Line Vac Air Operated Conveyors: What to Know When Specifying

So you are thinking about using a Line Vac… Is it time to replace that ladder and bucket, and automate? There are many factors involved when deciding to use a conveyor system such as EXAIR Line Vacs. First of all let’s take a look at your product that needs conveyed. Will the integrity of your media be compromised by adding this much air to it? How heavy is it? What type of (how much) surface area does it have?

You know your media better than most. You should be able to answer most of those questions pretty easily, but what about the weight? For the weight, we work best knowing the bulk density, or pounds per cubic foot. If you do not readily know, this is easily found by finding the weight of your media in a box (or container). Then take the total cubic inches of the box (L x W x H) and divide that by 1728 (cubic inches per cubic foot), this will give you the cubic feet of that box. Then you simply divide the weight by the cubic feet, and you now have the density.

Line Vacs can convey many things.

Next we need to focus on your conveyance run. We would like to know what type of container is your product sitting in? A super sack, a hopper, a drum, a box? And where is it going? How far away is the destination hopper, dumpster, assembly station, etc.? This will help us determine the type of fitting or tools necessary to extract or release the media. How high do you need to go? How far horizontally? Our Line Vacs, are amazing, but they do have their limits. We will also need to know if there are any turns, and at what angles. Turns are many times unavoidable, but will have an adverse effect on the conveyance run as the airflow is halted and or deflected. Is there a way to minimize or eliminate the turns?

The final question is; how many pounds per minute do you need to be conveyed?

With the size, mass, and geometry of your parts, along with the vertical lift length, and the horizontal conveyance length, added to the turns and twists, you are just about ready to call one of our our application engineers for recommendations. We have some comparison materials for conveyance rates, to get you close to your actual needs. Here are some published conveyance rates as well:

There is one more part to this equation. What type and size of Line Vac will you need? EXAIR has many types of Line Vacs to choose from. As with most products, we have options that take into consideration the temperature and the abrasiveness of your product. We also have options to fit the type of conveyance hose or pipe you want to use , such as sanitary fittings, or threaded. And since we manufacture these right here in Cincinnati, OH, we can make custom Line Vacs for customers fairly quickly. We have designed and manufactured them with custom bolt on flanges, special materials or inlet sizes to name a few.

EXAIR Line Vacs: For bulk material conveyance through lines from 3/8″ to 6″, in aluminum, 303SS, 316SS, or abrasion resistant hardened alloy, available from stock with the widest variety of connections in the industry.

Please do not hesitate to call. We will be happy to help you with any technical questions about our products.

Application Engineer

Brian Wages

EXAIR Corporation
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Yellow Ladder pic from OpenClipart-Vectors / 27385 & Bucket Pic from Jazella / 704 images on a Pixabay License

“Free” Ambient Air Entrainment w/ EXAIR’s Super Air Amplifiers

When working with a cooling application, many customers will immediately look to the Vortex Tube and Spot Cooling product lines. While this may be the best solution for some applications, cold air is not always the best method that we have available for cooling. EXAIR’s Super Air Amplifiers are very effective at reducing the temperature of a part without requiring cold air. The Super Air Amplifiers get their name due to their ability to entrain ambient air and “amplify” the supplied compressed air. You’ll often see us referring to the air amplification ratios achieved with our products. This is a ratio of the supplied compressed air relative to the entrained “free” air that comes from the ambient environment.

Due to their ability to entrain large amounts of ambient air, we can move a high volume of air across the surface of the part and quickly lower the temperature. I like to compare this to blowing on a hot cup of coffee just as it’s been brewed. The temperature of the air coming from your mouth is around 98.6°F, the same as your body temperature. Coffee can be as hot as 185°F when fresh. Due to the temperature differential between your breath and the hot coffee, we’re able to achieve a reasonable amount of cooling just by simply blowing across the surface. Typically, when the target temperature of the part or material needs to be around ambient temperature or higher; the best solution for cooling is going to be a Super Air Amplifier.

EXAIR’s Super Air Amplifiers achieve air amplification ratios ranging from 12:1 on our smallest units and up to 25:1 for our 4” and 8” models. EXAIR’s Super Air Amplifiers utilize a patented shim design to maintain critical positioning of component parts. This allows a precise amount of compressed air to be released at exact intervals toward the center of the Super Air Amplifier. This creates a constant, high velocity outlet flow across the entire cross-sectional area. Free, ambient air is entrained through the unit, resulting in high amplification ratios. The balanced outlet airflow minimizes wind shear to produce sound levels far lower than other similar air movers.

Super Air Amplifiers are supplied with a .003” thick shim that is ideal for most applications. Flow and force can be increased by replacing the shim with a thicker .006” or .009” shim. The flow of air is also controlled by adjusting the input pressure supplied to the amplifier. Higher pressures increase both the force and flow, while lower pressures decrease both force and flow. All Super Air Amplifiers are available in kits that come with a shim set as well as a suitably sized pressure regulator and auto-drain filter.

EXAIR has a solution for you if you need to move A LOT of air. Reach out to an Application Engineer today if you have an application that you believe could be served with a low-cost, simple solution!

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

Air & Water DO Mix – Why That’s A Problem for Compressed Air Systems

Wherever you go, humidity – and its effects – are an inescapable fact of life. Low humidity areas (I’m looking at you, American Southwest) make for a “dry heat” in the summer that many prefer to the wet & muggy conditions that areas with higher humidity (like much of the rest of the United States) encounter during the “dog days” of summer.

