## ROI: Super Air Knife vs. Drilled Pipe

Return on Investment, or ROI, is the ratio of profit over total investment.  Many people use it to check investment stocks, financial markets, capital equipment, etc.  It is a quantitative way in determining the validity for an investment or project.   You can use this ROI value to give a measurable rate in looking at your investment, no matter how big or small.  In this blog, I will compare the ROI between an EXAIR Super Air Knife to a home-made drilled pipe.  Let’s start by looking at Equation 1 to calculate the Return on Investment.  For a positive ROI value, the project will pay for itself in less than one year.  Any negative values would represent a high-risk investment.

Equation 1:  ROI = (Total Annual Savings – Total Project Cost) / Total Project Cost * 100

The Total Project Cost is the cost of the product with the labor to install.  In our example, we will use a 36” (914mm) blow-off device to cover the width of a conveyor.  One device will be an inexpensive drilled pipe and the other will be a high-efficiency EXAIR Super Air Knife.  The drilled pipe had (72) 1/16” (1.6mm) diameter holes spaced ½” (13mm) apart.  EXAIR manufactures the model 110036 36” Aluminum Super Air Knife with a .002” (.05mm) shim along the entire length.  The model 110036 has a retail price of \$802.00 each.  The cost of the home-made drilled pipe was around \$70.00 for material and labor.  What a difference in price!  It seems like the ROI should be in the negative, but is it?

Let’s continue on with the Return on Investment.  The amount of time required to install the Super Air Knife across the conveyor only took a maintenance staff about one hour to mount.  The labor rate that I will use in this example is \$80.00 per hour (you can change this to your current labor rate).  The labor cost to install the knife is \$80.00.   The Total Project Cost can be calculated as follows: \$802 + \$80.00 = \$882.00.  The next part of the equation, Total Annual Savings, is a bit more in-depth, but the calculation is below.

To calculate the Total Annual Savings, the amount of compressed air used by the drilled pipe is around 261 SCFM (7,389 SLPM) at 60 PSIG (4.1 Bar).  The model 110036 Super Air Knife has an air consumption of 82.8 SCFM (2,344 SLPM) at 60 PSIG (4.1 Bar).  With an electrical rate of \$0.08 per Kilowatt-hour, the electrical cost is near \$0.25 per 1000 standard cubic feet or compressed air, or \$0.25/1000SCF.  To calculate an annual savings, let’s use a blow-off operation of 8 hours/day for 250 days a year.   Replacing the drilled pipe with the model 110036 Super Air Knife, it will save you (261 SCFM – 82.8 SCFM) = 178.2 SCFM of compressed air.  To put this into a monetary value, the annual savings will be 178.2 SCFM *\$0.25/1000SCF * 60 Min/hr * 8hr/day * 250 day/yr = \$5,346.00 per year.

With the Total Annual Cost and the Project Cost known, we can insert these values into Equation 1 to calculate the ROI:

ROI = (Total annual savings – Total Project Cost) / Project Cost * 100

ROI = (\$5,346.00 – \$882.00) / \$882.00 * 100

ROI = 506%

With a percentage value that high, we are looking at a payback period of only 40 days.  You may look at the initial cost and be discouraged; but in a little over a month, the model 110036 will have paid for itself.  And after using it for one year, it will save your company \$5,346.00.

In my experience, a loud blowing noise from your equipment is generally coming from an inefficient and safety-concerned product.  With these “cheap” ways to blow compressed air, it will cost your company a lot of money to use as shown in the example above.  EXAIR has an Air Savings Calculator on our website to calculate the savings by replacing your inefficient blow-off devices. And, if you would like to team up with EXAIR to find ways to increase savings, improve productivity, and promote safety, you can contact an Application Engineer.  We can help you get started by defining your Return on Investment with EXAIR products.

John Ball
Application Engineer
Email: johnball@exair.com

## Engineered Compressed Air Products = Less Noise & Money Saved

Everyone dislikes loud noises for the most part. Here in Ohio we just got done surviving the constant buzz and swarming of cicadas. We all deal with noise on a daily basis, some of it enjoyable and some of it not so much. Noise is an inescapable fact of life and all we can do is try to reduce noise level to save our sanity. But, did you know that cutting down on the noise produced by compressed air blow offs can actually save you money? Your loud homemade blow off system is not only way too loud, but it is most likely also costing you more money than you need to spend.

EXAIR’s engineered compressed air products are designed to operate quietly and efficiently. The reduction in noise they produce is only one of the benefits – another is the reduction in money by reducing compressed air use.

But how does one calculate out the ROI? It is very simple to calculate out your potential savings of using one of EXAIR’s Intelligent Engineered Compressed Air Products. If you would rather not do the calculations out yourself then we can do it for you by sending the item in question to our Efficiency Lab Testing. The Efficiency Lab Testing is a free service that we offer to show you the possible savings by switching to one of our products.

