Which Vortex Tube Do I Need?

Last week, I wrote a brief introduction to vortex tubes, titled One Item Generates ¼ Ton of Refrigeration and Fits in the Palm of your Hand.” In it I introduced the Vortex Tube and the other products made from Vortex Tubes: Cabinet Coolers, Cold Guns, Adjustable Spot Cooler and Mini Coolers. I also introduced the idea of a cold fraction.  Today, I want to talk about specific Vortex Tube models.

The flow from the cold side of the Vortex Tubeis characterized in two different ways. First, we characterize the air by ΔT (temperature drop) from the starting compressed air temperature. With a supply pressure of 100 PSIG, the drop in temperature can range from 54° to 123° Fahrenheit. Second, we characterize the flow of air in Standard Cubic Feet per Minute. The different models of vortex tube are design to provide a range of flows and temperature.

Vortex Tube Specification

Vortex Tube Specification Chart

When facing this list you have numerous choices that can be daunting. My priorities for selecting a Vortex Tube for a customer are twofold. First, you need the Vortex Tube that will work in your application. Second, I want to choose the model with the least amount of compressed air in order to solve their problem with the least amount of air possible. The smallest Vortex Tube is a model 3202. It also utilizes the least amount of compressed air, 2 SCFM. At 100 PSIG and an 80 percent cold fraction, it will produce a cold flow of 1.6 SCFM at 54° F  below your compressed air temperature. If your compressed air temperature is starting at 70° F, your cold temperature will 16° F. All of the Vortex Tubes will be able produce this same temperature drop, but depending on which Vortex Tube you use will determine the volume of flow produced at that temperature.

1.6 SCFM of flow 54° F below compressed air temperature will take 135 BTU/HR away from a small 100°F box, which is enough energy to cool a needle, a small sensor, or a tiny camera, but what if you have a bigger area you need to cool. Then you need to use a Vortex Tube that will produce more flow. The 3202, 3204, and 3208 will all produce air at the same temperature, but the 3204 and 3208 will produce more volume of cold air.  With the same parameters as above (100 PSIG of inlet pressure and 80 percent cold fraction) the 3204 will produce 3.2 SCFM of cold air and cool 275 BTU/Hr. out of a 100° F environment. The 3208 will produce 6.4 SCFM of cold air and cool 550 BTU/Hr. These larger Vortex Tubes could be used to cool a closed circuit camera in a hot environment or a small drill bit where coolant is prohibited or undesired. From here our product continue to produce more volume of flow and we can go up to our largest Vortex Tube, 3299 which will use 150 SCFM of compressed and cool up to 10,200 BTU/HR.

What if you have an application where you don’t need more air but 16°F  isn’t cold enough? Then you can adjust your cold fraction. Adjusting the cold fraction will allow you to increase the temperature drop. Opening the brass hot valve, will lower the cold fraction. As more air is allowed to escape out of the hot end of the Vortex Tube, the temperature and the flow rate of the cold flow decrease.  If you need to cool below a 50% cold fraction we recommend the 3400 series Vortex Tubes. At 100 PSIG this would occur when you need more than 100° F temperature drop.

Vortex Tubes can be used in a variety of cooling application. If you have any question about the topic discussed above please contact me or another application engineer.

Dave Woerner
Application Engineer
DaveWoerner@EXAIR.com
@EXAIR_DW

Chain-Chain-Change, Change Out That Drilled Pipe…

Life is full of change.  It might sound trite, but truer words were never spoken.  I used to get up around 6:30 on work days.  Now, thanks to my son’s middle school schedule, I’m usually seeing him out the door at that time.  Getting up earlier was certainly a difficult change at first, but it’s had its benefits.  Not the least of which is spending a little extra time with the boy in the morning.

One of our favorite things to do while eating breakfast is to watch the ‘How things are made’ types of shows. Of course, watching these types of shows with an engineer has its downside.  While we can usually explain exactly what’s happening in the process of whatever is being made, the problem is that we often do.  Meaning we wind up talking over the program, which, ironically, is one of my greatest pet peeves.  Speaking of change, guess that’s something I need to work on…

20141002_062454

At any rate, this morning we saw a show on making saltines.  At the sight of the copper pipe positioned near where the cracker dough comes off the die-cut wheel, I knew exactly what was up. ‘They’re using drilled pipe! That’s not safe and a HUGE waste of compressed air!  That’s the perfect application for a Super Air Knife!”  Guess watching these programs with an EXAIR engineer has an additional risk: We can get a little over-excited when we see OSHA violations and wastes of compressed air! I think I about made my son jump out of his gym shorts, but he’s watched these sorts of shows with me before.  He knew the risks…

Life is full of change, and while perhaps I can get better at not talking while the TV show is on, I doubt I’ll ever stop cringing at safety violations and wasting compressed air.  Do you have drilled pipe in your plant?  If so, you could be in violation of multiple safety standards and are definitely wasting money on compressed air.  EXAIR can help you minimize harmful noise levels and keep you in compliance with OSHA’s dead-end pressure standard. Please give EXAIR a call to begin saving air and increasing safety!

