Tag: industrial spot cooling

EXAIR’s Cold Gun Promotion

Published on by Al Wooffitt1 Comment

It’s that time of year again for EXAIR‘s Cold Gun Promotion (online only). From November 1st 2024 through to the end of the year, you can receive a Dual Point Hose Kit for free with the purchase of our promotional Cold Gun System w/ Single Point Hose Kit or promotional High Power Cold Gun System w/ Single Point Hose Kit. These hose kits come with standard point tips or 1″ fan tips. The dual point kit gives you the ability to provide cooling to more than one side of large diameter cutters and components that need cooling.

Cold Guns Systems

So, what’s so great about EXAIR’s Cold Gun? If you’re looking for a way to extend the life of your tools by keeping them cool without the mess that can be left when using a coolant, then our Cold Gun is the perfect solution. When supplied with a source of compressed air, the Cold Gun and High Power Cold Gun produces a stream of clean, cold air that is 50°F below your compressed air supply temperature. In addition to this, 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 will run maintenance free for many years!

With a magnetic base, the Cold Gun is easy to install and mount. 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 would like to discuss how an EXAIR Cold Gun can help you with your coolant application, then give us a call!

Al Wooffitt
Application Engineer

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Controlling Temperature And Flow From A Vortex Tube

Published on by Russ BowmanLeave a comment

The Vortex Tube is among the most fascinating air-operated devices to me. It’s right up there with the pneumatic impact wrench, which is my HIGHLY preferred method of removing (and replacing) a tire on a vehicle. While there are several different types of impact wrenches, they all basically use air pressure to move internal parts in a manner in which they strike (or impact) a rotating element with a socket on the end, resulting in a lot more torque being applied than if it was simply spinning a propeller attached to the shaft.

Vortex Tubes, on the other hand, all work on the same principle, discovered by a French engineer, Georges Ranque, while he was experimenting with a new design of a vacuum pump in 1922. There doesn’t seem to be any record of him completing the work on his newfangled vacuum pump, but he did continue experimenting with this device that made hot air come out one end, and cold air come out the other, getting a patent for it in 1931.

How a Vortex Tube Works: compressed air enters the vortex spin chamber (big blue arrow from above left), where the Generator imparts a spinning motion to it (red ribbon, moving to the right). When the spinning air flow reaches the other end, some of it is forced to change direction and, while still spinning, flow the other way (blue ribbon, moving to the left). The rest exits through the hot valve (represented by the yellow cone). When the spinning air flow changes directions, it gives off energy in the form of heat, causing hot air to exit one way, and cold air to exit the other.

EXAIR offers two series of Vortex Tubes:

  • 32XX series, or Maximum Refrigeration. These make the highest flows of cold air, at temperatures suitable for rapid cooling of warm objects to ambient (or below) temperatures.
  • 34XX series, or Maximum Cold Temperature. These will give you the coldest air possible – as low as minus 50°F – but at lower flows, relative to the 32XX series. I’ll go into more detail on both of these in a minute.
Sub-zero air flow from Model 3408 Vortex Tubes cools & solidifies chocolate in candy molds.

Both of these series consist of Vortex Tubes in three sizes, with multiple models in each size. The difference between the models in each series is the compressed air consumption:

You can control the temperature, and the flows (both hot and cold), of any Vortex Tube in a few different ways:

  • Supply pressure affects the total flow of the two air streams, and the magnitude of the change in temperature. Since higher pressure equals more energy, it stands to reason that, at higher pressures, the hot air will be hotter, and the cold air will be colder.
  • Cold Fraction is the percentage of the compressed air supply that gets directed to the cold end. You can get VERY cold air from a Vortex Tube by setting it to a low cold fraction. This is done by opening the Hot Valve to let more hot air out. That causes the flow rate, and the temperature of the air coming out of the cold end, to drop.
Turning the Hot Valve counterclockwise (blue arrow) lets more hot air out, which lowers the cold air flow, and temperature. Turning it clockwise (red arrow) lets less hot air out, which raises the cold air flow…and temperature.
  • Two types of Generators can be installed in an EXAIR Vortex Tube – these are what determine the series I mentioned above:
    • Type “R” (Maximum Refrigeration) Generators allow for Cold Fraction adjustments from 50-80%. With an air supply pressure of 100psig, the cold air will be 54°F (when set to an 80% Cold Fraction) to 100°F (at a 50% Cold Fraction) lower than the compressed air supply temperature. This makes them suitable for applications where rapid cooling of an object is needed.
    • Type “C” (Maximum Cold Temperature) Generators give you Cold Fraction adjustments from 20-50%. A Vortex Tube with a “C” Generator installed will give you the same 100°F temperature drop as the “R” Generator will at a 50% Cold Fraction, but at a 20% Cold Fraction, it’ll be 123°F colder than the supply. These are used where cooling to temperatures below 0°F is needed.
How to tell which Generator is installed in a Vortex Tube.

If you need to remove & replace a tire, I strongly recommend using a pneumatic impact wrench. If you need to blow cold air for something, I just as strongly recommend using an EXAIR Vortex Tube. Different applications require different series, models, and settings. Give me a call if you’d like to find out which combination of those is right for your application.

Russ Bowman, CCASS

Application Engineer
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What’s So Great About The Adjustable Spot Cooler?

