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US 4,070,238 AGranted
Headbox for delivering a jet of well dispersed fibrous stock
AssigneeAktiebolaget Karlstads Mekaniska Werkstad
InventorDouglas Wahren
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AssigneeAktiebolaget Karlstads Mekaniska Werkstad
InventorDouglas Wahren
Estimating the term…
Finely-mixed stock is produced in a headbox by delivering a multiplicity of separate stock streams at a relatively high velocity into passages defined between closely-spaced planar lamellae which extend parallel to the stock flow and oblique to a medial plane that lies axially and transversely of the fine-mixing stage that contains the lamellae. The stock flows at relatively low velocity in finely-mixed condition from the fine-mixing stage to a discharge nozzle, the axis of which lies at a substantial angle to the axis of the fine-mixing stage. The stock distribution and mixing section and the delivery nozzle of the headbox may be divided axially and transversely into two or more separate compartments for discharge of a jet composed of layers of the same or different stocks to form multi-ply webs. Different fiber orientations in different layers of such a multi-ply web are obtained by orienting the lamellae in the different chambers at substantially different oblique angles to the aforementioned axial-transverse medial plane of the fine-mixing stage.
A headbox for delivering a stock of fibers carried in a liquid to a web former, comprising a stock mixing section which includes (a) a rectifier stage having means defining a multiplicity of closely-spaced flow passages through which the stock flows in separate streams at a substantially higher velocity than the velocities of stock flow in other parts of the mixing section and (b) a fine-mixing stage downstream, relative to the direction of stock flow through the headbox, from the rectifier stage, the fine-mixing stage including closely-spaced planar lamellae disposed (1) substantially parallel to the medial axis in the flow direction of the fine-mixing stage and (2) oblique to a medial transverse plane of the fine-mixing stage that is defined by the said axis and by a medial line perpendicular to said axis and extending transversely of the fine-mixing stage, and a stock delivery nozzle communicating with the mixing section downstream from the fine-mixing stage and defined by opposed converging walls terminating in a slice opening.
Dependencies are inferred from the claim text.