Paper Technology International 2024 - Journal - Page 29

PAPERTECHNOLOGYINTERNATIONAL
Figure 4: Hydrofoil for usage in paper machine forming section
CeramX material get used in forming sections up to 1200
m/min and as uhle box cover in press sections up to 2000 m/min,
it cost just ~ 10 % of elements in aluminium oxide ceramic, other
ceramic grades are even more expensive. When changing the
design of existing dewatering elements it is always usefull to try the
new design 昀椀rst in CeramX material before investing in new ceramic
parts. Also as spare part for drainage elements in brittle ceramic the
CeramX material is predestinated as the 昀椀xed capital in the storage
get reduced by 90 % and can get used for other projects.
Many production manager and process engineers report that
old ceramic elements have sometimes round front tips which create
a remoistening instead of drainage and worn foils without foil angele
can’t create microturbulences but when there is no budget for new
ceramic or a ceramic grinding, the production is forced to produce
with existing elements. CeramX foils are the perfect solution as the
wear resistant material keeps longer the foil angle on the surface
and a frequent change of the dewatering elements gives always a
fresh front tip and foil angle on the surface which is important for
even dewatering and good sheet formation.
The better sheet formation results in:
- better and even dewatering about the complete machine
width
- higher paper strength what could reduce starch
consumption
- less needed vacuum what reduces 昀椀ber loss and increase
paper volume as well as stiffness
- lower energy consumption for dewatering what saves cost
Suction roll sealing strips in 昀氀exible rubber graphite for easy
handling and lowest friction.
An essential and very critical position in paper and board
machines are the sucton rolls, they are important for dewatering,
direction changes of the sheet or for picking the sheet from wire
section to press section. In most paper machines it is impossible to
transfer the paper sheet into press section without a stable vacuum
on the pick up roll. To guarantee this stable vacuum Wefapress has
developed suction roll sealing strips in FlexGuard, which is a rubber
graphite material. The high graphite content ensures excellent
sliding properties and self lubrication in case of a water lubrication
fail, while the rubber content keeps the sealings 昀氀exible and assures
easy handling.
Figure 6: FlexGuard suction roll sealing strip.
The material adjust itself very good to the roll shell pro昀椀le
and ensures a quick function directly after installation. Like this it is
possible to work with very low air loading tube pressure of 0,3 Bar or
less. The low pressure allows for the lubrication water to get on top
of the sealing strip and to seal the gap in between sealing and roll
shell. By this, the water seals the vacuum without any wear of the
sealing stip. In addition the low pressure and friction ensures also
reduced drive power consumption, as well as increased sealing strip
life time.
Figure 5: FlexGuard end sealing.
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