How to Calculate and Avoid Compressed Air Pressure Drop in Systems

EXAIR has been manufacturing Intelligent Compressed Air Products since 1983.  They are engineered with the highest of quality, efficiency, safety, and effectiveness in mind.  Since compressed air is the source for operation, the limitations can be defined by its supply.  With EXAIR products and pneumatic equipment, you will need a way to transfer the compressed air from the air compressor.  There are three main ways; pipes, hoses and tubes.  In this blog, I will compare the difference between compressed air hoses and compressed air tubes.

The basic difference between a compressed air hose and a compressed air tube is the way the diameter is defined.    A hose is measured by the inner diameter while a tube is measured by the outer diameter.  As an example, a 3/8” compressed air hose has an inner diameter of 3/8”.  While a 3/8” compressed air tube has an outer diameter that measures 3/8”.  Thus, for the same dimensional reference, the inner diameter for the tube will be smaller than the hose.

Why do I bring this up?  Pressure drop…  Pressure Drop is a waste of energy, and it reduces the ability of your compressed air system to do work.  To reduce waste, we need to reduce pressure drop.  If we look at the equation for pressure drop, DP, we can find the factors that play an important role.  Equation 1 shows a reference equation for pressure drop.

Equation 1:

DP = Sx * f * Q1.85 * L / (ID5 * P)

DP – Pressure Drop

Sx – Scalar value

f – friction factor

Q – Flow at standard conditions

L – Length of pipe

ID – Inside Diameter

P – Absolute Pressure

 

From Equation 1, differential pressure is controlled by the friction of the wall surface, the flow of compressed air, the length of the pipe, the diameter of the pipe, and the inlet pressure.  As you can see, the pressure drop, DP, is inversely affected by the inner diameter to the fifth power.  So, if the inner diameter of the pipe is twice as small, the pressure drop will increase by 25, or 32 times.

Let’s revisit the 3/8” hose and 3/8” tube.  The 3/8” hose has an inner diameter of 0.375”, and the 3/8” tube has an inner diameter of 0.25”.  In keeping the same variables except for the diameter, we can make a pressure drop comparison.  In Equation 2, I will use DPt and DPh for the pressure drop within the tube and hose respectively.

Equation 2:

DPt / DPh = (Dh)5 / (Dt)5

DPt – Pressure drop of tube

DPh – Pressure Drop of hose

Dh – Inner Diameter of hose

Dt – Inner Diameter of tube

Thus, DPt / DPh = (0.375”)5 / (0.25”)5 = 7.6

As you can see, by using a 3/8” tube in the process instead of the 3/8” hose, the pressure drop will be 7.6 times higher.

Diameters: 3/8″ Pipe vs. 3/8″ tube

At EXAIR, we want to make sure that our customers are able to get the most from our products.  To do this, we need to properly size the compressed air lines.  Within our installation sheets for our Super Air Knives, we recommend the infeed pipe sizes for each air knife at different lengths.

There is also an excerpt about replacing schedule 40 pipe with a compressed air hose.  We state; “If compressed air hose is used, always go one size larger than the recommended pipe size due to the smaller I.D. of hose”.  Here is the reason.  The 1/4” NPT Schedule 40 pipe has an inner diameter of 0.364” (9.2mm).  Since the 3/8” compressed air hose has an inner diameter of 0.375” (9.5mm), the diameter will not create any additional pressure drop.  Some industrial facilities like to use compressed air tubing instead of hoses.  This is fine as long as the inner diameters match appropriately with the recommended pipe in the installation sheets.  Then you can reduce any waste from pressure drop and get the most from the EXAIR products.

With the diameter being such a significant role in creating pressure drop, it is very important to understand the type of connections to your pneumatic devices; i.e. hoses, pipes, or tubes.  In most cases, this is the reason for pneumatic products to underperform, as well as wasting energy within your compressed air system.  If you would like to discuss further the ways to save energy and reduce pressure drop, an Application Engineer at EXAIR will be happy to assist you.

 

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Static Elimination for Hose, Pipe, Extrusion, Cable and Wire

EXAIR’s  Gen4 Super Ion Air Wipe provides a uniform 360 degree ionized air stream that clamps around a continuously moving part to eliminate static electricity and contaminants. It is ideal for removing dust, particulates and personnel shocks on pipe, cable, extruded shapes, hose, wire and more. This engineered product has undergone independent laboratory tests to certify it meets the rigorous safety, health and environmental standards of the USA, European Union and Canada that are required to attain the CE and UL marks. It is also RoHS compliant. New design features include a metal armored high voltage cable to protect against abrasion and cuts, a replaceable emitter point, integrated ground connection and electromagnetic shielding.

g4siaw_3mb

The Gen4 Super Ion Air Wipe uses a small amount of compressed air to entrain high volumes of ambient air. Two shockless ionizing points powered by our Gen4 UL Component Recognized 5kV Power Supply fills the air stream with static eliminating ions. That airflow impacts the surface of the material running through the air wipe and neutralizes the charge.

