A method and apparatus for reducing turbulence in a pulp flow stream flowing through a paper making machine headbox includes providing lamellae disposed in a portion of the headbox. A lamella end portion is modified which provides for the flushing of a dead space formed in the wake of the lamella. The modified lamella end portion produces small flow channels which divide the pulp stream flowing past the lamella into a plurality of substreams and guides the substreams into the region of the dead space.
Lamella and headbox of a web production machine. The lamella is formed of at least one high-performance polymer. The at least one high-performance polymer includes high stability, high heat resistance, and good to very good resistance to at least one of alkaline solution and acid. The headbox includes the lamella.
A headbox of a paper machine for distributing stock suspension over the machine width of the paper machine onto a forming or wire section includes a headbox nozzle that extends over the machine width and that has spaced apart top and bottom lips that gradually converge from the stock nozzle inlet toward the nozzle outlet. At least one baffle that extends over the machine width is located in the nozzle between the lips and spaced therefrom. The length of the baffle in the flow direction of the stock suspension is less than twice the maximum spacing or height between the top and bottom lips of the headbox nozzle, which is the spacing between them at the tallest space, typically at the upstream entrance end of the nozzle. In addition, the length of the baffle is at most less than 50% the length of the nozzle. The baffle tapers narrower in height in the flow direction, and the angle of divergence of the top and bottom surfaces of the baffle is less than 5.degree. from the flow direction of the suspension through the nozzle.
