Apparatus For Controlling the Consistency of a Flow of Stock Solution

Abstract

An apparatus is disclosed for controlling the consistency of a flow of stock solution flowing from a header to a slice lip of a headbox of a papermaking machine so that the cross machine direction consistency profile of a resultant web is controlled. The apparatus includes a flow channel which is disposed within the headbox between the header and the slice lip. The flow channel has an upstream and a downstream end such that the flow of the stock solution is in a flow direction from the upstream end towards the downstream end of the flow channel. The flow channel includes a primary channel having a first and a second extremity such that the flow of the stock solution is through the primary channel from the first extremity to the second extremity of the primary channel. A supply channel has a first and a second end and is disposed downstream relative to the primary channel for the flow therethrough of a supply portion of the flow of the stock solution. The second end of the supply channel is connected to the slice lip so that the supply portion of the flow of the stock solution flows to the slice lip. A recirculation channel has a first and a second termination, the recirculation channel being disposed downstream relative to the primary channel for the flow therethrough of a recirculation portion of the flow of the stock solution. The second termination of the recirculation channel is connected to the header so that the recirculation portion of the flow of the stock solution flows to the header. A generator is disposed adjacent to the primary channel for generating ultrasonic waves within the flow of the stock solution flowing through the primary channel. The ultrasonic waves move fiber particles suspended within the stock solution for controlling the consistency of the stock solution flowing through the primary channel. Also, an ultrasound absorber is disposed adjacent to the primary channel such that the flow of the stock solution flows in the flow direction within a region disposed between the generator and the absorber so that in operation of the apparatus, when the stock solution is flowing within the region, the fiber particles suspended within the stock solution are deviated from the flow direction. The arrangement is such that the consistency of the stock solution flowing from the primary channel through the supply channel is different from the consistency of the stock solution flowing from the primary channel through the recirculation channel so that the consistency of the supply portion of the stock solution flowing through the slice lip is controlled thereby controlling the cross machine direction consistency profile of the resultant web.

1 . An apparatus for controlling the consistency of a flow of stock solution flowing from a header to a slice lip of a headbox of a papermaking machine so that the cross machine direction consistency profile of a resultant web is controlled, said apparatus comprising:
 a flow channel disposed within the headbox between the header and the slice lip, said flow channel having an upstream and a downstream end such that the flow of the stock solution is in a flow direction from said upstream end towards said downstream end of said flow channel;
 said flow channel including: 
 a primary channel having a first and a second extremity such that the flow of the stock solution is through said primary channel from said first extremity to said second extremity of said primary channel; 
 a supply channel having a first and a second end, said supply channel being disposed downstream relative to said primary channel for the flow therethrough of a supply portion of the flow of the stock solution; 
 said second end of said supply channel being connected to the slice lip so that said supply portion of the flow of the stock solution flows to the slice lip; 
 a recirculation channel having a first and a second termination, said recirculation channel being disposed downstream relative to said primary channel for the flow therethrough of a recirculation portion of the flow of the stock solution; 
 said second termination of said recirculation channel being connected to the header so that said recirculation portion of the flow of the stock solution flows to the header; 
 a generator disposed adjacent to said primary channel for generating ultrasonic waves within the flow of the stock solution flowing through said primary channel, said ultrasonic waves moving fiber particles suspended within the stock solution for controlling the consistency of the stock solution flowing through said primary channel; and 
 an ultrasound absorber disposed adjacent to said primary channel such that the flow of the stock solution flows in said flow direction within a region disposed between said generator and said absorber so that in operation of said apparatus, when the stock solution is flowing within said region, said fiber particles suspended within the stock solution are deviated from said flow direction so that the consistency of the stock solution flowing from said primary channel through said supply channel is different from the consistency of the stock solution flowing from said primary channel through said recirculation channel so that the consistency of said supply portion of the stock solution flowing through the slice lip is controlled thereby controlling the cross machine direction consistency profile of the resultant web. 
   
