Moisture streaks in dryers

1. Moisture streaks are commonly avoided by over-drying the rest of the sheet.

• this is the usual, but not the recommended, practice.

2. It may be necessary to slow down the machine if it is operating at the limit of the dryer capacity.

• check for broken siphons.

3. Maintain adequate ventilation conditions and balance.

• avoid uncontrolled drafts.

4. Ensure that non-condensables do not build up by:

(a) venting the front of the dryers, if possible.

(b) installing a sufficiently large condenser on the condensate system.

(c) provide non-condensable venting in the condensate evacuation system.

5. Scrape the dryers regularly; avoid streaks due to paper scale.

6. Ventilate pockets adequately.

• if Grewin system is in use, maintain an adequate velocity.
• with newer systems, maintain design flow.
• if Madeleine or similar rolls are in use, use felts of recommended type.

7. Install fabrics on later dryer sections.

8. Check and control felt drying systems.

• check that the heater is giving its designed performance.