Cold Gun Aircoolant Systems Eliminate Mist & Breathing Problems In Machine Shops

Some machine tool operations require flood coolant. Not only does the liquid remove heat of friction from the tool and the work piece, it also provides lubrication that the cutting of some materials require. For other machining operations, mist coolant removes heat, provides a measure of lubricity, and minimizes (to a degree) the volume of liquid used in a flood coolant application.

This high speed photograph illustrates how flood coolant gets atomized by a machine cutting tool.

Whether you flood or mist liquid right onto a tool cutting metal, some of it’s going airborne. CNC machines are oftentimes equipped with collection systems for coolant mist, and it’s not unusual to see ambient mist collectors installed in machine shops to take care of the mist that escapes individual machines.

These mist collectors play an essential role in these facilities, as there are considerable health risks associated with exposure to these fluids, both oil- and water-based. In the U.S., the National Institutes of Health (NIH) compiles & analyzes risks associated with skin contact & inhalation of metalworking fluids. The National Institute for Occupational Safety and Health (NIOSH) has comprehensive recommendations of limitations on exposure to them. In England, the Health & Safety Executive agency likewise published a document geared toward helping machine shops and their employees work safely with them.

Speaking of NIOSH, they strategize a Hierarchy of Controls that can be applied to most any industrial process:

Elimination of the hazard isn’t always possible, but when it is, it’s the most effective option.

While mist collectors (Engineering Controls) are reasonably effective (and essential in the large number of applications where metalworking fluids are necessary), there are still a fair amount of applications where liquid coolant CAN be eliminated. For those applications, consider the EXAIR Cold Gun Aircoolant Systems.

Cold Guns not only eliminate messy and potentially hazardous liquid coolants, but also have been proven to improve cutting tool life.

Using Vortex Tube technology, EXAIR Cold Guns generate cold air flow from a supply of compressed air, instantly & on demand, with no moving parts to wear or electrical components to burn out. They’re safe, quiet, effective, and install in minutes, using a built-in bar magnet and 1/4 NPT compressed air connection.

Both Standard & High Power Systems come with Filter Separators, and are available with Single or Dual Point Hose Kits.

We know we can’t replace liquid coolant in every machining application, but if you’d like to explore elimination of it in your processes, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Get your EXAIR Catalog

I consider myself a bit Old Fashion when it comes to product catalogs! (As I sit here and look at my 3,968 page McMaster-Carr Catalog!) There’s something nice about having everything you need right in front of you. Yes I know everything is on our website also, and its a pretty slick website if I do say so myself! Check out this blog about our new and improved website! Website Blog But there is something about a paper catalog you can flip thru and see all the options!

EXAIR’s Catalog 33 is 224 pages, and covers all 16 product lines from Air Knives to Cabinet Cooler systems, to industrial vacuums. All of our cataloged products are in stock and ready to ship! Not only will you be able to find part numbers, Dimensions, Product specifications and performance. You will also find application photos to help you use the products the best way!

To get your hands on one you can either shoot a email to techelp@exair.com, or jump over to our website and provide your information and one will be shipped out! Order A Catalog Here

Jordan Shouse
Application Engineer

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Vortex Tube Cold Fraction and how it Affects Flow and Temperature Control

Vortex Tubes are the perfect solution when dealing with a variety of spot cooling applications. They use compressed air to produce a cold air stream and a hot air stream, with temperatures ranging from as low as -50°F  up to +260°F (based on ambient supply temperature) and providing as much as 10,200 Btu/hr. of cooling capacity. By simply adjusting the valve in the hot end of the Vortex Tube, you are able to control the “cold fraction” which is the percentage of air consumed by the vortex tube that is exhausted as cold air versus the amount of air exhausted as hot air. Our small, medium and large Vortex Tubes provide the same temperature drop and rise, it’s the volume of air that changes with the various sizes.

The unique physical phenomenon of the Vortex Tube principle generates cold air instantly, and for as long – or short – a time as needed.

When looking at the below performance chart, you will see that “Pressure Supply” and “Cold Fraction %” setting all play a part in changing the performance of the Vortex Tubes. Take for example, an operating pressure of 100 PSIG and cold fraction setting of 20%, you will see a 123°F drop on the cold side versus a 26°F temperature rise on the hot side. By the using the same Vortex Tube and keeping the operating pressure at 100 PSIG but changing the cold fraction to 80%, you will now see a 54°F temperature drop on the cold side and a 191° rise at the hot end.

Vortex Tube Performance Data
Vortex Tube Performance Chart

We’ve looked at how the cold fraction changes the temperature, but how does it change the flow for the various Models?

Say you are using a Model # 3240 Medium Vortex Tube which consumes 40 SCFM @ 100 PSIG. Again with the cold fraction set at 80% (80% of the consumed compressed air out of the cold end), you would flow 32 SCFM at the cold air exhaust.

40 SCFM x 0.8 (80% CF) = 32 SCFM

Using the same Model # 3240 Medium Vortex Tube but now with a 20% cold fraction (20% of consumed compressed air out of the cold end), you would flow 8 SCFM at the cold exhaust.

40 SCFM x 0.20 (20% CF) = 8 SCFM

As you can see, to achieve the colder air temperatures, the volume of cold air being exhausted is reduced as well. This is important to consider when making a Model selection. Some other considerations include the operating pressure which also has a significant effect on performance. The compressed air supply temperature is important because the above temperatures are temperature differentials, so in the example of the 80% cold fraction there is a 115F temperature drop from your inlet compressed air temperature.

If you need additional assistance, you can always contact myself or another application engineer and we would be happy to make the best selection to fit your specific need.

Jordan Shouse
Application Engineer

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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