Abstract: 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 <10.sup.-7 1/K.

Abstract: 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.

Abstract: 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.

Abstract: The present invention involves a headbox and manifold system for producing a multi-ply paper which includes a plurality of mixing systems for generation of stock suspension flows of differing concentrations and a distribution manifold for providing a different stock suspension for each of the plies. For at least one of the plies, two conduits or manifolds are used to carry stock suspensions of differing concentrations thereby permitting the adjustment of the concentration of the stock suspension used to form that ply. Each manifold is fixed to the support structure of the paper making machine and runs transverse to the machine direction. Each of the manifolds is in fluid communication with the movable headbox by means of flexible lines of equal length. After discharge from the flexible lines the stock suspensions are routed through turbulence generators before being discharged from the headbox through a slice nozzle to form a multi-ply paper web.

Abstract: A method for improving the quality of multilayer and multiply papers in the wet section of a paper machine, wherein at least two stock suspensions of different quality are used for producing a paper web. The wire water removed through the paper machine wire is collected in separate vessels and recycled. At least the major part of a first stock suspension is dewatered through a first wire, while at least the major part of a second stock suspension is dewatered through a second wire. The wire water removed through each of the wires is collected, separately from the other wire water, and recycled to the stock suspension of the same layer.

Abstract: 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.

Abstract: 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.

Abstract: To regulate the basis weight cross section of the fiber suspension dispensed by the outlet of a headbox of a paper making machine onto the screen or screens of the following forming section, the headbox is sectioned across the width of the machine with individual first sections of fiber suspension across the width. The fiber suspension on the screen(s) in the following forming section is drained and the drained filtrate is collected in second sections respectively generally corresponding to the first sections of the headbox. The removed sectioned filtrate is recycled to the respective sections of the headbox and is mixed with the suspension normally entering the headbox to regulate and make more uniform the basis weight cross section of the fiber suspension.

Abstract: A throttle device for stock suspensions in a paper machine including a feed line, a drain line and a spatially variable cavity connecting the feed line and drain line with each other. The cavities provided with a plurality of nestable walls in which the nesting effects a lengthening of the flow path.

Abstract: 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.

Abstract: A throttle device for stock suspensions in a paper machine including a feed line, a drain line and a spatially variable cavity connecting the feed line and drain line with each other. The cavities provided with a plurality of nestable walls in which the nesting effects a lengthening of the flow path.

Abstract: 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.

Abstract: 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.

Abstract: The invention concerns a mixing system for mixing two liquids at the inlet to the headbox of a paper machine with: an inlet line (A) for the first partial volume flow (a); an inlet line (B) for the second partial volume flow (b); an outlet line (C) for the mixture volume flow (c) with the flow resistance (W); a mixing angle (.alpha.) with the inlet line (A) and the inlet line (B); a main flow angle (.beta.) between the inlet line (A) and outlet line (C); a valve (S) installed in the inlet line (B) for control of the partial volume flow (b). The mixing angle (.alpha.) is selected so that the mixture volume flow (c) remains constant, independent of the partial volume flow (b).