Tag: cooling nozzle

Adjustable Spot Cooler Increases Production Output in a Medical Application

Published on by exaircorpLeave a comment

I was recently contacted by a plastics manufacturer who specializes in producing precision medical components. In this particular application they were pushing an ETFE tube onto a heated, flared forming pin. Once the tube is set onto the pin, they placed the assembly into a shroud where they used their shop compressed air running through a manifold split into separate lines to cool the part. This process was working but it takes approximately 1 minute so they called EXAIR looking for a way to reduce their cooling cycle time and increase their daily production.

I recommend they use our Adjustable Spot Cooler and plumb the cold air exhaust to their existing manifold. The Adjustable Spot Cooler incorporates a Vortex Tube to provide a specific temperature drop from the compressed air supply temperature. The output temperature and cold airflow can be easily adjusted using the control valve on the unit. Ducting the output flow would allow the cold air to distribute evenly, not only reducing the cooling cycle but also providing more dimensional stability to the finished product.

Please note, that we do not always recommend running cold air through a manifold because many times these manifolds are metal and simply act as a heat sink, which removes the cold temperature from the air stream. In this case, however, the manifold was made of plastic and the air lines to the formed tube assembly were short. The plastic material insulated the cold air and the short air lines running to the tube assembly also decrease the time the cold air has to lose heat. Applications with typical metal manifolds and longer air distribution lines are best served by using the Adjustable Spot Cooler directly on to the application and eliminating the manifold.

Adjustable Spot Cooler
Maintenance free, spot cooling device providing up to 2,000 Btu/hr. of cooling capacity.

This is just one example of how incorporating a Spot Cooling device into an existing application provided a more favorable end result. Don’t hesitate to give us a call and see how we can help improve your process too.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

Good Communication is Needed to Discover the Best Solution

Published on by Leave a comment

I had a call the other day about a Cabinet Cooler System that was not working properly. In talking over the problem, the customer decided a picture might help me understand what he was trying to explain, so he sent one for to me to look at it. When opened, the picture did not show what I expected. Instead of the EXAIR Cabinet Cooler System, I was looking at an EXAIR Vortex Tube mounted to the top of a cabinet. Further discussion revealed that I was talking to the maintenance manager and he had no idea who had installed this and for what reason. He only knew it was reported that 2 cabinets were having issues – one was continuously leaking (the initial call and picture) and one was not as cool as it should be. Now there were two problems!

Starting with the initial, the vortex tube was actually working as it should. It is supposed to “leak” air. Vortex tubes will push cool air out on one side and hot air out the other. Per the picture, this vortex tube was installed to allow the hot air to exhaust from the cabinet, thus it would “leak” air. In this case, the cabinet was cool, but to what standard? No one knew what temperature was to be maintained. The maintenance manager, and for that matter the workers who reported the defect, did not know what the device was or how it worked. After describing how a vortex tube functioned, I directed him to look at the EXAIR website for more information and adjustment instructions if needed. The manager was surprised, and happy, that it was actually working as it “should be” so he could take it off his To-Do list.

PLEASE NOTE: A Vortex Tube is typically recommended for cooling a small area (spot cooling) or small volumes of gas. We do not usually recommend them for cooling electronic enclosures, EXAIR’s Cabinet Cooler systems are the best choice for an enclosure. Cabinet Coolers will provide quick and easy installation while maintaining the NEMA integrity of the cabinet. They are preset to provide maximum cooling and efficiency, and they are available with a thermostat and solenoid to turn themselves on and off as needed to maintain a specific internal temperature.

Now to the second unit. Again, it was determined to be a vortex tube, not a cabinet cooler system as originally thought. This unit was deemed to be working since it was not “leaking” but the cabinet was not cool. To my thinking, this unit was NOT working and explained why. I informed the customer that they may need to check their supply pressure and/or look to see if the unit had been adjusted to the point that the hot end airflow had been closed which would produce cold air. He replied he would look into it and then mentioned that he would have a word with the workers reporting the defects and investigate who and why the installations were done in the first place.

Throughout the conversation, one question kept coming up . . . were these the correct tools for the application? I was unable to answer this directly. I passed on that EXAIR would normally recommend actual cabinet cooler systems. These would provide more control for what they were apparently trying to do (cool the cabinets) and also keep them dirt and moisture-free. However, without more knowledge of what the customer was truly trying to accomplish and insufficient data available, I suggested the manager seek more information and call us back. He agreed. Although the vortex tubes in this application are usually not the choice, we know not all applications are the same. If the environment was extremely hot or space exceptionally tight, a vortex tube may be the best answer.

In my eyes, and to a degree the customer’s, the conversation was satisfactory but may not have provided the most effective and efficient solution. More data was needed, more understanding of the applications, and a better plan of action instead of putting a bandage on the problem. Based off how we left at hang-up, I believe the maintenance manager will be doing a little digging into what is going on in his plant and I foresee a call back to discuss his the best option to cool the cabinets.

