DK144584B - MOLD NAMELY MOVING OR BALL MILL - Google Patents

Description

(19) DENMARK ('£ |). \ | L5 /

m) (12) PRESENTATION WRITING ου 1 kkbSk B

DIRECTORATE OF THE PATENT AND TRADEMARKET SYSTEM

(21) Application No. 5114/75 (51) IntCI.3 B 02 C 17/22 (22) Submission day 19 · S © P · 1973 (24) Race day 19 · seP · 1973 (41) Aim. available Apr 24 1974 (44) Presented 5 Apr. 1982 (86) International application # - (86) International filing day (85) Continuation day - (62) Master application no -

(30) Priority 23 · Oct. 1972, 9023/72, AT 19 Jul. 1973 * 6354/73, AT

(71) Applicant OESTERREICHISCH-AMERIKANISCHE MAGNESIT AKTIENGESELLSCHAFT, 9545 Radenthein, AT.

(72) Inventor Erich Eigner, AT.

(74) Clerk of the Office of Industrial Excellence v. Svend Schønning.

(54) Mill, in particular pipe or ball = mill.

BACKGROUND OF THE INVENTION The present invention relates to a mill, in particular a pipe mill or a ball mill, having a multilayered, preferably square, cross-section with rounded edges and straight or slightly rounded sides, and in which milling may be done by the falling or rolling movement of the filling with paint. and paint bodies, the size of the paint EQ bodies, e.g. cylindrical grinding bodies or spheres constitute only a small fraction of the lateral length of the mill's cross-section, and the inside of the mill is clad with a number of armor plate annularly arranged consecutively and milled annular inserts rotated in the longitudinal direction of the mill or *

ISLAND

2, preferably at the same angle to each other.

In particular, the invention relates to a further design of the known mills of this kind, which have a square base cross-section with rounded edges and straight sides, as described in Austrian patent specification No. 239,634.

The invention will therefore be explained in the following in the light of this mill, but the explanation applies in a similarly modified form to other mills of the kind mentioned, insofar as these have square basic sections.

By appropriately selecting the radius of the rounding, this mill known per square square cross section can exert a considerable influence on the milling process, namely that a reduction of the radius of the rounding relative to the diagonal in the mill cross section produces an increase in the impact and an increase in radius. in the rounding, a reduction in the impact or an increase in the rubbing effect.

When rotating or mutually displacing the successive ring cutters, the mill creates a passage which, as a result of the square square cross-section of the mill, takes the form of a four-screw. In this embodiment, the grinding bodies receive a pulse of motion in the direction of the mill axis. Furthermore, in this screw-shaped design, the transport of the milling goods in the longitudinal direction of the mill will also be affected, which means that by appropriate selection of the rise of the screw and the direction of rotation of the screw, by introducing a corresponding displacement of the ring cutters, a braking or acceleration of the passage of the goods through the mill can be provided.

Thus, the gradient of this screw-like passage and the direction of rotation can be determined through the angle of rotation between the consecutive annular inserts.

Furthermore, the transport of the paint through the mill is highly dependent on the density of the paint. Lightweight floating materials tend to remain at the surface by a dense or heavy accumulation of paint bodies and thus, so to speak, swim and not penetrate the paint body. In particular, especially fine grinding, however, it is necessary to provide an intimate mixture of grinding bodies and grinding materials. The setting of the individual annular inserts with respect to each other at an angle up to 45 ° in the direction of rotation works for painting goods of relatively high density to be carried in the direction from the inlet to the outlet of the mill. When the ring cutters are displaced opposite to the direction of rotation, the transport ceases and the material is stiffened as a result of the propeller's tendencies for opposite directed transport.

The helical course formed by displacement of the annular shears of the passage through the mill has, as has been shown in practical operation and in experiments, also a certain sorting effect on the grinding bodies, so that the larger grinding bodies predominantly accumulate at the inlet, while the smaller paint bodies predominantly accumulate at the outlet. However, this effect is imperfect as it occurs only in connection with paint bodies, such as balls or cylindrical paint bodies with a maximum diameter of 40 mm.

