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

Super Air Wipe at Sea

I recently worked with a Chief Engineer on a large shipping boat who was having issues with water being brought in by the mooring cables. That salt water was getting into the maintenance room where the mooring cables were wound around a large spool. He wanted to remove the water from the cable before it went below deck so the extra water could just run off the deck back into the ocean.

After talking a bit we decided on a 4″ Super Air Wipe constructed of 303 stainless steel. This way the extra water would be removed and any debris the cable pulled in with it.

Mooring Cable going thru a EXAIR Super AirWipe

The Super Air Wipes provide a full 360° conical airflow that is used to blow-off, cool, clean and dry products. A Coanda profile is designed into the body of the unit to maximize entrainment of ambient air as well as give the precision angle for the air to exit from. This gives the air stream impacting the target zone a 30° angle to the surface in order to provide a substantial shear force for debris removal. This also ensures the large volume of ambient air entrained will all travel the correct direction and not become turbulent before impinging on the surface.

To meet all the tasks at hand, the Super Air Wipes are offered in two main materials of construction. Aluminum body with brass air fittings, connected with stainless steel hardware, shim and connecting hose for up to 4” (102mm). As well as 303 stainless steel body with stainless steel bolts, shim, the connecting hose for up to 4” (102mm) and fittings. The stainless-steel components give the units better corrosion resistance, higher temperature ratings, and more durability in harsh industrial environments.

The aluminum Super Air Wipe is available in 11 sizes; the stainless steel Super Air Wipe comes in 5 sizes…all from stock.

EXAIR stocks the aluminum Super Air Wipes with inner diameters from 3/8” (10 mm) for wire and cables up to 11” (279mm) for large pipes and hoses. The aluminum models have a temperature rating up to 400oF (204oC). We also stock the stainless-steel models from ½” (13mm) to 4” (102mm) inner diameters, and they have a temperature range up to 800oF (427oC). If you require different diameters or materials, we can do that as well easily.

With the creation of the Super Air Wipe, uniform cleaning, cooling, and blowing around the outside of parts is a simple task. You don’t have to worry about a variety of nozzles to target the circumference or a fabricated blow-off device that will waste air and take much time out of your day. A simple purchase of the Super Air Wipe Kit will solve the problem and keep production going. If you need help in selecting the proper size or want to know what material we would recommend for your application, contact us.

Jordan Shouse
Application Engineer

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A Closer Look At The EXAIR Reversible Drum Vac Systems

Amidst the multitude of products that EXAIR offers, we have a full line of Industrial Housekeeping Products, our pneumatic vacuums.  Within this product line is the Reversible Drum Vac System. This system is a product that I personally encountered fresh out of college in my first job within the metal cutting industry. I would actually carry a standpipe, 10′ hose, chip wand, and reversible drum vac in a job box to every machine tool show as well as some larger machine repair jobs I was responsible for.

EXAIR’s model 6196 – Reversible Drum Vac System

At the time, I didn’t know it was an EXAIR product as it had been around for years before me and had seen better days, had been used thoroughly and all I knew was that I could empty a sump faster than anyone else that I saw anywhere in the shows or even the large sump evacuation systems some of these shops had that almost had to be towed around with a forklift.  This was a marvel to me as I had honestly been showed one time how to use it from another team member and I was able to grasp all the knowledge needed to operate (Not because I am a genius or anything, it’s just that simple). The few things I was not aware of is what the other options for the Reversible Drum Vac Systems were. All I knew is what I had when I worked at that company and didn’t know what kind of possibilities there were to expand our capabilities, so hopefully, this will help you see all the options.

While EXAIR currently offers four different types of liquid vacuums, they are all based on the Reversible Drum Vac or the High Lift Reversible Drum Vac. The Reversible Drum Vac itself is available in four capacities of drums and several options for each. The three capacities available are 5, 30, 55 or 110 gallon.

