The DuoShake optimizes fiber orientation through high-frequency shaking of the breast roll. The result is good formation with all paper grades and a low tensile strength ratio.
The DuoShake, a reaction force-free shaking unit for all Fourdrinier paper machines, creates a more homogenous distribution of fibers while reinforcing the orientation of the fibers in cross direction. This is accomplished with two rotating imbalance couples arranged on the hydrostatically mounted carriage. The forces released are transmitted by means of a shake rod to the breast roll. Only minimal friction and centering forces are transmitted to the foundation through the system freely oscillating in a horizontal direction, so only the net weight of the DuoShake has to be carried. The imbalances move within an imbalance couple in a counter-rotating direction and through their arrangement cancel out the vertical forces.
Paper quality is increased due to improved formation with the DuoShake in Fourdrinier paper machines. Improvements result in downstream processing, coating, impregnating and printing of the paper.