Understanding Air Entrainment

EXAIR uses the word entrainment a lot, all of our blowoff products use the principle to amplify the air stream and increase efficiency. But, what is entrainment and what causes the phenomenon? Entrainment can be defined as a fluid that is swept along into an existing moving fluid. This brings Bernoulli’s equation into the picture. When looking at specific situations and conditions Bernoulli’s equation can show some interesting significance with gases.

Bernoulli’s Equation

Bernoulli’s equation takes into account four main variables which are Pressure (P), Density (r), Velocity (v), and a height difference (z); along with a single constant for gravity. you can see the relationship between the velocity squared and the pressure from the equation above.  Being that this relationship is a constant along the streamline; when the velocity increases; the pressure has to come down. Now we have to look at how fluids like to behave. Fluids within a system like to be at a constant pressure when at the same height and reach a state of equilibrium. This means that fluids will always flow towards a low pressure area, which means that if you create a constant low pressure area you can amplify the air stream. This is the same principle as to why airplanes can fly.

EXAIR Super Air Nozzle entrainment

Since compressed air can be an expensive utility, it is good to minimize it and maximize the surrounding entrained air. Therefore we have designed our products to use this entrainment principle to amplify the air blast while using less compressed air and more entrained ambient air. Products like our Super Air Knife can see an amplification ratio (ambient air to compressed air) of up to 40:1; this means for every 1 SCFM of compressed air used we are entraining 40 SCFM of ambient air.

EXAIR’s Super Air Knife

We use this principle for our Air Amplifiers, Air Knifes, Air Nozzles and Jets, Safety Air Guns, and our Gen4 Static Eliminators. Our goal is to save you money and give you better results in the process.  

If you have questions about any of our engineered Intelligent Compressed Air® Products, feel free to contact EXAIR or any Application Engineer.

Cody Biehle
Application Engineer
EXAIR Corporation
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Want to Know How Much Money you can Save? Use EXAIR’s Efficiency Lab

Growing up as a kid of the 80’s I remember wanting a Nintendo 64. This was very much a want due to the excellent advertising and having friends that got them when they first came out. So, like many kids of the times, I set forth to present my case to my parents and sell them on the benefits to me receiving this 64 bit wonder of the world. These benefits all revolved around me doing chores and “helping” to earn money to go towards the end goal. Thinking back now, I really should have started to learn more about negotiating earlier in life because my parents and older brother really made out on the deal. The point is, I had to make sure that they saw a return on their investment. Mainly, I would be entertained and they would get some stuff done around the house without complaints.

1 – NUTS For Nintendo special on ABC news 20/20 from 1988

Well, flash forward to today and I still feel as though it is always an easy justification if I have supporting evidence of the benefits and even better, if there is some form of cost savings that will be had by spending money on a project or a tool. Often times the justification is the amount of time spent on a task. Well, here at EXAIR we completely embrace that justification culture and, in many cases, can provide you the information necessary to present to management or budget committee – the simple ROI your company will see when investing in EXAIR products. The best part is, this study is always free.

The way it works is pretty simple, we want to compare your current solution to our engineered products. EXAIR has a simple form that gets filled out (or you can call, e-mail or chat) explaining your application to us. We ask for a few key pieces of detailed information, and for you to send one of your current solutions (the nozzle, homemade device, or open tube for example). Then we run side by side tests in house to determine air consumption, noise, and force at the same pressure you are using at your facility. That’s right, this testing is all done here at EXAIR through our EXAIR Efficiency Lab. We document these performance characteristics and send a report showing a simple return on investment for you if you replace your device with an EXAIR engineered solution.

EXAIR’s Free Efficiency Lab

This information is then easily backed up by our 30 day guarantee on stock products. Get the EXAIR solution in, test it in your facility and see how the savings stack up. If there is anything that doesn’t stack up, you simply let us know and send the units back.

The entire Efficiency Lab and 30 day guarantee are offered to all of our customers that are within the US and Canada. If you would like to discuss what is possible for you and your team, please reach out to an Application Engineer.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Hertz, Steve – NUTS FOR NINTENDO special on ABC news 20/20 from 1988, 6/24/2010 – Retrieved from https://www.youtube.com/watch?v=yt4KG9ib8S4

When Accessories Become Essentials

In my almost three decades of home ownership, I’ve learned a great deal about maintenance in regard to dwelling structures. Among those lessons are:

  • The importance of the right tool(s) for the job.
  • Having the right materials on hand (I’m looking at you, every plumbing project I’ve ever attempted).
  • When it’s a one-person job, a team effort…or a call to the professionals is always in play.

When it comes to EXAIR Intelligent Compressed Air Products, the first and last concerns above are easily addressed. With precious few exceptions, basic hand tools are all that’s required for installation or maintenance, and they’re engineered & manufactured to be “user friendly”. One key aspect of the “user friendliness” is a comprehensive inventory of accessories.

Some of these accessories are unique to a particular Product Line:

  • Air Knife Plumbing Kits are great, especially for the longer Super Air Knives that need to be plumbed to multiple ports along their length. These consist of air hose and brass fittings (for Aluminum Super Air Knives) or Stainless Steel tubing and fittings (for the Stainless Steel models) that connect in to those multiple ports, allowing for infeed to just one (for Super Air Knives up to 54″ long) or two (for lengths up to 108″) 1/2 NPT fittings. These can actually be used on our Super Ion Air Knives as well.
  • Universal Air Knife Mounting Systems provide for ease of installation, and precise positioning of our Aluminum or Stainless Steel Super, Standard, or Full Flow Air Knives.
  • Coupling Bracket Kits can join Super Air Knives together for a continuous, uninterrupted curtain of air flow in any length that you need. They can also be used if you don’t always need air flow along the entire length of a Super Air Knife assembly. I had the pleasure of assisting a user once who had needed to blow off parts on a hanging conveyor. Some parts were a little under 2ft long; others were about 4ft long. They used the Model 110900 Coupling Bracket Kit to join two Model 110024 24″ Aluminum Super Air Knives together, plumbed them separately, and turned both of them on for the long parts, and just the ‘top’ one for the shorter parts.

