Tag: compressed air product applications

E-Vac’s: Choosing The Right Vacuum Generators and Cups For Non-Porous Object Lifting

Published on by Russ BowmanLeave a comment

For years, users worldwide have been building pick-and-place vacuum lifting systems using EXAIR E-Vac Vacuum Generators and Vacuum Cups. One of the very first calls I took after I started here in 2011 was from a customer who wanted to make an automated bench-top system for use in the packaging of small blister packs of consumer products. These products were small, so it was fairly easy to specify a compact and inexpensive setup that was easy on his compressor load. Which was good, because his compressor wasn’t all that big either. Here’s how we went about it:

Each product going into a blister pack was about the size of a roll of pennies, but much lighter, as they were hollow plastic tubes with lip balm in them. Our Model 900762 1″x0.5″ Oval Vacuum Cups were a perfect fit – they’ll hold half a pound with only 5″ Hg vacuum, so even if they didn’t make a perfect seal on the tube (which weighs just shy of an ounce), they’d work just fine.

With objects that weighed next to nothing, and a smooth, non-porous surface for the Vacuum Cups to seat on, we didn’t need a whole lot of vacuum generation power, so we went with a Model 810002M In-Line E-Vac High Vacuum Generator. Using a selection of our Vacuum Tubing & Connectors, they constructed an automated lifting system to package six of the tubes in their blister packs at a time.

This was a small, simple system that didn’t require an awful lot of engineering…our smallest Vacuum Cups and E-Vac Vacuum Generators were more than capable of handling the load. Other times, we have to (EXAIR Application Engineers actually say we “get to”) use math & physics to come up with the right system. Even when they require some of the proverbial “heavy lifting,” they can still be fairly straightforward. Consider this application for a steel plate:

  • 1/2″ steel plate, 4ft x 6ft, weighing ~490lbs.
  • Picking up from the top of a stack and placing onto a laser cutter.

First, we start with the selection of vacuum cup size. For a plate of this size, multiple cups are necessary – even if one vacuum cup was rated for the weight we’re considering, that would be incredibly unstable. Additionally, if one cup fails to make a good seal on the surface, more cups provide redundant protection against potentially dropping the load. We can use this Vacuum Cup Selection Table from the catalog:

Per the instructions, we multiply the weight of the object (490lbs in this case) by a safety factor of two if we’re picking it up horizontally from the top, or four if we’re picking it up vertically from the sides. Our Model 900761 6″ Large Round Vacuum Cups are rated at 148.8lbs each, and since:

980 lbs (2x the plate’s weight) ÷145.8 (rating in lbs for each Cup) = 6.7

We need at least seven of them to safely handle this load. Let’s use eight, though, for symmetry. If you’re wondering why I picked the weight capacity associated with 21″Hg when our High Vacuum In-Line E-Vacs can generate 27″Hg, it’s just in case one of the cups doesn’t make a perfect seal to the surface…we still want to be able to hold the plate, even if there is a little vacuum leakage. So, we’re overcompensating to add to our already calculated safety factor in the application.

Next, we’ll select our E-Vacs. For safety’s sake (I can’t stress how badly I DON’T want to be party to dropping a 490lb steel plate on anything, or anyone), we’ll use four E-Vacs. Since each E-Vac will be servicing two of our largest Vacuum Cups and the vacuum lines aren’t all that long, but the weight of the object being picked up is significant, I’ve picked our Model 810013M High Vacuum E-Vacs for their moderate vacuum flow (1.31 SCFM @24″Hg) and high vacuum level rating (27″Hg):

Each of our four E-Vacs will pull vacuum on two vacuum cups, in a ‘crisscross’ pattern so that if one fails, it doesn’t unbalance the load.

If the object is to be picked up from the side, then we use a 4x safety factor for the object’s weight. For example, a customer who replaces truck windshields transports them in vertical racks on their service trucks. They wanted to use one E-Vac and three Vacuum Cups for the manual lifting rig they had designed. One piece of a two-piece windshield is about 2ft x 3ft, and weighs about 50lbs.

200 lbs (4x the windshield’s weight) ÷ 3 (number of Cups specified) = 66.7 lbs per Vacuum Cup

Based on a weight rating of 73.2lbs @21″Hg, we used three of our Model 900759 4.25″ Large Round Vacuum Cups for this application. Since an operator wipes down the glass immediately before picking it up, and has good control of the lifting rig (so they can ensure the cups are properly seated on the surface), we selected a Model 810006M High Vacuum E-Vac, which still has a decent amount of vacuum flow (0.77 SCFM @24″Hg) in case of any leakage, and a 27″Hg vacuum level rating.

EXAIR also carries a comprehensive selection of Connector Fittings and Vacuum Hose or Tubing to connect these kinds of systems together. If you want to spec out a lifting/pick-and-place system, I’m here to help – give me a call.

Russ Bowman, CCASS

Application Engineer
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Boosting Ventilation With Air Amplifiers

Published on by Russ BowmanLeave a comment

Entering a confined space comes with a number of risks:

  • Physical hazards: mechanical equipment, falling objects, structural collapse, etc. Historically, these account for about 20% of fatalities associated with confined space entry.
  • Engulfment hazards: that’s a less horrific way to say “buried alive.” These are similar to some physical hazards, except the danger is from asphyxiation instead of being crushed. A prime example of this would be a farmworker falling into a grain silo in such a way that their head is submerged in the volume of grain. About 11% of confined space entry fatalities involve engulfment accidents. EXAIR Line Vacs are actually used in emergency responses to these.
  • Atmospheric hazards: Without adequate ventilation, carbon dioxide can build up, displacing the oxygen that workers need to breathe. Toxic and flammable gases are in this category as well, and whether workers are asphyxiated or poisoned, failure to provide a safe atmosphere accounts for almost 60% of confined space entry deaths.

