Headbox for the production of paper or paperboard

Abstract

A headbox is provided that comprises at least one first inlet channel adapted to receive furnish comprising fibres, at least one turbulence generator connected to the first inlet channel, a second inlet channel adapted to receive a non-fibrous high consistency composition, and a sliced cone connected to the turbulence generator and the second inlet channel. The first inlet channel and the turbulence generator are arranged so that the furnish is passed through the first inlet channel and further to the turbulence generator and thereafter to the sliced cone. The second inlet channel is arranged so that the non-fibrous high consistency composition is passed through the second inlet channel and directly to the sliced cone bypassing the turbulence generator.

1 . A headbox comprising at least first and second inlet channels, at least one turbulence generator and a sliced cone, wherein the first inlet channel and the at least one turbulence generator are adapted to receive a furnish comprising fibres and wherein the first inlet channel and the turbulence generator are arranged so that the furnish is passed through the first inlet channel and further to the turbulence generator and thereafter to the sliced cone, and wherein the second inlet channel is adapted to receive a non-fibrous high consistency composition and wherein the second inlet channel is arranged so that the non-fibrous high consistency composition is passed through the second inlet channel and directly to the sliced cone bypassing the turbulence generator. 
     
     
         2 . The headbox according to  claim 1  wherein the headbox comprises three inlet channels wherein two of the channels are adapted to receive the furnish comprising fibres and one of the channels is adapted to receive the non-fibrous high consistency composition. 
     
     
         3 . The headbox according to  claim 2  wherein the inlet channels adapted to receive furnish comprising fibres feeds the furnish to at least one turbulence generator and the inlet channel which is adapted to receive the non-fibrous high consistency composition feeds the non-fibrous high consistency composition directly to the sliced cone without subjecting the non-fibrous high consistency composition to turbulence generation. 
     
     
         4 . A multilayer headbox comprising at least one first inlet channel adapted to receive furnish comprising fibres,
 at least one turbulence generator connected to the first inlet channel,   a second inlet channel adapted to receive a non-fibrous high consistency composition,   a sliced cone connected to the turbulence generator and the second inlet channel,   wherein the first inlet channel and the turbulence generator are arranged so that the furnish is passed through the first inlet channel and further to the turbulence generator and thereafter to the sliced cone, and   wherein the second inlet channel is arranged so that the non-fibrous high consistency composition is passed through the second inlet channel and directly to the sliced cone bypassing the turbulence generator.   
     
     
         5 . The headbox according to  claim 4  wherein the headbox comprises three inlet channels wherein two of the channels are adapted to receive the furnish comprising fibres and one of the channels is adapted to receive the non-fibrous high consistency composition. 
     
     
         6 . The headbox according to  claim 5  wherein the inlet channels adapted to receive the furnish comprising fibres feeds the furnish to at least one turbulence generator and the inlet channel which is adapted to receive the non-fibrous high consistency composition feeds the non-fibrous high consistency composition directly to the sliced cone without subjecting the non-fibrous high consistency composition to turbulence generation. 
     
     
         7 . The headbox according to  claim 5  wherein the channel adapted to receive the non-fibrous high consistency composition is in the middle of the headbox and the two inlet channels adapted to receive furnish comprising fibres are outer inlet channels of the headbox.