Post on 30-Jul-2021
TECHNOLOGY REPORT
COMPRESSED AIR: Tools, Tips, and Best Practices
TECHNOLOGY REPORT: Compressed Air 2
www.plantservices.com
TABLE OF CONTENTSMake the right demand-side hardware choices for your application 3The right nozzle can make a big difference to the total cost of compressed air system ownership
Something in the air: Ultrasound for compressed-air leak detection 8Here’s how to use airborne ultrasound to identify leaks and reap big saving
3 steps to better compressed air system design 13Spend some time and attention up front to prevent major headaches later
How much do you know about the vortex tube? 16Follow these guidelines to get the most heating and cooling out of your vortex tube application
Med school for compressor techs 22How the IoT and Big Data are helping new engineers and technicians get up to speed
AD INDEXEXAIR • www.exair.com 7
UE Systems Inc. • www.uesystems.com 12
Kaeser Compressors Inc. • www.us.kaeser.com/ps 15
ITW Vortec • www.vortec.com 21
Sullair • www.sullair.com 25
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TECHNOLOGY REPORT: Compressed Air 3
Nozzle design for applying air in
industrial applications has seen
considerable change over time.
Much of the change, particularly in recent
years, has been driven by shops’ realiza-
tion of the value that nozzles can provide to
their operations.
In the past, a company would often choose
the method with the least expensive ini-
tial cost, with little concern about the big
picture. Air delivery might be as simple as
putting holes in a pipe or running a copper
tube to the required location.
As customers began to realize these meth-
ods were costing extra money over the life
of the item, OEMs became more in touch
with concerns for total cost of ownership.
New product designs began addressing is-
sues beyond the purchase price, such as in-
stallation time, energy consumption, effect
on the production process, maintenance
requirements and replacement parts.
THOUGHTFUL SELECTION“People often think choosing a nozzle is an
easy decision,” says Bryan Peters, president
of EXAIR Corporation (www.exair.com).
“They think as long as they get something
big and powerful enough, it’ll get the job
done. But air nozzles are available in a large
variety, and taking the time for research or
relying on an outside source for expertise in
determining how to most effectively main-
tain an efficient and proper blowoff can save
a company a lot of money in the long run.”
When shopping for a nozzle, a company
should be prepared with as much infor-
Make the right demand-side hardware choices for your applicationThe right nozzle can make a big difference to the total cost of compressed air system ownership
By Brian Farno, Exair
www.plantservices.com
TECHNOLOGY REPORT: Compressed Air 4
mation as possible about the process in
which the nozzle will be used, the weight
of the parts, the speed of the operation,
and any other available details that could
influence the nozzle’s performance. This
information will help in choosing the best
nozzle for the application. A little addi-
tional time spent in putting together such
data can go a long way in selecting the
right nozzle.
WHY CHANGE?As companies push to ever leaner process-
es, they are trying to fit more operations
into less space. One of the ways nozzle
manufacturers are helping to meet this goal
is in offering compressed air products with
a smaller space requirement, allowing multi-
stage operations within a smaller footprint
and optimizing the performance within the
required space.
Another consideration that is often over-
looked in the purchase of air nozzles or
even the decision of whether or not to
replace existing ones is compliance with
current or upcoming safety regulations.
While many nozzles manufactured today
meet safety standards, such as OSHA
1910.242 (for dead-end pressure regula-
tion), Kirk Edwards, director of sales and
marketing at EXAIR, estimates that close
to 50 percent of all current installations
still are unsafe, old, legacy designs, and
not everyone has replacement on their
radars yet.
“Many of these legacy systems are incred-
ibly durable, but they’re also unsafe, highly
inefficient and loud,” Edwards says. “But
people continue with the notion that if it’s
not broken, don’t fix it. We understand that
people are really busy, but reduced energy
consumption and noise levels in addition to
increased safety for the personnel should
be a consideration in any blowoff applica-
tion. Once cost of ownership creeps into
the conversation, it’s pretty easy to justify
the upgrade. Payoff could be less than a
week in some cases and less than a month
in most.”
Another reason to consider upgrading a
system is energy savings. About 70 percent
Figure 1. Air nozzles come in many shapes and sizes to perform in an endless variety of applications. Determining the right fit is key to significant long-term savings.
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TECHNOLOGY REPORT: Compressed Air 5
of simple nozzle blowoff applications are
overpowered; people typically don’t need
as much force as they think the need to get
the job done. Sometimes the same nozzles
are used for multiple applications, so a shop
will often overpower to cover the extreme
cases. Also, local energy companies in near-
ly every state offer programs to pay incen-
tives to utility customers for replacing open,
inefficient blowoff systems with engineered
air nozzles.
EFFECTIVE AIR DELIVERYBeyond the energy and production ef-
ficiencies that an upgraded air nozzle
system can bring to a shop, a number
of design features should be considered
when determining the best fit for an appli-
cation. Material of construction can play an
important role in performance and durabil-
ity. Many nozzles are made of brass, alumi-
num or plastic. While these are lightweight
and can be relatively inexpensive, they
might not hold up to the rigors of every-
day use in certain applications. Aluminum,
for instance, can deteriorate quickly when
exposed to DI water or detergents. Stain-
less steel, on the other hand, can hold up
to corrosion much better.
