Headbox for a machine for producing a fibrous web

Abstract

A headbox for a machine for producing a fibrous web, in particular a paper, cardboard or tissue web from at least one fibrous stock suspension, includes a feeding device for feeding the at least one fibrous stock suspension; a perforated distribution pipe plate which is arranged immediately downstream from the feeding device in the flow direction of the at least one fibrous stock suspension and which includes a plurality of flow channels arranged in rows and columns; an intermediate channel which is arranged immediately downstream from the perforated distribution pipe plate in the flow direction of the at least one fibrous stock suspension and which extends in a width direction of the headbox and includes two walls, for example having the width of the machine; a turbulence generator which is arranged immediately downstream of the intermediate channel in the flow direction of the at least one fibrous stock suspension and which has a plurality of flow channels arranged in rows and columns; and a headbox nozzle which is arranged immediately downstream of turbulence generator in the flow direction of the at least one fibrous stock suspension and which has a nozzle gap. Feeding device, perforated distribution pipe plate and intermediate channel are arranged in a first alignment plane, and turbulence generator and headbox nozzle are arranged in a second alignment plane. The two alignment planes form an angle in the range of >90 and <180°, for example ≧100 and ≦170°, or ≧110 and ≦160°.

1 . A headbox for a machine for producing a fibrous material web from at least one fibrous stock suspension, the headbox comprising:
 a feeding device for feeding the at least one fibrous stock suspension;   a perforated distribution pipe plate arranged immediately downstream from said feeding device in a flow direction of the at least one fibrous stock suspension includes a plurality of flow channels arranged in a plurality of rows and columns;   an intermediate channel arranged immediately downstream from said perforated distribution pipe plate in said flow direction of the at least one fibrous stock suspension extends in a width direction of the headbox and includes two walls, said feeding device, said perforated distribution pipe plate and said intermediate channel being arranged in a first alignment plane and said intermediate channel including a plurality of metering devices for metered addition of a fluid in a plurality of partial fluid streams into the at least one fibrous stock suspension on at least one of said two walls and spaced apart from each other in said width direction and a longitudinal direction of the headbox, each individual of said plurality of metering devices including a metering channel having a metering channel opening and a metering channel center line, said metering channel opening being aligned such that said metering channel center line impinges on said turbulence generator to form an impingement point;   a turbulence generator arranged immediately downstream of said intermediate channel in said flow direction of the at least one fibrous stock suspension has a plurality of flow channels arranged in a plurality of rows and columns; and   a headbox nozzle arranged immediately downstream of said turbulence generator in said flow direction of the at least one fibrous stock suspension has a nozzle gap, said turbulence generator and said headbox nozzle being arranged in a second alignment plane, said first alignment plane and said second alignment plane forming an angle in a range of approximately between >90 and <180°.   
     
     
         2 . The headbox according to  claim 1 , wherein the headbox for producing the fibrous material web is for producing one of a paper, cardboard and a tissue web. 
     
     
         3 . The headbox according to  claim 1 , wherein said two walls of said intermediate channel and the machine for producing the fibrous material web have a width which is the same. 
     
     
         4 . The headbox according to  claim 1 , wherein said angle is in a range of approximately between ≧100 and ≦170°. 
     
     
         5 . The headbox according to  claim 4 , wherein said angle is in a range of approximately between ≧110 and ≦160°. 
     
     
         6 . The headbox according to  claim 1 , wherein said plurality of metering devices for addition of said fluid in said plurality of fluid streams into the at least one fibrous stock suspension are for controlled and metered addition of said fluid. 
     
     
         7 . The headbox according to  claim 6 , wherein said metering channel opening of said individual metering device is aligned such that said metering channel center line impinges approximately centered between said plurality of columns of two adjacent of said plurality of flow channels onto said turbulence generator to form said impingement point. 
     
     
         8 . The headbox according to  claim 7 , wherein said metering channel opening of said individual metering device is aligned such that said metering channel center line impinges centered between said plurality of columns of two adjacent of said plurality of flow channels onto said turbulence generator to form said impingement point. 
     
     
         9 . The headbox according to  claim 7 , wherein said flow channels of said turbulence generator arranged in one of said plurality of rows feature a row separation and said metering channel center lines of said metering channels which are allocated to said flow channels of said turbulence generator located in said one of said plurality of rows feature a row separation of said metering channel center lines, said row separation of said metering channel center line assuming one of the same and double a value of said row separation of said flow channels of said turbulence generator. 
     
     
         10 . The headbox according to  claim 9 , wherein said metering channel opening of said metering channel of said individual metering device is aligned such that said metering channel center line impinges one of outside and inside said row of adjacent flow channels of said turbulence generator when forming said impingement point onto said turbulence generator. 
     
     
         11 . The headbox according to  claim 10 , wherein said flow channels of said turbulence generator arranged in one column of said plurality of columns feature a column separation of said flow channels and said metering channel center lines of said metering channels of said metering devices join at different heights allocated to said flow channels of said turbulence generator located in said one column feature a column separation of said metering channel center lines, said column separation of said metering channel center lines assuming one of the same and double a value of said column separation of said flow channels of said turbulence generator. 
     
     
         12 . The headbox according to  claim 1 , wherein said flow channels of said turbulence generator located in two adjacent of said plurality of rows are arranged offset relative to each other. 
     
     
         13 . The headbox according to  claim 12 , wherein said flow channels of said turbulence generator located in said two adjacent of said plurality of rows are arranged center-offset relative to each other. 
     
     
         14 . The headbox according to  claim 1 , wherein all of said metering channels of said plurality of metering devices are connected with a common supply channel. 
     
     
         15 . The headbox according to  claim 13 , wherein each of said metering channels of said individual metering devices is connected with its own supply channel. 
     
     
         16 . The headbox according to  claim 1 , wherein said metering channel opening of said metering channel of each of said individual metering devices is located at a vertical and at least approximately uniform distance in a range of approximately between 1 to 50 mm from said turbulence generator. 
     
     
         17 . The headbox according to  claim 16 , wherein said distance is in a range of approximately between 10 to 30 mm from said turbulence generator. 
     
     
         18 . The headbox according to  claim 17 , wherein said distance is in a range of approximately between 3 to 30 mm from said turbulence generator. 
     
     
         19 . The headbox according to  claim 1 , wherein said metering channel of said individual metering devices features at least in part one of a constant and an intermittently enlarging cross sectional inside surface. 
     
     
         20 . The headbox according to  claim 1 , wherein said individual metering devices include a metering pipe. 
     
     
         21 . The headbox according to  claim 20 , wherein said metering channel of said individual metering devices has a rotationally symmetrical cross-sectional inside surface along its respective metering channel center line. 
     
     
         22 . The headbox according to  claim 21 , wherein said metering pipe of said individual metering devices has a rotationally symmetrical outside surface with a diameter in a range of approximately between 3 to 25 mm. 
     
     
         23 . The headbox according to  claim 22 , wherein said diameter is in a range of approximately between 4 to 16 mm. 
     
     
         24 . The headbox according to  claim 23 , wherein said diameter is in a range of approximately between 5 to 10 mm. 
     
     
         25 . The headbox according to  claim 1 , wherein said fluid consists of one of at least water and at least one fibrous stock suspension having a concentration different than an average concentration of the at least one fibrous stock suspension flowing through the headbox. 
     
     
         26 . The headbox according to  claim 25 , wherein said fluid consisting of said water is one of white water and clarified water. 
     
     
         27 . A machine for producing a fibrous material web, the machine comprising:
 a headbox comprising;   a feeding device for feeding the at least one fibrous stock suspension;   a perforated distribution pipe plate arranged immediately downstream from said feeding device in a flow direction of the at least one fibrous stock suspension includes a plurality of flow channels arranged in a plurality of rows and columns;   an intermediate channel arranged immediately downstream from said perforated distribution pipe plate in said flow direction of the at least one fibrous stock suspension extends in a width direction of the headbox and includes two walls, said feeding device, said perforated distribution pipe plate and said intermediate channel being arranged in a first alignment plane and said intermediate channel including a plurality of metering devices for metered addition of a fluid in a plurality of partial fluid streams into the at least one fibrous stock suspension on at least one of said two walls and spaced apart from each other in said width direction and a longitudinal direction of the headbox, each individual of said plurality of metering devices including a metering channel having a metering channel opening and a metering channel center line, said metering channel opening being aligned such that said metering channel center line impinges on said turbulence generator to form an impingement point;   a turbulence generator arranged immediately downstream of said intermediate channel in said flow direction of the at least one fibrous stock suspension has a plurality of flow channels arranged in a plurality of rows and columns; and   a headbox nozzle arranged immediately downstream of said turbulence generator in said flow direction of the at least one fibrous stock suspension has a nozzle gap, said turbulence generator and said headbox nozzle being arranged in a second alignment plane, said first alignment plane and said second alignment plane forming an angle in a range of approximately between >90 and <180°.