Before workers enter a confined space, permits are oftentimes required. Atmospheric monitoring and ventilation are key aspects of such permits: Monitoring to ensure an adequate level of oxygen and the reduction of toxic & flammable gases to safe exposure limits, and ventilation to make sure that happens. It’s generally recommended to have ventilation/exhaust equipment capable of providing 20 air changes per hour.

EXAIR Air Amplifiers are an easy & reliable choice for providing the required ventilation. With no moving parts to break or electrical components to fail, all they need is a supply of compressed air. So, how do we choose the right one? Since we know we need 20 air changes an hour, the first step is to determine the volume of the space. Let’s say we need to enter a 10ft x 6ft x 6ft tank:

  • 10ft x 10ft x 12ft = 1,200 cubic feet
  • 1,200 cubic feet of air X 20 changes per hour = 24,000 cubic feet of air to change per hour
  • 24,000 cubic feet/hour ÷ 60 minutes/hour = 400 cubic feet per minute

In this case, we could specify a Model 6042 2″ Aluminum Adjustable Air Amplifier, which uses just 21.5 SCFM @80psig to generate a total developed flow of 430 SCFM (see table above). Minus the 21.5 SCFM of compressed air flow, that means it’s drawing 408.5 SCFM in from the tank.

If additional airflow is required, the ring gap of the Adjustable Air Amplifier can be easily increased by threading the plug out of the body until the needed flow is achieved. A Pressure Regulator can also be used to ‘fine tune’ the compressed air supply, and hence, the ventilation flow.

EXAIR Air Amplifiers are a simple, low-cost way to move air, smoke, fumes, and even light materials. If you’d like to find out more, or if you have a potential application to discuss, give me a call.

Russ Bowman, CCASS

Application Engineer
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Robert Boyle and Boyle’s Law

Published on by Al WooffittLeave a comment

We’ve written many blogs about our intelligent compressed air products; we have a lot of great products to talk about (our Vortex Tubes are my favorite). Occasionally, we like to talk about certain people of interest, or people that have had an impact on the compressed air industry. In this blog I am going to cover one of those people: Robert Boyle.

Born on January 25, 1627, at Lismore Castle in County Waterford, Ireland. He was an Anglo-Irish natural philosopher, chemist, and physicist, and he explored various other fields of study. In 1661, he published his book The Sceptical Chymist, which many regard as the cornerstone of modern chemistry.

Even though his main focus was chemistry, one of Boyle’s most notable scientific contributions is what we now call the first gas law, aptly named Boyle’s Law. Boyle’s Law explains how pressure and volume relate in a closed space when considering the mass of an ideal gas. Boyle, along with his assistant Robert Hooke, utilized a closed J-shaped tube and added mercury from the open end, which caused the air on the opposite side to compress due to the pressure. After conducting this experiment with various amounts of mercury, Boyle concluded that the pressure of a gas is inversely related to the volume it occupies.

Boyle used a ‘J’ Tube – Sealed on the Short End, and Open at the Long End

This relationship between pressure and volume is of obvious interest to us in the compressed air industry. Nitrogen, oxygen and hydrogen (the three primary components of air) are ideal gases, so are governed by this relationship. This means that if we reduce the volume of a given space, the air inside that space will increase in pressure. This principle plays a key role in various areas of air system design as well, including determining compressor output, reservoir storage, pneumatic cylinder efficiency, and more.

Sadly, on December 31, 1691, Robert Boyle passed away. However, the impact he made on fluid dynamics lives on to this day. At EXAIR we use the pressure and volume of compressed air for our products to make them quiet, safe and efficient. If you have questions about any of our quiet EXAIR Intelligent Compressed Air Products, feel free to contact EXAIR or any Application Engineer.

Al Wooffitt
Application Engineer

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The 30-Day Guarantee Gives You Confidence.

Published on by Al WooffittLeave a comment

When you make a purchase, you want to have confidence that the solution that you’ve spent money on is going to work. With many of the applications that we discuss with customers, the solutions are tried and tested. If your electrical panel is getting too hot, then an EXAIR Cabinet Cooler is exactly what you need. If there’s static on your assembly line, a Gen4 Static Elimination product is the way to go. And if you need to blow off excess water from an extruded pipe, a Super Air Wipe is the perfect fix.

There are plenty of situations where the solution isn’t clear-cut. We believe our products can make a difference, but with so many variables, it’s impossible to just plug everything into a formula and predict the exact outcome. The only way to know for sure is to test. That’s where EXAIR’s 30-day unconditional guarantee comes into play. Every one of our cataloged products is covered by this guarantee. Once you buy one of these items, you have a month to really test it out; change the angle, tweak the operating pressure, or swap out shims. If you manage to find the right setup to fix your issue, awesome! If not, we’ll gladly take it back and give you a full refund! The only thing you need to cover is the shipping to return it to us.

A great example of where testing is key is our Line Vacs. There are several factors to consider: the bulk density of the material, its size, whether it’s abrasive, the desired conveyance rate, and the distance for conveyance – both vertical and horizontal. By using the data we’ve gathered from our controlled in-house tests, we’re going to be able to give you a solid recommendation on which model will suit you best. However, to truly understand how our Line Vac will perform with your specific material and operational conditions, it needs to be put through its paces at your facility. When you buy from us, you get 30 days to try it out risk-free.

At EXAIR, we want to ensure you are getting the best possible solution. Our 30-day unconditional guarantee is one way that we make that a reality. If you would like to discuss how our products can help with your application, give us a call!

Al Wooffitt
Application Engineer

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