Utveckling av mothållssystem till valsar
This Master Thesis is a product development project that has been carried out incooperation with Metso Paper Sundsvall AB. The task has been to develop a holdingsolution that generates force between two rolls and to evaluate the new solution withrespect to functionality, manufacturing, structural stability, costs, assembly etc. Theroll holding solution is a system that is part of a rollpress. The rollpress is used towash and dewater pulp. The existing solution creates forces that have to be absorbedby the gable of the press. The objective was to reduce the weight of the gable andreduce the material cost.The thesis work started with a feasibility study on pulp manufacturing and washprinciples, a study of the rollpress and the existing roll holding system was alsoperformed. Conceptual solutions were developed. The concepts were evaluated andone concept was chosen.The chosen solution uses hydraulics as source of power. Two hydraulic cylinders areplaced between the rolls, one close to each gable. The hydraulic cylinders pull therolls together. The forces in the gables are reduced since the forces are kept betweenthe rolls. The hydraulic cylinders contain functions that allow the distance betweenthe rolls to be changed between two fixed positions during operation. The distancecan be changed to adapt to different production levels.The bearing houses belonging to the movable roll can move around a joint. If the rollis exposed to forces higher than the design force the roll and the bearing houses move.The friction force is kept at a minimum by moving the bearing houses around a joint,which promotes lineload measurements. The lineload is generated when pulp passbetween the rolls. The developed solution includes components that allow lineloadmeasurement.