Understanding Noise: Sound Power Vs. Sound Pressure

Sound Power and Sound Pressure have been covered a few other times here on the EXAIR Blog. Once here by Brian who made the visual correlation in regards to a speaker and a musical instrument. And here by Russ who breaks down how you calculate sound power level with the below equation!
Sound Power Equation
too lou Sound Power Level Equation
All machines generate sound when they are in operation. The propagated sound waves cause small changes in the ambient air pressure while traveling. A sound source produces sound power and this generates a sound pressure fluctuation in the air. Sound power is the cause of this, whereas sound pressure is the effect. To put it more simply, what we hear is sound pressure, but this sound pressure is caused by the sound power of the emitting sound source. To make a comparison, imagine for example a simple light bulb. The bulb’s power wattage (in W) represents the sound power, whereas the bulb’s light intensity represents the sound pressure.
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Light Bulb
Sound power does not generally depend on the environment. On the contrary, the sound pressure depends on the distance from the source and also on the acoustic environment where the sound wave is produced. In the case of indoor installations for example, sound pressure depends on the size of the room and on the sound absorption capacity of the surfaces. For instance, say the room walls don’t absorb all the sound but reflect parts of it, then the sound pressure will increase due to the so called reverberation effect. (reverberation time is broadly defined as the time it takes for the sound pressure to reduce by 60 dB after the sound emitting source has been shut off). OSHA puts the following limits on personnel exposure to certain noise levels:
Working in areas that exceed these levels will require hearing protection.
EXAIR’s line of Intelligent Compressed Air Products are engineered, designed, and manufactured with efficiency, safety, and noise reduction in mind.  If you’d like to talk about how we can help protect you and your folks’ hearing, call us. Jordan Shouse Application Engineer Send me an email Find us on the Web  Like us on Facebook Twitter: @EXAIR_JS Light Bulb image courtesy of  josh LightWork  Creative Commons License

Benefits and Options for Safety Air Guns

EXAIR Safety Air Guns are available, from stock, with Chip Shields.

Throughout industrial environments, there are often manual cleaning or blow-off applications that are performed with compressed air. These operations vary in frequency, intensity, and how critical to the operation they may be.

When it comes to OSHA standards and comfort of operators, many of the solutions found in manufacturing do not meet the standards and are dangerous to operators.

This is where EXAIR steps in and focuses on the end application while coupling a high performing engineered solution with an ergonomic and safe handheld safety air gun. In other words, EXAIR safety air guns are safe, easy to use, and typically reduce compressed air consumption. Currently, we offer four types of handheld safety air guns.

The VariBlast Compact Safety Air Gun:

This is my personal favorite in our current lineup of safety air guns.  The compact size fits comfortably in the hands of operators. The multi-finger trigger with patented VariBlast function is easily controlled for extended periods of time. The VariBlast Compact Safety Air Gun also has two compressed air inlets. This gives the ability to plumb compressed air into the bottom 1/4″ FNPT port or the top 1/4″ FNPT which a safe way to run air hoses for virtually any work station. The 1/8″ NPT outlet permits enough airflow to operate up to our High Power 1″ Flat Super Air Nozzle all the way down to our Atto Super Air Nozzle.  The patented design also delivers variable flow from any of the nozzles attached to operate anywhere from a gentle breeze up to a forceful blast.

The VariBlast Compact Safety Air Gun can also be coupled with an extension up to 72″ lengths as well as the Chip Shield to meet or exceed OSHA standards for compressed air cleaning.

The Soft Grip Safety Air Gun:

This safety air gun is the next step up in size and options as far as force and flow of compressed air go. The four-finger trigger and integrated hook design make this safety air gun ideal for industrial environments where a little more force is needed from the air to blowoff products.  The Soft Grip Safety Air Gun offers a 1/4″ NPT female thread inlet on the bottom and is available with up to an 1106 1/2″ Large Super Air Nozzle on the discharge.  This will deliver up to 60 SCFM of compressed air and provide 3.3 lbs of force from 12″ away.  The Soft Grip Safety Air Guns are also available with up to a 72″ extension and a chip shield.

Heavy Duty Safety Air Guns

Heavy Duty Safety Air Gun with extension.
eg. 1350-72

The Heavy Duty Safety Air Gun is even more robust than the Soft Grip Safety Air Gun and showcases a 3/8″ NPT female inlet to provide enough airflow to operate up to our model 1106 Large Super Air Nozzle as well to provide 60 SCFM  of airflow and provide 3.3 lbs of force.  Extensions are available in lengths up to 72″ with the addition of the chip shield.

 

Super Blast Safety Air Guns

Super Blast Safety Air Gun makes short work of large area cleanup.

The final Safety Air Gun offered is the Super Blast Safety Air Guns which are offered in four different NPT sizes. Ranging from 3/8″ NPT up to 1-1/4″ NPT and flows and forces from 56 SCFM providing 3.2 lbs of force up to 400 SCFM giving off 23 lbs of force.  These are available with an optional 3′ or 6′ extension to provide a robust blast for the heaviest cleaning or blowoff operation.

