Tag: venturi vacuum generator

“Other” Uses For Vacuum Generators

Published on by Brian FarnoLeave a comment

Okay. Throughout our catalog and most of my training, many moons ago, we always stuck to using the E Vac Vacuum Generators as pick and place type units. Hook them up with some suction cups and you can have some fun. However, this isn’t all they can be used for. In fact, I blogged about it over a decade ago not being used for a pick and place operation. Rather, I used it to pull a steady vacuum on a hydraulic brake system in order to pull the fluid through the lines.

My E-Vac Brake Bleeder Setup

Today, I want to show you another trick that I am almost certain I saw when I was a kid on Mr. Wizard. I saw this in High School, learning from one of my amazing educators in the Science department, and then again in college taking basic Chemistry courses. The trick is maybe not something that you would use regularly, but it is a great visualization for something that may help some DIY’ers and even some industrial engineers. So what is the process exactly? Well, it is using a vacuum to “boil” water, except we aren’t really boiling the water, it just appears that way.

That’s right, in this video you can see I have a very small E-Vac Vacuum Generator connected to a glass jar with some water in it. Now there is some condensation in the jar from the water being warmer than the environment we were in. As I energize the E-Vac, you will see the operating pressure go up on the gauge to the right, and you will see the pressure in the jar go down on the vacuum gauge to the left. You can also see just how quickly the small E-Vac removes all the air from the chamber and then begins to build the vacuum, effectively pulling the gas from water, making it appear as though it is boiling due to a temperature increase. Instead, it is actually “de-gassing” the water and removing the oxygen.

This same process can be used in molding operations, epoxy resin processes, and even off-gassing operations. If you can get the surface or container into a vacuum condition, then an Inline E Vac or Adjustable E Vac can be used to evacuate the gases from the fluid within the chamber or area. This makes them more conducive for use without bubbles forming during the curing phase. The size of the E Vac needed for this will be determined by the size of the area and that is exactly what our Application Engineers are here to help with.

If you would like to discuss an off-the-wall idea or de-gassing, feel free to contact an Application Engineer today.

Brian Farno, MBA – CCASS Application Engineer

BrianFarno@EXAIR.com
@EXAIR_BF

In-Line High Vacuum E-Vac Solves Workholding Fixture Problem

Published on by Russ BowmanLeave a comment

Workholding refers to any method of keeping an object in a fixed position while force is exerted onto it. If you’ve ever put something in a clamp or vise to loosen (or tighten) a bolt or screw into it, you’ve performed workholding. In fact, if you’ve ever wrapped a napkin around a cold bottle of your favorite beverage to get a better grip while twisting the cap off, that’s workholding too.

In manufacturing and machining settings, any number of different clamps, fixtures, jigs, chucks, vises, etc., are commonly used for workholding. For efficiency, the main feature of a good workholding device is an easily repeatable setup that can secure the piece quickly, and release it just as quickly. The table of a milling machine, for example, will commonly have t-handle clamps for this.

In addition to mechanically clamping parts, they can also be held in place with vacuum. The basic principle is kind of like an air hockey table, but in reverse: instead of floating the puck on a thin curtain of air being blown out of the holes on the table, it’d be held in place by pulling air back through the holes, to draw a vacuum between the top of the table and the bottom of the puck. Vacuum pump systems can be used for this, but they can get pricey if you don’t already have one (with enough extra capacity) to tie in to. Those pumps have moving parts, so they’re going to need maintenance from time to time as well.

EXAIR E-Vac Vacuum Generators, on the other hand, don’t have any moving parts to wear or electric motors to burn out. They’re compact, they draw rated vacuum as soon as you start supplying compressed air to them, and they drop that vacuum off just as soon as you turn the air off.

For most common workholding applications, we’ll specify an Adjustable E-Vac, for a couple of reasons:

  • Because they’re adjustable, you can quickly dial in different vacuum – and vacuum flow – levels needed to hold parts of different sizes, shapes, and/or weights.
  • They have a large enough throat diameter to pass small amounts of chips or coolant, so the part doesn’t have to be perfectly clean when you place it in the fixture.
The wide throat diameter of the Adjustable E-Vac makes it suitable for applications where small amounts of particulate and/or liquid may be drawn through.

Of course, not EVERY application is a COMMON one…case in point, I had the pleasure of helping a caller from a tool & die company the other day, who wanted to make a fixture to hold a metal block in a V-shaped fixture with two flat surfaces that correspond to the two flat surfaces of the block that won’t be worked on. The idea was to put several holes in each surface, with shallow countersinks for o-rings, so that when the block was set, the o-rings would make a positive seal, and pull vacuum on those holes with an E-Vac. Since there’s a tight seal between the blocks & fixture, and the blocks will be clean & dry, this doesn’t require the chip/coolant passage of an Adjustable E-Vac. And since the cutting & drilling will exert a good amount of force, in several directions, we DO want a high vacuum level to make sure it doesn’t move. At all. No matter what.

