RU2305597C1 - Grinding member for drum mill - Google Patents

Abstract

FIELD: grinding engineering.

SUBSTANCE: grinding member comprises convex body of constant width provided with rounded ribs. The body is formed by the intersection of four spheres of the same diameter whose centers lie at the tops of a tetrahedron. The radii of the spheres are equal to the length of the tetrahedron edges. Three edges are rounded. The other three edges and all four tops are not rounded. According to the first version, three edges emanating from a single top are rounded. According to the second version, three ribs bounded one of the tetrahedron sides are rounded.

EFFECT: enhanced efficiency.

2 cl, 8 dwg

Description

The invention relates to techniques for fine grinding of solid materials and can be used in mining, cement, heat and power, chemical industries.

Known grinding element of a drum mill, made in the form of a ball, which is a convex body of constant width, with a width equal to its diameter [Quick reference technologist cement plant. / Ed. I.V. Kravchenko M., "Stroyizdat", 1974, p. 304].

The disadvantage of this grinding element of the drum mill is a small crushing effect due to the significant constant curvature of the surface of the ball, equal to its radius.

Known grinding element of a drum mill, made in the form of a tetrahedron with rounded ribs, faces and peaks [German Patent No. 440198, cl. B50C 15/30, 1927].

The disadvantages of this grinding element of the drum mill are small crushing effect due to the significant curvature of the rounding surfaces of the ribs and vertices of the tetrahedron, as well as the fact that this element is not a body of constant width and does not provide a dense packing of bodies with free transfer.

Closest to the proposed is the grinding element of a drum mill, made in the form of a convex body of constant width, the surface of which is formed by the intersection of four spheres of the same radius with centers located at the vertices of the tetrahedron, the radii of the spheres being equal to the length of the edges of the tetrahedron, and the vertices and ribs are rounded [Copyright certificate USSR No. 1388088 IPC: V02C 17/20, 1988 - prototype].

The disadvantage of this grinding element of the drum mill is a small crushing effect due to the significant curvature of the rounding surfaces of the ribs and vertices of the tetrahedron of constant width.

The technical problem solved by the proposed grinding element of a drum mill is to increase the efficiency of crushing of large pieces of crushed material.

The solution to this problem is achieved by the fact that the grinding element of the drum mill is made in the form of a convex body of constant width with rounded faces, the surface of which is formed by the intersection of four spheres of the same radius with centers located at the vertices of the tetrahedron, and the radii of the spheres are equal to the length of the edges of the tetrahedron, only any three edges are rounded, and the other three edges of the tetrahedron and all four vertices are not rounded, and the rounding surface of these edges is formed by rotation relative to the rounded edges of the tetrahedron the arc of the arc is contracted by a chord coinciding with the edge of the tetrahedron, and the radius of the arc is equal to the radius of the spheres.

The list of drawings.

Figure 1 - Front view of the grinding element (Option 1).

Figure 2 - Side view of the grinding element (Option 1).

Figure 3 - Top view of the grinding element (Option 1).

Figure 4 is a longitudinal section of a rounded rib.

Figure 5 - Cross section in the center of the rounded rib.

6 - Front view of the grinding element (Option 2).

7 is a side view of the grinding element (Option 2).

Fig - Top view of the grinding element (Option 2).

The grinding element (Option 1) of FIGS. 1 and 3 contains four vertices 1-4, which are the centers of four spherical surfaces of radius R, three rounded ribs 1-2, 1-3, 1-4, ribs 2-4, 4-3, 3-2 are not rounded. Figure 2 shows the life-size angle of intersection of two spherical faces with a non-rounded edge 4-2. A rounding arc 1-3 of radius R and a chord 1-3, which is both the face of the tetrahedron and the axis of rotation of the rounding arc 1-3 in section BB, are shown in FIG. 4. The formation of the rounding surface of the ribs is made by rotating an arc of radius R between the continuation of adjacent planes of the faces of the tetrahedron, the natural angle α between which for the tetrahedron is uniquely determined by its geometry, and the maximum radius of the rounding of the ribs r, equal to the height of the chord, is shown in section A-A of Fig. 5. The distances from the vertex 4 to the axis of rotation of the chord and from the top 2 to the axis of rotation of the chord, as well as from the axis of the tetrahedron to the axis of rotation of the chord, shown in Fig. 5, are uniquely determined by the geometry of the tetrahedron.

The essential distinguishing features of the proposed element from the prototype are the fillets of only three edges of the tetrahedron emanating from one vertex, and the other three edges of the tetrahedron and all four vertices are not rounded, and the fillet surface of these ribs is formed by rotation relative to the rounded edges of the tetrahedron of the arc, contracted by a chord coinciding with the edge tetrahedron, and the radius of the arc is equal to the radius of the spheres.

During the operation of the mill, grinding elements with their vertices 1, 2, 3, 4, rounded ribs 1-2, 1-3, 1-4, non-rounded ribs 2-4, 4-3, 3-2 and spherical faces 1-2- 3, 1-3-4, 1-4-2 and 2-3-4 have impact, crushing and abrasion effects on the particles of the crushed material and the latter are crushed. The effectiveness of the impact is the higher, the greater the concentration of stresses in the contact zone of the grinding element and the crushed particles of the material, therefore, the presence of four non-rounded peaks and three non-rounded ribs increases the intensity of grinding of the material.

The grinding element (Option 2) of FIGS. 6 and 8 contains four vertices 1-4, which are the centers of four spherical surfaces of radius R, three rounded ribs 2-4, 4-3, 3-2, and ribs 1-2, 1-3 1-4 are not rounded. Figure 7 shows the life-size angle of intersection of two spherical faces with a rounded edge 4-2. A rounding arc 2-4 of radius R and a chord 2-4, which is both the face of the tetrahedron and the axis of rotation of the rounding arc 2-4 in section BB, are shown in Fig. 4. The formation of the rounding surface of the ribs is made by rotating an arc of radius R between the continuation of adjacent planes of the faces of the tetrahedron, the natural angle α between which for the tetrahedron is uniquely determined by its geometry, and the maximum radius of the rounding of the ribs r, equal to the height of the chord, is shown in section A-A of Fig. 5. The distances from the vertex 4 to the axis of rotation of the chord and from the vertex 2 to the axis of rotation of the chord, as well as from the axis of the tetrahedron to the axis of rotation of the chord shown in Fig. 5, are uniquely determined by the geometry of the tetrahedron.

The salient features of the proposed element from the prototype are that only three ribs bounding one of the faces of the tetrahedron are rounded, and the fillet surface of these ribs is formed by rotation relative to the rounded ribs of the tetrahedron of the arc, contracted by a chord coinciding with the edge of the tetrahedron, the radius of the arc is equal to the radius of the spheres, and the other three edges and all four vertices are not rounded.

During the operation of the mill, grinding elements with their peaks 1-4, rounded ribs 1-2, 1-3, 1-4, non-rounded ribs 2-4, 4-3, 3-2 and spherical faces 1-2-3, 1- 3-4, 1-4-2 and 2-3-4 have an impact, crushing and abrasion effect on the particles of the crushed material and the latter are crushed. The effectiveness of the impact is the higher, the greater the concentration of stresses in the contact zone of the grinding element and the crushed particles of the material, therefore, the presence of four non-rounded peaks and three non-rounded ribs increases the intensity of grinding of the material.

By giving the grinding element such a shape that there are faces and vertices on its surface with intersection angles of the spherical surfaces, the crushing efficiency of large pieces of the crushed material when it collides with the grinding element is significantly increased.

Claims (2)

1. The grinding element of the drum mill, made in the form of a convex body of constant width with rounded ribs, the surface of which is formed by the intersection of four spheres of the same radius with centers located at the vertices of the tetrahedron, the radii of the spheres being equal to the length of the ribs of the tetrahedron, characterized in that there are only three ribs, emanating from one vertex are rounded, and the rounding surface of these ribs is formed by the rotation relative to the rounded edges of the tetrahedron of the arc with a contractible chord coinciding with the edge of the tetrahedron the arc diameter is equal to the radius of the spheres, the other three edges and all four vertices are not rounded. 2. The grinding element of the drum mill, made in the form of a convex body of constant width with rounded ribs, the surface of which is formed by the intersection of four spheres of the same radius with centers located at the vertices of the tetrahedron, and the radii of the spheres are equal to the length of the ribs of the tetrahedron, characterized in that there are only three ribs, bounding one of the faces of the tetrahedron, rounded, and the rounding surface of these ribs is formed by rotating relatively rounded edges of the tetrahedron of the arc with a contractible chord coinciding with the edge tetrahedron, the radius of the arc is equal to the radius of the spheres, the other three edges and all four vertices are not rounded.

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