FIELD OF APPLICATION
The present invention relates generally to an online roll cleaning device for
preventing roll dent defect in cold rolled strip. In particular it relates to cleaning
of top and bottom rolls of a burr masher unit to prevent dents along the length
of the rolled strip due to entrapment of strip-borne particles and metallic fines.
It also relates to cleaning of tension leveller de-curve rolls for correction of shape
of cold rolled strips.
BACKGROUND OF THE INVENTION
A burr masher unit is used for removing burr from the edge of the strip after
trimming. The problem is of dent from the top and bottom rolls of the burr
masher unit due to entrapment of strip-borne particles and metallic fines
resulting in breakdown loss like frequent line stoppage for roll cleaning and poor
quality with dents along the length of the strip.

At the recoiling and inspection lines in cold rolling mills there can be frequent
production stoppage of cold rolled material due to the problem of dent appearing
from de-curve roll of the tension leveller unit for correcting the shape of input
strip due to entrapment of strip borne particles and metallic fines. This results in
breakdown loss like frequent line stoppages for roll cleaning and poor quality of
strips with dents.
The frequency and intensity of the dents are in proportion to the processing
speed and age of previous processing lines like skin pass mill (SPM), batch
annealing furnace (BAF), electrolytic cleaning line (ECL) and pickling tandem cold
rolling mill (PLTCM).
In order to overcome the problem use of custom made doctoring system was
considered to fit the application at recoiling and inspection lines. However, for
installing this a lead-time of a minimum of one month would be required. This
would mean stoppage of the cold rolling mill. The cost of such a system is also
prohibitively high. Further no manufacturer of doctor blades will be prepared to
give any guarantee for 100 % eradication of dents in the strips.

There was therefore, a need for providing a cleaning system for the trimmer burr
masher unit and for the tension leveller unit to eliminate formation of dents due
to entrapment of strip-borne particles and metallic fines.
SUMMARY OF THE INVENTION
The main object of the present invention therefore is to provide an online roll
cleaning device for the rotating rolls for continuous cleaning to produce dent free
strips.
This and other objects of the present invention are achieved by providing a
cleaning device with a wiper pad and an abrasive structured strip covered by a
specially designed Lint Free cloth.
For continuous cleaning of rotating rolls, the cleaning device can be pressed onto
the rolls using a suitable arrangement. Such an effective cleaning mechanism at
the tension leveller unit and the burr masher unit is capable of solving over 90 %
of the dent problem in the strips.

For cleaning de-curved rolls a pivoted lever and a counter weight arrangement
can be used for keeping the device pressed onto the rolls.
In a burr masher until the top and bottom burr masher rolls are each provided
with one roll cleaning device pressed onto the burr masher rolls.
In a preferred embodiment the present invention provides an online roll cleaning
device for preventing roll dent defect in cold rolled strip, characterized by a
metallic frame carrying the device, said device comprising a wiper pad for
applying pressure to maximize the area of contact between the cleaning device
and the roll; an abrasive structured strip for giving necessary softness and
scrubbing action of particles from the roll surface; and a special cloth covering
for said wiper pad and said abrasive structured strip for wiping out metallic fines
and non-metallic particles from the roll surface without creating any scratch mark
thereon.

BREIF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention can now be described in detail with the help of the figures of the
accompanying drawings in which
Figure 1 schematically shows conventional doctor blade
system used for line roll cleaning.
Figure 2 shows the line overview of the recoiling and
inspection line where the present invention is applied.
Figure 3A shows the cleaning device installed in a tension leveller unit.
Figure 3B shows a wiper pad used in the device.
Figure 3C shows an abrasive structured strip like 3M Scotch Brite.
Figure 3D shows the special cloth covering used in the device.

Figure 4 shows the cleaning device installed on the top
and bottom rolls of a burr masher unit.
Figure 5 shows a zoom-in view of the tension leveller de-curve roll
with the online cleaning device of the present invention.
Figure 6 shows the online roll cleaning system of the present
invention fitted in the recoiling and inspection line.
Figure 7 shows the intensity of the dent problem before and
after fitting the cleaning device of the present invention.
Figure 8 schematically shows the cleaning device of the
present invention in more details.

DETAILED DESCRIPTION OF THE INVENTION
The conventional doctor blade system of cleaning line rolls is shown in Figure 1.
Figure 1(a) shows double doctoring system with shower assembly. Figure 1 (b)
shows top press double doctor with shower. Figure 1 (c) shows top calendar
double doctor first doctoring second with mild abrasive blade for roll
conditioning. Figure 1 (d) shows center press equalizer double doctor with
shower.
The line overview of the recoiler line is shown in detail in Figure 2 with the
device of the present invention installed at points marked by arrow (A).
The roll cleaning device 1 of the present invention is shown in more detail in
Figure 8. Reference numeral 3 represents the de-curve roll of the tension
leveller (or rolls 3', 3" of the burr masher unit). The dent causing particles are
shown at 22, which can be wiped clean by a specially designed cloth 24. This

can be a LINT FREE cloth of 3M. The cleaning device is provided with an
abrasive structured strip 26 which can be of Scotch Brite material from 3M. The
Scotch Brite material provides a scrubbing action to the cleaning process. A
wiper pad 28 made of hard rubber is provided as a foundation for applying
pressure in order to maximize the area of contact between lint-free cloth
covering 24 and rotating rolls 3, 3', 3".
The cleaning device 1 installed in a tension leveller unit is shown schematically in
Figure 3A. As shown in the cleaning device 1, comprising the hard rubber wiper
pad 28 and the abrasive structured strip 26 made preferably from Scotch Brite
material of 3M, covered by the special Lint Free cloth covering 24 tied at the
back by lace and held in position by a metallic frame 4. The device 1 is kept
pressed to roll 3 by means of a lever 5 pivoted at position P and a counter
weight 6 connected to end of lever 8 with a chain 7.

