Headbox Slice Opening Arrangement : A developed version and a new one

Sammanfattning: The purpose of the headbox is to convert a flow of fiber suspension to a jet, with a thickness between 4 and 20mm and a width between 3 -8meters, depending on the paper machine model. To adjust the beam thickness, the lip adjustment arrangement is used. This master thesis was written to develop the headbox and the lip adjustment system, for paper machines with a width over 6 meters. In the beginning of the project much focus was layed on understanding the problem and develop the product and customer requirements of the Headbox. In order to utilize the entire idea space a number of idea generation methods were used. The evaluation of concepts were conducted with the method Analytic hierarchy process (AHP), which is a method for clarifying the decision pattern. From the evaluation of the concept, two concepts were chosen. A modification of the existing headbox and a new concept, which adjusts the slice opening with a number of elastic pockets and a wedge. To further evaluate the modified headbox concepts the Finite Element Method was used. During the simulations the elastic deformation was compared between the current and the modified solution. The second concept was developed by describing the new design and motivated the chosen material and structures.   Overall it can be said that the modification of the current headbox solves the main problem and maintains the current quality on the paper. The new and innovative solution enables a more exact adjustment of the lip opening and allows a larger potential of modularization.