A processing roll has a release layer that includes a porous rigid layer and polymer composite. The porous rigid layer may be a thermally sprayed metal that has discrete metal portions or a network of contiguous metal portions. Discrete metal from a flame sprayer may attached to each other on a contact surface to form the rigid layer. The polymer composite at least partially fills the spaces between the metal portions. The polymer composite may comprise a particulate filler, such as silica or glass beads. The release layer has good durability as the exposed surface contains both a portion that is the rigid material and a portion that is the polymer composite. This configuration enables very high release and long term durability even as the release layer wears.

A drying roller includes at least a cylindrical cylinder shell, two caps which are attached to both sides of the cylinder shell, and two journals which are indirectly fastened to the caps by way of a hollow shaft which is connected to the caps or are directly fastened to the caps, wherein the cylinder shell and the caps are welded to one another by way of an annular weld seam. The weld seam has a joint having at least two mutually opposite and parallel flange regions which are mutually spaced apart. A method for manufacturing a drying roller is also described.

A drying roller includes at least a cylindrical cylinder shell, two caps which are attached to both sides of the cylinder shell, and two journals which are indirectly fastened to the caps by way of a hollow shaft which is connected to the caps or are directly fastened to the caps, wherein the cylinder shell and the caps are welded to one another by way of an annular weld seam. The weld seam has a joint having at least two mutually opposite and parallel flange regions which are mutually spaced apart. A method for manufacturing a drying roller is also described.

A method for producing a Yankee dryer cylinder, or Yankee cylinder, comprises the steps of disposing of a first and of at least a second cylindrical portion of shell. These are made of steel, have the same diameter and are provided with a plurality of grooves at an internal surface. In particular, the portions of shell, at a respective end, are provided of respective flange portions. The method provides to coaxially position the portions of shell up to arrange respective coupling surfaces of the flange portions adjacent one to the other. Then the engagement of the portions of shell is provided by means of a plurality of clamping members, each of which arranged to clamp the adjacent flange portions. Then, it is provided the circumferential welding of the cylindrical portion of the shell that are opposite to the flange portions, and the removal of the clamping members and of the flange portions.

A method for producing a Yankee dryer cylinder, or Yankee cylinder, includes the steps of executing a cylindrical tubular semifinished product made of steel and having a side wall provided with an internal surface and an external surface. A forging step of the cylindrical tubular semifinished product follows for obtaining predetermined thicknesses at the central portion and at the terminal portions of the side wall where the enlarged terminal portions are made. The cylindrical shell is completed executing a plurality of grooves at the internal surface of the cylindrical tubular semifinished product. Then a plurality of longitudinal blind holes are executed at the external surfaces of the enlarged terminal portions of the cylindrical shell. Then, the heads are positioned at each of enlarged terminal portion of the cylindrical shell to which they are fixed by means of studs that pass the blind holes of the shell and respective through holes of which the heads are provided.

[Problem] To provide a method for spraying a chemical solution that makes it possible to uniformly apply a chemical solution onto a moving body and that exhibits excellent spraying efficiency. [Solution] The present invention is directed to a method for spraying a chemical solution in which, in a dry part D of a paper-making machine, a chemical solution is continuously sprayed onto a moving body that guides wet paper X, while a nozzle device S is reciprocating in directions orthogonal to a moving direction of the moving body with the moving body in motion, wherein: the moving body is a cylindrical dryer roller D1 or an endless canvas K1; and a travel distance H that the nozzle device S moves during a single rotation of the moving body and a width W of a sprayed area that is formed on the moving body by the nozzle device S satisfy the relationship represented by the following expression: 0.5H/W20.

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 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.

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.

A large-cylinder drying roller is provided with a divided hollow shaft for reasons of production. The divided hollow shaft has hollow-shaft parts which are capable of being inserted at both sides into a construction composed of a cylinder shell and caps connected thereto by a weld seam, and are capable of being thereafter connected to one another and to the caps.