How to Pick the Right Atomizing Spray Nozzle

Atomizing spray nozzles atomize fluids with compressed air to create a fine spray in a variety of patterns for a variety of uses. They are commonly used to mark products, paint or coat, cool, reduce dust, lubricate and clean parts.

With the numerous types of Atomizing Nozzles, it can be challenging to sift through all the information. But with a few basic questions you can narrow down the right nozzle type for you and your application:

142 distinct models. 8 different patterns. Liquid flow rates from 0.1 to 303 gallons per hour. If you’ve got a spraying application, EXAIR has an Atomizing Nozzle for you!

Are you using a pressurized liquid feed? In some cases, a pressurized liquid source is not available for the nozzle, so you would have to rely on a gravity or siphon fed nozzle. While you lose the complexity of having a liquid pump pressurizing your liquid, you do have a few draw backs. Your siphon height is typically with in 36” so your liquid source has to be fairly close to your nozzle. Siphon fed nozzles are hard to turn off and on, they are best used for applications where you are continuously spraying a low viscosity liquid with a low gph.  

Internal Mix Atomizing Spray Nozzles

What is the viscosity of the fluid? Another deciding factor is the viscosity of the liquid you are spraying. Different nozzles are designed for different viscosity. For example, two of the main nozzle types are internal mix nozzles and external mix nozzles. They function just like they sound, internal mix nozzles mix the compressed air and liquid source inside the nozzle. And because of this they typically can not spray liquids over 300 cP. And because external mix nozzles mix the liquid and air outside the nozzle, they can handle liquids well above 300 cP.

What is the liquid flow rate in gallons per hour(gph)? Another factor in choosing the right nozzle is if your application has a set gph you are looking to achieve. Some nozzles are designed to flow more liquid then others. For example, the external mix nozzles inherently flow more liquid then the internal mix. As there is less restriction on the liquid flow. If you are looking for even higher gph you can source a liquid only atomizing nozzle, its going to give you a large bump in gph. But your droplet size will suffer with the liquid only nozzles.

Full Cone Liquid Only Atomizing Spray Nozzle

What droplet size are you looking for? Fine droplet sizes are one of the primary reasons atomizing nozzles are used. Benefits of small droplet sizes include even coating and liquid conservation. Internal mix nozzles will do the best at providing the smallest droplet size possible. While external mix and liquid only will give you larger droplet sizes but they will give you a larger gph some applications need.  

Should I use a No-Drip option?  The No-Drip option positively shuts off liquid flow when the    compressed air supply is shut off.  One benefit of this is appreciated in coating applications, where an errant droplet of liquid would mar an otherwise smooth, even coating.  Operationally, though, it also means you can precisely turn the liquid flow on & off, in short, quick bursts, up to 180 times a second.

No Drip External Mix

If you are in the need for a Liquid Nozzle to assist in your facility, please reach out! We have a team of application engineers waiting from 8AM – 5PM EST to help you size and fit a product to your specific application! 

Jordan Shouse
Application Engineer

Send me an email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

How to Add Sound Levels to Calculate Total Decibels of Noise

I recently wrote a blog about “Sound Power and Sound Pressure”.  I discussed the logarithmic equations around sound.  Today I will be discussing what happens when you have more than one sound source, as often heard within manufacturing plants.  Sounds can be added together to determine the overall sound level that your hear.  This is very important when it comes to minimizing hearing loss.

In looking at a single source of sound, sound pressure is created by the loudness of a noise.  The units are measured in Pascals.  The lowest pressure perceived by human hearing is 0.00002 Pa, and we can use this value as a reference point.  From sound pressures, we can arrive to a sound pressure level which is measured in decibel, dB.  This correlation between sound pressures and sound pressure levels are calculated by Equation 1:

 

L – Sound Pressure Level, dB

P – Sound pressure, Pa

Pref – reference sound pressure, 0.00002 Pa

As an example, the sound pressure from a passenger car as heard from the roadside is 0.1 Pa.  With Equation 1, we can get the following decibel level:

L = 20 * Log10 (0.1Pa/0.00002Pa) = 74 dB

Because human ears are sensitive to different frequencies, the sound pressure levels can be modified, or weighted, to indicate an effective loudness level for humans.  This adjustment is done in two different ways; A-weighting and C-weighting.  The C-weighting is for very loud noises with high peaks or sharp impacts like gunfire. The A-weighting is the most commonly used value as the sound pressure levels are adjusted by the frequency level.  For higher and lower frequencies, the change in the sound value is much greater than the mid-level frequencies that are within our hearing range.  Sound measurements for safety are measured in the A-weighted scale.  OSHA created a chart in the 29CFR-1910.95(a) standard that shows the noise levels over exposure times for an operator.  To use the OSHA chart accurately, the total noise level in dBA should be calculated.

