## What is Sound and Interesting Facts About Sound

In physics, sound is a wave of pressure. It occurs in a medium, which can be a solid, liquid or gas. Sound cannot travel through a vacuum, such as in space. The wave of pressure reaches our ears and causes the ear drum to vibrate, which then goes through a complex process to ultimately be perceived as audible sound.

There are several characteristics of sound waves that can be measured and help define the sound. A sound wave can be visualized as a repeating sinusoidal wave (see below), and can be described by these properties – frequency and wavelength, amplitude, and speed.

• Frequency is the number of cycles in 1 second, and is measured in Hertz (Hz)
• Wavelength is the distance over which 1 cycle occurs, and for audible sound is  between 17 m and 17 mm long
• Amplitude is the measure of its change over a single period, and normally a measure of sound loudness
• Speed is the distance traveled per unit time

The speed of sound in air can be found using the equation:  a = Sqrt (γ•R•T)

where for air:
γ = ratio of specific heats = 1.4,
R = gas constant = 286 m²/s²/K
T = absolute temperature in °K (273.15 + °C)

At room temperature, 22°C (71.6°F), the speed of sound is 343.8 m/s (760 mph)

Some interesting facts about sound:

• Sounds generally travels faster in solids and liquids than in gases.
• You can estimate the distance from a lightning strike by counting the seconds that pass between seeing the lightning flash and hearing the thunder.  Take this duration an divide by 5 to get the distance away, in miles.
• Humans normally hear sound frequencies between 20 Hz and 20,000 Hz.
• Sound waves above 20,000 Hz are known as ultrasound, and sound waves below 20 Hz are known as infrasound.
• Sound travel through water close to 4 times faster then through air.
• The sound of a cracking whip occurs because the speed of the tip has exceeded the speed of sound.

Sound that is too loud can be a problem. The Occupational Safety and Health Administration (OSHA) has set limits on the noise exposure that an employee can be subjected. Exceeding these values can cause permanent damage to your ears and cause noise induced hearing loss. So, knowing and reducing the sound levels within a manufacturing operation is important.

EXAIR has many products that can help reduce the sound levels in your processes.  With products such Air Knives, Air Wipes, Air Amplifiers, Air Nozzles and Jets, and Safety Air Guns, strong, quiet and efficient blowoff, drying, and cooling can be performed.

If you have questions about sound and keeping your sound levels in check or any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer
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## The Value Of A Pressure Regulator At Every Point Of Use

To understand the value of a having a Pressure Regulator at every point of use we should start with identifying the two types of Pressure Regulators, Direct Acting & Pilot Operated.  Direct Acting are the least expensive and most common (as shown above), however they may provide less control over the outlet pressure, especially if they are not sized properly.  However when sized properly they do an outstanding job.  Pilot Operated Regulators incorporate a smaller auxiliary regulator to supply the required system pressure to a large diaphragm located on the main valve that in turn regulates the pressure.  The Pilot Operated Regulators are more accurate and more expensive making them less attractive to purchase.  The focus of this Blog will be on the Direct Acting Pressure Regulator.

The Direct Acting Pressure Regulator is designed to maintain a constant and steady air pressure downstream to ensure whatever device is attached to it is operated at the minimum pressure required to achieve efficient operation.  If the end use is operated without a regulator or at a higher pressure than required, it result’s in increased air demand and energy use. To clarify this point, if you operate your compressed air system at 102 PSI it will cost you 1% more in electric costs than if the system was set to run at 100 PSI! Also noteworthy is that unregulated air demands consume about 1% more flow for every PSI of additional pressure.  Higher pressure levels can also increase equipment wear which results in higher maintenance costs and shorter equipment life.

Sizing of the Air Regulator is crucial, if it is too small to deliver the air volume required by the point of use it can cause a pressure drop in that line which is called “droop”.  Droop is defined as “the drop in pressure at the outlet of a pressure regulator, when a demand for compressed air occurs”.  One commonly used practice is to slightly oversize the pressure regulator to minimize droop.  Fortunately we at EXAIR specify the correct sized Air Regulator required to operate our devices so you will not experience the dreaded “droop”!

Another advantage to having a Pressure Regulator at every point of use is the flexibilty of making pressure adjustments to quickly change to varying production requirements.  Not every application will require a strong blast sometimes a gentle breeze will accomplish the task.  As an example one user of the EXAIR Super Air Knife employs it as an air curtain to prevent product contamination (strong blast) and another to dry different size parts (gentle breeze) coming down their conveyor.

