Duane Lanham, General
Supervisor, WCI Steel, Inc., Warren, Ohio
"We rely on this
cleaning system to
help us produce prime silicon steels at WCI Steel."
our silicon annealing line, the strip surface has to be spotless when it
enters the annealing furnace. So, we checked out cleaning systems
supplied by half a dozen companies around the world. In the final
analysis, the answer was right here in our own backyard."
system removes iron fines, rolling oils, mill grime and other contaminants
from the strip surface. It does its job extremely well - coil after
coil -. Since the system effectively removes abrasive iron fines,
another benefit is longer roll life for our furnace hearth rolls.
You can't ask more of your equipment than to have it work hard for you and
THE PROOF IS AT YOUR FINGERTIPS!
White Glove Strip Cleaning System will stand up to the
relenting effects of moisture, chemical detergents, and elevated
temperatures. And of course, it will get the strip clean, dry, and
ready for the next operation.
corrosion-resistant tanks are made of stainless steel or polypropylene
and reinforced with steel framing. Our statically balanced,
fabricated rolls are covered with elastomer all the way to the
journals. Baffles and slingers on the roll necks keep solution
away from the bearings. Separate, sturdy, steel stanchions support
the rolls and their adjustable speed drives.
on proven technology,
engineers each system for its particular application. Ancillaries,
such as the fume exhaust system and off-line storage tanks, are totally
compatible with other components in the system. The typical system
shown here includes the following equipment:
High Pressure Spray Cleaner
strip enters the spray cleaner, where recycled detergent solution
removes rolling oils and loose particulate matter. The solution is
pumped through high impingement nozzles. Spray headers mounted
above and below the strip are easily removed for cleaning, repair, or
replacement while the line is operating. Optional self-cleaning
nozzles are available.
Entry and exit wringer
rolls serve as damming rolls to contain the solution within the tank and
to prevent dragout.
cleaning is highly effective in removing rolling oil. The choice
of medium or high current density cleaning depends upon the application.
Steel electrode grids are supported in a polypropylene tank, about
twenty-five feet long, with a wall thickness of at least one inch.
We connect automatic polarity reversing rectifiers to the grids with
heavy copper bus bars. Rectifier voltage varies, but it is in the
range of 18 to 45 volts D.C. Rectifier current, which can be as
high as 20,000 amps, is controlled automatically as a function of line
speed. The rectifiers can be either air- or water-cooled.
rolls and large diameter sink rolls guide the strip into and out of the
tank . Exit wringer rolls minimize carryover of the solution.
brushing effectively removes metal fines and annealing smut.
Motor-driven screw jacks automatically position the four brushes - two
below and two above the strip - to adjust for brush wear. Preset
watt loads on the motors determine the brush contact pressure.
Backup rolls support the strip at each brush: pneumatic cylinders
pivot them out of the way quickly for weld or stitch passage.
Spray headers before and after each brush wet the strip and flush loose
matter from the surfaces. The spray headers and the brushes are
designed for easy removal. Wringer rolls minimize carryover into
the rinse section. Pneumatic cylinders open the top wringer roll
for threading. (Some installations have a second brushing machine
in place of the electrolytic cleaner.)
Cascade rinsing conserves water and heat by spraying large
volumes of re-circulated water onto both surfaces of the strip in a sectioned tank. The
water that falls back into each section or stage is re-circulated to the spray headers.
Water overflows from one stage to the next, cascading counter to strip travel. Fresh
make-up water is introduced into the last stage, so the cleanest water is in the final
rinse stage. The more stages there are, the less make-up water that is needed.
builds cascade rinse tanks with two to five stages, depending upon
the application. Wringer rolls confine the dirtiest water to stage #1, and remove most of
the moisture before the strip enters the hot air dryer.
Hot Air Dryer
Before it exits the system, the strip must be absolutely dry to
prevent water staining or subsequent oxidation. This dryer has four upper and four lower
headers that blast hot air onto the strip. A manifold connects the headers to the blower.
Incoming air can be heated by gas (direct or indirect), steam, or electrical resistance.
The air stream is normally heated to at least 150° F above the ambient temperature. Sound
absorbing materials keep the noise level at less than 85 Dba within ten feet of the