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US 2003/0110660 A1Published application
Drying section and a smoothing apparatus for such a drying section
AssigneeVoith Paper Patent GmbH
InventorJens Muller
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AssigneeVoith Paper Patent GmbH
InventorJens Muller
Estimating the term…
A drying section of a machine for the manufacture of a material web, in particular of a paper or of a board web, comprises a smoothing nip which is extended in the web running direction and is formed between two pressing areas lying opposite one another of which at least one is formed by a shoe roll, with at least 70%, and preferably at least 90%, of the outer shoe roll diameter lying above the machine base. In a method for the combined drying and smoothing of a material web, in particular of a paper web or of a board web, in a drying section, the following steps are provided: the material web is first dried to a pre-settable drying content>60%, in particular >65%, and preferably >70%; the material web having this pre-settable drying content is guided through a smoothing nip which is extended in the web running direction and is formed between two pressing surfaces lying opposite one another of which at least one is formed by a rotating belt and of which at least one is heated; the pressing time resulting in the extended smoothing nip is selected >0.8 ms; and the material web is further dried after the smoothing nip.
A drying section (10) of a machine for the manufacture of a material web (22), in particular of a paper web or of a board web, comprising a smoothing nip (12) which is extended in the web running direction (L) and is formed between two pressing areas lying opposite one another of which at least one is formed by a shoe roll (14), with at least 70%, and preferably at least 90%, of the outer shoe roll diameter lying above the machine base (16).
A drying section in accordance with any one of the preceding claims, characterized in that one of the two pressing surfaces is formed by a shoe roll (14) and the other is formed by a roll or by a cylinder, in particular by a drying cylinder (18), with a jacket not flexible in comparison with the shoe roll jacket (44).
A drying section in accordance with any one of the preceding claims, characterized in that at least one of the two pressing surfaces is heated.
A drying section in accordance with any one of the preceding claims, characterized in that at least one of the two pressing surfaces is provided as a heated smoothing surface.
A drying section in accordance with any one of the preceding claims, characterized in that the shoe roll (14) is insulated toward the environment by a hood (62) with simultaneous inner cooling, e.g. by means of the lubricating oil.
A drying section in accordance with any one of the preceding claims, characterized in that the shoe roll (14) provided with a hood (62) is cooled by cooling air from the inside and/or outside.
A drying section in accordance with any one of the preceding claims, characterized in that a damping device is provided in front of the extended smoothing nip (12) in the web running direction (L) for the sectional influencing of the web moisture transversely to the web running direction (L).
A drying section in accordance with any one of the preceding claims, characterized in that the extended smoothing nip (12) is arranged in a single row drying group.
An apparatus for smoothing a material web (22), in particular a paper web or a board web, in particular for use in a drying section (10) in accordance with any one of the preceding claims, comprising a smoothing nip (12) which is extended in the web running direction (L) and is formed between two pressing surfaces lying opposite one another of which at least one is formed by a shoe roll (14) and of which at least one is heated, with preferably one of the two pressing surfaces being formed by a shoe roll (14) and the other being formed by a drying cylinder (18).
An apparatus in accordance with any one of the preceding claims, characterized in that, to increase the bending moment, the drying cylinder (18) has an outer diameter>1.5 m, in particular >1.8 m, in particular 2 m, and preferably >2.4 m, and/or a ribbed inner peripheral surface.
An apparatus in accordance with any one of the preceding claims, characterized in that the drying cylinder (18) is deflection controlled.
An apparatus in accordance with any one of the preceding claims, characterized in that at least one of the two pressing surfaces is heated and has a surface temperature>40° C., preferably >60° C.
An apparatus in accordance with any one of the preceding claims, characterized in that the smoothing nip (12) is arranged within a wire loop.
An apparatus in accordance with any one of the preceding claims, characterized in that the flexible jacket (44) of the shoe roll (14) is temperature resistant up to approximately 120° C. and preferably consists of a correspondingly thermally loadable plastic.
An apparatus in accordance with any one of the preceding claims, characterized in that the oil used for lubrication in the shoe roll (14) is temperature resistant up to 120° C.
An apparatus in accordance with any one of the preceding claims, characterized in that the outer diameter of the jacket (44) of the shoe roll (14) is ≦1.8 m.
