How to Best Apply Vortex Tube Cooling

So, you have found yourself with a little bit of a conundrum. You need to cool a part but don’t know where to start and there are so many different options to choose from. In most cases when it comes to cooling with compressed air there are two different paths you can take. First is using a large volume of air at room temperature to blow across the surface area of the product. The other option is to use cold air from a vortex tube to drop the part’s temperature. In most case a large volume of air can be used to cool things down to relatively cooler temperatures; think cooling a cup of coffee using your breath. The issue you run into is when the temperature of the room air gets closer to the temperature you want to achieve in the end. In other words, when the temperature difference between your cooling air and your desired end temperature is small there is less cooling taking place with that same volume of air.

Mini Spot Cooler cooling down a bit used in milling plastic

This can be explained by looking at the cooling power formula:

Btu/hr = 1.0746*(CFM)*(Delta T)

In this case the Delta T is the difference between the temperature that you want to cool the product down to and the temperature of the air. This means the smaller the delta T is the higher the CFM flow will need to be to counteract the effect of the temperatures are so close to one another. Here are some examples of cooling a product and you are providing 1000 CFM of air to cool it.

Btu/hr = 1.0746*(1000 CFM)*(150F – 130F)

                Btu/hr = 21,492 Btu/hr

Btu/hr = 1.0746*(1000 CFM)*(150F – 100F)

                Btu/hr = 53,730 Btu/hr

As you can see the closer the Delta T is to 0 the less Btu/hr you get. Getting this kind of CFM flow is easy if you use something like EXAIR’s Super Air Knife or Super Air Amplifier. These systems take a small amount of compressed air and entrain the surrounding ambient air to increase the volume to a large blast. Take a look at model number 120022 which is the 2” Super Air Amplifier, this unit can produce 1,023 CFM while only using 15.5 CFM at 80 psig. But when you get close to cooling the temperature down to that room temperature or below it gets much harder; which only means that the temperature of the air being used to cool needs to be dropped. Dropping the air temperature can only be accomplished by using outside means like air coolers or in this case EXAIR’s Vortex Tubes and Spot Coolers.

EXAIR Air Amplifiers use a small amount of compressed air to create a tremendous amount of air flow.

Vortex Tubes and Spot coolers have some limitations. Generally they are not thought of products that produce large volumes of air (even though we make them up to 150 SCFM). And they are best suited for smaller areas of cooling, spot cooling, if you will. However, EXAIR Vortex Tubes do have one key feature that can help compensate for the lack of volume. LOW TEMPERATURE! The vortex tube can produce temperatures lower than 0F while stile retaining a good portion of air volume from the inlet.

Sub-zero air flow with no moving parts. 3400 Series Vortex Tubes from EXAIR.

For example, let’s look at model number 3240 running at 100 psig with 70% of the air from the inlet exiting the cold side (aka 70% cold fraction). At 100 psig the 3240 will use 40 SCFM at the air inlet and will have a temperature drop of 71F. If the compressed air has a temperature of 70F that means you will be seeing a temperature of -1F. Also, when using the 70% cold fraction you will see 28 SCFM of cold air flow. Now let’s plug those numbers into the cooling power formula.

 Btu/hr = 1.0746*(28 CFM)*(150F + 1F)

                Btu/hr = 4543 Btu/hr

As you can see, using a small amount of compressed air you can still net you a good amount of cooling if the temperature is lower. All in all, the best option for cooling products down to temperatures that are above ambient temperatures is something that can produce a large volume of air. For small areas that require cooling the product down to temperatures to ambient temperature and below, use EXAIR’s Vortex Tube.

If you have questions about our Air Amplifiers and Vortex Tubes, or would like to talk about any of the quiet EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR or any Application Engineer.

