Described herein are devices and methods for the drying of permeable and semi-permeable webs such as paper products in a physical environment with limited space while providing for higher flow rates. The devices and methods of the present invention are for use with rotating, foraminous shelled roll dryers and are implemented by redesigning the aspects of the devices and methods associated with exhausting spent drying gas.

A Yankee dryer cylinder (1) having a cylindrical shell (10) having a central portion (11), a first and a second end portion (12, 13) and a longitudinal axis (101). At an internal surface (14), the cylindrical shell (10) includes a plurality of circumferential grooves (15). The cylinder (1) includes a first and a second head (20, 30) fixed, respectively, to the end portions (12, 13) of the cylindrical shell (10). The shell (10) includes a first and a second group of circumferential end grooves (15a, 15b, 15a, 15b) positioned respectively at the first and the second end portion (12, 13) and a third group of circumferential grooves positioned at the central portion (11). The grooves of the first and of the second group have a width that is greater than the width of the circumferential grooves positioned at the central portion, to uniformly distribute the loads in operating conditions.

Yankee dryer cylinder (1) having a cylindrical shell made of steel (10), having a first and a second end opposite each other (11, 12) and provided with a plurality of circumferential grooves (15). The cylinder (1) includes a first and a second head (20, 30) made of cast iron and fixed respectively to the first and to the second end (11, 12) of the cylindrical shell made of steel (10). It is, furthermore, provided a hollow shaft (40) mounted inside the cylindrical shell (10) and connected to the first and to the second head (20, 30) at a first and a second end (41, 42), respectively. The cylinder is also provided with a first and a second bearing journal (50,60) fixed to the hollow shaft (40) at a respective end (41, 42).

A method for coating a drying cylinder of a drying apparatus for drying and/or smoothing a fibrous web includes carrying out the coating within the drying apparatus. A system including a coating unit for coating the circumferential surface of a drying cylinder and a drying apparatus, as well as a method for converting or producing a drying apparatus, are also provided.

The present disclosure relates to methods and apparatuses for removing water from a wet fibrous web. During the process of making a fibrous structure, a capillary dewatering apparatus remove water from a wet porous web. In some configurations, a capillary dewatering apparatus may include a capillary porous media. A molding member, such as a papermaking belt comprising an air permeable fabric, may advance the wet fibrous web onto the capillary porous media, wherein the fibrous web is positioned between the capillary porous media and the air-permeable fabric. An energy transfer surface may be positioned in contact with the air-permeable fabric or the outer circumferential surface, wherein the energy transfer surface operates to vibrate the capillary porous media. In turn, the vibration helps to drive water through the capillary porous media, allowing additional water to flow from the fibrous web and through pores in the capillary porous media.

A heatable roller suitable for a machine for producing and/or upgrading a web of material, in particular a fibrous material web such as a paper, paperboard or tissue web. The roller has a main element with a metallic and cylindrical roller wall which is heatable by suitable means and on the radially outer side of which there is, at least in sections, a coating. When the roller is used as intended, the coating provides a web contact side which can be brought into contact with the web of material. The coating includes, or is formed by, at least one metallic or metal-carbidic layer with a first layer component providing a matrix and a second layer component distributed in the matrix. The first layer component has a higher abrasion resistance than the second layer component and the second layer component has a greater thermal conductivity than the first layer component.

A dewatering roll (10) comprises a roll body (20), a mantle support structure (30) and a mantle (40). The mantle support structure (30) is attached around the roll body (20). The mantle (40) is attached against an outer surface (36) of the mantle support structure (30). The mantle (40) has a plurality of through holes (42) constituting mantle flow paths (44). The mantle support structure (30) presents support flow paths (38) from the outer surface (36) of the mantle support structure (30). The support flow paths (38) are in fluid contact with the mantle flow paths (44). The outer surface (36) of the mantle support structure (30) has a static geometric shape defining an envelope having a smaller radius in vicinity of each axial end (15) than in vicinity of a center (16). Thereby, the inner surface (48) of the mantle (44) assumes the shape of the envelope.

A Yankee dryer cylinder comprising a fixed hollow shaft provided with an inlet mouth through which a flow of hot air is fed into the cavity, and an outlet mouth through which the flow of hot air exits the dryer cylinder. The Yankee dryer cylinder provides, furthermore, a cylindrical shell having an internal surface and rotatably mounted about the fixed hollow shaft. Into the cavity a partition wall is provided which divides the fixed hollow shaft in a feeding portion and in a discharging portion.

Described herein are devices and methods for the drying of permeable and semi-permeable webs such as paper products in a physical environment with limited space while providing for higher flow rates. The devices and methods of the present invention are for use with rotating, foraminous shelled roll dryers and are implemented by redesigning the aspects of the devices and methods associated with exhausting spent drying gas.

A method for manufacturing a large-cylinder drying roller includes providing a cylindrical cylinder shell having two sides, initially attaching a respective cap to each of the sides of the cylinder shell, subsequently inserting an inner shaft coaxially within the cylinder shell and connecting the inner shaft to the caps and connecting journals to the inner shaft. The inner shaft is divided into two inner-shaft parts. Each inner-shaft part is inserted from a respective side and then each of the inner-shaft parts is connected to the other of the inner-shaft parts and to a respective one of the caps and/or prior to inserting the inner shaft, the cylinder shell and the caps are relieved of stress and the connection of the cylinder shell and the caps is checked from the inside or the cylinder shell and/or the caps are mechanically processed together.