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

Vacuum Generator System Selection – EXAIR E-Vacs

E-Vac Vacuum Generators are a highly efficient, versatile compressed air vacuum pump. Their versatility allows them to be adapted to many applications such as pick and place, clamping or vacuum forming. They’ve also been used in more unique applications like wood veneer pressing and basketball deflation.

EXAIR manufactures (3) types of E-Vacs – Low vacuum generators for porous materials, like cardboard, generating up to 21″ Hg with vacuum flows as high as 18.5 SCFM. Our high vacuum generators, designed for use with non-porous materials like glass or steel sheets, produce vacuum levels up to 27″ Hg and up to 15.8 SCFM of vacuum flow. The adjustable generators provide flexible vacuum performance, up to 25″ Hg and 81 SCFM,  which can be easily adapted to meet the application.

EXAIR E-Vacs provide instantaneous vacuum response, and are engineered for high efficiency to minimize air consumption.

 

When making a selection, there are a few key areas you want to consider:

Is the material porous or non-porous?

  • This will allow you to select the proper type of vacuum generator to fit the application and the type of vacuum cup best suited for the process.

 

What is the weight of the part and how will it be lifted?

  • If the part is being lifted where the vacuum cups will be positioned horizontally, like on top of a sheet of glass, you want to use a safety factor of 2 times the actual weight of the part. In processes requiring the cups be positioned vertically on the part, such as picking up a sheet of plywood and hanging it on an overhead conveyor, a safety factor of 4 would be used.

 

How many Vacuum Cups do I need?

  • Consider the quantity and placement to evenly distribute the weight for safely moving the material.
  • Depending on the maximum vacuum the generator produce, how much weight can each cup lift?
  • Make the cup selection per the following chart

 

Once you have selected the type and number of cups needed, you can then begin to look at which additional accessories items you might need.

  • Filters – supplying clean, dry air is key for maintaining optimal performance. An automatic drain filter  can be used to remove any water or contaminants in the supply line. If there is oil present, consider using an Oil Removal Filter.
  • Mufflers – help to reduce the noise level without restricting the airflow. We offer 2 different styles – Standard and Straight Through. Standards mufflers are a good choice where the supply air is clean and dry. These mufflers can only be used with the porous and non-porous generators. The Straight Through mufflers reduces sound levels by up to 26 dBA and are the better choice in processes where dirt or particulate may be present.
  • Tubing and Fittings – polyurethane tubing is available in 10′ sections up to 50′ for processes requiring the vacuum cups be placed in a location that wouldn’t allow for direct mounting to the NPT vacuum port on the generator or where multiple cups are needed. You want to keep the length of tubing as short as possible though for effective pickup and release time.
  • Check Valve – will maintain vacuum on the load if the supply pressure were to drop or be lost during operation.

For additional assistance selecting the proper E-Vac and accessories for your process, please contact an application engineer at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

Ion Bars Eliminate Jam In Fiberglass Production

Last week I worked with a specialty glass manufacturer who was experiencing a static issue in their fiberglass mat production. Their particular production cycle consists of a rotary spinning process where molten glass exits a furnace and goes into a cylinder with several holes that rotates at high speed, causing the glass to be “pushed” through the holes. Upon exiting the cylinder, the fibers are blown down on to a conveyor belt underneath, treated with a binder and pressed together, then sent to an oven to cure. After the sheets exit the oven, they are air cooled, cut to the desired length, then sent to a sorter that directs the material to collection bins, based on thickness and length. It is at this point that they were seeing the parts start to “bunch” up, which caused the system to be shut down so an operator could manually clear the jam and sort the mats. The customer has experienced static issues before in other parts of their plant and took some readings and were seeing a 4 kV charge on the surface of the mats.

After discussing the details of the application, I recommended they use our 24″ Ionizing Bar, the width of their widest mat. The Ionizing Bars produce a high concentration of positive and negative ions to eliminate the surface static of an object when mounted within 2″ of the surface of the material. At 2″ away, the units are capable of dissipating a 5kV charge in less than half a second. By placing a unit above and below the exit point of the sorter, they would effectively remove the surface charge and eliminate the potential jam.

Ionizing Bars Work
Ionizing Bars are effective up to 2″ away and require no compressed air to operate.

Our Ionizing Bars are available in lengths from 3″ up to 108″ for a variety of small or wide surface treatment applications. For assistance selecting the best product for your specific requirements, please contact one of our application engineers at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

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