Finding and Fixing Leaks in Your Compressed Air System

I had to find and fix some leaks this week – in my yard. See, my underground storm sewer pipe, that carries my basement sump pump discharge and my house’s gutter drains to the street, was leaking.

The evidence was clear…swampy puddles were developing in my neighbor’s yard.

The location was clear…several patches of grass in MY yard were WAY more green and vibrant than the rest.

The cause was NOT clear…until I dug up those patches of the best looking grass my lawn has ever seen. Turns out, my maple tree’s (the showpiece of my front yard) root system found a way to penetrate one of the couplings in the sewer pipe, where it prospered into this:

That’s about 8ft worth of root growth that was clogging my drain pipe, and causing leaks upstream. My maple tree is not shown in the picture because my maple tree is a real jerk.

Two days worth of digging up and reinstalling pipe later, and all is well.  I mean, except for filling the trench, sowing some new grass seed, watching the birds eat it, sowing some more, etc.  Ah, the joys of home ownership…

I tell you all this, dear reader, so you know that I. Don’t. Like. Leaks…whether they be in my storm sewer pipe or in your compressed air system…which brings me to the (real) subject of my blog today.

Unlike the visual indications of my yard leak, compressed air system leaks don’t really draw much attention to themselves.  Unless they grow quite large, they’re typically invisible and very quiet…much too quiet to be heard in a typical industrial environment, anyway.  Good news is, they’re not all that hard to find.

One way is to use a soap-and-water solution.  You just need a spray bottle, some dish soap, and water.  Spray it on the piping joints, and all but the smallest, most minute, of leaks will create soap bubbles…instant indication of air leakage.  This method is inexpensive and simple, but it does tend to leave little puddles all over.  Plus, if your header runs along the ceiling, you’re going to have to get up there to do it.  And unless you can easily maneuver all the way around the pipe, you can miss a leak on the other side of the joint. If you have a small and relatively simple compressed air system, and all your piping is accessible though, this method is tried and true.

For many industrial compressed air systems, though, the limitations of the soap bubble method make it impractical.  But I’ve got more good news: those silent (to us) air leaks are making a real racket, ultrasonically speaking.  And we’ve got something for that:

EXAIR Model 9061 Ultrasonic Leak Detector discovers and pinpoints leaks, quickly and easily.

See, when a pressurized gas finds its way through the narrow (and usually torturous) path out of a slightly loosened fitting, worn packing on a valve, etc., it creates sound waves.  Some of those ARE in audible frequencies, but they’re often so low as to be drowned out by everything else that’s happening in a typical industrial environment.  Those leaks, however, also create sound waves in ultrasonic frequencies…and EXAIR’s Ultrasonic Leak Detector takes advantage of that ultrasonic racket to show you where those leaks are, as well as give you a qualitative indication of their magnitude.  Here’s how it works:

Find leaks and fix them.  This is Step #2 of our Six Steps To Optimizing Your Compressed Air System.  If you’d like to find out more, give me a call.

Russ Bowman
Application Engineer
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Discharge of Air Through an Orifice

My Application Engineer colleagues and I frequently use a handy table, called Discharge of Air Through an Orifice. It is a useful tool to estimate the air flow through an orifice, a leak in a compressed air system, or through a drilled pipe (a series of orifices.) Various tables and online calculators are available. As an engineer, I always want to know the ‘science’ behind such tables, so I can best utilize the data in the manner it was intended.

DischargeThroughAnOrifice

The table is frequently found with values for pressures less than 20 PSI gauge pressure, and those values follow the standard adiabatic formula and will not be reviewed here.  The higher air pressures typically found in compressed air operations are of interest to us.

For air pressures above 15 PSI gauge the discharge is calculated using by the approximate formula as proposed by S.A. Moss. The earliest reference to the work of S.A. Moss goes back to a paper from 1906.  The equation for use in this table is-EquationWhere:
Equation Variables

For the numbers published in the table above, the values were set as follows-

                  C = 1.0,      p1 = gauge pressure + 14.7 lbs/sq. in,    and T1 = 530 °R (same as 70 °F)

The equation calculates the weight of air in lbs per second, and if we divide the result by 0.07494 lbs / cu ft (the density of dry air at 70°F and 14.7 lbs / sq. in. absolute atmospheric pressure) and then multiply by 60 seconds, we get the useful rate of Cubic Feet per Minute.

The table is based on 100% coefficient of flow (C = 1.0)  For well rounded orifices, the use of C = 0.97 is recommended, and for very sharp edges, a value of C = 0.61 can be used.

The table is a handy tool, and an example of how we use it would be to compare the compressed air consumption of a customer configured drilled pipe in comparison to that of the EXAIR Super Air Knife.  Please check out the blog written recently covering an example of this process.

If you would like to talk about the discharge of air through an orifice or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Finding Leaks and Saving Money with the Ultrasonic Leak Detector

Locate costly leaks in your compressed air system!  Sounds like the right thing to do.