For this application, we specified a Model 810023M In-Line High Vacuum E-Vac. It’ll generate 27″Hg worth of vacuum, and in case of any minuscule movement or misalignment of the block, it’ll provide an impressive 2.67 SCFM worth of vacuum flow (to overcome any leakage past the o-rings) and still hold the block in place with 24″Hg.

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

If you’d like to find out more about EXAIR Vacuum Generators for workholding, pick-and-place material handling, vacuum forming/filling/pressing, or any other application where you need any more than a few inches of mercury worth of vacuum, give me a call.

Russ Bowman, CCASS

Application Engineer
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Adjustable E-Vacs For All Kinds Of Vacuum Applications

Published on by Russ BowmanLeave a comment

EXAIR makes three different engineered compressed air products that are capable of pulling vacuum:

  • Air Amplifiers generate a very high vacuum flow (up to 25 times the compressed air flow rate) but not very much vacuum head. This makes them great for fumes, smoke, and airborne dust.
  • Line Vacs generate a moderate vacuum flow and head so they can easily convey bulk solids.
  • E-Vac Vacuum Generators generate a high vacuum head, but not a lot of vacuum flow. They’re commonly used with Vacuum Cups in pick-and-place applications, or a number of other applications where you measure the required vacuum in inches of mercury (the Air Amplifiers’ and Line Vacs’ vacuum heads are measured in inches of water.)

Our Adjustable E-Vac Vacuum Generators are the ones that typically fall into the “number of other applications” category above. While the In-Line E-Vacs are compact and reliably generate rated vacuum on demand, the Adjustable E-Vacs have some distinct advantages in certain cases:

Larger throat diameter. In-Line E-Vacs have a very tight throat, which generally doesn’t matter if they’re just hooked to Vacuum Cups that’ll be placed on a relatively clean surface. The wider throat of the Adjustable E-Vacs means that they can pass small debris from less-than-pristine surfaces that a Vacuum Cup might lift, or shavings that might fall into a work holding fixture on a machine tool. They can even pass liquids, so they’re sometimes used for small spill cleanup.

Adjustability. It’s right in the name, of course, but it IS a big deal. While you can regulate the supply pressure of almost any compressed air operated device to vary the performance level, you can thread the plug into, or out of, the body of an Adjustable E-Vac to literally put it in a whole new performance band. This is beneficial if you’re picking up, or holding down, pieces of different sizes, shapes, and weights. Just loosen the locking collar, make the adjustment, tighten it back up, and it’s ready for use.

With four distinct models to choose from, we can specify one with the vacuum performance and adjustability of range needed for your application. If you’d like to find out more, give me a call.

Russ Bowman, CCASS

Application Engineer
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E-Vac Porous vs Non-Porous materials

Published on by Al WooffittLeave a comment

EXAIR’s E-Vacs are a great solution for many applications including pick and place, chucking, surface mounting, lifting, and vacuum forming. When selecting which is the right model for you, there are several points you need to consider. Although selecting the right vacuum cup size is important, and knowing the size and weight of the part is necessary, one of the main considerations is evaluating the nature of the material you are working with. Specifically, is the material porous or non-porous?

Porous materials, as the name suggests, have many holes in them. This will allow air to flow through them when trying to pull a vacuum. This can be a challenge when trying to use an E-Vac. To overcome this, you need a high vacuum flow. Non-porous materials, on the other hand, will not allow air to flow through them, so a higher vacuum level can be achieved with a low vacuum flow. If you know which category your material falls into, we can select the correct E-Vac.

Cardboard – Photo by OpenClipart Vectors and licensed by Pixabay

 If you are working with porous materials such as paper, cardboard, or some fabrics, we would recommend one of our vacuum generators that produces a low vacuum level and high vacuum flow. With vacuum levels up to 21” Hg and vacuum flows up to 18.5 SCFM, this style generates more vacuum flow to overcome the porosity and leakage. An additional benefit is that they can also be used to lift or hold delicate materials and prevent any warping or disfiguring of the surface due to excessive vacuum.

Glass – Photo by dflamini and licensed by Pixabay

Alternatively, if your material is non-porous, like glass, steel sheet, or plastic, you will need a generator that produces a high vacuum level with lower vacuum flow. EXAIR’s non-porous high vacuum units can achieve vacuum levels of up to 27” Hg and vacuum flows up to 15.8 SCFM. These vacuum generators offer maximum holding capacity for heavy materials. Sizes are available with compressed air requirements as little as 2.3 SCFM at 80 PSIG and up to 30.8 SCFM for the largest and heaviest materials.

If you would like to talk to an Application Engineer to help you determine the best option for your application, give me a call!

Al Wooffitt
Application Engineer

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