Valmet Oy

Valmet Paper Machinery Inc.

Erkki Koski

Martti Koponen

Jouni Koskimies

Olli Tapio

Martti Pullinen

A method is provided for the removal of water from a web by hot-pressing while the web is in direct contact with a heated cylinder face. The web is passed, while being supported by a press fabric, through at least two separate press stages. The web is first passed into direct contact with the heated cylinder face and into an extended-nip press stage. At the beginning the extended-nip press stage, a press-glide belt is passed into contact with the press fabric, the press-glide belt is pressed by means of a press member in the extended-nip stage against the heated cylinder face. This press-glide belt is separated from the fabric and the web is passed to the next stage where the web is pressed against a cylinder face only by means of the tension of the press fabric. After this latter stage, the web is passed to an intensive roll-nip pressing stage, through a roll-nip which is formed between the hot cylinder and a hollow-faced press roll. In this stage, water is removed from the web into the press fabric and into the hollow face of the press roll. The press fabric is separated from the web, which is then detached from the face of the hot cylinder.

Hot-pressing method

A device is provided for the removal of water from a web by hot-pressing while the web is in direct contact with a heated cylinder face. The web is passed, while being supported by a press fabric, through at least two separate press stages. The web is first passed into direct contact with the heated cylinder face and into an extended-nip press stage. At the beginning of the extended-nip press stage, a press-glide belt is passed into contact with the press fabric. The press-glide belt is pressed by means of a press member in the extended-nip stage against the heated cylinder face. This press-glide belt is separated from the fabric and the web is passed to the next stage where the web is pressed against a cylinder face only by means of the tension of the press fabric. After this latter stage, the web is passed to an intensive roll-nip pressing stage, through a roll-nip which is formed between the hot cylinder and a hollow-faced press roll. In this stage, water is removed from the web into the press fabric and into the hollow face of the press roll. The press fabric is separated from the web, which is then detached from the face of the hot cylinder.

Hot-pressing and drying device

A twin-wire former for a paper machine having a lower wire and an upper wire. The former has a twin-wire forming zone which has forming members and forming zones situated in a specific sequence as follows. A downwardly curved forming zone is confined to a sector of a large-diameter forming roll mounted on a frame of a lower wire unit, the magnitude of this sector being within the range of &lt;90.degree.. A second forming roll then follows which is preferably provided with a hollow face and onto which the wires arrive from the first forming roll. The twin-wire forming zone is curved within a certain sector of less than 90.degree. on the second forming roll so as to become horizontal. A forming shoe is provided with a ribbed deck and fitted after the second forming roll inside the lower wire loop, this forming shoe having a relatively large curve radius after which the twin-wire forming zone ends and the web is arranged to follow along with the lower wire.

Twin wire former for a paper machine

A web-forming method is applied in a paper machine. The web-forming section which includes a lower wire loop having an initial single-wire run and dewatering zone in which the web is dewatered through and an upper wire loop having a joint run with a subsequent run of the lower wire to form a two-wire dewatering zone within which dewatering takes place substantially through the upper wire. A first open faced forming roll is situated within the upper wire loop so that the two-wire dewatering progress begins upwardly in the region of the first forming roll. A forming shoe within the lower wire loop has a curved deck whose center of curvature is situated on the side of the lower wire loop and further guides the joint run of the upper and lower wires in the two-wire dewatering zone. A second forming roll situated within the lower wire loop after the forming shoe guides the joint run of the upper and lower wires over a downwardly curved sector thereof. According to the method, initial dewatering occurs in the single-wire dewatering zone through the lower wire. In the two-wire dewatering zone, within the range of the first and second forming rolls and the forming shoe situated therebetween, dewatering occurs first within the sector of the first open forming roll in two directions through both the upper and lower wires and primarily through the upper wire. The web is thus substantially dewatered whereupon within the region of the forming shoe, further dewatering takes place primarily upwardly through the upper wire and thereupon the dewatering pressure is further increased within the range of the second forming roll while dewatering continues to take place substantially through the upper wire.

Web-forming method in a paper machine

A web-forming section and method in a paper machine. The web-forming section includes a lower wire loop having an initial lower wire run constituting an initial single-wire dewatering zone of the web-forming section in which the web is dewatered through the lower wire, and an upper wire loop having a joint run with a subsequent run of the lower wire to form a two-wire dewatering zone of the web-forming section within which dewatering takes place substantially through the upper wire. A first open faced forming roll is situated within the upper wire loop so that the two-wire dewatering zone begins and curves upwardly in the region of the first forming roll. A forming shoe within the lower wire loop has a curved deck whose center of curvature is situated on the side of the lower wire loop and further guides the joint run of the upper and lower wires in the two-wire dewatering zone. A second forming roll situated within the lower wire loop after the forming shoe guides the joint run of the upper and lower wires over a downwardly curved sector thereof. According to the method, initial dewatering occurs in the single-wire dewatering zone through the lower wire. In the two-wire dewatering zone, within the range of the first and second forming rolls and the forming shoe situated therebetween, dewatering occurs first within the sector of the first open forming roll in two directions through both the upper and lower wires and primarily through the upper wire. The web is thus substantially dewatered whereupon within the region of the forming shoe, further dewatering takes place primarily upwardly through the upper wire and thereupon the dewatering pressure is further increased within the range of the second forming roll while dewatering continues to take place substantially through the upper wire.