Dan Preston
Engineer-at-large
DanPreston@exair.com
1-800-903-9247

 

 

Help with Choosing an E-Vac Vacuum Generator

This is a pretty common question when it comes to Vacuum Generator use in pick-and-place application, and although we can’t boil it down to a simple table & formula based on mass (like we can with the Vacuum Cups themselves,) we can usually hone right in on it, if we have enough details of the situation. And, if questions remain, we can always test one to find out…we’ve got an Efficiency Lab.

That’s what I did, first thing this morning. I had the pleasure of speaking with a robotics instructor at a vocational school yesterday…his class was building a robot to enter in a competition, and one of the operations it needs to accomplish is picking up a golf ball and carrying it a certain distance.  This sounded like a great application for a small E-Vac Vacuum Generator, and, considering the potential leakage at the Vacuum Cup face from the dimples on the golf ball, my first instinct was to consider our Model 810002M E-Vac Low Vacuum (Porous Duty) Generator w/Muffler, and a Model 900766 Bellow Style Vacuum Cup, with a 0.73″ diameter face…our smallest, and ideally sized for a golf ball.  They, however, have a VERY limited supply of compressed air, so the difference between the Model 810002M’s compressed air consumption (2.3 SCFM @80psig) and the Model 800001M E-Vac High Vacuum (Non-Porous Duty) Generator w/Muffler (1.5 SCFM @80psig) was worth considering.  Also, we figured that they might be able to use a Model 900804 Check Valve, so the only time they’d need to supply air was to pick it up, and, possibly intermittently to maintain the vacuum.  So, golf ball in hand, off to the Efficiency Lab I went.  I also took our trusty video camera:

As you can see, it locked on to the golf ball instantly, and the Check Valve allowed the Vacuum Cup to hold the ball for over 13 seconds with no air flow to the E-Vac, proving that there isn’t much leakage at all past those dimples.  I suspect we’ll be seeing this robotics class team in the winner’s circle at the competition.

In most cases, the difference between 1.5 SCFM and 2.3 SCFM consumption may go unnoticed when picking a short-duration pick-and place vacuum generator.  The higher usage product’s supply pressure can always be regulated down to reduce compressed air consumption and use only what’s necessary to do the task…we, in fact, recommend that on ANY compressed air application.  In this case, though, it was worth finding out.

If you have a pick-and-place application that you’d like help with in selecting the right system, give me a call.

Russ Bowman
Application Engineer
(513)671-3322 local
(800)923-9247 toll free
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Pressure Profile: Where to Measure Your Air Pressure

Generic Layout drawing of compressed air piping system.

In order to fully understand how efficient your compressed air system may be, you will need to generate a system pressure profile at some point.   This is a list or diagram of what pressures you have in your compressed air system at specific locations, as well as the pressure required by all the demand devices on your compressed air system.

One of the reasons for the pressure profile is that you may have an application that is far away from the compressor but also highly dependent on a specific operating pressure.   You may also find an application that, due to pressure losses within the system, causes an artificially high pressure demand.

The list below gives the critical points for measuring your compressed air system profile.

  1. At the air compressor discharge. (If using multiple compressors, measure at each.)
  2. If dryers of any type are being used after the compressor measure downstream from the dryer.
  3. Downstream of each filter. (If a particulate filter and oil removal filter are being used it is best to measure downstream of each individual device.   This is to tell when you have more than a 5 psig pressure drop or a clogged filter.)
  4. After each intermediate storage device, such as receiver tanks.
  5. At the point just before the main line from your compressor room branches off to distribution.
  6. The furthest point of each header line you have installed.
  7. On both sides of every filter/regulator units that are at high pressure point of use applications.

To give you an idea of why it is so important to measure these locations, take a look at the blogs we have posted on pressure drop. (Link Here)  As you can tell by the list of blogs that comes up, pressure drop through piping can really cause a lot of wasted energy in your compressed air system.   If you can get a good base line measurement by utilizing a pressure profile then you can start the process to optimizing your compressed air system.

6 steps

The EXAIR Six Steps To Optimizing Your Compressed Air System.

 

If you would like to discuss this or any of the other 6 steps to compressed air optimization, feel free to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

One Item Generates 1/4 Ton of Refrigeration and Fits in the Palm of your Hand

One of the most powerful, peculiar and perplexing products in the EXAIR catalog is the Vortex Tube. The medium sized vortex tube can generate up to a ¼ ton of refrigeration and still fit into the palm of your hand. It can generate cold temperatures that are 129° Fahrenheit below the input compressed air temperature, without any moving parts. It provides effective cooling on a wide variety of industrial systems like electrical cabinets, cutting tools, grinding operations, setting hot melt glue and a number of other cooling processes.

The Vortex Tube is used in Cabinet Cooler Systems, Cold Guns, Mini Coolers and Adjustable Spot Coolers to utilize compressed air to create cold air for your application needs. The Vortex Tube uses a Ranque-Hilsch tube to create the cooling effect. This principle has been used since 1927 to generate hot and cold flows from a source of compressed air. For more information on the physics behind how the Vortex Tube operates, visit here.

