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5 tube balancing argument

Andy Phillips andy.phillips at bbsrc.ac.uk
Fri Oct 11 03:02:33 EST 1996

Lou Cantolupo wrote:
> Well, I took it upon myself to call the centrifuge experts, Beckman.
> Their response:
> [stuff deleted]
> HOWEVER.  In an ultra centrifuge, where you routinely approach speeds in
> excess of 80,000 rpm (as in CsCl grad's), it is imperetive that you fill
> all slots with equal weights.  In ultra, where the rotor tolerance is
> 5/10,000 of an inch in the eliptical orbit, equal vector forces prove
> not to be so equal unless they are 100% equal.  In otherwords, when you
> go fast, the rules can't be bent as easily; you have to optimize your
> orbit.

If Beckman feel that it's imperative that you fill all 8 slots of an 
ultracentrifuge rotor, it's a pity they don't mention this in their 
manuals. I have several Beckman rotor manuals and catalogues that 
specifically descibe how to arrange tubes symmetrically if not all the 
slots are to be used.

 Email  : andy.phillips at bbsrc.ac.uk  : University of Bristol
 Home   : andy at cycad.demon.co.uk     : IACR Long Ashton Research Station 
 Phone  : +44-1275-549257            : Long Ashton
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 WWW    : http://www.lars.bbsrc.ac.uk/plantsci/molbiol/andy.html

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