The Last Of The Compressed Air Challenge Seminar Blogs (for now)

Last week, Lee Evans, Brian Farno, and I attended a seminar entitled “Fundamentals of Compressed Air Systems,” sponsored by the Compressed Air Challenge. Lee and Brian have already written great pieces on what we learned, and Joe Panfalone (even though he didn’t even go) has gotten in on the action too – leaving me to search desperately through my notes for something relevant to discuss. Here’s my initial takeaway: If your blog is published on Wednesday, try to attend the seminar you wish to write about on Tuesday, not Thursday.

One thing that my associates left me, though, was the subject of inappropriate uses of compressed air. According to the Compressed Air Challenge folks, 70% of the savings to be realized lie in measures on the “demand” side of your system. A big chunk of this is the aforementioned inappropriate uses, which were defined as applications that could be performed using alternate methods. The assumption is that these alternate methods are less costly from a compressed air usage standpoint – which is not always the only factor to consider:

*The floor needs to be swept at the end of the shift. It takes 10 minutes with a broom, or 5 minutes with a Super Blast Safety Air Gun (for instance, the Model 1214, which uses 91 SCFM @80psig). Let’s assume labor at a cost of $50/hr, and compressed air at a cost of $0.25/1000 SCF (Standard Cubic Feet):

-Broom: $4.17 labor (10 minutes @$25/hr) = $4.17
-Air: $2.19 labor (5 minutes @$25/hr) + $0.11 compressed air = $2.19

Other situations require a little more data, and math, to quantify. For instance, if vacuum is required for lifting, pick and place, mounting, etc., a central vacuum pump may have lower operating costs than those associated with the compressed air needs of E-Vac Vacuum Generators. When you factor in initial capital cost and maintenance expenses, the E-Vac still compares favorably, though, despite the potentially higher operating cost. I say “potentially,” because a system’s vacuum pump is often located some distance from the farthest point of use. That means it’s spending energy not only to provide vacuum to the remote points of use, but also to overcome the line loss in those lengths of piping. E-Vacs don’t have this problem, as they can be easily installed at the point of use, and sized appropriately.

The last (and I thought, most highlighted) inappropriate use they covered was cabinet cooling. It was explained that even though a vortex tube cooler may cost less, the air consumed will cost more than the electricity required by a refrigerant-based unit. Now, we don’t dispute that…the following comparison shows as much:

Then, the instructor went a bit further (pre-empting a question from Brian, Lee, and I) to validate cabinet cooling as an appropriate use, but only when: the environment was not conducive to a refrigerant-based unit (high ambient temperatures, dusty/dirty/aggressive atmosphere, etc.), AND thermostat control was used. They took great pains to not promote any particular brands of equipment in the presentation of the seminar, but the photo they used to illustrate this was unmistakably an EXAIR NEMA 4 Cabinet Cooler with Electronic Temperature Control. That was worth the price of admission for me.

If you have questions about whether you’re using your compressed air appropriately, or even to its maximum efficiency, give us a call. If we can’t find the answer mathematically from the data available, we can gather the data in our Efficiency Lab. Math doesn’t lie, and neither will we.

Russ Bowman
Application Engineer
EXAIR Corporation
(513)671-3322 local
(800)923-9247 toll free
(513)671-3363 fax

The Effect of Different Vortex Tube Generators on Cold Flow

A Vortex Tube cooling kit is helpful when flow and temperature requirements are unknown. The experimental kit affords you the flexibility to determine your cooling needs.

I recently had a customer e-mail me with this inquiry. Following is our discussion:


We have a small vortex (3208) and a set of generators, the one that is pre-installed in the Vortex Tube (8GR) and a few more:

2GR, 4GR, 2GC, 4GC, 8GC

Maybe you could tell me the effect of these generators on the cold flow.

My main application is to refrigerate tools during machining or cool ultrasonic transducers during continuous operation. My compressed air source is 6.5 BARG. Using the Vortex Tube as it comes, after closing the hot flow and opening it a revolution, I can reduce the temperature from 22ºC (room temperature) to -6ºC (measured in the cold air flow at the output). How do I use the flow generators?

Thank you for your question concerning the generators which are interchangeable on the Vortex Tube.  The purpose of the various sizes and types is explained as follows:

GC vs. GR designation: The GC type generators are designed to achieve maximum temperature drop for applications which may need an airflow which is below 0 degrees F. It is unusual that an industrial cooling application would need air this cold, but some scientific and other similar academic pursuits do need air flows that cold. The thing you give up when you try to achieve low cold temperature is the flow. Flow and temperature drop are inversely related to one another with a vortex tube’s function.

The GR type generators are used for temperatures down to zero degrees F. So, these would be the more prominently used generators for industrial applications. We usually will set up a Vortex Tube in a cooling application to have about 50 degree F temperature drop and can still preserve 80% of the total flow for cold flow applications. This is what we refer to as maximum refrigeration settings.

