Super Air Knife’s Adjustability and Flexibility = Success

The EXAIR Super Air Knife is the most efficient compressed air knife on the market. We know this because we’ve tested them, and our competitors’ offerings, for performance, using the same instruments, controls, and procedures. We’re not going to publish data that we can’t back up, and that’s a fact.

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EXAIR Super Air Knife removing moisture after a rinse on anodized parts.

They’re also ideally suited to a wide variety of applications – they come in lengths from 3 inches to 9 feet long (and can actually be coupled together for uninterrupted air flows of even longer lengths,) a variety of materials for just about any environment. But the best thing about our Super Air Knives is how you can adjust the air pressure and flow to complete a wide variety of tasks. You can adjust them in two different ways, Replacing or adding Shims, or regulating the incoming air pressure.

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Shims for the aluminum, 303 Stainless Steel, and 316 Stainless Steel Super Air Knives

Changing out your shim!

A larger shim gap will give you higher flow and force from your Air Knife. Honestly, the 0.002″ shim that comes pre-installed in all of our Air Knives is perfectly suitable for most blow off applications, and appropriate air supply conditions are the first thing you should check for before going with thicker shims, but if you do indeed need a boost, a thicker shim will indeed give you one…here’s a blog with the video to show you how it’s done:

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Video Blog: How to Change a Shim in a Super Air Knife
Filter Regulator
Regulator and filter

Another advantage to having a Pressure Regulator at every point of use is the flexibility of making pressure adjustments to quickly change to varying production requirements.  Not every application will require a strong blast sometimes a gentle breeze will accomplish the task.  As an example one user of the EXAIR Super Air Knife employs it as an air curtain to prevent product contamination (strong blast) and another to dry different size parts (gentle breeze) coming down their conveyor. For Performance at different supply pressures see the chart below.

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Super Air Knife Performance Table

EXAIR products are highly engineered and are so efficient that they can be operated at lower pressures and still provide exceptional performance!  This save’s you money considering compressed air on the average cost’s .25 cents per 1000 SCFM.

If you’d like to discuss altering the performance of your Super Air Knife, give us a call.

Jordan Shouse
Application Engineer
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Robert Boyle And The Scientific Method

How do we know something is true? In grade school, you may remember being taught a process by which an observation elicits a question, from which a hypothesis can be derived, which leads to a prediction that can be tested, and proven…or not) These steps are commonly known as the Scientific Method, and they’ve been successfully used for thousands of years, by such legendary people of science as Aristotle (384 – 322 BC,) Roger Bacon (1219 – 1292,) Johannes Kepler (1571-1630,) Galileo Galilei (1564-1642) and right up to today’s scientists who run the CERN Large Hadron Collider.  The collider is the largest machine in the world, and its very purpose is the testing and proving (or not) of hypotheses based on questions that come from observations (often made in the LHC itself) in ongoing efforts to answer amazingly complex questions regarding space, time, quantum mechanics, and general relativity.

The Scientific Method is actually the reason (more on this in a minute) for the name of a fundamental law of physics: Boyle’s Law.  It states:

“For a fixed amount of an ideal gas kept at fixed temperature, pressure and volume are inversely proportional.”

And can be mathematically represented:

PV=k, where:

  • P = is the pressure of a gas
  • V = is the volume of that gas, and
  • k = is a constant

So, if “k” is held constant, no matter how pressure changes, volume will change in inverse proportion.  Or, if volume changes, pressure will change in inverse proportion.  In other words, when one goes up, the other goes down.  It’s also quite useful in another formulaic representation, which allows us to calculate the resultant volume (or pressure,) assuming the initial volume & pressure and resultant pressure (or volume) is known:

P1V1=P2V2, where:

  • P1  and P2 are the initial, and resultant, pressures (respectively) and
  • V1  and V2 are the initial, and resultant, volumes (respectively)

This is in fact, what happens when compressed air is generated, so this formula is instrumental in many aspects of air system design, such as determining compressor output, reservoir storage, pneumatic cylinder performance, etc.

Back to the reason it’s called “Boyle’s Law” – it’s not because he discovered this particular phenomenon.  See, in April of 1661, two of Robert Boyle’s contemporaries, Richard Towneley and Henry Power, actually discovered the relationship between the pressure and volume of a gas when they took a barometer up & down a large hill with them.  Richard Towneley discussed his finding with Robert Boyle, who was sufficiently intrigued to perform the formal experiments based on what he called “Mr Towneley’s hypothesis.”  So, for completing the steps of Scientific Method on this phenomenon – going from hypothesis to law –  students, scientists, and engineers remember Robert Boyle.

Russ Bowman
Application Engineer
EXAIR Corporation
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IMGP6394 image courtesy of Matt Buck, Creative Commons License

Types of Air Amplifiers: Amplify Volume or Amplify Pressure

EXAIR Air Amplifiers use a small amount of compressed air to create a tremendous amount of air flow.

As Application Engineers, we help many customers with finding solutions with effective, safe, and efficient EXAIR products.  But, in some instances, we get a request for an air amplifier to increase line pressures.  EXAIR does not manufacture this type of Air Amplifier.  In doing some research on the internet, I was able to find two different types of air amplifiers.  In this blog, I will describe the difference between the pressure-type and volume-type.

The EXAIR Super Air Amplifiers are defined as a volume-type of an amplifier.  They use compressed air to generate a large volume of air flow.  The amplification ratio is the comparison between the inlet air flow and the outlet air flow.  With the EXAIR Super Air Amplifiers, we can reach an amplification ratio of 25 to 1.  They use a Coanda profile with a patented shim to create a low pressure to draw in a large volume of the surrounding air.  EXAIR manufactures a variety of different sizes, materials, and types.  But they all do the same thing, amplify the volume of air.  To give an example, model 120024 Super Air Amplifier has a 25:1 amplification ratio.  It uses 29.2 SCFM (826 SLPM) of compressed air at 80 PSIG (5.5 bar).  So, the outlet air flow is amplified from 29.2 SCFM to 730 SCFM (20,659 SLPM) of air.  This large volume of air works great for cooling, exhausting, and transferring.  But, with any type of amplification, you have to lose something.  With the volume type Air Amplifiers, the outlet pressure is reduced dramatically.

The pressure-type air amplifiers are different from the Super Air Amplifiers as this device will amplify the outlet air pressure, not the volume.  It is an air pump that has a direct dual piston that uses two different diameters.  The larger diameter uses the drive inlet pressure while the smaller diameter is used for the boost pressure.  The amplification ratio is determined by the difference in volume from the drive piston to the boost piston.  They also come in a variety of ranges and sizes.  As an example, an amplification ratio of 15:1 will increase an inlet pressure from 100 PSI (7 bar) to an outlet pressure of 1,500 PSI (103 bar).  Since the pressure-type air amplifier is an air pump, the system has to cycle.  To do this, they use pilot valves to either add the inlet compressed air to the drive piston or to relieve the air pressure from the drive piston.  This cycling portion of the operation does reduce the efficiency of the air amplifier.  The pressure-type air amplifiers are used to generate high pressure for a specific application or area and eliminate the purchase of a high-pressure air compressor.  The applications include air clamps and presses, pressure testing, air brakes, and also blow molding.  Like stated above about losing something with amplifications, the volume of air is reduced dramatically.  Generally, a reservoir tank and over-sizing will be needed for a good system.

The Application Engineers at EXAIR enjoy talking to customers about compressed air applications.  If you need more information about Air Amplifiers, you can contact us directly.  We can explain the volume-type that we manufacture or refer you to a company that makes the pressure-type.  Either way, we will be happy to hear from you.

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

Two Types of Air Amplifiers – Volume and Pressure

When the topic of Air Amplifiers comes up, there are two avenues to consider –  is it the air pressure or the air volume that you wish to amplify?  There exists technologies to amplify either parameter, and we will examine them both.

There may be equipment or processes within a facility that operate best at air pressures higher than can be delivered, due to air compressor limitations or the supply system. An Air Pressure Amplifier can take the existing compressed air supply, and boost the pressure allowing for the higher needed air pressure without requiring a dedicated compressor capable of operating at the higher pressure.

An Air Pressure Amplifier is basically an air pump, driven by a portion of the compressed air supply.  The pump cycles and compresses the remaining amount of compressed air to a higher outlet pressure. This higher output pressure can be used to operate the equipment or process that required the pressure levels that the base system could not supply. The drawback is that the pump system consumes a good amount of the compressed air volume, to power the pump which reduces the amount of air available for other equipment or processes.  This drives up the compressed air consumption for the system, and requires the extra capacity to operate.

The other type of Air Amplifier is the kind that amplifies the air flow volume. EXAIR manufactures this type of amplifier.

AirAmplifiers

The air flow amplification works by taking compressed air (1) and directing into an annular chamber (2). It is then throttled through a small ring nozzle (3) at high velocity. This primary stream of air adheres to the Coanda profile (4) and is directed through the outlet. A low pressure area is created at the center, inducing a high volume flow (5) of surrounding air to be drawn in and added to the main air stream. The combined flow of primary and surrounding air exits as a high volume, high velocity flow.

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EXAIR manufactures (2) types of Air Amplifiers, the Super Air Amplifier and the Adjustable Air Amplifier.  In addition, a special model for High Temperature applications is available.  Sizes range from 3/4″ (19mm) to 8″ (203mm) to meet most air flow requirements.  Air amplification ratios start at 12:1 for the 3/4″ model and increase to 25:1 for the 4″ and 8″ models.

Charts and tables are available to help determine the right Air Amplifier for the job.

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

Brian Bergmann
Application Engineer

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