"anorton" wrote in message
m...

"Bob La Londe" wrote in message
...
Ok... I'm still mulling over the possibility of a Hilsch tube on one of
my machines as the coolant and to blow chips away from the cutter. I see
many commercial ones are made out of stainless, but that just isn't in my
plans if I make one. Stainless is beyond my easy working level.

I have some large aluminum bar stock laying around, (left over from
another project) and I was thinking I could turn one out of it. My
quandry is in this. I only ran across a few mentions of heat sinking in
regards to Hilsch tubes. One article said to heat sink the whole thing.
I think they just meant the whole heat separator/exchangers side of it.
It would be counter intuitive to heat sink the cold air outlet tube. I
would think you would want to insulate that. The thing is the physics of
it is beyond me. I get the basics of both principle said to be at work.
It's the details.

I could easily turn heat sink fins on the outside. I just wonder if that
will provide a lower ouput temperature, or if somehow it might reduce the
efficiency of the design somehow?


I think one goal is to keep heat from migrating through the tube from the
hot end to the cool end. The best way to do this would be to make it from
a material with low thermal conductivity, which may be why they use
stainless.

I was mulling that fine distinction over in my head as well. I think I
might have a piece of acetal plastic I could machine as a thread in cold air
tube and diaphragm for the cold end.


The hot air is near the outside over most of the length of the tube with
the cool air in the center, so that is why heatsinking the whole
cylindrical part of the tube might make sense. However, I agree
heatsinking the cold outlet itself does not make much sense.

Most refrigerators work more efficiently if the hot side is kept from
getting too hot. I do not know enough about the theory of these tubes to
say for sure if that is the case here, but it would certainly make sense.

I once bought one of these for an esoteric cooling problem. It was so
noisy we decided not to use it.