Contact Surface
Pressure application hardware consists of a shoe and a flexible belt designed to provide a longer duration of force than traditional roll presses. The extended-nip press increases the dwell time of the paper web in the nip, which facilitates higher water removal without crushing the fibre structure. This technology is common in the production of linerboard and fluting where bulk and strength are essential.
Drying Load
Removing more water mechanically reduces the amount of steam required in the dryer section to reach the target moisture level. Because mechanical pressing is more energy efficient than thermal evaporation, the presence of an extended-nip press can increase the overall speed of the production line. Higher dryness levels entering the cylinders also improve the surface smoothness of the board.
The specific pressure curve applied across the shoe determines the final density of the sheet.
Fibre Bonding
The gentle and sustained pressure of the shoe allows for better conformability of the fibres, which enhances the internal bond strength of the material. Unlike conventional rolls that can damage fibres at high pressure, this configuration maintains the thickness of the board while maximizing the contact area for hydrogen bonding. It supports the use of lower quality recycled fibres by compensating for their shorter length with better consolidation.
A well maintained belt and lubricant system are necessary to prevent heat buildup and premature wear during continuous operation. The increased surface contact improves the overall stiffness of the finished substrate.
