Volunteering Meets Engineering

We’ve shared our experiences of how EXAIR gives each employee the chance to volunteer at an organization they feel close to for an entire workday. This is a great benefit here as we get to see where each person’s interests and passions align and it sometimes gets groups of us out to spend time together doing good for others. While I’ve already used my day for the year by judging my alma maters Senior Design Tech Expo and seeing what the next generation of engineers has to offer, today I have the joy of going even further into the future generations and showcasing some garage engineering of how airflow works.

Today, I am going to be going to a Junior High School, not just any but the one my oldest attends. My best friend and I will be volunteering for their Color Run event which is a fundraiser they put on to end the year. They take a dyed powder and throw it into the air as contestants run around a field and complete various obstacles. At one of the meetings for the event, they were discussing how they went through an excessive amount of dye powder last year. They also mentioned how it didn’t work best as they had filled squeeze bottles that you would see in a restaurant with the powder to disperse as the kids come by. Well, here in Cincinnati it gets to be rather humid this time of year, so dry powder, mixed with humid air, and compression of being squeezed to disperse resulted in lots of clumping and eventually just handfuls of dye powder being dumped on kids. It also doesn’t give the big plume that they want.

1 – The Color Run, Grand Prix Edition (Melbourne 2014)

My friend and I have built a name for ourselves in the PTA as THE DADs. at the meeting, the PTA members looked at my wife who was attending, and asked if she could get THE DADs to show up for this event. Sure enough, there is no better reason to take some time off work than to douse your kid in colored powder, so we were hooked, and then the question came of, can they make this setup better. So the news came to us and we evaluated the old method. The system was simply not adapted to the scale they needed and moisture as well as the fact that some powders brick/cake when compressed wasn’t thought of. So we started brainstorming and our first thought was to take my generator and air compressor from the garage and connect a small Line Vac or even Super Air Amplifier to disperse the powder as we drop it into the entrained airflow. This setup would work, we simply don’t have the time and my generator is so loud the kids would need hearing protection. So then we looked at what we do have. I have a throw bag launcher that was constructed of an old CO2 tank and spring-loaded ball valve to get a weighted bag with a line into trees to help tie off for limb work. That is a single-shot kind of deal though, and we would be like a revolutionary war-fighter on the front line with the kids being the guerilla-like forces that don’t comply with the face-to-face combat style. So that’s out. Next, we laid out what we needed. It’s pretty simple, a large volume of air and a way to put the powder into the airflow.

Well, we both have leaf blowers, they provide a lot of air, but it is a constant flow and you can’t restrict it too much. So what can we do with a large volume of flow? Well, I happen to have a good number of PVC fittings from projects. So a good wye fitting and the leaf blower with continuous flow starts to look like a siphon-fed blow gun.

See the large volume of air will blow across the bottom of the wye fitting which will generate a low pressure on the extra leg of the wye. This gives us a draw of ambient air or in this case, an inlet port for the powder. Then the air and powder mix in the last bit of the discharge tube and voila, a plume of powder in whatever color we have on hand is created! Since I don’t have a good picture of our setup, here’s a video that helps validate our thoughts.

1 – Airbrush Inspired Leaf Blower Ball Shooter

One of the hardest things we had to do is to account for the flow of air being constant since a leaf blower that is powered does not have a quick on-off. This is one of the main benefits of using compressed air in a scenario like this, you can quickly turn it on and off to get rapid movement of air. Blowers tend to take time to spool up, like a gas leaf blower, and they don’t do well with restriction which is why some of these ball launcher designs blow the balls back up the feed tube, restriction of the barrel diameter.

While I didn’t get to use compressed air for this, I still got to use the principles that I have learned through my years here at EXAIR, and I’ll try to tweet out some images of our color plumes when I get a chance so follow my Twitter feed as well, @EXAIR_BF.

Brian Farno
Application Engineer

1 – Chris Phutully from Australia, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons

2 – Keith’s Test Garage, Airbrush Inspired Leav Blower Ball Shooter – retrieved from https://www.youtube.com/watch?v=oz1T70IjG4k

EXAIR Line Vacs™: We can do specials…

Here is a question; what is an eductor?    Eductors are also called ejectors, Venturi jets, aspirators, jet mixers, or jet pumps.  Eductors use either compressed gas or liquid to generate a vacuum by a Venturi effect which is based on Bernoulli’s equation.  (You can read more about the person here, “People of Interest: Giovanni Battista Venturi March 15, 1746 – April 24, 1822 By Tyler Daniel”.)  They can be used for vessel evacuation, gas sampling, pump priming, venting, and blending.  EXAIR Line Vacs work on this same principle in creating a Venturi vacuum by using compressed gas.  In this blog, I will cover the design, verification, and testing that EXAIR provided for a customer’s special.    

For this customer, the design was based around our 2” and 1” 316SS Line Vacs.  They required ISO flanges on the vacuum and exhaust sides to match their piping connections for gas sampling.  They would supply nitrogen to the inlet port as a carrier gas to generate the venturi and to mix with the sample gas.  Since the accuracy of the test is dependent on the amount of each gas, we had to test the operations of the Line Vacs at different conditions. 

