We Lift Things Up and Put Them Down (Part 2): EXAIR’s E-Vac Vacuum Generators

A few months ago, I wrote here on the EXAIR Blog about my wife and I competing in our very first powerlifting competition. It’s a long and tiring process training for months for one single day, but to see all of your hard work payoff on the platform come competition day makes it all worth it. After competing on Saturday, we were both back in the gym the following Monday morning getting ready for the next one. Memorial Day weekend we participated in the Rivercity Barbell MAYhem meet in Northern Kentucky, another trophy for my wife, and another 2nd place medal for me. I’m beginning to see a trend here…. The entire day didn’t go the way I wanted it to, but I was pleased with a strong finish: a 500lb deadlift on my 3rd attempt to end the day. Exactly what I had in mind on the drive home in early January after our first meet.

After a full, long day of lifting stuff up and putting it back down, I was definitely ready to hit the bed right upon getting home. I could’ve saved myself quite a bit of energy and exhaustion by using one of EXAIR’s E-Vac Vacuum Generators. Although I’m fairly certain that would end in a quick disqualification…  

EXAIR’s E-Vacs are designed to take the difficult part out of lifting, placing, clamping, and mounting across a wide variety of parts and materials. EXAIR offers two primary styles of E-Vacs to serve your needs: In-Line E-Vacs & our Adjustable E-Vacs

The In-Line E-Vacs are a single stage, cylindrical units that are compact and easy to mount right at the point of use. They can be held in place by threading directly onto a compressed air line, or by the use of a mounting clip. We offer styles for use with porous materials, such as paper or cardboard, with vacuum levels up to 21” Hg and vacuum flows up to 18.5 SCFM. For non-porous materials, such as glass, we offer units with vacuum levels up to 27” Hg and with vacuum flows up to 15.8 SCFM.

Adjustable E-Vac

For applications that may have varying weights and sizes, we offer a line of Adjustable E-Vacs as well. With the simple loosening of a locknut and turning the exhaust, you can increase and decrease both the level of vacuum and the vacuum flow. This style is also an excellent choice for applications where large particulate may be present and can pass through the vacuum. We offer (4) different models with adjustable vacuum up to 25” Hg and vacuum flows up to 81 SCFM.

No matter what it is you’re trying to pick up, EXAIR has an E-Vac suited to the task. For help in sizing the appropriate vacuum generator for your application, feel free to give us a call. Hopefully by then I’ve figured out how to win one of these competitions, and I’m sure I’ll have a trophy case full of ‘em for my wife.

Tyler Daniel

Application Engineer

E-mail: TylerDaniel@EXAIR.com

Twitter: @EXAIR_TD

Additional Benefits To The Adjustable E-Vac Vacuum Generators

The EXAIR Adjustable E-Vacs are available in 4 different sizes to fit whatever your pick and place, vacuum holding, degassing, or vacuum evacuation process may call for. These units have been used in a multitude of applications and the Adjustable factor makes them versatile enough to fit a production line with changing needs.

These are all examples of how an E-Vac pick-and-place system is just a solenoid valve away from automation.

The Adjustable E-Vacs have a few benefits that may go unnoticed if one is not keen to exactly how they are constructed and function. This sets them apart from many vacuum generators. When dealing with vacuum generator applications such as pick and place, having a part that is always the same is easiest. This is not always the case. Sometimes it is not just the dimensions of the part that changes, sometimes the material changes or even the surface finish of the part. This is where the ability to change from a porous to non-porous vacuum generator is extremely helpful. Generally this means the material of the parts getting picked up will allow air flow through them (paper, cardboard, wood) or not (plastic, glass). A porous vacuum generator will pull more flow through the part material to hold the vacuum, a non-porous vacuum generator will pull less flow and achieve higher vacuum levels.

To better understand the difference between porous and non-porous, we’ve written about that. Check out Tyler Daniel’s blog on the difference between the two here. The beauty of the Adjustable E-Vac is that it can easily convert from porous to non-porous with a simple adjustment. This is a great feature for a job shop that may change materials they are cutting or engraving on their machines and need to adapt in a moments notice for the job at hand. This could also reduce the number of vacuum generator variances a store room may need to keep on hand for a series of production lines and help to reduce the chance an incorrect model is installed on a machine due to fewer variants.

Adjustable E-Vac

Another benefit which can be helpful in a production environment that has an E-Vac picking up dirty or debris ridden material is that the Adjustable E-Vacs can be disassembled and cleaned. Picking steel sheets off a laser cutter in order to remove the scrap that has a volume of spatter / dust can cause an accumulation of debris on the internals of any vacuum generator. By unscrewing the plug from the body the Adjustable E-Vac can be easily cleaned and all passageways maintained at a level to offer continual performance.

No matter what, the adjustability coupled with minimum components and fastener free disassembly of the unit are two great features that can help minimize machine downtime, lower number of parts kept on hand for machines, and ensure optimal performance no matter what the requirement is for the vacuum generator. If you would like to discuss further, please contact us.

Brian Farno
Application Engineer
@EXAIR_BF
BrianFarno@EXAIR.com

People of Interest: Giovanni Battista Venturi March 15, 1746 – April 24, 1822

Giovanni Battista Venturi was born in 1746 to an affluent family in Reggio, Italy. An aspiring student, Giovanni was ordained as a priest and a professor by the age of 23. An avid historian of science at the University of Modena, he was the first to emphasize Leonardo da Vinci as a scientist rather than just an artist as he’s more commonly known. Despite his love for history, it wasn’t long before the University of Modena became aware of his talents in mathematics where they appointed him as professor of geometry and philosophy in 1774. During his tenure at the University of Modena, Giovanni was promoted to the Professor of Experimental Physics, served as the Duke of Modena as the State engineer and auditor, later serving diplomatic roles in both France and Switzerland.

