Abstract:
A fiber-web machine dryer section has a drying group with single-wire draw. A drying wire (F) presses the web (W) on a drying cylinder (10) against heated cylinder surfaces, and the web (W) remains at the side of the outside curve of reversing cylinders (11) situated between drying cylinders (10). For enhancing runnability of the web (W), a runnability component (20) is in a pocket space (T) confined by two adjacent drying cylinders (10) and a reversing cylinder (11) situated between them and by the drying wire (F). The web (W) passes from the drying cylinder (10) to the reversing cylinder (11) as a short transfer of 80-400 mm, where a negative pressure effect produced by the runnability component (20) is applied and confined by seals of the runnability component (20) against the surfaces of the drying cylinder (10) and reversing cylinder (11).
Abstract:
The invention relates to a sealing arrangement (7) against a moving fabric (4b) in a paper machine or the like. The sealing arrangement includes a stiff sealing element (9) placed on the fabric's (4b) side on the entire width in connection with a paper sheet (4a) supported by the fabric (4b). The sealing element has been arranged on a support so that the location of the sealing element with respect to the fabric (4b) can be adjusted nearer to or, correspondingly, further from the fabric. As a sealing element there is at least a single-chambered labyrinth sealing (19).
Abstract:
A method of blowing drying gas against a paper web, and an impingement dryer of a paper machine. Drying gas is blown with an impingement dryer comprising several profiling chambers in the cross-direction of a paper machine, the cross-profile of the paper web being controlled with the drying gas blown from the profiling chambers. Each profiling chamber blows drying gas to its own effect range. The impingement dryer further comprises a return air chamber and return air ducts such that drying gas blown against the paper web from the profiling chambers is returned into the return air chamber through the return air ducts in such a way that some of the effect of the drying gas blown from the profiling chamber is at least partly prevented from reaching the effective area of the adjacent profiling chamber.
Abstract:
A method in the process of manufacturing and/or finishing a fiber web (11), in which method the Continuous and moving web (11), and/or a moving device (16, 17) related to the processing of the web (11), is monitored by one or more thermal cameras (10) of the infrared range or a corresponding detector/detectors for the purpose of controlling the quality or condition. A substantially continuous two-dimensional thermal image or continuous thermal chart (20) of an object (11, 16, 17) being monitored and in a propagating and/or rotating movement is formed by said detector/detectors in a time-resolved manner and in synchronization with the movement of the object (11, 16, 17) in the direction of the movement. To determine the properties of the object (11, 16, 17) and/or to detect defects in the object from the continuous thermal chart (20), local deviations and/or discontinuities (21, 22) in the temperature, particularly in the direction of movement are detected, and the cause of said deviations and/or discontinuities (21, 22) is identified on the basis of the periodicity of said phenomena in the direction of movement.
Abstract:
The invention concerns a dryer section, comprising at least one dryer group (R) that makes use of single-wire draw and/or twin-wire draw and at least one suction roll (10) with which the web (W) to be dried is in direct contact. The surface construction of the suction roll (10) is of a fine structure so that the web (W) can be passed to run over the suction roll (10) in direct contact with the roll so that the web (W) is not damaged.
Abstract:
A fiber-web machine dryer section has a drying group with single-wire draw so the drying wire (F) presses the web (W) against heated cylinder surfaces with the web (W) at the side of the outside curve of reversing cylinders (11) situated between drying cylinders (10, 12). A pocket space (T) is formed between two adjacent drying cylinders (10) and a reversing cylinder (11) situated between them, and the drying wire (F). A negative pressure component (20) placed in the pocket space (T) creates a pressure difference over the drying wire (F) and the web (W) for attaching the web (W) to the drying wire (F) so the cross-direction shrinkage of the web (W) is controllable. The wire tension (F) is maintained at a level help control cross-direction shrinkage of the web. The pocket space (T) is sealed by sealing members (25, 26) to maintain negative pressure in the pocket space.
Abstract:
A fiber-web machine dryer section has a drying group with single-wire draw so the drying wire (F) presses the web (W) against heated cylinder surfaces with the web (W) at the side of the outside curve of reversing cylinders (11) situated between drying cylinders (10, 12). A pocket space (T) is formed between two adjacent drying cylinders (10) and a reversing cylinder (11) situated between them, and the drying wire (F). A negative pressure component (20) placed in the pocket space (T) creates a pressure difference over the drying wire (F) and the web (W) for attaching the web (W) to the drying wire (F) so the cross-direction shrinkage of the web (W) is controllable. The wire tension (F) is maintained at a level help control cross-direction shrinkage of the web. The pocket space (T) is sealed by sealing members (25, 26) to maintain negative pressure in the pocket space.
Abstract:
An apparatus for a dryer section of a paper or board machine has a drying group (R) and an impingement drying unit (10) which is placed above and/or below a row (DSR) of drying cylinders (3). A drying fabric (1) supported paper or board web (2) is conducted past the impingement drying unit (10) having at least one impingement surface (IP1, IP2) the side profile of which is straight, changeably curved in its radius of curvature, in the shape of a broken line or a selectable combination of these, and that the impingement surface or a tangent line to the impingement surface or a line passing via the beginning and the end of the impingement surface or an extension of the line forms on the impingement side an angle with a horizontal plane parallel to the machine level, which angle is ≦120°, advantageously 120°–60°, most advantageously about 90°.
Abstract:
A method and equipment for tail threading in a paper machine in which tail threading is carried out in stages: the web is guided to the broke treatment at a selected dryer, a cut is formed in the web to separate a narrow tail from the rest of the web, i.e. the broke web, prior to the dryer, the edge opposite to the cut of the broke web is turned away from the cutting point to form an open draw between the tail and the broke web, the tail is guided from the selected dryer to the following section while the broke web is transferred further to the broke treatment, while travelling in a controlled manner, the tail is widened to the full width and the broke web is simultaneously reduced away.
Abstract:
A method and an apparatus for web threading in a drying section of a paper machine or the like. A leader (24) and a so called run-down strip are formed by cutting in the web coming to the drying cylinder in the drying section. An underpressure box (18) is arranged at the opening gap between the drying cylinder (14) and the drying wire, on that side of the wire which is away from the web, whereby this box can direct against the web an underpressure which is controllable in the machine's cross direction. The underpressure box creates an underpressure region (34′) between the leader and the underpressure box, the region having an underpressure p1 at the detachment point, i.e. in the area where the wire is detached from said drying cylinder (14), which underpressure is sufficient to detach the leader from said drying cylinder. A protection zone is created between the underpressure region created at the leader and the run-down strip, which protection zone has a barrier (46) in order to maintain the underpressure p1 in the underpressure region.