“It comes back to total cost of ownership,”
Peters says. “What’s cheapest today might
Figure 2. In this part stamping application where lubricant and slugs needed to be removed, engi-neered compressed air nozzles lowered air consumption and noise levels by replacing open pipes.
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TECHNOLOGY REPORT: Compressed Air 6
not be cheapest in the long run. And as
a nozzle gradually wears out, people will
often hold onto it for too long, oblivious to
the fact that its poor performance is costing
them significant amounts of money.”
For some applications, though, strong
metal materials may pose a risk of dam-
aging the surface of the products being
produced should they come into contact.
Particularly in a manual blowoff process
of sensitive materials such as lenses, mir-
rors, medical products, and so on, plastic
nozzles could be the better option.
Another consideration is the preparation of
the air that will be going through the system.
If the production process requires a clean
environment, the air must be clean as well.
Filtration of the air prior to delivery is the
key. And although nozzles may be designed
to endure certain size particles, the end
product might not be able to withstand it.
Positioning of the nozzles is also an impor-
tant factor in the system’s effectiveness. “A
lot of people think they can just point the air
at the product from any distance or direction
and it will work,” Edwards says. “But you re-
ally need to be aware of how you’re attack-
ing the process, and an experienced manu-
facturer can provide a lot of insight into the
best nozzle positioning for an application.”
Seeing these processes first-hand helps to
analyze the situation and determine the
best solution, but often you can record
images and videos and send them to your
supplier in order to demonstrate your
situation. There are even times when the
nozzle can be too close, as many products
bring in surrounding ambient air at the
exit of the air flow. If it’s too close the ex-
tra volume, which can be helpful in some
blowoff and cooling applications, cannot
be brought in.
“We try to encourage more customers to
enlist the help of experts,” Peters says.
“We don’t expect everybody to know
everything, even about their own process.
They have their hands full fixing things
and making sure things work. They have
their own areas of expertise. They don’t
need to be the experts on nozzles.”
Brian Farno is an Application
Engineer with EXAIR (www.
exair.com) and has been with
the company since 2010. He
holds a B.A. in mechanical
engineering and a Green Belt in LEAN Manufacturing,
and has 5 years of experience with CNC metal cutting
machinery. For more information from EXAIR about
nozzles and other compressed air products, call 513-
671-3322, email an application engineer at techelp@
exair.com or visit EXAIR.com.
11510 Goldcoast Drive • Cincinnati, Ohio • 45249-1621 • (800) 903-9247 fax: (513) 671-3363 • E-mail: techelp@exair.com • www.exair.com
www.exair.com/85/ourproducts.htm @exair
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TECHNOLOGY REPORT: Compressed Air 8
www.plantservices.com
Contrary to what some might think,
compressed air is not free. In fact,
for the energy it takes to produce
it to what is generated as a result, it is often
considered the most expensive utility in a
typical manufacturing facility. To add to the
problem, the U.S. DOE notes that more than
50% of all compressed air systems have
energy-efficiency problems. Air compressor
experts have also estimated that as much as
30% of compressed air generated is lost via
leaks in the compressed air system.
Often, when a compressed air system
struggles to meet current demands on the
system, spare compressors are rented and
used as backups or an additional compres-
sor is installed. Both strategies are ex-
pensive, and depending on the size of the
compressors needed, they could equate to
hundreds of thousands of dollars.
Because compressed air systems inherently
have leaks, regardless of piping, use, and
design, implementing a compressed-air leak-
management program can be an economical
and effective way to improve the efficiency
of any compressed air system. Having a
compressed-air leak-management program
in place that is designed to identify and repair
compressed air leaks before they become a
large problem can save time, money, and en-
ergy. Proper planning and creating a sense of
awareness by educating employees on how
costly compressed air leaks can be is integral
to achieving success with any compressed-air
leak-management program.
Compressed air and compressed gas leak
detection remains the most widely used ap-
plication for airborne ultrasound technology.
Employing ultrasound to locate compressed
air and gas leaks and then making the neces-
Something in the air: Ultrasound for compressed-air leak detectionHere’s how to use airborne ultrasound to identify leaks and reap big savings
By Adrian Messer, CMRP, UE Systems
www.plantservices.com
TECHNOLOGY REPORT: Compressed Air 9
sary repairs can have tremendous payback.
Recent advancements in compressed-air
leak detection and reporting allow organiza-
tions to quantify dollars lost and the CFM
loss associated with compressed air leaks.
An effective ultrasonic compressed-air leak
survey will focus on seven key factors: evalua-
tion, detection, identification, tracking, repair,
verification, and re-evaluation. By implement-
ing these steps, a typical manufacturing plant
could reduce its energy waste by roughly 10%
to 20%. As an example, a 1/8” leak at 100 psi
of compressed air at 22 cents per kilowatt
hour has an annual cost of $2,981.