Giovanni is most well-known for his work in developing what is now known as the venturi effect. In 1797, he published a study on the flow of water through short cylindrical tubes. It wasn’t until 1888 that Venturi’s design was applied to something practical when a man named Clemens Herschel received a patent for the first commercial venturi tube. The original purpose of the venturi tube was to measure the amount of water used in individual water mills and is still used to this day as a means of measuring fluid flows.

Venturi tube.jpg
Venturi Tube

The venturi effect is a principle in fluid dynamics and states that a fluid’s velocity must increase as it passes through a constricted pipe. As this occurs, the velocity increases while the static pressure decreases. The pressure drop that accompanies the increase in velocity is fundamental to the laws of physics. This is known as Bernoulli’s principle. Below is an illustration of how the venturi effect works inside of a constricted tube.

venturi

In everyday life, the venturi principle can be found inside of many small engines such as lawn mowers, gas powered scooters, motorcycles and older style automobiles. Inside the carburetor, there is a small tube through which filtered air flows from the intake. Inside of this tube is a short narrowing. When the air is forced to constrict, its velocity increases and creates a vacuum. This vacuum draws in fuel and mixes with the air stream causing it to atomize.  As the throttle valve is opened further, more fuel is forced into the engine. This increases the RPM and creates more power.

inlineworks
In-Line E-Vac

This principle is also applied to EXAIR’s line of E-Vac products to create vacuum. The .gif below illustrates how an In-Line E-vac works. (1) Compressed air flows through the inlet (2) and is directed through a nozzle, constricting the flow of air. (3) As the air stream exhausts, it expands causing a decrease in pressure and an increase in velocity prior to passing through the venturi. (4) A vacuum inlet tangential to the primary airflow is located at the suction point between the orifice and the venturi. (5) The airflow that is drawn through the vacuum inlet mixes with the primary airstream, then exhausts on the opposite end.

The venturi effect is used in a variety of other EXAIR products used for cooling, drying and cleaning, in addition to the vacuum generators. If you have a process in your facility that may benefit from an Intelligent Compressed Air solution, give us a call. We’d be happy to discuss your application and implement a solution to both reduce your compressed air costs and improve worker safety.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

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

Building an E-Vac Vacuum Generator System

EXAIR’s In-Line and Adjustable E-Vacs are a powerful compressed air powered vacuum generator. They’re a low-cost way to create a vacuum for a variety of different applications: pick and place, clamping, chucking, lifting, surface mounting, and vacuum forming are just some of the possibilities. Both the In-Line and Adjustable E-Vacs are available in a variety of different sizes and flows and can accommodate a wide range of applications.

With no moving parts to wear out, EXAIR’s E-Vacs are virtually maintenance free when supplied with clean, dry compressed air. In-Line E-Vacs are available in two different styles: High Volume, Low Vacuum for use with porous materials and Low Volume, High Vacuum for use with non-porous materials.

For pick and place or lifting applications, vacuum cups will be necessary. With a wide variety of different vacuum cups available: Small Round, Large Round, Oval, and Bellows, we can accommodate nearly any size or shape material. For heavier materials, round cups with cleats provide rigidity and ensure that the load remains stable. For applications on textured or uneven surfaces, Bellows style cups have convolutions that allow for the cup to quickly decompress when it touches the surface of an uneven part or material. To determine the most suitable cup, we must consider the weight of the material and the orientation it will be lifted.

Vacuum cups

If it is being lifted with the vacuum cups positioned horizontally, use a safety factor of 2. For applications where the part or material will be lifted vertically, use a safety factor of 4. This safety factor is then multiplied by the weight of the material. You’ll then need to determine how many vacuum cups are needed. No more than 4 vacuum cups should be used with any one E-Vac. Consider the size/shape of the material to be lifted and place vacuum cups accordingly to evenly distribute the weight. Heavier and larger materials may necessitate the use of more than one E-Vac.

The weight a particular cup can hold at a given pressure is shown in the chart below. Once you’ve determined a suitable cup based on the weight and orientation of the lift, a variety of other accessories are also available.

vacuum cup weights

The vacuum port of the E-Vac has an NPT thread, vacuum cups can be installed directly in this inlet. For applications where the vacuum cup(s) are remotely located, we offer polyurethane vacuum tubing as well as a variety of different fittings to connect them. Both 1/4” and 3/8” O.D. sizes are available in 10’ lengths up to 50’. Simply indicate the model number of the tubing and add the length with a “-“ at the suffix. In addition to fittings and tubing, vacuum check valves are also available. These can be beneficial if there is potential for fluctuations in the compressed air pressure or supply. In the event that there is a significant drop in pressure or loss of compressed air supply, the check valve will ensure that the load remains stable.

To minimize the sound level and ensure you’re adhering to OSHA 1910.95, we have Standard Mufflers as well as Straight Through Mufflers. The Straight Through Mufflers offer the best level of sound reduction, up to 26 dBA!!

E-Vac Mufflers

With all of the different options making a selection can seem like a daunting task. If you’re struggling to determine the most suitable E-Vac and Accessories for your application, give an Application Engineer a call today!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@Exair.com
Twitter: @EXAIR_TD