Rotary mill

An apparatus for grinding solid materials into particles comprising:

• a housing having an impact chamber defined within the housing;
• a rotor mounted in the impact chamber of the housing rotatable about a longitudinal axis of the rotor;
• the impact chamber of the housing having a peripheral wall surrounding the axis of the rotor;
• a feed opening in the peripheral wall of the impact chamber for receiving the solid materials from a feed system positioned above the feed opening for deposit onto the rotor so that rotation of the rotor acts to throw the solid materials against the peripheral wall;
• the rotor having a plurality of axially extending, angularly spaced impact hammers at its periphery for rotation about the axis of the rotor which is transverse to the feed opening;
• the rotor being positioned relative to the feed opening such that said plurality of impact hammers impact and deflect the solid materials entering through the feed opening, thereby fragmenting the solid materials to form finer and coarser particles;
• a plurality of shatter bars located at the peripheral wall of the impact chamber each extending axially along the peripheral wall at angularly spaced positions around the peripheral wall with the plurality of shatter bars arranged such that the plurality of shatter bars contact the deflected solid materials, thereby further fragmenting the solid material into said particles;
• an outlet chamber defined within the housing downstream of the rotor with the impact chamber and the second outlet chamber being connected such that the particles pass from the impact chamber to the outlet chamber;
• a finer particle outlet duct connected to the outlet chamber and arranged to receive the particles therefrom;
• a bottom discharge for allowing release of coarser particles from a bottom of the outlet chamber;
• an inclined guide wall at the feed opening in the peripheral wall of the impact chamber which is directed from the opening toward the rotor;
• the guide wall being inclined downwardly into the impact chamber and transversely across the opening so that the solid material slides along the guide wall into the chamber to the rotor;
• a bottom edge of the guide wall being located closely adjacent the plurality of impact hammers as they rotate with the rotor around the axis of the rotor so that the solid material is fed off the bottom edge of the guide wall onto the plurality of impact hammers;
• wherein the peripheral below the plurality of shatter bars includes a smooth surface portion surrounding the axis of the rotor into which a bed of the solid material collects at a bottom of the peripheral wall;
• so that the rotor cooperates with the smooth surface portion and the plurality of impact hammers on the rotor pass over the smooth surface portion and through the bed of the material thereon;
• wherein each of the impact hammers comprises a respective rectangular metal block which is rectangular in cross-section with a front face, a rear face, an inner face and an outer face;
• wherein each of the metal blocks extends longitudinally along the full length of the rotor and radially outwardly of the axis;
• wherein each of the plurality of impact hammers has along its axial length a respective leading blade element carried on and covering the front face of the respective metal block of the respective impact hammer, each leading blade element having a front face, an inner face, an outer face and a rear face;
• wherein each of the leading blade elements extends when viewed in cross-section radially outwardly of the axis of the rotor so as to engage and carry the solid material angularly forwardly around the axis of the rotor as it falls from the bottom edge and collects on said smooth surface portion;
• wherein each of said leading blade elements is formed of a hardened steel material harder than the respective rectangular metal block of the respective impact hammer;
• wherein the inner face of each leading blade element is narrower in an angular direction of the axis than the outer face of the leading blade element so that the front face is inclined to a radius of the axis with an outer edge of the front face angularly advanced relative to an inner edge of the front face;
• wherein the outer face of each leading blade element is coplanar with an outer face of the respective metal block.