Tools Of The Trade: The Rotameter

EXAIR’s Free Efficiency Lab

One of the free services we offer to customers here at EXAIR is our Efficiency Lab. In case you are not familiar here is a brief synopsis. Speak with an Application Engineer about your existing compressed air blowoff/point of use product and that you would like to know how much air it consumes. Fill out the brief survey and send the product you use in to our facility. Let us perform tests on calibrated test equipment to determine the force, flow, and noise level. We will then issue you a report that states what the EXAIR model would best be suited (if applicable) as well as how much compressed air you will be able to save. Order the recommendation and start saving money.

To do these evaluations, we have to have calibrated equipment that is reliable and capable of handling vast range of products we may receive in. For this, we could use a Digital Flowmeter, in some cases that is what has to be done due to large flow rates. For the majority of these though we go old school. We utilize a piece of equipment called a rotameter.

A rotameter pairs nicely with a calibrated pressure gauge as well.
The float can be seen with graduated marks for readings. The taper of the chamber is not easily seen with the naked eye.

This is a device that is designed to measure the flow rate of a fluid within a closed tube. The inside diameter of the tube is varied which causes the float within the meter to raise or lower.  They are calibrated for a specific gas at a given pressure and temperature, most are calibrated for atmospheric conditions, 14.7 psi (1.014 Bar). The meter must be mounted vertically and this is not always best suited for industrial environments.

When testing products the compressed air within the meter is pressurized which means we have to correct the reading for the given pressure, if the temperature is outside of the calibration temp then we must also perform that correction. We do this using a table provided by the manufacturer of the meter or by using the calculations shown to get exact values that may be in between the pressures in the table.

Pressure Correction Table

 

This will allow us to then multiply the Correction Factor by the meter reading and calculate our corrected flow for the point of use device at a given operating pressure and temperature.

Temperature correction table

Knowing where the values that are measured and calculated come from add validity to the reports and understanding all of the variables that go into reading like this helps to better validate the cost savings that can be seen.

In a pinch, for a field estimation, we can also use these Correction Factors and determine an approximate consumption rate of a device that has been measured at a pressure such as our cataloged 80 psig (5.5 Bar). This can often be done on the fly to help determine the flowrates currently on a system. This can be helpful when troubleshooting, giving estimated simple ROIs, and help justify results and reasons for future purchases of engineered solutions.

If you want to discuss the Efficiency Lab or any of the math behind our calculations, contact any Application Engineer, we can all help out.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Why You Should Replace Homemade Blowoffs with Engineered Solutions – ROI

 

The cheapest and easiest solution isn’t always necessarily the best. The best example I like to use to highlight this is the incandescent light bulb. They’re definitely the cheapest to buy, but over the useful life it will cost more in electricity to operate and it won’t last nearly as long as an LED light bulb. When you compare the costs of electricity as well as the lifespan of an incandescent bulb, it becomes quite clear that the initial price difference between the two will be quickly recouped over the lifetime of the LED bulb. Once it pays for itself, it doesn’t just stop saving you electricity. These savings continue to compound.

The same can be said when comparing the Super Air Knife to a commonly seen homemade alternative, drilled pipe. While it only takes a matter of minutes to drill a few holes into a section of pipe, the operating costs (electricity required to generate the compressed air) are significantly higher than that of the Super Air Knife. In addition, it’s not nearly as effective and is considered unsafe under OSHA 29 CFR 1910.242 (b) and depending on operating pressure is likely also considered dangerous due to the high sound levels as outlined in OSHA 29 CFR 1910.95(a).

Air exiting out of drilled holes in a pipe will create a turbulent airstream. This turbulence not only contributes to the high sound level but it’s ability to entrain surrounding ambient air is minuscule. The air entrainment ratio of a compressed air solution refers to the relationship between supplied compressed air and the free ambient air that is brought into the primary airstream. The higher the amplification ratio, the less compressed air necessary to complete a similar task. For a drilled pipe, the amplification ratio is generally around 3:1. With the Super Air Knife, this is dramatically increased with an amplification ratio of 40:1.

SAK vs drilled pipe

The Super Air Knife has a precisely set air gap across the full length of the knife, allowing for an efficient and quiet laminar airstream. When compared to a drilled pipe, the air consumption is dramatically reduced as is the sound level. For example, let’s take an 18” section of drilled pipe, with 1/16” diameter holes spaced out every ½”. At 80 PSIG, each hole consumes 3.8 SCFM. With a total of 37 holes, this equates to a total of 140.6 SCFM.

3.8 SCFM x 37 = 140.6 SCFM

A Super Air Knife, operated at 80 PSIG with .002” stock shim installed will consume a total of 2.9 SCFM per inch of knife. An 18” SAK would then consume just 52.2 SCFM.

