BERG SEMINAR 13-15 February 2009

RUNNABILITY TECHNOLOGY FOR PAPER MACHINE

PRESS SECTION AND SINGLE FELTED DRYING SECTION

BERG SEMINAR 13-15 February 2009 Jouni Dahllund

BERG SEMINAR 13-15 February 2009

PRESS SECTION AND PRESS TRANSFER

BERG SEMINAR 13-15 February 2009

Problems at press section:

Poor machine/roll geometry too long opened and unsupported sheet draws

Moving surfaces such as felts, fabrics, rolls and the web considerable air flows and pressure differences sheet flutters

High draw breaks, defects, high schrinkage and quality problems

The sheet MD/CD strength ratio varies with an negative effect on runnability in printing.

BERG SEMINAR 13-15 February 2009

EVsp web stabilizer eliminates blowing problems in free-standing presses

Typical problem:Press felt pumps and produces air layer between the web and the press felt. Before the press nip occurs an air bubble causing breaks and defects. Elimination of this phenomenon to be done with excessive draw, uhle box or the web stabilizer.

EVsp eliminates the blowing problem by blowing air out from the press nip and by creating vacuum between the box and press felt vacuum by blowing no mechanical contact to felt (no wear or damages) sheet in contact with the press felt

EVsp does not replace the suction transfer roll, but completes its function. Speed < 800 m/min even without suction transfer roll!!

BERG SEMINAR 13-15 February 2009

EVp web stabilizer supports the sheet from the press to the dryer section

Creates a high vacuum between the box and the dryer fabric.

sheet in contact with the drying fabric less breaks low draw easy tail threading

Lower draw means also that there is less chemical pulp needed and that it is easier to achieve strength requirements.

BERG SEMINAR 13-15 February 2009

SINGLE FELTED SECTIONS

- In the beginning of the drying section, the first single felted groups are very sensitive to runThe web is still very wet and breaks easily

- Without support on web release between top cylinder and bottom roll the wet web tends to follow upper cylinderbreaks and paper defectshigh drawSolution vacuum behind the release

Air flows at web down- and uprun tend to release the web from the fabric breaks, creasing and paper wrinkles caused at upper cylinder nipSolution stabilizer (=vacuum) behind the fabric

PROBLEMS:

BERG SEMINAR 13-15 February 2009

After EVG modification

EVsf web stabilizers

EVp web stabilizer

grade: copy paper, 1000 m/min

References of EV press- and single felted section optimization

BERG SEMINAR 13-15 February 2009

grade: sack paper

EVsf web stabilizersEVsp web stabilizer

References of EV press- and single felted section optimization

BERG SEMINAR 13-15 February 2009

EVsf web stabilizers

EVp web stabilizer

EVsp web stabilizer

grade: cigarette and tipping paper, speed 600 m/min

References of EV press- and single felted section optimization

BERG SEMINAR 13-15 February 2009

For superior runnability and ropeless tail threading

at single felted section

BERG SEMINAR 13-15 February 2009

For superior runnability and ropeless tail threading at single felted section

In EV EasyGo concept EVsf2-V Web Stabilizers are installed on top of the drilled vacuum rolls to support the sheet (stabilizer) and create a vacuum inside of the vacuum roll (suction). This box has two air connections i.e. blow and suction.

Drilling of the cylinders on site without cylinder remove enables minimal downtime.

BERG SEMINAR 13-15 February 2009

Excellent runnability of the drying section

Ropeless tail threading

Additional PM speed

Fewer breaks and less time required for tail threading: Additional production time

Improved paper quality

Drilled holes of the vacuum rolls are big enough to prevent clogging (Ø6…8 mm)

Cost-effective investment, short pay-back time

No fabric contact

Drilling of the cylinders easier and less expensive than exhausting from the cylinder heads: no grooving and change of cylinder heads and bearings mean also

minimized down time

BERG SEMINAR 13-15 February 2009

Burgo Villorba, PM 8 in Italy - LWC, speed 1500 m/min, width 4,5 m

After EV Drying section optimization

3 x EVsf2-V web stabilizers

15 x EVdf web stabilizers

EV Cleaner

References of EV EasyGo concept

BERG SEMINAR 13-15 February 2009

References of EV EasyGo concept

Cartiere Miliani Fabriano, PM 3, Italy, copy paper, speed 1100 m/min, width 4,5 m

After EV Drying section optimization

EVdf web stabilizers EVsf2-V web stabilizers

Ropeless tail feeding with TailBlades

EVdf web stabilizers

NEW TECHNOLOGY

FOR THE FIRST DRYING SECTION GROUPS TO OPTIMIZE WEB

RELEASE BETWEEN UPPER CYLINDER AND VACUUM ROLL

BERG SEMINAR 13-15 February 2009

technology with EVsf3-V Web Stabilizer:

- High release vacuum zone

- Ensures optimal sheet release from upper cylinder

- Eliminates sheet flutter and paper defects

BERG SEMINAR 13-15 February 2009

High release vacuum

Normal vacuum

Normal vacuum

BERG SEMINAR 13-15 February 2009

0.5 0.750000000000003

1 1.50

200

400

600

800

1000

1200

1400

1600

1800

2000

4 mm distance nozzle/fabric 5 mm distance 6 mm distance 8 mm distance

VACUUM WITH DIFFERENT AIR PRESSURE

VA

CU

UM

AT

HIG

H P

RE

SS

UR

E A

RE

A [

Pa]

PRESSURE AT NOZZLE [bar]

Nozzle distance to fabric 4-8 mm

BERG SEMINAR 13-15 February 2009

THANK YOU!