The Gen4 Super Ion Air Wipe, which compliments EXAIR’s complete line of Gen4 Static Eliminators, has an aluminum construction that is lightweight and easy to mount using the tapped holes provided. Two sizes include a 2 inch (51mm) diameter and a 4 inch (102mm). There are no moving parts to wear out. Visit EXAIR.com to see the entire Gen4 Static Eliminator product line and 1/2 inch through 11 inch Super Air Wipes for applications without static.

Purchase a Gen4 Super Ion Air Wipe through our online promotional before March 31st, 2019 and receive a fee AC Sensor.

absesqmaster_300sq

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

Jordan Shouse
Application Engineer
Send me an email
Find us on the Web 
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Twitter: @EXAIR_JS

The Case For The EXAIR Super Air Wipe

If you’ve ever used an air gun to blow something off, you’re familiar with the cleaning ability of compressed air.  If you can get the whole object blown off from where you’re standing, there really is no substitute…but what if you need to get to the other side…or sides?

Even if your product is not on fire, you probably wouldn’t want to “limbo” under it with an air gun…

This is where the EXAIR Super Air Wipe comes in…they allow you to blow a continuous, uniform 360° air stream, all around your product.  Consider their benefits:

*Sizes: the Super Air Wipe’s compact ring design means it won’t take up a lot of room; you just need a few inches, in any direction, to install one.  We stock them in eleven sizes, from 11″, all the way down to our brand-new 3/8″ diameter.

*Durability:  All EXAIR Super Air Wipes are assembled with stainless steel shims and hardware.  Models up to 4″ come with a rugged, stainless steel wire braided hose, connecting the two halves for compressed air supply.

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

*Ease of installation:  Smaller sizes can be supported by the compressed air supply line, if a pipe is used and threaded into the connector hose’s 1/4 NPT port.  Larger sizes can likewise be adequately supported with pipe to both halves. All models have a bolt circle of 1/4″-20 tapped holes for more permanent and rigid mounting.  The split ring design is another key feature:

Simply open the two halves, and clamp them around your product…no threading!

*Corrosion resistance: Depending on the environment in which the Super Air Wipe will be installed, we offer them with aluminum (3/8″ – 11″ sizes) or stainless steel (3/8″ – 4″ sizes) bodies.

*Temperature rating: Aluminum Super Air Wipes are good to 400°F (204°C) and stainless steel models are good to 800°F (427°C.)

*Range of operation: We install a 0.002″ thick shim in all stock Super Air Wipes; this is suitable for a wide range of typical industrial/commercial blow off applications…a Pressure Regulator can then be used to “dial in” the air flow precisely to meet specific needs.  If a job calls for higher force & flow, additional 0.002″ shims can be installed.  Shim Sets come with the Super Air Wipe Kits, or individual shims can be ordered separately.

*Performance: Before the Super Air Wipe, a ring of nozzles was commonly used.  In fact, they still are, but we’re trying to fix that, at every opportunity we come across.  Problem with those is, it’s hard to get an even air flow all around, which leads to inconsistent blow off.  They can also be loud & inefficient, as we’ve found in numerous Efficiency Lab tests and Case Studies, like this one…

These wasteful and loud modular plastic tube blow offs…
…were replaced with EXAIR Super Air Wipes. 24 such replacements netted the customer an annual compressed air cost savings of over $13,000.00.

…and this one…

Implementing a Super Air Wipe salvaged a $30,000 job for this customer. Click on the picture to read all about it in our Case Study Library (registration required.)

Do you have a challenging blow off application that you need help with?  Call us to find out how an EXAIR Super Air Wipe (or another one of our Intelligent Compressed Air Products) can be a simple, quick & easy solution.

Custom Solutions For Conveying Dry Material

The ideal solution for conveying large volumes of material over long distances.

EXAIR’s Line Vac compressed air operated conveyors have no moving parts or motors to wear out, providing a maintenance free way to move dry material from one location to another. We offer several different types and sizes of Line Vacs like our Standard Line Vacs, available from 3/8″ up to 5″  or our Threaded Line Vacs, with NPT threaded connections up to 3″. The Heavy Duty Line Vac are constructed of Hardened Alloy for superior abrasion resistance, available in sizes from 3/4” to 3”, smooth and threaded connections or the Light Duty Line Vac commonly used for smaller volume, shorter distance processes, with sizes from 3/4″ to 6”. We even offer Sanitary Flange Line Vacs from 1-1/2″ up to 3″ for processes requiring frequent cleaning. All of these products are in stock, ready to ship from our factory here in Cincinnati, Ohio.

