Tag: air jet

Henri Coanda and his Effect on Compressed Air

Published on by EricKuhnash@EXAIR.comLeave a comment

Henri defined the Coanda Effect – the tendency of a jet of fluid emerging from an orifice to follow an adjacent flat or curved surface and to entrain fluid from the surroundings so that a region of lower pressure develops.

Compressed air flows through the inlet (1) to the Full Flow (left) or Standard (right) Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.

Henri-Marie Coanda (1885-1972) discovered the Coanda Effect in1930. He observed that a stream of air (fluid) emerging from a nozzle tends to follow a nearby curved surface, if the curvature of the surface or angle the surface makes with the stream is not too sharp. For example, if a stream of fluid is flowing along a solid surface which is curved slightly from the stream, the fluid will tend to follow the surface.

A number EXAIR products are designed to utilize the Coanda Effect and aid their performance. In some products, the Coanda Effect aids to create an amplification area where additional ambient air is drawn into the total airflow to increase total volume of air upon a target. This creates a more efficient and effective product. Also, since not as much compressed air is required, the noise levels decrease for products like EXAIR’s air knives, air nozzles, air jets and air amplifiers. EXAIR has been successful with positive impact for compressed air energy savings and noise reductions helping us meet or exceed OSHA Standard 29 CFR-1910.95 9(a) Maximum Allowable Noise Exposure.

Please contact EXAIR with regards to our Intelligent Compressed Air Products. We can help you with your next cooling, blow-off, drying or any compressed air needs.

Eric Kuhnash
Application Engineer
Email: erickuhnash@exair.com
Twitter: @EXAIR_EK

1- Spoon Coanda image- https://creativecommons.org/licenses/by-sa/2.5/deed.en

Great Stuff About Jets

Published on by Russ BowmanLeave a comment

There are a number of fascinating facts about jets…both the aircraft engines and the EXAIR Intelligent Compressed Air Products:

  • Because they don’t require dense air to engage spinning blades (like their propeller driven counterparts,) they can operate at much higher altitudes. (Jet aircraft engines only)
  • They provide a high thrust, directed airstream, which makes them great for part ejection, chip removal, and part drying. (EXAIR Air Jets only)
  • With few or no moving parts, they are extremely reliable, durable, and safe. (Both jet aircraft engines and EXAIR Air Jets)
  • They use the Coanda effect (a principle of fluidics whereby a fluid flow tends to attach itself to a nearby surface, and follow that surface regardless of the flow’s initial direction) to do what they do.
    • EXAIR Air Jets use this principle to generate a vacuum in their throat, pulling in a large amount of “free” air from the surround environment, making their use of compressed air very, very efficient.
    • Jet (and propeller driven) aircraft wings employ the Coanda effect to create aerodynamic lift, enabling the plane to fly.

Now, since I’m not a pilot, nor do I particularly like to fly, but I AM a fluid dynamics nerd, the rest of this blog will be about the Air Jets that EXAIR makes.

All of our Air Jet products operate on the same principle…using the Coanda effect (as described above) to generate a high volume air flow while minimizing compressed air consumption:

(1) Compressed air enters and is distributed through an annular ring, and directed towards the discharge via the Coanda effect.
(2) This causes entrainment of surrounding air, both through the throat, and at the discharge.
(3) The total developed flow has tremendous force and velocity, for a minimal consumption of valuable compressed air.(1) Compressed air enters and is distributed through an annular ring, and directed towards the discharge via the Coanda effect.
(2) This causes entrainment of surrounding air, both through the throat, and at the discharge.
(3) The total developed flow has tremendous force and velocity, for a minimal consumption of valuable compressed air.

There are four distinct models of the EXAIR Air Jet:

  • Model 6013 High Velocity Air Jet is made of brass for economy and durability.  The annular ring gap (see 1, above) is fixed by a 0.015″ thick shim.  Performance can be modified by changing to a 0.006″ or 0.009″ thick shim, which come in the Model 6313 Shim Set.
  • Model 6013SS is a Type 303 Stainless Steel version, for higher temperatures – good to 400°F (204°C) – and superior corrosion resistance.
  • Model 6019 Adjustable Air Jet is brass construction, and dimensionally identical to the Model 6103.  Instead of a shim that sets the annular ring gap, though, it has a threaded plug, with a micrometer-style indicator, to “fine tune” the gap.
  • Model 6019SS is the Type 303 Stainless Steel version…fine tuning adjustability, good for high heat and/or corrosive elements.

Four distinct models to meet the needs of your air blowing application.