AIRBORNE ULTRASOUND: HOW DOES IT WORK?There are three generic forms of ultrasound
technology: pulse/echo, power, and airborne/
structure-borne. Pulse/echo is the most
recognized form of ultrasound, as this is the
medical form of ultrasound. With power ul-
trasound, as in an ultrasonic cleaner, high-fre-
quency sound waves are emitted. These high-
frequency sound waves have energy, and
they clean parts and various materials. The
form of ultrasound technology that is used
for compressed-air leak detection is airborne
ultrasound. Airborne ultrasound relies on
high-frequency sound waves that are above
the range of normal human hearing. Humans
are able to receive sound within a frequency
range of 20 Hertz (Hz) to 20 kilohertz (kHz),
with the upper threshold of normal human
hearing between 16 kHz and 17 kHz. The ul-
trasonic range begins at 20 kHz. Most ultra-
sound instruments are capable of receiving
or sensing these high-frequency ultrasound
sound waves within a frequency range of 20
kHz to 100 kHz. For ultrasonic leak detection,
an ultrasound instrument that has frequency
tuning capability is recommended, and the
suggested frequency setting is 40 kHz. For
ultrasound instruments that are on a fixed
frequency or where frequency tuning is not a
feature, 38 kHz is usually the frequency set-
ting at which the instrument is fixed.
There are different sources of high-frequen-
cy sound that these ultrasound instruments
detect. For compressed air and compressed
gas leak detection, the source of the ultra-
sound is turbulence.
AIRBORNE ULTRASOUND & COM-PRESSED AIR LEAK DETECTIONOnce an ultrasound instrument that will be
used for compressed air leak detection has
been selected, the planning of the com-
pressed-air survey can begin. One thing to
keep in mind while scanning for compressed-
air leaks out in the facility is the fact that high-
frequency sound is very low-energy. Because
it is low-energy, the sound will not travel
through solid surfaces but rather will bounce
and reflect off of solid surfaces. That’s why it
is important to scan in all directions with the
ultrasound instrument and adjust the instru-
ment’s sensitivity. Adjusting the sensitivity
and scanning in all directions will help pin-
point the location of the compressed air leak.
Once the general area of the compressed air
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TECHNOLOGY REPORT: Compressed Air 10
leak has been located, most ultrasound instru-
ments will come with a focusing probe that
can be slipped over the end of the airborne
scanning module to narrow the field of view
and more precisely identify the leak’s loca-
tion. This method of compressed-air leak
detection using ultrasound is commonly re-
ferred to as the “gross to fine” method.
The logistics of the leak detection route
should now be considered. Performing a
walk-through before the inspection is highly
recommended. The inspector should use this
as an opportunity to determine the specific
zones or areas where compressed air is being
used. Blueprints of the compressed air piping
are also a handy resource when conducting
the initial walk-through. When performing the
initial walk-through, note any safety hazards
and areas where accessibility to the test area
may difficult or may require the use of lad-
ders, extra PPE, or access to locked areas.
Also make note of any obvious signs of com-
pressed air misuse, potential areas of leak-
age, and improper piping installations. Not-
ing any areas of potential leakage or misuse
of compressed air (such as the use of air to
move parts/product, air knives, etc.) will help
eliminate confusion about what the inspector
is finding and help everyone become more
aware of where competing ultrasonic noise
is coming from. Part of the goal of the com-
pressed air leak survey could be to identify
areas where compressed air is being misused
and look for alternatives that could perform
the same function without having to use
costly compressed air.
It’s also necessary to determine the type of
leaks that ultrasound will be used to detect –
for example, pressure leaks in compressed air
or compressed gas systems, vacuum leaks, or
refrigerant leaks. After the initial walk-through,
select one area or zone to test at a time. For
consistency, it is a good practice to begin
at the compressor (or supply) side and then
move to the distribution lines and then to
areas where the compressed air is being used.
As the compressed air leaks are found with
the ultrasound instrument, a tagging system
should be in place for tagging the leak at the
leak site. The tag should have space for record-
ing the leak number, the pressure, the type
of compressed gas, a brief description of the
leak location, and the decibel level of the leak
that was indicated on the ultrasound instru-
ment once the leak location was confirmed. An
estimated cost of the leak may also be helpful
in creating awareness of the expense of com-
pressed air or compressed gas leaks.
When done correctly, an ultrasound compressed-air leak survey can have tremendous
payback in a short period of time.
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TECHNOLOGY REPORT: Compressed Air 11
DOCUMENTATION AND REPORTINGBeyond repairing the compressed-air leaks
that are found during the compressed-air leak
survey, the ultimate success of the survey will
rely largely on the reporting and documenta-
tion of the compressed air leaks. For docu-
mentation purposes, you may want to consid-
er using a leak survey app, which can let the
inspector easily document the compressed
air and compressed gas leaks that are found,
along with the associated cost of the leaks.
