Paper Technology Journal 19 - Voith
Paper Technology Journal 19 - Voith
Paper Technology Journal 19 - Voith
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2<br />
Approach flow system<br />
Thai Kraft PM 4<br />
From stock<br />
storage chest<br />
To broke chest<br />
PS12<br />
PS36<br />
PS36<br />
PS36<br />
PS36<br />
PS24<br />
Headbox<br />
same time reduce production costs, Thai<br />
Kraft initiated an optimization programme<br />
for the approach flow systems in Wangsala.<br />
This involved upgrading all the competitor<br />
pressure screens in the approach<br />
flow systems of PM 4, 5, 6 and 7 to <strong>Voith</strong><br />
C-bar technology.<br />
Up till then the screens all operated with<br />
rotors with four continuous foils each,<br />
together with milled baskets. Despite<br />
large slot widths of 0.45 mm, the mill<br />
could only achieve the required throughputs<br />
by running the screens with very<br />
Approach flow system<br />
Thai Kraft PM 5<br />
From stock<br />
storage chest<br />
Topliner<br />
Filler<br />
Backliner<br />
PS12<br />
To broke<br />
chest<br />
PS30<br />
PS30<br />
PS30<br />
PS30<br />
PS36<br />
PS12<br />
3<br />
Headbox<br />
PS30<br />
Headbox<br />
Fig. 1: Thai Kraft <strong>Paper</strong> Industry, Wangsala.<br />
Fig. 2: Layout of the stock approach flow<br />
systems for PM 4, 5, 6 and 7.<br />
Fig. 3: Screen upgrade package for the backliner<br />
of PM 6, consisting of C-bar basket, MultiFoil<br />
rotor and belt pulley.<br />
Approach flow system<br />
Thai Kraft PM 6 and 7<br />
<strong>Paper</strong> grade: CA 112 g/m 2 , EK 95 g/m 2 <strong>Paper</strong> grade: KL 125/150/185/230 <strong>Paper</strong> grade: KA 150/230<br />
From stock<br />
storage chest<br />
From stock<br />
storage chest<br />
Headbox<br />
high rotor speeds which meant a high<br />
specific energy consumption.<br />
This resulted in disturbing pulsations,<br />
while screening efficiency was not sufficient<br />
for the high paper qualities demanded<br />
by the market. In addition, the<br />
rotors and screen baskets exhibited very<br />
heavy wear.<br />
Fig. 2 shows the approach flow layouts<br />
of PM 4, 5, 6 and 7 together with the<br />
paper grades produced. PM 6 and 7 are<br />
identical.<br />
From stock<br />
storage chest<br />
Topliner<br />
Filler<br />
To broke<br />
chest<br />
From stock<br />
storage<br />
chest<br />
From stock<br />
storage chest<br />
Backliner<br />
PS12<br />
To broke<br />
chest<br />
PS30<br />
PS30<br />
PS36<br />
PS36<br />
PS30<br />
PS30<br />
PS12<br />
Energy savings using C-bar<br />
technology<br />
Headbox<br />
Headbox<br />
PS12<br />
Headbox<br />
7<br />
Trial delivery for PM 6<br />
backliner<br />
The optimization phase began in February<br />
2002 with a trial delivery of two optimization<br />
packages for the screens in the<br />
backliner system of PM 6 approach flow<br />
(Fig. 3).These were upgraded to <strong>Voith</strong><br />
MultiFoil rotors and 0.30 mm C-bar slotted<br />
baskets. At the same time the rotor<br />
speed was reduced by 29 %. Motor load<br />
dropped immediately by 47 % from 75 to<br />
<strong>19</strong>/05
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