A manufacturer of automotive power transmission shafts was experiencing frequent failure of high pressure plastic rollers on their spin tester. There are four rollers in a 90° array that center the shaft during spin testing. They exert a pressure of around 1,500psi onto the shaft while it’s rotating at 1,000rpm. This generates enough heat to actually melt the rubber coating on rollers, which means stopping testing (which holds up production) while they change out the rollers. Just for it to start all over again.
Thing was, they wanted to mount the Adjustable Spot Coolers where they could have access to the Temperature Control Valve, but the cold air Hose Kit wouldn’t reach the shaft. So they got a couple of extra sections of the cold air hose…they needed one section of the ‘main’ (shown circled in blue, below) to reach into the test rig’s shroud, and two sections of the ‘branch’ (circled in green) to reach to each roller.
Now, adding too much hose length will start to put line loss on the cold air flow, and it will pick up heat from the environment. But if you just need that extra foot of hose to get the job done, this generally works just fine. The extra foot or so they’ve added (5″ to the main and 6″ to each branch) has solved their problem…they haven’t had to replace a roller since the Adjustable Spot Cooler Systems were installed.
The EXAIR Vortex Tubes use compressed air to generate cold air down to -50 deg. F (-46 deg. C) without any moving parts, freon, or electricity. By design, it will produce hot air at one end and cold air at the other. EXAIR offers different cooling capacities ranging from 135 BTU/hr (34 Kcal/hr) to 10,200 BTU/hr (2,570 Kcal/hr). This cooling phenomenon begins by spinning the air at a high rate of speed inside the Vortex Tube. The “separation” of temperatures starts at the generator. In this blog, I will discuss the features of the generator and how our design allows for an efficient way to cool and heat the air flows.
EXAIR stocks three different sizes of the Vortex Tubes; small, medium, and large. Each Vortex Tube will use a generator to define the cooling capacity and compressed air usage. When compressed air enters the Vortex Tube, it will have to pass through the generator first. The generators are engineered with vane openings to initiate the spinning of the air and to control the amount of air that can pass through it. As an example, for a medium-sized Vortex Tube, a model 10-R generator will only allow 10 SCFM (283 SLPM) of air at 100 PSIG (6.9 Bar). While in that same size body, a model 40-R generator will allow 40 SCFM (1,133 SLPM) of air at 100 PSIG (6.9 Bar) to be used. Precision in the design of the generators is what sets EXAIR apart with efficiency and effectiveness in cooling.
EXAIR created a chart to show the temperature drop for the cold end and temperature rise for the hot end, relative to the incoming compressed air temperature. Across the top of the chart, we have Cold Fraction and along the side, we have the inlet air pressure. The Cold Fraction is the percentage of the inlet air that will blow out the cold end of the Vortex Tube. This is adjustable with a Hot Exhaust Air Valve at the hot end.
As you can see from the chart, the temperature difference changes as the Cold Fraction and inlet air pressure changes. You may notice that it is independent of the size of the generator. So, no matter which size Vortex Tube or generator is used, the temperature drop and rise will follow the chart above. But just remember, cooling capacity is different than cooling temperature. At the same settings, a larger generator will give you more mass of air to cool faster.
Now, let’s look inside the Vortex Tube (reference photo above). As the compressed air passes through the generator, the change in pressure will create a powerful vortex. This spinning vortex will travel toward one end of the tube where there is an air control valve, or Hot Air Exhaust Valve. This valve can be adjusted to increase or decrease the amount of hot air that leaves the Vortex Tube. The remaining part of the air is redirected toward the opposite end as the cold flow, or Cold Fraction.
Now, what separates EXAIR Vortex Tubes from our competitors are the three different styles of generators and two different materials for each size. These generators are engineered to optimize the compressed air usage across the entire Cold Fraction chart above. With temperatures above 125 oF (52 oC), EXAIR offers a brass generator for the Vortex Tubes. The same precision design is applied but for higher ambient temperatures. With the wide range of Vortex Tubes and generators, we can tackle many types of cooling applications.
If you would like to discuss your cooling requirement with an Application Engineer at EXAIR, we will be happy to help. This unique phenomenon to generate cold air with no moving, freon, or electricity could be a great product to use in your application.
