E-Vacs: Shrinking Foam Packages

In-Line E-Vac Family

A foam manufacturer was looking for a way to reduce the size of their shipping packages.  The type of product was a polyurethane open-cell foam that they would place inside plastic bags to ship.  With shipping charges, the dimensional weight, not actual weight, is used, and it can be very costly.  Since it was open-cell foam, they wanted to evacuate the air from the plastic bags.  This would decrease the package volume and reduce shipping costs dramatically.

The company gave me some details on the product and their process.  The polyurethane foam had a density of 1.1 lb./ft3 (18 Kg/M3), and they were bagging pieces of the foam in plastic bags with the dimensions of 30” long by 10” diameter (0.75m long by 0.25m diameter).  They attempted to use a shop vac to reduce the volume; but, it was too loud and too cumbersome for their process.  They also noticed that the vacuum level was not enough to maximize the shrinkage.  They searched the internet for a better way, and they found the E-Vac™ Vacuum Generators.  They contacted EXAIR to get more information.

The EXAIR E-Vacs use compressed air to create a vacuum by a venturi method.  It can reach vacuum levels up to 27” Hg (91 kPa).  They are very compact and lightweight, and they do not have any moving parts to wear.  So, they are very durable and long lasting in systems with cycling or continuous operations.  In comparison, a typical electric vacuum has a vacuum pressure near 6” Hg (20 kPa).  With the EXAIR E-Vac having a vacuum level 27” Hg (91 kPa), we can draw out much more air to reduce the volume.

At EXAIR, we pride ourselves on customer service.  With this application, I was able to setup a representative sample for testing.  I shot a short video to show the power of our smallest E-Vac.  The video shows a representative sample with a smaller bag.  You can see the volume change with polyurethane foam.

In addition to the video, I was able to calculate the time to evacuate the package to 27” Hg (91 kPa).  EXAIR manufactures seven different sizes of High Vacuum E-Vac Generators with different flow ranges.  The above customer requested an evacuation time in about 30 second.  With Equation 1, I can determine the correct E-Vac size to meet the requirement.

Equation 1:  q = V * ln(p0 / p1)  / t
q = Vacuum flow rate (SCFM)

V = enclosed volume (ft^3)

p0 = atmospheric pressure (“Hg)

p1 = end vacuum pressure (“Hg)

t = evacuation time (min)

Details:
Volume of cylindrical plastic bag: V = 1.36 ft3

Atmospheric air pressure: p0 = 29.92” Hg

Final absolute air pressure: p1 = (29.92” Hg – 27” Hg) = 2.92” Hg

Time to evacuation: t = 0.5 min.

Thus,

q = V * ln(p0 / p1) / t

q = 1.36 ft3 * ln(29.92” Hg / 2.92” Hg) / 0.5 min

q = 6.3 ft3/min or 6.3 SCFM

From the specification on our E-Vac, I was able to recommend the model 810013M.  At 80 PSIG, this model has a vacuum flow rate of 6.85 SCFM; plenty enough to hit the target time.  After installing the E-Vac in their packaging process, they were able to reduce the size by almost 70%.  This was very helpful in reducing the dimensional weight for each shipment; saving the company and their customers much money.

If you would like to send samples in for vacuum test or need calculations for performance improvements, EXAIR Application Engineers will be happy to assist you.  EXAIR always likes to go that extra mile for our customers.

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

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

EXAIR’s E-Vac Vacuum Generators & Accessories

vcacc

EXAIR’s In-Line and Adjustable E-Vacs are powerful compressed air powered vacuum generators. 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.

In addition to the vacuum generators themselves, EXAIR offers a variety of different accessories to help you build a complete system. To minimize the sound level and ensure you’re adhering to OSHA 29CFR 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!!

890001
Straight through mufflers are available from 1/4″-1″ MNPS

With no moving parts to wear out, EXAIR’s E-Vacs are virtually maintenance free when supplied with clean, dry compressed air. To maintain proper operation of your E-Vac, installation of an Automatic Drain Filter to remove any particulate and moisture from the air supply is necessary. In addition, oil removal filters are also available if your compressed air supply contains any oil as is common in many compressed air systems.

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.

vacupfam
EXAIR’s family of vacuum cups

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. For example, a 900795-30 would be 30′ of 1/4″ O.D. tubing. 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 held.

push_lock_t
Push-in Swivel Tee Connector

With all of the different options making a selection can seem like a daunting task. A highly trained EXAIR Application Engineer is ready and available to help you!! With just a few quick details, we can help advise you about the proper size E-Vac generator for your application as well as recommend the most suitable cup and accessories. Give us a call, shoot us an e-mail, or reach out to us online via chat and we’ll make sure you have a complete vacuum solution ASAP with all parts ready to ship from stock!

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

Vacuum Generator System Selection – EXAIR E-Vacs

E-Vac Vacuum Generators are a highly efficient, versatile compressed air vacuum pump. Their versatility allows them to be adapted to many applications such as pick and place, clamping or vacuum forming. They’ve also been used in more unique applications like wood veneer pressing and basketball deflation.

EXAIR manufactures (3) types of E-Vacs – Low vacuum generators for porous materials, like cardboard, generating up to 21″ Hg with vacuum flows as high as 18.5 SCFM. Our high vacuum generators, designed for use with non-porous materials like glass or steel sheets, produce vacuum levels up to 27″ Hg and up to 15.8 SCFM of vacuum flow. The adjustable generators provide flexible vacuum performance, up to 25″ Hg and 81 SCFM,  which can be easily adapted to meet the application.