An apparatus in accordance with any one of the preceding claims, characterized in that one of the two pressing surfaces is formed by a shoe roll (14) and the other is formed by a drying cylinder (18);
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe roll (14) includes a centrally fixed shoe (38).
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe roll (14) includes a shoe (38) cooled by the relevant lubricating oil.
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe roll (14) is provided with means to eliminate the friction which arises between the shoe (38) and the associated pressing unit (48) due to thermal expansion.
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe (38) of the shoe roll (14) can be acted upon sectionally in the transverse direction.
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe roll (14) is insulated toward the environment by a hood (62) with simultaneous inner cooling, e.g. by means of the lubricating oil.
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe roll (14), which is preferably provided with a hood (62), is cooled with cooling air from the inside and/or from the outside.
An apparatus in accordance with any one of the preceding claims, characterized in that a hood (62) is associated with the shoe roll (14) and can be opened upwardly and to the sides at least so far that the opening created is dimensioned at least as large as the outer diameter of the shoe roll (14) and is preferably dimensioned 1.5 times to 2 times larger than the outer diameter of the shoe roll (14).
An apparatus in accordance with any one of the preceding claims, characterized in that the edge regions of the two pressing surfaces not covered by the material web (22) have a spacing (d) from one another, in particular in the smoothing nip plane.
An apparatus in accordance with any one of the preceding claims, characterized in that the drying cylinder (18) is conically shaped at the edges, and/or the stroke (h) of the shoe (38) associated with the shoe roll (14), is dimensioned such that a spacing (d) results with respect to the opposing pressing surface at the outer edges (42) of the rotating shoe roll jacket (44), which spacing (d) is >5 mm, in particular >8 mm, and preferably >12 mm.
An apparatus in accordance with any one of the preceding claims, characterized in that the drying cylinder (18) is made in stages.
A method for the combined drying and smoothing of a material web (122), in particular of a paper web or of a board web, in a drying section (110), in which
A method in accordance with any one of the preceding claims, characterized in that Ra (mean roughness value) is <4 μm, and preferably <3 μm, for at least one of the two pressing surfaces.
A method in accordance with any one of the preceding claims, characterized in that the two pressing surfaces have a different smoothness.
A method in accordance with any one of the preceding claims, characterized in that at least one of the two pressing surfaces is provided as a heated smoothing surface.
A method in accordance with any one of the preceding claims, characterized in that a damping device is used in front of the extended smoothing nip (112) in the web running direction (L) for the sectional influencing of the web moisture transversely to the web running direction (L).
A method in accordance with any one of the preceding claims, characterized in that the extended smoothing nip (112) is provided in a single-row section (110) or drying group.
An apparatus for smoothing a material web (122), in particular a paper web or board web, in particular for carrying out the method in accordance with any one of the preceding claims, comprising a smoothing nip (112) which is extended in the web running direction (L) and is formed between two pressing surfaces lying opposite one another of which at least one is formed by a rotating belt (144) and of which at least one is heated.
An apparatus in accordance with any one of the preceding claims, characterized in that Ra (average peak-to-valley height) is <4 μm, and preferably <3 μm, for at least one of the two pressing surfaces.
An apparatus in accordance with any one of the preceding claims, characterized in that the two pressing surfaces have a different smoothness.
An apparatus in accordance with any one of the preceding claims, characterized in that at least one of the two pressing surfaces is provided as a heated smoothing surface.
An apparatus in accordance with any one of the preceding claims, characterized in that a damping device is used in front of the extended smoothing nip (112) in the web running direction (L) for the sectional influencing of the web moisture transversely to the web running direction (L).
An apparatus in accordance with any one of the preceding claims, characterized in that one of the two pressing surfaces is formed by a rotating belt (144) or by a shoe unit (114) and the other is formed by a drying cylinder (118).
An apparatus in accordance with any one of the preceding claims, characterized in that the drying cylinder (118) is deflection controlled.
An apparatus in accordance with any one of the preceding claims, characterized in that at least one of the two pressing surfaces is heated and has a surface temperature (T)>40° C., preferably >60° C.
An apparatus in accordance with any one of the preceding claims, characterized in that the web running speed is >450 m/min, and preferably 1200 m/min.
An apparatus in accordance with any one of the preceding claims, characterized in that the web residence time in the smoothing nip is >0.8 msec, in particular >2 msec, and preferably >4 msec, and/or the shoe length measured in the web running direction is >30 mm, and preferably >60 mm.
An apparatus in accordance with any one of the preceding claims, characterized in that the smoothing nip (112) is arranged inside a wire loop.
An apparatus in accordance with any one of the preceding claims, characterized in that at least one of the two pressing surfaces is formed by a rotating belt (144), in particular a rotating belt associated with a shoe unit (114), which is temperature resistant up to approximately 120° C., with the belt (144) preferably consisting of a correspondingly thermally loadable plastic.
An apparatus in accordance with any one of the preceding claims, characterized in that the rotating belt (144) consists of elastomeric material on a polymer base, e.g. of polyurethane.
An apparatus in accordance with any one of the preceding claims, characterized in that the oil used for lubrication in the respective shoe unit (114) is temperature resistant up to 120° C.
An apparatus in accordance with any one of the preceding claims, characterized in that the rotating belt (144) is formed by the jacket of a shoe roll (144) whose outer diameter is ≦1.8 m.
An apparatus in accordance with any one of the preceding claims, characterized in that one of the two pressing surfaces if formed by a shoe roll (144) and the other is formed by a drying cylinder (118);
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe unit (114) includes a centrally fixed shoe (138).
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe unit (114) includes a shoe (138) cooled by the relevant lubricating oil.
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe unit (114) is provided with means to eliminate the friction arising between the shoe (138) and the associated pressing unit due to thermal expansion.
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe unit (114) includes a shoe (138) which is sectioned in the transverse direction and via which the smoothness can be sectionally influenced in the transverse direction.
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe unit (114) is insulated toward the environment by a hood (162) with simultaneous inner cooling, e.g. by means of the lubricating oil.
An apparatus in accordance with any one of the preceding claims, characterized in that the shoe unit (114) provided with a hood (162) is cooled with cooling air from the inside and/or from the outside.
An apparatus in accordance with any one of the preceding claims, characterized in that the edge regions (140) of the two pressing surfaces not covered by the material web (122) have a spacing (d) from one another, in particular in the smoothing nip plane.
An apparatus in accordance with any one of the preceding claims, characterized in that the drying cylinder (118) is conically shaped at the edges (140), and/or the stroke (h) of the shoe (138) associated with the shoe unit (114), is dimensioned such that a spacing (d) results with respect to the opposing pressing surface at the outer edges (142) of the rotating shoe roll jacket (144), which spacing (d) is >5 mm, in particular >8 mm, and preferably >12 mm.
An apparatus in accordance with any one of the preceding claims, characterized in that the drying cylinder (118) is made in stages.
An apparatus in accordance with any one of the preceding claims, characterized in that the drying or smoothing cylinder (118) is heated from the outside, e.g. electrically, by steam and/or the like.
An apparatus in accordance with any one of the preceding claims, characterized in that the drying or smoothing cylinder (118) is sectionally heatable considered in the transverse direction and thereby the sectional moisture of the material web can be correspondingly influenced such that the transverse smoothness profile can be correspondingly controlled and/or regulated.
An apparatus in accordance with any one of the preceding claims, characterized in that a hood (162) is associated with the shoe roll (114) and can be opened upwardly and to the sides at least so far that the opening created is dimensioned at least as large as the outer diameter of the shoe roll (114) and is preferably dimensioned 1.5 times to 2 times larger than the outer diameter of the shoe roll (114).
A drying section (110) of a machine for the manufacture of a material web (122), in particular a paper web or a board web, comprising a smoothing apparatus in accordance with any one of the preceding claims.
A drying section in accordance with any one of the preceding claims, characterized in that at least 70%, and preferably at least 90%, of the outer shoe roll diameter lies above the machine base (116).
A drying section in accordance with any one of the preceding claims, characterized in that the shoe roll (114) lies completely over the machine base (116).
A drying section in accordance with any one of the preceding claims, characterized in that spacers can be used between the bearing of the shoe unit (114) and a bearing block and /or in that cantilever elements can be used.
Dependencies are inferred from the claim text.