APPARATUS FOR GRINDING FIBROUS SHEET MATERIAL Russian patent published in 2000 - IPC

FIELD: pulp-and-paper industry, in particular, production of paper by aerodynamic method. SUBSTANCE: apparatus has pregrinding device formed as rotor with blades staggered on its surface, contraction-diffuser connecting channel, centrifugal breaker, outlet channel, centrifugal fan mounted in outlet channel and connected to centrifugal breaker via central opening, which is axially closed with centrifugal breaker disk. Hopper of pregrinding device has air supply branch pipe whose axial section is extending tangentially of rotor surface. Hopper part adjoining branch pipe is formed as curved axis channel running around one side of rotor. Curved axis channel section corresponds to that of branch pipe. During operation of grinding apparatus material is ground by rupturing without shortening of fibers. Rupturing of fibers is facilitated by preliminary wetting of material. EFFECT: increased efficiency and improved quality of produced paper. 11 cl, 2 dwg