OSHA Chart

To determine the total sound level, we can add all the sound pressure levels together by Equation 2:

 

 

Where L1, L2… represents the sound pressure level in dBA for each sound source.

As an example, a manufacturing plant had an operator using a machine that had four copper tubes to blow off a cutting operation (reference photo below).

 

The decibel level for a copper tube was measured at 98 dBA.  The total amount of sound that the operator was exposed to was determined by Equation 2 with four values.

L = 10 * log10 (109.8 + 109.8 + 109.8 + 109.8)

L = 104 dBA

In looking at the OSHA chart, the operator would only be allowed to operate the machine only a little over one hour without hearing protection.  In this same example, we replaced the copper tubes with an EXAIR Super Air Nozzle, model 1110SS.  The noise level for each nozzle is 74 dBA.  By replacing all four copper tubes with Super Air Nozzles, Equation 2 becomes:

L = 10 * log10 (107.4 + 107.4+ 107.4 + 107.4)    L = 80 dBA

The total sound level is now in accordance with OSHA regulations for the operator to work all 8 hours at the machine without hearing protection.

A commonly used acronym in hearing safety is NIHL, or Noise Induced Hearing Loss.  To keep your operators safe and reduce NIHL, it is important to measure the total sound level.  As a protocol in safety, it is a requirement to use engineering standards before purchasing personal protective equipment or PPE.  For the customer above, they followed that protocol with our Super Air Nozzles. 

If you need to reduce noise levels in your facility by engineering standards, EXAIR offers a large line of blow-off products that can meet the safety requirements.

Jordan Shouse
Application Engineer

Send me an email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

 

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.
7179304430_8101287900_c
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

Heavy Duty Safety Air Guns when Maximum Force is Needed

EXAIR’s Heavy Duty Safety Air Gun is designed to provide powerful blasts of compressed air for use in rugged, industrial environments. With a larger 3/8 NPT air inlet compared to our other Safety Air Guns, it allows for higher force and flow values. It comes with a durable cast aluminum body and ergonomic composite rubber grip. The wide curved trigger allows for continuous use for hours without operator’s experiencing fatigue.Heavy Duty Safety Air Gun Configuration Chart All of EXAIR’s Safety Air Guns come with an engineered compressed air nozzle at the tip. This allows you to remain OSHA compliant while still getting the force you need to get the job done. EXAIR’s Super Air Nozzles utilize the coanda effect to entrain large amounts of ambient air from the environment. This ambient air mixes with the primary air stream and is projected towards the target with more force and flow than the supplied compressed air could deliver alone.  Each of the Safety Air Guns is available with extensions fully assembled ranging from 6”-72”. You can simply add a “-“ and the required length, in inches, to the end of any Safety Air Gun Model number. HD SAG Chip Shield and Extensions In addition, they’re also available with a Chip Shield to prevent any chips or debris from coming back into the faces of your operators. Effective chip guarding is another component of OSHA 1910.242(b) in addition to the concerns of dead-end pressure. To add a Chip Shield onto the gun as well, a “-CS” to the standard Model number. For example, a Model 1310-12-CS would be a 1310 gun with 12” extension and a Chip Shield installed. If the application involves blowing off metal chips or shavings, your operators will certainly appreciate this Chip Shield preventing the debris from blowing back all over them.
Chip Shields
Optional Chip Shield
With EXAIR’s Heavy Duty Safety Air Gun, you can still achieve the high forces required for tough applications without the risk of injuries to personnel. It’ll also keep you safe from any fines associated with an unannounced OSHA visit. Do yourselves and your operators a favor and get one on order today! Jordan Shouse Application Engineer Send me an email Find us on the Web  Like us on Facebook Twitter: @EXAIR_JS