Video Blog: Cold Gun Maintenance Video

Is your Cold Gun still working like when it was new? If not, check out this video – you can very likely restore it to “as new” performance with a simple disassembly & cleaning.

If you have any questions about maintenance on your Cold Gun, or any of our products, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
Visit us on the Web
Follow me on Twitter
Like us on Facebook

EXAIR Mini Cooler™: Overview 

EXAIR Mini Coolers

EXAIR offers a line of spot cooling devices to blow cold air to remove heat.  Heat can cause premature failures and shortened tool life.  We use the Vortex Tube phenomenon to make very cold air without any moving parts or Freon.  They only need compressed air as the “engine” to spin the air streams into two parts; hot air and cold air.  They are maintenance free and can supply cold air down to a temperature of -50oF (-46oC).  EXAIR “dresses up” a Vortex Tube to make a more functional device for spot cooling.  In this blog, I will cover the smallest of our spot coolers; the Mini Cooler™.   

The EXAIR Mini Cooler was designed for tight areas to cool small objects.  It has a cooling capacity of 550 BTU/hr (139Kcal/hr).  It only uses 8 SCFM (227 SLPM) at 100 PSIG (6.9 bar).  The system will come with a manual drain Filter Separator with mounting bracket, a Swivel Magnetic Base with 100 lb. (45.5Kg) pull magnet, and a flexible hose kit.  We offer two options for the flexible hose kit; a Single Point Hose Kit, model 3808, and a Dual Point Hose Kit, model 3308.  The Single Point Hose Kit will give you one flexible outlet to easily position the cold air stream near the target point.  It will also include a round point tip and a flat-fan tip.  The Dual Point Hose Kit adds a split to have two separate cold outlets; still including the round and flat-fan tips.  With these features, the Mini Cooler is easy to mount, use, and move for optimal cooling and blowing. 

Model 3308

When using the Mini Cooler, the flexible cold outlets can easily bend around fixtures, spindles, and welding horns.  The swivel magnetic base gives extra adjustment at the base of the cooler to aid in “hard to reach” places.   To further the benefits of the cooler, the operating pressure can be changed to lower or raise the cooling capacity to meet your demands.  At 100 PSIG (6.9 bar), the cold air flow can reach a temperature as low as 20oF (-7oC).

Some applications for the Mini Cooler would include small diameter milling and drilling where the cold air can keep the tool cool and remove the chips.  It can also be used for soldering, industrial sewing, ultrasonic welding, or even small punching applications to list a few.  With the dual point hose kit, it is ideal for targeting two sides of a cutter, aiming at multiple blades where material is being slit, or cooling multiple ultrasonic points for faster cycle times.

If you believe that you have an application where spot cooling could increase production rates and/or extend tool life, you can contact an Application Engineer at EXAIR.  We can offer the Mini Cooler for smaller targets; or, larger versions like the Adjustable Spot Cooler and Cold Gun Aircoolant System™.  We are looking forward to hearing from you.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Vortex Tube Cold Fractions Explained

Simply put, a Vortex Tube’s Cold Fraction is the percentage of its supply air that gets directed to the cold end. The rest of the supply air goes out the hot end. Here’s how it works:

The Control Valve is operated by a flat head screwdriver.

No matter what the Cold Fraction is set to, the air coming out the cold end will be lower in temperature, and the air exiting the hot end will be higher in temperature, than the compressed air supply.  The Cold Fraction is set by the position of the Control Valve.    Opening the Control Valve (turning counterclockwise, see blue arrow on photo to right) lowers the Cold Fraction, resulting in lower flow – and a large temperature drop – in the cold air discharge.  Closing the Control Valve (turning clockwise, see red arrow) increases the cold air flow, but results in a smaller temperature drop.  This adjustability is key to the Vortex Tube’s versatility.  Some applications call for higher flows; others call for very low temperatures…more on that in a minute, though.

