Abstract: A method and apparatus for filtering pulp fibers from a pulp slurry, using a combination of vacuum, hydrodynamic and hydrostatic forces in order to achieve a more effective deposition of pulp fibers onto the filter surface and enhanced flow of filtrate through the cylinder. The apparatus is in the form of an improved vacuum filtration system, in which the filtrate outlet tube is disposed along the axis of rotation of the rotary cylinder and the filtrate inlet and outlet ports of each filtrate conduct are radially offset from one another in the direction of intended rotation of the cylinder. During various phases of filter operation, vacuum forces generated by the vacuum source cooperate with either hydrodynamically or hydrostatically generated forces, which together act upon columns of filtrate in the filtrate conduits as the cylinder rotates.

Abstract: The suction roll of a dryer group is in the path of the web and of the web support belt from an upstream dryer cylinder to a downstream dryer cylinder. The suction roll has an annular roll shell having a plurality of radial holes and being free of stationary inserts at least over the predominant part of the length of the roll shell. A hollow roll journal at at least one end of the suction roll connects vacuum into the suction roll and to the radial holes. In at least some of the holes there are respective deflector pieces. Each extends a short radial distance into the inside of the roll shell over a short radial portion. The deflector piece has a continuous channel which extends radially inward through the hole toward the inside of the roll in a direction substantially parallel to the direction of extension of the hole and the radially inward portion of the channel is curved in the direction contrary to the direction of rotation of the roll shell.

Abstract: The invention concerns a suction roll (10) for a paper making machine, on which the paper web is pressed towards the outer face of the roll mantle. The suction roll (10) is divided, in the axial direction of the roll, into at least three vacuum spaced (A.sub.1, A.sub.2, A.sub.3). In the interior of the suction roll (10), there are at least two partition walls (17a, 17b), by means of which the suction space (13) is divided into separate zones of negative pressure. The lateral vacuum spaces (A.sub.1, A.sub.3) in the suction space can be subjected to a higher negative pressure than the vacuum space (a.sub.2) in the middle area of the roll, whereby the profile of negative pressure is formed such that the negative pressure increases across the width of the roll towards the lateral areas. The invention also concerns a method for producing a desired pressure profile for a suction roll.

Abstract: A hollow cylinder exhibits an internal body, which forms a sickle-shaped space by means of a partial cylindrical surface arranged eccentrically to the hollow cylinder, with a smaller radius than its internal radius. In this space there is created a vacuum on rotation of the hollow cylinder. By this means air is sucked out of the area through the boreholes of the hollow cylinder, where a web of material wraps the hollow cylinder. This leads to a firmer adherence of the web on material to the hollow cylinder.

Abstract: The invention relates to a suction roll (10) comprising a turbulence suppression element (16) located in the vicinity of the end of an external suction pipe (15). The turbulence suppression element (16) comprises at least one sheet member and is fitted relative to the end of the suction pipe (15) in such a way that turbulence in the intake air during the suction phase is substantially prevented and that a low air pressure is thus maintained at a desired, approximately constant value on the inner surface of the roll shell along the entire roll width and the quantity of suction air is also maintained at a desired, approximately constant value through the perforated sections (14) of the roll shell.

Abstract: This invention relates to a vacuum water drawing windlass for making paper and in particular to one mainly including a tubular member, a bushing fitted on each end of the tubular member, a controlling disc rigidly engaged with the other side of each bushing, a case fixedly engaged with each controlling disc, a shaft inserted into each end of the tubular member and two brackets for supporting the tubular member whereby the paper production may be increased and the quality of the paper may be improved.

Abstract: A decker comprises a tank having a thickening drum mounted rotatably therein and including a filtering shell. The inside of the drum communicates with an inlet for feeding mass, whose consistency is to be increased during the thickening process and outlets for discharging the thickened mass after the thickening process. The filtrate separated from the mass being thickened, is arranged in a flow communication from the inside of the thickening drum through the filtering shell of the drum to the bottom portion of the tank. At least one separating member is placed in the bottom portion of the tank outside the drum and forms a partition point or partition line situated transversely with regard to the direction of rotation of the drum and at a predetermined, angular distance from the horizontal plane coinciding with the axis of rotation.

Abstract: A joint dewatering zone of wires for dewatering a web to be formed in a two-wire papermachine having a first wire loop and a second wire loop, includes a first forming roll which is situated inside the second wire loop and other dewatering means which are situated after the first forming roll inside the first wire loop. The other dewatering means comprises as a combination a first suction box, a second suction box with a curved guiding surface, and a roll interposed between the suction boxes.

