Paper Technology Journal 17 - Voith

42
Robert Hotter
Finishing, Tail Threading Group
robert.hotter@voith.com
Christophe
Le Morzadec
Finishing, Tail Threading Group
christophe.lemorzadec@voith.com
Fig. 1: Before and after chart for production
capacity, speed and grades at Condat line 89.
Wire Width
Paper Width
Paper Weights
Design Speed
Capacity
17/04
Before
5,768 m
5,245 m
90-135 g/m2 1,000 m/min
566 tons/24 h
Excellent threading performance
achieved at Condat
Condat, a member of the Lecta Group since 1998 together with
Garda in Italy and Torras Paper in Spain, is a manufacturer of woodfree
coated papers. In autumn 2001 Condat decided to carry out an important
re-build of line 89 within the scope of the Lecta Group’s investment program.
After
5,768 m
5,245 m
90-135 g/m2 1,200 m/min
592 tons/24 h
Before the work began, the customer
stated clearly the most important goals
for this major optimization plan. The target
of the first stage was to improve the
formation process and overall machine
productivity through reduction in both
the number and duration of breaks. A
major part of this included reducing
threading times and the clean-up times
after a break.
After 10 years of production Condat line
89 faced some specific problems; an inefficient
forming section, a large number
of breaks in the dryer section, long cleanup
times and an unreliable and slow
threading process. The threading was difficult
mostly due to the on-line coaters
on this paper machine. After completing
a comprehensive threading analysis for
Line 89, the following problems were
identified with the original threading
process: threading of coater 1 was difficult
and inconsistent; the tail ran out of
the ropes between the dryer sections;
threading performance varied with crews;
manual threading was compromising operator
safety and the clean-up times were
long after dirty thread-ups.
Voith received the order for the re-build
of line 8 in March 2002. The scope of
delivery included DuoShake, DuoFormer D
and JetFlow F components along with
three VTT conveyor sections, complete
erection, personnel training and start-up
supervision.
The DuoShake installed on Condat’s PM 6
had already proven its efficiency. Duo-
Shake contributes to the quality of formation
by allowing the MD/CD ratio to be reduced.
It also ensures that no disturbing
vibrations are produced. The DuoFormer
D is a hybrid former with optimum position
on the wire and an efficient design of
the top wire suction box and counter
blades. The JetFlow F is a free jet coating
system that can be easily incorporated
into the coaters, taking the place of the
applicator roll. With JetFlow F the web no
longer has to pass through a nip which
reduces the risk of breaks. The design
and control of JetFlow F and the coating
color circulation system prevents contamination,
which significantly reduces
cleaning efforts after a break.
A TEAMS assessment (Threading Evaluation
And Managed Solutions) was conducted
by the Voith Tail Threading Group
(TTG) before the optimization to identify
threading problems. In the TEAMS assessment
phase, two Threading Process