## 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)

• 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
Send me an email
Find us on the Web

## EXAIR Products: Silencing Mufflers Overview

OSHA Standard 29 CFR 1910.95(a), relating to permissible noise exposure levels, states that when employees are subjected to sounds in excess of 90 dBA, some type of control should be used to reduce the sound level. In an industrial setting, it’s very common to find the exhausting air from air operated devices such as actuators, diaphragm pumps or cylinders for example, to produce sound levels well above the allowable limits set forth in the Standard. EXAIR offers a variety of different Silencing Mufflers that help to reduce this  noise level, while also increasing operator safety.

EXAIR’s Reclassifying Mufflers offer noise reduction up to 35 dB and are available in sizes ranging from 1/8″ to 1″ NPT. These types of mufflers are often considered”dual-purpose” as they not only reduce the noise level but also remove oil from the exhaust airflow by incorporating a removable filter element.  The exhausting oil mist is reduced from 50 PPM (parts per million) to only 0.015 PPM, when the device is operated at 100 PSIG. In addition, there is a bowl on the bottom to capture any residual oil and a 1/4″ tube adaptor to allow for easy draining.

Sintered Bronze Mufflers are a relatively low cost option, commonly used with air cylinders as they can be installed quick and easy. We offer 1o different sizes, ranging from #10-32 for small installations, up to 1-1/2″ NPT for larger scale applications. The noise reduction depends on the size of the muffler and back pressure, which can occur from dirt or particulate clogging the muffler, restricting the exhausting airflow from passing through the porous sintered bronze.

Our Straight Through Mufflers are made of corrosion resistant aluminum and are lined with a sound absorbing foam, capable of reducing noise levels up to 20 dB. We offer 3 different sizes, 1/4″, 3/8″ and 3/4″ NPT, with a male thread on one end and female thread on the other. We incorporate this muffler design into our Cold Guns and Adjustable Spot Coolers and they are commonly used with our Vortex Tubes, Cabinet Cooler® Systems and E-Vac® Vacuum Generators as well.

Lastly, the Heavy Duty Mufflers feature an internal, 50 mesh stainless steel screen, to protect against contaminants in the airflow,  and a corrosion resistant aluminum outer shell. In most cases, the sound reduction can be as high as 14 dB and we offer 2 different sizes, 1/4″ and 3/8″ FNPT. These types of mufflers are regularly used on the hot air exhaust of our Vortex Tubes.

For help with product selection or to discuss a particular process, please contact one of our application engineers at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

## Not All Compressed Air Guns Are The Same

If you work in an industrial plant or manufacturing environment, chances are you use some type of compressed air gun for cleaning parts, work areas, etc. Many air guns purchased through large industrial suppliers are a common choice due to the cost of the gun but as the saying goes – “you get what you pay for”. These types of guns may be cheap to purchase but they are also made cheap and have parts that can break easily, like the trigger or nozzle. In many cases, the nozzles on these guns are also in violation of OSHA requirements, producing dangerous discharge pressures and loud noise levels, which can lead to costly fines or potentially deadly injuries.

EXAIR offers 5 different styles of Safety Air Guns that not only eliminate these concerns, but also provide a more efficient operation, which can reduce energy costs. All of our Safety Air Guns are fitted with our engineered Air Nozzles  which meet OSHA Standard 1910.242(b) for 30 PSI dead end pressure, as they provide a relief or safe path for the air to exit if the nozzle were to be blocked or pressed against an operator’s body so the exiting air pressure will never reach 30 PSIG. They are also engineered to entrain surrounding air across the profile of the nozzle, which produces a smoother airflow, ultimately reducing wind shear, resulting in much lower sound levels, meeting OSHA Standard 29 CFR 1910.95(a).

The Precision Safety Air Gun body is made of a durable high impact, glass reinforced nylon, providing for a lightweight, ergonomic operation. These guns feature a curved extension, ideal for delivering a powerful stream of air in hard to reach areas, like clearing debris from drilled holes. All of the nozzles used with these units are either 316ss construction for durable, corrosion resistance or PEEK plastic for non-marring applications. The air inlet is 1/4 FNPT and there is a convenient hanger available for safe storage.

Our NEW VariBlast Compact Safety Air Guns are ideal for light to medium duty processes, featuring a variable flow trigger to achieve different force levels ranging from 2.0 ounces up to 1 pound, depending on the nozzle. The body is cast aluminum and there are (2) 1/4 FNPT air inlets available, 1 on the bottom and 1 on the back of the gun, as well as a storage hanger, for easy installation. Nozzles are available in zinc aluminum alloy, 303ss, 316ss and PEEK plastic. These guns are available with aluminum extensions from 6″ up to 72″.

The Soft Grip Safety Air Guns are commonly used in long-term use applications as they feature a comfortable grip and long trigger which helps to reduce hand and finger fatigue. The cast aluminum construction is well suited for more rugged environments and again, features a hanger hook. These guns can be fitted with aluminum, stainless steel or PEEK plastic to meet the demands of a variety of applications and are available with 6″ – 72″ aluminum extensions for extra reach or Flexible Stay Set Hoses , allowing the user to aim the airflow to a specific target area. The air inlets for these guns are going to be 1/4 FNPT.

EXAIR’s Heavy Duty Safety Air Guns deliver higher force and flows than other air guns, as these units feature a 3/8 FNPT air inlet, which maximizes the compressed air flow to the engineered Super Air Nozzle. Like the Soft Grip, the durable cast aluminum body is designed for use in tough industrial processes, and the ergonomic and comfortable trigger are ideal for hours of use. Aluminum extension are available, again in lengths from 6″ up to 72″, but feature a larger diameter for optimal flow and superior durability.

The Precision, VariBlast, Soft Grip and Heavy Duty Safety Air Guns are ALL available with an optional, polycarbonate Chip Shield to protect personnel from flying chips and debris, further meeting OSHA Standard 1910.242(b) for the safe use of compressed air.

Lastly we offer our Super Blast Safety Air Guns. The Super Blast Safety Air Guns are ideal for wide area blowoff, cooling or drying a part, as well as long distances. They feature a comfortable foam grip and spring loaded valve that will shut off the airflow if the gun is dropped. These units use our larger Super Air Nozzles and Super Air Nozzle Clusters, providing forces levels from 3.2 lbs. up to 23 lbs. Depending on which nozzle is fitted on the assembly, air inlets will range from 3/8 FNPT up to 1-1/4 FNPT. Aluminum extensions are available in 36″ or 72″ lengths.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

## 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

Send me an email
Find us on the Web