Technological advantages of Through-Air Drying for soft,
high-bulk tissue
A. Watzl, Fleissner GmbH & Co., Egelsbach, Germany
During the Nice Tissue-World 2003 we noticed a keen interest in tissue
lines with TAD (Through-Air Drying) technology in many discussions we
had with tissue producers during the exhibition.
Advantages of the TAD technology
I’d like to list below the reasons tissue producers stand during
the show for the trend towards TAD tissue products. There are two main
aspects: high quality and lower production costs.
The product achieved by TAD technology is considerably softer, bulkier
and has a better absorbency than conventionally produced tissue. The absorbency
can be increased by more than 50% by applying the TAD technology.
TAD technology allows saving of more than 20% of fibers and yet achieve
the same sheet size and appearance, i.e. TAD products provide a higher
value per weight.
In addition, the market shows that TAD tissue products can be sold at
a higher price than conventional tissue.
Fig. 1 summarizes the differences between conventional and TAD tissue.
The productivity of TAD lines is higher than that of conventional ones
due to the possibility of reducing the number of plies in the finished
product.
The production costs considering in essential fiber costs, energy costs
and depreciation clearly reveal the advantages of TAD technology to save
fiber costs and produce a softer and bulkier sheet. With fiber costs being
the major factor of the total product costs, saving of fibers has a serious
effect upon the final product costs.
Fleissner Through-Air drying technology
Being an inventor of Through-Air Drying technology, Fleissner Company
has supplied more than 45.000 Through-Air drums up to 8000 mm wide and
4800 mm (16 ft) in diameter to customers all over the world from the textile,
nonwovens, man-made fibers and paper industries in the past 70 years.
The High-Tech Through-Air Drum developed in 1988 has been supplied together
with Voith Sulzer for many lines for air permeable papers such as coffee
filters, tea bag papers, filters for vacuum cleaners, automobile filters,
etc. and also for the tissue sector with Beloit USA.
We explained the advantages of the Fleissner High-Tech drum to many interested
customers. The essential advantage of the bolted drum shell design over
the welded construction is the drum’s high stability and rigidity
for compensation of mechanical and thermal stresses.
Fleissner supplies High-Tech drums as single TAD tissue machines (see
fig. 2) with Yankee dryer or as dual TAD tissue machines (see fig. 3)
with Yankee dryer or as dual TAD tissue machines without Yankee dryer
in accordance with the TAD dryer arrangements.
The drums are designed as vacuum drums with air flow from outside to
inside of the drum (patent No. 558066 from 1932) or as pressurized drums
with airflow from inside to the outside of the drum (for the latter design
Fleissner also had a patent in 1966 – P 1635343.8 (V32107)).
Fleissner is prepared to send further information to tissue producers
that did not visit the Tissue-World show. |
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