EXAIR products are highly engineered and are so efficient that they can be operated at lower pressures and still provide exceptional performance!  This save’s you money considering compressed air on the average cost’s .25 cents per 1000 SCFM.

If you would like to discuss Air Regulators or quiet and efficient compressed air devices, I would enjoy hearing from you…give me a call.

Steve Harrison
Application Engineer
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## EXAIR Accessories – We’ve Got you Covered

When you work with us here at EXAIR, we strive to have all the ancillary items that you might need to make your installation a success, without having to find components at the last minute or perhaps using the wrong sized components. Each specific product line such as Super Air Knives or Line Vac air operated conveyors have specific accessories such as mounting brackets or plumbing kits which EXAIR has made to simplify the installation of those particular products. We also carry generalized accessories which work across all of the product lines so you do not have to use multiple vendors or purchase orders.

Silencing Mufflers – Per OSHA Standard 1910.95(a), a worker must not be exposed to sounds levels above 90 dBA for any eight hour shift of a 40 hour work week.  EXAIR offers several types of mufflers including – Reclassifying, Sintered Bronze, Straight-Through and Heavy Duty.  For reducing the noise associated with an EXAIR E-Vac Generator, Vortex Tube, Cabinet Cooler System, or the exhaust air from cylinders, valves and other air powered equipment, we’ve got a muffler that will help to keep the noise level at an acceptable level.

Solenoid and Manual Valves – The easiest way to reduce compressed air usage and save on operating expense is to turn off the compressed air to a device when it isn’t needed. EXAIR carries a wide assortment of solenoid valves, with offerings in the NEMA 4/4X classification, and supply voltages of 24VDC, 120VAC, and 240VAC.  We also have manual ball valves from 1/4 NPT to 1-1/4 NPT and a foot operated valve, with 1/4 NPT connections.

– To provide a great degree of flexibility for positioning an EXAIR Super Air Nozzle, Air Jets or Air Amplifiers, EXAIR offers several items.  The Swivel Fittings have 25 degree of movement from the center axis, providing a total of 50 degree of adjustability.  The position is locked in place and holds until adjustment is needed. For applications where frequent re-positioning of the air device is required, the Stay Set Hoses are ideal.  Simply mount the hose close to the application, bend it to the shape preferred, and because the hose has “memory”, it will not creep or bend.  Lastly, the Magnetic Bases are another option for flexible, movable installations.  The base has a on/off valve, and a powerful magnet to hold in any vertical or horizontal mounting arrangement.

Hoses – EXAIR can provide hoses for your application.  For the Line Vac air operated conveyor applications, we offer conveyance hose – a durable, clear reinforced PVC hose, in diameters of 3/8″ to 3″ ID, and lengths up to 50′. On the compressed air side, we can provide 12′ Coiled Hoses with 1/8, 1/4, and 3/8 NPT connections, and also 3/8″ and 1/2″ ID hose in lengths to 50′.

– Perhaps the most important accessories for use on a compressed air device are filters and regulators. Filtering the compressed air of dirt, debris, moisture and oil will help to prevent build up inside the EXAIR products, leading to longer service life, and less time spent cleaning, while providing optimum performance. Regulating the air pressure allows for tuning of the performance, using the proper amount of compressed air to obtain satisfactory results.

If you have questions regarding accessories for use with any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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## EXAIR Air Nozzle Provides Non-Marring Solution For Rotary Die Cutting

Die Cutting is a highly efficient means to produce large volumes of uniquely shaped parts while creating a low volume of wasted materials. There are several different ways to produce die cut parts with one of the more common being Rotary Die Cutting. A Rotary Die Cutter typically incorporates the material passing between a roller die cutter and a heavy roller anvil to cut the specific shape  then passes the material down a conveyor or feed line while retrieving the waste material in another collection device.

I recently worked with a customer who was starting to see a large volume of scrap in their vinyl and rubber parts die cutting process as the die cut parts themselves were getting stuck onto the rolling die cutter and weren’t getting grabbed by the conveyor rollers. To try and get the parts to eject from the cutter they installed a few 1/4″ open copper tube air lines running across the roller but were concerned with amount of air they were wasting and the high pitch noise levels of close to 100 dBA. They were also seeing some damage to the parts they were able to get loosened from the die as some of the parts would make contact with the pipe, causing a “blemish” on the part, ultimately failing inspection.

I recommend the customer use our Model # 1100-PEEK Super Air Nozzle. The Model # 1100 consumes only 14 SCFM of compressed air (at 80 PSIG), much less than a 1/4″ open pipe, tested at close to 140 SCFM @ 80 PSIG. This nozzle produces a low sound level of only 74 dBA falling well within the allowable noise exposure levels set forth by OSHA. In addition, the PEEK plastic construction provides a non-marring solution in the event one of the parts did make contact with the nozzle.

EXAIR offers a large selection of engineered air nozzles with varying airflow patterns, force, sound levels and materials of construction to meet a wide variety of application requirements. With help selecting the best solution or to discuss your particular application, please give us a call.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

## Safety, Efficiency, and Production Improvements

Last week, I received an email from a satisfied customer, after he had already purchased our product.  Come to find out this customer had not spoken to an application engineer during the planning stage to make their purchase. With our excellent resources listed at EXAIR.com, the customer was able to fulfill his application without even speaking to us. After his initial email of thanks, he also shared with me some details of his application that I want to share with you today.

The customer works as a machinist at a large aircraft part manufacturer. The parts require a very tight tolerance. A sample of each part needed to be gauged and measured in an automatic thread gauging machine or a coordinate-measuring machine (CMM). Their machining process required a water based flood coolant, so each part would be coated in water based coolant and chips, which needed to be remove before gauging. Before visiting EXAIR’s site, the company used a variety of homemade and commercial blow offs, as safety air gun tips. Here is a photo of (20) of the (25) nozzles the customer was using.

As you can see, the nozzles vary in design purpose, flow and safety. Most of the nozzles feature a cross drilled hole or a secondary escape path, but not all of the nozzles do. Any nozzle without a secondary relief port violates OSHA standard CFR 1910.242(b), so replacing some of the nozzles increased the safety in the plant. Secondly, these nozzles are wasteful in their use of compressed air because some were designed as liquid nozzles and have large exit holes. A hole that is 1/8″ in diameter at the nozzle outlet can consume up to 21.4 SCFM of compressed air at 80 PSIG. For comparison, the model 1103 Mini Super Air Nozzle with a 1/8″ NPT inlet will flow 10 SCFM at 80 PSIG, which would be a 53% compressed air savings. In 24 running hours, the 1103 nozzle will save 16,416 Standard Cubic Feet, which the plant spent \$4.10 for a standard industrial compressor to produce (The standard for compressed air cost is \$0.25 per 1,000 SCF). Replacing just one 1/8″ drilled hole with 1103 Mini Super Air Nozzle saves the aircraft company \$1,026 over 250 working days running 24 hours a day.

Neither of these were the real reason that the customer emailed to thank us though. He was actually an office employee just entering the work force.  Starting in June until after the company finally acquiesced to his request to buy a better, quieter nozzle near the end of July, he had left work needing an aspirin to relieve the headache he acquired due to the noise from these other nozzles. The nozzles the machining center had been using would create noise levels between 88-100 dBA at 80 PSIG of inlet pressure. For reference OSHA mandates that employees are required to wear hearing protection, if they are exposed to noise levels over 90 dBA over an 8 hour work day.  The employees doing the machining wear hearing protection, but the employees in the office were still exposed and affected by the noise level.  This is just one anecdotal example, but everyday more and more research shows that noise exposure has a negative effect on our health and productivity in the workplace.  If you are interested in more information here are some links to a number of studies/research – please read this, here or this.

Anyway, that’s enough of my soapbox. The company purchased 25 of EXAIR’s 1103 Mini Super Air Nozzles and utilizing the same guns they were currently using saw between a 10-15 dBA decrease in noise levels near the work stations. Here is a photo of one of their setups with the model 1103 installed on one of their current air guns.

We know that every time they squeeze that air gun trigger they will be using less compressed air than before, and we know they are now in compliance with OSHA. But the best benefit for EXAIR is we know that the engineer took the time to email us to thank us for taking away his headache everyday.  That’s enough for me.

Dave Woerner
Application Engineer
DaveWoerner@EXAIR.com
@EXAIR_DW

## EXAIR Super Air Knife: Reduce Cost, Reduce Noise, Increase Safety

This question from end user’s comes up again and again:

“I know EXAIR makes Air Knives. Do you have one for this application?”

