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46<br />
Fig. 1: StratoSize.<br />
Fig. 2: StratoCoat.<br />
1 2<br />
section of the paper machine the paper<br />
maker is demanding longer run cycles<br />
with predictable roll changing intervals to<br />
eliminate unscheduled down time and reduce<br />
the costs associated with roll<br />
changes.<br />
Based on <strong>Voith</strong> <strong>Paper</strong>’s already proven<br />
rubber cover product line our, Research<br />
and Development Department began an<br />
extensive program to produce a new series<br />
of products which improves the wear<br />
properties of the cover while maintaining<br />
the excellent paper quality attributed to<br />
the roll cover. Our search was not only<br />
for a new and improved cover compound,<br />
but for a testing method that would accurately<br />
predict the abrasion resistance of<br />
the cover in the paper machine. The result<br />
of our research and development was<br />
an abrasion testing method that more<br />
closely simulates machine conditions and<br />
a new series of covers called Strato:<br />
StratoPress S and SR for demanding<br />
suction press applications<br />
StratoPress for demanding soft press<br />
applications (plain or blind drilled)<br />
<strong>17</strong>/04<br />
StratoSize for puddle size press and film<br />
press applications<br />
StratoCoat for film and blade coating<br />
applications.<br />
The new abrasion testing method is part<br />
of our entire testing process called<br />
Process Simulation Testing which incorporates<br />
testing methods that simulate<br />
operating conditions and provide excellent<br />
correlation between lab results and<br />
cover behavior in a paper machine. Traditional<br />
abrasion testing methods are done<br />
at room temperature under dry conditions<br />
which do not provide an accurate<br />
correlation between lab results and actual<br />
cover wear in the machine. Our new abrasion<br />
testing is done under conditions<br />
similar to actual operating conditions in<br />
order to accurately predict results seen in<br />
operation.<br />
The Strato Series of covers provides extended<br />
run cycles while maintaining the<br />
excellent surface qualities of our existing<br />
rubber covers. Using the results of our<br />
abrasion testing, we were able to predict<br />
run cycles 30% longer than the previous<br />
longest running covers. These lab results<br />
were confirmed by several field results of<br />
Strato covers.<br />
As noted previously, abrasion resistance<br />
is important for the performance of press<br />
roll covers. Improved abrasion resistance<br />
results in covers that not only maintain<br />
their crown profile for longer but also, in<br />
the case of drilled covers, have minimal<br />
hole cupping. This can result in longer<br />
times between grinds and improved press<br />
performance.<br />
The improved performance of the Strato<br />
series over competitors’ offerings has<br />
been demonstrated on a highly loaded<br />
jumbo press on a linerboard machine in<br />
the Southern US. A large diameter, blind<br />
drilled StratoPress cover was installed in<br />
the first press mating against a “super<br />
premium, super abrasion resistant” cover<br />
from a competitor. Although the covers<br />
had the same geometry there was completely<br />
unequal performance. When the<br />
covers were removed for grinding after a
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