摘要:
A headbox for a paper machine is characterized by having: at least one machine-wide channel region which defines a main direction of flow; a region for the production of turbulence; a plurality of feed lines distributed over the machine width and discharging into the headbox channel region; an adjusting device in each feed line for controlling the quantity of flow; an angle .alpha. between the main direction of flow and the feed line; and the angle .alpha. being selected in such a manner that, regardless of the amount fed by the feed line, the total volumetric flow in the region directly downstream of the feed line remaining constant.
摘要:
The invention concerns a method of controlling the relative flow speed of the layers in a multi-layer headbox with laminae mounted torque-free between upper and lower lips which are stationary when in operation. The invention is characterized in that a difference in speed is produced between the individual layers by causing the static pressure to change differently in the different layers.
摘要:
A nozzle of a multilayer headbox wherein the headbox includes a nozzle for distributing the stock suspension on a wire. The nozzle is subdivided by at least one machine-wide fin, the fin forming with the nozzle at least two machine-wide nozzle ducts. At least the mean value of the clearance of at least one nozzle duct diminishes steadily in the flow direction, the percentage decrease of the clearance in the fluidically essential area of the nozzle being at least twice as large as in the starting area of the nozzle.
摘要:
A nozzle of a multilayer headbox wherein the headbox includes a nozzle for distributing the stock suspension on a wire. The nozzle is subdivided by at least one machine-wide fin, the fin forming with the nozzle at least two machine-wide nozzle ducts. At least the mean value of the clearance of at least one nozzle duct diminishes steadily in the flow direction, the percentage decrease of the clearance in the fluidically essential area of the nozzle being at least twice as large as in the starting area of the nozzle. The fin has downstream end area of decreasing thickness immediately preceded by an area of increasing thickness.
摘要:
A paper machine headbox having divided sections for feeding pulp suspensions with different properties therethrough includes a single inlet line and a plurality of feed lines connected thereto. In at least one of the feed lines, there is a separation device which separates certain pulp suspension components from the pulp suspension flowing therethrough. A discharge line connected to the separation device conveys separated pulp suspension components therefrom. A continuing feed line connected to the separation device conveys the remaining pulp suspension to the headbox.
摘要:
An apparatus and method for variably controlling fluid flow in a closed flow line, especially the flow of a pulp suspension through a headbox of a paper-making machine, includes guiding fluid through a cavity of a conduit having at least two different cross-sectional profiles. Fluid flow resistance is adjusted by changing the contour of an edge defined by the conduit and a transition step connecting the two cross-sections.
摘要:
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.
摘要:
A method of manufacturing a web of fibers, especially a web of paper. The pulp is uniformly distributed through an outlet over the width of the machine and along a wire or between two wires. Most of the moisture is subsequently extracted from the pulp accommodated on or between the wires at a draining point. Various amounts of retaining agents are added to the pulp at sections across the headbox and the web in order to control the level of retention sectionally.
摘要:
A multi-layer headbox for the production of a multi-layer web of paper has, for instance, three flow planes (I, II, III), each having a pulp feed device (1.1, 1.2, 1.3). In each flow plane a turbulence generator (3) is provided which opens into a nozzle (4). In it there are two plates (5.1, 5.2) which keep two neighboring streams of slurry separate from each other up to the region of the exit slot (8). Each plate is developed as a flexurally soft plate of plastic, the downstream end of which is metal and has a thickness S of at most 0.3 mm. The plastic and metal have a different in coefficients of thermal expansion of
摘要:
The invention relates to a valve or throttling device for a fluid flow, and particularly a flow containing solids, like a flow of pulp suspension. The valve has the following features: A hollow body of substantially rotational symmetry, which is traversed by liquid; the hollow body has a variable passage area which is substantially of rotational symmetry; and a main direction of fluid flow which is substantially axial to the longitudinal axis of the hollow body is provided in the hollow body. A liquid feed to the passage area is provided so that a component of rotation around the direction of the main stream is added to the liquid with reference to the direction of the main stream.