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!

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Adjustable E-Vac
In-LineE-VacFamily
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.

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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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Vacuum Generator Accessories

In my last blog, I went over How to Choose/Build an E-Vac system, and you can read about that here–  The E-Vac’s are a compressed air powered, single stage vacuum generator, providing a low cost solution for creating a vacuum for many applications. Today, we will look at the many accessories that are available to complete a vacuum system best suited to your vacuum application.

For pick and place operations and hold down or clamping processes, we offer an array of Vacuum Cups. Available from stock are small and large Round, Oval, and Bellows styles. Round cups are best suited for smooth, flat surfaces.  Oval cups provide the most vacuum due to the larger surface area, making them ideal for lifting heavy loads. The Bellows style is best suited for textured or uneven surfaces, where the folds provide a collapsible area that allows the cup to compress and seal to the uneven surface.

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Small and Large Round, Oval and Bellows Vacuum Cups

For vacuum processes where personnel are nearby, there are two (2) types of mufflers available to reduce the sound level to comply with the limits OSHA Standard 29 CFR – 1910.95(a) has established. The EXAIR E-Vac Mufflers are designed so that the E-Vac exhaust is not impeded, so that the highest and fastest vacuum response is achieved. The Standard Muffler (for use with In-Line E-Vacs only) has a closed end and is best suited for vacuum draws that are free from dust and debris.  The Straight Through Muffler is open all the way through and is recommended for those vacuum draws where there will be dirt and debris, since it will not plug up. The Straight Through style offers the best sound level reduction, up to 26 dBA.

E-Vac Mufflers
Standard and Straight Through Mufflers

The vacuum port of the E-Vacs has an NPT threaded connection and with a suitable connector, a vacuum cup can be closely installed, minimizing the system air volume. When vacuum cups are to be remotely mounted, Push-In Connector Type Fittings of assorted styles are available along with the polyurethane tubing to make the installation and vacuum plumbing a cinch.

E-Vac Fittings
Push-In , Swivel Elbow, Swivel Branch Tee, and Bulkhead Connectors

And finally, to get the best performance and maintenance free operation from your E-Vac, always use a source of clean, dry compressed air. We can help you do that with a wide array of Automatic Drain Filter Separators and Oil Removal Filters sized to pair up with the various E-Vac’s. Also available are Pressure Regulators, Vacuum Gauges, Manual Shut Off Valves, Solenoid Valves, and Compressed Air Hose.

If you have questions about E-Vacs and accessories 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.

Brian Bergmann
Application Engineer
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