Bifurcation Of Air – The Wonders of Science That Is The Vortex Tube

EXAIR has provided the benefits of vortex tube technology to the industrial world since 1983. Prior to that, French scientist George Ranque wrote about his discovery in 1928 calling it the tube tourbillion. But it wasn’t until German physicist Rudolf Hilsch’s research paper in 1945 on the wirbelrorhr or whirling tube, that the vortex tube entered the minds of commercial engineers. Nearly 60 years later, EXAIR is a leading provider for cooling products utilizing vortex tube technology.

More than 2,000 BTU/hr in the palm of your hand!

EXAIR Vortex Tubes produce a cold air stream down to -50° F and are a low cost, reliable, maintenance-free (there are no moving parts!) solution to a variety of spot cooling applications. These applications span a wide variety of industries and include cooling of electronic controls, soldered parts, machining operations, heat seals, environmental chambers, and gas samples. We’re always finding compelling new cooling opportunities for the vortex tubes.

How a Vortex Tube Works

So how does it produce the cooling stream? Compressed air is plumbed into the side port of the Vortex Tube where it is ejected tangentially into the internal chamber where the generator is located. The air begins flowing around the generator and spinning up to 1 million RPM toward the hot end (right side in the animation above) of the tube, where some hot air escapes through a control valve. Still spinning, the remaining air is forced back through the middle of the outer vortex. Through a process of conservation of angular momentum, the inner stream loses some kinetic energy in the form of HEAT to the outer stream and exits the vortex tube as COLD air on the other side.

The adjustable control valve adjusts what’s known as the cold fraction. Opening the valve reduces the cold air temperature and also the cold airflow volume. One can achieve the maximum refrigeration (an optimum combination of temperature and volume of flow) around an 80% cold fraction. EXAIR publishes performance charts in our catalog and online to help you dial into the right setting for your application, and you can always contact a real, live, Application Engineer to walk you through it.

EXAIR manufactures its vortex tubes of stainless steel for resistance to corrosion and oxidation. They come in small, medium and large sizes that consume from 2 to 150 SCFM and offer from 135 to 10,200 BTU/hr cooling capacity. Each size can generate several different flow rates, dictated by a small but key part called the generator. That generator can be changed out to increase or decrease the flow rate.

While operation and setup of an EXAIR Vortex Tube are easy, its performance will begin to  decrease with back pressure on the cold or hot air exhaust of over 3 PSIG. This is a key  when delivering the cold or hot airflow through tubes or pipes. They must be sized to minimize or eliminate back pressure.

The Vortex Tube is integrated into a variety of EXAIR products for specific applications, like the Adjustable Spot Cooler, the Mini Cooler, the Cold Gun Aircoolant System and our family of Cabinet Cooler Systems.

If you would like to discuss your next cooling application, please contact an Application Engineer directly and let our team lead you to the most efficient solution on the market.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

FullStream Liquid Atomizing Nozzles

At EXAIR, we know compressed air, and we’ve been helping customers around the world get the most out of their compressed air systems since 1983. It was only logical that, about ten years ago, we got into using compressed air for liquid atomization.  If you’re looking to spray a liquid in a fine mist with a controllable pattern & flow rate, there are many advantages to using compressed air to atomize it:

  • Adjustability
  • Maximum dispersion
  • Optimal, efficient consumption
  • Small droplet size

Since their introduction, EXAIR has come to offer 142 distinct models of Air Atomizing Spray Nozzles, and, along the way, we leveraged our engineering, machining, and manufacturing prowess to gain position as an industry leader in liquid spraying.  So much so, that, earlier this year, we introduced a spraying product line that doesn’t require compressed air:  the FullStream Cone Liquid Atomizing Nozzles.  Instead of using the energy of compressed air to effect atomization, these use the energy of the liquid’s pressure and flow to change the continuous stream of liquid flow entering the nozzle into a conical spray as it exits to atmospheric pressure.  Here’s how it works:

While Air Atomizing Spray Nozzles maintain their advantage of a smaller droplet size (ours consistently make droplets under 100 microns in size,) there are clear benefits in certain applications to the FullStream Cone Liquid Atomizing Nozzles:

  • Higher liquid flow rates
  • Increased liquid coverage
  • More compact design

These are all important in applications like quenching, cooling, foam breaking, lubricating, degreasing, and sanitizing.  All stainless steel construction means they’ll stand up to a variety of chemicals…both in what’s being sprayed, and in the environment in which they’re installed.

If you have a liquid that needs sprayed, EXAIR has an engineered solution.  Call an EXAIR Application Engineer today to find out more.

Russ Bowman
Application Engineer
EXAIR Corporation
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Compressed Air and Pneumatic Systems

Compressed Air Pipe

Compressed air is used to operate pneumatic systems in a facility, and it can be segregated into three main sections; the supply side, the demand side, and the distribution system.  The supply side is the air compressor, after-cooler, dryer, and receiver tank that produce and treat the compressed air.  They are generally found in a compressor room.  The demand side is a collection of devices that will use the compressed air to do “work”.  These pneumatic components are generally scattered throughout the facility.  To connect the supply side to the demand side, a distribution system is required.  Distribution systems are pipes or tubes which carry compressed air from the air compressor to the pneumatic devices.  The three sections have to work together to make an effective and efficient system.