As for the numbers on each generator (2, 4 or 8) this is the indication of the amount of air volume consumed by the Vortex Tube when this specific generator is installed. The flow rate is indicated in SCFM with 100 PSIG inlet working pressure. So an 8 SCFM @ 100 PSIG flow rate is what is determined by an 8-GR or 8-GC generator. Small Vortex Tubes are available in flows of 2, 4 or 8 SCFM.

Basically, the larger your flow rate, the more cooling power you can generate. Think of the cold air as ice. Think of 8 SCFM as a 55 gallon drum of ice and a 2 SCFM as a 5 gallon bucket of ice. Both have the same temperature, but the 55 gallon size has potential to do more work to cool down a larger heat load.

Creating a spot of heat with a torch or an electric heating element is not hard to do with common tools found in a manufacturing environment. Creating a spot of cold air for similar situations is a very tough thing to do in the same situation. A Vortex Tube is a handy and convenient tool to allow for the spot cooling or small chamber cooling applications.

If you have a spot cooling application you think we may be able to help with, please contact us by e-mail, chat, Face Book, Twitter, phone or fax. We will be glad to assist.

Neal Raker, Application Engineer

Six Steps to Optimizing Your Compressed air Systems

With the advent of the “Green Movement”, there is a heightened awareness of energy costs. Compressed air is expensive but an essential commodity that cannot be eliminated.  Its use though can be monitored and reserved for those applications that make the most sense. Here are 6 steps to take to make the most efficient use of your compressed air.

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Measure air consumption to find the sources that use the most compressed air
You can use a flow meter or go by the manufacturer’s air consumption specifications. When you have identified your major sources of air usage, you need to evaluate more efficient alternatives like engineered air nozzles and jets.

Find and fix leaks in your compressed air system
Plants that aren’t maintained can easily waste up to 30% of their compressor output through leaks that go undetected. In plants with high noise levels, it is very difficult to locate leaks by merely listening for them. Most plant noise is in the normal audible range of human hearing while air escaping from a small orifice is ultrasonic. A  leak detector  will pinpoint leaks that you normally you would not be able to hear. Testing the various unions, pipes, valves and fittings can be done quickly and effectively at distances up to 20′ (6.1m) away!

Replace inefficient blow guns, air nozzles, and open pipe with engineered compressed air products
While open and drilled pipe are cheap to make, their inefficient use of compressed air is quite costly. The difference between the cost to operate an engineered nozzle vs. an open pipe are extremely dramatic.

Turn off compressed air when not in use

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Overall consumption can be reduced by intermittently turning the air on and off between cycles or between parts coming down a conveyor. For part ejection from a press operation, the air only needs to be on when the ram is in the open position. For parts traveling down a conveyor there is no sense in blowing air between the spacing of parts. Using a computerize flow control such as an electronic flow controller which is a photoelectric senor with a timing controller that limits compressed air use by turning it off when no part is present.

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Use intermediate storage of compressed air near the point of use.
A common mistake when low on air is to crank up the pressure at the compressor. That is a very costly mistake. Increasing system pressure by 10 PSI results in a 5% increase in energy. A better method is to install a storage tank at or near the point of use. This will store compressed air for those peak durations without having to increase the system pressure.

Control the air pressure at the point of use to minimize air consumption.

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The more pressure you put onto an orifice the greater the volume of air will pass through it. EXAIR highly recommends using a pressure regulator. Start off a low setting and increase the pressure until it just gets the job done. That way you are only using the amount of air required for the application.

If you would like some assistance in your compressed air energy conservation give one of our application engineers a call at 1-800-903-9247.

Available 8AM-5PM EST

Joe Panfalone
Application Engineer
Phone (513) 671-3322
Fax (513) 671-3363

Have You Ever Had a Bad Hookup?

Now that I have your attention I can assure you I am only going to talk about compressed air.  At a compressed air seminar I attended yesterday, I saw many images of poorly connected air lines and fittings. The majority of the cases I saw all boiled down to one common denominator.  See if you can find anything wrong with the pictures below and then we’ll get into it.

The first picture shows the easy way to hook up a regulator and make it easy to take apart.   The issue is the quick disconnects may make it easy to hook something up or take the regulator out for maintenance but you are also restricting your flow considerably.  If you were to hook a Soft Grip Safety Air Gun up at the end of the line you would be limiting the amount of air you can flow to the gun before it even gets to the regulator.   The correct way to plumb this system would be to have a larger supply line and then have the regulator as close to the point of use as possible.  Also if you are setting all the regulators throughout your facility to the same point, i.e. 80 PSIG, then why pay to generate more at the source.  Reduce your compressor output to 80-90 PSIG.

The second picture has a lot going on and again the main problem here is all the leech hoses from the manifold are the same size, if not bigger than the supply line.  Not to mention the line that goes from one port on the manifold back to another port on it.  This means as soon as you turn on one leg of that manifold you might be at the capacity for that line and starving other processes.

The answer isn’t installing more compressors, the answer is to utilize the compressed air wisely making sure your system is plumbed properly.   We preach it every day here and can’t stress it enough.  If you have questions about your compressed air application or how to approach it, don’t hesitate to contact us.

