Abstract: The stock stream of a pre-cleaned paper stock suspension is sub-divided into extremely small partial jets in a chamber of a compartment. Each such partial jet or stream has a throughflow volume of approximately 50 liters/min. to 80 liters/min. and is directed with great turbulence against an impact wall within the closed chamber of the compartment at jet velocities in the order of about 10 m/sec. to 12 m/sec. and at an absolute pressure of about 0.5 to 0.8 bar absolute, the partial jets then being completely sprayed at such impact wall. The paper stock suspension which is to be deaerated has as large as possible surface area, so that the air is efficiently released at a negative pressure or vacuum of approximately 0.05 bar prevailing in the chamber and then can be suctionally removed. The division of the stream of the paper stock suspension into partial jets is accomplished by a distributor through which extends a predetermined number of throughflow openings defined by bores.

Abstract: A dewatering device for the web-forming or wet section of a papermaking machine comprises foils arranged transverse to a forming wire, that is to say, extend in the cross-machine direction. Force or powering elements act upon the foils so as to exert a force or pressure upon the forming wire, and thus, bring about dewatering and sheet formation of a layer of fiber stock suspension reposing upon the forming wire. The force elements are constructed and positioned such that additional moments are generated which counteract tilting moments produced by the frictional force present between the foils and the forming wire. In certain arrangements, the force elements also can be interconnected with one another.

Abstract: A twin wire former wherein the forming turbulence of a first forming section is quieted by a main forming roller. Behind the main forming roller, as viewed with respect to a predetermined direction of travel of the forming wires, there is accomplished a further forming of the paper web or sheet from the fiber stock suspension in a second forming section. Due to this arrangement there is possible optimum formation of the paper web or sheet with the use of very little dilution water for the fiber stock suspension. Additionally, due to intensive shear forces present in the second forming section flocks formed in the fiber stock suspension and the paper web or sheet at the region of the main forming roller, can be eliminated so that the structure of the paper web or sheet is made more uniform.

Abstract: The de-watering apparatus for a two-wire paper machine is constructed in such a manner that following the convergence of both wires, firstly, a uniform pressure at a forming roll is exerted on the suspension layer located between the wires. Subsequently, both wires pass de-watering rails which may be located in the upper and/or the lower wire. In this case, an under-pressure is exerted at least at the rails located in the upper wire. At least one further de-watering member then follows before both wires are separated again. The de-watering apparatus can also be used after a preliminary de-watering section, for example an endless wire, and also in the direct vicinity of a head box.

Abstract: Calendering takes place in a calendering zone which operates under pressure with application of temperature and moisture. The desired smoothness is achieved with a correspondingly long dwell time of the material web in a correspondingly long calendering zone in view of the speed of web travel. A web which is still wet is guided between parallel heatable surfaces which are arranged on both sides of the web and face each other through the web and can each be pressed against the web. The surfaces are designed to form and hold a given precise contour of the calendering zone over its full length. One surface is constructed e.g. as a casing of a heated roller and the second surface is constructed as an endless flexible belt which can be pressed in a direction towards the roller casing by means of a concave supporting element. If wished, the web can be calendered on both sides with the method.

Abstract: An extended drainage strip (3) is placed next to the primary sieve (5) of a double-sieve mold. It has a liquid-intake space (2), which is disposed between the part of the surface (4) facing the sieve and the sieve (5). Disposed next to the other sieve (6) is at least one adjustable strip (7) arranged so that it can be placed opposite the intake space (2). Intake space (2) has a cross-sectional size that increases, if necessary, in the direction in which the liquid flows. By pressing the adjustable strip (7) against the intake space (2) of the extended strip (3), the shape of the intake space (2) can be controlled, and the suction or intake of the liquid in the intake space (2) is regulated. One object is to achieve steadily increasing suction in the flow direction. This result assists in preventing undesired pressure surges. The drainage device is simplified and thus easy to monitor. Drainage proceeds carefully, with higher retention of fine particles in the sheet of material between the sieves.

