The Case For The Adjustable E-Vac Vacuum Generator

Vacuum generation is vital to many industrial processes:

*Pick-and-place. Vacuum cup systems are used to move metal sheets onto laser & plasma cutting beds, precisely place parts for assembly using end-of-arm robotic tooling, or moving awkward objects, like plates of glass, by hand.

The same Adjustable E-Vac Vacuum Generator can be used for a range of products, from the cinder bloc (left) to small pavers (right.)

*Bag/package opening.  When plastic bags come off a roll and are fed through an automated filler, vacuum cups can make quick work of opening them up, immediately before the filling operation.

*Vacuum filling.  A closed container can be easily filled, without a pump, by simply drawing a vacuum on it.  Same mechanism (and simplicity) as when you drink a beverage through a straw.

These are just a few of the typical uses for an EXAIR E-Vac Vacuum Generator…I’ve written before about how this is our most versatile product line (by number of different applications) but these in particular are the ones I want to use to make the case for the Adjustable E-Vacs.

EXAIR Adjustable E-Vac Vacuum Generators are available in four distinct models, depending on the needs of your application.  Performance is variable not only by regulating the air supply pressure (like any compressed air product) but also by threading the plug into the body, which changes the size of the annular gap that feeds the Venturi, changing the vacuum and flow levels.  This can be used to overcome vacuum loss due to material porosity or vacuum cup leakage in a pick-and place application, to accommodate different bag sizes or types in an opening application, or to change the rate at which a liquid is moved in a vacuum filling operation.

With four to choose from, EXAIR has an Adjustable E-Vac that will fit your vacuum generating needs.

Because of their larger throat diameter, they’re also better suited for situations where particulates or moisture may be entrained…they won’t clog or ‘stall out’ as is common with other Venturi-type products.  This is especially useful in vacuum chucking/clamping, or when contaminants from dirty environments can make their way into the system.

EXAIR E-Vacs provide instantaneous vacuum response, and are engineered for high efficiency to minimize air consumption.

Like EXAIR In-Line Vacuum Generators, they instantly develop rated vacuum as soon as compressed air is supplied, so they’re well suited for fast moving operations.  With no moving parts, they’re durable, effective, and if you feed them with clean, dry air, they’ll operate a good long time, virtually maintenance free.

If you have a vacuum generating application you’d like to discuss, please give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Person of Interest: Giovanni Battista Venturi

Giovanni Battista Venturi was an Italian physicist that was born in Bibbiano, Italy on March 15, 1746.  He died at the age of 76 on April 24, 1822.  During his early life, Giovanni was ordained as a priest at the age of 23; and, he became a professor of geometry and philosophy at the University of Modena at the age of 28.    He moved to Paris France where he worked with other scholars to expand his knowledge of physics and chemistry.  In 1797, he wrote a dissertation on the now famous “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.

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.

E-Vac design

The EXAIR E-Vac® Vacuum Generators use this phenomenon founded by Giovanni Venturi 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.  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 wear, 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,

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.

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

 

Photo: Venturi Tube with labels by ComputerGeezer an Geof.  GNU Free Documentation License

Custom Solution From Stock For A Pick And Place Application

Even if you’re just a casual, infrequent reader of our blogs, you likely know that EXAIR Corporation is proud of our abilities to customize solutions for “out of the box” compressed air product applications. Oftentimes, this is offered as a custom engineered product, developed from a user’s specifications when one of our stock products just won’t work for one reason or another. For instance, when an exotic material of construction is required for heat or corrosion concerns, a special length or size is needed for space constraints, etc.

An Air Amplifier with a PTFE plug (left,) a curved Super Air Knife (center,) and a flanged Line Vac are just a few ways EXAIR has provided custom solutions.

Other times, though, we can use a stock product for something other than what everyone else uses it for.  We’ve sold Air Amplifiers for use in vacuum chucking, and pick-and-place applications – those are normally the realm of our E-Vac Vacuum Generators.  Speaking of E-Vacs, they’ve been used to deflate basketballs.

And speaking of E-Vacs (still,) I had the pleasure of helping a long-time customer solve a new problem in their growing manufacturing business.  They put their consumer products in blister packages, and recently converted one of the lines that picks & places the plastic “blister” onto the cardboard “backer” from two at a time, to six at a time.  They were using a Model 810003M E-Vac High Vacuum Generator, which worked fine, every time, with two Model 900762 1″ x 1/2″ Oval Vacuum Cups, but when they put four more of those Vacuum Cups on, they weren’t able to pick all six “blisters” every time.

These plastic blisters are smooth and non-porous, so this a “textbook” application for a High Vacuum Generator.  They’re also VERY lightweight, and were picked in a horizontal motion, so the 27″Hg that the Model 810003M can generate wasn’t actually necessary.  By replacing it with a Model 800003M E-Vac Low Vacuum Generator, the extra vacuum flow solved the problem, with no increase in compressed air consumption, which was critical for this area of their operation.

EXAIR E-Vac Vacuum Generators and Vacuum Cups are a reliable, low cost solution for most any pick & place application.

EXAIR Intelligent Compressed Air Products can solve many of your industrial/commercial challenges.  Our catalog documents the ones they’re aimed at.  Others need to be addressed by knowledge and experience…and maybe a little theory to practice.  If that’s the case, call an EXAIR Application Engineer.  We’re here to help, and we’re pretty good at it.