Paper Technology International 2020 - Journal - Page 50

PAPERTECHNOLOGYINTERNATIONAL
Transferbelts no longer a niche product
Jochen Pirig, Strategic Product Manager Belting, Heimbach GmbH
INTRODUCTION:
More than two decades ago, an entirely new technology was introduced to the paper industry, and a whole new range of
possibilities was opened up: For the first time, the paper web could be transferred from the press into the dryer section in a
continuous closed draw. Heimbach was the first supplier to bring a complete polyurethane-coated transferbelt to the market.
In the meantime, the Webmover family has grown significantly and now offers solutions for almost every paper grade.
Forming fabrics, press felts and shoe press belts are directly
involved in the removal of water from the stock suspension and the
paper or board that is formed from it. Dryer fabrics, in turn, help
transfer heat from the drying cylinders to the paper web. They then
guide the web through the dryer section and onto the reel.
Common to all these fabrics are pre-determined paths for
the water or steam to be removed. In the case of forming/dryer
fabrics and press felts, this is done via the material itself, while in the
case of shoe press belts drainage channels in the form of grooves
do the work. Since smooth surfaces do not reate any storage
volume, they are now rarely encountered.
Central control function
As the name implies, a transferbelt conveys the paper web,
via closed draws, from the press section into the dryer section.
The belt is impermeable to water and as such makes no active
contribution to dewatering. Due to its specialised surface properties
the still damp and relatively unstable sheet structure is, as a first
step, directed to the outside of the transfer belt on leaving the press
section.
Because there is sufficient adhesion, the sheet is
transported along. No wrinkling, no edge curl. The next step is the
dryer section, where vacuum loaded rolls remover the web from the
transferbelt in a closed draw.
In short: to ensure trouble-free operation of a press section
with transfer belt, two criteria are of the utmost importance. Firstly,
the web must adhere sufficiently to the belt surface, yet still be easy
to release. Secondly, it is essential that these “tack and release”
properties are consistently maintained during economic downtimes.
A milestone for the industry
In 2006, Heimbach became the first supplier worldwide to
offer a unique product: Webmover, a complete polyurethane coated
transferbelt. One of the developer’s main declared goals was to
allow production speeds to be increased, and at the same time to
increase the service life of the closed draw transporter. While at the
time this applied to modern newsprint and other graphic paper press
technology, today the established machinery builders appreciate the
many advantages of transferbelts for other grades too.
New designs for new requirements
Something is happening. Tissue
manufacturers are now using transferbelts in
order to integrate free-standing shoe presses to
gain higher dry content. Producers of speciality
and lightweight packaging papers are also turning
to transferbelt positions in the search for greater
productivity. So it is only natural that Heimbach has
moved to tailor the proven features and benefits of
Webmover to cover these areas of application.
Today, the product range goes way beyond
the standard. The Webmover.HD variant (for Heavy
Duty) is used on positions that are subject to high
mechanical loads. With Webmover.Nonstick, belt
surfaces can be conditioned much more effectively,
and Webmover.T is the go-to design for tissue
applications.
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