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

 

When making a selection, there are a few key areas you want to consider:

Is the material porous or non-porous?

  • This will allow you to select the proper type of vacuum generator to fit the application and the type of vacuum cup best suited for the process.

 

What is the weight of the part and how will it be lifted?

  • If the part is being lifted where the vacuum cups will be positioned horizontally, like on top of a sheet of glass, you want to use a safety factor of 2 times the actual weight of the part. In processes requiring the cups be positioned vertically on the part, such as picking up a sheet of plywood and hanging it on an overhead conveyor, a safety factor of 4 would be used.

 

How many Vacuum Cups do I need?

  • Consider the quantity and placement to evenly distribute the weight for safely moving the material.
  • Depending on the maximum vacuum the generator produce, how much weight can each cup lift?
  • Make the cup selection per the following chart

 

Once you have selected the type and number of cups needed, you can then begin to look at which additional accessories items you might need.

  • Filters – supplying clean, dry air is key for maintaining optimal performance. An automatic drain filter  can be used to remove any water or contaminants in the supply line. If there is oil present, consider using an Oil Removal Filter.
  • Mufflers – help to reduce the noise level without restricting the airflow. We offer 2 different styles – Standard and Straight Through. Standards mufflers are a good choice where the supply air is clean and dry. These mufflers can only be used with the porous and non-porous generators. The Straight Through mufflers reduces sound levels by up to 26 dBA and are the better choice in processes where dirt or particulate may be present.
  • Tubing and Fittings – polyurethane tubing is available in 10′ sections up to 50′ for processes requiring the vacuum cups be placed in a location that wouldn’t allow for direct mounting to the NPT vacuum port on the generator or where multiple cups are needed. You want to keep the length of tubing as short as possible though for effective pickup and release time.
  • Check Valve – will maintain vacuum on the load if the supply pressure were to drop or be lost during operation.

For additional assistance selecting the proper E-Vac and accessories for your process, please contact an application engineer at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

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

Custom Air Amplifiers To Meet Most Any Requirement

When I think of “special” in regard to Air Amplifiers, I’m more inclined to think of the applications they can be used in. I mean, the Air Amplifier itself is about as straight-forward as an engineered compressed air product can be:

Air Amplifiers use the Coanda Effect to generate high flow with low consumption.

Considering the simplicity of the product itself, they can be used for a large variety of “typical” applications:

  • Cooling
  • Drying
  • Cleaning
  • Ventilation
  • Fume Exhausting
  • Dust Collection

There are no shortage of “special” applications either.  They’re used successfully in Air Operated Conveyance applications (when the stronger vacuum head of a Line Vac isn’t required) and we’ve even got a customer who uses one instead of an E-Vac Vacuum Generator for a “pick & place” operation…they’re picking up small, porous fiber discs (sort of like a coffee filter) one at a time, and the E-Vac wanted to pick up a good part of the whole stack, no matter how low they turned the pressure.  And of course, I can’t think of anything more special about Air Amplifiers than this:

You have to read it to believe it.  Follow the link and click on “Case Study: Roaring Banana Breath”

With fifteen distinct models to choose from in a range of sizes (3/4″ to 8″,) materials (aluminum or Stainless Steel) and even a High Temperature model that’s rated to 700°F (374°C), we’ve still made a fair number of Custom Air Amplifiers too…thirty-four, to be exact, as of this writing.

I won’t bore you with all the details – I can’t, actually, because some of them are proprietary* – but here are some “regular” examples of “special” accommodations:

  • Connections: EXAIR Air Amplifiers have smooth bores on the inlet & outlet plenums that you can hose clamp a hose (or round duct) to if you need to get air flow from, or to, one place or another.  Sometimes, though, they’re going in to an existing system, so we’ve made them with flanges (150#RF and Sanitary Tri-Clamp, for example) or threads (NPT or BSPP.)  If you want to use something other than a standard hose or duct line, we can help.
  • Material of construction: Our durable, lightweight aluminum Super & Adjustable Air Amplifiers are just fine an awful lot of the time.  Our type 303 Stainless Steel Adjustable Air Amplifiers will hold up to heat and corrosives.  We’ve also in PTFE (Teflon™) as well as a range of metal alloys to meet specific corrosion or wear conditions.  If your environment calls for a little something extra, we can help.
  • Assembly: Super Air Amplifiers are fitted with a stock shim that gives you published performance.  We’ve got other thicknesses, though, if you need more (or less) flow, though.  Adjustable Air Amplifiers are, well, adjustable…you just thread the plug in/out of the body until you get the results you want.  Sometimes the user knows what shim they want in a Super Air Amplifier, or what gap their Adjustable Air Amplifier needs to be set to, and we can assemble it accordingly.  If you have a ‘tried-and-true’ performance setting and want it met right out of the box, we can help.
  • Assembly, part 2: Good engineering practices call for lubrication on O-rings and threaded connections, and we use high quality, general purpose compounds when assembling our Air Amplifiers.  These are detrimental, however, in certain situations (silicone exclusion areas, I’m looking at you.) If certain chemicals or compounds are prohibited by your application, we can help.

*Let’s say you’ve done the “heavy lifting” to call out one (or more) of these special design features.  If we make a custom product (and that’s not just Air Amplifiers, by the way) using directions based on your time and labor, we’ll treat that product as proprietary to you, and you alone.

EXAIR has 208 catalog pages worth of Intelligent Compressed Air Products on the shelf…8 of those pages are our Air Amplifiers.  If you want to talk about customizing one to meet your needs, give me a call.

Russ Bowman
Application Engineer
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