Abstract: In order to cut a paper web, which is wound in a drum reel-up, by means of a transverse strip forming a free wedge-shaped end, which is passed around a new reeling drum (7a) driven by a surface winding drum, the invention proposes an apparatus comprising a conveying channel (15) having a longitudinal aperture (19) facing the surface winding drum (4), and extending below the web (2) up to the vicinity of a nip (27) defined by the surface winding drum (4) and the new reeling drum (7a) at a place beside the web. The conveying channel (15) is provided with means for producing gas jets (44, 45) arranged to actuate from both sides a length of strip (29a) inserted into the conveying channel (15) in such a manner as to maintain it in position therein for conveyance to the nip (27).

Abstract: A method and apparatus for forming a web having a predetermined grammage profile in its transverse direction is provided. The method includes the steps of introducing a composite flow of particulate material suspended in air into the distribution chamber of a forming head and depositing the material on the upper surface of an air permeable belt while applying suction to form a web and while the grammage profile is controlled by measuring the profile of the web downstream of the distribution chamber, comparing the measurement with predetermined set points, generating a control signal representative of any detected difference and controlling the amount of suction applied in predetermined suction sections in response to the control signal so as to provide a web having a predetermined grammage profile. An apparatus for accomplishing each of the steps of the method is also provided.

Abstract: A vat paper machine is disclosed, said machine including a cylinder-vat unit having a rotatable cylinder mold, a vat and a headbox for providing a continuous supply of stock to the vat. The vat is arranged upstream of the cylinder mold in such a manner that the wire-covered cylinder mold is brought into contact with stock in the vat to form a first web by draining water from the stock through the wire-covered surface of the mold. An outer wire is also provided which runs in a loop over a breast roll, through the vat along its bottom wall and then over and around a portion of the circumference of the cylinder mold. The portion of the bottom wall of the vat which is located between the breast roll and the cylinder mold includes a platform supporting the outer wire. The platform is provided with slit means that form one or more drainage passages which serve to form a second web on the outer wire.

Abstract: In order to achieve a sanitary paper web having high bulk, bulk softness and surface softness it is proposed according to the invention that said web contains expanded microspheres (11) of thermoplastic material in an amount of from 1 to 10% based on the weight of the dry web.

Abstract: A drum for stripping branches, bark and like so-called waste from trees or like woody plants, or for at least pre-treating the trees or like woody plants in a manner to soften or crush the branches and bark thereon, comprises a plurality of mutually co-axial drum sections (1-6). For the purpose of preventing a tree from being lifted in the drum under the action of obliquely positioned stripping bars, the drum sections are rotated alternately in clockwise and anti clockwise directions, which also prevents the tree from being rotated about its longitudinal axis. The stripping bars, which co-act with openings (22, 23, 24) through which removed waste material is released from the drum, are obliquely positioned relative to the axis of rotation (27) of the drum. The stripping bar of each drum section is obliquely positioned relative to the stripping bar of an adjacent drum section.

Abstract: A method and apparatus for delivering a multilayer stock jet to a forming surface in a papermaking machine with a multilayer headbox having a slice chamber formed by side walls and top and bottom walls terminating in lip members defining a slice opening and at least one relatively rigid stock separating partition fixed at its upstream end and attached to the side walls at points downstream of and at a distance from said upstream end and dividing the slice chamber into separate slice channels through which separate papermaking stocks are fed by separate pumps and discharged through the slice opening to the forming surface, in which ultrasound distance measuring devices are used to detect any deviation of the partition from a straight line connecting the points of its attachment to the side walls of the slice chamber and at least one of the stock feeding pumps is controlled in response to any detected deviation to reduce the deviation to a negligible value.

Abstract: A barking drum has a substantially cylindrical drum shell (1) with an essentially horizontal axis and at least one bearing ring (3) or similar device. The ring (3) surrounds an annular portion of the shell (1) and forms an interjacent gap (5). Further, the ring (3) is fixed relative to the drum shell (1) by means of a plurality of fastening means (7) fitted in the gap (5) and spaced at equal distances around the circumference of the shell. In order to produce an improved fixing of the ring (3) and the shell (1) in relation to each other, at least some of the fastening means (7) consist of an adjustable clamp that is expandable in a radial direction relative to the shell (1) and which is so constructed that any resilience is negligible, so that the ring (3) is substantially rigidly clamped onto the shell (1).

