What Is The Difference Between Pressure & Flow In A Compressed Air System?

There is rarely a day that goes by that I don’t receive a call from someone who has a need for a compressed air product and when I state the SCFM requirements of the device they respond back with the psi rating of their air compressor.  Many technicians simply do not understand the difference between the two.  Simply put psi (pounds square inch) is force and CFM (cubic feet per minute) is flow.

A simple illustration would be to contrast a 12 VDC powered air compressor that many people carry in their trunks to inflate car tires.  They will inflate your car tire to 35 psi in a matter of minutes.  While the air compressor at a tire shop can inflate a car tire in a minute or less.  What is the difference?

12 VDC Air Compressor
12 VDC Tire Inflator

 

Simply put, the flow. Both inflate the tire to the desired pressure but the one with largest flow (volume) does it much faster.  In the case of a compressed air product such as an air nozzle, the pressure required to operate is only one part of what is necessary to operate the device effectively, you need to have enough flow or CFM.

Let us now consider an EXAIR 1100 Super Air Nozzle, its rated performance of 13 ounces of force at 12″ distance from the nozzle is derived from supplying 14 SCFM @ 80 psi.  The typical home use air compressor that runs on 110 VAC (Generally 2 HP maximum) will not generate the flow (volume /CFM) at 80 psi to run the nozzle at peak force, just as it would not generate enough flow to fill the tire as quickly as the industrial compressor at a tire shop.

When an open tube, pipe or inefficient nozzle is placed at the end of an air line to provide blow off for cooling or cleaning it demands much greater volume from the compressor. If the compressor cannot keep up the force (pressure) of the system will decline. Replacing an open tube or pipe with an EXAIR engineered nozzle will require less compressed air volume which, in turn, will give the compressor more ability to provide full pressure and force upon your application.

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EXAIR 1100 Super Air Nozzle

If you would like to discuss air consumption of any of EXAIR’s engineered solutions, I would enjoy hearing from you…give me a call.

Steve Harrison
Application Engineer
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12 VDC Tire Inflator Image courtesy of Moto Service Dinamarca

 

A Brief History of the Air Compressor

Essentially compressed air technology was first used with the knowledge of how to start a fire.  Humans learned that to get the fire started, blowing helped the process, healthy human lungs can generate approximately .02 to .08 bar or .3 to 1.2 PSI.

At the beginning of the metallurgical age (approximately 3000 B.C.) a higher volume of air than what human lungs could produce was required to the reach the temperatures required to melt and form metals such as copper, tin, lead, etc.  This need lead to the hand-operated bellows, the first mechanical air compressor.  Approximately 1500 years later the more efficient foot powered bellows was developed.

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The foot powered bellows was followed by water powered bellows and was the mainstay for more than 2000 years.  However as blast furnaces came into being the need for compressed air increased.  This lead John Smeaton in 1762 to design a water wheel that powered a blowing cylinder and this began to replace bellows.  In 1776 John Wilkinson developed an efficient blasting machine and this was the beginning for mechanically powered air compressors.

As time progressed the idea of transmitting energy via compressed air became acceptable.  This idea was demonstrated around 1800 when the newly invented pneumatic rock drill was used to tunnel 80 miles under Mt. Cenis to connect Italy & France by rail.  This was an extraordinary feat for the time and garnered global interest.  This event perpetuated great interest into pneumatic powered devices  and brought us the air powered motors, clocks and even beer dispensers!

While compressed air is capable of transmitting energy long distances and performing tremendous work it also referred to as the 4th utility in industrial plants due to its cost.  We at EXAIR have been promoting compressed air conservation and safety using highly engineered products for 35 years!  Our products wring the maximum of energy out of every SCFM fed to them by using air entrainment and the Coanda effect.  Not only are we conserving your compressed air we offer products that are quiet and can’t be dead ended which prevents air embolisms.

If you are interested in discussing conserving compressed air and/or compressed air safety, I would enjoy hearing from you.

Steve Harrison
Application Engineer

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Protect Personnel from Noise with Engineered Products

Sound can be defined as vibrations that typically travel as an audible wave through mediums that can be a gas, liquid or solid. For this blog we will concern ourselves with sound travelling through a gas (atmosphere) in an industrial setting.

Sound is energy that travels in waves and is measured by its frequency (cycles per second) and amplitude (intensity). A common unit of measurement for sound energy is the decibel. The decibel (abbreviated with dBA) is a unit-less number that is based on the logarithm of a known measured quantity to a reference quantity. Without reciting the equation for every increase of 3 dBA is a doubling of sound energy or twice as loud.

Since our focus is on industrial sound one might question why be concerned at all, after all sound emanates from most machines and devices. The reason for concern is that there are OSHA regulations regarding the amount of time workers can be exposed to different levels of sound in their workday as illustrated below. These limits are in place to protect personnel from Noise Induced Hearing Loss or NIHL. When the damage to anyones hearing is caused by their profession, it is also referred to as Occupational Hearing Loss or OHL.

After monitoring for noise, NIOSH and the CDC next recommend administrative controls to minimize or eliminate the noise hazard (click for their helpful PDF). This would include the use of noise reducing EXAIR products like Super Air Nozzles, Air Knives and Air Amplifiers.

dBA Chart.JPG
OSHA Maximum Allowable Noise Exposure

When considering the many items in an industrial setting that produce loud sounds the list would be exhaustive. Many of them simply produce loud sounds that can’t be eliminated or reduced while on the other hand there are some that can. Some of the noisiest offenders that plants have control over are air powered tools and open tube blow-offs.  Eliminating inefficient methods of part blow off & part cleaning with an engineered solution allows a company to significantly reduce the level of sound in their plant, improve worker safety and save money on compressed air consumption.

Employers are required to provide hearing protection to employees whom are exposed to sounds above 90 dBA on a Time Weighted Average (TWA). Without digressing into the formulas TWA calculates a workers daily exposure to occupational sounds by taking into account the average levels (in dBA) and the time exposed to different levels.  This is the how OSHA assesses workers exposure and what steps should be taken to protect the workers.

To conclude, plants need to be mindful of the OSHA regulations for sound levels, time of exposure and that hearing protectors wear out. Earmuff seals can lose their elasticity and reduce their effectiveness and the soft pre-molded earplugs can wear out in a day and need replaced.  Keep a good supply on hand and OSHA suggests letting workers with noisy hobbies take them home for protection off the clock!

If you would like to discuss reducing noise or any EXAIR product, I would enjoy hearing from you…give me a call.

Steve Harrison
Application Engineer

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Atomizing Spray Nozzles from EXAIR

Do you ever need to spray a liquid?  If so lets look at two of EXAIR’s Atomizing Spray Nozzles or ASN for short.  The first model we will discuss is the AD1010SS Internal Mix Deflected Flat Fan Pattern.

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AD1010SS Internal Mix Deflected Flat Fan Pattern

To begin with all EXAIR ASN’s are made from SS for durability and liquid compatibility.  As its name implies it creates a flat fan pattern that exit’s the nozzle perpendicular to the air & liquid inlets as shown above.  This unique design lends itself nicely to applications with space constraints.  The AD1010SS is the ideal choice for coating the inside of enclosures or ductwork.  It is compatible with liquids up to 300 centipoise and the air and liquid are mixed in the air cap.  The AD1010SS is designed for pressure fed applications not requiring independent air and liquid control.  What is meant by that statement is that if you vary either the air or liquid pressures you change the spray pattern and volume.  See the chart below for clarification on pressures, volumes and spray patterns.

AD1010SS Pressures
AD1010SS Chart

Next we will look at EXAIR model AT1010SS internal mix 360° hollow circular pattern ASN.

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AT1010SS 360° Circular Spray Pattern Nozzle Can Be Used To Coat Inside Diameters Or Cover A Broad Area Of Over 4′

The AT1010SS internal mix 360° nozzle is designed for applications where the spray pattern must be oriented away from the nozzle in all directions.  360° nozzles are ideal where a smooth, even coating is needed on the ID of a pipe or similar ductwork.  It is compatible with liquids up to 300 centipoise and the air and liquid are mixed in the air cap.  The AT1010SS is designed for pressure fed applications not requiring independent air and liquid control.  As above if you vary either the air or liquid pressures you change the spray pattern and volume.  See the chart below for clarification on pressures, volumes and spray patterns. They also work great for operations where a mist over a broad area is needed, such as dust suppression, humidification and cooling.  See the chart below for clarification on pressures, volumes and spray patterns.

AT1010SS Chart
AT1010SS Chart

If you would like to discuss EXAIR’s Atomizing Spray Nozzles or any EXAIR compressed air product, I would enjoy hearing from you…give me a call.

Steve Harrison
Application Engineer

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Do You Need 30 Days for Testing?

