Jwi Ltd.

Victor E Hansen

Richard E Pitt

David T Smith

Douglas R McPherson

A process and apparatus for improving stock formation on an open surface paper making machine is described. By the use of both a path for the forming fabric which introduces a controlled level of agitation into the stock, and a low level of vacuum in a suction box extending continuously for at least the major proportion of the forming section, improvements both in paper quality, such as improved wire mark, and in machine operation, such as an improved first pass retention, are obtained.

Continuous controlled drainage

A method and apparatus are disclosed whereby the rate of drainage of the stock on a Fourdrinier paper making machine can be controlled for the full length of an open surface forming section. A continuous sealed drainage box is used from adjacent the head box slice to the end of the forming section, within which the air pressure can be controlled. In the area adjacent the head box slice drainage is hindered by the use of a positive (above ambient atmospheric) pressure, while further along the forming section the pressure is decreased to a negative value (below ambient atmospheric). Improved paper formation and first pass retention are obtained.

Pressure control forming section

A shear roll is situated above an upper surface of a top run of a Fourdrinier fabric such that a lower portion of the shear roll is adapted to penetrate a pulp stock web situated on the Fourdrinier fabric. The shear roll is operated by an external source of power, the source of power adapted to drive the shear roll at a surface speed exceeding a linear speed of the fabric by greater than 3% and less than 8% of the speed of the fabric. The shear roll is situated at a location where a consistency of the pulp stock web considered on a fibre basis situated on the fabric is between 2% and 5 1/2%; and the shear roll adapted to provide a shearing action to fibre bundles and flocs situated in the pulp stock web as the pulp stock web passes between the shear roll and the fabric, there re-working the pulp stock web and re-forming the fibre network and smearing the flocs thereof.

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Jacksonville, FL, United States of America

Victor E Hansen