For over 34 years, EXAIR has been manufacturing Intelligent Compressed Air Products and we understand that there may be “special” cases where a stock product isn’t going to fit a specific need or requirement. What sets us apart from our competition is that we are able, with a little help from the customer, to engineer and manufacture custom made products, like the Line Vac Conveyors, to fit the specific demand of a unique application.

A few examples are shown below:

Flanged design, easy to install


This special 3/4″ Stainless Steel flanged Line Vac is being used to remove acidic vapors after a silicon wafer etching process. The flanged design allowed the user to direct mount to the machine, eliminating the need for other expensive modifications.

 

 

 

Chemical resistant construction for washdown areas

 

 

A customer was needing a special Line Vac for a chloride wash area due to the aggressive chemicals. We were able to make a custom 1-1/2″ Line Vac in PVDF construction for corrosion resistance and QF flanges for easy maintenance and cleaning.

 

 

 

Custom funnel design for small, granulated material like sugar or salt

 

This special funnel shaped Line Vac is being used in a a small packet filling operation. The unique design assured for a clog free process by keeping the granulated material moving through the tube.

 

 

 

 

 

Miniature size for confined workspaces

 

A company was needing a miniature version of a Line Vac to remove microscopic debris in an integrated circuit chip making process. The barb fittings allowed for easy installation into the small work place.

 

 

 

 

 

These are just a few examples of how we are able to meet the demands of a wide variety of extraordinary processes. Whether you are looking to move “common” materials like plastic pellets or maybe something “off the wall”, chances are we have the resources to provide an engineered solution to fit your need. Our application engineers are standing by, so give us a call and let us put our expertise to work for you!

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

When Is A Half Inch Not A Half Inch? When It’s Half Inch Pipe, Of Course!

People have been using pipe to transport fluids for thousands of years. Archeologists have discovered evidence that the Chinese were using pipes made of reeds for irrigation as early as 2,000 B.C. Lead pipe began to supplement, and eventually replace, the Roman aqueducts in the first century A.D. In the early 1800’s, someone got the idea to use gas burning lamps to light city streets, and, over the next few years, men like James Russell and Cornelius Whitehouse came up with better and better methods of mass producing metal tubing and pipes.

Over the course of the 19th Century and the Industrial Revolution, iron pipe came to be manufactured in standard sizes, which were called out by the inside diameter of the pipe. ¼” pipe had a ¼” ID, ½” pipe had a ½” ID, ¾” pipe had a ¾” ID, etc. Iron pipe could be found in any facility that needed to move a gas or a liquid: factories, power generating stations, chemical plants…you name it.

As engineers and metallurgists came up with new ways to produce pipe, technological advances led to the ability to decrease the wall thickness and still maintain high structural integrity. This was a HUGE improvement: not only could piping manufacturers make more pipe with less material, bringing down the cost, it was also lighter in weight, making it easier to transport, handle, and install. Because of the massive amount of existing piping already in place, it made sense to keep the outside diameter the same, so that all the fittings would match when these facilities went to replace worn out or damaged pipe. So, the inside diameter was increased. That’s why, today, ¼” pipe has a 0.36” ID, ½” pipe has a 0.62” ID, ¾” pipe has a 0.82” ID, etc. Lower cost, lighter weight, more flow capacity…it’s all good, right?

Well, yes, but sometimes, it can lead to confusion, especially when we’re talking about properly sized compressed air lines. See, we know how much compressed air will flow through certain sized pipes of specific lengths. The Installation & Operation Instructions for all of our products contain recommended infeed pipe sizes to ensure sufficient air flow. Keep in mind, these are Schedule 40 pipe sizes, and should not be confused with hose or tubing sizes, which usually report the outside diameter but could also report the inside diameter, depending on the source.

Consider this example: you want to install an 6” Super Air Knife in a location 10 feet from the compressed air header. Following the “Infeed Pipe Size Length of Run” column (10’) down, we see that this will require a ¼” SCH40 pipe, which has an ID of 0.36”. If you want to use hose or tubing to supply it, that’s fine – it’ll have to have a 3/8” ID, though, or you’re going to risk “starving” the Air Knife for air. If you choose a 3/8″ tube remember that dimension is usually referring to the outside diameter of the tube and automatically means your inside diameter is smaller than we would recommend.

SuperAirKnifeInfeedPipe

If you’d like to learn more, it’s actually been a pretty popular blog topic as well:

The Importance of Proper Compressed Air Supply Lines

Video Blog: Proper Supply Plumbing For Compressed Air Products

Top 6 Compressed Air Plumbing Mistakes and How to Avoid Them

…and that’s just to name a few.  If you have specific questions about how to properly supply your EXAIR product(s), you can give us a call – we’re eager to help!

Russ Bowman
Application Engineer
EXAIR Corporation
(513)671-3322 local
(800)923-9247 toll free
(513)671-3363 fax
Web: www.exair.com
Twitter: twitter.com/exair_rb
Facebook: http://www.facebook.com/exair