A CYLINDRICAL SCREEN AND A METHOD OF MANUFACTURING IT

摘要

In a pressure screening device for separating undesired particles from a fibre suspension a cylindrical screen (2) is provided. The screen has an outer side and an inner side and is provided with a plurality of projections (19) on the outer side of the screen (2) which extend in the circumferential direction of the screen (2), grooves (17) formed on the inner side of the screen (2) and extending in a direction having an axial component, and screening passages in the form of slots (18) disposed in the area of each groove (17) and diverging from the inner side of the screen (2) towards its outer side. According to the invention, the projections (19), grooves (17) and slots (18) of the screen (2) are produced by working of a substantially planar screen plate bent into cylindrical shape subsequent to the working. Thereby it is possible to form a screen (2) having uniform slots (18), the width of which at the inner side of the screen (2) is only about 0.1 mm. The invention also relates to a method of manufacturing such a screen (2).