Review of belt stretch in ViscoNip roller

The report was a finalization part of the thesis bachelor work in mechanical engineering at Karlstad University. A review of the ViscoNip roll belt stretch was made to Valmet. The background to the project was that the belts became resistant to wear, which meant that it was no longer necessary to adjust the machine direction. Previously the belt was moved in the machine direction to expose a new and fresh surface to even the wear. The increased quality of the belt has led to the possibility of applying a fixed side. The goal with the thesis work was to minimize the cost of the belt tension. The project has gone thru a development process where project planning, product specification, concept generation, concept evaluation and layout design was included. Through a cost analysis and input from the relevant fitters and service staff, it was found that a trapezoidal screw was a highly rated solution for the head adjustment. Due to the requirement for continuous belt tension, the trapezoidal screw and a fixed end could not be combined. As there were several advantages with the trapezoidal screw, a solution was created that was to combine a trapezoidal screw with a spring. These along with a fixed head became the winning concept. Before the thesis work, the cost of the ViscoNip roll belt stretch was 226 321 kr. In that price was installation, hydraulics, trapezoidal screw and displacement components. Upon completion of the thesis, a fixed side was applied to the driving side together with a trapezoidal screw combined with a driver's spring. The estimated cost was instead 155 477 kr, a saving of 70 845 kr