The 5 gallon is perfect for bench-top machines or small tests that are taking less than five gallons of liquid.  The system can still pull up to 96″ of H2O and discharges at an even faster rate than it vacuums which is 30 GPM.  The system includes the container, lid, 10′ vacuum/discharge hose, aluminum chip wand, Reversible Drum Vac, standpipe, quick connect,  spill recovery kit, and several other ancillary attachments to make any liquid reclamation job easy and quick. The Deluxe Mini Reversible Drum Vac system adds on a drum dolly which makes this an easy to transport compact and efficient liquid spill/recovery system.

 

 

The 30, 55, and 110-gallon capacity systems are available in a basic, deluxe, and premium system. The Basic includes the standpipe for a given size, 10′ vacuum/discharge hose, quick connect, aluminum chip wand, and Reversible Drum Vac.  The Deluxe System adds a spill recovery kit, drum dolly, magnetic tool holder, and other ancillary plastic tools. The premium adds the appropriate drum with a tight sealing lid, latch/bolt ring, 20′ compressed air hose w/ quick disconnects,  as well as upgrades plastic tools to cast aluminum tools.

If you would like to discuss which of these systems is going to fit your needs and give you the ability to fill a drum ta 30 GPM and empty it even faster, please contact me.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Torque Values and Tapered Threads – Do They Go Together?

IMG_20200202_155004_377.jpg

Over the past few weeks, I have been working on various cars in the garage with some good friends. We generally get together and help each other out to make the jobs go easier as well as help each other learn more about keeping our family’s vehicles safe and even helping out some others that don’t have the means to work on their own vehicles. Throughout these repairs, we always end up in some type of discussion over something fairly technical. Sometimes it is the proper installation of a part such as take the bolts to snug, back them out, then torque to half the total torque value, back off again, then finally tighten to the complete torque.

We also share different ways of doing the jobs, such as how to lessen the amount of hot oil you are about to pour all over your hand, or how to get that rusted bolt out without a torch and without breaking it. One discussion that comes up quite frequently is torque specs and then the torque spec for a tapered thread.

In case you were not aware, the NPT or BSPT (male) inlets on EXAIR products are both a tapered thread. Tapered threads are generally used on pipe fittings under pressure to seal better and provide a secure engagement. When comparing this to a standard bolt, or straight thread, one is generally accustomed to receiving a torque spec on just how tight to get the fitting or threaded product. For example, the 1/4-20 bolts used in our Super Air Knives are torqued to 7.5 ft-lbs. in order to properly seal the cap, shim, and body together. These are straight threads and thus a torque spec is often driven by the material, size, and thread of the bolt. Torque on tapered threads such as NPT or BSPT fittings is not as easy to find, and not really reliable.

For tapered threads, the engagement of the thread is not always at the same point due to differing tolerances on thread dimensions. These differences create different points of thread engagement with the corresponding thread it is tightening into. For these scenarios, the torque specification is not always best suited as a numeric value. If you search hard enough you can find a table like the one shown below, but again, not the best value to use when installing a tapered thread.

Size in-lbs N-m
1/16″ 5 0.57
1/8″ 7 0.79
1/4″ 16 1.81
3/8″ 23 2.6
1/2″ 30 3.39
3/4″ 54 6.1
1″ 78 8.81

I personally would not use a straight numeric torque when tightening something with stainless steel thread into a brass fitting, or other dissimilar materials together. For this scenario, I would recommend using something like the table below. The TPFT value is, turns past finger tight. This means you would snug the super air nozzle, vortex tube, or other fittings by hand to finger tight. Then using a wrench or two if needed, turn the fitting to the correct number of revolutions for the given thread size. By utilizing this method and the correct amount of thread sealant, see John Ball’s video blog below, you can ensure there will not be a concern on whether or not the joint will leak and also if the fitting is tight enough.

NPT Size TPFT
1/8″ 2-3
1/4″ 2-3
3/8″ 2-3
1/2″ 2-3
3/4″ 2-3
1″ 1.5-2.5

If you would like to discuss torque settings, installation of your engineered compressed air solution, or even what might be wrong with your minivan, contact us.

Brian Farno
Application Engineer/Garage Mechanic Extraordinaire
BrianFarno@EXAIR.com
@EXAIR_BF