System and method of using acoustic foil for enhanced dewatering and formation

Abstract

Methods and apparatus to condition the paper fiber stock of a wet paper web for enhanced dewatering and formation with an acoustic foil assembly used for removing water and redistributing fibers. A plane ultrasonic wave field is employed for interacting with water suspended pulp and paper fiber stock using acoustic techniques to subject particulate suspensions. The continuous process employees a piezoelectric ceramic transducer to selectively deflect flowing paper fiber stock as they penetrate the ultrasonic field. Depending upon the amount of dissolved gas in water, conditioning is obtained using a traveling wave field to improve paper properties for increased productivity and formation quality with headbox components having hydrodynamic optimization for paper and board forming. Acoustic transducers formed within the foil of a forming table control the fluidization of the paper fiber stock of a wet paper web to generate machine direction strain for imposing a shear in the cross-machine direction for increasing the orientation of paper fiber stock in the cross-machine direction. This generates shear layers which would result in cross-machine orientation of fibers and therefore would increase the strength and other physical properties in the CD.

What is claimed is:  
     
         1 . A paper making machine comprising an acoustic foil comprising one or more acoustic transducers formed within the foil of a forming table for controlling the fluidization of the paper fiber stock of a wet paper web to generate machine direction strain for imposing a shear in the cross-machine direction for increasing the orientation of paper fiber stock in the cross-machine direction.  
     
     
         2 . A paper making machine as recited in  claim 1 , wherein a plurality of acoustic transducers are formed within the foil of the forming table.  
     
     
         3 . A paper making machine as recited in  claim 2 , wherein the acoustic transducers control the fluidization of the paper fiber stock as dewatering occurs of the wet paper web progressing along the transducers for paper fiber orientation increasing the elastic content and distribution of strength in the web as between the MD to the CD direction.  
     
     
         4 . A paper making machine as recited in  claim 3 , wherein said plurality of acoustic transducers are energized to promote the CD fiber alignment orientation polar plot in accordance with FIG. 4B.  
     
     
         5 . A paper machine forming table for receiving a paper fiber stock discharged upon a wire component moving in a machine direction (MD), comprising: 
 an information processor;    a foil component below the wire component;    a transducer coupled with said foil component for controlling the fluidization of the paper fiber stock of a wet paper web discharged upon the wire component moving in the machine direction to align paper fibers in the cross-machine direction (CD) as formation occurs in the wet paper web with dewatering being controlled by energizing the transducer coupled with the foil component under the control of the information processor.    
     
     
         6 . A paper machine forming table as recited in  claim 5 , wherein the dewatering of the wet paper web under control of said information processor generates machine direction strain for imposing shear in the cross-machine direction for increasing the orientation of paper fiber stock in the cross-machine direction.  
     
     
         7 . A paper machine forming table as recited in  claim 6 , comprising a plurality of acoustic transducers under the control of said information processor.  
     
     
         8 . A method of forming paper on a forming table for receiving paper fiber stock, comprising: 
 discharging the paper fiber stock on a wire component moving in a machine direction (MD);    enhancing dewatering of the paper fiber stock to form a wet paper web on the wire component by acoustic manipulation of fibers within the wet paper web; and    forming the web product with increased CD fiber alignment in the wet paper web from shear layers generating cross-machine orientation of fibers, the increased CD fiber alignment in the paper fiber stock yielding CD strength in the web product approximately  10 % greater through the use of acoustic manipulation than the CD strength from the resulting CD fiber alignment obtained without the use of acoustic manipulation at the forming table.    
     
     
         9 . A method as recited in  claim 8 , comprising aligning the paper fiber for CD fiber alignment in the paper fiber stock has a fiber orientation polar plot in accordance with FIG. 4B.  
     
     
         10 . A method as recited in  claim 8 , comprising aligning the paper fiber for elastic content of the web product indicates orientation distribution of strength of the web product being substantially uniform from the MD to CD directions.  
     
     
         11 . A method as recited in  claim 8 , comprising acoustic elements under the wire to re-fluidize the initially formed fiber mat, removing the resistance to dewatering, and consequently, increasing the rate of drainage through the forming wire.  
     
     
         12 . A method as recited in  claim 8 , comprising small section of the acoustic elements aligned next to each other in the CD direction under the wire to profile the level of re-fluidizing the initially formed fiber mat, removing the resistance to dewatering in same profile, and consequently, increasing the rate of drainage through the forming wire in the same profile for the purpose of correcting the nonuniform drainage in the forming wire and other nonuniformities and moisture streaks forming downstream of the forming section.