Regardless of human comfort level issues, all atmospheric air contains water vapor in some finite proportion…in fact, next to nitrogen and oxygen, it makes up a bigger percentage of our air’s makeup than the next eleven trace gases combined:

Reference: CRC Handbook of Chemistry and Physics, edited by David R. Lide, 1997.

And, because warmer air is capable of holding higher moisture concentrations (a 20°F rise in temperature doubles the potential for holding moisture), chances are good that it’ll become a bigger problem for your compressed air system in the summertime. So…how BAD of a problem is it? Let’s do some math. Consider a nice, typical summer day in the midwest, when it’s 80°F outside, with a relative humidity of 75% and we’ll use the data from the tables below to calculate how much water collects in the compressed air system:

Source: Compressed Air & Gas Institute Handbook, Chapter 3
Source: Compressed Air & Gas Institute Handbook, Chapter 3

Let’s assume:

  • An industrial air compressor is making compressed air at 100psig, and at a discharge temperature of 100°F.
  • The demand on the compressed air system (all the pneumatic loads it services) is 500 SCFM.

Table 3.3 tells us that, at 80°F and 75% RH, the air the compressor is pulling in has 0.1521 gallons per 1,000 cubic feet.

Table 3.4, tells us that, at 100°F and 100psig, the compressor is discharging air with a moisture content of 0.0478 gallons per 1,000 Standard Cubic Feet.

The difference in these two values is the amount of water that will condense in the receiver for every 1,000 SCF that passes through, or 0.1521-0.0478=0.1043 gallons. Since the demand (e.g., the air flow rate out of the receiver) is 500 SCFM, that’s:

500 SCFM X 60 min/hr X 8 hr/shift X 0.1043 gallons/1,000 SCF = 25 gallons of condensate

That’s 25 gallons that has to be drained from the receiver tank over the course of every eight hours, so a properly operating condensate drain is crucial. There are a few types to choose from, and the appropriate one is oftentimes included by the air compressor supplier.

So, you’ve got a condensate drain on your compressor’s receiver, and it’s working properly. Crisis averted, right? Well, not so fast…that 100°F compressed air is very likely going to cool down as it flows through the distribution header. Remember all that moisture that the hot air holds? Assuming the compressed air cools to 70°F in the header (a reasonable assumption in most industrial settings), a bunch of it is going to condense, and make its way to your air tools, cylinders, blow off devices, etc., which can cause a host of problems.

Reversible Drum Vacs have tight passages where contaminants (like pipe rust) can accumulate and hamper performance. Fortunately, they are designed to be easy to clean and returned to peak performance.

And…I trust you saw this coming…we’re going to calculate just how much condensation we have to worry about. Using table 3.4 again, we see that the header’s air (at 100psig & 70°F) can only hold 0.0182 gallons per 1,000 SCF. So, after cooling down from 100°F (where the air holds 0.0478 gallons per 1,000 SCF) to 70°F, that means 0.0296 gallons per 1,000 SCF will condense. So:

500 SCFM X 60 min/hr X 8 hr/shift X 0.0296 gal/1,000 SCF = 7.1 gallons of condensate

Qualified installers will have sloped the piping away from the compressor, with drip legs strategically placed at low points, so that condensate can drain, collect, and be disposed of…oftentimes via similar devices to the condensate drains you’ll find on the compressor’s main receiver. Good engineering practice, of course, dictates point-of-use filtration – EXAIR Automatic Drain Filter Separators, with 5-micron particulate elements, and centrifugal elements for moisture removal, are also essential to prevent water problems for your compressed air operated products.

Good engineering practice calls for point of use filtration and moisture removal, such as that provided by EXAIR Filter Separators.

EXAIR Corporation remains dedicated to helping you get the most out of your compressed air system. If you have questions, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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EXAIR’s New Cabinet Cooler® System Calculator

For the longest time we have been using this form on EXAIR.com to get the information we needed to manually calculate the internal and external heat loads and ultimately make a recommendation on which Cabinet Cooler System would be best for that application! Typically it would take thirty minuets to an hour to get a email back from a application Engineer!

While the manual Cabinet Cooler Sizing Guide worked great (and we will still reply within 24 hours), we have been racking our heads over here to better that process and get you a solution faster than ever! Now you type in your information and you have a recommendation and a link to that product on the website where you can learn more or place an order! So you can go from form to order in less than 5 Minuets!!!! Check it Out HERE!!

By providing certain information like size of the enclosure, NEMA rating needed, and environmental conditions, this new calculator will sort through our large selection of ready-to-ship Cabinet Cooler® Systems and provide instant feedback on the best model number for any applicable electrical enclosure.  Taking the guess work out of the equation, EXAIR’s Calculator ensures the customer that they can be confident in selecting the correct product for their unique specifications. You can even Print the form for your records!

Cabinet Cooler Calculator

            EXAIR’s complete line of Cabinet Cooler systems include 120V AC, 240V AC and 24V DC thermostat voltage, continuous operation, type 316 stainless steel and high temperature models – all of which are selectable with the new calculator. Find this new tool on the website EXAIR.com, in the Knowledge Base Calculators, along with many other resources, such as the CAD Library and Application Database, which also help customers choose a perfect solution. Cabinet Cooler systems start at $534. https://www.exair.com/knowledgebase/calculator-library/cabinet-cooler-system-calculator.html

Jordan Shouse
Application Engineer

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