out the cell from the torque stand.  I wonder if
frequent use eventually leads to the centerpiece warping so it does not
lie flat anymore.  Do these parts i.e., the cell housing, centerpiece,
quartz windows, and window holders, have a certain lifespan?  We have
had the instrument for three years now and we run about 125 cells worth
of samples per year.  We typically run samples between 20k to 48k rpm.
We have never replaced any of the parts except for the windows and the
disposables (window liners and gaskets and a few screw rings).  Please
help ASAP.  Thanks.

Sandy Go
Research Technician
OCI/Princess Margaret Hospital
University of Toronto