Tag: efficiency

What’s So Awful About A Drilled Pipe For A Conveyor Blowoff?

Published on by Russ BowmanLeave a comment

A technician from a company that performs comprehensive audits of compressed air systems called me with a sad, sad story. A client had just installed a brand-new state-of-the-art rotary scroll compressor with a variable speed drive…they were going all-out on efficiency, which is great. During the technician’s walk-through, however, he noticed a blowoff on a conveyor belt — they actually heard it before they could see it — a black iron pipe with a series of holes drilled along the length, plumbed with compressed air being supplied, unregulated, from a 100psig header.

The pipe was 18″ long and had 30 holes, 1/8″ diameter each, drilled along the length. From the table below, we can presume that this drilled pipe was consuming as much as 475.8 SCFM:

I say “as much as 475.8 SCFM” because the technician noted the holes were simply drilled through, they weren’t rounded, so I calculated the flow from a 1/8″ orifice at 100psig (26.0 CFM) with a 0.61 multiplier for sharp edges orifices. Also, the inlet pressure of the drilled pipe is not known. With a 1″ pipe supplying it, the flow could be limited to around 350 SCFM, due to line loss in the pipe.

The technician first asked about installing Air Nozzles in the drilled pipe. That’d mean drilling those holes out and tapping them individually. This COULD be done, and the drilled pipe could be fitted with 30 Model 1110-PEEK Nano Super Air Nozzles, with an air consumption of 8.3 SCFM @80psig each, for a total of 249 SCFM. That’s a significant reduction, but also a lot of work on the drilled pipe. I recommended replacing it entirely with a Super Air Knife.

A Model 110018 18″ Aluminum Super Air Knife consumes only 52.2 SCFM @80psig — almost an order of magnitude reduction! Let’s do the math on the costs:

First, the drilled pipe: Let’s give all the benefit of the doubt here and assume that the line loss had indeed limited the air consumption to 350 SCFM. Operating 8 hours a day, 5 days a week, 52 weeks a year, and using the US Department of Energy’s estimate that compressed air costs $0.25 per 1,000 Standard Cubic Feet used, the annual operating cost of the drilled pipe was $10,920.00:

350 SCFM X 60 min/hr X 8 hrs/day X 5 days/week X 52 weeks/year X $0.25/1,000 SCF = $10,920.00

Drilling & tapping those holes for EXAIR Nano Super Air Nozzles (8.3 SCFM ea X 30 = 249 SCFM total) would result in an annual operating cost of $7,768.80:

249 SCFM X 60 min/hr X 8 hrs/day X 5 days/week X 52 weeks/year X $0.25/1,000 SCF = $7,768.80

Replacing the drilled pipe with an EXAIR 18″ Super Air Knife (52.2 SCFM) drops the annual operating cost even further, to $1,628.64:

52.2 SCFM X 60 min/hr X 8 hrs/day X 5 days/week X 52 weeks/year X $0.25/1,000 SCF = $1,628.64

To put that further into perspective, the 2025 List Price for an 18″ Aluminum Super Air Knife is $533.00. It costs almost $9,300.00 per year LESS to operate than the drilled pipe. That means the Air Knife will have paid for itself in operating costs in just under 21 days.

To put that even FURTHER into perspective, the ~300 SCFM reduction in compressed air consumption is approximately 75HP worth of a typical industrial air compressor load. It’s not uncommon for a mid-to-large sized company to have more than one air compressor, and 50HP is a common size for a backup compressor. If that was the case in the facility that my technician caller was auditing, he’d be letting them know that this $533.00 investment that’s going to save them over $9,000.00 a year is ALSO going to allow them to shut down one of their air compressors. Completely.

So, THAT’S what’s so awful about a drilled pipe. If you have any in your facility, we should talk.

Russ Bowman, CCASS

Application Engineer
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Efficient Compressed Air System Design with EasyCAS – Powered by Direktin

Published on by Tyler DanielLeave a comment

When it comes to designing an efficient compressed air system, we all know the details matter. From nozzle selection and pipe sizing to pressure drops and force calculation, it’s easy for small oversights to add up to big inefficiencies. That’s why I’m excited to share some news that will help make designing with EXAIR products easier than ever.

EXAIR has officially partnered with DirektIn, the company behind EasyCAS, a powerful design and simulation tool built specifically for industrial compressed air systems. What does that mean for you? It means that many of your favorite EXAIR products: Super Air Knives, Safety Air Guns, Air Nozzles, Air Amplifiers, and more, are now available directly in the software’s component library.

EasyCAS is a comprehensive tool designed to empower engineers, facilities, and suppliers to design, size, simulate, and validate the design and efficiency of a compressed air system with data-driven guidance. Not only can it help you create and maintain a compressed air system from scratch, but uses data and monitoring to pinpoint areas of inefficiency and highlight solutions or products to address the problems. 

EasyCAS offers a great deal of other advantages as well, including:

  • Simulating pressure drops
  • Highlighting helpful components
  • Prevent downtime by identifying problems
  • Calculating air savings and carbon credits
  • Validate performance of your current system

and much more!

You can define line routing, pressure settings, and consumption points, then drop in components like EXAIR Super Air Knives or Nozzles and see how they affect overall system performance in real time.

One of the things I love most about EasyCAS is how intuitive it is. You don’t need to be a CAD expert or software engineer to use it! Just drag, drop, and adjust. Want to compare how much air a homemade drilled pipe uses versus a properly sized Super Air Knife? You can do that. Curious about how much pressure drop you’ll see if multiple Air Nozzles are fed from a single line? EasyCAS has you covered. It’s a great way to visualize pressure loss, flow distribution, and performance impact before anything ever gets installed.