Cody Biehle
Application Engineer
EXAIR Corporation
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A Super Air Knife Benefits Aerospace Manufacturing

The aerospace industry has a high demand for high quality materials and can often be the leading users of high-quality materials. Since these sort of materials are typically very expensive it should be no surprise that manufacturers of aerospace parts are always looking for ways to gain efficiency within their processes. Today’s blog offers insight into how one aerospace company optimized its performance.

1 – Airplane Interior

A manufacturer of passenger plane interiors contacted us looking to improve their feed of material in and out of presses. They manufactured aircraft plywood and struggled with a hands-free way to help “float” the sheets during loading and unloading. They also spent a good amount of time waiting for the sheet to cool enough to handle for removal. These presses opened a minimal amount and were pressing the layers of the sheet together and then needed to be slid out of the press and moved on to the next process. The operators would use a handheld blowgun to try and blow under the sheet to move and adjust its positioning however they were then left with only one hand to do the positioning which became cumbersome. After the sheet was pressed they would blow with the same gun again and attempt to cool down the handling location and then drag it back out of the press. This was not a safe or efficient method to handle these sheets.

To improve the process this manufacturer installed a Super Air Knife. The opening on the press was 6′ wide, so they used a 72″ Super Air Knife w/ Plumbing Kit Installed Kit on one press as a test run. The knife was fed from a line that was outfitted with a solenoid valve that tied into a sensor already existing on their press so the air would only be fired when called for by the operator. While the knife did consume more air per minute of operation they were able to reduce the overall time air was being used for loading because the operator now had both hands to work with the sheet.

A 72″ Super Air Knife w/ Plumbing Kit Installed blowing debris off a part being laser cut.

Once the process was completed and the press opened the knife would turn on again to cool the sheet, then within a few seconds, the operator would reach in and again be able to easily float the sheet out. This was all made possible by the low profile design of the Super Air Knife not inhibiting the range of motion the operators had and not having to block the limited work envelope they had at the machine.

With this test machine improving production time, operator satisfaction, and enabling safer machine operation the company elected to implement a program installing the 72″ Super Air Knives on each one of their presses. If you would like to discuss any point of use compressed air application that needs improvement or isn’t as safe or efficient as you would like in your facility, contact an Application Engineer.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Timofejev, Aleksandrs – Turkish Airlines, TK015, Instanbul- Sao Paulo- Buenos Aires – 16 June 2013, retrieved from commons.wikimedia.org/wiki/File:Turkish_Airlines,TK015,_Istanbul-_Sao_Paulo-_Buenos_Aires-_panoramio.jpg

EXAIR’s Super Air Knife Replaces Blower-Driven Slotted Pipe

EXAIR’s Super Air Knives are the ideal fit for any application requiring a laminar “curtain” of air for blowoff purposes. The high-velocity airflow does an excellent job of cleaning off surfaces, cooling, and drying in a wide variety of applications throughout industry. These products are engineered to provide a consistent and reliable force across the full length of the knife, ensuring repeatable performance in any application.

I recently worked with a customer who manufactures a variety of bread products. In one application, they were using slotted pipes connected to a blower to clean sesame seeds off of trays after baking. The cut pipes seemed like a simple and economical solution since they had the materials there in the facility already, but the homemade blower-knives were lacking in force necessary to clean the trays.

Slotted pipes operating off of a blower didn’t quite pack the “punch” necessary to clean the trays.

When the tray wasn’t fully cleaned, residual seeds would stick to the bottom of the next loaves and burn leaving an unacceptable product for their customers. The solution was to implement a manual step of scraping off the trays which required a dedicated operator to perform this single operation. The plant runs 24/7, leading the customer to hire 3 new personnel strictly for cleaning the trays all day long.

Recent staffing difficulties due to COVID-19 led management to seek out areas where they could enhance their production efficiency and identified an opportunity in this application. EXAIR’s compressed air operated Super Air Knives provide a hard-hitting curtain of air that is very effective at cleaning. The (2) slotted pipes were replaced with (2) Model 110024SS stainless steel Super Air Knives and plumbed into their existing compressed air system.

