摘要:
The invention concerns a method of controlling the relative flow speed of the layers in a multi-layer headbox with laminae mounted torque-free between upper and lower lips which are stationary when in operation. The invention is characterized in that a difference in speed is produced between the individual layers by causing the static pressure to change differently in the different layers.
摘要:
A nozzle of a multilayer headbox wherein the headbox includes a nozzle for distributing the stock suspension on a wire. The nozzle is subdivided by at least one machine-wide fin, the fin forming with the nozzle at least two machine-wide nozzle ducts. At least the mean value of the clearance of at least one nozzle duct diminishes steadily in the flow direction, the percentage decrease of the clearance in the fluidically essential area of the nozzle being at least twice as large as in the starting area of the nozzle. The fin has downstream end area of decreasing thickness immediately preceded by an area of increasing thickness.
摘要:
In a twin-wire former for the production of a paper web, two wire belts (11 and 12) together form a twin-wire zone which is divided into three sections (I, II and III). In the first section (I) the two wires (11, 12) travel over a curved forming shoe (16). They form there a wedge-shaped inlet slot (15) with which a headbox (10) is directly associated. In the second section (II), several resiliently supported strips (27) rest against the lower wire (11) and between each of said strips (27) a rigidly mounted strip (28) rests against the upper wire (12). In the third section (III) both wire belts (11, 12) pass over another curved forming shoe (23).
摘要:
A paper machine forming section with two twin-wire sections for forming a multilayer paper web. Each twin wire web-forming unit consisting of a headbox, two wire loops arranged to define a common wire path for molding the web being formed in sandwich-like manner and drainage elements for each of the wire loops. The common wire path of each web-forming unit has a first section including a curved suction drainage element or roll in the first lower wire loop; a second section including opposing drainage ledges, wherein the drainage ledges are stationary on the upper side and the drainage ledges are developed resiliently pressable on the bottom side; the drainage ledges of the upper and lower sides are arranged staggered with respect to each other in the direction of travel of the wire, and at least the ledges of the upper side are developed with suction; and a third section which has at least one suction wire separating element on one side. The twin-wire forming units are so arranged that the same drainage elements are associated in each case with what will be the inner and outer sides respectively of the respective layer of the multilayer paper web.
摘要:
Headbox for paper machines, provided with an output channel in the form of a nozzle, with an output slot for producing a strip of pulp having the width of the machine. The output channel is delimited by two flow guide walls converging toward one another and as a rule by a rear wall. It is divided up into a number of channel sections (32), preferably autonomous, by subdivision of the flow guide walls into wall sections (30, 31) and preferably by subdivision of the rear wall into rear wall sections (37). Each channel section may have at least one input line (40) of its own, as well as (for adjusting the opening of the output slot) a section of part of the mobile wall (35) and an associated regulating system (38, 39).
摘要:
A twin-wire former for the production of a web of paper from a fiber suspension. An upper endless loop of wire belt having a lower horizontal run and a lower endless loop wire belt having an upper horizontal run. Guide rolls support the wire belts to define a twin-wire zone. The upstream inlet wedge of the twin-wire zone is disposed at the outlet from a head box. The initial part of the path of the twin-wire zone has a gradual curvature convexly with respect to the lower wire belt, and in that initial portion are positioned guide tables, suction boxes and dewatering elements. This curved initial part is followed by a forming roll within the loop of the upper wire belt. The twin-wires wrap an arcuate sector of the lower region of the forming roll. A support roll follows the forming roll. The support roll is upraised sufficiently to wrap the twin-wires around the bottom of the forming roll and over an arcuate sector at the top of the support roll. Following the support roll, the upper wire separates from the lower wire. In the continuing generally horizontal, slightly descending path of the lower wire with the web on it are disposed a plurality of suction boxes and a lower wire suction roll to define a final dewatering path after the twin-wire zone.
摘要:
Wire section, guidance device, and process of forming a web in a machine for producing a fibrous material web. The device include two revolving endless wire belts, a twin wire zone formed between the two revolving endless wire belts, and a revolving flexible support belt located in a vicinity of the twin wire zone and positioned to support at least one of the two wire belts in a support region. The flexible support belt is generally guided along an at least essentially circular cylindrical path, and the support region includes a support path having an average curvature radius that is greater than a curvature radius of the essentially circular path. The process includes supporting at least one of the two endless wire belts with the flexible support belt in a support region, rotating the flexible support belt along a generally circular path, and deflecting the support belt from the generally circular path in the support region, whereby the support belt in the support regions travels along a support path. An average radius of curvature of the flexible support belt in the support path is greater than an average radius of curvature of the flexible support belt in the generally circular path.
摘要:
A dryer section is proposed, which is part of a machine for producing a material web, in particular a paper or cardboard web, with at least one dryer group that has a number of heatable dryer cylinders around which the material web is guided in a meandering path. The dryer section is distinguished by virtue of the fact that at least one pressing device (31) is provided inside the dryer section (1).
摘要:
A double screen former for the manufacture of a paper web has two continuous screens forming together a double screen zone. The one screen runs in the double screen zone across rigid laths that are arranged on the dewatering box at a mutual spacing. Additionally, the other screen runs in the double screen zone across several laths which are supported by means of flexible elements and can be forced on the screen at a selective force. The space between the flexibly supported laths is at least approximately twice as large as the space between the rigid laths.
摘要:
The breast box nozzle comprises a nozzle-type pulp stock duct formed by stream-guiding walls of the same width as the machine. The pulp stock duct is limited at its pulp stock discharge gap by a surface which extends over the width of the machine and is not touched by the pulp stock. Deposits in the area of the breast box nozzle which are caused by spray mists may cause defects in basis weight/cross section of the web being produced.The precipitation of the spray mist on the surface not touched by the pulp stock is prevented by a device which discharges a gaseous fluid into the space lying in front of this surface.