Abstract: A gap former, consisting of a double sieve former 3 which is made up by an inner sieve 4 and an outer sieve 5, is in the initial stage of the process wrapped around a roller press 8 with a diameter of at least 800 mm. After the sieves have traveled such that a given segment of the sieves is no longer in contact with the roller press, the segment enters between a number of contour brackets 10 and 11 at which time the segment is moving rather steeply downward. During this stage an upper layer 6 of paper or cardboard which has been compressed is deposited onto a lower layer 7 that is already resting on the primary longitudinal sieve 2.

Abstract: 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.

Abstract: 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.

Abstract: A twin screen paper forming apparatus is provided having upper and lower screens moving in a first direction and wrapping around a portion of a leading forming roller positioned at the beginning of a forming zone where the upper and lower screens converge to form a twin screen. At least one stationary forming element is positioned downstream of the leading forming roller to contact with the lower screen. A water guide element is also located in the region of the forming zone approximately at the start of the forming zone. At least one forming rail contacts the upper screen and a pulp suspension discharge nozzle is positioned, to prevent preliminary draining, upstream of the location where the upper and lower screens converge.