EXAIR is proud to be the only supplier of engineered point-of-use compressed air products currently integrated into the EasyCAS library. That means if you’re designing with EXAIR, you’re designing with confidence.

Visit direktin.com to learn more and for a limited time, you can use code “EXAIR2025” to get 10% off a yearly subscription! EasyCAS could be the answer to revolutionizing your processes.

Tyler Daniel, CCASS

Application Engineer/Intl Trade

E-mail: TylerDaniel@EXAIR.com

X: @EXAIR_TD

Compressed Air In The Wild

Published on by Brian FarnoLeave a comment

Over the past weekend, I had the honor of visiting a local MakerSpace. These types of places are what my dreams are made of. The one we toured had a full metal and woodworking shop as well as a separate area for 3D printing, sewing, standard printing, electronics, and even laser engraving/cutting. Every workstation has an electrical drop and a compressed air drop coming from the ceiling as the area can be used for any number of projects.

Handheld air guns are something that you can find in nearly any and all manufacturing facilities that have compressed air within them. Suppose they are not at every operator station because the machines don’t require compressed air. In that case, they are generally found at the very least within the maintenance department, where they continually keep the facility functioning and may be the only ones in the facility with compressed air.

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Don’t let this happen to your air gun…use an EXAIR Precision Safety Air Gun with a quiet, efficient Super Air Nozzle instead.

Handheld blowguns like the one shown above are easily overlooked when it comes to operator safety and energy savings. Often, the cheapest gun possible is also the most costly regarding ownership and operation. These are just a few of the reasons EXAIR designed the VariBlast Precision Safety Air Gun.

The ergonomic design fits well in any sized hand and the long trigger makes for easy pull and variation in the amount of air being used. The integrated loop allows the tool to easily hang on a tether or hook near an operator station, while the optional Chip Shield adds additional protection for the operator and can be adjusted to any location along the extension. Effective chip guarding is a portion of the OSHA standard for dead-end pressure. Lastly, the extension pipe is offered in three different lengths: 6″, 12″, or 20″ overall length. Each one of these components is also field replaceable in the event one becomes damaged. That means it’s not disposable like the other guns on the market.

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Three different Super Air Nozzle models are available at the end of the extension in two separate materials. You can purchase the Atto, Pico, or Nano Super Air Nozzle in either stainless steel or PEEK thermoplastic for more sensitive applications. These nozzles coupled with our engineered valve design permit the user to vary the amount of air coming out of the gun by pulling the trigger to a higher flow or pulling it slightly and letting less volume of air through.

If you want to discuss whether your current air gun meets or exceeds OSHA standards and how much air it may use versus what an EXAIR VariBlast Precision can do for you, please contact an Application Engineer today.

Brian Farno, MBA – CCASS Application Engineer

BrianFarno@EXAIR.com
@EXAIR_BF

Intelligent Compressed Air: Air Compressor Isentropic Efficiency

Published on by Russ BowmanLeave a comment

If you’re reading the EXAIR blog, odds are you’re interested in getting the most out of your compressed air system. While using engineered compressed air products is certainly one of the best ways to do that (see our Six Steps To Optimizing Your Compressed Air System), there are some things you can look at on the supply side as well. One such metric – and a key one, at that – is isentropic efficiency.

In a nutshell, isentropic efficiency is a measure of how well an air compressor converts the electrical energy it consumes into compressed air. The basic formula is a ratio between the compressor’s actual performance to that of an ideal compression process. Mathematically, it’s expressed as:

Now, as long as air compressors have moving parts, the actual energy consumed will always be higher than the amount of energy required for an ideal process. That’s because the ideal process ignores inescapable losses due to friction between – and inertia of – moving parts, electrical losses (motor efficiency), pressure drops, and heat of compression. So, like any other machine or engine, you’ll never get 100% efficiency.

It’s still a great idea to look for the highest efficiency. So great, in fact, that the U.S. Department of Energy, just this month, began efficiency regulation for oil-flooded rotary air compressors, meaning these compressors will have to meet minimum standards of isentropic efficiency. Specific Power used to be the standard by which an air compressor’s efficiency would be evaluated. It’s the ratio of power consumption to the amount of compressed air produced, normally expressed as kW/100CFM. That doesn’t take the compressor discharge pressure into consideration, which does indeed affect the power needed to generate a given amount of compressed air. We know that a 2psi pressure change will result in a 1% change in power consumption. So, if one manufacturer reports the Specific Power as kilowatts per 100 CFM @100psig, and another reports it as kilowatts per 100 CFM @140psig, that 40psi difference means a 20% variance.

Now, that doesn’t mean we stop using Specific Power – it’s one of the two variables in the isentropic efficiency equation. The other being, of course, the discharge operating pressure:

Where:

  • 16.52 and 0.2857 are constants
  • p2 is the discharge operating pressure (psig)
  • 14.5 is atmospheric pressure (psi) – this corrects gauge pressure to absolute pressure
  • P2 is Specific Power

The Compressed Air & Gas Institute (CAGI) publishes data sheets that are analogous to the fuel efficiency stickers on new car windows. Here’s a sample of one:

And, using the isentropic efficiency formula:

We get an isentropic efficiency of 86.50% (close enough to the CAGI Data Sheet’s 86.47%; likely due to a significant figure discrepancy in the calculations), which is pretty good. The highest published isentropic efficiency is about 92%. At EXAIR, our mission is to help you get the most out of our products and your compressed air system. If you have questions, we’ve got answers – give me a call.

Russ Bowman, CCASS

Application Engineer
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