Sulzer-escher Wyss Limited

Karl Muller

Alfred Bubik

Hans K Dahl

Otto Hildebrand

Jorg Walter

Heinz Steckenreuter

Herbert Holik

Elmer Weisshuhn

Heinz Braun

Helmut Storr

Thomas Schaible

Josef Dom

In a double wire former of a paper machine, a first continuous wire (1) is fed onto an at least partially curved guiding surface (4) so as to converge with a second wire (2), wherein the guiding surface (4) is movable in a form-locked manner relative to the wires. After the dewatering section described above, a further guiding surface (7) follows which, in advantageous embodiments, has an opposite sense of curvature and is fixedly located.

Double wire former

In order to regulate dewatering of the fiber suspension and the formation of the paper web between the upper and lower wires of the papermaking machines, upper ledges are provided along with the upper wire. These upper ledges are particularly constructed so as to have uniform design. Between these upper ledges, there is left free the same distance or spacing. This distance is not smaller than the width of each upper ledge. The individual distances between the upper ledges can be closed by insertable inserts so that the dewatering can be forcibly accomplished at mutually separated zones. Along the lower wire, there are provided lower ledges at a table, and between these lower ledges, it can be adjusted varying distances or spacing therebetween. The mutual distance or spacing between the lower ledges, according to a favorable construction, is always greater than the width of the individual upper ledges plus the distance or spacing of an upper ledge from the next neighboring upper ledge. The lower ledges can be mounted at the table so as to be lengthwise displaceably and individually adjustable in the direction of the lower wire. The table can be selectably positioned vertically as well as horizontally relative to the lower wire. All of these measures also can be accomplished during operation of the papermaking machine. The individual lower ledges are elastically supported against the table and this table is elastically supported against its foundation. It is possible to undertake the web forming operation, during operation of the papermaking machines, in accordance with technological requirements and the time wise as well as localized situations, while protecting the paper web which is to be formed and equally the equipment which is to be operated.

Method of using a forming section of a papermaking machine

The wet section of a twin wire papermaking machine is provided with an open forming roll at the lower wire and with the combination of a suction box at the lower wire and a vacuum suction box at the upper wire. Furthermore, by selecting the elevational position or level of the individual wire sections there can be obtained particularly advantageous conditions for the operation of the papermaking machine throughout a wide field of application, especially heavy types of paper at relatively low operating velocities of the papermaking machine. Gap-former and hybrid-former constructions of the papermaking machine are possible.

Wet section for a twin wire papermaking machine

A twin wire former wherein the forming turbulence of a first forming section is quieted by a main forming roller. Behind the main forming roller, as viewed with respect to a predetermined direction of travel of the forming wires, there is accomplished a further forming of the paper web or sheet from the fiber stock suspension in a second forming section. Due to this arrangement there is possible optimum formation of the paper web or sheet with the use of very little dilution water for the fiber stock suspension. Additionally, due to intensive shear forces present in the second forming section flocks formed in the fiber stock suspension and the paper web or sheet at the region of the main forming roller, can be eliminated so that the structure of the paper web or sheet is made more uniform.

Twin wire former

The de-watering apparatus for a two-wire paper machine is constructed in such a manner that following the convergence of both wires, firstly, a uniform pressure at a forming roll is exerted on the suspension layer located between the wires. Subsequently, both wires pass de-watering rails which may be located in the upper and/or the lower wire. In this case, an under-pressure is exerted at least at the rails located in the upper wire. At least one further de-watering member then follows before both wires are separated again. The de-watering apparatus can also be used after a preliminary de-watering section, for example an endless wire, and also in the direct vicinity of a head box.

De-watering apparatus in a two-wire former

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.

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Ringgenweiler, Germany

Karl Muller