The following is a typical ROI preformed and replaced with a corresponding EXAIR Super Air Nozzle:

• ¼” drilled pipe with (3) 3/32” Holes which uses 9.4 SCFM per hole at 80 psig (denoted as DP)
• A Model 110003 3” Super Air Knife can be used to replace and only uses 8.7 SCFM at 80 psig (denoted below as SAK)

Calculation:

(DP air consumption) * (60 min/hr) * (8 hr/day) * (5 days/week) * (52 weeks/year) = SCF used per year for Copper Pipe

(28.2) * (60) * (8) * (5) * (52) = 3,519,360 SCF

(SAK air consumption) * (60 min/hr) * (8 hr/day) * (5 days/week) * (52 weeks/year) = SCF used per year for EXAIR Product

(8.7) * (60) * (8) * (5) * (52) = 1,085,760 SCF

Air Savings:

SCF used per year for DP – SCF used per year for SAK = SCF Savings

3,519,360 SCF – 1,085,760 SCF = 2,433,600 SCF in savings

If you know the facilities cost to generate 1,000 SCF of compressed air you can calculate out how much this will cost you would save. If not, you can us \$0.25 to generate 1,000 SCF which is the value used by the U.S. Department of Energy to estimate costs.

Yearly Savings:

(SCF Saved) * (Cost / 1000 SCF) = Yearly Savings

(2,433,600 SCF) * (\$0.25 */ 1000 SCF) = \$608.40 annual Savings

With the simple investment of \$216 (as of date published) you can calculate out the time it will take to pay off the unit.

Time Until payoff:

(Yearly Savings) / (5 days/week * 52 weeks/year) = Daily Savings

(\$608.40/year) / (5 days/week * 52 weeks/year) = \$2.34 per day

(Cost of EXAIR Unit) / (Daily Savings) = Days until unit has been paid off

(\$216) / (\$2.34/day) = 92.3 days

As you can see it doesn’t take long for the air knife to pay for itself. You also get better overall performance as the Super Air Knife will provide a solid curtain of air. In the end you get to breathe a sigh of relief as no more jump scares and a loud hiss when you turn your air on. Who doesn’t like to save a little money and sanity, especially in these crazy times?

If you have any questions or want more information on EXAIR’s Air Knifes or like products. Give us a call, we have a team of application engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
Visit us on the Web

## Compressed Air Vs. Blower Air Knife & Other Alternatives

An often debated subject is whether it makes more sense to use a compressed air powered Air Knife or a blower powered Air Knife.  Initially, one might think that the blower option might be a more economical solution due to its slightly lower electrical consumption when compared to an air compressor.  However, a blower powered Air Knife is an expensive capital expenditure that requires frequent downtime, costly maintenance of filters, belts, bearings and electricity!  They also take up a lot of space and can produce sound levels that exceed OSHA noise level requirements.  EXAIR’s Super Air Knife even when operated at 80 PSIG (5.5 BAR), is surprisingly quiet at 69 dBA!

Another drawback for the blower powered Air Knives is the air volume and velocity can be difficult to control since these are adjusted mechanically.

Some other important maintenance considerations are:

• Filters must be replaced every 1 – 3 months.
• Belts must be replaced every 3 – 6 months.
• Blower bearings wear out quickly due to the high rpm requirements.
• The Seals wear and can allow dirt and moisture to enter, couple that with high temperature environments and the bearing life will be reduced.
• Blowers typically add heat to the air flow, making it unsuitable for cooling applications.

In contrast the award winning and highly efficient EXAIR Super Air Knife represents our latest generation of innovation that dramatically reduces compressed air usage and noise, with no moving parts!

The EXAIR Super Air Knife is a great way to clean, dry or cool parts because they deliver a uniform sheet of laminar air flow across it’s entire length with force that can range from a gentle breeze to extreme hard-fitting force!

EXAIR Super Air Knives highly engineered design entrains ambient air at a ratio of 40:1.  This simply means that for every (1) part of compressed air supplied (40) parts of ambient air are pulled into the compressed air stream exiting the nozzle.

1). Compressed air flows into the plenum of the Super Air Knife.  The flow is directed to a precision slotted orifice.

2). As the air-flow exits the air gap it follows a flat surface that directs the air flow in a perfectly straight line.  This creates a uniform sheet of air across the entire length of the Super Air Knife.

3).  Velocity loss is minimized and force is maximized as the room air is entrained into the primary air-stream at a 40:1 ratio.  This all results in a well defined sheet of laminar air-flow with hard hitting force.