The wiper pad 28 used for applying pressure onto the rolls for maximizing the
area of contact between Lint Free cloth 24 and the rotating rolls 3, 3', 3" is
shown is Figure 3B.
The wiper pad 28 is made from hard rubber and provided with a bottom support
for giving the necessary rigidity to the roll cleaning device 1.
Figure 3C shows the abrasive structured strip 26, which can be made from
Scotch Brite material made by 3M. The Scotch Brite material 26 gives the
necessary softness to the cleaning device and its abrasive quality provide proper
scrubbing action of particles from the surface of rolls 3, 3', 3".
The specially designed cloth covering 24 can be made from Lint Free cloth
supplied by 3M and shown in Figure 3D.

The Lint Free cloth covering 24 is provided with laces L which can be used for
tying up at the back of the covering.
The arrangement for installing the roll cleaning device 1 of the present invention
is schematically shown in Figure 4 in side view and front view. Two roll cleaning
devices 1 are each mounted on two blocks 8.
Figure 5 shows a zoom-in view of the tension line de-curve roll for the recoiling
and inspection line. The rotating roll 1 requires continuous cleaning to produce
dent free strip 2.
The online cleaning device 1 of the present invention is shown with Scotch Brite
and Lint Free cloth.

Figure 6 gives a photographic view of the roll cleaning system of the present
invention for the trimmer burr masher unit at the recoiling and inspection lines.
Roils which require continuous cleaning are shown at 3', 3". This ensures
production of dent-free strip 2. The online cleaning devices shown at 1 are
provided with specially designed Lint Free cloth, which can be replaced in about
15 minutes time.
As a result of the implementation of the roll cleaning device of the present
invention more than 90 % of the dent problem was solved. This is graphically
shown in Figure 7.
Although the invention has mainly been described in relation to recoiling and
inspection lines in rolling mills of a steel industry, it can be used in slitting and
cut-to-length lines, tension leveller units in galvanizing lines and blanking lines
and blanking lines in automobile industry.

It can also be used in non-ferrous industries like aluminum foil rolling mills and
also in paper and cloth mills.
The salient features of the roll-cleaning device of the present invention includes
gentle cleaning of the roll surface of a rotating roll without creating any scratch
marks thereon.
The construction of the device is very cost effective and provides a simple and
effective solution to the problem of roll cleaning when compared with custom
made known doctoring systems.
The cleaning device of the present application is suitable for rotating rolls having
a surface roughness less than or equal to 3 micron Ra. The device can
withstand a rotating speed of upto 500 RPM and can work on both dry and wet
surfaces. The device is easy to maintain with very little running cost on
maintenance.

WE CLAIM
1. An online roll cleaning device for preventing roll dent defect in cold rolled
strip, characterized by a metallic frame carrying the device, said device
comprising:
a wiper pad for applying pressure to maximize the area of contact
between the cleaning device and the roll;
an abrasive structured strip for giving necessary softness and
scrubbing action of particles from the roll surface; and
a special cloth covering for said wiper pad and said abrasive
structured strip for wiping out metallic fines and non-metallic
particles from the roll surface without creating any scratch mark
thereon.

2. The roll cleaning device as claimed in claim 1, wherein said wiper pad is
made of hard rubber, like 3 M wiper pad.
3. The roll cleaning device as claimed in claim 1, wherein said abrasive
structured strip is a 3 M make Scotch Brite Strip.
4. The roll cleaning device as claimed in claim 1, wherein said special cloth
covering is made of 3 M Lint Free cloth.
5. An online roll cleaning system for tension leveller de-curve roll comprising
a roll cleaning device as claimed in claims 1 to 4, wherein said device is
pressed on to the de-curved roll with the help of a pivoted lever and a
counter weight arrangement.

6. An online roll cleaning system for a burr masher unit with a top and a
bottom roll comprising a pair of roll cleaning devices as claimed in claims
1 to 4, wherein the top burr masher roll and the bottom burr masher roll
are each provided with one roll cleaning device pressed on to the
corresponding burr masher roll.
7. An online roll cleaning device for preventing roll dent defect in cold rolled
strip, substantially as herein described and illustrated in the
accompanying drawings.

The main object of the present invention therefore is to provide an online roll
cleaning device for the rotating rolls for continuous cleaning to produce dent free
strips. This and other objects of the present invention are achieved by providing a
cleaning device with a wiper pad and an abrasive structured strip covered by a
specially designed Lint Free cloth.
For continuous cleaning of rotating rolls, the cleaning device can be pressed onto
the rolls using a suitable arrangement. Such an effective cleaning mechanism at
the tension leveller unit and the burr masher unit is capable of solving over 90 %
of the dent problem in the strips.
For cleaning de-curved rolls a pivoted lever and a counter weight arrangement can be used for keeping the device pressed onto the rolls.
In a burr masher until the top and bottom burr masher rolls are each provided with one roll cleaning device pressed onto the burr masher rolls. In a preferred embodiment the present invention provides an online roll cleaning
device for preventing roll dent defect in cold rolled strip, characterized by a metallic frame carrying the device, said device comprising a wiper pad for applying pressure to maximize the area of contact between the cleaning device
and the roll; an abrasive structured strip for giving necessary softness and scrubbing action of particles from the roll surface; and a special cloth covering for said wiper pad and said abrasive structured strip for wiping out metallic fines and non-metallic particles from the roll surface without creating any scratch mark thereon.