| 摘要 |
PURPOSE: To make paper having excellent quality by increasing dispersing uniformity of paper raw material through a steeply contracting/steeply extending element placed in a channel flow path of a headbox. CONSTITUTION: In a multichannel-type or a single channel-type headbox in a paper machine, a channel flow path is constructed by placing at least more one pair of a steeply contracting/steeply extending element A having a steeply contracting flow path 14 having a relation of a flow path height before the contraction T and a flow path height after the contraction (t) as: (t)=(0.25-0.6)T and a contraction angle:θ1 =90-180 deg., a steeply extending part 15 extending with an extending angle:θ2 =90-180 deg. and the flowing path height from (t) to T and a dispersing chamber 16 defined by the flow path height T and a length L: L=(3-5)T at downstream of a rectifier part 9 of the channel flow path, and further a gentle contracting part and a gentle extending part at the more downstream of the element A. The paper raw material is introduced into the above steeply contracting/steeply extending element A from a tube 4 through the flow straightening part 9 and steeply accelerated, then flock is drawn to the flow direction to be uniformly dispersed.
|
