On Thu, 27 Oct 2005 08:55:28 -0400, "gfulton"
wrote:


"Tom Miller" wrote in message
...


What on earth do you want a centrifuge for w.r.t. homebrewing?
I've done it for years without ever seeing the need, and we have two
boutique breweries around, one in the valley and one in the village and
neither of them ever owned a centrifuge (nor do the large commercial
German breweries I've visited)?!?

We had two, 100 Hp centrifuges at a brewery that I worked at In Sydney. We
used them to spin out most of the yeast before the beer was filtered. It
save a significant amount of money in diatomaceous earth filter powder as
well as saving on the disposal costs of used filter medium..
They frightened hell out of me. The rotor weighed about 100 Kg and spun at
300 rpm. . They used an eddy current drive to get it up to speed. It took
over an hour to get to operating speed from cold start.

I did a "back of an envelope' calculation with regard to the stored energy
in one of these things,and avoided them like the plague ever since.

Tom Miller



Is this RPM right? 220 lbs. at 300 RPM just doesn't seem all that dangerous
to me. How much weight was spinning when it was loaded?


It depends on the size of the 'fuge. With a 10 ft dia 'fuge,
tangential velocity at 300 RPM is 157 ft/sec or about 107 mph with
about 150 G's on the load -- so the 220 lb mass is straining to leave
the bucket with 33,000 lb of force if I did me sums right.

I once saw a $20K (1966 dollars) electrostatically-suspended gyro fly
thru the 'fuge housing, go about 30 feet and then thru a brick wall.
There were no pieces larger than a nickel left. I think that one only
went up to 100 G's.