The EXAIR Ultrasonic Leak Detector is a hand-held, high quality instrument that is used to locate costly leaks in a compressed air system.

Ultrasonic sound is the term applied to sound that is above the frequencies of normal human hearing capacity.  This typically begins at sounds over 20,000 Hz in frequency.  The Ultrasonic Leak Detector can detect sounds in this upper range and convert them to a range that is audible to people.

When a leak is present, the compressed air moves from the high pressure condition through the opening to the low pressure environment.  As the air passes through the opening, it speeds up and becomes turbulent in flow, and generates ultrasonic sound components. Because the audible sound of a small leak is very low and quiet, it typically gets drowned out by by surrounding plant noises, making leak detection by the human ear difficult if not impossible.

ULD_Pr
Detecting a Leak with the Ultrasonic Leak Detector

By using the Ultrasonic Leak Detector, the background noise can be filtered out and the ultrasonic noises can be detected, thus locating a leakage in the compressed air system. There are (3) sensitivity settings, x1, x10, and x100 along with an on/off thumb-wheel for fine sensitivity.  The unit comes with a parabola and tubular extension for added flexibility.

ULD_Kit
Model 9061 – Ultrasonic Leak Detector and Included Accessories

Finding just one small leak can pay for the unit-

A small leak equivalent to a 1/16″ diameter hole will leak approx 3.8 SCFM at 80 PSIG of line pressure.  Using a reasonable average cost of $0.25 per 1000 SCF of compressed air generation, we can calculate the cost of the leak as follows-

Capture

It is easy to see that utilizing the Ultrasonic Leak Detector, and identifying and fixing leaks is the right thing to do.  It is possible to find and fix enough leaks that a new compressor purchase can be avoided or an auxiliary back-up is not needed any more.

If you have questions regarding the Ultrasonic Leak Detector, or would like to talk about any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Monitoring Is Apparently The New Thing To Do

Over the past month, I have been loosely watching the events revolving around a former government contractor, Edward Snowden.   The contractor leaked classified information about how the NSA monitors the US citizens.   This has of course brought on a large amount of news coverage and lots of questions from the US citizens to the government.  Others have been able to turn it into a laughing matter like Jimmy Kimmel did on his show.   Below is the commercial Jimmy did for the NSA on his show.

So with all the talk about how every little thing you do is monitored, and I am probably going to end up on several lists for keywords in this blog, why not begin your own monitoring campaign.

dataloggerPRce_559widesrd

EXAIR offers a full line of monitoring devices for your compressed air system, after all it’s the first step in the 6 Steps To Compressed Air Optimization.  The best part of our offering is that you can not only use the EXAIR Digital Flowmeter to monitor your compressed air system, when combined with the Summing remote display and/or the USB Data Logger, you can also collect the data from the meter.

The complete setup will allow you to easily see, and calculate, your cost savings before and after you implement an Intelligent Compressed Air product.

If you have any questions on how EXAIR can help you monitor your compressed air system, give us a call, chat, fax or e-mail.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Holey Leaky Air System Batman! I mean Prof. Penurious!

Well weekly blog readers, it is now time for poll two of six in our effort to see how many of our readers can benefit from our 6 Steps to Optimizing Your Compressed Air System.   If you noticed the results from last week’s blog, quite a few of our readers could benefit from our Digital Flowmeter and Summing Remote Display to get them on the path to an optimized compressed air system.  Now it’s time to see how many of our blog readers can say they run a tight air system.    So now for the poll.

Step 2 in our process is to find and fix the leaks in your compressed air system.   If you do a quick search on the all mighty Interwebs for “compressed air leaks”, you will find numerous articles on the matter.  This link will take you to an article from the Department of Energy that will help you get an idea of the average cost savings that you would see if you were to fix the leaks in your system.  From simply fixing 10 leaks in one compressed air system a company could save $57,069.  That is a lot of dough, not to mention this was from only 10 leaks in a system.  Every time you have a joint or connection in a system there is a possibility for a leak.   The size of the leak will determine how much money you are losing to it.  The best way to handle the leaks is to find them and permanently eliminate them.
The leak detection can be done in many ways; the method we offer is with the use of our Ultrasonic Leak Detector.  The ULD can detect leaks up to 20’ away and is also accurate even in a noisy industrial environment.   If you fix just one 1/16” diameter or equivalent leak, you will pay for the ULD in a year.  Not to mention the number of other leaks it will allow you to find and repair.  The amount of air you save by fixing the leaks will also be measured easily if, you are using our Digital Flowmeter from the previous blog

Once again, it is time for the blog to end.  Don’t forget to chime in on the poll and check back next week for step three in our blog series.
If you would like to discuss any of the information in today’s blog please do not hesitate to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
Twitter: EXAIR_BF