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: 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: A method and machine for fabricating building boards or the like, especially asbestos cement plates, contains a turbulence device having at least one channel with a step-shaped widened portion. The channel either has the form of a slot extending over the entire width of the machine or there are provided a series of cylindrical bores forming essentially parallel channels. An intermediate chamber or compartment merges with the channel or channels. Leading from the intermediate chamber is an outlet gap to the upper surface of a felt band.

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 paper making machine contains a filter or screen cylinder and an external filter or wire guided over guide rolls, the external filter or wire being trained about the filter cylinder. The stock suspension is introduced by means of a free jet-headbox between the cylinder and the external filter, into an essentially linear portion of the external filter or wire, if desired while carrying out a dewatering operation. The removal of the fiber web or fleece is accomplished directly from the filter cylinder on to a felt web.

Abstract: A twin-wire papermaking machine contains a region having two wires guided in mutual contact with one another and at which there is located at least one stock infeed device. The stock infeed device possesses the form of a box or cabinet member having an open side along which move both of the wires. Within the stock infeed device there is located a fibrous stock suspension suitable for the fabrication of paper and which is at an excess pressure in relation to the atmosphere. At the side of the wires facing away from the stock infeed device there can be arranged a suction device.

Abstract: A twin-wire papermaking machine contains a headbox for forming a first fiber ply which is essentially downwardly dewatered at a section of a first wire. At the end of this wire section, forwardly or upstream of the inbound or on-running location of a second wire there is arranged a second headbox for forming a second fiber ply which is essentially upwardly dewatered along a subsequently arranged common path of both wires. The common path advantageously extends over an essentially water impervious, convex domed contact surface of a slide shoe and/or a jacket surface of a guide cylinder or roll. During operation, the second fiber ply is deposited upon the already extensively dewatered first fiber ply and upon passage through the common path of both wires this second fiber ply is dewatered upwardly away from the first fiber ply.

Abstract: A double sieve or twin-wire papermaking machine possesses a substantially planar section of a lower band which is equipped with a headbox. Furthermore, it contains a shoe containing a domed surface and a dewatering cylinder. Arranged after the dewatering cylinder is a deflection roll which is located at the side of both bands, typically in the form of sieves, wires or filters, which face away from the dewatering cylinder. The shoe and the dewatering cylinder are located either within the lower band or within the upper band. The first deflection roll can have arranged thereafter a second deflection roll which is located at the same side of the lower band as the dewatering cylinder.

Abstract: A headbox arrangement for a papermaking machine contains a plurality of headboxes forming a group, these headboxes being arranged either essentially in parallelism with regard to one another or in fan-like or spread apart configuration. Between each two neighboring headboxes there is located a flexible divider, particularly in the form of a foil member, which extends past the outlet gap or slice of the headboxes.

Abstract: A headbox contains a rigid lower lip which is directed towards a dewatering surface, a wire or the like, guided over a rotating cylinder or roll, and a rigid upper lip having a rigid lip portion which, in conjunction with a portion or section of the dewatering surface neighboring the lower lip downstream with respect to the flow of the stock suspension, delimits a sheet forming chamber or space. The lip portion is provided at the region of the sheet forming chamber with step or groove-like depressions or recesses extending transversely with respect to the direction of flow of the stock or fiber suspension. These recesses serve to form recirculation turbulence which supports the marginal flow of the stock suspension.

Abstract: A pulp feed for a papermaking machine, comprising a substantially slot-like guide channel having at least two step-like widened portions. Before and after each widened portion there is provided a linear channel section, and between the widened portions there is arranged a tapered section or portion. The slot widths before both of the widened portions can be of the same magnitude and conjointly adjustable by means of a translationally movable element. The slot-like guide channel has arranged forwardly thereof a perforated plate and a mixing chamber merging thereat. Also a pulp feed channel having an adjustable lip and merging at the guide channel can possess step-shaped widened portions.