When reporting the cost and CFM loss of
compressed air or compressed gas leaks, it’s
important to remember that these are esti-
mated costs. The cost of the compressed air
leaks will be based off of the decibel level
once the leak has been located, the cost per
kilowatt hour of electricity, and the pressure
at the leak site. Ideally, the pressure at the
leak site is best. For example, the compressed
air may start at the compressor at 120 psi, but
where the air is actually being used it may be
regulated down to 75 psi. Look for the near-
est pressure gauge, or if someone from the
plant is available when the leak survey is be-
ing conducted, have someone who is familiar
with the compressed air system. For specialty
gases such as helium, nitrogen, or argon, the
cost of the compressed gas leak is based off
the decibel level reading at the confirmed
leak location, the pressure, and the cost of the
gas as a dollar amount per thousand cubic
feet. When noting the decibel level readings
from the ultrasound instrument, and for the
ultrasonic leak report to be as accurate as
possible, the inspector should note the deci-
bel level readings from the ultrasound instru-
ment approximately 15 inches away from the
confirmed leak location. If the decibel level
readings are taken too close to the leak loca-
tion, the report likely will overestimate the
cost and CFM loss of the leak. Several inde-
pendent studies have compared ultrasound
leak survey reports to actual energy savings,
and they have found that an ultrasound leak
survey is within 20% of the actual savings of
the compressed air leaks. When done cor-
rectly, an ultrasound compressed-air leak sur-
vey can have tremendous payback in a short
period of time – once the leaks have been
repaired, of course.
Compressed air is an expensive utility whose
maintenance and cost is generally taken for
granted. A successful compressed-air leak
survey depends on having the right ultra-
sound instrument for the survey’s needs,
proper training of personnel who will per-
form the survey, planning for how the survey
will be performed by doing an initial walk-
through, documentation of the leaks and the
associated costs, and initiation of repairs once
the leaks have been identified. Through prop-
er documentation and reporting, an ultrasonic
compressed-air leak survey can show tremen-
dous payback and energy savings without a
significant capital expenditure.
Adrian Messer, CMRP, is manager of U.S. operations at
UE Systems (www.uesystems.com). Contact him at
adrianm@uesystems.com.
Digital instrument saves decibelreadings from
the leaks
Create leak reportswith our free software
or mobile app:includes leak rateand cost savings
Ultrasound technologyfinds compressedair leaks quickly
and easily
THE SOLUTION FOR ENERGY SAVING
LEAK DETECTION: Compressed Air & Gases
UE Systems Inc. 14 Hayes St., Elmsford, New York, USA 10523T: +1 914 592 1220 | E: info@uesystems.com | W: www.uesystems.com
UP 3000 & Leak App, the Perfect Pair for Compressed Air
USE THE LEAKSURVEY APP (IOS AND ANDROID)TO CREATE LEAK REPORTS FROM A MOBILE DEVICE
TECHNOLOGY REPORT: Compressed Air 13
www.plantservices.com
During the live Q&A portion of the
webinar, “Examine Key Design Con-
siderations That Contribute to an
Efficient Compressor System,” (now available
on demand at https://plnt.sv/2019-CA), Neil
Mehltretter, engineering manager at Kaeser
Compressors, and Wayne Perry, senior tech-
nical director at Kaeser Compressors, tackled
several attendee questions on common com-
pressed air problems.
PS How can I tell if my compressors are
fighting each other?
NM Usually, you will hear the sound of one
machine loading while the other machine is
turning off and vice versa. You can also see
it in the operating pressure of your system.
The pressure will be low, and then it will go
up. You can also see it in the rapid cycling
that we talked about (in the webinar).
Typically, if you have more than one com-
pressor, and those machines are loaded, you
want to take a look at what that pressure
drop is in your air station. If you turn one
compressor off and widen your pressure
band, you can figure out if only one compres-
sor is needed to operate that system.
WP If you don’t have an air assessment done,
then you don’t have the system instrumented
up. One of the things that I always do is take
a single pressure gauge and check the control
pressures at each compressor that’s in there
to see if they’re fighting each other. Often-
times, the compressor gauge itself or display
is going to be off by a few pounds.
So, take a single gauge and check the pres-
sure at both compressors. Then you can tell
whether the gauges match on the compres-
sors. You can often find that they’re fighting
3 steps to better compressed air system designSpend some time and attention up front to prevent major headaches later
www.plantservices.com
TECHNOLOGY REPORT: Compressed Air 14
each other simply because you thought you
had them set right, and they’re not.
PS What would you say are the most impor-
tant design considerations within a com-
pressor room?
NM It really depends on what the most
important thing for you is. I spent a lot of
time talking about ventilation. For me, what
you have in the room is going to make a
huge difference in getting that heat out.
You’ve already planned where the compres-
sors are going to be. You already know
what the demands are. Ventilation, for me,
would be paramount. But I think Wayne
probably has a different perspective on it.
WP We’ve talked for years and years about
viewing the compressed air system as a
total system, and not as just a group of
components. But if this is a greenfield plant,
then I would take the whole plant as a
system. Look and see if you have the op-
portunity for heat recovery. Locate the
compressor station near that opportunity.
If it’s a food plant, then you always do
clean-in-place. You’re using hot water. Use
water-cooled machines. A100-horsepower
compressor is basically a 75-kilowatt heater.
You might as well use that heat: it’s a BTU to
BTU offset for whatever you’re using to heat
the water. That would be the first thing. Then
ventilation and distribution piping.
Those are the two big areas that I see that
are often neglected. They’ll buy the com-
pressors, the dryers, the filters, and then
neglect to use the right size pipe to get the
air to where they need it. I think that’s really
important in a system design.
PS Are service intervals really necessary?
Can I just have someone visit twice a year?
