Patent ID: 7955474
Filing Date: 2011-06-07
Classification: D21F

Abstract:
1. A tube bank apparatus for distributing stock in a headbox of a papermaking machine, said apparatus comprising: a tube having a first and a second portion for the flow therethrough of the stock; said first portion defining a bore for the flow therethrough of the stock, said bore having an upstream and a downstream end; said second portion defining a passage for the flow therethrough of the stock, said passage having an upstream and a downstream extremity, said upstream extremity of said passage cooperating with said downstream end of said bore so that the stock flows from said upstream end to said downstream end of said bore and then through said upstream extremity and then said downstream extremity of said passage; said downstream end of said bore having a cross-sectional area which is less than a further cross-sectional area of said upstream extremity of said passage; and said downstream extremity of said passage having a cross-section of trapezoidal configuration for minimizing wall effect of the tubes and side effect of the tubes and edge tubes on stock flowing out of the tubes of said tube bank apparatus.