Laminar Flow and Digital Flowmeters: An Explanation On How To Achieve Laminar Flow

When I see turbulent flow vs. laminar flow I vaguely remember my fluid dynamics class at the University of Cincinnati.  A lot of times when one thinks about the flow of a liquid or compressed gas within a pipe they want to believe that it is always going to be laminar flow. This, however, is not true and there is quite a bit of science that goes into this.  Rather than me start with Reynolds number and go through flow within pipes I have found this amazing video from a Mechanical Engineering Professor in California. Luckily for us, they bookmarked some of the major sections. Watch from around the 12:00 mark until around the 20:00 mark. This is the good stuff.

The difference between entrance flow, turbulent flow and laminar flow is shown ideally at around the 20:00 mark.  This length of piping that is required in order to achieve laminar flow is one of the main reasons our Digital Flowmeters are required to be installed within a rigid straight section of pipe that has no fittings or bends for 30 diameters in length of the pipe upstream with 5 diameters of pipe in length downstream.

This is so the meter is able to measure the flow of compressed air at the most accurate location due to the fully developed laminar flow. As long as the pipe is straight and does not change diameter, temperature, or have fittings within it then the mass, velocity, Q value all stay the same.  The only variable that will change is the pressure over the length of the pipe when it is given a considerable length.

Another great visualization of laminar vs. turbulent flow, check out this great video.

 

If you would like to discuss the laminar and turbulent flow please contact an Application Engineer.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 -Fluid Mechanics: Viscous Flow in Pipes, Laminar Pipe Flow Characteristics (16 of 34) – CPPMechEngTutorials – https://www.youtube.com/watch?v=rQcZIcEa960

2 – Why Laminar Flow is AWESOME – Smarter Every Day 208 – SmarterEveryDay – https://www.youtube.com/watch?v=y7Hyc3MRKno

 

 

When To Use The High Lift Reversible Drum Vac vs. The Reversible Drum Vac

One of my favorite TV shows growing up was Home Improvement with Tim Allen. One of the most memorable parts of the show was when Tim’s character would always state that when doing a job you need … MORE POWER!!!

In real life and within a production environment this is not always true. More often than not more power equals waste and inefficient use of the resources at hand. I know, I sound a lot like Tim Allen’s counterpart in the show, Al Borland. Well, the truth is, Al was usually right.  Here at EXAIR, we offer two different types of Reversible Drum Vac, the standard unit and the High Lift RDV.

The Reversible Drum Vac System converts a drum and dolly into a mobile pumping system.

The standard RDV will pull up to 96″ of water column when in suction mode. This is ideal for water-soluble coolants or other water-based rinses. The unit is paired with a 10′ vacuum/discharge hose to ensure optimal performance. The RDV will fill a 55-gallon drum with water in 90 seconds or less when operated at 80 psig inlet pressure. It will then empty the same drum even faster by discharging liquid at up to 166″ of water column displacement. To do both of these operations, fill or empty the drum the RDV will utilize 19 SCFM of compressed air. This is easily supplied within most industrial applications where that amount of compressed air usage can be overlooked.

EXAIR’s High Lift RDV makes cleaning out pits up to 15′ deep easy and fast.

If Binford manufactured a compressed air liquid vacuum, it would be the High Lift Reversible Drum Vac. This is the, “More Power” version of the RDV and can pull up to 180″ of water column when in vacuum mode. This can pull water-soluble coolants up to 15 feet below grade for those large machining centers that sit over the top of a coolant pit or those large footprint machines where a 20′ hose is needed to reach into and around the parts of the machine to where the coolant or liquid is housed. Another application would be for oil-based coolants or other petroleum-based oils/higher viscosity fluids. This will still discharge liquids at 166″ of water column when in positive displacement. The unit will outperform its predecessor and that comes with higher utilization of compressed air. While operating at 80 psig inlet pressure the unit will consume 43 SCFM of compressed air. This volume of air is still easily located within most industrial environments and is still less than the amount demanded by competitive units that do not offer the reversible feature of the High Lift Reversible Drum Vacs.

When it boils down to it, the High Lift Reversible Drum Vac will perform every task of the standard Reversible Drum Vac and will perform the vacuum portion of those tasks all faster due to the higher level of vacuum. When this higher level of vacuum isn’t needed, when the sump is at ground level and the coolant or liquid is around the viscosity of 50 weight motor oil or thinner then the standard RDV will work ideal for the application and would be the most efficient method to get the job done. When the liquid is higher viscosity or below ground level trying to pull it up out of a pit then the High Lift Reversible Drum Vac is the ideal tool to get the job done. Again, Al Borland had it right, more power is not always needed, sometimes it is better to keep it efficient.

If you would like to discuss your liquid vacuum application or any point of use compressed air application, please contact us. (Heck, I’ll even talk about Home Improvement if you are a fan too.)