However, in grinding that does not have to be fine grinding, it is also necessary to work with paint bodies with a diameter larger than 40 mm, e.g. paint bodies with a diameter of 60 to 70 mm, which corresponds to the size of the paint bodies in the second chamber of a multi-chamber mill.

In an economical grinding process, it is necessary that coarse grinding materials are painted with large grinding elements and that the size of grinding elements, e.g. ball size, is reduced with increasing material sophistication. This has so far been most often achieved by dividing the mill in its longitudinal direction into chambers, so that the individual grinding bodies, e.g. spheres of very different sizes could not mix with each other, while the paint could pass through slits in the chamber walls and thus still move into the chamber following the outlet.

In order to improve the sorting effect of said known mill on the grinding bodies and, first of all, this effect also extends to larger grinding bodies so that they remain in the section for the mill intended for them, an additional impulse is required. This applies in an analogous manner to all mills of the kind in question with a multilayered basic cross-section and straight or slightly rounded sides. Obtaining the additional impulse is the object of the present invention. The invention thus relates to a mill, in particular a pipe or ball mill having multilayered, preferably square, cross-section and rounded edges, as well as straight or slightly curved sides, in which the milling is effected by the falling or rolling movement of that of grinding bodies and grinding materials. existing filling, the size of the grinding bodies being only a small fraction of the lateral length of the basic cross-section of the mill, and the interior of the mill being lined with armor ring cutters arranged one after the other in the longitudinal direction of the mill, and in which each ring cutter is rotated or extended longitudinally. , preferably at the same angle. The characteristics then consist in that the ring cutter in the mill comprises plates which in the direction of passage of the painting goods extend obliquely in relation to the interior of the mill.

Such inclined plates may extend over the entire width of the annular cutter, but they may also extend over a portion of the ring cutter width while extending over the other portion of the ring cutter parallel or approximately parallel to the longitudinal axis of the mill. In a particular embodiment of the invention, at least every third, but preferably every other annular cut, has inclined plates. It is particularly advantageous if the mill has a square cross-section with rounded edges and straight sides and at least every third, but preferably every other annular cutter is composed of plates extending obliquely towards the interior of the mill in the direction of the milling material and that the plates are preferably arranged. is such that plates longitudinally of the mill parallel to the mill axis alternate with sheets extending obliquely to the mill axis, whereby the annular inserts of the parallel running mill mill axis are set relative to each other as well as those of the mill axis. Thus, oblique plates built up ring inserts are continued.

The slanting of the plates (angle 3) may be 5 - 30 °, preferably 5 ° - 15 °. The sloping surfaces of the plate need not form a straight line, but they may also be formed. of a concave curvature. Furthermore, plates which are not inclined in themselves need not be used, but, as the case may be, plates which extend parallel to the mill axis can also be used on the moldings to effect the bevel, and these moldings may extend at a desired angle, however different from 90 ° to the mill axis.

According to yet another embodiment of the invention, at any one time, a ring cutter with plates parallel to the mill axis and an adjacent ring cutter with inclined plates can be assembled into one unit, and each of these units can be positioned offset relative to the adjacent units. .

The angle of rotation or angle (angle a) of the ring cutters or units relative to each other may conveniently be between 15 ° and 50 °.

144584 5

Quite generally, it can be said that the ball-sorting or milling-sorting effect in a mill of the kind in question is to take place the sooner the higher the ring cutters are made up of inclined plates. If all the ring cutters have inclined plates, the ball sorting effect becomes the fastest, and in the individual grinding fractions, the sorting becomes more accurate when it comes to grinding bodies more than 60 mm in diameter. Furthermore, the use of inclined plates with constant bevel in all of the annular inserts has the advantage that only one plate form is required for dressing the mill. As you know, in the coarse grinding area of the mill there must be paint bodies of different sizes. The wind turbine ring can be optimally adapted to any painting material.

The best results are obtained in all cases with mills according to the invention when they have square basic cross-sections with rounded corners and straight sides, the radius of the rounded edges preferably being about 1/3 of the side square of the basic square. For mills with larger diameters to be able to reduce the loss of painting space to a minimum, in special cases you can switch from a square basic cross-section to a basic cross-section with multiple edges. However, in order to obtain the best possible results, the geometric conditions, namely the relationship between the side length and the rounding of the corners, must be complied with, for which purpose according to the invention may be used wholly or partially inclined plates.

The slanting of ring inserts on the plates is known per se, but only in connection with mills of circular cross-section (cf., for example, German Patent No. 462,188 and a report in the journal "Zement-Kalk-Gips" 9 (1956) , pp. 228 to 231). In the known embodiments, either all ring cutters are obliquely cut or the slopes (as evidenced by German Patent Specification 462,188) are steep and high and are formed by special housings, ie not by slanting of the armor plates. However, the appliances built under this system wear out very quickly. Only in the design according to the invention have we succeeded in obtaining a perfectly finished paint with sorting of the paint bodies and at the same time obtaining a slight wear on the armor ring. Particularly it is achieved when partly used ring inserts with plates parallel to the mill axis and which give a square cross-section, together with ring inserts consisting of plates with relatively low bevel, each second or every third ring insert being constructed with plates with bevels, in part where the ring cutters of the same type or the units, which consist of a ring cutter with parallel plates and a ring cutter with bevelled surfaces, are displaced relative to each other, thereby obtaining a perfectly finished paint with sorting of the paint units and at the same time low wear of armor. It may be mentioned here that, in known mills with circular cross sections, a sorting of paint bodies of a size greater than 60 mm or 40 mm respectively is effected, but that the sorting of small paint bodies with a size less than 40 mm and especially less than 20 mm poses significant difficulties. First, through the design of the mill armor which is the subject of the present invention, it is possible, as can be seen from test results, to obtain a completely satisfactory sorting of all grinding bodies without the mill having to be divided into chambers.

The design of a mill with a square cross-section and rounded corners and straight sides which are the subject of the invention will be described below with reference to two embodiments shown in the drawings.

FIG. 1 shows a cross-section through such a mill; FIG. 2 is a longitudinal sectional view of the mill with slanted and straight plates along line A-B; and FIG. 3 shows a section of the mill with only inclined plates, also in longitudinal section along line A-B.

The mill has a cylindrical sheath M in which, in the axial direction, ie in the longitudinal direction of the mill, there are built-in ring cutters which are arranged behind one another and which consist of armor plates. 2 denoted e · ^, ^ ... e ^, f ^. The reference numeral e still refers to annular inserts with plates which are parallel, while the plates bearing reference numerals with f are those which, at an angle β, extend towards the interior of the mill and which are disposed so as to incline it with an arrow suggested flow direction for the paint. The angle of inclination of these plates conforms to the requirements in each case, e.g. with regard to the nature of the painting material, etc., and to some extent also according to the width of the individual plates. In general, it has been found that a suitable size for the angle β may be in the range of 5 - 15 °, but in exceptional cases also different sizes, up to 30 ° or more, can give good results.

It is also possible to select the slope of successive ring shears f or, if there are many of them, of groups of ring shears, so that the slope thereof or groups thereof is different from the slope of the preceding or subsequent ring shears or groups of ring shears. . The width of the individual plates and thus of the individual ring inserts can e.g. be 250 mm or half thereof. In a particular embodiment, a ring cutter e and a ring cutter may be joined together so that through-going plates over that width can be used, which plates in a part of the dimension extending in the longitudinal direction of the mill are bent obliquely .

In order to clarify the summary of two and two ring cutters e and f for a group or unit, FIG. 2 applied the terms Ε1 · ..Ε4 to each of these annular pairs. These interconnecting ring inserts or units are rotated at an angle α to the subsequent and previous ring inserts (see Fig. 1). No such displacement occurs within such interconnecting ring inserts or units.

To clarify these shifts in FIG. 2, the joints between each ring cutter e and the adjacent ring cutter f are indicated by a finer line than the joints between successive units Ε · ^ -Ε2> ^ 2 ~ E3, etc. # The joints are shown with excessive width for clarity. In reality, their width is only 2-3 mm. By means of the lines drawn up more strongly, it must be expressed that along the respective joint there has been a mutual displacement or rotation of the ring cutters. The magnitude of this displacement or rotation of the annular inserts depends on the given circumstances, such as the nature of the grinding material, the desired rate of passage through the mill and so on. Good results can be obtained with a displacement of between 15 and 45 ° (angle <x), but this indication indicates no restriction in the choice of the actual possible displacements.

The order of annular inserts whose plates are parallel to the direction of the mill axis and which are thus not inclined and the plates whose orientation is deflected toward the interior of the mill can also be changed in such a way that only every third annular insert consists of deflected plates. Also the length division between ring cutters e with plates parallel to the mill axis and ring cutters f with deflected plates can be changed according to the requirements, so that e.g. in the sheath M are built in longer ring shears e and shorter shears f with deflected plates as related units in the sheath M.

The mill shown in FIG. 3, consists only of inclined plates f | ... f ^, while, moreover, of this embodiment of the invention, the same as in FIG. 2. In FIG. 1, the setting of the ring cutters or units is illustrated. In order not to obscure the drawing, only the inner contours of the first of the two units E1 and E2 are plotted in FIG. 2 (the plates f | and f ^ in Fig. 3), and thus are the inner edge contours of the inclined plates of ring inserts f ^ and f ^.

The magnitude of the shear angle α may vary between consecutive ring cutters e or f (or f ') or with the units E in the longitudinal direction of the mill. The alignment of the local pitch angles of the emerging screw, as defined at the beginning of the present description, is directed to the desired grinding process and the desired distribution or sorting of the grinding bodies. i.e. that the division of the grinding bodies by size depends on where you are in the longitudinal direction of the mill.

In order that the necessary sorting of the grinding bodies can also be maintained over a long period of operation, it is not necessary to provide a number of chambers separated by the mill formed in accordance with the present invention, but such partitions can usually be completely avoided, so that the mill only going to consist of a single chamber. Also, in extreme cases with respect to the paint body journeys used, it is only necessary to use a single partition throughout the mill, so that the mill will only contain two chambers. The effect of a mill designed according to the invention with a square basic cross-section with rounded edges and planar sides, in so far as the sorting of the grinding bodies is concerned, will be further elucidated in the following by a test result from the operation of such a mill.

In a tube mill with a length of 9 m and a diameter of 2.4 m, balls with sizes ranging from 20 to 60 mm were introduced in the following weight%:

Ball size mm 20 25 30 40 50 60 Weight% 20.2 20.2 16.8 16.85 14.30 11.65 The mill was right-turning in the direction of flow of the paint. The individual ring inserts had a width of 250 mm and were two and two united into one unit. In each of these units, the first ring cutter was rotated at an angle of 15 ° in a direction towards the first neighboring cutter and each other ring cutter had a bevel of 15 °.

The balls were filled in the form of an unsorted mixture. The filling rate was 26% and the mill was kept at a speed of 0.7 uk 'where ukrit = 0Itldr * / min ·' where D means the diameter of the mill in m / / so that the ball distribution reached stationary equilibrium. Then the distribution in sections 0 to 1.5 m, 1.5 - 3.0 m, 3.0 - 4.5 m, 4.5 - 6.0 m, 6.0 - 7.5 m and 7 was measured. 5 - 9.0 m in the flow direction of the material, giving the following results.

9 14Å584

Section O to 1.5 m Ball size

Diameter in mm 20 25 30 40 50 60 Weight% - - 0.5 10.9 30.4 58.2

Section 1.5 to 3.0 m Ball Size

Diameter imm 20 25 30 40 50 60 Weight% - 0.1 6.2 40.2 45.2 8.3

Section 3.0 to 4.5 m Ball Size

Diameter imm 20 25 30 40 50 60 Weight% - 2.1 41.0 47.0 9.9

Sections 4.5 to 6.0 m Ball size

Diameter in mm 20 25 30 40 50 60 Weight% 0.5 38.2 56.5 4.6 0.2 -

Section 6.0 to 7.5 m Ball Size

Diameter in mm 20 25 30 40 50 60 Weight% 29.5 67.2 3.3

Sections 7.5 to 9.0 m Ball size

Diameter in mm 20 25 30 40 50 60 Weight% 89.9 10.1

For control, in some experiments reverse direction was used, ie. the mill turned to the left as seen in the direction of flow of the paint. In spite of this, to enable the cargo to be transported in the same direction, the setting of the ring inserts (though only as far as every other insert was concerned) was also changed. The setting was 15 ° in the direction of rotation, ie to the left. The ball mixture and other conditions were completely similar. After 24 hours of operation, the following ball distribution was found: U4584 ίο

Sections 0 to 1.5 in Ball Size

Diameter in mm 20 25 30 40 50 60 Weight - - ~ 0.13 5.77 30.8 63.3

Section 1.5 to 3.0 m Ball Size

Diameter in mm 20 25 30 40 50 60 Weight - - 1.7 41.8 54.8 1.7

Section 3.0 to 4.5 m Ball Size

Diameter in mm 20 25 30 40 50 60 Weight - 1.6 31.4 45.8 21.2 -

Sections 4.5 to 6.0 m Ball size

Diameter in mm 20 25 30 40 50 60 Weight 1.3 38.8 56.1 3.8 —- - *

Section 6.0 to 7.5 m Ball Size

Diameter in mm 20 25 30 40 50 60 Weight 29.1 67.10 3.90 - - -

Sections 7.5 to 9.0 m Ball size

Diameter in mm 20 25 30 40 50 60 Weight 91.3 8.70 - - - -

Similar results as with balls are also obtained with cylindrical paint bodies and other paint bodies at any degree of filling. The design of the armor ring which is the subject of the invention makes it possible to completely or to a great extent give up dividing the individual chambers.

Claims (6)

144584 11 lo Mill, in particular tube or ball mill, having a multilayered, preferably square, cross-section with rounded edges and straight or slightly curved sides, and in which the grinding is effected by the descending or rolling movement of the filling with grinding and grinding bodies, the size of the grinding bodies only a small fraction of the lateral length in the basic cross-section of the mill, and the inside of the mill is clad with longitudinally arranged ring cutters of armor plates and single ring cuts which are rotated or set in the longitudinal direction of the mill, preferably at the same angle to each other. , that the mill cutter ring has plates (^ .... f ^, and f ^ ...... f ^) which extend obliquely in relation to the interior of the mill in the direction of painting. Mill according to claim 1, characterized in that the inclined plates ..... f ^ or f ^ ..... f ^) extend obliquely over the entire width of the annular insert. Mill according to claim 1, characterized in that the inclined plates extend only obliquely over one part of the ring cutting width, but over another part of the ring cutting width extend parallel or almost parallel to the longitudinal axis of the mill. A mill as claimed in any one of claims 1 to 3, characterized in that at least every third, preferably every other ring scanner, has inclined extending plates (f ^ .... f ^). Mill according to claim 4, with a square base cross-section with rounded edges and straight sides, characterized in that at least every third, preferably every other annular cutter (f ^ .. f ^ ...) is composed of slabs extending obliquely in proportion to the interior of the mill in the direction of passage of the milling material, and that the arrangement of the plates is preferably such that plates (e1 <.. e ^ ...) arranged in the longitudinal direction of the mill parallel to the mill axis, alternate with plates which extend obliquely relative to the mill axis, whereby the annular inserts (e ^ .. e ^ „..) formed by the plates extending parallel to the mill axis are set relative to each other, and the annular scales (f1 ... f4) are also relative to one another. Mill according to any one of claims 1-5, characterized in that the inclination (angle β) of the plates (f ^ .f ^ o, .f2 is 5 - 3o °, preferably 5 - 15 ° .