Managing Pneumatic Sound

I recently took my daughter to a basketball game to watch Xavier University’s Lady Musketeers play. Due to Covid the arena felt empty and we could hear the players on the court and also the the coaches from the opposite side. If this was a regular season game we could barely hear ourselves let alone the teams and coaches. The obvious reason why there was not much noise is that there wasn’t much of a crowd and the crowd makes a lot of sound. So, what is sound?

Sound can be defined as “vibrations that travel through the air or another medium and can be heard when they reach a person’s or animal’s ear”. Sounds hit our ears at different pressure levels depending on its strength (“loudness” or volume) and is measured in decibels (dB).

When sound travels and comes into contact with a surface, a portion will be absorbed and another portion will be reflected. Manufacturing environments obviously can be the source of a lot of sound and personnel near the sources should be protected as much as possible. One extremely effective way to do this is to substitute a loud noise source with a quieter one or remove the source all together. PPE can be effective but is much less reliable due to people forgetting to use PPE, using PPE improperly or even deciding for themselves they do not need it.

To substitute or eliminate means something like the strategic placement of air compressor which is not near personnel or recognizing the type of product you choose to use is vital to sound management and the health and safety of people working near the point of use. Many EXAIR products can help you reduce the sound level of your current point-of-use compressed air by replacing commercial air nozzles, open pipes and homemade blowoff solutions with our Engineered Air Nozzles, Safety Air Guns, Air Amplifiers, or Super Air Knives. These products are all designed to minimize compressed air noise and can contribute to lowering the overall noise exposure of your personnel. The additional benefit is that you customers will also typically see a reduction in air consumption which saves money on generating compressed air.

EXAIR’s Digital Sound Level Meter is a tool used to identify and quantify the particular noise levels within an area. The source of loud noises can be quickly identified and isolated so corrective measures can be implemented.

Compressed air noise levels often exceed OSHA (Occupational Safety and Health Administration) noise level exposure requirements. EXAIR pneumatic products meet or exceed the OSHA Standard 29 CFR-1910.95(a) and can be used to reduce sound levels in your compressed air environment.

EXAIR has has many engineered compressed air products that can help reduce your sound levels. Our Application Engineers are ready and eager to help assist your sound level decrease projects. Please contact us at www.EXAIR.com so we can be a vital part of your successful sound reduction program.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK

Compressed Air Super Air Knife vs. Blower-type Air Knife for Plastic Film Manufacturing

A plastic company produced many kinds of films and sheets.  They were having issues with one particular film, an OPS (Polystyrene) film which was 0.012” (300 microns) thick and 30” (762mm) wide.  As the material was extruded into a flat sheet, they would run it over a cold roll drum (Reference photo above).  The cold drum is a large cylinder that has chilled water running through it.  To keep the sheet on the surface of the cold drum, they used a blower air knife system.  With the blower air knife, they were having variation in thickness as well as stretch marks.  They heard about the EXAIR Super Air Knife, and they wanted me to do a comparison.  I was glad to compare the EXAIR 110230 30” Super Air Knife Kit to their blower-type air knife system.

Super Air Knife Kits include a Shim Set, Filter Separator, and Pressure Regulator.

  1. “Stretch” marks on the plastic film:
    • Blower System – Hot air is generated by the blower system. When the hot air hits the cool surface, it would cause an uneven hardening of the material, causing stretch marks.
    • Super Air Knife – It has a 40:1 amplification ratio. That means that 40 parts of the ambient air is entrained with 1 part of compressed air.  Being that the ambient air is much cooler than the hot air from the blower system, it actually aides in cooling.  There is no thermal shock to the sheet material, and hardening is consistent and faster.
  2. An even force across the plastic film:
    • Blower System – Their design had one 4” (102mm) line feeding into the side of the blower air knife. This would cause two issues for an even force.  As the velocity of the air hits the opposite side of the knife, the closed end, a turbulent air flow is developed.  Also, there would be a slight negative pressures at the entrance caused by the velocity of the air entering.  This chaotic turbulent flow caused an uneven force on the surface of the film.
    • Super Air Knife – The flow that is delivered from the Super Air Knife is laminar. This means that the force and velocity is consistent across the entire length, even on the target.  With this even force, the film was held evenly and securely on the cold drum.  With a filter, shim set, and regulator that is included in the kit, the force can be easily adjusted to the perfect requirement.
  3. Maintenance requirements:
    • Blower System – Preventative maintenance is a requirement. The blower filters have to be changed regularly, and the mechanical and electrical components have to be checked.  This requires downtime to the system.  In addition to this, blower motors are mechanical devices.  The bearings will wear and the motor will fail.  If a mechanical failure does occur, the downtime can cost days of operation.  These items should be checked quarterly as a PM which increases the cost of ownership.
    • Super Air Knife – No moving parts to wear out. The only maintenance would be to change the compressed air filter once a year.  There is no worry about catastrophic failure.
  4. Noise levels:
    • Blower System – With the blower motor and turbulent air flow, the system makes a lot of noise. They have a sound level near 93 dBA which would need PPE for nearby operators.
    • Super Air Knife – These units are very quiet. At a pressure of 100 PSIG (6.9 bar), the sound level is only 72 dBA.  No additional cost for PPE or the constant nagging disturbance of loud noises.
  5. Compact Design:
    • Blower System – The foot print of the blower is large and it takes up much floor space. The 4” (102mm) duct has to be ran to an oversized air knife (Reference photo below).  With the turbulent flow, the blower air knife has to be mounted close to the film surface.  So, it can make it difficult to optimize the placement.
    • Super Air Knife – With the compact design, the Super Air Knife has a large force in a small package. The model 110230 Super Air Knife has a footprint of 1 ¾” X 1 ½” X 30” long (44 X 38 X 762mm respectively) with only two ¼” NPT compressed air lines feeding it.  The force measurement is the same from 3” (76mm) to 12” (305mm) away from the surface; giving flexibility in placement.