We can answer, almost unequivocally, with a resounding “YES!” Whether we can meet the needs of the application with a stock product, or through manufacturing a specially made unit, we make every effort to provide the needed solution.

Case in point, in the application above, a specific length Air Knife was desired to remove debris from material as it goes into a processing chamber. The current setup (outlined in red)  uses drilled holes in a section of pipe which are costly, loud, and unsafe.

How costly, you ask? Our customer stated this knife was 100″ long with 3/32″ holes on 2″ centers (50 holes). EXAIR test results on 3/32″ drilled holes confirm 15 SCFM per hole at 80 PSIG inlet pressure. The customer also estimates this drilled pipe operates for a total of 1 hour every day, 250 days per year. Using \$0.25 per 1000 SCFM we can calculate the following:

• 50 holes x 15 SCFM = 750 SCFM at 80 PSIG
• 750 SCFM x 60 minutes per day = 45,000 SCF per day
• 45,000 SCF x 250 days = 11,250,000 SCF per year
• 11,250,000/1000 x \$0.25 = \$2812.50 cost per year

How loud, you ask? Our customer confirmed all personnel near the application were require to wear ear protection at all times. Though they were unable to provide a decibel (dBA) level, the need for hearing protection would indicate this pipe was operating in excess of 100 dBA.

How unsafe, you ask? Air can be dangerous when the outlet pressure of a hole is greater than 30 PSIG. In the event any of the holes were blocked by a hand or other body part, air may enter the bloodstream through the skin, resulting in serious injury. All of the Air Knives manufactured by EXAIR have been engineered for safety. They are all safe to be supplied with higher pressure compressed air and meet OSHA standard CFR 1910.242(b). Drilled holes in a pipe DO NOT MEET this OSHA standard.

Initially, discussions with this end user focused on a custom length, custom built Super Air Knife. Given the dimensions of the processing environment, we determined the desired length and the end user was thrilled we could not only make to their specifications, but offer 3 day delivery as well.

As the discussion carried on, we realized that the special length Super Air Knife, while applicable, was not a critical requirement for the application. With this new consideration, a stock length knife was chosen, and just like any stock EXAIR product, we had it on the shelf, ready to ship the same day.

This application highlights several benefits of the EXAIR Super Air Knife solution – compressed air savings, noise reduction, providing safety, and quick delivery. EXAIR Super Air Knives solve multiple problems for end users and OEM’s in a variety of applications.

Compressed Air Savings:

• 96″ knife with 2.9 SCFM per inch consumption at 80 PSIG = 278.4 SCFM at 80 PSIG
• 278.4 x 60 minutes per day = 16,704 SCF per day
• 16,704 SCF x 250 days = 4,176,000 SCF per year
• 4,176,000/1000 x \$0.25 = \$1044 cost per year
• \$2812.50 (drilled pipe annual air cost) – \$1044 (EXAIR 96″ Super Air Knife air cost) = \$1768.50 SAVINGS the first year!

Noise levels reduced to under 80 dBA.

SAFETY: EXAIR Super Air Knives meet the OSHA standard CFR 1910.242(b).

Switching this customer over to an engineered solution provided a win in these three important areas of any operation. If assistance is needed determining which Super Air Knife best suits your application, contact an Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

## Noise, Noise, Noise- Everywhere I go there is Noise

My son queried me as to why I drive without turning the radio on. Simply put, I savor the quiet time alone with my thoughts. Throughout the day I’m bombarded with noise from hawkers trying to sell me something, politicians barnstorming for my vote, and then there is all the noise from the workplace. Is it no wonder that I savor quiet time?

The salesmen and politicians you can turn off. Workplace noise on the other hand is something that is unavoidable, but, can minimized. In the process of reducing compressed air consumption, EXAIR products also reduce sound levels of compressed air blow offs. Their unique design draws in slower moving ambient air (3)  and forms an attenuating boundary layer over the high velocity compressed air (2). Even with 80 psig input (1) air, they operated at a surprisingly low 69 dBA sound level!

Are your ears ringing after a day at work? Do you want to reduce overall shop noise? Give an EXAIR application engineer a call 1-800-903-9247.

Joe Panfalone
Application Engineer
Phone (513) 671-3322
Fax   (513) 671-3363
Web: www.exair.com