WP If you only run the compressor for a few
hours a day, you might be able to get
somebody to come twice a year. But yes,
service intervals are critical. Whether it’s a
dry running screw or a lubricated screw,
whether it’s a centrifugal machine or a
piston machine, manufacturers have given
you service intervals to say, “If you service
the machine at these intervals, you’re less
likely to have a failure than if you don’t.” It’s
the unintended failures that cause the
whole plant to go down. So, I would go by
the service intervals and scheduled mainte-
nance around that.
If you have a poorly designed system, then
you have to remember that you’re doing
service intervals based on running hours,
not necessarily loaded hours. You really
want to make that system so the compres-
sors run loaded or they’re off. That way,
you’re maximizing your service dollar by
doing the service on machines that have
actually loaded time and not a lot of un-
loaded time.
Go ahead. Talk data to me.
We’re not shy when it comes to talking dataFor years we’ve led the industry in providing integrated controls.With a suite of sensors for complete package monitoring and the onboard Sigma Control 2™, our compressors’, blowers’, and vacuum packages’ advanced communications capabilities take the guesswork out of connecting with plant controls. If you’re integrating IoT technology, let’s talk.
Visit www.us.kaeser.com/ps to learn more.
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Integrated controls make collecting and communicating data faster
and easier than ever.
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TECHNOLOGY REPORT: Compressed Air 16
The vortex tube has been around
for decades, yet occasionally it is
still misunderstood by engineers
and maintenance personnel, resulting in
improper use with less than ideal results.
This article explains the basic operation of
the vortex tube and guides the user on its
application to generate the best use of its
cooling and heating abilities. The differ-
ence between a successful implementation
and a failed one is the attention is given to
model selection, how the product is ad-
justed for the application, the quality of the
compressed air supply, and the conditions
downstream of the vortex tube.
When selected and applied correctly, suc-
cessful vortex tube applications include
cooling a wide variety of items such as
electronics, gas samples, personnel, cutting
tools and workpieces, molded parts, heat-
sealed products, industrial sewing machine
needles, composite and rubber materials,
thermal sensors, industrial robots and many
more. Although heating applications are not
as prevalent as cooling applications, vortex
tubes are utilized with excellent results for
drying paints and inks, along with shorten-
ing adhesive cure times.
HISTORY OF THE VORTEX TUBEThe effects of the vortex tube were first ob-
served in 1933 by French scientist, George
Ranque, who presented a paper on the
vortex tube in 1933. After that, the vortex
tube disappeared for several years until Ru-
dolf Hilsch revived the study and published
his findings in a 1947 article titled “The Use
of the Expansion of Gases in a Centrifugal
Field as a Cooling Process.”
How much do you know about the vortex tube?Follow these guidelines to get the most heating and cooling out of your vortex tube application
By Steve Broerman, Vortec
www.plantservices.com
TECHNOLOGY REPORT: Compressed Air 17
In 1961 an engineer at General Electric,
Charles Darby Fulton, started a company
in Cincinnati, Ohio, called Fulton Cryogen-
ics. This was the first company to study
the vortex tube in-depth and develop it
for specific industrial applications. In 1968,
Fulton Cryogenics became Vortec Corpo-
ration, which expanded and improved the
vortex tube product line to cover a broad
range of applications in industrial and com-
mercial markets. In 1991, Illinois Tool Works
acquired Vortec, opening access to many
technological methods to study the inner
workings of the vortex tube.
The benefits of vortex tubes, compared to
other cooling methods, include reliability
with no moving parts, small size, instant
adjustable cooling, no RF interference, and
no required maintenance.
AIR MOVEMENT INSIDE THE VORTEX TUBEHigh pressure (compressed) air enters
the inlet and flows into the annular space
surrounding the generator. As it contacts
the generator nozzles, the air loses some
of its pressure, expands and begins to
spin in the generator where it gains near
sonic velocity (see Figure 1). The nozzles
are oriented so that the air is injected
tangentially to the circumference of the
generation chamber. All the air leaves the
generation chamber and goes into the hot
tube.
Centrifugal force keeps the air near the
inside wall of the hot tube as it moves to-
ward the valve at the hot end. By the time
the air reaches the hot end valve, its pres-
sure is less than the nozzle exit pressure
but greater than atmospheric pressure.
The position of the hot end valve deter-
mines how much air leaves at the hot end,
and controls the pressure at the hot end,
before the valve. For hot and cold tem-
perature separation, the valve must allow
only a portion of the air to escape. The
remaining air is forced to the center of the
Figure 1. Basic vortex tube diagram with common names labeling key features
Compressed Air In
Cold Air Out Hot Air Out
Vortex Tube Technology
Control Valve
A vortex tube spins compressed air to produce hot and cold air streams, generating temperatures down to 100F° below inlet temperature.
Vortex Generation Chamber
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TECHNOLOGY REPORT: Compressed Air 18
hot tube, creating a counter-current flow
where, still spinning, circulates back to
the cold outlet. The air travels the entire
length of the hot tube, through the center
of the vortex generation chamber and to
the cold outlet.
The original stream of air in the hot tube did
not occupy the center of the tube because
of the centrifugal force, creating an ideal
path for the inner stream to follow. This,
combined with the pressure mentioned
above, the difference between the hot end
valve and the cold outlet is the reason there
are two distinct spinning air streams, one
spinning inside the other but moving in op-
posite directions.