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Best of Home Improvement so 1 eo01 More Power – @shary h – https://www.youtube.com/watch?v=ts9UONUMlCg

Max Refrigeration vs. Max Cold Temp Vortex Tubes

Here at EXAIR, our vortex tubes are offered in two separate series. The reason for this is to optimize the performance of the cold air temperature drop when operating with opposite ends of the cold fraction chart. The maximum refrigeration vortex tubes, 32xx series, perform optimally when they are set to a greater than 50% cold fraction.  The maximum cold temp vortex tubes, 34xx series, perform optimally when they are set to a less than or equal to 50% cold fraction. The cold fraction is discussed more in-depth within this link from Russ Bowman, Vortex Tube Cold Fractions Explained. This blog is going to explain a little further why one series of vortex tubes would be chosen for an application over another.

Cold Fraction
EXAIR Vortex Tube Performance Chart

Maximum refrigeration (32xx) vortex tubes are the most commonly discussed of the two types when discussing the optimal selection of the vortex tube for an application. The 32xx series vortex tubes achieve a maximum refrigeration output when operated at 100 psig inlet pressure with around  80% cold fraction. This would give a temperature drop from incoming compressed air temperature of 54°F (30°C). The volumetric flow rate of cold air will be 80% of the input flow which means only 20% is being exhausted as warm exhaust air. By keeping the flow rate higher the air is able to cool a higher heat load and is the reason the vortex tube is given a BTU/hr cooling capacity.

Vortex Tube Hot Valve Adjustment

Maximum cold temperature (34xx) tubes are less common as their applications are a little more niche and require a very pinpoint application. Rather than changing the temperature inside of a cooling tunnel or cooling an ultrasonic welding horn, the max cold temp vortex tube is going to have a minimum cold flow rate, less than 50% of input volumetric flow.  This minimal flow will be at temperature drops up to 129°F (71.1°C) from the incoming compressed air temperature.  This air is very cold and at a low flow. A 20% cold fraction exhausts 80% of the input volume as hot air. This type of volume would be ideal for sensor cooling, pinpoint cooling of a slow-moving operation, or thermal testing of small parts.

In the end, EXAIR vortex tubes perform their task of providing cold or hot air without using any refrigerants or moving parts. To learn more about how they work, check out this blog from Russ Bowman. If you want to see how to change the cold fraction, check out the video below. If you would like to discuss anything compressed air related, contact an application engineer, we are always here to help.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

About Dual Acting Reciprocating Compressors

When it comes to generating compressed air there are many types of compressors to utilize within a facility.  One of those types is a dual acting reciprocating compressor.  This is a type of positive displacement compressor that takes advantage of a piston style action and actually compresses air on both directions of the stroke.  Below you can see a video from a company that showcases how a dual acting compressor works and gives a good representation of how it is compressing the air on both directions of travel.

Dual_Recip
Click on this image for video

The reciprocating type of air compressor uses a motor that turns a crank which pushes a piston inside a cylinder; like the engine in your car.  In a basic cycle, an intake valve opens to allow the ambient air into the cylinder, the gas gets trapped, and once it is compressed by the piston, the exhaust valve opens to discharge the compressed volume into a tank.  This method of compression happens for both the single and double acting reciprocating compressors.

With a single acting compressor, the air is compressed only on the up-stroke of the piston inside the cylinder.  The double acting compressor compresses the air on both the up-stroke and the down-stroke of the piston, doubling the capacity of a given cylinder size.  This “double” compression cycle is what makes this type of air compressor very efficient.  A single acting compressor will have an operating efficiency between 100 cfm / 23 kW of air while the double acting compressor has an operating efficiency between 100 cfm 15.5 kW .  Therefore, electricity cost is less with a double-acting reciprocating air compressor to make the same amount of compressed air.

These compressors are ruggedly designed to be driven 100% of the time and to essentially be a Clydesdale of compressors.  They are commonly used with applications or systems requiring higher pressures and come in lubricated or non-lubricated models.

If you would like to discuss air compressors or how to efficiently utilize the air that your system is producing so that you aren’t giving your compressor an artificial load that isn’t needed, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

How Lowering Sound Levels Produces ROI

Sound levels and ROI don’t immediately link together in a quick thought. Unless you are me and things seem to link up that don’t always go together, like peanut butter and a cheese burger. (Trust me, just try it, or if you are near West Lafayette, Indiana just go try the Purvis Burger across the street from Purdue University.) The truth behind tying sound levels being reduced and ROI together is actually pretty simple.

For this example, I am going to stay fairly high level as we could get into some pretty deep measurements of what exactly could be a cost savings.  If we reduce the sound level being generated by point of use compressed air products that is easiest to do by implementing engineered blow off products as well as reducing the operating pressure. Let’s use this example: A 1/4″ copper tube that is being used as a blow off will give off a noise level of over 100 dBA from 3′ away.  The table below shows that at an 80 psig inlet pressure the same tube will also consume 33 SCFM of compressed air.

By installing a model 1100 1/4″ FNPT Super Air Nozzle on the end of this copper tube, we  reduce the noise level generated by the blow off to 74 dBA. This measurement is at the same 80 psig inlet pressure and from 3′ away, which is well below the OSHA standard for allowable noise level exposure.  This also gives a broader more defined pattern to the air stream which may permit a reduction in compressed air pressure.

