[DIYbio] Re: ultracentrifuge

On Feb 29, 9:13 pm, Richard Proctor <richardmproc...@gmail.com> wrote:
> could you build a chamber yourself using thick scrap metal?

You can look at M. A. Chatigny, S. Dunn, K. Ishimaru et a.,
"Evaluation of a class III biological safety cabinet for enclosure of
an ultracentrifuge", Applied + Environmental Micriobiology Nov 1979:
934-949. They drilled holes in a titanium rotor for a Beckman L5-50
centrifuge, then repeatedly spun it at 50,000 and powered it off until
it broke (at 53,000 RPM, which is odd since they said they were only
going up to 50,000).

The centrifuge itself was armored to contain the rotor in case of
rupture, and it did. The question was whether dangerous microbes or
viruses would be sprayed through the air and escape the BSC. Their
tests indicated that they didn't. The BSC didn't rupture when the
centrifuge jumped and smashed into the wall, but it did jump a few
inches. This looks like a 4-foot-long BSC, which would probably
weigh, I don't know, 600 lbs. OTOH I am confident the glass would
have broken if it had jumped towards the glass instead of towards the
steel wall. Anything that can knock a BSC weighing several hundred
pounds a few inches... well, do the math if you're curious, but I
doubt that a bullet could do that. Half (I think?) of the energy in a
bullet goes into the gun, and a gun is a lot less massive than a BSC.

Note that the BSC itself was not the armor that stopped the rotor; the
centrifuge armor stopped it and transferred its energy to a big heavy
thing, which is the objective.

50,000 rpm is about the lowest speed that can be called an
ultracentrifuge. The Airfuge can go up to 110,000 rpm or about
200,000g. Tabletop bucket centrifuges can do something like 25,000g
and are not considered ultracentrifuges.

A protocol calling for an ultracentrifuge might be successfully
changed to use a slower refrigerated centrifuge for a much longer time.

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