Throughout my tenure with EXAIR there are may days where I have tested different operating pressure, volumetric flow rates, back pressures, lengths of discharge tubing, generator compression, and even some new inquiries with cold air distribution all on a vortex tube. These all spawn from great conversations with existing customers or potential customers on different ways to apply and applications for vortex tubes.
Many of the conversations start in the same spot… How exactly does this vortex tube work, and how do I get the most out of it? Well, the answer is never the same as every application has some variation. I like to start with a good idea of the area, temperatures, and features of exactly what we are trying to cool down. The next step is learning how fast this needs to be done. That all helps determine whether we are going to be looking at a small, medium, or large vortex tube and which cooling capacity to choose. After determining these factors the explanation on how to adjust the vortex tube to meet the needs of the application begins.
This video below is a great example of how a vortex tube is adjusted and what the effects of the cold fraction have and just how easy it is to adjust. This adjustment combined with varying the air pressure gives great versatility within a single vortex tube.
The table below showcases the test points that we have cataloged for performance values. As the video illustrates, by adjusting the cold fraction lower, meaning less volumetric flow of air is coming out of the cold side and more is exhausting out the hot side, the colder the temperature gets.
This chart helps to determine the best case scenario of performance for the vortex tube. Then the discussion leads to delivery of the cold or hot air onto the target. That is where the material covered in these two blogs, Blog 1, Blog 2 comes into play and we get to start using some math. (Yes I realize the blogs are from 2016, the good news is the math hasn’t changed and Thermodynamics hasn’t either.) This then leads to a final decision on which model of vortex tube will best suit the application or maybe if a different products such as a Super Air Amplifier (See Tyler Daniel’s Air Amplifier Cooling Video here.)is all that is needed.
Where this all boils down to is, if you have any questions on how to apply a vortex tube or other spot cooling product, please contact us. When we get to discuss applications that get extremely detailed it makes us appreciate all the testing and experience we have gained over the years. Also, it helps to build on those experiences because no two applications are exactly the same.
The EXAIR Mini Cooler family is one of the many vortex tube based Spot Cooler products that EXAIR offers. This is the smallest of the group coming in at 550 BTU/hr of cooling capacity. The Mini Cooler Systems are available in two options.
The Single Point Outlet option will give you ten inches of flexible cold outlet to easily position the cold air stream near the target point.
The Dual Point Outlet option gives ten inches of 1/4″ flexible outlet that then splits to two separate four inch lengths of 1/4″ flexible cold outlet hoses.
Both include point or flat fan tips for the cold air outlets
Both include a manual drain filter separator
both include the swivel magnetic base with 100 lb. pull magnet.
The single point hose kit is ideal for small diameter milling or drilling applications where the cold air can cover the contact area of the cutter. It can also be used on soldering, industrial sewing, ultrasonic welding, or even small punching applications to list just a few.
The dual point hose kit is ideal for two separate small diameter cutters, one larger diameter cutter, rotary style knives where there material is being slit, or larger diameter multi-point ultrasonic welders/punches.
When using the Mini Cooler the adjustable cold outlet stays in place and can easily bend around fixtures, spindles, welding horns, or dye aligning pins. The swivel magnetic base gives additional adjustment at the base of the cooler to aid in the versatility of this product. To further the adjustability of the cooler the operating pressure can easily be adjusted to lower or raise the cooling capacity of the Mini Cooler to meet the demands of the precise application.
If you believe you have an application that would benefit from the use of a Mini Cooler, or you are unsure which product would be ideal for your application please contact an Application Engineer. we are all here, willing to help however possible to get your application improved in both safety and efficiency.
By using only a source of compressed air, theCold 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 Tubetechnology…no moving parts to wear out.
Instant 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 Powerversion to meet your specific needs.
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!
If you have an application that you believe would be better served by the use of an EXAIR Cold Gun, give us a call.
The Adjustable Spot Cooler is a low cost, reliable , maintenance free way to provide spot cooling to a myriad of industrial applications. Simply turn the knob, and the temperature can be changed to suit the needs of the process. The Adjustable Spot Cooler delivers precise temperature settings from -30°F (-34°C) to room temperature.
It can produce temperatures form -30°F to +70°F (-34°C tp +21°C)
Parts included for flow rates of 15, 25 and 30 SCFM (425, 708, 850 SLPM.) The unit comes from the factory set at 25 SCFM (708 SLPM)
It can produce refrigeration up to 2,000 BTU/hr (504 Kcal/hr.)