The Cold Fraction can be set as low as 20% – meaning a small amount (20% to be exact) of the supply air is directed to the cold end, with a large temperature drop.  Conversely, you can set it as high as 80% – meaning most of the supply air goes to the cold end, but the temperature drop isn’t as high.  Our 3400 Series Vortex Tubes are for 20-50% Cold Fractions, and the 3200 Series are for 50-80% Cold Fractions.  Both extremes, and all points in between, are used, depending on the nature of the applications.  Here are some examples:

EXAIR 3400 Series Vortex Tubes, for air as low as -50°F.

A candy maker needed to cool chocolate that had been poured into small molds to make bite-sized, fun-shaped, confections.  Keeping the air flow low was critical…they wanted a nice, smooth surface, not rippled by a blast of air.  A pair of Model 3408 Small Vortex Tubes set to a 40% Cold Fraction produce a 3.2 SCFM cold flow (feels a lot like when you blow on a spoonful of hot soup to cool it down) that’s 110°F colder than the compressed air supply…or about -30°F.  It doesn’t disturb the surface, but cools & sets it in a hurry.  They could turn the Cold Fraction down all the way to 20%, for a cold flow of only 1.6 SCFM (just a whisper, really,) but with a 123°F temperature drop.

Welding and brazing are examples of applications where higher flows are advantageous.  The lower temperature drop doesn’t make all that much difference…turns out, when you’re blowing air onto metal that’s been recently melted, it doesn’t seem to matter much if the air is 20°F or -20°F, as long as there’s a LOT of it.  Our Medium Vortex Tubes are especially popular for this.  An ultrasonic weld that seals the end of a toothpaste tube, for example, is done with a Model 3215 set to an 80% Cold Fraction (12 SCFM of cold flow with a 54°F drop,) while brazing copper pipe fittings needs the higher flow of a Model 3230: the same 80% cold fraction makes 24 SCFM cold flow, with the same 54°F temperature drop.

Regardless of which model you choose, the temperature drop of the cold air flow is determined by only two factors: Cold Fraction setting, and compressed air supply pressure.  If you were wondering where I got all the figures above, they’re all from the Specification & Performance charts published in our catalog:

3200 Series are for max cooling (50-80% Cold Fractions;) 3400’s are for max cold temperature (20-50% Cold Fractions.)

Chocolate cooling in brown; welding/brazing in blue.

EXAIR Vortex Tubes & Spot Cooling Products are a quick & easy way to supply a reliable, controllable flow of cold air, on demand.  If you’d like to find out more, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
Visit us on the Web
Follow me on Twitter
Like us on Facebook

Adjustable Spot Cooler: How Cold Can You Go?

I had the pleasure of discussing a spot cooling application with a customer this morning. He wanted to get more flow from his Adjustable Spot Cooler, but still keep the temperature very low.  He machines small plastic parts, and he’s got enough cold flow to properly cool the tooling (preventing melting of the plastic & shape deformation) but he wasn’t getting every last little chip or piece of debris off the part or the tool.

After determining that he had sufficient compressed air capacity, we found that he was using the 15 SCFM Generator. The Adjustable Spot Cooler comes with three Generators…any of the three will produce cold air at a specific temperature drop; this is determined only by the supply pressure (the higher your pressure, the colder your air) and the Cold Fraction (the percentage of the air supply that’s directed to the cold end…the lower the Cold Fraction, the colder the air.)

Anyway, the 15 SCFM Generator is the lowest capacity of the three, producing 1,000 Btu/hr of cooling. The other two are rated for 25 and 30 SCFM (1,700 and 2,000 Btu/hr, respectively.)

He decided to try and replace the 15 SCFM Generator with the 30 SCFM one…his thought was “go big or go home” – and found that he could get twice the flow, with the same temperature drop, as long as he maintained 100psig compressed air pressure at the inlet port.  This was more than enough to blow the part & tool clean, while keeping the cutting tool cool, and preventing the plastic part from melting.

Model 3925 Adjustable Spot Cooler System comes with a Dual Outlet Hose Kit, and three Generators for a wide range of cooling performance.

If you’d like to find out how to get the most from a Vortex Tube Spot Cooling Product, give me a call.

Russ Bowman
Application Engineer
Find us on the Web
Follow me on Twitter
Like us on Facebook