Not long ago while checking out of a motel my laptop bag that was attached to the handle on my suitcase fell forward and the impact shattered the screen on the laptop.  Upon turning the computer on I realized that a new screen was in order.

I waited until I arrived at home and found what I thought to be the correct monitor and quickly ordered it.  It arrived two days later and I painstakingly took the laptop apart and exposed the mounting frame.  The removal of the broken screen and the installation of the new was not too difficult but the cable connector was less than robust and was very tight.  Carefully I worked it back and forth and it came free.

Installation and reassembly went quickly and then I powered up the machine.  I was only greeted with a series of very loud and annoying beeps.  At that point I shut it down and called the company I purchased the screen from and described the issue.  They determined that the resolution of the screen was incorrect for my laptop and that I needed a different model.  They said I could return the incorrect one and upon inspection receive a credit less the return shipping.  At that point I ordered the correct screen and packaged up the wrong one and dropped it off at the parcel delivery service.

The new model arrived and it installed easily and worked perfectly.  I waited patiently and never did see a refund so I called the company and they said that it was an oversight on their end and that it would be corrected within 48 hours.  Sure enough they issued the credit and money was credited back to my account with one exception, the 40% restocking fee!

I can tell you that EXAIR is not that way!  If you order the wrong item or are not satisfied for any reason and the item was purchased within the last 30 days we will facilitate the return and ZERO restocking fee. There are a multitude of reasons our customers would want to take advantage of our 30 day guarantee and we make it a simple transaction if you need to take advantage of it too. Testing is one reason a customer would use this 30 days, other customers may have ordered incorrectly or released product inadvertently, they may have wanted a small sample for a meeting or demonstration at a customers location.

30 day money back guarantee
EXAIR Guarantee

If you want to discuss any EXAIR product, I would enjoy hearing from you…give me a call.

Steve Harrison
Application Engineer
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Video Blog: EXAIR’s Universal Air Knife Mounting System

Using EXAIRS Universal Air Knife Mounting System greatly ease’s the installation of all Air Knives (Except PVDF).  It will save you the time and expense of designing and fabricating your own mounting system which will maximize your uptime and keep your staff focused on key plant tasks!

Please note the table below that highlights the recommended number of the Universal Air Knife Mounting System to use for the various length of Air Knives.

Length Of Air Knife Number of UAKMS
3″ – 18″ 1
24″ – 54″ 2
60″ 3
72″ – 95″ 4
96″ – 108″ 5

If you would like to discuss Universal Air Knife Mounting System, Air Knives or any EXAIR compressed air product, I would enjoy hearing from you…give me a call.

Steve Harrison
Application Engineer

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EXAIR Heavy Duty Safety Air Gun With Accessories Improves Effectiveness and Safety

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Model 1310-12 Heavy Duty Safety Air Gun, With 12″ Extension & 1100 Super Air Nozzle

In rugged industrial environments the EXAIR Heavy Duty Safety Air Gun delivers powerful blasts of compressed air right where it is needed.  It features a 3/8 NPT metal inlet to allow for increased air flow to the Super Air Nozzle of your choice and there are many configurations are available from stock.  It is constructed of a durable and robust cast aluminum body with an ergonomic and comfortable composite grip that allows for extended use without fatigue.

The Heavy Duty Safety Air Gun can be configured with extensions that are available in 6” increments up to 24” in length and 12” increments from 24” up to 72”.  Combine the extension with our optional Chip Shield for maximum operator safety and comfort.

 

Extension Tubes For Air Guns
Different Length Extensions For Every Application

 

Chip Shield
Chip Shields Offer Safety & Comfort For Operators

We offer a wide variety of nozzles to allow you to configure the Heavy Duty Safety Air Gun to you specific application.  EXAIR has a large selection of nozzles that are engineered to entrain surrounding air with the compressed air supply creating a synergistic blast that is very powerful.  Most importantly they operate much quieter than the limits of OSHA standard 29 CFR 1910.95(a) and can’t be “dead ended” therefore meeting OSHA standard 29 CFR 1910.242(b).

OSHA Chart
OSHA Maximum Allowable Noise Exposure

 

The EXAIR Heavy Duty Safety Air Gun is available in the configurations shown below or many others.  If you have an application you would like to discuss or to see how the Heavy Duty  Safety Air Guns will improve your process, give us a call, we are happy to help.

Heavy Duty Safety Air Gun Configuration Chart
Heavy Duty Safety Air Gun Sample Configurations

Steve Harrison
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