Making tissue means enclosing as much air with as
little fibre as possible. Bulk and caliper are fundamental quality
features, as they result in absorbency for towel or in structural
and surface softness for toilet, which are the main tissue products
in terms of worldwide consumption. Those important tissue quality
features are divided into three quality categories according to
the global requirements of different markets: standard, intermediate
and premium.
The Voith Paper ATMOS technology is the only technology
available in the market flexible enough to swing between those
three tissue quality categories allowing the tissue producers
to adapt to the different regional market requirements.
Standard tissue: Standard tissue quality is produced
on dry crepe tissue machines. This technology has been available
in the market for many decades, normally as crescent formers or
Duoformer machines with 1-2 presses, as well as shoe presses against
the yankee cylinder and a standard reeling system.
The ATMOS machine can easily swing to produce standard
tissue quality by replacing the structured fabric by a conventional
felt and by passing the ATMOS module within a few hours.
Intermediate tissue: Historically, 'intermediate'
tissue qualities have rarely been found, as only few technologies
can narrow the quality gap between standard dry crepe and structured
premium TAD or ATMOS. The technology known to produce the intermediate
quality category is the single recrepe (SRC). In recent years,
technologies have been developed to produce intermediate tissue
quality based on the principle of wet creping/negative draw, but
some major issues such as operational complexity, fabric lifetime
and overall process efficiency are the bottleneck of such technologies.
The most feasible alternative to produce intermediate
tissue quality is to operate an ATMOS machine with fine mesh structured
fabrics to increase the intimacy between the fabrics in the ATMOS
module resulting in dewatering to dryness levels typical for standard
dry crepe machines (above 40%). The result is structured tissue
production with intermediate quality between standard dry crepe
and premium and, overall energy consumption near or even lower
than the level achievable with standard dry crepe technology.
Structured premium tissue: The premium quality is
the best tissue quality available in the market and is produced
on through air drying (TAD) and ATMOS machines.
Since 2006 premium tissue has also been produced
with ATMOS technology and since the end of 2007 has been freely
available in the market. With this concept, quality is generated
during the tissue sheet formation using a crescent former configuration
of a conventional outer forming wire and inner structured fabric.
The tissue is mechanically dewatered to 36-38% solids by combined
high vacuum and temperature as well as low pressure field application
in the ATMOS module. The sheet is carried by the structured fabric
from the headbox to the yankee, avoiding tensile losses of fabric-to-fabric
transfer. As with TAD technology, only a minor part of the sheet
surface area is pressed during the yankee transfer, so 75% of
the sheet remains protected in the structure of the fabric.
Commercially, the ATMOS technology proved to be
operationally simple and robust, allowing a high level of flexibility
for grade changes over the complete range from structured premium
to standard tissue operating efficiently on virgin fiber as well
as on 100% recycled fiber. Besides, the high solids allow up to
50-55% lower energy consumption values than TAD machines when
producing premium tissue. Summarizing the benefits of the ATMOS
technology's ability to swing between the different tissue quality
categories:
ATMOS for standard
tissue
- Easy swing from ATMOS
to standard tissue
by replacing the structured fabric by a felt
ATMOS for intermediate tissue
- Easy swing from premium
to intermediate
by changing the molding fabric design
- Suitable for toilet and towel paper production
- Up to 50% higher quality than dry crepe
- Up to 15-20% lower energy consumption per case than
dry crepe
ATMOS
for structured
premium tissue
- Same premium
or even better
quality than
TAD with 100% virgin
or recycled fibres
- Up to 50-55% energy saving versus TAD
- Up to 30% fibre savings versus dry crepe
The combination of being able to save energy and
fibre as well as run with 100% recycled fibre plus the ability
to easily swing between the three different tissue quality categories
make ATMOS an environmentally friendly technology and thus the
most feasible and sustainable alternative for the tissue producers
to operate an optimum quality/cost ratio in their market region
attending any regional market requirement.
