Sometimes you need more power.  I received a phone call from a bottling facility that was currently using a blower style type of air knives.  They increased their production rate from 220 bottles/min to 300 bottles/minute, and they started to see issues in the labeling process.  Their operation consisted of a wash cycle, rinse cycle, drying cycle, then labeling.  They determined that the bottles were not getting dry enough during the drying cycle before the labels were applied.  They had a VFD (Variable Frequency Drive) for the blower system, and they reached the maximum rate.  Still the bottles were not getting dry enough to allow the label to stick to the surface properly.  This meant that they would have to increase the size of their blower system.  With the capital cost of a blower system, they decided to call EXAIR to see if we could help them with the drying application.

Compressed air is the best way for establishing a strong blowing force.  Instead of air pressures in the range of inches of water, the compressed air system can generate over 40 times the amount of pressure than a typical blower system.  EXAIR products uses this power of the compressed air to give you a wide range of blowing forces for drying, cooling, or moving products.  For the above application, I recommended two model 110212 Super Air Knife kits.  The kit includes the Super Air Knife, a filter, a regulator, and a shim set.  They mounted one knife on each side of the bottles to blow off and remove the liquid after the rinse cycle.  Even at the increased bottle speeds, the EXAIR Super Air Knives had no issues in keeping the bottles dry.  With the regulator and the shim, it was easy for them to dial in the correct amount of force without using excess compressed air.  The labels remained glued and the bottling process ran smoothly.  Because the company was impressed by the Super Air Knives, they wanted to comment on the comparisons between the blower knife and the Super Air Knife.

1. Cost:
   1. Blower System – The reason for contacting EXAIR. Blower-type air knives are an expensive set up.  They require a blower, ducting, and a knife.  To have any flexibility, a control panel with a VFD will be needed.
   2. Super Air Knife – It is a fraction of the cost. With their system, we were roughly 1/10 the cost; even with the kit.  No capital expense report would be needed for the two air knives.
2. Installation:
   1. Blower System – They stated that it took them a week to install the entire system before they were able to operate. They had to run electrical wires, controls, ducting, and they even had to change the conveying system slightly to accommodate the blower size.
   2. Super Air Knife – They mounted the filter and the regulator on the conveyor, and ran tubing to the Super Air Knives. Even with a fabricator making a bracket to fit into their system, they had the system up and running is less than two hours.
3. Size:
   1. Blower System – The foot print of the blower is large and it takes up floor space. The 3” ducting had to be ran to an oversized air knife.  With the congestion of the bottle system, it made it difficult to optimize the position and the blowing angle to adequately dry the bottles.
   2. Super Air Knife – With the compact design, the Super Air Knife packs a large force in a small package. It has a footprint of 1 ¾” X 1 ½” X 12” long.  The air knife only required a ¼” NPT compressed air line to supply the compressed air.  It opened up the floor space as well as the bottling area.
4. Maintenance:
   1. Blower System – The blower filter had to be changed regularly, and system had to be checked. Being that the blower motor is a mechanical device, the bearings will wear and the motor will fail over time.  These items should be checked quarterly as a PM which increase the cost to run the system.
   2. Super Air Knife – No moving parts to wear out. The only maintenance would be to change the filter once a year.
5. Versatility:
   1. Blower System – They did have a VFD to control the blowing force. But it was still very limited.  With a 36% increase in the bottle speed, they went beyond the maximum capacity of the blower.
   2. Super Air Knife – With a regulator and the shim set, the blowing force can be controlled easily from a breeze to a blast. With their application, the customer only required 40 psig with a standard 0.002” shim to clean and dry the bottles.  They had the option to adjust the regulator or change the shim to get the appropriate amount of blowing force.  So, with any changes in the bottling operations, the Super Air Knife could easily be adjusted.  Also, with the blowing force being optimal from a distance of 3” to 12” from the target, they had more flexibility in angle and distance to hit the moving target.
6. Quiet:
   1. Blower System – With the blower and turbulent air flow, the units are very loud. It had a sound level near 93 dBA, and with the operators working around the system, they needed PPE to protect them from the high potential of noise induced hearing loss.
   2. Super Air Knife – These units are very quiet. At 40 PSIG, the sound level is only at 61 dBA.  (Even operating at a pressure of 100 PSIG, the sound level is only 72 dBA).  This was very nice for the operators to work around as it wasn’t a constant noise nuisance.

In using the compressed air, the Super Air Knives are engineered to be very efficient.  The design creates a 40:1 amplification ratio which means that for every 1 part of compressed air, 40 parts of the ambient air is entrained.  But, even with the use of compressed air, the customer still wanted to share the ease of installing, the effectiveness of blowing, and the improvements to their process.  With the 6 points noted above, the customer wished that they would have contacted EXAIR at the beginning.

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