摘要:
A method for producing surface-treated paper, in particular of fine paper, and a dry end of a paper machine that makes use of the method. A paper web that has been dewatered by pressing is dried in the forward dryer section, in which drying energy is applied to the paper web over the entire length of the forward dryer section asymmetrically in the z-direction from the side of the bottom face of the web. This step is carried out by a number of successive groups with single-wire draw that are open downward. In this manner, shrinkage of the web both in the machine direction and in the cross direction is reduced or at least partially prevented, which shrinkage tends to take place when the dry solids content becomes higher. Paper broke is removed from underneath the drying groups that are open downward substantially by the force of gravity onto the broke conveyor placed underneath. The paper web which has a tendency of curling because of the asymmetric forward-drying is passed to the finishing section where it is finished while it is moistened and/or worked plastically so that the tendencies of curling that arose in the web in the forward drying stage are substantially reduced.
摘要:
A method for producing surface-treated paper, in particular of fine paper, and a dry end of a paper machine that makes use of the method. A paper web that has been dewatered by pressing is dried in the forward dryer section, in which drying energy is applied to the paper web over the entire length of the forward dryer section asymmetrically in the z-direction from the side of the bottom face of the web. This step is carried out by a number of successive groups with single-wire draw that are open downward. In this manner, shrinkage of the web both in the machine direction and in the cross direction is reduced or at least partially prevented, which shrinkage tends to take place when the dry solids content becomes higher. Paper broke is removed from underneath the drying groups that are open downward substantially by the force of gravity onto the broke conveyor placed underneath. The paper web which has a tendency of curling because of the asymmetric forward-drying is passed to the finishing section where it is finished while it is moistened and/or worked plastically so that the tendencies of curling that arose in the web in the forward drying stage are substantially reduced.
摘要:
A method and device for enhancing the run of a web in a paper machine in which water is removed from the web by pressing the web in at least one press nip and after pressing, the web is dried in at least one dryer group applying impingement drying. The web is guided along a substantially linear path or by using a large curve radius in the dryer group applying impingement drying. In the drying stage, after the impingement drying, the web is dried in at least one dryer group having normal single-wire draw. The web is passed from the pressing stage to the drying stage as a closed draw and more particularly, from the pressing stage to the area with single-wire draw in the drying stage so that the web is constantly supported against at least one support face.
摘要:
A device for threading a paper web from a dryer section to a finishing device situated after the dryer section in the running direction of the web including a rope threading arrangement. A leader strip is separated from the edge of the paper web in the dryer section and the leader strip is directed between a pair of ropes included in the rope threading arrangement. The leader strip is carried to the finishing device on support of the ropes. To effect the transfer of the leader strip from the drying wire to the rope, at the inlet side of the last drying cylinder in the dryer section, a rope gap is formed out of the ropes and the leader strip, which is supported by the drying wire thereat, is transferred by an air blowing into the rope gap. The leader strip is passed by the ropes over the last drying cylinder to the finishing device.
摘要:
A method and device for enhancing the run of a web in a paper machine in which water is removed from the web by pressing the web in at least one press nip and after pressing, the web is dried in at least one dryer group applying impingement drying. The web is guided along a substantially linear path or by using a large curve radius in the dryer group applying impingement drying. In the drying stage, after the impingement drying, the web is dried in at least one dryer group having normal single-wire draw. The web is passed from the pressing stage to the drying stage as a closed draw and more particularly, from the pressing stage to the area with single-wire draw in the drying stage so that the web is constantly supported against at least one support face.
摘要:
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.
摘要:
A multi-cylinder dryer for a paper machine having several drying groups situated one after the other, in which drying cylinders are situated one above the other in stacks, preferably in vertical stacks. In subsequent groups, a web is passed from one drying cylinder onto a next drying cylinder by way of a single-wire draw, so that the drying cylinders in the single-wire draw groups are situated outside the loops of their respective drying a wires. The web is passed as a supported draw from one single-wire group to a subsequent single-wire group by using at least two transfer-suction rolls. A first one of the transfer-suction rolls is situated inside a loop of a drying wire of the preceding single-wire draw group. The second or final transfer-suction roll is situated proximate to the first suction roll and inside a loop of a drying wire of the latter or subsequent single-wire draw group, proximate to a first drying cylinder in this subsequent group. Transfer of the web from one wire group to the next wire group takes place with support by a drying wire substantially all the time. At that location, the web is subjected to a difference in pressure that maintains the web in contact with a drying wire, generally a negative pressure being effective from the drying-wire side.
摘要:
Method and apparatus for guiding and directing an end conduction strip of a web from a smooth-surfaced roll, such as a paper web in a press. The end conduction strip is detached from the smooth surface of the roll and further guided by utilizing a guide plate and air blowing actions. An air jet having sufficiently great impulse is directed against the end conduction strip on the roll surface. The end conduction strip is cut with the aid of this air jet and a leading edge thereof is detached by this air jet from the roll surface. The detached end conduction strip is further guided and conveyed forwardly by a transfer blowing action. This transfer blowing action is directed along the guide plate. An under-pressure field is produced in conjunction with the guide plate, by effect of the blowing action. The effect of this under-pressure field causes the end conduction strip to be further guided in a direction determined by the guide plate.
摘要:
The present invention relates to a method and device in the draw of a paper web for reduction and equalization of transverse shrinkage of the paper web in the drying section of a paper machine. The lateral areas of the wire running in conjunction with the paper web are provided with a coating adhesion means, whereby, by means of the coating adhesion means, at the drying stage an adhesion force is produced between the lateral areas of the wire and of the paper to prevent transverse shrinkage of the paper web.
摘要:
A method in a drying group or groups provided with a single-wire draw in a multi-cylinder dryer of a paper machine in the draw of a web. The multi-cylinder dryer comprises drying cylinders heated by means of steam or equivalent, with the web being pressed by a drying wire against the cylinder faces of these drying cylinders. The multi-cylinder dryer has leading or lower cylinders on which the web runs outside the drying wire which is, for example, a felt. The leading cylinders or rolls are provided with holes passing through a mantle of the leading cylinders or rolls, these holes being fitted to open into an inner space of negative pressure within the leading cylinder or roll and to open, at an opposite end, into grooves provided on a mantle face of the rolls. The negative pressure inside the roll is arranged to be transmitted to the grooves provided on the outer face of the roll mantle, so that an adhesion force is applied to the web through the grooves. In the method, a negative pressure is applied to the entire inside mantle face of the roll, and free flow of air is permitted through the holes from an area above the cylinder and into the interior space within the cylinder. The present invention further concerns a device for use in the single-wire draw of the multi-cylinder dryer of the paper machine, and also to a paper-machine cylinder itself.