When it comes to using the EXAIR Super Air Knives, it has many benefits over the blower-type air knives.  We can even include the initial purchase price in which the Super Air Knife would be about 1/10 the cost, and the company was able to increase production with a cooler blowing device.  They were delighted to remove the large blower-type system and replace it with a simple Super Air Knife.  If you would like to discuss the advantages of the Super Air Knife against a blower system, an EXAIR Application Engineer will be happy to assist.

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

Video Blog: Selecting the Right Air Knife

The following short video explains the differences between the three styles of Air Knives offered by EXAIR – The SuperStandard and Full-Flow

Please reach out to myself or one of our application engineers if you need help figuring which Air knife suits your application best!

Jordan Shouse
Application Engineer

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

 

Compressed Air in Farming and Agriculture

I used to help my father-in-law around his farm and this city boy had his eyes opened when he realized it was more than shovels, tractors and livestock. Agriculture is vital for human existence and has become far more advanced over the centuries with a continual thirst for efficiency and technology. Agriculture is just like many other industries looking for continued ways to increase yield, improve quality, maximize labor and improve technology.

EXAIR has many products used in the agriculture and food processing industries. The following details a few example by product line how we can influence efficiencies and quality of products:

Super Air Knife drying fruits and vegetables

Super Air Knives:

EXAIRs Super Air Knives are have ben used to help harvest apples and peaches. In this case they use our Super Air Knives to dry and blow off the fruit after the rinsing process just before the waxing process then again after waxing to blow off any remaining debris or moisture from the fruit before being packed.

A processing company using the Super Air Knife to clean a conveying belt equipped with a weighing system. Before the installation of the the Super Air Knife some of the cut vegetables being weighed would stick to the belt. Their solution was to clean the conveyor belt with EXAIR’s Super Air Knife to ensure continuous operation of the weighing and packaging systems.

Super Air Nozzles:

An onion farmer used EXAIR’s Model 1100 Super Air Nozzle to blow loose onion skins from the onions before packaging to improve the aesthetics to the customers.

Line Vacs:

A food packaging company repackages banana peppers from 55 gallon drums to 1 and 5 gallon containers using our Model 6066 3″ Stainless Steel Line Vac.

Using EXAIRs Model 150200 2″ Heavy Duty Line Vacs a feed stock manufacturer conveys various grains and feed stock simultaneously to a mixer which blends the ingredients. This reduced their blend time by 50%.

A grain processor used Model 142200 aluminum threaded Line Vac to convey small amounts of corn meal into a hopper which feeds into their inspection process.

A company producing worm eggs encapsulated in water soluble wax sold to farmers to enhance soil conditions. They eliminated a hand operation using Model 6081 1″ Aluminum Line Vac  to convey the worm eggs from one classifier to another.

EXAIR has several applications using Atomizing Spray nozzles to add moisture in growing environments . Greenhouses use our Atomizing spray nozzles to control humidity in the air and keep their soils moist to maintain optimal growing environments.

There are many other applications using compressed AIR on farms such as filling tires, cleaning equipment, blowing out water lines and more. Technology drives labor savings and improved quality prototypes are being designed and tested to use compressed air using drones to shoot pods filled with seeds, fertilizer and other nutrients into the soil. EXAIR will remain a strong influence in the growth of compressed air products helping to reduce the carbon footprint, enhance efficiencies and improve cost and quality within the agriculture and food processing industries.

If you have an application and you would like to talk please contact me or any of our qualified Application Engineers at 800.903.9247 and we will gladly help with our best recommendations.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK