Abstract: A web of paper or paperboard is manufactured by first forming a base web that is dried on the press section of papermaking machine. The base web is further dried on the dryer section of the papermaking machine and a base web speed differential, or draw, is set between the press section and the first dryer cylinder group of the dryer section, whereupon at least one surface of the web is surface sized. The draw is set to 3% maximum, and a surface size furnish is applied having a solids content of at least 15% of the total amount of size components and liquid in the furnish.

Abstract: A headbox, for example, in a pulp or board machine, is suitable for high basis weights which are over 400 g/m2 and for high fiber suspension consistencies which are in a range of 2–5%. The headbox has a turbulence part (1), into which a fiber suspension flows from a tube bank (2), and a slice part (3) which is situated after the turbulence part and from which the fiber suspension flows to a forming section of a fibrous web. The turbulence part (1) of the headbox has at least two passages (5, 6), which converge in the flow direction of the fiber suspension towards the slice part (3). In that connection, the fiber suspension flow is first fluidized in a tortuous turbulence passage part (11) and, after that, it decelerates in another widening deceleration passage (12).

Abstract: A surface-sized paper web is made by supplying pulp from a headbox (100) where additives and/or fillers and/or fines are admixed into the pulp, to the wire section (200), where water is removed. The web is guided from the wire section (200), to the press section (300), the front drying section (400), is surface-coated in the coating section (500) dried in the post-drying section (600), and reeled by a reeler (800). In the headbox (100) starch and optionally hydrofobic size are admixed or layered into the pulp, so that on at least one side of the web an essentially dense surface is formed, on which in surface-coating a coating paste is spread out, which has a high dry matter content, whereby a bond is achieved in direction z inside the web in between the base paper and the surface-coating layer spread out on the surface.

Abstract: A headbox, for example, in a pulp or board machine, is suitable for high basis weights which are over 400 g/m2 and for high fibre suspension consistencies which are in a range of 2-5%. The headbox has a turbulence part (1), into which a fibre suspension flows from a tube bank (2), and a slice part (3) which is situated after the turbulence part and from which the fibre suspension flows to a forming section of a fibrous web. The turbulence part (1) of the headbox has at least two passages (5, 6), which converge in the flow direction of the fibre suspension towards the slice part (3). In that connection, the fibre suspension flow is first fluidized in a tortuous turbulence passage part (11) and, after that, it decelerates in another widening deceleration passage (12).

Abstract: A stock feed system for a multi-layer headbox and a method in the operation of a multi-layer headbox in which into each inlet header of the multi-layer headbox, a stock concept is passed which has been produced out of the same fresh stock by adding the necessary chemicals and fillers to separated portions of the fresh stock.

Abstract: A profile bar for a discharge opening of a head box of a paper machine, by means of which the profile of the discharge jet from the paper machine is controlled. The profile bar may be connected to adjustment spindles, by means of which the profile bar can be bent in a plane transverse to a direction of flow of the discharge jet. Bending stiffness of the profile bar in the direction of bending to be achieved by means of the adjustment spindles, is arranged to be substantially lower within areas facing the adjustment spindles than at a middle of an area between the adjustment spindles. Transverse sawings or recesses may be made into the profile bar with a spacing substantially denser than the spacing between the adjustment spindles or equivalent. Alternatively, the profile bar may be provided with projections to which the adjustment spindles are attached, with the height of the projections being greater than a maximum height of the profile bar in the space between the projections.

Abstract: Method and apparatus in the head box of a paper machine for controlling the distortion of fibre orientation in the paper web comprise an arrangement wherein by-pass flows of pulp suspension are passed through opposite passages lateral of the turbulence generator preceding the slice portion or discharge channel of the head box. The magnitude and/or the mutual relationship of the by-pass flows is adjusted to control the distortion of the fibre orientation in that the by-pass flows produce a transverse flow in the discharge flow of the pulp suspension from the head box, the speed of which compensates for the distortion of the fibre orientation.

Abstract: Apparatus for damping pressure and consistency perturbations occurring in the pulp suspension flow to the headbox of a paper making machine including an enclosed damping tank defining therewithin a space for a volume of air and a space for the pulp suspension such that the pulp suspension and the air volume have direct interfacing contact. Longitudinally extending distribution and collecting header means are disposed within the tank for conducting the flow of pulp suspension into and out of the tank, respectively. Each of the distribution and collecting header means define a flow passage for the pulp suspension, which passages fluidly communicate with the pulp suspension space within the damping tank through an elongate, continuous slit. Damping or attenuation of the pressure perturbations in the pulp stock flow is achieved through the interaction of the surface of the pulp stock with the air volume while the consistency perturbations are damped through the action of a plural delay principle.

Abstract: An approach pipe system which delivers pulp suspension to the headbox of a paper machine includes a tank having in its interior an upper gas space and a lower liquid space adapted to contain a liquid the upper surface of which contacts the gas in the gas space. In its interior this tank carries a flexible diaphragm which defines with the tank a flow space separated from the liquid space by the flexible diaphragm. A supply pipe communicates with this flow space for delivering a pulp suspension thereto while a discharge pipe also communicates with the flow space for receiving a pulp suspension therefrom and for continuing the travel of the pulp suspension to a headbox. The gas in the gas space acts through the liquid in the liquid space on the diaphragm to damp pressure and flow rate disturbances in the pulp suspension flowing toward the headbox.