Our units are designed to operate at inlet pressures between 20-120 PSIG. The vortex tube comes in three different sizes, small, medium and large. The small unit will use between 2 and 8 SCFM of compressed air when fed with 100 PSIG of compressed air. It can be used with pressures much lower, but the change in temperature will not be as great. Below is a chart listing the temperature drops and rises of the vortex tubes with respect to supply pressure and cold fraction.

Vortex Tube Performance Data

The Cold Fraction performance chart shows temperature drops and rises for a Vortex Tube.

To use Vortex Tubes intelligently, cold fraction needs to be defined. A cold fraction is the ratio of cold air flow to total air flow through the inlet of the Vortex Tube. This cold fraction is adjustable on the Vortex Tubes and Adjustable Spot Coolers, but it is preset on the Cabinet Cooler Systems and Cold Guns. Adjusting the cold fraction changes 2 variables with the Vortex Tube. First, it changes the amount of cold flow from the Vortex Tube. Second, lowering the cold fraction also lowers the cold air temperature. Flow and temperature will both determine the heat transfer of the system.  For tool cooling operations, a very high cold fraction is used.  If you have a tool that may be operating above 150 or 200° Fahrenheit, it will cool faster with more air flow at a higher temperature than air at sub-zero temperatures. For applications where the final temperatures are very low, below freezing or sub zero, lower cold fractions can be used.

Find the blog next week to find out about what the addition of generators affects on a Vortex Tube.

Dave Woerner
Application Engineer
DaveWoerner@EXAIR.com
@EXAIR_DW

Safety Air Gun Improves Aluminum Extruding Machining Process

I was doing some work around the house Saturday when I heard my wife shouting out from our laundry room….”Something is wrong with our dryer. This is the 3rd time I’ve restarted it and the clothes are still wet!”. Now having been in this situation before, I knew this meant that the exhaust was probably clogged with lint (again).

See, our laundry room runs parallel to our family room and the exhaust ducting goes up and then across the laundry room, across the family room and then exhausts on the side of the house. (I would like to find the person who thought this was a good idea!). I have thought about re-routing the ducting but the only other option would be to have the exhaust on the front of the house which will “never happen” (per my wife). So I usually end up taking my vacuum and attaching as many extensions as possible to reach as much of the ducting as I can. I have tried a few other methods with no success – like taking my leaf blower and, from the outside of the house, blow the lint back towards the laundry room and into a garbage can. (hint: make SURE your wife is not in the laundry room when attempting this…. They don’t react too well when they get covered in lint!)

This made me think of an application I worked on last week with an aluminum extrusion company. The customer cuts lengths of aluminum siding from 1’ up to 10’ in length and, standing at one end of the material, are using a standard blow gun to try and blow out the chips but are unsuccessful. They reviewed our website but were still unsure what product may fit their needs best, so they gave us a call.

We discussed their application and the customer was able to email pictures. After reviewing the pictures I recommended using one of our Soft Grip Safety Air Guns with our Model # HP1125, 2” Flat High Power Super Air Nozzle and a 72” extension.  The Soft Grip Safety Air Gun is constructed of cast aluminum and includes a hook for hanging in a convenient location. The Model # HP1125, 2” High Power Flat Super Air Nozzle, produces 2.2 lbs. of force @ 80 PSIG and utilizes 37 SCFM with a sound level of 83 dBA. This would also meet or exceed the OSHA standards for safety, per Standard 1910.242(b) for 30 psi dead end pressure, and allowable noise exposure per Standard 29 CFR – 1910.95(a).

HP1230

An EXAIR model HP1230 Soft Grip Safety Air Gun

To discuss your application or help with selecting the right product, contact an application engineer.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

EXAIR At BI-MU With Italian Distributor

Lee with Magugliani team

Myself, Lee Evans, with the Magugliani team.

I had the pleasure of attending the BI-MU exhibition with our Italian distributor, Magugliani SRL, from September 30th – October 4th in Milan, Italy.  BI-MU is an exhibition dedicated to the Italian machine tool, robot, and automation industries.  And, our distributor is very keen on finding relevant applications and solving problems in these industries.

Adjustable Spot Cooler

An EXAIR Adjustable Spot Cooler w/ Single Outlet Hose Kit.

One of the most frequent applications we discussed was the use of the Adjustable Spot Cooler.  During milling operations or in lathe turning applications, considerable heat is generated when the cutting edge is applied to the work piece.  This heat can cause the metal (or other material being machined) to adhere or even weld to the cutting edge or flute of a bit.  Such a  condition presents quality control problems, and loss concerns due to machine tool downtime.

The Adjustable Spot Cooler can remove these problems from a machining application using only compressed air – no liquid.  By directing extremely cold air (as low as -30F) to the machining area, the heat is removed and the useful time of the cutting edge is in increased.  By cooling the precise area generating the heat, the Adjustable Spot Cooler can boost the productivity and quality of parts coming out of a machine.

If you have a similar application, or think an Adjustable Spot Cooler may be a positive addition to your application, contact an EXAIR Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

**Thanks again to the Magugliani team for a GREAT exhibition!

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