Patent ID: 8075737
Filing Date: 2011-12-13
Classification: D21F

Abstract:
1. A headbox apparatus for a papermaking machine, said headbox apparatus defining a flow path for stock flowing between an upstream location and a downstream slice lip, said apparatus comprising: a plurality of blocks which are anchored within the flow path between the upstream location and the slice lip; each block and an adjacent block of said plurality of blocks defining therebetween a flow tube for the flow therethrough of the stock; said flow tube having an upstream portion having an upstream and a downstream end; said flow tube having a downstream portion having an upstream and a downstream extremity, said upstream extremity of said downstream portion extending from said downstream end of said upstream portion; said downstream portion of said flow tube having a volume which is greater than a further volume of said upstream portion of said flow tube such that when the stock flows from said upstream portion to said downstream portion of said flow tube, the stock is mixed within said downstream portion; each block of said plurality of blocks has a first and a second end; each block having a first portion which extends from said first end of said block; each block having a second portion which extends from said first portion to said second end of said block; said first portion of said block defining a first and a second side, said first side of said first portion being planar, said second side of said first portion being planar, said second side being disposed spaced and parallel relative to said first side; said second portion of said block defining a first and a second face; said first face of said second portion defining a surface and a further surface; said second face of said second portion defining a facing and a further facing; said first face is disposed spaced and parallel relative to said second face, said first face and said second face being spaced apart by a distance which is less than a further distance between said first and second sides of said first portion; said second portion of said block defines a first rib which is disposed between said surface and said further surface, said first rib extending between said first portion and said second end of said block; and said second portion of said block defining a second rib which is disposed between said facing and said further facing, said second rib extending between said first portion and said second end of said block.