Advantages of the Super Air Knife

• Very Quiet, typically 69 dBA for most applications
• Minimal Compressed air consumption
• 40:1 air amplification
• Uniform air flow across the entire length
• Force and flow are variable
• No moving parts – therefore maintenance free
• Easy mounting – compressed air inlets are conveniently located on each end and the bottom
• Compact design, rugged design and very easy to install
• Recessed hardware
• Stock lengths up to 108″ in Aluminum (max temperature of 180°F/82°C), 303SS or 316SS (max temperature 800°F/427°C)
• PVDF is available up to 54″ long for superior corrosion resistance (max temperature 275°F/135°C)

EXAIR’s Super Air Knife is also a great replacement for other commonly used, but highly inefficient and noisy compressed air operated devices.

As an example, two commonly used blow-offs are the drilled pipe and flat air nozzles installed into a pipe.  EXAIR performed a head to head test employing the EXAIR Super Air Knife, Blower Powered Air Knife, Drilled Pipe & Plastic Flat Nozzles mounted in a pipe.

Below are the results of that test from a very common application, blowing water off bottles.  As shown in the First Year Cost Column it becomes clear that the true cost of ownership needs to be considered.  Many plants are surprised at how efficient the EXAIR Super Air Knife is compared to other alternatives.

Another important consideration is how effective these other blow-off methods are.  The drilled pipe and flat air nozzles have “dead spots” where the air flow is non existent leaving some of your product wet and/or dirty.

When you are looking for expert advice on safe, quiet and efficient point of use compressed air products give us a call.   We would enjoy hearing from you.

Steve Harrison
Application Engineer
Send me an email
Find us on the Web

## The Super Air Knife Vs. a Homemade Drilled Pipe Solution

A drilled pipe has been used for many years to blow compressed air across a span for cleaning, cooling, and drying.  They are a simple tool that was created from spare parts and many holes.  The cost to make this type of product is not expensive, but to use this product in your application is very expensive.  Similarly, an incandescent lightbulb is inexpensive to purchase, but it will cost you much more in electricity than a LED light bulb.  Since 1983, EXAIR has been innovating safe and efficient products to be used in compressed air systems.  In this blog, I will compare the drilled pipe with the Super Air Knife.

Even though you can find the components relatively easily to design your own drilled pipe, this blow-off design is very costly and stressful to your compressed air system.  Typically, the holes along the pipe are in a row next to each other.  As the airstream leaves from each hole, it will hit the airstream from the one next to it.  This will cause turbulent air flows which has inconsistent forces and loud noises.  Also, with turbulent air flows, the ability to entrain the surrounding ambient air is very small.  We call this the amplification ratio.  The higher the amplification ratio, the more efficient the blow-off device is.  For a drilled pipe, the amplification ratio is near 3:1 (3 parts ambient air to 1 part compressed air).

A colleague, Brian Bergmann, wrote a blog about the amplification ratio of the EXAIR Super Air Knife.  (Read it HERE.)  This blog demonstrates how EXAIR was able to engineer an efficient way to blow air across a span.  The unique design of the Super Air Knife creates an amplification ratio of 40:1 which is the highest in the market.   Unlike the drilled pipe, the gap opening runs along the entire knife for precise blowing.  This engineered gap allows for laminar air flow which has a low noise level, a consistent blowing force, and maximum amplification ratio.  With these benefits, the Super Air Knife can reduce the amount of compressed air required, which will save you money and save your compressed air system.

In comparing the drilled pipe to the Super Air Knife, I will relate both products in a simple cooling application.   Thermodynamics expresses the basics of cooling with an air temperature and an air mass.  Since both products are represented in the same application, the air temperature will be the same.   Thus, the comparison will be with the amount of air mass.  In this example, the customer did some calculations, and they needed 450 Lbs. of air to cool the product to the desired temperature.  At standard conditions, air has a density of 0.0749 lbs/ft3.  To convert to a volume of air, we will divide the weight by the density:

450 lbs. / (0.0749 lbs./ft3) = 6,008 ft3 of air

To meet this requirement, reference Table 1 below.  It shows the volume of air required by your compressed air system to meet this demand.  As you can see, your compressor has to work 13X harder to cool the same product when using a drilled pipe.  Just like the LED light bulbs, the Super Air Knife has more efficiency, more innovation, and uses less compressed air.  In turn, the Super Air Knife will save you a lot of money in electrical costs.  If you would like to see how much the Super Air Knife can save compared to the drilled pipe, we have that information in this blog.  (Read it HERE.)  For my reference, it will reduce the stress of your compressed air system.

if you would like to compare any of your current blow-off devices with an innovative EXAIR product, you can contact an Application Engineer.  We can do an Efficiency Lab to shine an LED light on saving energy and money with your compressed air.

John Ball
Application Engineer
Email: johnball@exair.com