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

High Vacuum (Non-porous) and Low Vacuum (Porous) E-Vacs: Vacuum Generator Overview

In-Line E-Vac

With the amount of energy in compressed air, EXAIR can manipulate it by design for a variety of applications. One way that we can do this is by creating a vacuum pressure by the Venturi effect. By increasing the velocity of air through a constricted area, a low pressure, or vacuum, is created. Unlike a mechanical vacuum pump, the E-Vac does not have any moving parts or motors to wear. This maintenance free device uses only compressed air to generate a powerful vacuum pressure in a very compact and lightweight design. They can create vacuum levels up to 27” Hg (91 kPa) where complete vacuum is at 29.92” Hg (101.4 kPa). With our single stage systems, we can generate different vacuum levels and flows to create the optimal vacuum generation for your application.

Have you ever placed your hand over the hose of a vacuum? You can feel the maximum amount of vacuum pressure on your hand. The maximum vacuum pressure value is only at the condition of zero air flow. When you remove your hand from the hose, you change the vacuum pressure to a much lower value, but now you have the maximum amount of air flow. Like the E-Vacs, EXAIR has designed the product to either give you the maximum vacuum pressure or the maximum vacuum air flow. EXAIR separates these two vacuum generators as High Vacuum and Low Vacuum.

The high vacuum style is designed for non-porous products like glass, marble, and steel sheets. The low vacuum style is for porous products like cardboard, fabric, and plywood. Both types of vacuum generators are commonly used to pick and place parts, open bags, evacuate molds, and vacuum forming. They are easily adjusted by a regulator and a solenoid valve making the E-Vac very versatile. Even with no moving parts, these vacuum generators are quick to respond with very long cycle rates. The inline design makes them easy to install, so, you can begin using this vacuum product without much setup time. With the single stage design, it eliminates any vacuum fluctuation. I will go through both types of E-Vacs to explain the advantages in using these kinds of vacuum generators for different applications.

The High Vacuum Generator is used for non-porous products in pick and place applications as well as vacuum forming, clamping, and evacuation. This type of generator can create a vacuum pressure up to 27” Hg (91 kPa). In conjunction with the EXAIR vacuum cups, it allows for maximum holding capacity for heavy materials. We offer 7 different sizes ranging from 2 SCFM (65 SLPM) to 31 SCFM (872 SLPM) at 80 PSIG (5.5 Bar). They can be matched to the size and quantity of vacuum cups for increased efficiency as well as for improved cycle rates. If the surface of a rigid sheet is smooth or the application requires a high vacuum pressure, the High Vacuum E-Vac Generator would be the best product to use.

The Low Vacuum Generator is used for porous products as well as more delicate surfaces. This generator has a maximum vacuum pressure of 21” Hg (71 kPa). The design is such to allow for maximum air flow to make up any losses through the material or sealing area. With a regulator, you can control the maximum vacuum level to eliminate dimpling or disfiguring of the surface. Even with fabrics and rough surfaces, the Low Vacuum Generator can still pick up and hold the material. We offer 7 different sizes ranging from 1.5 SCFM (42.5 SLPM) to 17 SCFM (476 SLPM) at 80 PSIG (5.5 Bar). They can also be matched to the size and quantity of vacuum cups as well as to overcome any leakage. If the surface of the product being moved is rough or the surface is very delicate, the Low Vacuum E-Vac Generator would be the best product to use.

EXAIR created a video to show the difference between the E-Vacs as well as a demonstration.

Click Video

For experimentation with the E-Vacs and the vacuum cups, EXAIR offers kits for both types of generators. The standard kit includes four pairs of vacuum cups (matched to the size of the E-Vac), 10 feet (3 m) of poly line, and an assortment of fittings. For the Deluxe kit, it will include the same items in the standard kit, plus an automatic drain filter and a regulator. The E-Vacs are made of a durable 6061 aluminum, but if a different material is required for your application, EXAIR can review this request.

The EXAIR E-Vac offers an efficient, simple, and maintenance free solution to create vacuum. Whether lifting product horizontally or vertically, opening bags, aligning sheets or leak checking, the E-Vac ensures a flexible and reliable way to continuously keep your operation moving. As compared to an electric vacuum pump, these vacuum generators are much smaller, less expensive and much quieter. If you need help in sizing and selecting the correct model, you can contact an Application Engineer at EXAIR.

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

Change Your Vacuum System at a Moments Notice

In my video from two weeks ago, I showed the operation and adjustment of the adjustable vacuum generator.  The video was short and simple for the viewer, but during the brainstorming of the video, I thought of a variety of topics I would like to cover.  Today, I thought I would expound on some of the ideas and benefits of why you would adjust the vacuum level on a vacuum generator.


As Russ mentioned in his blog this week, there are a variety of uses for vacuum generators.  The “textbook” application for vacuum generators is in conjunction with vacuum cups for pick and place applications.  For this application, you typically want to use a vacuum generator that is designed for the material that you are lifting.  For instance, a porous vacuum generator should be used when lifting  cardboard, fabric, paper, or foam (materials that let air flow through).  If you’re lifting metal, solid plastic, wax covered cardboard, or anything else that will stop the flow of air and have a smooth surface, a non-porous vacuum generator should be used.  You can use a porous generator on a non-porous surface, but you will be using more compressed air than you would use with a non-porous generator.

Now that we know when to use a non-porous generator and a porous generator what do you do if you production line or warehouse is changing the products it is moving.  Say that you want to be able to lift stainless steel products in the morning, but in the afternoon you are looking to lift the cardboard boxes containing the (now packaged) product.  The adjustable vacuum generator is much more efficient to adjust than changing all of the vacuum generators or having a different lifting rig for each application.

Alternatively, if you are using a vacuum generator to draw a vacuum on a vessel and that vacuum needs to be specifically controlled.  Say the material can’t withstand a vacuum above 10 inches of mercury or you need to reach a minimum vacuum level in .5 seconds to evacuate a vessel.  The Adjustable E-vac will allow you to use the minimum amount of compressed air to get the job done.

Dave Woerner
Application Engineer

Manufactured with This in Mind – Used For This, That & the Other

One thing that makes being an Application Engineer so interesting is the variety of uses for certain products in our catalog. They all seem to have a few “textbook” applications, but some can be used across a wide range of industries to perform drastically different tasks.

Take, for instance, the E-Vac Vacuum Generators. The “textbook” application is pick-and-place…a Vacuum Cup is hooked up to an E-Vac, and used to securely pick up an object and move it from one place to another. Depending on the geometry, surface texture, and weight of the object, we have different E-Vacs, Vacuum Cups, fittings and tubing/hose to build the appropriate lifting system.

Then, there are the not-so-typical applications. I wrote a while back about a customer who uses one to deflate sports balls. They’re also handy for placing labels, evacuating molds, vacuum forming, liquid sampling…all kinds of applications where they can easily, quickly, and efficiently do the job of very expensive and complex pump-based vacuum systems. And with no moving parts, they’re virtually maintenance-free…another big advantage over vacuum pump systems.

If your application requires generating a vacuum, an EXAIR E-Vac is certainly worth consideration. With 32 models to choose from, odds are, we’ve got what you’re looking for.

Russ Bowman
Application Engineer
EXAIR Corporation
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