A swivel magnetic base allows for easy mounting and portability, you can move it from machine to machine as needed. The flexible cold air outlet tubing holds its position and is easy to aim. Most importantly, there are no moving parts or CFC’s, ensuring maintenance free operation.
The Adjustable Spot Cooler incorporates a vortex tube to convert a supply of compressed air (1) into two low pressure streams, one hot and one cold. With the turn of a knob, the temperature control valve (2) allows some hot air to flow through a muffling sleeve and out the hot air exhaust (3). The opposite end provides a cold air stream (4) that is muffled and discharged through the flexible hose, which directs it to the point of use. The swivel magnetic base (5) provides easy mounting and portability.
The Adjustable Spot Cooler can produce a wide range of air flows and temperatures as determined by the temperature control valve knob setting and the generator installed. The generator controls the total SCFM (SLPM) of compressed air consumption, and is easy to change. From the factory, the 25 SCFM (708 SLPM) generator is installed, producing up to 1,700 BTU/hr (429 Kcal/hr) of cooling. For less cooling, the 15 SCFM (425 SLPM) generator can be installed, providing up to 1,000 BTU/hr (252 Kcal/hr) of cooling. And for more cooling, the 30 SCFM (850 SLPM) generator can be installed, providing up to 2,000 BTU/hr (504 Kcal/hr) of cooling.
Two (2) Systems are available as shown below, and include the 15 and 30 SCFM (425 and 850 SLPM) generators, a filter separator, and either a single or dual point hose kit.
Adjustable Spot Cooler Systems
If you have questions about the Adjustable Spot Cooler or any of the 16 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.
Among EXAIR’s comprehensive line of Intelligent Compressed Air Products, the Vortex Tube stands out as a unique, and fascinating, solution for a variety of applications requiring a flow of cold air:
Cabinet Cooler Systems: clean, cold air to protect electrical and electronic components housed in an enclosure. Installs in minutes; no moving parts; reliable & maintenance free.
Cold Gun Aircoolant Systems: Direct, focused flow of cold air to replace messy coolant in machining, cutting, drilling, grinding, etc., applications. Integral magnet base for quick & easy installation; single or dual outlet hose kits; standard or High Power to meet any need. Optimized flow for maximum cooling and freeze prevention.
Adjustable Spot Cooler: Similar to the Cold Guns in many ways, but with variable performance for specific applications. Cold air to -30°F (-34°C) on demand.
Mini Cooler: Similar to the Cold Guns and Adjustable Spot Coolers – magnetic base mounting and single or dual outlet hose kits, but more compact. Lower flows for smaller jobs.
Then there are the Vortex Tubes themselves…at the heart of all of these products, but perfectly capable all on their own. In fact, in certain situations, “plain old” Vortex Tubes have been used to do the exact same jobs as all of the above products. They can even be customized, in and of themselves, to meet specific installation, operation, and/or performance needs:
High Temperatures: It should come as no surprise that cold air is often needed because a heat-sensitive item is located in a high heat environment.
Vortex Tubes come standard with plastic Generators and Buna o-rings, which are good for ambient temperatures up to 125°F (52°C).
High Temperature Vortex Tubes are fitted with brass Generators and Viton o-rings for environments where the temperature can reach 200°F (93°C).
Preset temperature & flow: Many times, the ability to adjust the performance of a Vortex Tube is a big benefit, but occasionally it’s a liability.
I know none of your co-workers are like this (nor are mine) but I’ve heard of people who think they “know better” and are prone to tampering with something that is (or WAS) working just fine, thank you very much.
Perhaps you actually DO know better, through experimentation and experience, the optimal performance setting for your application. Let’s say, for example, you install Vortex Tubes on a line of your products, and a technician has to “dial it in” to a specific Cold Fraction.
Any Vortex Tube can be fitted with a drilled orifice (or “Hot Plug”) to replace the Hot Valve, which presets performance to a specific, non-adjustable value. If you know the Cold Fraction you need, it’s as easy as that. If not, it’s as easy as getting a stock Vortex Tube, setting the Cold Fraction where you want it, securing the Hot Valve in position (piece of tape works just fine,) and sending it in.
If you’ve got any other specific requirements – special materials, fittings, custom flow/temperature parameters, etc., give me a call; let’s talk.
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