VORTEX TUBE PERFORMANCEAs the hot end control valve position is
changed, the proportions of hot and cold
air change, but the total flow remains the
same. Therefore, the amount of air exiting
the cold end can vary over a wide range for
a given size vortex tube. The volume of the
cold air is termed “cold fraction.”
A vortex tube design must avoid mixing
the cold inner stream (the cold fraction)
with the warm or hot outer air stream. If
a vortex tube is operating at a high cold
fraction, the chamber through the center
of the generator must be large enough to
handle the cold airflow. If it is not, it will
cause some of the cold air to be deflected
away and mix with the hot air stream, thus
wasting refrigeration. At low cold frac-
tions, the desired result is a small stream
of frigid air. If the generator passage is
too large, it will allow entrainment of some
of the surrounding warm air and raise the
cold outlet temperature.
For any given vortex tube of a fixed total
flow, there is an ideal opening size for all
cold fraction. A vortex tube user will want
one of two modes of operation: either
maximum refrigeration (occurring at about
70% cold fraction) or lowest possible cold
temperature (occurring at about 20% cold
fraction). Maximum refrigeration is required
in almost all applications.
EFFECTS OF INLET TEMPERATUREAs the temperature of the compressed air
increases or decreases, so does the tem-
perature of the cold and hot air streams. If
the compressed air temperature increases
from 70°F in the morning to 80°F in the
afternoon, the cold air temperature will
reflect the 10° F increase during the same
period.
INLET AND OUTLET PRESSURE The cold fraction chart in Figure 2 shows
the cold and hot temperature differentials
achievable at various cold fraction settings
and inlet pressures. The temperature dif-
ferential is related to the absolute pressure
ratio between the inlet air and the cold out-
let. The performance table assumes that the
cold outlet air is at atmospheric pressure.
www.plantservices.com
TECHNOLOGY REPORT: Compressed Air 19
Take, for example, a vortex tube operating
at 90 PSIG (104.7 PSIA) and with the cold
air exhausting to the atmosphere (0 PSIG
or 14.7 PSIA). This results in a pressure drop
ratio of 7.1 to 1 between the inlet and the
outlet. Now, if the inlet pressure remains
the same but the cold airflow is restricted
so that outlet pressure increases to 15 PSIG
(29.7 PSIA), then the pressure drop ratio
falls to (104.7/29.7) 3.5 to 1. Therefore, it is
important not to restrict the flow of cold air
out of the vortex tube by installing under-
sized tubing, fittings, and valves.
As important as it is not to restrict the cold
airflow out of a vortex tube, it is just as impor-
tant not to limit the flow of air into a vortex
tube. The components in the air supply sys-
tem (pipe, hoses, tubing, valves, fittings, and
regulators) must be sized not to restrict the
flow of compressed air, creating an exces-
sive pressure drop. Just one component in
an otherwise properly sized compressed air
system can create excessive pressure drop,
resulting in low air pressure at the vortex tube
inlet. While vortex tubes will create tempera-
ture separation with air pressures as low as 15
PSIG (1 bar), most performance specifications
are stated at 100 PSIG (6.9 bar) air pressure,
measured at the inlet connection.
THE AIR SUPPLY As the saying goes, “garbage in = garbage
out,” and this is true with vortex tubes too.
If dirty, oily, or wet compressed air is sup-
plied to the vortex tube, you will get the
Figure 2. Vortex Tube Cold Fraction Chart
Numbers on White Bar: Temperature Drops | Numbers on Green Bar: Temperature Rises
Cold Fraction 10 20 30 40 50 60 70 80 90
PSIG/BAR F° C° F° C° F° C° F° C° F° C° F° C° F° C° F° C° F° C°
20/1.463 35 62 34 60 33 56 31 51 28 44 24 36 20 28 15 17 9
7 4 15 8 25 14 36 20 50 28 64 36 83 46 107 59 148 82
40/2.891 51 88 49 85 47 80 44 73 41 63 35 52 28 38 21 29 14
9 5 21 11 35 19 52 29 71 39 92 51 117 65 147 82 220 122
60/4.1107 59 104 58 100 56 93 52 84 47 73 41 60 33 45 25 29 16
10 6 24 13 40 22 59 33 80 44 104 58 132 73 168 93 236 131
80/5.5119 66 115 64 110 61 102 57 92 51 80 44 66 36 49 27 31 17
11 7 25 14 43 24 63 35 86 48 113 63 143 79 181 101 249 138
100/6.9127 71 123 68 118 66 110 61 99 55 86 48 71 39 53 29 33 18
12 8 26 114 45 25 67 37 91 51 119 66 151 84 192 107 252 140
120/8.3133 74 129 72 124 69 116 64 104 58 91 50 74 41 55 31 34 19
13 8 27 14 46 26 69 38 94 52 123 68 156 87 195 108 257 142
140/9.7139 78 135 75 129 72 121 67 109 61 94 52 76 42 57 32 35 20
14 8 28 16 47 27 71 36 96 53 124 69 157 88 196 109 259 144
Table Baseline: Compressed Air Temperature: 70°F / 21°C, Pressure Dew Point: -25°F / 32°C, Compressed Air Pressure: 100 psig (6.9 bar)Backpressure: Temperature drops and rises in the chart based on zero (0) backpressure on the hot and cold outlets of the vortex tube. Back pressure exceeding 5 psig (0.3 bar) will reduce the performance of the vortex tube.
www.plantservices.com
TECHNOLOGY REPORT: Compressed Air 20
same quality of air out and, more important-
ly, you will achieve only poor performance.
