Date of Award
Bachelor of Science
Paper Science and Engineering
As dewatering of the stock occurs around the screen basket of a Finckh pressurized, inward flow pulp screen, from 0 to 360 degrees, stock mass flow through the outer screen annulus decreases. Some sections of the screen basket hence handle more stock than other sections.
Stock velocity is dependent on mass flow through an area. Stock velocity is critical to fiber orientation, which is in turn critical to screening.
A volute, much like a tapered manifold header, would decrease the area available for stock flow. This will maintain stock velocity around the full circumference of the screen basket.
A volute was designed and installed in the Finckh screen. It did not alter seperation efficiency at .7% consistency. The volute significantly reduced screen variability.
The volute was tried with 1.2% consistency stock. The volute structurally failed by expansion, because of Bernouli forces.
Ryan, Michael J. IV, "Improving the Performance of the Finckh Screen" (1981). Paper Engineering Senior Theses. 384.