Tag: vacuum generator

Vacuum Evacuation Time for E-Vacs

Published on by John BallLeave a comment

A tank manufacturer was building specially designed tanks for their customer. These tanks were to hold cryogenic materials, so they had to create an outer shell to hold a special type of insulation material.  This shell maintained a 1/2 inch (13 mm) gap around the tank.  The overall dimensions of the cylindrical tanks were 10 feet (3 meters) in diameter and 43 feet (13 meters) in length.  The internal volume of the gapped area was 56.1 cubic feet (1560 liters).  With this type of insulation, it had to be under a negative pressure, or vacuum, to help facilitate the insulation properties.  So, when the tanks were completed, they had to check for leaks between the shell and the tank.  The requirement was to draw a vacuum to 21” Hg  and to hold it at that level for 30 minutes.  As the tank manufacturer researched vacuum pumps to test their design, they came across EXAIR.

Being that they were not familiar with EXAIR E-Vacs, they wondered how they worked. I explained that the E-Vac uses compressed air to create a vacuum by a venturi method.  It can reach vacuum levels up to 27” Hg in a very compact and lightweight design.  Being that they do not have any moving parts, they are very durable and long lasting in systems with on/off cycling or continuous running.  The tank manufacturer was very intrigued by this concept as they had electric vacuum pumps fail in the past.

He wondered about the evacuation time to get to 21” Hg of vacuum. The idea for the leak test was to reach the vacuum level and turn a valve off to isolate the area.  From there, they would watch a gage to see if they were losing vacuum.  If so, then they would have to find and fix the leak and recheck.  If the vacuum pressure held, then they could fill the area between the shell and the tank with insulation material; use the E-Vac to put it under vacuum; and cap.  Because the volume was large and time was a concern, I suggested the model 840060M.  This had the highest vacuum flow rate and can reach a vacuum level of 25” Hg.

Adjustable E-Vacs
Adjustable E-Vacs

To help explain a little better about vacuums, when you are near atmospheric pressure, you have the highest air flow rates. As the vacuum levels rise, less air is present to be drawn out.  When you reach the vacuum pump capacity or complete vacuum, the flow rate is zero.  You can notice this with your vacuum at home.  As you turn the vacuum on, the air is rushing in (the highest flow rate/very low vacuum pressure).  As you cover it with your hand, the vacuum pressure increases and the flow rate decreases to zero (no flow rate/highest vacuum pressure). To figure the amount of time to reach a certain vacuum level, we have to take into consideration the different flow rates as the vacuum level continues to increase.  The equation that we use is below:

Equation 1:  t = V * ln(p0 / p1)  / q

t = evacuation time (min)

V = enclosed volume (ft^3)

p0 = atmospheric pressure (“Hg)

p1 = end vacuum pressure (“Hg)

q = flow rate of vacuum pump (SCFM)

With the performance data of the model 840060M E-Vac, we can start to calculate the time to reach 21” Hg vacuum. A couple of details are required to make the equation work properly.  Just as a note, the end vacuum pressure, p1, has to be converted to an absolute pressure. This will equate to 29.92” Hg – 21” Hg = 8.92” Hg (absolute).

Here are the details for Equation 1:

V = 56.1 ft^3 (above)

p0 = 29.92” Hg (absolute start)

p1 = 8.92” Hg (absolute target)

q = 70 SCFM (cataloged at 80 psig)

Thus,

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

t = 56.1 ft^3 * ln(29.92” Hg/8.92” Hg) / 70 SCFM

t = 0.97 minutes

For this application, the model 840060M worked great for both procedures. With less than 1 minute to get to the desired set point, it didn’t hinder production for leak checks or to vacuum set the insulation. If you have a timing sequence with vacuum chambers or “pick and place” systems, you can use this equation to find the best E to meet your goal.  If you need any additional help, you can always contact an Application Engineer at EXAIR.

John Ball

Application Engineer

Email: johnball@exair.com

Twitter: @EXAIR_jb

Stainless Steel Line Vac turns Super Sack into a Large Vacuum Bag

Published on by Neal RakerLeave a comment

LV PE pellet application2

I had an interesting application from a guy in Kuwait who worked at a plastics plant. They worked with polyethylene pellets for molding processes. In his introduction, the customer said he was looking for something like our Chip Vac product but he wanted to use it with a super sack platform that they elevate up to a high position to allow for cleaning in and around their silos. I mentioned to him that we do have the Chip Vac available to work with a 110 gallon drum. His response was that he knew about that but was not interested as they were set up to move the larger super sacks around their plant. You can see one such set-up in the above photo.

His problem was that he needed a quick and easy way to get the loose PE pellets into his super sack without using a broom and shovel. We had just the solution.

Many years ago when we introduced the Chip Vac product, we did so as a result of customers who knew about our Line Vac but wanted it to be used on a drum. So, we adapted the Line Vac to have the proper, 2 NPT threads necessary to screw into the larger of the two holes in the top of a typical drum. In this situation, we were working the development that we did so long ago in reverse. So, it was a very easy recommendation to set the customer up with a Line Vac to aid in the vacuuming up of the polyethylene pellets and do so in the manner the customer wanted.

After a little discussion to sort out the type of material and the size Line Vac that the customer wanted, we ended up settling on a 1-1/2” Stainless Steel Line Vac Kit, model 6963. The 1-1/2” size allowed for easy connection of a standard size vacuum hose for easy manipulation around the clean-up area. The customer opted for the stainless steel over an aluminum unit as they wanted to be absolutely certain that the product could stand up to their typically rough conditions. He also wanted the kit so he could mount the Line Vac to his platform and have clean, dry air going to the Line Vac to keep it running well for a longer time. Below is a rough sketch of the customer’s idea about how to marry the Line Vac to his super sack platform.