Compressed air is a clean utility that is used in many different ways, and it is much safer than electrical or hydraulic systems.  But most people think that compressed air is free, and it is most certainly not.  Because of the cost, compressed air is considered to be a fourth utility in manufacturing plants.  For an electrical motor to reduce a volume of air by compressing it, it takes roughly 1 horsepower (746 watts) to compress 4 cubic feet (113L) of air every minute to 125 PSI (8.5 bar).  With almost every manufacturing plant in the world utilizing air compressors larger than 1 horsepower, the amount of energy needed is extraordinary.

Let’s determine the energy cost to operate an air compressor by Equation 1:

Equation 1:

Cost = hp * 0.746 * hours * rate / (motor efficiency)

where:

Cost – US$

hp – horsepower of motor

0.746 – conversion KW/hp

hours – running time

rate – cost for electricity, US$/KWh

motor efficiency – average for an electric motor is 95%.

As an example, a manufacturing plant operates a 100 HP air compressor in their facility.  The cycle time for the air compressor is roughly 60%.  To calculate the hours of running time per year, I used 250 days/year at 16 hours/day.  So operating hours equal 250 * 16 * 0.60 = 2,400 hours per year.  The electrical rate for this facility is $0.10/KWh. With these factors, the annual cost to run the air compressor can be calculated by Equation 1:

Cost = 100hp * 0.746 KW/hp * 2,400hr * $0.10/KWh / 0.95 = $18,846 per year in electrical costs.

Filters and Regulator

If we look at the point-of-use or demand side, the compressed air is generally conditioned to be used to run and control the pneumatic system.  The basic units include filters, regulators, and lubricators.  The filters are used to remove any oil, water, vapor, and pipe scale to keep your pneumatic system clean.  They fall into different types and categories depending on the cleanliness level required.

Filter Separators are more of a coarse filtration which will capture liquid water, oil, and particulate.  The Oil Removal Filters are more of a fine filtration which can capture particles down to 0.03 micron.  They are also designed to “coalesce” the small liquid particles into larger droplets for gravity removal.  One other group is for removing oil vapor and smell.  This type of filter uses activated charcoal to adsorb the vapor for food and pharmaceutical industries.  Filters should be placed upstream of regulators.

Pressure Regulators change the pressure downstream for safety and control.  Pneumatic devices need both flow and pressure to work correctly.  The lubricator, which is placed after the Regulator, helps to add clean oil in a compressed air line.  Air tools, cylinders, and valves use the oil to keep seals from wearing with dynamic functions.  Once the compressed air is “ready” for use, then it is ready to do many applications.

For EXAIR, we manufacture products that use the compressed air safely, efficiently, and effectively.  EXAIR likes to use the 5-C’s; Coat, Clean, Cool, Convey and Conserve.  We have products that can do each part with 16 different product lines.  EXAIR has been manufacturing Intelligent Compressed Air Products since 1983.  Compressed air is an expensive system to operate pneumatic systems; but, with EXAIR products, you can save yourself much money.  If you need alternative ways to decrease electrical cost, improve safety, and increase productivity when using compressed air, an Application Engineer at EXAIR will be happy to help you.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

EXAIR Atomizing Spray Nozzles for Coating, Cleaning, Cooling

A recent customer in the automation / tool making industry had a need to spray a mold release agent onto some specialized tooling. Originally, the customer had planned to use some sort of pressurized sprayer. After some initial tests to prove the concept, the customer found that the moving mechanical parts of the sprayer became fouled by the release agent. And cleaning the internal parts was not easy to do.

No Drip Atomizing Nozzle
No Drip Atomizing Nozzle

In their search for a more permanent solution, the customer came across EXAIR Atomizing Nozzles. After going through some application type questions to narrow the focus down to one model, we determined that the customer would be best served by model AF1010SS (Internal Mix, Flat Fan Pattern Atomizing Nozzle). The customer had a couple of questions about the nozzle in order test the product.

  1. Is it possible to disassemble the nozzle and clean it completely? The answer is yes, the Atomizing Nozzles can be completely disassembled to allow for cleaning, maintenance or replacement of worn parts.
  2. Are the nozzles solvent resistant? The answer is also yes; the Atomizing Nozzles are made of AISI303 type stainless steel and can be cleaned with any normal solvent based cleaner.

Earlier in this article, I mentioned that we went through some application type questions. Here is a list of general questions that we normally ask a customer about their application in order to determine which in our selection would be best suited.

  1. What is the volume of liquid flow (G/Hr) needed for the application?
  2. What is the viscosity (cP) of the liquid being applied?
  3. What are the required spray pattern, size and shape required?
  4. Is the liquid under pressure (by pump or pressure pot)? If so, what is the liquid pressure?
    1. Side note: we have options for non-pressurized liquid by using our siphon fed nozzles.

If you have an application where you have a liquid that needs to be applied in atomized form to a target, or perhaps a humidification application, please give EXAIR Atomizing Nozzles your consideration.

Jordan Shouse
Application Engineer

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