Over time the contaminants in the air sup-
ply will wear and clog the internal passages,
resulting in decreased cooling performance.
It is crucial to properly filter and dry the
compressed air supply to remove contami-
nants before they reach the vortex tube.
The international standard for compressed
air quality (ISO 8573.1:2001) defines the
compressed air quality that a manufacturer
specifies for their product. There are three
contaminants that the standard classifies:
solid particulate, water vapor, and oil. Up
to six classes define each contaminant. For
example, class 3.4.2 means that (1)10,000
ppm of .5 to 1 micron and 500 ppm of 1 to 5
micron sized solid particulate is allowed per
cubic meter of compressed air; (2) the air
must be dried to a pressure dew point of 37°F
or lower; and (3) there can be no more than
.1 mg per cubic meter of oil vapor in the air.
Compressed air filters and coalescing filters
can satisfy the first and third requirements,
and a refrigerated type drier may be needed
to satisfy the second requirement.
For vortex tubes, cold air guns, and other
cold fraction adjustable vortex tube prod-
ucts where the user may adjust the product
to produce minus 5°F air or less, an ISO
8573.1:2001 air quality Class 3.3.2 is recom-
mended. For fixed cold fraction enclosure
cooling products, an air quality Class 3.4.2 is
recommended.
HUMIDITY EFFECTSA vortex tube does not separate mois-
ture between the hot and the cold air. The
absolute humidity of both the cold and
hot air streams is the same as the enter-
ing compressed air. Moisture will condense,
or freeze, in the cold air if its dew point is
higher than its temperature. Condensation
will not typically occur at moderate cold
air temperatures. However, when tempera-
tures are low enough to cause condensa-
tion, it will appear as “snow.” The snow may
emanate a tacky quality if there is oil vapor
present in the air supply, which can gradu-
ally collect over time, blocking the cold air
passages resulting in product failure.
If water vapor in the compressed air sup-
ply is an issue, the resulting condensation
can be avoided by proper application of a
compressed air dryer. The dryer must be
selected based on the lowest anticipated
cold air temperature. For most enclosure
cooling applications, a refrigerated dryer
with a pressure dew point of 35 to 40°F can
be used. For vortex tube and cold air gun
applications where extreme cold air tem-
peratures may be required, a regenerated
desiccant-type dryer with a pressure dew
point of -40°F may be needed.
Steve Broerman is an Engineer at Vortec (ITW Air Man-
agement) and has spent the last 33 years passionately
developing vortex tube solutions for thousands of diverse
applications. When he is not serving his customers, he
enjoys tooling around in his restored 1972 Triumph TR6.
Vortec was the first company to develop technology for converting the vortex tube phenomenon into practical, effective industrial cooling solutions.
Since then, Vortec has continued to refine and expandvortex tube applications, from cold air guns to enclosurecooler solutions, including multiple hazardous location coolers. coolers. Vortec also manufactures air amplification products for more efficient use of compressed air in blow off, cleaning and conveying applications.
Our products have no moving parts and are backed by a best-in-class 10 year warranty*.*restrictions apply to ProtEX coolers
“With the Vortex enclosure cooler....ourcontrol panels don’t shutdown anymore...that means we don’t lose productiontime.”
PROVIDING PRACTICAL AND EFFICIENTINDUSTRIAL COOLING AND BLOW OFFSOLUTIONS SINCE 1961
INNOVATIVE
...Vortec brought “not only a betterengineered solution, but one that is more cost effective.”
COMPRESSED AIRTECHNOLOGIES
VORTEX TUBES
COLD AIR GUNS
ENCLOSURE COOLERS
ENGINEERED NOZZLES
www.plantservices.com
TECHNOLOGY REPORT: Compressed Air 22
Manhar Grewal graduated from
Purdue University in 2014
with a degree in nuclear engi-
neering and currently serves as product
manager of the IoT and oil-free divisions
at air compressor manufacturer Sullair
(www.sullair.com) in Chicago. He spoke
recently with Plant
Services managing ed-
itor Christine LaFave
Grace about how the
industrial IoT can help
plants better manage
the maintenance and
auditing of their compressed-air systems
– and help newer members of mainte-
nance teams gain a better understanding
of their plant’s compressed-air system
quickly.
PS Nobody wants to connect their com-
pressors – or any other equipment – to the
IoT just for connection’s sake. What are
the on-the-ground benefits plants are
seeking in making the decision to get their
compressed air systems connected to
cloud-based monitoring and management
platforms?
MG Sometimes end users are going after
the real-time monitoring, but most often
they’re after the alerts and notifications.
They want to know if something is going
to happen ahead of time so they can
prevent downtime; they can have planned
maintenance.
