Tag: cold air cooling

EXAIR Mini Cooler™: Overview 

Published on by johnball2014Leave a comment
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

EXAIR Vortex Tubes: As Much Cold Air As You Need, As Cold As You Need It

Published on by Russ BowmanLeave a comment

If you’re looking for a reliable, consistent flow of cold air, there’s really no better way to produce it than with a Vortex Tube. There are no moving parts…the air flow and temperature from a particular model, set to a specific cold fraction, is only influenced by the compressed air supply pressure & temperature.

Pressure is easy to control…all you need is a suitable regulator.  Temperature CAN be a variable, depending on your type of compressor, if you have a dryer system (and what type it is,) and sometimes, ambient conditions…if, for example, a long pipe is run through a very hot environment like a foundry or a blast furnace operation.  In cases where supply pressure and/or temperature can be limitations, a higher capacity Vortex Tube, set to a lower Cold Fraction, may be specified.  Which brings me to the user inquiry that inspired today’s blog…

This particular customer uses our Model 3215 Vortex Tubes (15 SCFM, 1,000 Btu/hr) to provide cooling to analyzer systems that monitor certain quality parameters in their manufacturing processes.  The ability to precisely control the temperature in these systems makes for repeatable and accurate measurement of these parameters.   Their compressed air supply in this area is regulated to 80psig, they have a refrigerant-type dryer and climate-controlled facility, so their supply temperature is a consistent 70°F.  You couldn’t ask for better conditions for a successful Vortex Tube application, and they’ve worked great, for years.

Now, due to a plant expansion, they’re installing some of these analyzer systems in a location where the compressed air supply is limited to 60psig.  The required cooling capacity is going to be the same, so the Project Manager reached out to us to see if they could get the same amount of cooling with this new pressure limitation.  Here’s how they’re doing it:

We publish the rated performance of Vortex Tube products for a supply pressure of 100psig.  The Model 3215 Vortex Tube consumes 15 SCFM @100psig and, when set to an 80% Cold Fraction (meaning 80%…or 12 SCFM…of the 15 SCFM supply is directed to the cold end,) the cold air will be 54F colder than the compressed air supply temperature.  Here’s the performance table, so you can follow along:

EXAIR Vortex Tube Performance Table

Now, their supply is at 80psig.  Since air consumption is directly proportional to absolute supply pressure (gauge pressure PLUS atmospheric, which is 14.7psi at sea level,) we can calculate their units’ consumption as follows:

(80psig + 14.7psia) ÷ (100psig + 14.7psia) = 0.83 X 15 SCFM (@100psig) = 12.4 SCFM (@80psig)

So, with a 50°F temperature drop (from a supply @70°F,) they were getting 12.4 SCFM of cold air at 20°F.

As you can see from the table above, they’ll only get a 46°F drop at 60psig…and the flow won’t be as high, either.  So…we’ll need to get more air through the Vortex Tube, right?  Let’s use a little math to solve for what we need.

We still need 20°F cold air from 70°F compressed air, so, at 60psig, we’re looking at a Cold Fraction of ~70%.  And we still need 12.4 SCFM, so:

12.4 SCFM ÷ 0.7 = 17.7 SCFM @60psig (required supply)

Our Model 3230 Vortex Tube uses 30 SCFM @10opsig…at 60psig it’ll consume:

(60psig + 14.7psia) ÷ (100psig + 14.7psia) = 0.65 X 30 SCFM (@100psig) = 19.5 SCFM (@60psig)

That’s about 10% more flow than they needed, theoretically, which was close enough to start.  From there, they “dialed in” performance by regulating the supply pressure and Cold Fraction (see video, below):

If you’d like to find out more, or work through a cooling application, give me a call.

Russ Bowman
Application Engineer
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Vortex Tube Cooling: One Vortex Tube, Multiple Targets, Will This Work?

Published on by Neal RakerLeave a comment

VortexTubes

I had this question posed to me the other day. The customer asks, “I have three, small, enclosed spaces that are all within about five feet of each other. I’d like to put vortex tube cooling into each space. Can I do it with one vortex tube or will I have to use three of them?”

Imagine if you will, the cold air output of a single vortex tube being split three ways and ducted into each of these small chambers. While it is definitely technically possible to do, it isn’t always a feasible idea from the point of view of lost cooling power. Also, anytime that you can split up the effect you are trying to create whether that be cooling with a Vortex Tube or blowing off a large target that has many features to it, generally it is better practice to divide the application solution up to be applied over multiple, smaller units rather than one large one.

In this customer’s case, he wanted to save money on the purchase of multiple vortex tubes by purchasing one model 3230 vortex tube and plumbing the cold air output to his three cooling chambers. The problem is that the ambient temperature outside the boxes is rather hot and also contains high humidity. How exactly is this a problem?  You might ask. The problem is in all of the heat lost in cooling down the cold air distribution pipe (the pipe, hose or tube delivering the cold air into the chambers) that lies outside each box. That results in a net temperature gain (higher temperature) of the cold air you are trying to use for cooling the chambers or enclosures. With that lost cooling power, the customer runs a risk of not having sufficient cooling power to offset the heat load in each chamber. There is also the issue of back-pressure being presented to the Vortex Tube itself from the cold air distribution piping. When subjected to back-pressure, vortex tubes will lose their cooling capacity. Finally, there is the problem of getting equal cooling power delivered to each chamber. In this case, the solution of piping cold air to each chamber would cause an un-even distribution of the cold air with the closest chamber receiving the lion’s share of the cooling, leaving the other two under-cooled.

So, what is a better way to do this?  The method I suggested to the client was to use three of our model 3208 (8 SCFM) vortex tubes, allowing for direct connection of the vortex tube cold air output to each chamber. The cold air no longer has to cool down the cold air piping thus leaving more cooling power for each chamber, there is no back-pressure issue, and finally and probably most importantly would be the total air consumed would only be 24 SCFM in this case (3 x 8 SCFM) vs. 30 SCFM with a single larger vortex tube. That is a 20% savings on compressed air use in a straight up comparison. Depending on how many hours a day the system would be used, the difference in purchase price could be made up by lower operating cost in less than a year.

Neal Raker
Application Engineer
nealraker@exair.com