COMPRESSED AIR: Tools, Tips, and Best Practices · 2020. 3. 31. · 50% of all compressed air systems have energy-efficiency problems. Air compressor experts have also estimated that

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



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

http://www.exair.com



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.



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.



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.



mailto:[email protected]

mailto:[email protected]

11510 Goldcoast Drive • Cincinnati, Ohio • 45249-1621 • (800) 903-9247 fax: (513) 671-3363 • E-mail: [email protected] • www.exair.com

www.exair.com/85/ourproducts.htm @exair

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MORE SAFETYProviding safe use of compressed air is a top priority engineered into EXAIR products. Eliminate harmful dead end pressures and meet OSHA standards once you have installed EXAIR products.

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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



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



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.



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

[email protected].

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the leaks

Create leak reportswith our free software

or mobile app:includes leak rateand cost savings

Ultrasound technologyfinds compressedair leaks quickly

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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



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.

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http://us.kaeser.com/ps



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



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



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.



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.



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

http://www.vortec.com



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



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.



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

for air quality, purity and performance. We also offer air dryers, filters and other

products to meet your specific air treatment needs.

Learn more at Sullair.com/oilfree

SRL Series DSP Series

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

http://www.sullair.com


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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Learn more:vortec.com

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http://www.exair.com/85/AirSafety_85.htm

https://www.vortec.com/reliable-protection-of-electronics-in-ordinary-and-hazardous-locations


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-

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OIL FREE AIR ENSURES RELIABILITY & PRODUCTIVITYMost industrial facilities understand the critical role

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THE BASICS OF ELECTRICAL SOUND FILE ANALYSISWhen it comes to monitoring the performance

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analysts need to be able to understand .wav files and

the basics of using Spectralyzer software.

Learn more:uesystems.com

https://us.kaeser.com/services/system-design/kaeser-energy-saving-system-kess/free-kess.aspx?utm_source=plantservices&utm_medium=ebook&utm_content=kess&utm_campaign=ps-032020-compressedairtechreport-resource

https://us.kaeser.com/services/system-design/kaeser-energy-saving-system-kess/free-kess.aspx?utm_source=plantservices&utm_medium=ebook&utm_content=kess&utm_campaign=ps-032020-compressedairtechreport-resource

https://america.sullair.com/sites/default/files/2019-08/Sullair_White%20Paper_Oil-Free-Air-Reliability-Productivity.pdf

http://www.uesystems.com/news/the-basics-of-electrical-sound-file-analysis-pt-1

http://www.uesystems.com/news/the-basics-of-electrical-sound-file-analysis-pt-1

Documents

COMPRESSED AIR: Tools, Tips, and Best Practices · 2020. 3. 31. · 50% of all compressed air systems have energy-efficiency problems. Air compressor experts have also estimated that