Paper Machine Drying Challenges Brought About By the Use of Recycled Fiber, 1992 Engineering Conference Proceedings

As the use of recycled fiber on modem paper machines increases, the ability to keep the paper machine components clean enough to not affect the paper making process becomes a major task for paper mills, as well as equipment suppliers. The areas which must be addressed include the controlling of the drying process to minimize the deposit of contaminants on the dryer surface, the removal of the contaminants from the surfaces, and the use of felt conditioning and cleaning to maintain a uniform drying environment.

To control the drying process, the steam and condensate system must be designed to allow for a gradual heat-up of the sheet. To remove contaminants from the dryer surface, doctors must be strategically located and maintained, and other cleaning equipment must be available for use during machine outages.

To maintain fabric cleanliness and uniformity, continuous cleaning and conditioning must be built into the equipment, and batch cleaning methods must also be available. If all of these factors are not considered by the operators and suppliers alike, the contamination of the machine will greatly affect sheet runnability and quality. This paper will discuss methods that can be used to control each of these problem areas.