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

Watch EXAIR Webinars On-Demand

That’s right, just like your local cable or satellite TV provider, EXAIR offers On-Demand content that can be streamed and used for training, education, help with cost justification, or improve awareness around compressed air costs and safety.

The best part about this content is that you don’t have to pay for it, simply register on our website (where your information is not shared) and go to the Webinars section of our Knowledge Base.  Then gain access to the library of five webinars that have all been broadcast around compressed air safety, efficiency, and optimization. – Webinars On-Deman

The current On-Demand offering is listed below:

Intelligent Compressed Air Solutions for OSHA Compliance
Intelligent Solutions for Electrical Enclosure Cooling
Optimize Your Compressed Air System in 6 Simple Steps
Simple Steps for Big Savings
Understanding Static Electricity

The most recent webinar we created is currently only On-Demand for registered attendees and will soon be added to the Knowledge Base library.  If you did not get to see it live, the content was extremely helpful for anyone that works within a facility that uses compressed air.  Use This Not That – 4 Common Ways To Save Compressed Air In Your Plant, keep an eye out for the release date in our On-Demand section.

If you would like to discuss any of the webinar topics further, please feel free to reach out to an Application Engineer.

Brian Farno
Application Engineer

OSHA Safety, Efficiency, and Flexibility from Engineered Compressed Air Nozzles

Throughout my years here at EXAIR as well as my years in the metal cutting industry, one of the most common quick fixes I see in production environments for compressed air blowoffs in a process is an open copper pipe that is contorted into a position, pinched at the end, and more often than not kinked from repositioning. I call this a quick fix because it does blow air, more often than not it will get production up and running, but it does not meet or exceed OSHA standards for safety and is an inefficient use of compressed air. [OSHA Standards 29 CFR 1910.242(b) and 29 CFR 1910.95(a)]

EXAIR Super Air Nozzles that are easy replacements for 1/8″ and 1/4″ Copper pipe.

The first engineered solution I could offer to prevent any costly OSHA fines and to lower the ambient noise level caused by these blowoffs is to implement an EXAIR Engineered Air Nozzle. We offer a wide variety of nozzles ranging from a 4mm thread up to a 1-1/4″ NPT thread. With this wide range comes a wide variety of forces and flows as well.

Today, I would like to focus on the common sizes of copper blowoffs which are 1/8″ and 1/4″. To simply adapt a nozzle to copper line a compression fitting can be easily sourced, often from EXAIR, and convert the copper tubing in place to an NPT threaded outlet for easy installation of an EXAIR nozzle. More often than not a compression fitting is how the copper tubing is tied into the machine’s compressed air system.

We have a total of 37 engineered air nozzles from stock that will easily fit a compression fitting which goes to a 1/8″ NPT or 1/4″ NPT thread. Several of these are also adjustable through a gap adjustment or a patented shim adjustment to vary the force and flow out of the nozzle from a forceful blast to a gentle breeze in order to me your application needs. What if you want to eliminate the copper line and compressions fittings?

EXAIR offers a replacement option for the ever-common copper tube that is more robust and does not require a tool to be properly repositioned. We currently offer twenty-four different models of our Stay Set Hoses that can be easily connected to any of the nozzles mentioned above. The lengths that are available are 6″ (152mm), 12″ (305mm), 18″ (457mm), 24″ (610mm), 30″ (762mm) and 36″ (914mm).

These lengths are available with two separate connection options. 1/4″ MNPT x 1/4″ MNPT or 1/4″ MNPT x 1/8″ FNPT. The Stay Set Hoses can easily be bent by hand into position for a precise placement of the air pattern from the engineered nozzle attached to it. This permits operators a tool free adjustment for fast and reliable location to keep production up and running. They can also be paired with Magnetic Bases.

EXAIR Magnetic Bases are available in single outlet or dual outlet configurations. Both include a 100 lb. pull magnet that will hold tight to any ferrous metal surface for secure mounting, as well as a quick 1/4 turn miniature valve on each outlet. This permits independent customization of the force our of each output for the dual outlet mag base. Each magnetic base offers a 1/4″ FNPT inlet port and outlet port. We offer these with any of combination of the Stay Set Hoses mentioned above as well as any of the Super Air Nozzles mentioned above.

Mag Bases come with one or two outlets. Stay Set Hoses come in lengths from 6″ to 36″.

The Super Air Nozzles, Stay Set Hoses, and Magnetic Bases can be easily combined before they ship to your facility to make a complete blowoff station that is easily installed and adjusted to fit any of the needs your process may have for a point of use blowoff. If you want help determining how much compressed air you would save by replacing the open pipe blowoffs with an engineered solution like a Stay Set Magnetic Base Blowoff System please contact myself or any Application Engineer here at EXAIR.

Brian Farno
Application Engineer


Engineered Compressed Air Nozzles and Utility Rebates

When EXAIR started to manufacture compressed air products, we created a culture in making high quality products that are safe, effective, and efficient.  Being leaders in this industry, we created a program, the Efficiency Lab, to compare blow-off devices with EXAIR products in noise levels, flow requirements, and force measurements.  With calibrated test equipment, we compare the data in a qualified report to share with our customers.  This information can be helpful to determine the total amount of air savings and safety improvements that EXAIR products can offer.

Flat SANs 1in
Zinc Aluminum models are suitable for general purpose blow off (left) and 316SS models are specified for food/pharma and high heat applications.

In conjunction with the Efficiency Lab, we created a Cost Savings Calculator.  It is a quick way to view payback periods and annual savings when using EXAIR products.  As an example, I used a 1” Flat Super Air Nozzle, model 1126, and compared it to a 1/8” open pipe.  (The reason behind the comparison is that the model 1126 can screw onto the end of the 1/8” NPT pipe.)  With an operation of 24 hours/day for 250 days a year, the amount of air used by an 1/8” open pipe is near 70 SCFM (1,981 SLPM) at 80 PSIG (5.5 Bar).  The model 1126 has an air consumption of 10.5 SCFM (297 SLPM) at 80 PSIG (5.5 Bar).  By putting the information in the Cost Savings Calculator, it determined that the ROI was in 2.1 days.  The annual savings was $5,355 USD per year.  Imagine if you replaced ten blow-off spots in your facility, the amount of money that could be saved.  Here is the worksheet below:

flat 1

The people that started to notice the savings were the utility companies that make electricity.  Depending on your location, electrical suppliers initiated a rebate program to use engineered nozzles in your facility.  Similar to other energy saving rebates, like LED light bulbs and high efficiency furnaces, the electrical providers notice a big savings when using EXAIR products.  If you qualify, the total cost to purchase and implement the EXAIR Super Air Nozzles are reduced.(Even if a rebate program has not been implemented in your area, the idea of saving energy and compressed air makes it very profitable and environmentally sound in changing over to EXAIR products).

To see if your utility offers rebates on compressed air optimizations, go to the DSIRE database. This database is easy to search and informative.

For Example, here in Ohio Duke Energy has a Prescriptive Incentive Program for its customers. The Prescriptive Incentive Program makes it easy for Duke Energy customers to receive an incentive for their natural gas and electric energy efficiency projects. Prescriptive Incentives are energy efficient measures paid per-unit, reimbursing the customer up to the total cost (including materials and labor) after the measures have been installed. See the image below for their incentives for using Engineered Nozzles;

Ohio Duke Energy Prescriptive Incentive Program

To discuss your application and how an EXAIR Intelligent Compressed Air Product can help your process and save you money, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer

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