The Yankee dryer is a large, steam-heated, pressure vessel that is used in the production of tissue grades. After the tissue sheet is dried by the Yankee dryer and Yankee hoods to its final moisture target, it is creped and removed from the Yankee by the creping doctor. The "dry creping" process is responsible for the bulk, stretch, and softness that are desirable in tissue grades. This course describes what happens to the sheet during dry creping, factors that influence dry creping results, the design and operation of the creping blade, and blade angles and sheet angles associated with the creping blade.
Learning Objectives
- Differentiate between wet crepe and dry crepe
- Describe the dry creping process
- Describe the importance of the Yankee coating in creping
- Describe the purpose of crepe control
- Describe creping blade setup and geometry
- Describe the effect of sheet path angles