First, EXAIR designed these special Line Vacs to get approval.  Once the customer approved, EXAIR had to make a strong effort to meet the other criteria that was requested.  Generally, with our standard Line Vacs, we use our test data with estimated conveyance rates, inlet flow rates, and vacuum pressures measured at 80 PSIG (5.5 bar).  For these special Line Vacs, we had to do a bit more work because it was for gas sampling.  This was not a problem for us.  EXAIR has many calibrated instruments to accurately measure different conditions.  For this customer, we had to measure the inlet flow, suction pressure, velocity, and maximum back pressure at different inlet pressures.  We also had to create another chart showing the exhaust velocities with a back pressure present. 

From these details, the customer could calculate the amount of nitrogen that would be introduced to the gas sample at different pressures and backpressures.  And, as an added preference, they requested us to do a leak check after assembly.  We were willing to buy the flange blanks and add this test procedure to the router.  We looked for leaks between the cap and body of the special Line Vac, as well as the flanges to verify that gas was not escaping.  EXAIR tries to support our customers to the best of our abilities.  For this customer, we worked together to provide the needed information for their setup.    

The reason that I wrote this blog was to show that EXAIR has the capabilities to make special items for specific applications.  If we need to use different materials, design configurations, and even present test data, we can decide the best course of action.  With special products, they are unique to customers in fit, form and function as a solution, whether for end-users or OEMs.  For the special Line Vac above, we presented the data as related to an eductor for this customer’s decision to place the order.  If you would like to see if EXAIR can make a special product for you, please do not hesitate in contacting an Application Engineer at EXAIR.  We will be happy to work with you. 

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb

EXAIR E-Vac Vacuum Generator, How to Pick the Correct One

EXAIR’s compressed air powered E-Vac single stage vacuum generators are a low cost way create vacuum for many operations including- pick and place, clamping, chucking, alignment, lifting, and many others.

The E-Vac provide instantaneous response and are commonly used for pick and place operations.

EXAIR offers the In-Line and Adjustable style of E-Vacs. Both are compact and easy to mount at point of use. With 18 total models available, there is sure to be one that meets any application.  To determine when to use the Adjustable or the In-Line, see this Blog by Russ!

Adjustable E-Vac
In-Line E-Vac







The biggest factor and the first place to start is to determine if the part to be lifted is porous (Example, cardboard) or non-porous (Example, plastic sheet)

  • Porous materials require a low vacuum generator which produces a lower vacuum in exchange for higher vacuum flow which is capable of maintaining a good vacuum level through material that allows air to flow through itself.
  • Non-Porous materials are best suited to use the high vacuum generator which is capable of producing more powerful vacuum for the application.

If you want to see them both in action check this video out! 

E-Vac Video
Click the Video to Watch!

Both the Low Vacuum (for non-porous material) and High Vacuum (for porous material) E-Vacs come in 7 different sizes, ranging from light to very strong vacuum capabilities, to match any application. Special Kits are  available as a way to experiment with an assortment of vacuum cups to determine the best configuration.

EXAIR E-Vac Vacuum Generator

If you have questions about vacuum generation and the E-Vac or any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer

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What is the Venturi Effect?

In 1797 a Italian physicist named Giovanni Battista Venturi wrote a dissertation on the “Venturi Effect”.  However, an actual device was never created or applied until 1888 where Clemens Herschel was awarded the patent for the first Venturi tube.

The Venturi effect is a decrease in fluid pressure when fluid flows through a constricted area of a pipe.  In other words, as the diameter becomes smaller, the fluid velocity becomes faster.  This increase in velocity will create a lower pressure just past the constricted area.  When designed correctly, you can create a strong vacuum or a large negative pressure.

The EXAIR E-Vac® Vacuum Generators use this phenomenon by using compressed air as the fluid.  This type of Venturi tube restricts the internal area to generate a fast velocity through the body creating a vacuum pressure for suction.

EXAIR offers three types of Venturi tubes; low vacuum, high vacuum and adjustable.  Low vacuum units are typically used with porous material because the trade off for low vacuum is higher vacuum flow. The high vacuum generators can create a vacuum level as high as 27” Hg (71 KPa).  The Adjustable E-Vacs can alter the internal air velocities by turning the body and getting different vacuum pressures.  Without any moving parts or electric motors to break, the EXAIR E-Vacs are a simple design that is very durable, effective and long-lasting.  A great product for applications like pick and place, clamping, lifting and vacuum forming.

In-Line E-Vac How It Works
EXAIR E-Vacs provide instantaneous vacuum response, and are engineered for high efficiency to minimize air consumption.

The Venturi effect was discovered in 1797, brought into existence in 1888, and is still used in vacuum applications to this very day.  If you have an application where a Venturi tube could help you, please contact an Application Engineer.  We will be happy to assist you.

Jordan Shouse
Application Engineer
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