Abstract: The invention relates to a roll (8) for the forming section of a paper machine or the like, comprising a perforated shell (17) for removing water from a fibre suspension through holes (18) in the shell (17) into the roll (8) and being arranged to be mounted rotatably in the machine. A wire (3; 10) or the like within the forming section is arranged to be in contact with the shell (17) of the roll (8) over a part of its periphery. For improving the dewatering and the formation, the roll (8) comprises, at least substantially over the peripheral portion in contact with the wire (3; 10), bladelike means (21; 33) extending in the longitudinal direction of the roll (8). The blades are positioned within the shell (17) close to the inner surface thereof and mounted in such a manner that the shell (17) moves relative to the blades when the roll (8) rotates.

Abstract: The present invention concerns a device for generating negative pressure inside a cylindrical roll mantle of a revolving roll. The roll has a roll mantle provided with through-holes, grooves or equivalent apertures and confining a suction chamber in the interior thereof, in which a negative pressure can be generated by suctioning air out of the suction chamber. A suction flow directed towards the suction chamber thereby prevails in the holes, grooves or equivalent apertures of the roll mantle. At least one rotor blower or equivalent is attached to the roll to revolve along with the roll, with an intake side of the rotor being connected to the suction chamber of the roll. The movement of rotation of the roll thereby produces rotary movement of the rotor or equivalent, which in turn generates negative pressure in the suction chamber. Thus, in the arrangement in accordance with the present invention, external equipment of negative pressure or a separate piping system is not needed.

Abstract: A method for applying a negative pressure over a sector of an air-pervious mantle of a roll includes providing a suction chamber within the pervious roll mantle which extends over a suction sector of the roll, directing air jets away from the suction chamber at the outermost edge portions of the suction chamber, the air jets causing air currents to be ejected from the suction chamber at the outermost edge zones thereof, the air currents thereby producing air seals at the outermost edge zones of the suction chamber without the use of contact-type sealing elements and at the same time, at least partly, providing a negative pressure in the suction chamber. A suction roll includes blow nozzles for directing air jets away from the suction chamber substantially parallel to the tangent of the roll mantle proximate to the blow nozzles. The inlet sides of the blow nozzles are connected to a pressure chamber situated within the roll mantle, the pressure chamber adapted to be connected to a pressure source.

Abstract: A noise suppression device is provided for a vacuum cylinder having a conl head which is used in high speed paper converting machines and which includes a sound attenuator which is integral with the vacuum cylinder. The sound attenuator incorporates a plurality of attenuation chambers within the vacuum cylinder which are interconnected by tubes arranged in an offset manner to overlap each other in the projection. Air passages are also provided in the side of the vacuum cylinder opposite the control head to connect the last attenuation chamber to the atmosphere.

Abstract: A rotary filter drum in which the drum is a single cell having a perforated cylindrical wall and solid end walls. A hollow central shaft extends through the drum and its opposite ends extend axially from the end walls. The drum contains a plurality of relatively narrow elongated open-top pans that are equally spaced radially from and angularly about the central shaft. Each pan is defined by a bottom, spaced apart inner and outer sidewalls which extend the full length of the drum and the drum end walls. The pan walls are secured to the ends of the drum. The pans are located so the open tops face the direction of drum rotation and the entire leading edge of the outer sidewall of the pan is secured to the perforated cylindrical wall. A closed conduit connects the bottom portion of each pan to the central shaft which in turn connects to the vacuum source so the filtrate is removed from and vacuum applied to the interior of the drum solely through the central shaft but via the pans and connecting conduits.

Abstract: An improvement in the method and apparatus for fabricating asbestos-cement boards, wherein a felt band coated with fiber fleece is fed to a pair of press rollers in nip relationship and wherein the coating of the felt band with fiber fleece is effected by wet deposition on the felt band and by suction from the side opposite same.The fiber fleece obtained by wet deposition on the felt band following the deposition is condensed and dehydrated by a system consisting of a sieve cylinder and of an associated suction roller operating in nip relationship.

Abstract: A paper-machine press section having structure for transferring a web away from the press section toward the drying section of the machine. The press section includes a press roll with which a transfer structure cooperates for transferring a web from this press roll away from the latter and toward the drying section. This transfer structure includes at least a transfer suction roll having an outer shell formed with perforations through which suction is transmitted to a web. A suction chamber communicates with these perforations while between the suction chamber and the outer shell which has the perforations there is a sealing structure which is capable of providing between the perforated shell and the suction chamber a seal which does not require the use of seal water.