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

Send me an Email
Find us on the Web 
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Twitter: @EXAIR_JS

EXAIR Cold Gun Overview

In any machining operation, tool wear is an inevitability. Cutting tools heat up due to friction and this heat contributes to premature tool wear. As tooling wears, poor tolerances and dimensional inaccuracy are common. Additionally, as the cutting edge dulls increased cutting force is required which further increases the amount of heat generated.

Coolants can be used to reduce friction and help mitigate some of the wear, but then you’re left with the mess that coolant brings along with it both on the part and in the machine itself. What if I were to tell you that there’s a way to mimic the effects of coolant, but without all of the mess? All of this can be achieved with just a supply of compressed air and one of EXAIR’s Cold Gun Systems.

EXAIR’s Cold Gun was a Product of the Year finalist in 2007. By using only a source of compressed air, the Cold Gun and High Power Cold Gun produces a stream of clean, cold air 50° (28°C) below your compressed air supply temperature. The Cold Gun is very quiet at only 70dBA and has no moving parts to wear out. Just supply it with clean, dry compressed air and it’s maintenance free!

Cold Guns Systems

The Cold Gun is pre-set to an 80% Cold Fraction. In other words, 80% of the compressed air supplied to it will exhaust from the cold end of the tube, 20% from the hot end. This prevents the Cold Gun from freezing up during use and optimizes the gun’s cooling capacity. The Cold Gun is an ideal alternative to messy and expensive coolant mist systems. It eliminates the cost of purchase and disposal of cutting fluids as well as worker related health problems from breathing airborne coolant or slipping on wet floors. Replacing a coolant-based system also eliminates the need for secondary cleaning operations after milling or drilling.

The Cold Gun is an invaluable tool for machining a wide range of plastics and other materials that may become contaminated when using traditional coolants or oils. The clean, cold air from the outlet of the Cold Gun keeps the part cool, clean, and dry. Take for example this application where an OEM for the plastics industry uses EXAIR Cold Guns in place of a coolant system.

If you have an application that you believe would be better served by the use of an EXAIR Cold Gun, give us a call. Get one on order today and take advantage of our limited time promotion and receive a FREE Dual Point Hose Kit upgrade!

Tyler Daniel, Application Engineer

E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD
Ph. 1-800-903-9247 or 1-513-671-3322

Cold Gun Replaces Inefficient and Ineffective Open Pipe

In any machining operation, tool wear is an inevitability. Cutting tools heat up due to friction and this heat contributes to premature tool wear. As tooling wears, poor tolerances and dimensional inaccuracy are common. Additionally, as the cutting edge dulls increased cutting force is required which further increases the amount of heat generated and exacerbates the problem.

Coolants can be used to reduce friction and help mitigate some of the wear, but then you’re left with the mess that coolant brings along with it both on the part and in the machine itself. What if I were to tell you that there’s a way to mimic the effects of coolant, but without all of the mess? All of this can be achieved with a supply of compressed air and one of EXAIR’s Cold Gun Systems.

HP_coldgun_2007finalist

I recently worked with a metalworking company on replacing several open-pipe blowoffs on their CNC machines with EXAIR Cold Guns. The open pipes were not effective at keeping the tooling cool, but did a decent job of blowing away chips. Premature tool wear was leading to increased downtime and slowing production as they were frequently having to replace the tooling. Not to mention, these blowoffs were extremely loud and forced anyone on the shop floor to be wearing in-ear and over-the-ear hearing protection.

Each of their CNC machines had one open-line coolant hose or similarly sized open tube blowing compressed air onto the tool. Temperatures in the facility get fairly warm in the summer and this was having little to no impact. They didn’t want to deal with the mess that comes along with coolant, so they looked to EXAIR for a solution. They ended up installing (1) 5215 Single Point Cold Gun System for trial on one of their machines.

Immediately they noticed the reduction in sound as the Cold Gun operates at just 70 dBA, but they also noticed a 20% reduction in tool wear compared to the open-air lines after a short time in operation. It didn’t entirely eliminate the need for hearing protection as there are other processes occurring, but it did lower it to a point that they weren’t forced to use both in-ear and over-the-ear protection.

EXAIR’s Cold Gun was a Product of the Year finalist in 2007. Using only a source of compressed air, the Cold Gun and High Power Cold Gun produces a stream of clean, cold air 50° (28°C) below your compressed air supply temperature. The Cold Gun is very quiet at only 70dBA and has no moving parts to wear out. Just supply it with clean, dry compressed air and its maintenance free!

The Cold Gun has been preset to achieve maximum refrigeration. This prevents the Cold Gun from freezing up during use and optimizes the gun’s cooling capacity. The Cold Gun is an ideal alternative to messy and expensive coolant mist systems. It eliminates the cost of purchase and disposal of cutting fluids as well as worker related health problems from breathing airborne coolant or slipping on wet floors. Replacing a coolant-based system also eliminates the need for secondary cleaning operations after milling or drilling.

If you have an application that you believe would be better served by the use of an EXAIR Cold Gun, give us a call.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

 

Cold Guns for Spot Cooling or Replacing Mist Systems

By using only a source of compressed air, the Cold Gun and High Power Cold Gun produces a stream of clean, cold air 50°F (28°C) below your compressed air supply temperature. The Cold Gun is very quiet at only 70 dBA and has no moving parts to wear out. Just supply it with clean compressed air and it’s maintenance free.

How does it work, and what are the benefits?

  • The Cold Gun uses compressed air to produce a stream of clean, cold air at 50°F (28°C) below supply air temperature. Generally this will be 20°F-30°F outlet temperature.
  • They use Vortex Tube technology…no moving parts to wear out.

How A Vortex Tube WorksInstant cold air flow with no moving parts!

  • Cold flow and temperature are preset to optimize cooling capability, and are non-adjustable to prevent freeze-up during use.
  • Eliminates the expense of both the purchase & disposal of cutting fluids when replacing expensive mist systems.
  • Removes the potential for health problems associated with breathing mist & vapors, and the safety issue of slipping on a wet floor.

Cold Gun Aircoolant System selection is easy & straightforward…we offer a standard, and a High Power version to meet your specific needs.

CG
Four systems to choose from, to meet most any need.

We also offer Single & Dual Point Hose Kits, to further meet the needs of your application.

One of the best applications I have seen with our cold gun came from a customer in Peru. They are a gold mining operation and they were having trouble with the liquid they were using to cool a saw. Read all about it here!

IMG_20180613_094120_HDR

If you have an application that you believe would be better served by the use of an EXAIR Cold Gun, give us a call.

Jordan Shouse
Application Engineer
Send me an email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS