Patent ID: 8236137
Filing Date: 2012-08-07
Classification: D21F

Abstract:
1. A headbox for a machine for producing a web of fibrous material from at least one fibrous stock suspension, the web being one of a paper web and a cardboard web, said headbox comprising: a feed device feeding the at least one fibrous stock suspension; a perforated distribution pipe plate arranged immediately downstream from said feed device and having a plurality of channels arranged in a plurality of rows and a plurality of columns; an intermediate channel arranged downstream from said perforated distribution pipe plate, extending over a width of the headbox, and having a plurality of devices for dosing of a fluid in a plurality of partial fluid streams into the at least one fibrous stock suspension in at least one of an adjustable and a controllable manner, said intermediate channel including a common supply channel, said plurality of devices individually being spaced apart from each other in a width direction of the headbox, said plurality of devices individually including a plurality of dosing channels, said plurality of dosing channels including respectively a dosing channel opening and an opening center line, said plurality of dosing channels discharging at different heights and being connected to said common supply channel; a turbulence generator downstream from said intermediate channel and having a plurality of flow channels arranged in a plurality of rows and a plurality of columns; and a headbox nozzle including a nozzle gap, said headbox nozzle being located immediately adjacent to said turbulence generator, the headbox being configured for showing a system pressure loss which is substantially composed of a first pressure loss between said feed device and said intermediate channel and a second pressure loss in said turbulence generator, said second pressure loss and said first pressure loss being in a ratio in a range of 8:1 to 1:1.