Rotational molding: EXAIR Super Air Amplifiers compared to fans

Super Air Amplifier Family

A customer contacted EXAIR to find a better way to cool a die in a rotational molding facility.  Rotational molding, or Rotomolding, involves a heated hollow mold which is filled with plastic material. It is then slowly rotated (usually around two perpendicular axes), causing the softened material to disperse and cling to the walls of the mold. In order to maintain an even thickness throughout the part, the mold has to continue to rotate during the heating phase. After the desired timing sequence, the heating is turned off to allow the material to harden. 

This particular company was making plastic containers.  To try and improve the cycle rate between each container, they were using two fans (reference photo below) for cooling.  Time is money in this industry, and they wanted to target the fans to improve cooling.  They mentioned that water jackets for cooling would affect the life of the molds due to thermal shock.  So, they needed to cool with air; and EXAIR had a solution for them; the Super Air Amplifiers.

The Super Air Amplifiers as compared to fans are compact, easy to use, and very effective in cooling.  The capacity to cool is determined by the mass of air and the temperature difference. Since the mold is heated to 650oF (343oC) and the ambient air is 80oF (27oC), we have a good temperature difference for cooling.  For this application, I recommended to replace their fans with our model 120024 4” Super Air Amplifiers.  Each one can move 2,190 SCFM (6,1977 SLPM) of air while only needing 29.2 SCFM (826 SLPM) of compressed air at 80 PSIG (5.5 Bar). 

I also recommended to add one piece of a model 120022 2” Super Air Amplifier for cooling the inside of the mold.  Because the opening in the center of the mold is relatively small, a fan would take up most of the area.  Thus, not allowing the hot air to escape.  Since the 2” Super Air Amplifier is much smaller, they were able to place the air stream in the center allowing the hot air to escape around the edge of the hole.  With this combination, we were able to cool the mold 25% faster than the fans.  EXAIR did a comparison video between a Super Air Amplifier and a fan for cooling.  Watch it here.  

To expand on the comparison, EXAIR Super Air Amplifiers and electrical fans are designed to move air.  Fans use motors and blades to push the air toward the target.  There are mainly two types, centrifugal fans and axial fans.  The customer above was using axial fans.  The air enters from directly behind the fan, and the blades “slap” the air forward to the target. This creates a turbulent and loud air noise.  The EXAIR Super Air Amplifiers does not use any blades or motors to push the air.  They use a Coanda profile with a patented shim to create a low pressure to draw the air.   (You can read more about it here: Intelligent Compressed Air: Utilization of the Coanda Effect.)  So, they create laminar air flow which is much quieter. 

Super Air Amplifier – flow region

In physics, it is easier to pull than it is to push.  The same goes for moving air.  Fans are designed to “push” the air and the Super Air Amplifiers are designed to “pull” the air.  This method of pulling makes it simple to create a laminar flow in a small package which is more efficient, effective, and quiet.  With the patented shims inside the Super Air Amplifiers, they maximize the amplification by “pulling” in large amounts of ambient air while using less compressed air.  More air means better cooling.  If you want to move away from blower systems or axial fan systems to get better cooling, drying, cleaning, and conveying; you can contact an Application Engineer for more details about our Super Air Amplifiers. 

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

About EXAIR’s Deep Hole Vac-U-Gun

The Deep Hole Vac-u-Gun is a special iteration of the Vac-u-Gun, designed to provide a solution to the troublesome process of cleaning cavities and drilled holes.

The Deep Hole Vac-u-Gun is a low cost solution to quickly remove chips and debris from grooves and drilled holes where blow gun could create potentially hazardous flying debris. The Deep Hole Vac-u-Gun is simply positioned over the hole, and the trigger squeezed and then a small blow tube delivers a a stream of air to dislodge and lift the chips while the large suction tube vacuum them away. The operator is protected form flying debris since all chips and debris is contained within the clear suction tube. The device is capable of cleaning holes up to 1-1/4″ (32mm) diameter and 18″ (457mm) deep!

How does the Deep Hole Vac-u-Gun work?

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How the Deep Hole Vac-u-Gun Works

Compressed air, normally 80-100 PSIG (5.5 – 6.9 bar), flows through the inlet (1) into an annular plenum chamber (2) when the trigger is pressed. A small amount of air is injected into the blow tube (3) to provide agitation and lift to the chips or debris. The larger airflow is injected into the the throat of the gun through directed nozzles (4). The jets of air create the vacuum at the intake (5) which draws the material in and accelerates it through the unit. The chips, debris or other particulates can then be exhausted into a filter bag or hose attached to the Deep Hole Vac-u-Gun System.


We have found many applications where the Deep Hole Vac-u-Gun is beneficial- including removing chips and debris in:

Holes in fixtures, drilled plastics, T-slot groove cleaning , coolant evacuation from parts, woodworking, tapped holes, cavity evacuation, and many more!