If you’d like to find out more about EXAIR’s quiet, efficient, and safe Air Jets, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Engineered Air Nozzles and Jets Outperform – Save Air, Increase Safety, Save Money

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EXAIR’s Engineered Air Nozzles and Air Jets provide a simple solution to lower compressed air usage and reduce noise levels for compressed air blowoff operations.

Why Air Nozzles and Jets – When compared to commonly used open copper tubes or pipes, compressed air savings can be as high as 80%. And with less compressed air, sound levels are greatly reduced.  A 10 dBA noise level reduction is typical.  All EXAIR Air Nozzles and Jets meet the Occupational Safety and Health Administration (OSHA) maximum dead end pressure and sound level exposure requirements. They also carry the CE mark.

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The largest selection of engineered Air Nozzle sizes and materials are only available form EXAIR 

EXAIR Nozzles are engineered to take advantage of the Coanda effect to amplify the airflow up to 25 times or more. Compressed air is ejected through the small orifices and surrounding air is entrained into the main stream. The resulting air stream is a high volume, high velocity blast of air at minimal consumption.  EXAIR manufactures many styles, from the very small, but powerful Atto Super Air Nozzles, to the largest 1-1/4 NPT Super Air Nozzle.  Also offered are 1″ and 2″ wide Flat Super Air Nozzles, and the Back Blow style for cleaning out tubes, pipes, channels or holes from 1/4″ to 16″ in diameter.
EXAIR Air Jets utilize the Coanda effect (wall attachment of a high velocity fluid) to produce air motion in their surroundings.  A small amount of compressed air (1) is throttled through an internal ring nozzle above sonic velocity.  A vacuum is produced, pulling in large volumes of surrounding, or ‘free’ air, through an around the jet (2).  The exit flow is the combination of the two air sources (3).

air-jet
How an Air Jet Works

EXAIR manufactures Air Jets in two types, High Velocity, and Adjustable with materials of construction of brass and Type 303 Stainless Steel.  The High Velocity Air Jet uses a changeable shim to set the gap, controlling the force and flow of the air.  The Adjustable does not use a shim, and has a micrometer gap indicator and locking ring to allow for varying force and flow performance.

AirJetFamily
EXAIR Air Jets – High Velocity type on the left, Adjustable type on the Right

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

Brian Bergmann
Application Engineer

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Getting A Little More Vacuum and Flow

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Last week, a customer called and indicated that he was a long time user of the model 6013 High Velocity Air Jet.

6013
Model 6013 High Velocity Air Jet

The customer was using the Air Jet to remove light trim scrap from a manufacturing process. The Air Jets utilize the Coanda effect (wall attachment of a high velocity fluid) to produce air motion in their surroundings.  A small amount of compressed air to the Air Jet is throttled through an internal ring nozzle at speeds above sonic velocity.  In the above image, this produces a vacuum at the left side, pulling in large volumes of surrounding air. By utilizing this vacuum pull and ducting the right side exhaust, air and scrap stream to a collection area. The customer assembled a small, efficient, and inexpensive scrap removal system.

The reason the customer had called in was there were some recent changes to the manufacturing process and needed a bit more vacuum force and flow to handle larger scrap and longer travel. We explored using a larger shim, but they were already using the largest size (0.015″.) We talked about the other products that EXAIR offers (Air Amplifiers, Line Vacs) that are used for scrap removal and conveyance.  But with any change, there are usually other modifications and approvals that must be dealt with in order to proceed. So we hit upon the Adjustable Air Jet, which is an adjustable version of the model 6013.

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Model 6019 Adjustable Air Jet

The model 6019 Adjustable Air Jet utilizes an adjustable air gap in place of the fixed shim thickness.  This allows for greater air flow, which results in greater vacuum and conveyance distances. As is the case for many customers, we gathered some additional data to help this customer make a decision. We set up each of the units and tested them at maximum capabilities, and the model 6019 was shown to deliver upwards of 50% greater flow.  The customer felt certain this level of performance would handle what the changed process would require, and best of all, no modifications to any part of the set-up would be required, simply install the 6019 where the 6013 was currently placed.

The High Velocity Air Jet is also part of the model 1909 Blowoff Kit, and is also used in the model 8193 Ion Air Gun and model 8194 Ion Air Jet, for Static Elimination applications. Of course, each can be purchased as an individual item.

To discuss your application and how an EXAIR Intelligent Compressed Air Product can make your process better, feel free to contact EXAIR and myself or one of our other Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

Send me an email
Find us on the Web
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Twitter: @EXAIR_BB