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

On 13 Mar 2006 16:37:27 -0800, 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




I've used the Exair brand. Works great on plastics.

Put hot water pipe insulation wrap on the outlet nozzle and run the intake
air line into a bucket of ice water. Use a long length (10-20 feet) of air
line coiled up in the bucket. That will really help drop the temp of the
output air.
--
Skuke
Reverse the domain name to send email

skuke writes:

Put hot water pipe insulation wrap on the outlet nozzle and run the
intake air line into a bucket of ice water. Use a long length (10-20
feet) of air line coiled up in the bucket. That will really help drop
the temp of the output air.

Drained ice is more efficient than floating ice at flash cooling. Try
putting a hole in the bucket so you don't have liquid water in it. It is
insulating the hose from phase change of the ice and thus the flash cooling
efficiency (like a wet suit keeps you warm). And put a refrigerated air
drier ahead, so you're not wasting time removing latent heat and sputtering
liquid condensate.

On Mon, 13 Mar 2006 22:05:09 -0600, Richard J Kinch wrote:

skuke writes:

Put hot water pipe insulation wrap on the outlet nozzle and run the
intake air line into a bucket of ice water. Use a long length (10-20
feet) of air line coiled up in the bucket. That will really help drop
the temp of the output air.

Drained ice is more efficient than floating ice at flash cooling. Try
putting a hole in the bucket so you don't have liquid water in it. It is
insulating the hose from phase change of the ice and thus the flash cooling
efficiency (like a wet suit keeps you warm). And put a refrigerated air
drier ahead, so you're not wasting time removing latent heat and sputtering
liquid condensate.



We had a drier so condensation was not a problem.

I am confused though why you say drained iced would be more efficient than a
water bath of ice water.

Water is a much better conductor of heat than air, so wouldn't more heat
tranfer from the hose into the bucket of ice water rather than a bucket of
ice air? I know that if I stuck my hand into ice water, it would be much
colder than sticking into a bucket with ice cubes.

Please un-confuse me.
--
Skuke
Reverse the domain name to send email

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

It depends on what you're going to use it for. I see a fellow said it works
great for plastics. Sounds right. I tried one for grinding endmills, almost
useless. There's just too much heat being generated compared to the ability
of the gun to carry it away. On occasion I use an air blast for cooling and
chip evacuation when milling deep pockets. Again, a cold air gun wouldn't
help much here.

Karl

skuke writes:

Water is a much better conductor of heat than air, so wouldn't more
heat tranfer from the hose into the bucket of ice water rather than a
bucket of ice air?

You have to appreciate thermodynamics. Conduction is not the issue.
The phase change of the ice is the heat sink, not the liquid water. The
ice should be in direct contact against the hose, pressing against it by
force of gravity. Melted ice has spent its cooling ability, so you must
drain it away. Unlike ice, liquid water temperature rises as it gains
heat, and the efficiency drops.

An example is how a cold plate works for flash cooling beverages in a
soda fountain. Drained ice is piled on top. Look at just about any
restaurant, like Wendy's where the fountain is right at the sales
counter.

I know that if I stuck my hand into ice water, it would be much
colder than sticking into a bucket with ice cubes.

No, you're confusing temperature and heat, two different things. Liquid
water has no heat sinking capacity compared to ice. If you put your
hand into a pound of chilled water, the result will be a much higher
temperature than if you put your hand into a pound of slush.

Karl Townsend 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?

On occasion I use an air blast for cooling and chip evacuation
when milling deep pockets. Again, a cold air gun wouldn't help
much here.

Seems like this is where a cold air gun would really come in handy.

According to one of the web sites above, if the incoming air is at
75* the cold air gun will drop this to 0* and you have the benefit
of the chips being blown out of the pocket/slot, in addition to not
having to deal with the mess from liquid coolant.

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...

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...

Grant Erwin wrote:
In use, aren't these guns quite loud? - GWE

Yes, they can be. The device can make a full range of audible sounds
(and does) it just depends on which one(s) are dominant. On most of the
commercial units have some sort of muffler on one of both ends. The
higher frequencies are a particular problem.
One of my units was made by MAC tools for testing chokes and thermal
switches on cars. It has a foam lined "cold side" and a wire mesh in the
"hot side". To my ears it puts out a very dull roar. It was made about
20 years ago.

In some of the literature they mention attempts to use the devices for
cooling/heating where compressed air would be plentiful (in jet
aircraft?)... I seem to remember they tried using lead plates to damp
out some of the higher frequency harmonics. If the particular noise the
device makes is irritating enough it wouldn't be very useful in such an
environment.

Another use where noise may be a problem is in environmental suits for
sand blasters. Since compressed air is plentiful it can be used to cool
and ventilate the hood (or the whole suit). I have never used such a
suit so I don't know how they deal with the noise levels.

-DU-...etc...