2.9 SCFM x 18 = 52.2 SCFM

140.6 SCFM – 52.2 SCFM = 88.4 SCFM saved 

Replacing an 18” drilled pipe with a Super Air Knife represents a total reduction in compressed air consumption of 63%! How much does this equate to in $$$? A reasonable average of cost to generate compressed air is about $0.25/ 1000 SCF. Let’s assume just a 40hr workweek:

88.4 SCFM x 60 mins x $0.25/1000 SCF = $1.33/hr

$1.33 x 40hr workweek = $53.20 USD

$53.20 x 52 weeks/year = $2,766.40 USD in yearly savings

The 2019 list price on a Model 110018 Super Air Knife is $397.00. By replacing the homemade solution with an 18” Super Air Knife, the return on investment is just over 38 working days of an 8-hr shift. If your plant runs multiple shifts, or works on weekends, it pays for itself even quicker.

exairsak_colormedia_600x

Once the knife has paid for itself, it doesn’t just simply stop saving you money. That savings continues to compound and add to your bottom line. Don’t waste unnecessary air (and money) by using solutions that aren’t engineered to do the job in a safe and efficient manner. Reach out to an Application Engineer and get yourself an Intelligent Compressed Air Product that’s Built to Last.

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

 

Light bulb photo courtesy of Pixabay.

How Can You Benefit from EXAIR’s Efficiency Lab?

How many times have you purchased a new product and worried if it was the right choice? Well EXAIR can provide that confidence using our calibrated testing equipment to compare your current product to an EXAIR product, in our Efficiency Lab. Whenever I needed a new process or product I would spend countless hours researching how will this benefit me, my employer or my customer? Research is not only time consuming but also very costly.

EXAIR believes in their product so much that we offer an Efficiency Lab where we will test your production product and help show that our products will not only work for you, but also show that they can save money, as well as make your work environment a safer place.

EXAIR has provided performance values (force, noise, air consumption, ROI) for many of our products. We make purchasing from EXAIR fun because you know in advance that our products will meet or exceed your expectations. Further backing up our commitment with the Efficiency Lab we offer an 30 Day Unconditional Guarantee. EXAIR believes in our products and want to make your purchase a risk free process.

We can test the performance of your current product to EXAIRs Intelligent Compressed Air products for air consumption, force, noise levels… and provide a comprehensive report of our analysis, including simple ROI.  

What does our Efficiency Lab cost? EXAIR believes in our products so much, that this is a free service to our customers. Simply call and talk to one of our Application Engineers at 800.903.9247 or you can send an email to lab@exair.com or visit www.exair.com and talk on our live help. If you feel we can help with a comparison them simply send your product(s) freight prepaid to EXAIR Corporation attention to our Efficiency Lab. All trials will be on a confidential basis unless you provide permission to share.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK

Process Improvement, ROI and Safety from One Air Nozzle

Process improvement projects can be detailed, complex, expensive, and take a long time to prove their worth.  Today, I want to tell you about one that WAS NOT ANYTHING like that.

A metal stamping company used compressed air to blow their products from their dies.  They did what many do – they ran some copper tubing, and aimed it at the platen so it would properly eject the parts as they were stamped.  They KNEW it was loud, and they suspected it was inefficient as well.

After discussing the setup and seeing a picture of it (the one on the left, below,) I recommended installing a few engineered Super Air Nozzles to lower the noise levels considerably.  Boy, was I wrong.  About “a few” nozzles, that is…turns out, they only needed one Model 1122-9212 2″ Flat Super Air Nozzle with 12″ Stay Set Hose.  The copper tubes come from a manifold that already had 1/4 NPT ports – installation took a matter of minutes.  Nothing detailed, complex, or expensive about it:

This loud & inefficient copper tubing blowoff was just a compression fitting (and a Model 1122 2″ Flat Super Air Nozzle) away from being quiet and efficient.

It didn’t take much longer than that to prove its worth either: as soon as they noticed how much the noise level went down on THIS press, they ordered them for the other eighteen presses in their facility as well.

The 1/4″ copper tubes blew continuously from a pressure regulator set @60psig…the three of them theoretically consumed a total of ~80 SCFM.  The Model 1122, at 60psig supply, consumes only 17.2 SCFM.  Simple return on investment was as follows:

  • 80 SCFM was costing them $48.00 a week
    • 80 SCFM X 60 min/hr X 8 hr/day X 5 days/week X $0.25/1,000 CFM = $48.00
  • 17.2 SCFM, using the same formula, only costs $10.32 a week (I’ll let you do the math; it’s good practice.)
  • They saved $37.68 a week.  The Model 1122-9212 costs $116.00 (2020 pricing) – that means that each of them paid for themselves in just a hair over three weeks.
  • $37.68 x 50 work weeks per year = $1884.00 saved annually per nozzle
  • $1884 x 18 (the number of presses) = $33,912 saved annually 

Considering they also didn’t have to listen to those very loud open ended copper tube blowoffs, I think you’ll have to agree it made for a very good investment.  They did. The new nozzle runs at 77 decibels, a comfortable level and well below the OSHA standard [29 CFR – 1910.95(a)] for allowable noise exposure.

If you’d like to find out how EXAIR Intelligent Compressed Air Products can save you money on compressed air – and save everyone’s hearing – give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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