John Pinchek
Application Engineer
johnpinchek@exair.com
@EXAIR_JP

More on Vortex Tubes: Understanding Cold Fractions

Published on by Lee EvansLeave a comment
vortex tube
An EXAIR Vortex Tube

I had a conversation today through our online chat feature with a customer in the Middle East who needed a bit more understanding about Vortex Tubes.  The cooling power and instantaneous ability of a Vortex Tube offers ways to remove heat from applications, but the way the Vortex Tube works was a little misunderstood.  So, we went over the basics.

A Vortex Tube transforms a compressed air supply into a stream of hot and cold air.  As the compressed air enters into the Vortex Tube, it passes through a generator which causes the air to spin.  The airstream spins down the length of the Vortex Tube until it reaches a “brake”, whereupon it changes directions and begins spinning inside of itself, giving off energy in the form of heat.  The result is a stream of cold air at one end of the Vortex Tube, and a stream of hot air at the other.

But how can we adjust the flows and temperatures?

Adjusting the flow and cold air temperature from a Vortex Tube is as simple as turning the adjustment valve at the hot end of the unit.  This valve controls the “cold fraction” of the Vortex Tube, or, to put it more simply, the amount of air which will exit the unit at the cold end.

EXAIR Vortex Tube Performance Chart
EXAIR Vortex Tube Performance Chart

For example, if we were to set a Vortex Tube to an 80% cold fraction, 80% of the air consumed by the Vortex Tube would exhaust through the cold end of the unit.  If we take the same Vortex Tube and establish a 60% cold fraction, 60% of the consumed air will exhaust through the cold end of the unit.

Why is this important?

The cold fraction is important because at various cold fractions we will product varying temperature drops, even at the same operating pressure.  So, in the example above, if we have a Vortex Tube operating at 7 BARG, set to an 80% cold fraction, we can expect a temperature drop of 30°C (54°F), relative to the temperature of the incoming compressed air.

This means that if our compressed air temperature is 25°C (77°F), we will have an outlet temperature of -5°C (23°F).  If we take the same air supply and reduce the cold fraction to 60%, we will have a temperature drop of 48°C (86°F).

The caveat here is that when we reduce the air temperature, we also reduce the flow.  So, the colder the air temperature from the Vortex Tube cold end, the lower the volume of cold air.

When determining if a Vortex Tube is right for an application, it is important to consider all the variables (operating pressure, compressed air temperature, cold fraction, required cooling) when making a model number selection.

If you have any questions or concerns when considering a Vortex Tube, contact an EXAIR Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

Big Or Small, We’ve Got ‘Em All! Vortex Tubes, That Is

Published on by Russ BowmanLeave a comment

A couple of weeks ago, I wrote about using large Vortex Tubes for freeze sealing/plugging of pipes. Even though they’re our LARGE Vortex Tubes, they’re still WAY smaller than the liquid nitrogen rigs that are also prevalent for this application. Smaller, in this case, means easier to handle and quicker to set up (and break down.)

So, that’s a case where a smaller device is used to do the same job. Today, I wanted to examine the different sizes of Vortex Tubes that we offer, when the job itself is what’s changing in size.

The Large Vortex Tubes are specified when a high flow of cold air is needed. Like the aforementioned freeze seals. Or this one, published in our catalog:

This is a typical application for a Large Vortex Tube.
This is a typical application for a Large Vortex Tube.

Our Medium Vortex Tubes are the most popular – there are ten to choose from, depending on the cold air flow rate and temperature you’re looking for. These can produce temperatures as cold as -40°F (-40°C) when set to a 20% Cold Fraction (which is the percentage of total supply air that’s directed to the cold end) and cold air flows as high as 32 SCFM when set to an 80% Cold Fraction, which will produce a cold air temperature of about 20°F (-7°C). Some common uses are cooling ultrasonic welds and brazed joints.

The Medium Vortex Tubes are so popular, in fact, that they’re incorporated into our Adjustable Spot Cooler and Cold Gun Systems. They come ready-to-go with mufflers, cold air hose kits, and magnetic bases, so they couldn’t be easier to use.

The Small Vortex Tubes are great when very low flows are needed, or if compressed air supply is limited. These are specified for much smaller applications, like cooling the needle of a sewing machine, small drill bits, etc. You can also get one with a cold air hose & magnetic base…that’s the Mini Cooler System.

Another advantage that makes the Vortex Tubes a great choice for cold air production is their consistency and dependability. If you supply one with clean, dry air, it’ll operate just about indefinitely, maintenance free. And if you need a constant supply of air as a certain temperature, say, for testing a thermostat or temperature switch, a Vortex Tube is exactly what you’re looking for: the only things that’ll change the cold air temperature are the compressed air supply temperature & pressure…assuming you don’t change the Cold Fraction yourself, as shown here:

If you’ve got an application requiring cold air flow, give us a call. We’re eager to help!

Russ Bowman
Application Engineer
Find us on the Web
Follow me on Twitter
Like us on Facebook