Enjoy the weekend everybody!

Brian Farno
Application Engineer

Compressed Air Challenge

A few of us in the engineering department are attending the Compressed Air Challenge today.  The Compressed Air Challenge is a seminar which highlights the operation and optimization of compressed air systems.  Being that those subjects go hand in hand with EXAIR products and practices, we hope to not only attend and learn, but to contribute, given the opportunity.

One of the subjects to be covered is the impact of different compressor controls.  Many compressors use feedback control systems to either throttle the amount of intake air supplied to the compressor (known as modulating system control or throttling), or to reduce the compressor displacement/speed to accommodate for system load ( known as variable displacement/variable speed control, respectively).

These optional control systems can save energy costs by responding in real time to the needs of the system.  For example, if a compressed air flow of 100 SCFM at 80 PSIG is required for 2 hours of the workday and after this initial use only 50 SCFM at 80 PSIG is required, a variable speed compressor can accommodate for this change by adjusting the speed of the electric motor driving the compressor.  In this example the motor speed will lessen and the required electrical demand to product the required compressed air will lessen as well.  All the while, maintaining adequate compressed air pressure and flow.  I’m looking forward to learning more about these feedback systems.  These control systems do the same thing as an EXAIR product, they optimize and save compressed air costs!

If you have any questions about your compressed air applications or how EXAIR can fit into your current system, give us a call.

Lee Evans
Application Engineer

Atomizing Nozzles: Common Questions About Viscosity

As EXAIR Atomizing Nozzles become more popular with our customers, we are getting a lot of interesting questions that folks have regarding the nozzles themselves and the information that we provide so the customer can make an informed decision.

One set of questions has to do with the flow rate information presented in our technical data for the Atomizing Nozzles. The question is, “What is the fluid that is being used to derive your flow data given in the charts?”  That answer would be plain old water (H2O).  The next question that comes is, “What if my fluid has a higher viscosity? How do I figure out the flow rate that will apply to that?”

The answer is that you will not know until you actually perform a test with your specific material. However, if you apply some simple logic to the question, a higher viscosity fluid is going to flow less than water through an Atomizing Nozzle. So, to compensate, you can select an Atomizing Nozzle size which has a higher water flow rate in order to compensate for a thicker fluid. A chart for viscosity of common fluids can be accessed here.

You do have options in terms of which style of Atomizing Nozzle you choose for the application. For example, fluids that have viscosity up to 200 centipoise can work well with either a siphon type or an internal mix type Atomizing Nozzle (an internal mix type can work with viscosity up to 300 centipoise). The siphon nozzle option is for applications where the fluid is not pressurized but is available from a nearby container (this can also be set up to be gravity fed type depending on the height of the fluid in relation to the nozzle). The internal mix nozzle is used when the applied liquid can be pressurized by a pump or perhaps by a pressure pot.

For applications where the fluid is over 300 centipoise, an external mix Atomizing Nozzle is the suggested product to use. Because the air and the pressurized fluid mix out in front of the nozzle, the liquid is not subject to the back pressure present upon it in an internal mix nozzle configuration. Therefore, the liquid pressure and air pressure are completely independent. This means a much higher pressure can be used on the high viscosity fluid to push it through the nozzle and be atomized.

The variety of nozzles available with different configurations, flow rates, spray patterns and abilities can be a little difficult to navigate without some help. That is expressly why we are here.  To help customers determine what they need in this range of product.

If you have been considering an Atomizing Nozzle for an application, please let us know if you have any questions or just want to talk things over to make sure you are headed in the right direction. We are here to help make the decision an easy one.

Neal Raker, Application Engineer

American Machine Tools – Yesterday and Today

Early Bullard Machine

I just came back from the IMTS show where I saw lots of machine tools and new innovations. Having been in the industry for 40 years, I could not help but think of all the company names that I was familiar with over the years that are no longer the stars of the show. Names like Blanchard, Bliss, Bullard, Le Blonde, Kearney & Trecker, Acme Gridley have been become more or less memories of Americana.What is most interesting to me is the history of these companies and their founders. Do a little research on the internet and you will find their founders were innovators and entrepreneurs who gave birth to the term “Yankee Ingenuity” The machine tool industry is what propelled the American economy. And with unfettered freedom to pursue and develop an idea, America became the world’s leading economy.

Some companies may have come and gone, but American exceptionalism still persists despite all the social and political discourse. This was quite evident from all the exhibits at the show. I witnessed vision systems that control the process to perfection, tool bits of exotic materials improving machinability, laser cutters capable of cutting the shell of an egg without breaking it. It was obvious to me, that with american ingenuity, what were challenges are now opportunities.

Modern Bullard Machine

We at EXAIR would like the opportunity to assist you with your compressed air challenges. Give one of our application engineers a call 1-800-903-9247 and experience what we can do for you.

Joe Panfalone
Application Engineer
Phone (513) 671-3322
Fax   (513) 671-3363