Analytical and computational modeling of twin-wire blade forming

Three very simple, useful, results concerning twin-wire blade forming have been proven by analyzing the global behaviour of the process. For a single blade in a former with fixed incoming and outgoing fabric angles: the integrated pressure pulse is just the product of the conveying wire tension and the total wrap angle around the blade; the displacement of pulp relative to the wire is the integrated pressure pulse divided by the dynamic pressure of the pulp solution; and the change in gap size is given by the product of the average permeability and the integrated pressure pulse, divided by the wire velocity. Numerical simulation of a variety of forming geometries confirmed that the analytical predictions were in error by under 5%.