More Force is not Always Better for Cleaning Glass

Glass Annealing Machine with model 110230

A float glass company purchased an EXAIR model 110230 Super Air Knife kit to clean the surface of glass sheets.  The production manager watched the video of the performance of the Super Air Knife, and he was amazed at the efficiency, effectiveness, and safety that they could provide.  (We have many EXAIR Product videos here).  After they received the Super Air Knife, they mounted it after the annealing process to remove any specks of dirt and debris prior to the final visual inspection.  They were getting some false rejections from contamination that remained on the sheets, and they believed that they needed more force to better clean the surface of the glass.

The blowing system was operating at 73 PSIG (5 bar) air pressure, the maximum amount that could be supplied at the machine.  With the dynamics of the Super Air Knife, the blowing force could be increased by changing the shim thickness.  The plant manager contacted me about the characteristics in force and flow by changing from the standard 0.002” (0.05mm) thick shim to the 0.003” (0.08mm) or 0.004” (0.1mm) thick shim.  (These shims are Included in the shim set for aluminum Super Air Knife kits along with a 0.001” (0.025mm) thick shim).  As an Application Engineer at EXAIR, I was inquisitive about the application and wanted to do a “forensic” analysis of the system to generate the best suggestion.  So, I had him send me pictures of their setup.

With non-conductive materials like glass and plastic, static can be a huge issue.  Static forces can easily be generated and will cause dirt and debris to “stick” to a surface.  This attraction is very strong and will make it very difficult to remove.  If the static force can be neutralized, then the contamination can easily be removed from a non-conductive surface.

With this understanding, my initial suggestion for the company above was to remove the static charges from the surface of the glass with an EXAIR Static Eliminator.  With the complimentary design of the Super Air Knife, it is simple to mount an Ionizing Bar directly to the Super Air Knife that they currently installed.  I recommended a model 8030, 30” (762mm) long Gen4 Ionizing Bar, and a model 7960 Power Supply to transform the Super Air Knife into a Gen4 Super Ion Air Knife.  The positive and negative ions that are generated by the Gen4 Ionizing Bar can be carried by the laminar air flow of the Super Air Knife to treat the surface.  This combination can work well to remove static charges up to 20 feet (6m) away.  Once the static is removed, the force of the air stream would easily remove any dust or debris from the glass surface.

Gen4 Super Ion Air Knife

As an added note from the picture above, I recommended a different position for the Super Air Knife, or soon to be Gen4 Super Ion Air Knife to optimize the blowing area.  The glass company had the air knife positioned to blow straight across the surface of the glass.  For proper cleaning and better contact time, I suggested to mount the Super Air Knife with the Ionizing Bar about 6” (152mm) above the surface of the glass and angle it to about 45 degrees.  This would increase the contact angle and allow for a better blowing force to remove all the debris.  By adding the Gen4 Ionizing Bar and adjusting the blowing angle, they were able to reduce the air pressure from 73 PISG (5 bar) to 30 PSIG (2 bar); saving compressed air and reducing false rejections.

Pictures are always helpful in analyzing an application.  With the company above, we were able to optimize their cleaning process and reduce the total amount of compressed air required.  If you find that you need more force to clean a non-conductive surface, EXAIR Static Eliminators will resolve these static problems.  If you would like to discuss your application with an Application Engineer at EXAIR, we can go through the “forensics” analysis for optimization.

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

Long EXAIR Super Air Knife Kit Provides Upgrade to Existing Blow-off Application

One of our long standing customers is a float glass manufacturer in the Middle East region. They had long been a customer for our Cabinet Cooler systems as their processes obviously tend to be quite hot.

They had recently come to me with a new problem they had in their pattern line wire separator. There are two sets of clamps that grip the glass, one set upstream and another downstream. The problem was that small chips were accumulating on the clamping pads and causing visual defects in the glass when clamped upon.

Their previous blowing “system” if you want to call it that, was a simple, perforated pipe connected to compressed air. The pipe was ineffective from many points of view. It did not produce a very forceful stream of air to blow the chips, it consumed a ton of compressed air when it was in operation, was very loud and quite un-safe to the operators in the area.

The one thing that the customer needed was a length of 84 inches for their blow off solution. EXAIR was able to meet this need fairly easily with our 84” Aluminum Super Air Knife Kit which was available from stock.

LSAN

The Super Air Knife was positioned along-side the glass line to provide a momentary blast of air all along the length prior to gripping with the upstream and downstream gripping pads. This action cleared any debris and stopped the glass from being defective as a result of the clamping action.

The key to success in the application was in being able to provide a forceful blowing action evenly all the way along the length of the glass so no spots were missed.

Do you have a large or wide area blow-off application that you would like to discuss? Please contact our Application Engineering department and we will be glad to discuss your application. Or you can fill out our Application Assistance Worksheet and send it in for us to review and follow up with you.

Neal Raker, Application Engineer
nealraker@exair.com