a continuous stream of the slurry to a series of narrow nips located between a pair of revolving rolls the widths of the nips being less than that which would cause the slurry carrying a major portion of the fibers to enter the spaces between the sides of the nips as the rolls revolve and pressing the revolving rolls together with a predetermined force adequate to provide the desired effect on the fibers from the slurry that pass between the nips the narrow nips have contacts thereon whose widths do not exceed significantly the lengths of the longest fibers in the slurry so the contacts generally have widths not exceeding about 9 mm and preferably of 3 mm or less by so adjusting the relationship between the row of intermittent contacting widths in the nips they grab and dewater the fibers before crushing them allowing the water to flow through the spaces between the contacting widths this action will not happen if the contacts are much wider than the longest fibers in the slurry because in that case the individual nips would push the slurry sideways to the openings and not allow them to grab any but a tiny proportion of the fibers in the preferred embodiment of the invention there are a large number of contacting elements along the length of the roll each element preferably having a width of less than three times the average lengths of the fibers in the pulp with channels between the elements of sufficient size to permit passage of the water squeezed from the pulp by adjacent elements thus the spacing between the contacts is insufficient to cause most of the slurry presented to them to be pushed.