Users also can set preventative param-
eters they want to be alerted on, from
the line pressure hitting a certain psi to
Med school for compressor techsHow the IoT and Big Data are helping new engineers and technicians get up to speed
www.plantservices.com
TECHNOLOGY REPORT: Compressed Air 23
the machine’s ambient temperature. IoT
allows users to take a proactive approach
to monitoring their compressor opera-
tions and also plan maintenance, which
improves overall facility operations and
saves time and money.
IoT gives users an opportunity to know
if something is going to happen and the
actions they need to take right now to
fix it. Users also want automated reports
of what part numbers to buy. They want
to know, “OK, I need these parts, and
these are the instructions once I get these
parts,” or they want the contact of whom
to contract to do the work.
PS As with any industry tech trend, there
are leaders, and there are laggards. What
does IoT readiness look like in industry
now versus a few years ago?
MG In the past few years, nobody really
wanted it, and no one was ready for it.
Right now, no one’s still ready for it, but
now everyone wants it yesterday. That’s
just honestly where it’s at right now.
The only bad thing about IoT in general is
it’s great if you’ve got a compressor that’s
IoT-compatible, but it might be one of
200 devices in your end user’s facility. The
main thing that the current IoT solutions
need is the ability to take the data and not
just use the platform, the website inter-
face you have, but also embrace that your
customer probably already has a central
control room that takes all of this data in,
and you need to be able to be compatible
with that.
PS Do you run into questions about the
trustworthiness of alerts and notifications
– skepticism about algorithms’ accuracy
from people who’ve been working with
equipment for 15, 20, 30 years?
MG Yeah, that’s kind of a difficult barrier to
break down, the old-school mentality with
the new mentality. What we’ve tried to do
is make everything super-simple for the
end user. Even if you don’t use our web-
site, if we get you logged in and regis-
tered properly, you’ll get the notifications
you need. If you’re a $5 million factory or
Millennials are all about Big Data. They’d rather just see the data and understand the trends than go to the actual machinery (and) pull
the data off a data logger.
www.plantservices.com
TECHNOLOGY REPORT: Compressed Air 24
you’re a small mom-and-pop shop, you
don’t want a paint booth to go down; you
always want your compressed air system
working.
All of this preventative notification sent
via email or text kind of gives that assur-
ance to the end user. IoT Technology is an
enabler. It’s not a solution to everything,
but it enables all of the solutions you
could ever dream of.
PS When you have conversations with
younger technicians or people newer to
the field, do you see strong interest in
using predictive technologies to help
manage maintenance?
MG Millennials are all about Big Data.
They’d rather just see the data and under-
stand the trends than go to the actual
machinery (and) pull the data off a data
logger. They are very adopting of the type
of technology. They’re more just asking,
“How much data can you give me?”
In the compressed air industry, as with
many industrial jobs, it’s an aging work-
force, and that can present challenges.
When we can show 10 systems and say,
“Hey, user, this is your system, and here’s
an ideal system somebody else is using
that we can implement on you,” that’s
great for demonstrating how to optimize
compressor use.
The main thing that the current IoT solutions need is the ability to embrace that your customer
probably already has a central control room that needs to take all of this data in.
© 2019 Sullair, LLC. All rights reserved.
WHEN OIL FREE AIR IS THE ONLY OPTIONCount on Sullair for reliable oil free compressors that meet your highest standards
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020169_Sullair_Plant Services Compressed Air eBook_7.875x10.5.indd 1020169_Sullair_Plant Services Compressed Air eBook_7.875x10.5.indd 1 3/23/20 12:16 PM3/23/20 12:16 PM
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eHANDBOOK: Compressed Air 26
ADDITIONAL RESOURCES
UNDERSTANDING COMPRESSED AIR SAFETY AND SAVINGSCompressed air safety is a concern within manu-
facturing, mining and processing environments.
Learn about the dangers that can come from
high pressure and noise exposure. Improper use
of compressed air commonly exceeds OSHA’s
noise exposure standards and causes noise
induced hearing loss. Learn how to be sure you are OSHA compliant and
how EXAIR’s Intelligent Compressed Air products can help you. Download
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need for proper heat dissipation has become crucial to keep controls pro-
tected. Tightly packed enclosures and panels restrict airflow, resulting in
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eHANDBOOK: Compressed Air 27
ADDITIONAL RESOURCES
KAESER ENERGY SAVING SYSTEM BASIC COMPRESSED AIR SYSTEM EVALUATIONGiven that energy costs to operate a compressed air
system can total upwards of 70% of overall costs, reduc-
tions in power consumption can have a significant impact
on the bottom line. Studies estimate the energy-saving
potential of many air systems at up to 30 percent. For a
limited time, Kaeser is offering our Kaeser Energy Saving System (KESS) as
a no-cost, no-obligation compressed air system evaluation. Let us help you
estimate air system energy consumption and identify areas for improvement.
Sign up today:us.kaeser.com/KESS
OIL FREE AIR ENSURES RELIABILITY & PRODUCTIVITYMost industrial facilities understand the critical role
their air compressors play in day-to-day operations.
But do you understand the importance of the right air
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THE BASICS OF ELECTRICAL SOUND FILE ANALYSISWhen it comes to monitoring the performance
of electrical machines, ultrasound is one of the best
strategies for detecting faults. But in order to do so,
analysts need to be able to understand .wav files and
the basics of using Spectralyzer software.
Learn more:uesystems.com