There are many advantages to the Deep Hole Vac-u-Gun, and some are:

Low cost, no moving parts/maintenance free, durable die cast construction, eliminates shock hazard – no electricity, meets OSHA pressure requirements, safe operation – no flying chips, lightweight and portable, and quiet.

The Deep Hole Vac-u-Gun uses less compressed air than ordinary blow guns, and the amplified output flow is 12 times the air consumption rate.

Deep Hole Vac-u-Gun Specifications

Note that the Deep Hole Vac-u-Gun should not be operated without a filter bag or vacuum hose attached to the exhaust.

There are three (3) Deep Hole Vac-u-Gun System options-

Deep Hole Vac-u-Gun Systems

The Model 6094 is the Deep Hole Vac-u-Gun only.

The Model 6194 comes with a reusable bag and clamp for debris collection.

The Model 6394 comes with the reusable bag and a 10′ (3m) section of vacuum hose for transferring the debris to a collection point.

If you have questions about the Deep Hole Vac-u-Gun or any of the 16 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.

Jordan Shouse
Application Engineer

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Twitter: @EXAIR_JS

Tools Of The Trade: The Rotameter

EXAIR’s Free Efficiency Lab

One of the free services we offer to customers here at EXAIR is our Efficiency Lab. In case you are not familiar here is a brief synopsis. Speak with an Application Engineer about your existing compressed air blowoff/point of use product and that you would like to know how much air it consumes. Fill out the brief survey and send the product you use in to our facility. Let us perform tests on calibrated test equipment to determine the force, flow, and noise level. We will then issue you a report that states what the EXAIR model would best be suited (if applicable) as well as how much compressed air you will be able to save. Order the recommendation and start saving money.

To do these evaluations, we have to have calibrated equipment that is reliable and capable of handling vast range of products we may receive in. For this, we could use a Digital Flowmeter, in some cases that is what has to be done due to large flow rates. For the majority of these though we go old school. We utilize a piece of equipment called a rotameter.

A rotameter pairs nicely with a calibrated pressure gauge as well.

The float can be seen with graduated marks for readings. The taper of the chamber is not easily seen with the naked eye.

This is a device that is designed to measure the flow rate of a fluid within a closed tube. The inside diameter of the tube is varied which causes the float within the meter to raise or lower.  They are calibrated for a specific gas at a given pressure and temperature, most are calibrated for atmospheric conditions, 14.7 psi (1.014 Bar). The meter must be mounted vertically and this is not always best suited for industrial environments.

When testing products the compressed air within the meter is pressurized which means we have to correct the reading for the given pressure, if the temperature is outside of the calibration temp then we must also perform that correction. We do this using a table provided by the manufacturer of the meter or by using the calculations shown to get exact values that may be in between the pressures in the table.

Pressure Correction Table

 

This will allow us to then multiply the Correction Factor by the meter reading and calculate our corrected flow for the point of use device at a given operating pressure and temperature.

Temperature correction table

Knowing where the values that are measured and calculated come from add validity to the reports and understanding all of the variables that go into reading like this helps to better validate the cost savings that can be seen.

In a pinch, for a field estimation, we can also use these Correction Factors and determine an approximate consumption rate of a device that has been measured at a pressure such as our cataloged 80 psig (5.5 Bar). This can often be done on the fly to help determine the flowrates currently on a system. This can be helpful when troubleshooting, giving estimated simple ROIs, and help justify results and reasons for future purchases of engineered solutions.

If you want to discuss the Efficiency Lab or any of the math behind our calculations, contact any Application Engineer, we can all help out.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Happy Thanksgiving from EXAIR!

Well…here we are…we made it to the Holiday season of 2020.

Happy Thanksgiving from all of EXAIR to all of you!

Chances are that you may be feeling the same as we do – tired, disoriented, anxious, ready for “normalcy”, etc. A global pandemic, and the changes that have occurred because of it,  will have that effect on people. But then again here in the USA, that may be due to an election, but I digress…

Fortunately, Thanksgiving reminds us to take the time to recognize the good things that are happening around us, to be thankful and show gratitude. There have been many studies on gratitude and they have shown, at the least, there is a connection between gratitude and happiness. This Harvard Health article offers good insight about the power of gratitude and a good list of how we may begin to express gratitude ourselves, summarized below:

  • Write a thank-you note. –  It helps you and helps strengthen your relationships
  • Thank someone mentally. – If you don’t have time to write, do this.
  • Keep a gratitude journal. – Make it a habit and it turns into a journal.
  • Count your blessings. – Recognize good things that have happened
  • Pray. – Religious folk can use prayer to grow gratitude
  • Meditate. – you can meditate and focus on good things.

Today, I am thankful for music and its relaxing effect. I am grateful for the ability to go hiking and have the sun on my face.  Enjoy your days and Happy Thanksgiving.

The EXAIR team
Ph. 1-800-903-9247      1-513-671-3322
EXAIR.com 

EXAIR will be closed Nov 26-27, 2020 for Thanksgiving.