 

LV setup

You can notice from the sketch that the customer already had his filtration system thought out to allow the conveying airflow back out of the bag.

The key to this application and the feature that I want to point out is the adaptability of the Line Vac to fit into just about any application. We do have the Industrial Housekeeping products available for ready to use solutions. But, if you have a similar situation where you have part of your “system” that you like for one reason or another, we’re more than willing to discuss what you have at your facility to help you best determine how we can implement a solution that you are happy with. Likewise, if we feel that there is a better way to approach your application, we will be sure to let you know that too!

Give us a ring or send us an e-mail to discuss the specifics of your application today. We’re here to help.

Neal Raker, International Sales Manager
 nealraker@exair.com
@EXAIR_NR

EXAIR E-Vacs For Pick-And-Place Applications

Published on by Lee EvansLeave a comment

Over the last two weeks I’ve trained a number of our distributors on EXAIR products.  We’ve discussed the benefits of engineered compressed air products, the way these products can impact a company’s bottom line, and how they work.

One of the topics which is sure to produce good conversation is our vacuum generator product line, the E-Vacs.  Using a compressed air powered venturi to produce vacuum, the E-Vac is attractive for a number of applications because the vacuum flow is instantaneous.  This means we can produce vacuum only when and where it is needed rather than keeping a vacuum pump in continuous operation.

Battery snip
Power supplies to be lifted with EXAIR E-Vacs

This instantaneous nature of the E-Vac was recently attractive to an end user in need of a better method to handle electronic power supplies used in their computer production process.  They wanted the lifting and placement of the power supplies to be semi-automated, with an operator turning the lifting system on and off.

This type of application is perfect for an E-Vac.  In order to determine the best solution, for this or any E-Vac application, we have to first determine the following:

  1. Is the material/item to be lifted porous or non-porous?
    1. Porous materials will have leakage through the material itself, or through inconsistencies in the material surface. Items such as cardboard, fabrics, or a golf ball are considered porous.
    2. Non-porous materials will not have leakage through the material. Items such as smooth glass and flat plastics are considered non-porous.
  2. What is the weight of the item to be lifted?
  3. How will the item be lifted?
    1. Will the vacuum cups mount to the top of the workpiece to the side? This will determine if the suction cups will be in a horizontal or vertical plane when lifting the product.
Battery dims
Dimensions of the workpieces

Using this information we can determine the proper safety factor to apply (2 for horizontal orientation of the vacuum cups, 4 for vertical orientation), and the potential vacuum cups to be used.  Then, based on size of the workpiece and space constraints we can select the proper vacuum cups.  And finally, using charts on file with the EXAIR Application Engineering department, we can select the correct E-Vac or E-Vacs for the application.

If you have a pick-and-place need in your facility, contact an EXAIR Application Engineer.  We’ll be happy to help choose the right components for your setup.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

If It Ain’t Broke…It Could Still Improve

Published on by Russ BowmanLeave a comment

…Don’t fix it, or so the saying goes. Sometimes, though, we have the opportunity to talk to compressed air product users who are looking to redefine the term “ain’t broke.” There are, for instance:

*People with end-use compressed air devices that came with their machines, which “ain’t broke,” but may be louder, or costing more to operate, than an engineered solution. A prime example of this is replacing an open-ended blow off with a Super Air Nozzle. We’ve got (69) distinct products in our Air Nozzles & Jets line…we’re sure to have one that’ll install quickly and easily, with immediately noticeable improvements. Improvements including a more comfortable work environment from lower noise levels and a lower air consumption which will provide your compressor relief and save air for other or future applications.

EXAIR Model 1100 Super Air Nozzle installs easily on copper lines, with a simple compression adapter.
EXAIR Model 1100 Super Air Nozzle installs easily on copper lines, with a simple compression adapter.

*Expansions to processes, or add-ons to systems. We’ve helped out more than a few customers in the automotive industry – from manufacturing to detailing – who are now able to move more vehicles through by enhancing their existing central vacuum systems with EXAIR Model 6292 Vac-u-Gun Transfer Systems. They use these guns at work stations to deliver scrap and debris into the central vacuum system, the Vac U Guns have shortened the time spent removing scrap and trim by boosting the vacuum flow at the work station.

With three systems to choose from, we've got the portable vacuum system you need.
With three systems to choose from, we’ve got the portable vacuum system you need.

*Perhaps something “ain’t broke,” but it’s also not as safe as it could be. Our E-Vac Vacuum Generators and Vacuum Cups are perfect solutions for pick-and-place applications that keep operator’s hands away from machinery, while still allowing for the safe removal of manufactured parts. Actually, though, if the particular situation is “not as safe” enough to constitute an OSHA violation, we would certainly classify that as “is broke.” Call me NOW. I can help.

EXAIR In-Line E-Vacs and Vacuum Cups...ideal for quick, easy pick-and-place systems.
EXAIR In-Line E-Vacs and Vacuum Cups…ideal for quick, easy pick-and-place systems.

*”Bucket and Ladder” material transfer methods may be described as “ain’t broke” (usually by people who aren’t carrying the buckets up the ladder) but they certainly can be time and labor intensive. EXAIR Line Vacs have been solving these applications for years. From packing peanuts to steel shot (and just about anything in between…so long as it’ll fit inside a hose from 3/8” to 6”,) we’ve got it covered. Check this out and see for yourself:

Whether or not you’d call your current situation “broke” or not, if you’re thinking about it, I bet it’s worth talking about. Give us a call.

Russ Bowman
Application Engineer
Find us on the Web
Follow me on Twitter
Like us on Facebook