摘要:
Blistering of a wet paper web upon a yankee dryer drum is controlled by directing compressed dry air toward the wet paper web in the space between a pressure roll external of the yankee dryer hood and the entry opening between the dryer hood and the yankee dryer drum. The flow of compressed air is controlled so that air flow can be modified across the full width of the wet paper web.
摘要:
The dry end of a paper machine comprises a first dryer group with top drying cylinders, with a first drying wire and with bottom deflection suction rolls. Adjacent this, there is a second dryer group with bottom drying cylinders, with a second drying screen and with top deflection suction rolls. In this way, both sides of the web to be dried come, in succession, into direct contact with the drying cylinders. At the place where the web changes from the first drying wire to the second drying wire, there is a transfer suction roll which lies within the loop of the second support belt. The web travels there from the last cylinder of the first dryer group over an at least approximately straight travel path to the transfer suction roll and thus onto the second support belt.
摘要:
A blow device for a dryer section of a paper machine in which an air blowing is produced to support the paper web or equivalent. The device includes structure for defining an interior air space into which the air to be blown is passed through a duct communicating therewith and nozzle openings through which the air is blown to support the paper web or equivalent. The device also includes sets of equalizing plates through which the air is passed out of the air space into separate chamber spaces from which the air is passed into the nozzle openings.
摘要:
A dryer section of a paper machine including cylinder groups provided with single-wire draw having smooth-faced heated drying cylinders against which a web to be dried enters into direct contact, and reversing rolls. The groups with single-wire draw have a drying wire which is guided in a loop by guide rolls as well as by the drying cylinders and the reversing rolls so that the drying cylinders are placed outside the wire loop, and the reversing rolls are situated in gaps between the drying cylinders inside the drying-wire loop. In order to optimize the drying capacity calculated per unit of length of the dryer section in the machine direction, as the drying makes progress, a different ratio of the drying cylinder diameter to the reversing roll diameter is employed, so that, in the first group or groups in the initial end of the dryer section, the ratio is higher than the corresponding ratio in the groups in the middle area of the dryer section. In the group or groups in the final end of the dryer section, a diameter ratio is used that is higher than the ratio in the middle area of the dryer section.
摘要:
The multi-cylinder dryer of a papermachine includes a first tier of cylinders, where the web supported by a first dryer wire travels on the cylinders of the first tier of cylinders, as well as a second tier of cylinders, where the web supported by a second dryer wire travels on the cylinders of the second tier of cylinders. The first dryer wire travels from a cylinder of the first tier of cylinders to a first guide roll and delivers the web lying on its side facing the cylinder of the first tier onto the second dryer wire and, after having wound onto a second wire guide roll, again takes up, on its surface facing the following cylinder of the first tier, the web from the second dryer wire traveling through the second tier of cylinders. A section extending between the dryer cylinder and the first wire guide roll is provided on the web-free side of the wire with a nozzle for blowing air in the traveling direction of the wire into a gap between the wire and the first wire guide roll for producing a plenum zone facilitating the release of the web.
摘要:
A suction roll (1), in particular for a paper web dryer, comprising a perforated roll jacket (2), with at least one non-rotatable hollow shaft (3) which communicates with the interior of the suction roll via openings (7, 7') and at least one closing member (9) displaceable in the axial direction for separating off at least one peripheral region of the suction roll. The at least one, in particular disc-shaped dividing wall (5) is located in the suction roll interior and has at least one, preferably central opening (22). It can be of benefit when the dividing wall (5) corotates with the roll and/or when the at least one closing member (9) has the form of a hollow cylinder. Further, if the non-rotatable hollow shaft (3) is designed to be axially displaceable, it can be used to control the size of the opening (22) in the dividing wall (5).
摘要:
A dryer section of a machine for manufacturing fiber webs, which includes a plurality of heatable drying cylinders arranged to form at least a first dryer group and a second dryer group, and arranged in horizontal cylinder rows, and including a plurality of suction rolls each being disposed between two adjacent cylinders. The cylinders of the first group have axes disposed in a first plane I, the suction rolls of the first group have axes disposed in a second plane II, the cylinders of the second group have axes disposed in a third plane III, and the suction rolls of the second group have axes disposed in a fourth plane IV. In accordance with different embodiments planes I and II may be coplanar, planes II and III may be coplanar; planes I and III may be disposed between planes II and IV; and the axes of the first drying cylinders and its associated suction roll of the second group may be disposed below the axes of the other drying cylinders and suction rolls of the second group.
摘要:
A method for use in web drying apparatus, such as a drying section of a coating or paper machine which includes drying cylinders against the outer mantles of which a web to be dried is pressed in direct contact, and wherein the web is carried from one drying cylinder to the next supported on a wire which passes from a drying cylinder over an intermediate leading cyclinder where the web is carried on the outer side of the wire out of direct contact with an outer mantle of the leading cylinder, and then to the next drying cylinder, comprises the steps of maintaining a negative pressure in a pocket space defined between a pair of successive drying cylinders and the web-supporting wire for suctioning the web into contact with the wire as it runs from one drying cylinder to the intermediate leading cylinder and from the intermediate leading cylinder to the next drying cylinder, and providing the leading cylinder with a perforated outer mantle and maintaining a negative pressure within the interior of the outer mantle, to thereby render it a suction cylinder for suctioning the web into contact with the wire as the wire travels over the suction cylinder. Apparatus for use in the method includes a pocket chamber for enclosing the pocket and apparatus for maintaining negative pressures in the enclosed pocket space and interior of the leading cylinder.
摘要:
A vacuum roll transfer apparatus is disclosed for drying a web extending through a single tier dryer section of a paper machine. The apparatus includes a rotatable perforate shell having a first and a second end. A stationary duct is disposed within and along the length of the shell between the ends of the shell. The duct is connected to a source of partial vacuum and the shell defines a plurality of holes along the length thereof such that in use of the apparatus, when the duct is connected to the source of partial vacuum, a partial vacuum is generated within a chamber defined between the shell and the duct. A flow restricting arrangement is disposed within the duct for generating a greater vacuum level adjacent to at least one of the ends of the shell for facilitating threading of a tail of the web.
摘要:
A papermachine drying apparatus is disclosed for drying a first and a second side of the web. The apparatus includes a first single tier drying section for drying only the first side of the web. The first drying section includes a first plurality of dryer cylinders for drying the first side of the web, and a first plurality of vacuum rolls disposed in close proximity between adjacent dryer cylinders of the first plurality of dryer cylinders. A second single tier drying section for drying only the second side of the web in which the drying section includes a second plurality of dryer cylinders for drying the second side of the web, such cylinders being disposed immediately downstream relative to the first drying section. A second plurality of vacuum rolls are arranged such that each vacuum roll is disposed in close proximity between adjacent dryer cylinders of the second plurality of dryer cylinders. At least one of the vacuum rolls of the first and the second drying sections have a smaller diameter than the diameter of any of the dryer cylinders of the first and second drying sections, and the second drying section is a displaced downstream mirror image of the first drying section.