Abstract: A method and system for monitoring a separation process of a web in a paper machine in which the web is separated from a roll and passed into a free draw, which is preferably the first free draw of the web in the paper machine. A separation point of the web from the roll and a difference in speed of the web across the separation point, i.e., the draw difference, are measured. Cause-to-effect ratios in the separation process are established, e.g., in a data collecting system or analysis system, based on the measurements of the separation point and the speed difference. At least one additional process or running parameter of the paper machine is measured and the measurements of the separation point and the speed difference are compared with the additional process or running parameter(s) to thereby determine the manner in which the separation process of the web is affected by the additional process or running parameter(s).

Abstract: A roll for use in the manufacture of paper and board, a press roll, in particular a center roll in a press, a backup roll for an extended-nip press roll, a hot press roll, or equivalent, which is in direct contact with a wet paper web, or a calender roll, a method for manufacturing the same and a coating composition therefor including an adhesion layer arranged on the frame part of the roll and a ceramic layer arranged on the adhesion layer. The ceramic layer has a thickness of from about 100 &mgr;m to about 2000 &mgr;m and includes from about 50% to about 95% by weight of Cr2O3 and from about 3% to about 50% by weight of TiO2, or from about 50% to about 80% by weight of Al2O3 and from about 20% to about 50% by weight of ZrO2, or exclusively Al2TiO5. The outer face of the ceramic layer is finished until the roughness Ra is from about 0.2 &mgr;m to about 2.0 &mgr;m and/or the porosity of the outer face of the roll is from about 1% to about 20%.

Abstract: The invention concerns a heated roll and a method for heating of a roll, in particular of a press roll or calender roll in a paper or board machine. The roll has a hollow, tubular roll mantle. According to the invention, the roll is heated with electric current by means of electrical resistors fitted inside the body material of roll mantle. The heating is preferably applied to the roll substantially at the proximity of the face of the roll mantle, and the electric current may be supplied to the electrical resistors from the ends of the roll through glide rings.

Abstract: A method for regulating the loading of adjustable-crown roll having a stationary roll axle around which a roll mantle is rotatingly mounted, and of which roll a nip is formed with a backup roll. The deflection of the roll mantle and/or the linear load in the nip is regulated by loading elements and a backup zone supported on the roll axle and acting upon the inner face of the roll mantle in the direction of the nip plane. Upon the inner face of the roll mantle of the roll of the backup zone/zones, a sum force is produced which acts in the nip plane in a direction substantially opposite to the force produced by the loading element, and the force effect applied by the backup zone/zones to the inner face of the roll mantle is applied, examined in the direction of the circumference, to more than one point.

Abstract: A method and device for conditioning a ceramic or metal-ceramic coating of a paper machine roll at its operating site. The roll is ground periodically by a grinding member mounted on a doctor of the roll. The grain size of the grinding particles in the grinding member, i.e., the average diameter of the particles, is in the range of from about 15 to about 200 .mu.m. In the grinding situation, the roll is rotated in its site of operation, and the grinding member is pressed with a force into contact with the face to be ground, whereby, if the face to be ground is excessively rough, it is smoothed to the desired value of surface roughness and, in a corresponding manner, an excessively smooth face is roughened to the desired surface roughness value determined by the grinding member.

Abstract: The invention concerns a roll for use in the production of paper, in particular a center roll in a press section of a paper making machine, with which the web is in direct contact and from which the web is detached. In the invention, a composite structure has been formed onto the cylinder mantle of the roll. According to the invention, the roll face is provided with a surface layer which protects the roll from wear and which provides good properties for detaching of the web, this surface layer being formed by thermal spraying of a powder wherein metal and ceramic phases are in the same powder particle. The roll face is additionally provided with a dense layer for protection against corrosion, which layer is made of stainless steel whose chromium content is 10 to 29% and which layer is placed between the surface layer and the roll mantle. The function of the layer for protection from corrosion is to protect the roll mantle from corrosion and to promote the adhesion of the surface coating to the roll.

Abstract: The invention concerns a roll for use in the production of paper, in particular a center roll in a press section of a paper making machine, with which the web is in direct contact and from which the web is detached. In the invention, a composite structure has been formed onto the cylinder mantle of the roll. According to the invention, the roll face is provided with a surface layer which protects the roll from wear and which provides good properties for detaching of the web, this surface layer being formed by thermal spraying of a powder wherein metal and ceramic phases are in the same powder particle. The roll face is additionally provided with a dense layer for protection against corrosion, which layer is made of stainless steel whose chromium content is 10 to 29% and which layer is placed between the surface layer and the roll mantle. The function of the layer for protection from corrosion is to protect the roll mantle from corrosion and to promote the adhesion of the surface coating to the roll.