Water removal (CD)

Note: Using the press to overcome faults generated elsewhere in the machine system will lead to more trouble than it overcomes.
1. Maintain a level sheet on the forming table and check for interference from headbox showers.
2. Perform accurate balance grinding and adjustment of drainage elements and deflectors.
3. Maintain even suction across vacuum boxes (flatboxes).
— use appropriate hole size so that holes will not fill.
— ensure that the construction below the covers does not retard drainage.
— check that piping and seal tank are large enough.
4. Check that suction couch box is flush against shell and sealing strip.
5. Keep total crowns and crown curves correct for applied load.
6. Prevent leaking at doctors.
7. Keep press felts in good condition and maintain straight seams.
— do not run felts beyond their useful life.
8. Ensure a uniform temperature across dryers.
9. The dryer felts must be in good condition.
— use dryer fabrics or semi-synthetics on later positions.
10. Correct felt tension must be maintained.
11. Eliminate any uncontrolled air currents in dryers.
— in practice, this means a balanced and properly operating ventilation system.
12. Install pocket ventilation.
— either blow rolls or a fixed system with fabrics.
13. If fabrics are fitted, ensure that they are dried out.
— when operating with normal dryer felts, ensure that felt dryers are working and that steam to felt dryers is automatically reduced on a break.
14. The felt stretchers must be free.
15. Dryers must be clean.
— they must be scraped regularly with a heavy scraper.
Related information may be found in Moisture profile, Wet streaks, and Basis weight (CD) variations.