Abstract: A single- or a multi-layer headbox of a paper or a board machine intended for consistencies of 0.7-2.2% and provided with a flow ratio adjustment device. The adjustment device operates by removing a part of the stock flow from the slice chamber out of the headbox in a manner that does not change the speed or turbulence of the flow going to the slice at any point of the headbox.

Abstract: A method and apparatus for forming a web wherein a fiber suspension from a head box is fed on a section of a forming wire formed by a first, substantially horizontal dewatering zone, and where the web being formed is thereafter led to a second dewatering zone where an upper wire is caused to cover said web, and both wires together with the web between them are led over a turning member. In the twin wire dewatering zone the wires bend upwards. After the turning member the web runs further linearly between the wires obliquely upwards. The web and the lower wire run around a pick-up suction roll and the upper wire leaves the web. The dewatering in the dewatering zones occurs only in one direction, i.e. through the forming wire.

Abstract: A method and apparatus for feeding a fibre suspension onto the wire of a web former through a guiding device consisting of a plurality of guiding channels through which the fibre suspension flows parallelly and which are connected to a slice chamber leading to a slice and extending across the wire of the web former. A means for separating the dilute outer part of the jet of stock flowing in from every single flow channel is disposed downstream of the guiding device. The outer portion is deflected from the direction of flow of the thicker and more homogeneous core part and the latter is allowed to proceed up to the lip substantially maintaining its direction. Thus, a situation is reached, whereby considerably less local consistency variations occur in the lip flow across the head box. Preferably, this means is formed by a plate in which there are openings disposed coaxially with regard to the manifold tubes so that the diameter of the openings of the plate is smaller than that of the openings of the tubes.

Abstract: A system for damping the pressure fluctuations in a paper machine headbox. The headbox applying the damping system comprises an equalizing chamber communicating with an air space, this equalizing chamber having an outlet/outlets for a channel/channels leading to the equalizing chamber as well as an inlet/inlets for a channel/channels leaving the equalizing chamber. The outlet chamber is disposed with regard to the inlet channel so, and the cross surfaces of the outlet and inlet channels have been dimensioned so that the jet of stock flowing out of the outlet and expanding divergently falls substantially inside the boundaries of the inlet.