Mini-Encyclopedia of Papermaking Wet-End
Chemistry
Part
Three: Equipment & Unit Operations
Gap Former
In a twin-wire paper forming machine or "gap-former" the jet of furnish from the headbox is directed into the narrowing gap between two forming fabrics. Water is removed in both directions. The rate of water removal may be enhanced by passing the pair of forming fabrics around a roll, over blades, or over vacuum elements. The bi-directional removal of water tends to produce a sheet in which the fines content and appearance of the two sides is very similar. Because the sheet becomes "set" very rapidly within a gap former, the uniformity of furnish emerging from the headbox can be critical.
Request from the webmaster: Our goals include brevity and accuracy. Hopefully we have succeeded with the first goal without sacrificing the second. Please let us know right away if you find an error or omition. Also, please indicate points that need a clearer description.
RETURN TO INDEX PAGE OF ENCYCLOPEDIA
This page is maintained by Martin hubbe, Associate Professor of Wood and Paper
Science, NC State University, m_hubbe@ncsu.edu .