No matter the application, or amount of debris, EXAIR Safety Air Guns have an option that will fit the need while providing a safe and efficient solution. If you would like to discuss these further, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Compressed Air and Pneumatic Systems

Compressed Air Pipe

Compressed air is used to operate pneumatic systems in a facility, and it can be segregated into three main sections; the supply side, the demand side, and the distribution system.  The supply side is the air compressor, after-cooler, dryer, and receiver tank that produce and treat the compressed air.  They are generally found in a compressor room.  The demand side is a collection of devices that will use the compressed air to do “work”.  These pneumatic components are generally scattered throughout the facility.  To connect the supply side to the demand side, a distribution system is required.  Distribution systems are pipes or tubes which carry compressed air from the air compressor to the pneumatic devices.  The three sections have to work together to make an effective and efficient system.

Compressed air is a clean utility that is used in many different ways, and it is much safer than electrical or hydraulic systems.  But most people think that compressed air is free, and it is most certainly not.  Because of the cost, compressed air is considered to be a fourth utility in manufacturing plants.  For an electrical motor to reduce a volume of air by compressing it, it takes roughly 1 horsepower (746 watts) to compress 4 cubic feet (113L) of air every minute to 125 PSI (8.5 bar).  With almost every manufacturing plant in the world utilizing air compressors larger than 1 horsepower, the amount of energy needed is extraordinary.

Let’s determine the energy cost to operate an air compressor by Equation 1:

Equation 1:

Cost = hp * 0.746 * hours * rate / (motor efficiency)

where:

Cost – US$

hp – horsepower of motor

0.746 – conversion KW/hp

hours – running time

rate – cost for electricity, US$/KWh

motor efficiency – average for an electric motor is 95%.

As an example, a manufacturing plant operates a 100 HP air compressor in their facility.  The cycle time for the air compressor is roughly 60%.  To calculate the hours of running time per year, I used 250 days/year at 16 hours/day.  So operating hours equal 250 * 16 * 0.60 = 2,400 hours per year.  The electrical rate for this facility is $0.10/KWh. With these factors, the annual cost to run the air compressor can be calculated by Equation 1:

Cost = 100hp * 0.746 KW/hp * 2,400hr * $0.10/KWh / 0.95 = $18,846 per year in electrical costs.

Filters and Regulator

If we look at the point-of-use or demand side, the compressed air is generally conditioned to be used to run and control the pneumatic system.  The basic units include filters, regulators, and lubricators.  The filters are used to remove any oil, water, vapor, and pipe scale to keep your pneumatic system clean.  They fall into different types and categories depending on the cleanliness level required.

Filter Separators are more of a coarse filtration which will capture liquid water, oil, and particulate.  The Oil Removal Filters are more of a fine filtration which can capture particles down to 0.03 micron.  They are also designed to “coalesce” the small liquid particles into larger droplets for gravity removal.  One other group is for removing oil vapor and smell.  This type of filter uses activated charcoal to adsorb the vapor for food and pharmaceutical industries.  Filters should be placed upstream of regulators.

Pressure Regulators change the pressure downstream for safety and control.  Pneumatic devices need both flow and pressure to work correctly.  The lubricator, which is placed after the Regulator, helps to add clean oil in a compressed air line.  Air tools, cylinders, and valves use the oil to keep seals from wearing with dynamic functions.  Once the compressed air is “ready” for use, then it is ready to do many applications.

For EXAIR, we manufacture products that use the compressed air safely, efficiently, and effectively.  EXAIR likes to use the 5-C’s; Coat, Clean, Cool, Convey and Conserve.  We have products that can do each part with 16 different product lines.  EXAIR has been manufacturing Intelligent Compressed Air Products since 1983.  Compressed air is an expensive system to operate pneumatic systems; but, with EXAIR products, you can save yourself much money.  If you need alternative ways to decrease electrical cost, improve safety, and increase productivity when using compressed air, an Application Engineer at EXAIR will be happy to help you.

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

Protecting Employees With PPE vs. Engineered Controls and Substitution

PPE has been a hot topic and new buzzword for a lot of people and throughout many industries over the past 6 months, and rightfully so. When you look at manufacturing though, PPE has been a buzzword for decades. We continue to evolve processes, equipment, and wearables to ensure the safety of operators.  It all boils down to the fact that PPE and the equipment have to be used, and used appropriately in order to be effective.

When reviewing the CDC’s guides for Hierarchy of Controls the least effective method to protect workers is PPE that they must implement and wear/use properly. The fact is, PPE is one of the cheaper entry levels to get to safe working conditions upfront. However, the cost of ownership can quickly surpass more effective methods of providing safe conditions for operators, such as installation of engineered controls or even substituting the hazard w/ engineered solutions.

CDC’s Hierarchy of Controls

 

So what exactly does that mean to the people on the shop floor? Rather than having to grab a set of pinch and roll earplugs every day on the way through the breezeway to get to the production line, permanently installing quiet products like Super Air Nozzles or Super Air Knives in place of open-ended pipes and drilled pipe blowoffs could eliminate the need for these uncomfortable nuisances. And reliance on personnel to use them correctly, or use them at all is a gamble.

How else can EXAIR help in this pursuit of operator safety and happiness? We offer a free service, the EXAIR Efficiency Lab, which will test your current blow-off products for force, flow, air consumption and noise level. We then recommend an engineered solution if we can improve upon those parameters (spoiler alert, we can) that will meet or exceed OSHA standards for dead-end pressure and allowable noise level exposure.

EXAIR’s Free Efficiency Lab

For this example, installing a quiet product to aid in lowering noise levels can create an environment that no longer needs PPE for protecting personnel. The fix is permanent and eliminates forgotten, lost or broken PPE and the expensive associated with them.

If you would like to discuss any of these options further, please let me know.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF