Wet streaks

1. Check secondary slice and deflector setting.
— be sure perforated rolls are operating correctly.
— check breast roll discharge and rewetting at former.
2. Check for warped or ridged slice, or warped headbox throat.
— repair if needed.
3. Adjust slice to obtain uniform basis weight profile and a straight dry line.
4. If from ridged wire, check all rolls inside and outside for a stock build-up.
— check fit of doctors.
— clean off rolls and rub out ridge.
5. Correct misalignment of any forming table elements.
— check and clean any drainage elements that need it.
6. Have moisture tests taken across press.
— take a nip impression at felt change to ensure proper crown and uniform pressing.
— check and adjust refining if sheet is excessively wet into presses.
7. Change any unevenly worn press felts.
8. Leaking or spilling press pans should be repaired promptly.
9. Improve water removal to avoid rewetting from grooved press rolls.
10. Check groove geometry, purging shower angle, shower water pressure, and nozzle cleanliness.
11. Streaky dryer felts not allowing even extraction of moisture across machine should be cleaned or changed.
— check high pressure felt showers and clear any plugged nozzles.
— wash or replace dirty or filled wet end or dryer felts.
12. Ensure that dryer felts are not running slack.
— adjust through machine.
13. Poor ventilation in dryers indicated by sweating in dryer hood.
— ensure that hood exhaust fans are running and that Ross-Grewin system is on.
— check for arrangement of pocket ventilation, air currents, hood exhaust system, or improper air balances.
14. Dryer felts are not dry on return run as indicated by felts giving off moisture.
— slow machine down, then check temperature of felt dryers.
— check and clean vacuum boxes.
15. Check felt stretcher to be sure it is operating properly.
— may then increase tension on felt.
16. Streaks may be caused by irregularities in the slice discharge being set into sheet by excessive drainage or lack of turbulence right after the slice.
17. Check for damage in pressure screen baskets.
18. Check operation of size press for correct pond level, loading, and worn or dirty rolls.
19. Check operation of calender, especially for worn or dirty rolls.
20. Check operation of moisture profile system.
See also Basis weight (CD) variations.