The other factor this changes is that the air consumption is reduced by 19 SCFM of compressed air which then results in energy savings.  This ultimately ends in a simple ROI equation where we are simply using the compressed air reduction as the only variable for the return.

 

By reducing the air consumption of a process that operates 24/7, 250 days a year that equates to  a savings of 6,840,000 SCFM per year and that equates to $1,710.00 USD. This does not account for any reduction in paying for hearing protection that may no longer be needed, or increase in production because the application functions better.

So you see, reducing noise levels in a facility can easily amount to a sizable cost savings in energy going towards compressed air consumption.  If you would like to walk through any potential applications, please contact us. 

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Promos, Freebies, and Some Amazing Products

Like many companies, here at EXAIR we generally always have a promotional offering.  These rotate throughout the months and this month is no different.  The current offering involves the EXAIR Cold Gun Aircoolant Systems.

These systems help to reduce cutting fluid use, increase production speeds, increase tool life, and has helped more customers than I know.  One customer in particular is a maintenance worker from a welded tube manufacturer.  This facility had very little amount of downtime permitted due to the high efficiency and high volume of orders.  When a machine went down the maintenance team were in like a trauma team to determine the cause of failure and get it remedied to get the line back up and running. One of the biggest problems they would have is when they would have to dry machine a quick part to get the machine back up and running, this would either ruin tools or they would have to slow down the machining time to get the surface finish and dimensions they truly needed.  After talking with us the team ordered a Single Point Cold Gun Aircoolant System as these parts were generally smaller shafts or machine dogs.

They received the system in and sure enough a machine went down.  The crew went to work and once the part needed was found they got to work on their lathe trying to make a new piece.  The Cold Gun held itself straight to the headstock thanks to the integrated magnet and the flexible single point hose kit routed the cold air straight to the cutting point.  They didn’t have to fill up the liquid tank or setup the mist system on the lathe, they simply turned on the compressed air and let the lathe do the work.  They were able to take what had recently been around a three hour machine job with heavy wear on tooling to a two hour job, no finish pass was needed on the part, and their tools weren’t completely spent by the end of the job.

They got the part back into the machine, made adjustments, and then went to work getting the machine back into production.

Right now, if you would like to try out a Cold Gun Aircoolant System you can order before 12/31/2019 and use the link to order through our promotion in order to receive a free Dual Point Hose Kit with your qualified purchase.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

A Brief History of Compressed Air

So where exactly did compressed air come from? How did it become so widely used and where will it go? Both of these are great questions and the answers lie below.

Compressed air can be traced all the way back to the classic bellows that were used to fuel blacksmith fires and forges.  These started as hand pumped bellows, they then scaled up to foot pumped, multiple person pumped, oxen or horse driven and then eventually waterwheel driven.  All of these methods came about due to the demand for more and more compressed air. These bellows did not generate near the amount of air pressure or volume needed for modern day practices yet they worked in the times.  These early bellows pumps would even supply miners with air.

With the evolution of metallurgy and industry these bellows were replaced by wheel driven fans, then steam came about and began generating more industrial sources of power.  The main issue with steam was that it would lose its power over longer runs of pipe due to condensing in the pipes.  Thus the birth of the air compressor was born. One of the largest projects that is noted to first use compressed air was in 1861 during the build of the Mont Cenis Tunnel in Switzerland in which they used compressed air machinery.  From here the constant need and evolution for on-demand compressed air expanded.  The picture below showcases two air compressors from 1896.

compressed_air_28189629_281459402261829
Air Compressors from the old days.

The compressors evolved over time from single stage, to two-stage reciprocating, on to compound, rotary-screw compressors, rotary vane, scroll, turbo, and centrifugal compressors with variable frequency drives.  The efficiency of each evolution has continued to increase.  More output for the same amount of input.  Now we see a two-stage compressor, considered old technology, and wonder how the company can get any work done.

All of the technological advances in compressor technology were driven by the demand sides of the compressed air systems.  Companies needed to power more, go further, get more from less, ultimately increase production.  With this constant increase in demand, the supply of compressed air increased and more efficient products for using compressed air began to evolve so the air was used more efficiently.

Enter EXAIR, we evolved the blowoff to meet the increasing demands of industrial companies to get the same amount of work done with less compressed air. We have continually evolved our product offering since 1983.  It all started with just a few typed pages of part numbers and has evolved to a 208 page catalog offering of Intelligent Compressed Air Products® for industry.  We will also continue to evolve our product designs for continued improvement of compressed air usage.  This is all to better help companies retain their resources.

cat32_500p
EXAIR Catalog 32

If your company uses compressed air and you aren’t sure if it is efficiently being utilized, contact an Application Engineer.  Thanks for joining us for the brief history lesson, we look forward to hearing from you and seeing what the future brings.

Brian Farno
Application Engineer
@EXAIR_BF BrianFarno@EXAIR.com

 

Compressed air (1896) (14594022618).jpg – Wikimedia Commons – Internet Archive Book Images – Link