In use, aren't these guns quite loud? - GWE

David Utidjian wrote:
Hari Seldon wrote:

Have any of you used the various cold air gun coolant
systems and if you have, what are your opinions on the
products?

http://www.exair.com/spotcooling_products/cg_page.htm
http://www.airtxinternational.com/ca...FUgxIgodaXyN-A

http://www.pelmareng.com/Spot_Cooling_Systems.html
http://www.4-airknives.com/cooltool.htm


Those are all baased on the Hilsch Vortex Tube idea which is a really
cool device (no pun intended). The technology has been around since
before WWII (see http://en.wikipedia.org/wiki/Vortex_tube ).

Depending on whether you have the time for such a project... a simple
one that "works" can be built in minutes out of scrap bin and bits of
threaded pipe. I certainly wouldn't pay $200 for one.

I built my first one based on an article from an old copy of Scientific
American. A copy is he http://www.visi.com/~darus/hilsch/

Lots of good info on the web about these devices. There are no
particular patents on the basic device... its original patent has long
since expired. There might be some on significant improvements to the
device but I am not aware of them.

As far as boosting the cooling effect is concerned you would be MUCH
better off if you pre-cool the incoming air to the device rather than
trying to cool the outgoing air. All of mine cool the incoming,
nominally room temperature, air to _below_ freezing already. In fact to
pass the output through an "ice bath" or whatever may actually heat it up!

In essence the way it works is that it separates the cool molecules from
the warm molecules... send the cool ones out one end and the warm out
the other.

Unless you have plenty of compressed air on hand the device is not very
efficient as far as cooling effect/KWh.

For much more info see the links at the bottom of the Wikipedia page.
Especially check out: http://www.cockerill.net/rhvtmatl/

-DU-...etc...