摘要:
The suction roll, especially for a paper web drier, comprises a perforated roll shell containing therein an internal chamber partitioned by a wall member transversely arranged with respect to the lengthwise axis of the suction roll. A connection flow communicates the interior of the suction roll with a suction device, preferably a vacuum pump. At least one blade or vane within the suction roll at least reduces or prevents a possibly arising rotational or cyclone-like flow. Thus, the pressure differential brought about by the suction device can be completely used for creating the suction action and for fixing the paper web at the suction roll. This rotational or cyclone-like flow particularly occurs when the suction action is applied through a hollow shaft or duct.
摘要:
The apparatus for interconnecting two groups of driers of a papermaking machine serves to interconnect two successive drying sections through which successively travels a paper web which is dried by such successive drying sections. When needed or desired, such interconnection must be interrupted. For this purpose there are used additional elements which are capable of bringing about a separation of the endless drying wires associated with the respective web drying sections and, at the same time, during normal operation, that is, during the transfer of the paper web from the one to the other drying section, affording a regulatable operation capable of retaining the quality of the paper web. Thus, for this purpose there are proposed the use of adjustable rollers and also suction boxes operated under vacuum conditions.
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 drying section of a paper machine includes a plurality of individual drying groups, wherein the drying cylinders of a drying group are served by 2 respective dryer wire or felt that passes over drying cylinders of the drying group and presses a web to be dried against the surface of the drying cylinders. The invention is adapted for either single tier or double tier drying groups. At least one press roll is disposed between and separates two of the drying groups. In one embodiment, the at least one press roll forms a nip with the adjacent drying cylinder, either upstream or downstream, to define a dewatering nip through which the web passes. A dewatering belt passes over the press roll in the nip. The wire for a respective drying group is guided away from the dewatering nip so that only the web and the dewatering belt pass through the press nip. In alternate embodiments, two press rolls may be disposed between the adjacent drying groups, and the two press rolls define a press nip between them. A respective dewatering belt passes over each of the press rolls. One of those press rolls may also be in contact with and define a press nip with the adjacent drying cylinder in the adjacent drying group. An open draw free path may be defined between one of the press rolls and the adjacent drying cylinder.
摘要:
A drying section of a papermaking machine includes several drying groups with at least one drying screen each. At the end of one drying group and/or at the beginning of the next following drying group, a finishing roller is utilized. A finishing nip is formed between one of two finishing rollers and a finishing roller and a drying cylinder of an adjacent drying group. Only the paper web is conveyed through the finishing nip.
摘要:
A material web drier containing a device for controlling the gas flow of a drying medium as a function of the actual state of the wet material web which is to be dried, comprising nozzle casings or surfaces containing blow-out or discharge openings arranged in cooperating relationship with respect to the material web. The discharge openings are directed towards the material web and serve for blowing-out the drying medium onto the web. For the purpose of dosing the gas flow or stream effluxing at the nozzle casings or surfaces, there are provided opening and closing elements which free the discharge openings or partially or completely close the same, as desired, whereby it is possible to vary the impingement of the material web by the drying medium selectively at discrete locations or regions thereof, both in the lengthwise and transverse directions of such material web.
摘要:
The ledge is arranged transverse to the machine direction in a substantially flexure resistant manner and is adjustable for guiding the wires between which a web of material is formed. The ledge contains a guide surface which faces the wires and has a special contour. For improved control of the pressure changes occurring in the region of the ledge, the ledge contains a supporting member and a pressing member which contains the guide surface. A pressing device is supported at the supporting member and the pressing member can be adjusted in a direction relative to the wires as well as relative to the supporting member by using the pressing device for simultaneously elevating the pressing member and inclining the pressing member with respect to the machine direction. Advantageously the pressing device constitutes a hose which is subjected to a pressurizing medium and thereby deformable. The hose is at least partially imbedded into the supporting member such that its deformation causes movement of the pressing member. For simultaneously inclining the pressing member during such movement, a connecting member is provided between the pressing member and the supporting member. The ledge permits the adjustment of optimum pressures along a sheet forming zone whereby the sheet formation is improved.
摘要:
The separator of the machine is constructed to retain the paper web on the inner (upper) wire upon separation of the two wires. To this end, the separator positions the roll for the outer (lower) wire downstream of the point of separation of the two wires. A suction box can be used in the separator roll to assist in retaining the paper web on the inner wire (FIG. 1). The inner wire extends from the separator along a straight run which defines an angle of less than 90.degree. relative to the straight path traversed by the two wires upstream of the separator.
摘要:
Process and device for draining a fibrous pulp suspension. The process may include positioning two surfaces to converge in a downstream direction, feeding the fibrous pulp suspension between the two converging surfaces, driving at least one of the two converging surfaces to move the suspension with a relative translational velocity, and draining the fibrous pulp suspension through each of the two surfaces. The device may include two arcuate surfaces positioned to form converging surfaces. One of the two arcuate surfaces may include a drivable, pivotable, and rotatable cylinder having an outer sleeve with openings, the other of the two arcuate surfaces may include a screen positioned to be guided around at least a portion of the outer sleeve. The screen and the openings may form drains for draining the fluid pulp suspension.
摘要:
The invention relates to a method for roll cooling in paper machines with soft smoothing mechanisms. The object of the invention is to protect the soft roll from damage without having to increase the extent of edge trimming of the paper web. This is achieved in that the parts of the soft roll which respectively project beyond the width of the paper web are cooled by the application of a thin and sharply bounded water film. The corresponding devices for generating the water films are mounted in carriages which are displaceable along a transverse beam parallel to the roll.