Abstract: A headbox of a paper or board machine having an inlet, a distributor for feeding stock suspension to be distributed over the machine width into the inlet. A turbulence generator downstream of the distributor has a hydraulic diameter of less than 17 mm in the downstream end region. The hydraulic diameter is the diameter of individual channels through the turbulence generator. The turbulence generator has channels or plates that define several channels, each in accordance with the desired hydraulic diameter. Dimensions of the hydraulic diameter are disclosed. The turbulence generator has lands at the downstream end. The land area ratio is disclosed. A nozzle or the like downstream of the turbulence generator introduces the stock suspension over the machine width to a wire or wires of the next section.

Abstract: This invention pertains to an elongated gap or extended nip press comprised of two pressing elements whose pressing areas are pressed against each other, wherein each of the press areas is formed of a band-shaped jacket element, with the jacket element moving around carriers and being supported by at least one support element, wherein a change of the length of the press gap or nip and/or of the pressure distribution or pattern in the press gap is accomplished in that the portions of the press elements that form the support surfaces and/or that the support elements of at least one of the pressing elements are displaceable in or against the direction of rotation of the respective jacket element.

Abstract: A drying section of a paper machine includes a plurality of individual drying groups, wherein the drying cylinders of a drying group are served by 2 respective dryer wire or felt that passes over drying cylinders of the drying group and presses a web to be dried against the surface of the drying cylinders. The invention is adapted for either single tier or double tier drying groups. At least one press roll is disposed between and separates two of the drying groups. In one embodiment, the at least one press roll forms a nip with the adjacent drying cylinder, either upstream or downstream, to define a dewatering nip through which the web passes. A dewatering belt passes over the press roll in the nip. The wire for a respective drying group is guided away from the dewatering nip so that only the web and the dewatering belt pass through the press nip. In alternate embodiments, two press rolls may be disposed between the adjacent drying groups, and the two press rolls define a press nip between them.

Abstract: In a double wire former of a paper machine, a first continuous wire (1) is fed onto an at least partially curved guiding surface (4) so as to converge with a second wire (2), wherein the guiding surface (4) is movable in a form-locked manner relative to the wires. After the dewatering section described above, a further guiding surface (7) follows which, in advantageous embodiments, has an opposite sense of curvature and is fixedly located.

Abstract: A drying section of a papermaking machine includes several drying groups with at least one drying screen each. At the end of one drying group and/or at the beginning of the next following drying group, a finishing roller is utilized. A finishing nip is formed between one of two finishing rollers and a finishing roller and a drying cylinder of an adjacent drying group. Only the paper web is conveyed through the finishing nip.

Abstract: A measuring bridge, fixed in place above a moving paper web and disposed crosswise to it, is provided, having a measuring head, movable back and forth--crosswise to the paper web--, for determining the measuring values for judging the thickness of the paper web at the measuring spots or point on top of which the measuring head happens to be. The measuring device, has a process management system, in which a traversing flow program has been installed, in accordance with which the traversing time and/or the reversing time of the measuring head are changed after each traverse of the measuring bridge. Because of this, the frequency of the measurements along the web becomes irregular. This prevents false evaluations of the cross section and, as a consequence, inappropriate control instructions of a control computer.

Abstract: A fiber stock suspension is directed from a guide device through the nozzle chamber of the headbox device and out of the slice opening thereof onto a papermaking machine. This nozzle chamber comprises at least two zones or sections. The first zone subsequent to the guide device possesses a relatively low convergence angle or low angle of wall inclination of the headbox device relative to the direction of flow of the fiber stock suspension. The other or second zone is positioned prior to or immediately upstream of the slice opening and possesses a substantially greater convergence angle or angle of wall inclination. In the first zone subsequent to the guide device, an improved flow stabilization or quieting of the flow of the fiber stock suspension occurs after the deflection of the fiber stock suspension and the creation of turbulence by the guide device. In the second zone prior to the slice opening the fiber stock suspension is strongly accelerated.

Abstract: In a headbox system for a papermaking machine with an adjustable distribution of the fiber stock suspension or pulp over the web width, the flow in the delivery slice is controlled in such a way that, across the web width, also the distribution of the fibers in respect of fiber orientation and quantity has a desired profile. For this purpose, the flow of the fiber stock suspension is controlled such that in the event of a change in the distribution of the fiber stock suspension across the web width, the horizontal component of the flow direction in the delivery slice remains, at all locations, always in the predetermined machine direction and thus transverse flows are avoided and the flow rate in the delivery slice has a predeterminate profile.

Abstract: In a headbox system for a papermaking machine with an adjustable distribution of the fiber stock suspension or pulp over the web width, the flow in the delivery slice is controlled in such a way that, across the web width, also the distribution of the fibers in respect of fiber orientation and quantity has a desired profile. For this purpose, the flow of the fiber stock suspension is controlled such that in the event of a change in the distribution of the fiber stock suspension across the web width, the horizontal component of the flow direction in the delivery slice remains, at all locations, always in the predetermined machine direction and thus transverse flows are avoided and the flow rate in the delivery slice has a predeterminate profile.

Abstract: In a headbox system for a papermaking machine with an adjustable distribution of the fiber stock suspension or pulp over the web width, the flow in the delivery slice is controlled in such a way that, across the web width, also the distribution of the fibers in respect of fiber orientation and quantity has a desired profile. For this purpose, the flow of the fiber stock suspension is controlled such that in the event of a change in the distribution of the fiber stock suspension across the web width, the horizontal component of the flow direction in the delivery slice remains, at all locations, always in the predetermined machine direction and thus transverse flows are avoided and the flow rate in the delivery slice has a predetermined profile.