Web-forming section in a paper machine

Size press

A supporting beam for a paper machine foil or the like is constituted by a horizontal box-type beam, the height of which is in the range of about 1.3 to 2.5 times the breadth of the beam and the side walls of which extend substantially perpendicularly to the run of the paper machine wire which passes over the foil supported by the beam. According to the invention, to reduce the vibrations of the supporting beam, stiffener members are disposed in the rearward upper and forward lower quadrants of the interior of the beam extending parallel to the longitudinal axis thereof. The stiffener members function to incline the principal axes of inertia of the beam at a small positive angle to the vertical and horizontal planes passing through the center of gravity of the beam relative to the direction of run of the paper machine wire. The stiffener members are situated on the inwardly facing surfaces of the vertical side walls of the beam and preferably extend substantially over the entire length of the beam. The stiffener member situated in the rearward upper quadrant is located proximate to the top side wall of the beam and the stiffener member situated in the forward lower quadrant is located close to the lower corner of the beam.

Supporting beam for a foil in a paper machine

A headbox for a paper machine includes a distributor beam part communicating with a distribution part and a turbulence part followed by a slice part. The turbulence part is constituted by a turbulence generator member in which a plurality of flow bores are formed, the outlet mouths of the flow bores opening into flow slots formed in the turbulence generator and wherein a central plane of each flow slot forms an angle with the axes of the flow bores, the magnitude of the angle being in the range of about 5.degree. to 45.degree.. The headbox may also include an equalizing chamber in which a pulp suspension is adapted to flow in an upwardly slanted flow direction and in this case the axes of the flow bores form a declining angle with the flow direction in the equalizing chamber, which declining angle is in the range of about 5.degree. to 15.degree..

Headbox for a paper machine

A multi-nip press portion or section of a paper or cardboard machine wherein a web is detached from a forming wire by a pick-up roller and transferred onto a first fabric which carries the web into the first nip and wherein the press section includes at least two water-removing press nips which include a common smooth-surface central roller. The central roller has a downwardly facing open sector with which a scraper is associated for passing the web in the case of a break to a pulper or the like. The first nip, which can constitute a press nip and/or a transfer nip is formed by a counter-roller situated in nip-defining relationship with the pick-up roller. A second fabric passes through the first nip over the counter-roller and carries the web on its upper face from the first nip to a second double-fabric nip through which the second fabric, constituting a lower fabric, and a third fabric, constituting an upper fabric pass. The third fabric has a substantially vertical run on which the web is carried from the second nip to a third nip defined by a press roller and the smooth-surfaced central roller. After passing through the third nip, the web separates from the third fabric and follows the surface of the central roller to either a following nip or nips or to a web detachment point.

Multi-nip press portion of a paper or cardboard machine

A press section in a paper machine includes a first double felted press nip defined by first and second rolls through which first upper and second lower felt fabrics pass and at least two single felted press nips defined with a plain surface roll, the first felt fabric passing through a first one of the single felted press nips. The press section includes only non-suction rolls, the first and second rolls defining the first double felted press nip each having a solid shell and recessed surface. The first felt fabric supports the web leaving the wire section and is guided over a first sector of the first recessed surface roll wherein the direction thereof is changed so as to be directed generally upwardly prior to the first double felted press nip. The second lower felt fabric which passes through the first double felted press nip is guided over a second sector of the first recessed surface roll which comprises at least a substantial portion of the first sector thereof to provide external support for the web. The second felt fabric is separated from the web substantially immediately after the first double felted press nip whereupon the first felt fabric and web supported thereby is conducted to and passes through the first single felted press nip, the web then detaching from the first felt fabric and adhering to the surface of the plain surface roll for subsequent passage through the second single felted press nip.

Press section in a paper machine

A size press having at least one coating nip avoids splashing of the sizing or equivalent coating agent by leading the web to be treated through said nip. Coating supply apparatus supplies coating pools at the nip entrance between a coating roller and the web entering said nip. The coating supply apparatus includes filling pieces in the nip entrance, placed in the coating pool in operating position. The filing pieces consist of permeable, porous, or perforated material and extend along the entire width of the web. The filling pieces suppress the coating pools and prevent or, at least, essentially decrease, the splashing of the coating agent.

Size press with coating pool suppressing arrangement

Calender apparatus for paper or the like adapted to be directly associated with a paper machine and to operate as an on-machine supercalender includes a plurality of hard calendering rolls arranged over one another so as to form a stack of hard rolls and a plurality of soft calendering rolls adapted to define a series of soft supercalender nips with the hard rolls. The hard and soft rolls are mounted on drivable support apparatus whereby the hard nips defined by the hard rolls can be opened and the soft supercalender nips closed in order to accomplish supercalendering operation on a web passing through the apparatus.

On-machine supercalender apparatus for paper or the like

A paper machine drying section has a pair of staggered rows of rotary dryer cylinders which include a first group of cylinders of both rows which form an initial part of the drying section where a web is initially received from a press section. A first endless fabric which forms a closed loop is guided around the above group of cylinders in a manner situating the cylinders of one of the rows within the loop to form inside cylinders therefrom and the cylinders of the other of the rows outside of the loop to form outside cylinders therefrom, this first endless fabric transporting a web which is to be dried around the cylinders of the above group while situating the web between the first endless fabric and the outside cylinders and the first endless fabric itself between the inside cylinders and the web. A second endless fabric structure is pressed against the web only at the portions thereof which lap the inside cylinders for preventing the web from being displaced by centrifugal force outwardly away from the inside cylinders, a suitable speed-control being connected with the second endless fabric structure to provide for the latter a speed of travel according to which the portions of the second endless fabric structure which lap the inside cylinders have an angular velocity substantially equal to the angular velocity of the inside cylinders.

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Jyvaskyla, Finland

Erkki Koski