Abstract: The ledge is arranged transverse to the machine direction in a substantially flexure resistant manner and is adjustable for guiding the wires between which a web of material is formed. The ledge contains a guide surface which faces the wires and has a special contour. For improved control of the pressure changes occurring in the region of the ledge, the ledge contains a supporting member and a pressing member which contains the guide surface. A pressing device is supported at the supporting member and the pressing member can be adjusted in a direction relative to the wires as well as relative to the supporting member by using the pressing device for simultaneously elevating the pressing member and inclining the pressing member with respect to the machine direction. Advantageously the pressing device constitutes a hose which is subjected to a pressurizing medium and thereby deformable.

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.

Abstract: White water at a high speed of current occurs in the region of a forming roll in a paper machine running at a high speed. The white water is caught in a white water trough which is provided with deflection vanes and is carried substantially at the initial speed by means of a duct (1) out of the ground plan of the paper machine to a stilling tower (2) standing adjacent to the paper machine, to feed the inner wall of a screen wall (3) of a screen cage, which wall is arranged in the stilling tower. The wall (3) is curved and has openings (4) for the white water to pass through. They are designed to peel off in layers the film of white water which is sent along the wall (3) and to deflect the jets of white water passing through the openings (4) radially outwards to the wall (3) against an outer wall (5) of the stilling tower (2), where the actual deceleration of the current takes place in several individual jets.

Abstract: In a wet press for dewatering a web of material, for instance a paper web, a contact pressure device is provided which presses against a rotating roll and exerts an incrementally increasing pressure in the direction of travel of the paper web. The contact pressure device comprises only a single pressure element arranged in the direction of travel of the paper web. The pressure element has two or more pressure pockets arranged sequentially in the direction of web travel and which are connected with a common pressure chamber by conduits. The increasing contact pressure is attained by arranging the pressure element unsymmetrically in relation to the pressure chamber. The effective pressure cross-sectional areas of pressure pockets arranged sequentially in the direction of web travel can additionally be reduced in the direction of web travel or the cross-sections of the associated bores can be increased.

Abstract: The flotation apparatus comprising a container having a free liquid level of the fiber stock suspension which is fed essentially horizontally to the container by at least one infeed device. The infeed device contains at least one aeration element having an outlet cross-section located at a predetermined region which is 100 to 600 mm, preferably 50 to 250 mm, below the liquid level of the fiber stock suspension in the container. Between the end of the aeration element and the discharge mouth or opening of the infeed device which opens into the container there can be arranged an essentially horizontally extending starting path for quieting or stabilizing the flow of the fiber stock suspension. This starting path is provided at its initial region with an ascending cover member at which merges a channel having a free liquid level.

Abstract: A press roll contains a stationary roll support or beam and a roll shell rotatable about the stationary roll support, the roll shell being formed of an easily deformable material. The roll shell is supported at a support surface located at the region of the roll support. This support surface can be convex and possess a larger radius than the radius of the roll shell, can be planar or concave. Guide surfaces possessing a convex profile laterally merge at the support surface. The support surface and the guide surfaces are provided with a pressure lubrication and possibly with hydrostatic bearing pockets. A support part or element can be movable in relation to the stationary roll support or beam in the manner of controlled deflection rolls.

Abstract: The flotation apparatus has a vessel or container into which vortex or turbulence channels lead. These vortex channels supply the fiber suspension or stock to the vessel and are provided with at least one stepped enlargement. An air conduit supplying flotation air opens into the vortex channel. The vessel is substantially cylindrical about a vertical axis and is provided in its upper region with a central conduit or pipe for extracting the flotation foam. In the lower region of the vessel a conduit for extracting the recovered good stock is disposed tangentially.

Abstract: In a wet press for dewatering a web of material, for instance a web of paper, a contact pressure device presses against a rotating roll and exerts a pressure which increases in the travel direction of the web of paper. For this purpose, several rows of contact pressure elements are arranged sequentially in the travel direction of the web of paper. In each row the contact pressure elements are arranged side by side transversely to the travel direction of the web of paper. In order to circumvent a differential dewatering at the location of the contact pressure elements and at the gaps between the contact pressure elements of a row, the contact pressure elements of successive rows are shifted or staggered in relation to one another transversely to the web of material such that they mutually overlap. This prevents the arisal of strips in the paper being processed.

