摘要:
A gravure paper and a method of manufacturing gravure paper having a maximal roughness depth of approximately 1.40 &mgr;m. The method utilizes a paper machine including a forming system, a first press section, and a drying section, and includes producing a stock suspension including a stock having a freeness of greater than or equal to approximately 50 ml CSF, forming an unfinished fibrous material web from the stock suspension, and applying at least one of a pigment and a filler slurry to the unfinished fibrous material web between a beginning of the forming system and a position at which the dry matter content of the unfinished fibrous material web is approximately ≦90%.
摘要:
Process and device for acting on one of a still-wet and moist material web with one of a fluid and pasty coating medium in the manufacturing process. The process includes producing the material web in a wet section of a web producing machine, applying, in at least one coating point, a coating medium to at least one surface of the material web while the material web is in the wet section, and applying at least one of steam and water in the region of the at least one coating point. The device includes at least one endless, water-permeable belt, at least one coating device being adapted for one of direct and indirect application of a fluid or pasty coating medium onto at least one side of a still-wet material web, and at least one applicator device, positioned in a region in which the coating medium contacts at least one of the material web and at least one belt, being adapted to condition the at least one of the material web and the at least one belt with at least one of steam and water.
摘要:
A papermaking machine and a method for applying an application medium to a moving web of material in a papermaking machine. The papermaking machine has a wet end section, a press section, a drying section and an applying device for applying a medium to a moving web of material. The wet end section includes a twin wire area having a first wire and a second wire wherein the web of material is formed and positioned between the two wires and separated from the two wires before moving to the press section. At least one wet end section applying device is positioned on one side of at least one of the first wire or the second wire within the twin wire area and facing away from the web of material positioned on the wires. The press section of the papermaking machine has a first press element and at least one press section applying device facing directly toward the web of material. The method includes forming a web of material in a twin wire area of a wet end section of the papermaking machine, applying at least one first medium with at least one wet end section applying device to at least one side of the web of material within the twin wire area of the wet end section of the papermaking machine, moving the formed web of material to the press section of the papermaking machine, and applying at least one second medium to the formed web of material with at least one press section applying device after the web of material passes a first press element of a press section of the papermaking machine.
摘要:
Wire section, guidance device, and process of forming a web in a machine for producing a fibrous material web. The device include two revolving endless wire belts, a twin wire zone formed between the two revolving endless wire belts, and a revolving flexible support belt located in a vicinity of the twin wire zone and positioned to support at least one of the two wire belts in a support region. The flexible support belt is generally guided along an at least essentially circular cylindrical path, and the support region includes a support path having an average curvature radius that is greater than a curvature radius of the essentially circular path. The process includes supporting at least one of the two endless wire belts with the flexible support belt in a support region, rotating the flexible support belt along a generally circular path, and deflecting the support belt from the generally circular path in the support region, whereby the support belt in the support regions travels along a support path. An average radius of curvature of the flexible support belt in the support path is greater than an average radius of curvature of the flexible support belt in the generally circular path.
摘要:
The present invention relates to a twin wire former in a machine for the production of a fiber web, especially a paper or cardboard web from at least one fiber stock suspension, including a vertical twin wire segment having two wires running over a peripheral area of a turning element, especially a guide roll whose surface is preferably not equipped with suction and is smooth or substantially smooth; and in that at least one separation element, such as a transfer suction box is provided indirectly or immediately following the guide roll that separates the top wire from the bottom wire on which the fibrous web is supported.
摘要:
The invention relates to a twin wire former for the production of a fiber web specifically a paper, cardboard or tissue web, from a fiber suspension. The invention is characterized in that the rotating forming roll has an open volume and is a non-suction type; the rotating forming roll has a forming roll diameter of less than 1,400 mm; the rotating forming roll has a forming roll angle of wrap of less than 70°; a forming suction box is located immediately downstream from the rotating forming roll as viewed in direction of wire travel; and in the area of the wedge-shaped inlet nip, the fiber stock suspension has a stock density of between 0.4% and 2.0%, preferably between 0.6% and 1.5%. These characteristics result in an improved forming quality and web quality.
摘要:
The invention relates to a method for optimizing the energy balance of a forming section in a machine for producing fibrous webs, in which a fiber suspension, which is fed to the forming section by way of a material ramp after the immobility point is reached, is passed through at least two dewatering units within a compression zone and to a subsequent functional unit. The invention is characterized in that a setpoint value for a target dryness to be set is predefined based on the existing dewatering elements as a function of a theoretical maximum achievable dryness under plant conditions in the area of the transition zone, said setpoint being selected such that it is less than the theoretical maximum achievable dryness but is equal to or greater than a required minimum dryness in the area of the transition zone, and that the target dryness is controlled by lowering the inlet dryness at one of the last dewatering units disposed in the direction of passage of the fiber suspension within the compression zone.
摘要:
The present invention relates to a method and a corresponding plant for producing a fibrous web, in particular a paper web, paperboard web or tissue web. The formation of the fibrous web is defined online as a controlled variable and is held at a preselectable set-point level by way of an automatic formation control system.
摘要:
A wire part of a machine for the production of continuous fibrous material webs, especially a papermaking machine, includes two continuous wire belts which together form a twin-wire zone. At least one supporting element having a supporting surface is disposed in the region of the twin-wire zone. At least a part of the supporting surface provides a supporting region which supports a first wire belt on its inner surface and a second wire belt on its outer surface. At least one formation box is provided and is disposed in the supporting region. The formation box is designed in such a way that, in the region of the inner surface of the second wire belt in the formation box, pressure values can be adjusted from a reduced pressure to an excess pressure acting on the inner surface of the second wire belt. The formation box extends in the direction of movement of the wire part over at least a part of the supporting region.
摘要:
A headbox includes a feed device feeding the fibrous material suspension, a nozzle, and a turbulence-generating device. The fibrous material suspension is guided in the turbulence-generating device in sub-flows through turbulence-generating channels. Within the individual turbulence-generating channel of the turbulence-generating device, at least one region forming a fluidization region is provided, in which a pressure loss can be generated in the sub-flow of the fibrous material suspension guided through said region. The nozzle and the turbulence-generating device are designed and dimensioned such that they are suitable for setting a dwell time of ≦200 ms of the fibrous material suspension flowing through the same from a final fluidization region of an individual turbulence-generating channel before inlet into the nozzle as far as the outlet gap of the nozzle, and a pressure loss of ≧50 mbar in the final fluidization region upstream of the inlet into the nozzle.