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.
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