Patent DE-10022110-A1 (DE)
Title: A characteristic profile of a paper/cardboard web or a pulp suspension is set by a sectional and aligned acoustic field during production/finishing or at a coating station or glue press
Inventor: RONNENBERG DIETER
IPC: D21F1/44
Filed: 2000-05-08
Abstract: To set a web characteristic profile, in a paper/cardboard fiber web or a layer of pulp suspension (12), at least one acoustic field with a sectional alignment is used which is narrower than the web/suspension width. The acoustic field acts on the components of the web/suspension composition at a defined angle.  The characteristic profile is the Z-profile vertically through web/suspension, or the lateral profile across the machine running direction (16), on the plane of the web/suspension. The acoustic field is developed by a generator (22), which passes through a liquid transfer medium (27). At least one addition acoustic field is generated, to act on a section of the composition of the web/suspension, offset from the first field in the direction of machine running. The two acoustic fields act on the web/suspension simultaneously, with at least a partial interference between them. The second field can be developed by a reflection from the first acoustic field, at least partially. A standing wave acts on the components of the web/suspension composition as at least a partial reflection from an acoustic field. The alignment of the acoustic field is deflected by refraction, at the transit between solid and liquid materials. At least one acoustic field sets the layering of the components of the web/suspension composition, and the orientation of the fibers to the spatial axes, and the dry content of the web/suspension, the strength-to-weight ratio, the web/suspension flotation, the thickness of an applied coating of ink or glue, and to bond together two layers of webs/suspensions. At least one acoustic field has an intermittent action. The oscillation of at least one acoustic field is formed by at least two superimposed and overlaid oscillations of different frequencies. The acoustic field frequency is \-20000 Hz. An Independent claim is included for a paper/cardboard produced by the machine, where at least one characteristic profile is set by an acoustic field with a sectional and aligned orientation. Preferred Features: The web/suspension contains particles which can be magnetized, or particles with volume elasticity. The web/suspension can contain a metal strip which is fixed in position by at least one acoustic field. A further Independent claim is included for an apparatus to affect a characteristic profile of a fiber web/suspension with at least one sectional transmitter (22) to generate an acoustic field, and a liquid transfer medium (27) between the transmitter and the web/suspension. Preferred Features: The acoustic transmitter is at the fourdrinier section of the machine. Or the transmitter is at the web press section, with the transmitter surface directly at the press blanket or is aligned to the web to force out or heat water. The transmitter can also be at the web drying section, aligned directly at the web to raise the temperature of water within the fiber material. The transmitter can be at a web coating machine, and at a glue press, fitted with a feed line for the transfer medium. The transfer medium is taken from the transmitter at the highest point of the medium at the transmitter. The acoustic transmitter has at least one reflector (33), which is flat or in a parabolic concave curve. The reflector can also have a sawtooth shape. The reflector can be a hollow triple mirror of separate sheets. The transmitter housing is fitted with a sliding coating at the side against the web/suspension or the fourdrinier (2). The acoustic field is moved by a motor, and preferably a step motor. A number of acoustic fields can be applied to the web/suspension through the channels of a preferably star-shaped print head. At least one acoustic transmitter is mounted to a cross beam (57), across the machine. At least one acoustic transmitter is mounted on a rotating disk at the cross beam, with an adjustable swing angle (29).