     
     
         2 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  including:
 a further generator disposed adjacent to said primary channel and laterally relative to said generator for generating ultrasonic waves within the flow of the stock solution flowing through said primary channel, said ultrasonic waves moving fiber particles suspended within the stock solution for controlling the cross machine direction consistency profile of the stock solution flowing through said primary channel;   a further ultrasound absorber disposed adjacent to said primary channel such that the flow of the stock solution flows in said flow direction within a further region disposed between said further generator and said further absorber such that in operation of said apparatus, when the stock solution is flowing within said further region, said fiber particles suspended within the stock solution are deviated from said flow direction so that the consistency of the stock solution flowing from said primary channel downstream from said further region through said supply channel is different from the consistency of the stock solution flowing from said primary channel downstream from said further region through said recirculation channel so that the consistency of a further supply portion of the stock solution flowing through the slice lip downstream from said further region is controlled relative to said supply portion of the stock solution flowing downstream from said region through the slice lip thereby controlling the cross machine direction profile of the resultant web.   
     
     
         3 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  wherein
 said flow direction is approximately parallel to a direction from the header to the slice lip   
     
     
         4 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  wherein
 said primary channel defines a primary conduit of rectangular cross sectional configuration, said primary conduit extending from said first extremity to said second extremity of said primary channel.   
     
     
         5 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  wherein
 said first end of said supply channel extends from said second extremity of said primary channel.   
     
     
         6 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  wherein
 said supply channel is disposed above said recirculation channel.   
     
     
         7 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  wherein
 said supply channel is disposed below said recirculation channel.   
     
     
         8 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  wherein
 said first termination of said recirculation channel extends from said second extremity of said primary channel such that the flow of the stock solution flowing through said primary channel is split into said supply portion and said recirculation portion adjacent to said second extremity of said primary channel.   
     
     
         9 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  further including:
 a control device electrically connected to said generator for controllably altering generation of said ultrasonic waves by said generator.   
     
     
         10 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  further including:
 a device mechanically connected to said generator for controllably altering a location of said generator relative to said primary channel so that generation of said ultrasonic waves within said region by said generator is altered.   
     
     
         11 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  further including:
 a controller electrically connected to said ultrasound absorber for controllably altering absorption of said ultrasonic waves by said absorber.   
     
     
         12 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  further including:
 a control device mechanically connected to said absorber for controllably altering a disposition of said absorber relative to said primary channel so that absorption of said ultrasonic waves by said absorber is altered.   
     
     
         13 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  wherein
 said flow direction within said region is disposed non parallel to a direction from said generator to said absorber.   
     
     
         14 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 1  wherein
 said flow direction within said region is disposed substantially normal to a direction from said generator to said absorber.   
     
     
         15 . An apparatus for controlling the consistency of a flow of stock solution as set forth in  claim 14  wherein
 said direction from said generator to said absorber is substantially normal to said flow direction within said region such that in use of said apparatus, said ultrasonic waves deviate movement of said fiber particles in a component direction which is disposed angularly between said flow direction and said direction from said generator to said absorber.   
     
     
         16 . A method for controlling the consistency of a flow of stock solution flowing from a header to a slice lip of a headbox of a papermaking machine so that the cross machine direction consistency profile of a resultant web is controlled, said method comprising the steps of:
 guiding the flow of the stock solution through a flow channel which is disposed within the headbox between the header and the slice lip, the flow channel including:   a primary channel having a first and a second extremity;   a supply channel having a first and a second end, the supply channel being disposed downstream relative to the primary channel for the flow therethrough of a supply portion of the flow of the stock solution, the second end of the supply channel being connected to the slice lip so that the supply portion of the flow of the stock solution flows to the slice lip;   a recirculation channel having a first and a second termination, the recirculation channel being disposed downstream relative to the primary channel for the flow therethrough of a recirculation portion of the flow of the stock solution, the second termination of the recirculation channel being connected to the header so that the recirculation portion of the flow of the stock solution flows to the header;   generating ultrasonic waves within the flow of the stock solution flowing through the primary channel by an ultrasonic generator, the ultrasonic waves moving fiber particles suspended within the stock solution for controlling the consistency of the stock solution flowing through the primary channel; and   absorbing the ultrasonic waves by an ultrasound absorber disposed adjacent to the primary channel such that the flow of the stock solution flows in the flow direction within a region disposed between the generator and the absorber such that when the stock solution is flowing within the region, the fiber particles suspended within the stock solution are deviated from the flow direction so that the consistency of the stock solution flowing from the primary channel through the supply channel is different from the consistency of the stock solution flowing from the primary channel through the recirculation channel so that the consistency of the supply portion of the stock solution flowing through the slice lip is controlled thereby controlling the cross machine direction consistency profile of the resultant web.   
     
     
         17 . An apparatus for controlling the consistency of a flow of stock solution flowing from a header to a slice lip of a headbox of a papermaking machine so that the cross machine direction consistency profile of a resultant web is controlled, said apparatus comprising:
 a flow channel disposed within the headbox between the header and the slice lip, said flow channel having an upstream and a downstream end such that the flow of the stock solution is in a flow direction from said upstream end towards said downstream end of said flow channel;   said flow channel including:   a primary channel having a first and a second extremity such that the flow of the stock solution is through said primary channel from said first extremity to said second extremity of said primary channel;   a supply channel having a first and a second end, said supply channel being disposed downstream relative to said primary channel for the flow therethrough of a supply portion of the flow of the stock solution;   said second end of said supply channel being connected to the slice lip so that said supply portion of the flow of the stock solution flows to the slice lip;   a recirculation channel having a first and a second termination, said recirculation channel being disposed downstream relative to said primary channel for the flow therethrough of a recirculation portion of the flow of the stock solution;   said second termination of said recirculation channel being connected to the header so that said recirculation portion of the flow of the stock solution flows to the header;   a generator disposed adjacent to said primary channel for generating ultrasonic waves within the flow of the stock solution flowing through said primary channel, said ultrasonic waves moving fiber particles suspended within the stock solution for controlling the consistency of the stock solution flowing through said primary channel;   an ultrasound absorber disposed adjacent to said primary channel such that the flow of the stock solution flows in said flow direction within a region disposed between said generator and said absorber so that in operation of said apparatus, when the stock solution is flowing within said region, said fiber particles suspended within the stock solution are deviated from said flow direction so that the consistency of the stock solution flowing from said primary channel through said supply channel is different from the consistency of the stock solution flowing from said primary channel through said recirculation channel so that the consistency of said supply portion of the stock solution flowing through the slice lip is controlled thereby controlling the cross machine direction consistency profile of the resultant web;   a further generator disposed adjacent to said primary channel and laterally relative to said generator for generating ultrasonic waves within the flow of the stock solution flowing through said primary channel, said ultrasonic waves moving fiber particles suspended within the stock solution for controlling the consistency of the stock solution flowing through said primary channel;   a further ultrasound absorber disposed adjacent to said primary channel and laterally relative to said absorber such that the flow of the stock solution flows in said flow direction within a further region disposed between said further generator and said further absorber such that in operation of said apparatus, when the stock solution is flowing within said further region, said fiber particles suspended within the stock solution are deviated from said flow direction so that the consistency of the stock solution flowing from said primary channel downstream from said further region through said supply channel is different from the consistency of the stock solution flowing from said primary channel downstream from said further region through said recirculation channel so that the consistency of a further supply portion of the stock solution flowing through the slice lip downstream from said further region is controlled relative to said supply portion of the stock solution flowing downstream from said region through the slice lip thereby controlling the cross machine direction consistency profile of the resultant web;   said flow direction being approximately parallel to a direction from the header to the slice lip;   said primary channel defining a primary conduit of rectangular cross sectional configuration, said primary conduit extending from said first extremity to said second extremity of said primary channel;   said first end of said supply channel extending from said second extremity of said primary channel;   said supply channel being disposed above said recirculation channel;   said first termination of said recirculation channel extending from said second extremity of said primary channel such that the flow of the stock solution flowing through said primary channel is split into said supply portion and said recirculation portion adjacent to said second extremity of said primary channel; and   said direction from said generator to said absorber being substantially normal to said flow direction within said region and said further region such that in use of said apparatus, said ultrasonic waves deviate movement of said fiber particles in a component direction which is disposed angularly between said flow direction and said direction from said generator to said absorber.