CPC B31F 1/07 (2013.01) [B31F 2201/0715 (2013.01); B31F 2201/0779 (2013.01); B31F 2201/0782 (2013.01); B31F 2201/0784 (2013.01); B31F 2201/0787 (2013.01)] | 26 Claims |
1. A machine for embossing paper web products with two or more plies of paper web, comprising
at least one pair of embossing nips for plies of paper,
at least one laminating nip to bond said plies of paper,
at least two feed paths for plies of paper from an entrance of the machine toward said at least one laminating nip,
a pair of embossing cylinders, each embossing cylinder of said pair of embossing cylinders having on an outer surface thereof a respective plurality of embossing protrusions, said each embossing cylinder defining a section of one feed path of said at least two feed paths for at least one ply of said plies of paper in a form of a wrap angle for said at least one ply, and defining therebetween a transfer nip for said plies of paper,
a pair of pressure cylinders, each pressure cylinder of said pair of pressure cylinders being side by side with a respective said embossing cylinder, said embossing nip being defined between each pair formed of said embossing cylinder and said pressure cylinder,
a laminating device for assembly of said plies delivered from said transfer nip, to bond said plies,
at least one distribution device of material to facilitate ply-bonding arranged along said one feed path of said at least one ply upstream of said laminating device, wherein said distribution device of material to facilitate ply-bonding comprises a steam distributor arranged along said one feed path of said at least one ply in said machine, adapted to distribute steam on said at least one ply,
at least one heating device for at least one of said pair of embossing cylinders, wherein said at least one heating device comprises at least one electromagnetic induction device associated externally with a first embossing cylinder and/or a second embossing cylinder of said pair of embossing cylinders to heat an outer surface of said first embossing cylinder and/or said second embossing cylinder, said electromagnetic induction device being connected to a generator device to supply said electromagnetic induction device with electromagnetic induction currents adapted to generate an electromagnetic flow directed toward said first embossing cylinder and/or said second embossing cylinder, and wherein operating frequency of said electromagnetic induction currents is such as to generate eddy currents on said first embossing cylinder and/or said second embossing cylinder such as to prevalently follow a profile of the outer surface of said first embossing cylinder and/or said second embossing cylinder; and
at least one temperature sensor adapted to detect temperature of said first embossing cylinder and/or said second embossing cylinder with which said at least one electromagnetic induction device is associated, and wherein said generator device is controlled by a central control unit as a function of the temperature detected by said first temperature sensor varying said operating frequency and/or intensity of said electromagnetic induction currents, and said central control unit is configured to vary the operating frequency and/or the intensity of said electromagnetic induction currents based on the temperature of said first embossing cylinder and/or said second embossing cylinder; wherein the temperature detected by said at least one temperature sensor is the temperature of the outer surface of said first embossing cylinder and/or second embossing cylinder.
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