Immediately, the higher force provided by the Super Air Knives displayed the ability to completely clean the trays and eliminate the need for dedicated operators for this part of the process. This allowed them to shift personnel to areas in the facility in desperate need of help, while still solving the problem of rejected bread loaves due to residual seeds.

If you have an application in your facility that is in need of an efficiency makeover, give us a call. Our team of experienced Application Engineers is ready to help evaluate your process and make any necessary recommendations.

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

Engineered Compressed Air Products = Less Noise & Money Saved

Everyone dislikes loud noises for the most part. Here in Ohio we just got done surviving the constant buzz and swarming of cicadas. We all deal with noise on a daily basis, some of it enjoyable and some of it not so much. Noise is an inescapable fact of life and all we can do is try to reduce noise level to save our sanity. But, did you know that cutting down on the noise produced by compressed air blow offs can actually save you money? Your loud homemade blow off system is not only way too loud, but it is most likely also costing you more money than you need to spend.

EXAIR’s engineered compressed air products are designed to operate quietly and efficiently. The reduction in noise they produce is only one of the benefits – another is the reduction in money by reducing compressed air use.

EXAIR Super Air Knife Promotion
EXAIR’s SUPER AIR KNIFE

But how does one calculate out the ROI? It is very simple to calculate out your potential savings of using one of EXAIR’s Intelligent Engineered Compressed Air Products. If you would rather not do the calculations out yourself then we can do it for you by sending the item in question to our Efficiency Lab Testing. The Efficiency Lab Testing is a free service that we offer to show you the possible savings by switching to one of our products.

The following is a typical ROI preformed and replaced with a corresponding EXAIR Super Air Nozzle:

  • ¼” drilled pipe with (3) 3/32” Holes which uses 9.4 SCFM per hole at 80 psig (denoted as DP)
  • A Model 110003 3” Super Air Knife can be used to replace and only uses 8.7 SCFM at 80 psig (denoted below as SAK)

Calculation:

(DP air consumption) * (60 min/hr) * (8 hr/day) * (5 days/week) * (52 weeks/year) = SCF used per year for Copper Pipe 

(28.2) * (60) * (8) * (5) * (52) = 3,519,360 SCF

(SAK air consumption) * (60 min/hr) * (8 hr/day) * (5 days/week) * (52 weeks/year) = SCF used per year for EXAIR Product 

 (8.7) * (60) * (8) * (5) * (52) = 1,085,760 SCF

Air Savings:

SCF used per year for DP – SCF used per year for SAK = SCF Savings

               3,519,360 SCF – 1,085,760 SCF = 2,433,600 SCF in savings

If you know the facilities cost to generate 1,000 SCF of compressed air you can calculate out how much this will cost you would save. If not, you can us $0.25 to generate 1,000 SCF which is the value used by the U.S. Department of Energy to estimate costs.

Yearly Savings:

                (SCF Saved) * (Cost / 1000 SCF) = Yearly Savings

                                (2,433,600 SCF) * ($0.25 */ 1000 SCF) = $608.40 annual Savings

With the simple investment of $216 (as of date published) you can calculate out the time it will take to pay off the unit.

Time Until payoff:

                (Yearly Savings) / (5 days/week * 52 weeks/year) = Daily Savings

                                ($608.40/year) / (5 days/week * 52 weeks/year) = $2.34 per day

                (Cost of EXAIR Unit) / (Daily Savings) = Days until unit has been paid off

                                ($216) / ($2.34/day) = 92.3 days 

As you can see it doesn’t take long for the air knife to pay for itself. You also get better overall performance as the Super Air Knife will provide a solid curtain of air. In the end you get to breathe a sigh of relief as no more jump scares and a loud hiss when you turn your air on. Who doesn’t like to save a little money and sanity, especially in these crazy times?

If you have any questions or want more information on EXAIR’s Air Knifes or like products. Give us a call, we have a team of application engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
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