Published on by Russ BowmanLeave a comment

EXAIR Adjustable Spot Coolers are ideally suited to a number of applications that need a flow of cold air on demand. Different applications will require more or less flow, and higher or lower temperatures. Let’s say you’re trying to cool an object to ambient temperature with a Model 3825 Adjustable Spot Cooler supplied with compressed air at 100psig and 70°F, but it’s not cooling the object as fast as you’d like. You can:

  • Increase the supply pressure, if possible. With a 100psig inlet pressure to the Adjustable Spot Cooler, you’re getting 20 SCFM of cold flow, at 16°F (assuming it’s set to an 80% Cold Fraction, which is usually ideal for spot cooling.) If you can get it to 120psig, you’ll increase the cold flow from 20 SCFM (80% of the 25 SCFM it’s using at 100psig) to 23.4 SCFM (80% of the 29.3 SCFM it’ll use at 120psig). And it’ll be colder (it’ll produce air with a 55°F temperature drop @120psig, vs 54°F @100psig).
EXAIR Vortex Tube Performance Chart – this is where the above – and below – ‘facts & figures’ come from.
  • Decrease Cold Fraction. Depending on the object’s size, material(s) of construction, amount of surface area available for heat transfer, etc., you could improve the cooling rate with lower temperature air, even if there’s less of it. If it’s particularly small in relation to the cold air flow pattern, a portion of that cold air flow might pass by without removing any heat at all. So, decreasing the temperature of the cold air that IS working will increase your rate of heat transfer. This is done by turning the knob of the Temperature Control Valve:
Turning the knob (2) counterclockwise opens the Temperature Control Valve, letting more of the supply flow (1) out of the hot end (3), and less of it to flow to the cold end (4). This also lowers the temperature of the cold air flow.
  • Change the Generator. The Adjustable Spot Cooler comes with a 25 SCFM Generator installed, but 15-R and 30-R Generators are included as well. Replacing the 25 SCFM Generator with a 30 SCFM Generator makes it use 30 SCFM @100psig, but you’ll increase the cold flow from 20 SCFM to 24 SCFM, assuming you leave it set at an 80% Cold Fraction. Keep in mind, though, that you can lower the Cold Fraction to get the same amount of cold flow as you were getting from the 25 SCFM Generator, but now it’ll be colder. If you open the Temperature Control Valve to a 70% Cold Fraction, you’ll reduce the cold flow to 21 SCFM of cold flow, but now it’ll be -1°F.

Everyone here at EXAIR wants you to get the most out of our products. If you’d like to find out more about how to do that, give me a call.

Russ Bowman, CCASS

Application Engineer
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Hot Air In The Aerospace Industry

Published on by Russ BowmanLeave a comment

Mankind’s adventures in aviation began with hot air, and it’s still kind of a big deal (for one particular EXAIR customer, that is) today.

How it started: In the 1780s, two French brothers, Joseph and Étienne Montgolfier, worked in their family’s paper mill. They noticed, along with everyone else, that pieces of paper were sometimes carried airborne in billows of smoke from the fires that heated the boilers. But unlike everyone else, they became curious as to why this happened…and how they might exploit this strange phenomenon to send something more substantial than some paper scraps through the air.

After a good deal of experimentation and trips “back to the drawing board” (they thought it was the smoke, not the heat, that caused the rise for a while), they began making public demonstrations of their first successful hot-air balloons in the summer of 1783. By autumn, having flown a sheep, a duck, and a rooster in a tethered balloon (to an altitude of about 1,500 feet on a flight that lasted about 8 minutes), they constructed a balloon large enough for two humans which flew successfully for almost half an hour, to a height of 3,000 feet. Early enthusiasts who came out to witness some of these flights included King Louis XVI, Queen Marie Antoinette, and American statesman (and quite the inventor himself) Benjamin Franklin.

The Montgolfier brothers decorated their balloons with the fleur-de-lis, zodiac symbols, and portraits of the King. I think it says a lot about ballooning that nowadays we have Sylvester the Cat, Tweety Bird, and even Spider-Pig.

How it’s going: I’m not going to lie; your level of fascination with the rest of this blog will depend on how fascinating you find the phenomenon of the Vortex Tube…which was, in fact, discovered by another French inventor, Georges Ranque:

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

Most Vortex Tube applications involve the use of the cold air flow, but a number of customers do indeed use the hot air flow. A material supplier to the aircraft & aerospace industry makes a flexible, porous strand of material that, after fabrication, passes through a wash tank prior to cutting to size. They wanted to speed up the drying time, but it was impractical to use electrically powered hot air blowers or heat guns. By using an EXAIR Model 3275 Large Vortex Tube set to a 70% Cold Fraction, they’re able to blow a little over 22 SCFM of 220°F air onto the strand, which effectively dries it to their specification, quickly & safely.

The EXAIR Vortex Tube. Cold air from one end; hot air from the other. Fully adjustable. You can use either…it’s fine with us; whatever you need.

Other EXAIR products that have been notably popular in the aerospace industry are engineered Air Nozzles, Static Eliminators, Air Amplifiers, and some even use Vortex Tubes & Spot Cooling Products for their COLD air flow. If you’d like to find out more about getting the most out of your compressed air system like the folks in the aerospace industry do, give me a call.

Russ Bowman, CCASS

Application Engineer
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