Abstract: The headbox contains a nozzle channel merging at a distributor device for the fiber stock suspension. The nozzle channel contains two lip members bounding a slice opening for forming a substantially flat stock jet. At least one of these lip members is subdivided into at least two lip portions which extend over longitudinal sections of the nozzle channel which are located behind one another in the flow direction of the fiber stock suspension and which are adjustably connected with one another and can be fixed in their adjusted position. At least one of these lip portions is adjustable relative to the distributor device and the neighboring lip portion of the same lip member essentially transversely to the stock flow direction towards and away from the oppositely located lip member, in order to change the pattern or course of the cross-sectional area of the nozzle channel. This enables accommodation of the geometry of the nozzle channel to different products and production requirements.

Abstract: A longitudinal wire papermaking machine is disclosed wherein the longitudinal wire is guided in a dewatering region, following a pre-dewatering path, out of a wire plane downwardly over a deflection element and then upwardly over a downwardly domed or arched dewatering element towards the wire plane. The deflection element is arranged at a spacing K=approximately 15 to 80 mm from the dewatering element. The longitudinal wire is guided at the inlet section of the dewatering region, located between its outbound or run-off location at the deflection element and its lowest deflection location, over a negative pressure zone, for instance constituted by a suction chamber, which is effective at its underside. Hence, at the inlet section there is obtained a reduction in the suspension pressure and the fiber stock suspension is guided with an approximately constant total thickness lower into the dewatering region, i.e.

Abstract: A dewatering apparatus contains a longitudinal wire and an additional wire which is guided, conjointly with the longitudinal wire, along a section of such longitudinal wire over a domed or arched surface. This domed or arched surface is formed, for instance, by the jacket or outer surface of a dewatering cylinder arranged within the wire loop of the longitudinal wire. The longitudinal wire is provided with a headbox and extends forwardly and after the dewatering apparatus essentially in a wire plane, above which upwardly rises the domed surface. Both of the wires are guided out of the wire plane over a dewatering shoe arranged within the wire loop of the additional wire towards the domed surface and from such--if desired over a deflection roll arranged beneath the wire plane--again towards the wire plane, where both wires separate from one another.

Abstract: A material web drier containing a device for controlling the gas flow of a drying medium as a function of the actual state of the wet material web which is to be dried, comprising nozzle casings or surfaces containing blow-out or discharge openings arranged in cooperating relationship with respect to the material web. The discharge openings are directed towards the material web and serve for blowing-out the drying medium onto the web. For the purpose of dosing the gas flow or stream effluxing at the nozzle casings or surfaces, there are provided opening and closing elements which free the discharge openings or partially or completely close the same, as desired, whereby it is possible to vary the impingement of the material web by the drying medium selectively at discrete locations or regions thereof, both in the lengthwise and transverse directions of such material web.

Abstract: The separator of the machine is constructed to retain the paper web on the inner (upper) wire upon separation of the two wires. To this end, the separator positions the roll for the outer (lower) wire downstream of the point of separation of the two wires. A suction box can be used in the separator roll to assist in retaining the paper web on the inner wire (FIG. 1). The inner wire extends from the separator along a straight run which defines an angle of less than 90.degree. relative to the straight path traversed by the two wires upstream of the separator.

Abstract: The inflow line to the drying cylinder is provided with a quantity measuring means to determine the amount of steam being delivered to the cylinder as well as a pressure-regulating means for controlling the pressure prevailing in the cylinder. A signal emitter receives a measurement signal from the quantity-measuring means and transmits a control signal to the pressure-regulating means to bring about an adjustment in the pressure. Use is also made of a bypass line and a thermocompressor to draw steam from the condensate-separator to maintain a constant flow of steam in the drying cylinder.

Abstract: The internal ribs of the drying cylinders are formed with cross-sections which are of parabolic shape or substantially parabolic shape in order to obviate any additional thermal stressing of the cylinder. The rib cross-sections are each situated in a zone bounded outwardly by a hexagon which consists of a rectangle of full rib width and a height equal to 0.75 times the rib height and an adjoining trapezium having a width 0.65 times the maximum rib width at the top of the rib and inwardly by a pentagon of a width of 0.7 times the full width at mid-height of the rib and an apex at the maximum height of the rib.