| 摘要 |
In a paper machine headbox, a stock suspension flow passes through turbulence pipes (14an) and is distributed into superimposed layers. Stepped expansion spots (16) of the flow cross-section area of the turbulence pipes (14) or the positions of trailing elements starting from between the pipe rows (Rn) and extending to the slice duct (12) of the headbox control the onset and level of turbulence in each layer. Turbulence is generated in different phases of the flow in different layers by arranging the expansion spots (16) and/or the trailing elements in superimposed layers to be located at different distances from the slice opening (13) of the headbox, whereby a different turbulence prevails at the slice opening (13) in different layers of the stock suspension flow. |