Other accessories can be used for a variety of products:

  • Stay Set Hoses (with or without Magnetic Bases) make up instant Blowoff Systems when used with our engineered Air Nozzles. They come in lengths from 6″ to 36″, and can bent by hand to “stay set” (as advertised) to hold their position. They can repositioned, as needed. They’re also popular for use with our 3/4″ and 1-1/4″ Super & Adjustable Air Amplifiers, and can even be used with 3″ Air Knives.
  • Conveyance Hose is a great way to connect point A to point B in a Line Vac Air Operated Conveyor system. Bulk material conveyance really doesn’t get much easier than Line Vac + Hose = Instant Conveyor System (just add compressed air). It can also be used with our Air Amplifiers to duct or route the air flow on the inlet, or the outlet to, or from, one area to another.
  • Mounting Brackets are available for a number of our products:
    • Atomizing Spray Nozzles
    • Line Vacs
    • Filters and Regulators
    • Cabinet Cooler System Thermostats
  • Vacuum Cups are often used with our E-Vac Vacuum Generators for pick-and-place material handling applications. We stock fittings and push-in tubing as well, to complete the package. Those fittings and tubing can also be used for the liquid supply to our Atomizing Spray Nozzles (depending on what you’re spraying, you might want to verify chemical compatibility first; call me if that’s a concern).

Other EXAIR Compressed Air Product Accessories can be used with products that aren’t even ours, or, in conjunction with your compressed air system design for increased efficiency or flexibility:

  • Model 9500-60 60 Gallon Receiver Tanks can be installed near points of high air flow demand to prevent or limit fluctuations in supply throughout the system.
  • Compressed Air Hoses can be made to length, and a variety of Fittings (Hex or Close Nipples, Couplers, Reducers, Tees, Elbows, Crosses, and Bulkhead Fittings) are on the shelf in popular sizes.
  • Our 5 Micron water/dirt Filter Separators are a standard when needing clean, condensate free air to blow through and end-use product.
  • Pressure Regulators are an important factor to minimize compressed air consumption. EXAIR always recommends operating our products at the minimum pressure necessary for a successful application. For example, if using a Super Air Knife to remove dust and light debris, this could be achieved at 20 PSIG, a Pressure Regulator will provide that adjustability and keep the air consumption much lower than if it were operated at 80-100 PSIG.
  • Swivel Fittings, typically used with compressed air nozzles, provide the precision adjustability to focus in on the exact area you need to treat.

If you have any questions about how the above accessories can aid with your application, please relay on our expert team for answers and solutions. Having the right materials and accessories on-hand can simplify installation, enhance performance, save compressed air, and more!

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Air Compressor Motors and Controls, Working Together.

One of the most important aspect of an efficient compressed air delivery system is effective utilization of compressor controls. The proper use of compressor controls is critical to any efficient compressor system operation. In order to reduce operating costs, compressor controls strategies need to be developed starting with minimizing the discharge pressure. This should be set as low as possible to keep energy costs to a minimum.

The compressor system is designed with maximum air demand in mind. During periods of lower demand compressor controls are used to coordinate a reduction in output that matches the demand. There are six primary types of individual compressor controls:

  1. Start/Stop – This is the most basic control. The start/stop function will turn off the motor in response to a pressure signal.
  2. Load/Unload – The motor will run continuously, but the compressor unloads when a set pressure is reached. The compressor will then reload at a specified minimum pressure setting.
  3. Modulating – Restricts the air coming into the compressor to reduce compressor output to a specified minimum. This is also known as throttling or capacity control.
  4. Dual/Auto Dual – On small reciprocating compressors, this control allows the selection of either Start/Stop or Load/Unload.
  5. Variable Displacement – Gradually reduces the compressor displacement without reducing inlet pressure.
  6. Variable Speed – Controls the compressor capacity by adjusting the speed of the electric motor.

All of these controls then control the compressor motors and they have several different starting methods.

There are several types of modern motor starters:

Full Voltage Starters: The original, and simplest method.  These are similar in theory to the old knife switches, but the operator’s hands aren’t right on the connecting switch.  Full line voltage comes in, and amperage can peak at up to 8 times full load (normal operating) amperage during startup.  This can result in voltage dips…not only in the facility itself, but in the neighborhood.  Remember how the lights always dim in those movies when they throw the switch on the electric chair?  It’s kind of like that.

Reduced Voltage Starters: These are electro-mechanical starters.  Full line voltage is reduced, commonly to 50% initially, and steps up, usually in three increments, back to full.  This keeps the current from jumping so drastically during startup, and reduces the stress on mechanical components…like the motor shaft, bearings, and coupling to the compressor.

Solid State (or “Soft”) Starters: Like the Reduced Voltage types, these reduce the full line voltage coming in as well, but instead of increasing incrementally, they gradually and evenly increase the power to bring the motor to full speed over a set period of time.  They also are beneficial because of the reduced stress on mechanical components.

The Application Engineering team at EXAIR Corporation prides ourselves on our expertise of not only point-of-use compressed air application & products, but a good deal of overall system knowledge as well.  If you have questions about your compressed air system, give us a call.

Jordan Shouse
Application Engineer

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Compressor Photo Credits to Bryan Lee, Creative Commons License