Compact wet end designs deliver more agile papermaking operations

Since the concept of compact wet end systems for paper machines was introduced at the TAPPI Papermakers' Conference in 1993, the idea has been further developed and now implemented into practice. While some problems were initially anticipated, the concept has - in addition to meeting the original objective of offering agility - proven to offer a number of unanticipated advantages. With seven systems delivered and four in operation, it has been concluded that a compact, hydraulically-closed system is more stable, rather than more unstable, compared to a conventional system with free surfaces in tanks, towers, or vacuum deaerators. There is also confirmation that centrifugal degassing of the white water is sufficient to provide the gaslessness required for quality papermaking. The hydraulic compact system stays cleaner than a system with large volumes, open surfaces, and slow flow. It also offers a simplification which saves energy and investment.