Abstract: A method and apparatus which reduces the amount of energy consumed in drying a paper web are disclosed. The reduction is accomplished by trimming the paper web while it is being conveyed on a moving fabric to divide the formed web into a trimmed web and couch trimmings respectively. Thereafter, suction is applied in the area where the pick-up of the trimmed web from the fabric is accomplished so as to deflect the portion of the felt on which the couch trimmings lie. As a result, only the trimmed web is conveyed to the drying section so that no energy is expended in drying the couch trimmings. The apparatus and method is particularly applicable to the manufacture of paper having a low grammage (basis weight) since contact between the couch trimmings and the pick-up felt is avoided.

Abstract: An apparatus is disclosed for discharging material through an elongate aperture in a substantially constant amount per unit length of said aperture. The apparatus comprises a screw discharging unit having an inlet end and including a screw housing with a casing wall and a screw rotatably mounted in the screw housing. The elongate aperture is provided in the casing wall and extends substantially parallel to the axis of rotation of said screw. The screw has a core and at least one screw blade extending around the core and having a predetermined pitch for feeding the material from said inlet end to the elongate aperture. The core and said casing wall define therebetween a space having an annular cross section area successively decreasing in the direction of feed of the screw.

Abstract: A method and apparatus for obtaining information, during operation of a headbox for a paper machine, about the size, at one measuring point at least, of a stock discharge slot which is bounded by two structural members comprising two lip members of the headbox of two partitions arranged between the lip members or one of said lip members and one of said partitions. According to the invention, for every such desired information, an ultrasonic transducer means arranged at the measuring point in the headbox and with a combined transmitter and receiver for ultrasound is arranged to transmit an ultrasonic pulse through the stock between two of said structural members within predetermined surface areas of these located in proximity to said discharge slot.

Abstract: The invention relates to a method and an apparatus for detecting and counteracting a deformation of the stock discharge gap in a paper machine headbox, which is caused by thermal expansion due to the temperature of the stock and/or the pressure of the stock. This is achieved by ultrasonic transducers located close to the slice opening which obtain measurement results relating to the distance between the roof member and the apron beam member of the headbox. At least two such transducers, one preferably located close to a side wall of the discharge gap and the other preferably located midway between the side walls, give information about a possible difference between the measurement results caused by the deformation. This difference serves as a guide for adjusting the temperature of the apron beam member and/or the roof member in such a way that the deformation is reduced in magnitude or entirely eliminated.

Abstract: A control system for controlling a multilayer headbox for a paper machine, which headbox there are three channels converging in the direction of flow and through which stock is conducted from separate inlets to discharge slots at the slice opening for discharge of layer-forming stock jets. Each channel is connected by a feed pipeline for stock supply by means of a motor-driven pump, the speeds of which are controlled by individual speed regulator units. The control system includes a first controller, which emits an output signal as a function of a possible deviation of an actual value of the pressure of the stocks inside the headbox from a setpoint for the pressure, which output signal is transmitted to all speed regulator units in order to regulate the speeds of the motors synchronously and, by means of the pumps, to alter synchronously the stock supply to the channels.

Abstract: An apparatus is disclosed for screening and separating wood chips or the like according to thickness. In the illustrated embodiment, the apparatus comprises two generally horizontal decks mounted one beneath the other, and with each deck having three screening sections disposed in a serial arrangement along its longitudinal length. Each screening section comprises an opening in the associated deck, a stationary grid composed of parallel rod elements disposed in the opening, and a movable grid which is also composed of a plurality of rod elements and which are disposed in alternating relation with the rod elements of the stationary grid. Further, the grids are arranged so that the gaps between the rod elements are parallel and of predetermined uniform separation throughout.

Abstract: In order to produce a reduction in the content of suspended matter in the surplus white water in a twin-wire machine with a curved forming zone, an outer saveall for collecting white water thrown outwardly from the curved forming zone is divided up into at least two separate saveall compartments arranged after each other in the direction of travel of the wires. The white water that is caught in the separate saveall compartments is removed as separate fractions for reuse.