Grate plate for a pulp lifter of a grinding mill

A plurality of grate plates for use with a pulp lifter at a discharge end of a grinding mill having a cylindrical drum with an interior, each of the plurality of grate plates comprising:

• an outer edge, an inner edge, a leading side edge and a trailing side edge, the plurality of grate plates having complimentary side edges having complementary shapes so that the plurality of grate plates can be mounted to the pulp lifter to form a circular or annular array, with the leading side edge of each grate plate being adjacent the trailing side edge of an adjacent grate plate in the array;
• openings for passing through ground material particles of a predetermined size or smaller from the interior of the cylindrical drum towards the pulp lifter;
• and
• on a surface configured to face the interior of the cylindrical drum, one or more sections of lifter bars arranged so that the lifter bar sections on a number of adjacent grate plates complement each other to form lifter bars, wherein the lifter bar sections are shaped so that at least portions of the resulting lifter bars are inclined or curved in a first circumferential direction of the array relative to a radial line of the array intersecting the respective lifter bar or lifter bar portion,
• wherein at least portions of the complementary leading and trailing side edges of the plurality of grate plates are inclined or curved in a second circumferential direction of the array relative to a radial line of the array running through a point of intersection of the respective side edge with the outer edge,
• wherein the second circumferential direction is opposite the first circumferential direction.

A pulp lifter for use at a discharge end of a grinding mill having a cylindrical drum with an interior, the pulp lifter comprising:

• a circular or annular array of pulp lifter elements;
• and
• a grate plate attached to each of the pulp lifter elements, each of the grate plates comprising:
• an outer edge, an inner edge, a leading side edge and a trailing side edge, wherein the leading side edge and the trailing side edge have complementary shapes so that a series of grate plates can be mounted to the pulp lifter in a circular or annular array, with the leading side edge of each grate plate being adjacent the trailing side edge of an adjacent grate plate in the array;
• openings for passing through ground material particles of a predetermined size or smaller from the interior of the cylindrical drum towards the pulp lifter;
• and
• on a surface configured to face the interior of the cylindrical drum, one or more sections of lifter bars arranged so that the lifter bar sections on a number of adjacent grate plates complement each other to form lifter bars, wherein the lifter bar sections are shaped so that at least portions of the resulting lifter bars are inclined or curved in a first circumferential direction of the array relative to a radial line of the array intersecting the respective lifter bar or lifter bar portion,
• wherein at least portions of the complementary leading and trailing side edges of the grate plates are inclined or curved in a second circumferential direction of the array relative to a radial line of the array running through a point of intersection of the respective side edge with the outer edge,
• wherein the second circumferential direction is opposite the first circumferential direction.

A grinding mill comprising:

• a cylindrical drum arranged rotatably around its longitudinal axis;
• at least one inlet for receiving a continuous feed of material to be ground;
• at least one outlet for continuous discharge of ground material;
• a pulp lifter for guiding the ground material from the cylindrical drum to the outlet, the pulp lifter comprising a circular or annular array of pulp lifter elements;
• and
• a grate plate attached to each of the pulp lifter elements, each grate plate comprising:
• an outer edge, an inner edge, a leading side edge and a trailing side edge, wherein the leading side edge and the trailing side edge have complementary shapes so that a series of grate plates can be mounted to the pulp lifter in a circular or annular array, with the leading side edge of each grate plate being adjacent the trailing side edge of an adjacent grate plate in the array;
• openings for passing through the ground material particles of a predetermined size or smaller from the interior of the cylindrical drum towards the pulp lifter;
• and
• on a surface configured to face the interior of the cylindrical drum, one or more sections of lifter bars arranged so that the lifter bar sections on a number of adjacent grate plates complement each other to form lifter bars, wherein the lifter bar sections are shaped so that at least portions of the resulting lifter bars are inclined or curved in a first circumferential direction of the array relative to a radial line of the array intersecting the respective lifter bar or lifter bar portion,
• wherein at least portions of the complementary leading and trailing side edges of the grate plate are inclined or curved in a second circumferential direction of the array relative to a radial line of the array running through a point of intersection of the respective side edge with the outer edge,
• wherein the second circumferential direction is opposite the first circumferential direction.