Forming Section
Removing as much water as possible early in the papermaking process allows the formation of a stronger, more consistent sheet while reducing web breaks and water removal costs in the press and drying sections. Low vacuum fans efficiency aid in water removal at the foils.
As the sheet moves down the wire, the alignment of the web fibers makes it more difficult to remove water from the sheet. This requires flatboxes to operate at a slightly higher vacuum level and the use of NASH liquid ring vacuum pumps to help remove water.
When the sheet reaches the couch, our pump provides the high vacuum dewatering needed for proper sheet consistency entering the press section. Its unique design allows our pumps to operate at varying vacuum levels, and handle liquid carryover while providing the rugged, reliable performance that you’ve always expected from Nash.
Press Section
Felt conditioning, which is critical to sheet dryness and paper machine runability, requires a vacuum source at each uhle box that can effectively track felt performance and respond to changes in vacuum level over the life of the felt.
As the felt ages, it becomes less permeable and is more resistant to water removal. This requires an increased vacuum level to remove water. For more effective felt conditioning, TAPPI recommends that each felt be serviced by an independent vacuum source.
The inherent operating characteristics of NASH liquid ring vacuum pumps applied to each uhle box service automatically adjusts the operating vacuum levels to provide optimum water removal over the life of the felt.
The water removed during the felt conditioning process contains felt hairs, paper fibers, and chemical contaminants that can cause premature wear of the vacuum pump internal components if not removed before pump inlet.
