James River-Norwalk, Inc.

James River-dixie/northern, Inc.

Robert S Thut

Bruce W Janda

James O Cheshire

Robert J Marinack

Douglas L Lindgren

John T Larkey

Ray E Jostad

In a papermaking or like operation wherein fibers are supplied to a headbox in a foamed furnish, a method of controlling furnish flow including the steps of controllably advancing the furnish along a flow path to the headbox, measuring the volume flow rate of furnish through a fixed cross-sectional area in the path with a magnetic flowmeter, combining the flow rate measurement at least with measured values of furnish density and pressure in the path and with a reference pressure value to obtain a corrected volume flow rate value, and controlling the advance of furnish in the path upon departure of this corrected value from a desired value so as to change the corrected value toward the desired value. A temperature measurement can also be combined with the other measured values, and with a reference temperature value, in obtaining the corrected flow rate value. If the headbox has a variable slice opening, a measured value of slice opening dimension can be combined with the corrected volume flow rate value to ascertain the discharge velocity of the furnish issuing from the headbox, and the control of furnish advance can be made responsive to departure of this ascertained velocity from a desired value so as to charge the ascertained velocity toward the desired value. The method can be practiced to control plural furnish flows supplied to a multichannel headbox, with the corrected flow rate values of the individual flows being summed to obtain a total flow rate or ascertained velocity value for control of overall flow conditions. Apparatus for controlling a flow or flows of foamed furnish includes a magnetic flowmeter, devices for making and transmitting measurements of at least furnish density and pressure, a control unit for receiving and combining the measurements thus made by the flowmeter and the other devices, and furnish flow control means such as a variable speed pump controlled by signals from a control unit.

Method for controlling feed of foamed fiber slurries

Apparatus and method for the manufacture of a non-woven fibrous web such as paper from a dispersion of fibers in a foamed liquid in which fiber furnished in a foamed liquid comprising a solution of surfactant in water is discharged from a headbox into the nip of a twin forming wire prior to its passage over a forming roll. The water-surfactant solution is drained from the web and recycled as a foamed liquid containing about 65% air in the form of bubbles of from about 20 to about 200 microns in diameter. The foamed liquid is directed into a mix tank wherein a slurry containing fiber at 20% to 55% solids is added and mixed. The mixture is pumped to the headbox and into the nip of the forming wires.

Method for manufacture of a non-woven fibrous web

Apparatus and method for the manufacture of a non-woven fibrous web such as paper from a dispersion of fibers in a foamed liquid. In a preferred embodiment, a solution of surfactant in water is initially discharged from a headbox into the nip of a twin forming wire prior to its passage over a curvilinear path defined by a forming roll. The water-surfactant solution is caused repeatedly to pass through the outer one of the twin forming wires until there is created, and stored in a silo, a foamed liquid containing about 65% air in the form of bubbles of from about 20 to about 200 microns in diameter. The foamed liquid is directed from the silo into a mix tank wherein a slurry containing fibers at 20% to 55% solids is added and mixed. The mixture is pumped to the headbox and into the nip of the forming wires. The outer wire retains the fibers while passing and again foaming the liquid for return to the silo and the mix tank for addition of fibers and return to the headbox. The process is continued in formation of a fibrous web. In an alternative embodiment, the curvilinear path is defined by an arcuate surface that is fluid pervious so that the solution to be foamed may pass through both the inner and outer wires. A further alternative embodiment utilizes a single forming wire for receiving the solution prior to passage over a suction breast roll which receives the solution then centrifuges it outwardly in formation of foamed liquid.

Apparatus and method for the manufacture of a non-woven fibrous web

Apparatus and method for the manufacture of a non-woven fibrous web, such as paper, from a dispersion of fibers in a foamed liquid. In a preferred embodiment, a solution of surfactant in water is initially discharged from a headbox into the nip of a twin forming wire prior to its passage over a curvilinear path defined by a forming roll. The water-surfactant solution is caused repeatedly to pass through the outer one of the twin forming wires until there is created, and stored in a silo, a foamed liquid containing about 65% air in the form of bubbles of from about 20 to about 200 microns in diameter. The foamed liquid is directed from the silo into a mix tank wherein a slurry containing fibers at 20% to 55% solids is added and mixed. The mixture is pumped to the headbox and into the nip of the forming wires. The outer wire retains the fibers while passing and again foaming the liquid for return to the silo and the mix tank for addition of fibers and return to the headbox. The process is continued in formation of a fibrous web. In an alternative embodiment, the curvilinear path is defined by an arcuate surface that is fluid pervious so that the solution to be foamed may pass through both the inner and outer wires. A further alternative embodiment utilizes a single forming wire for receiving the solution prior to passage over a suction breast roll which receives the solution then centrifuges it outwardly in formation of foamed liquid.

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Green Bay, WI, United States of America

Robert S Thut