US3880365A - Mill - Google Patents

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Publication number
US3880365A
US3880365A US406665A US40666573A US3880365A US 3880365 A US3880365 A US 3880365A US 406665 A US406665 A US 406665A US 40666573 A US40666573 A US 40666573A US 3880365 A US3880365 A US 3880365A
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United States
Prior art keywords
mill
annular
shell
axis
liner plates
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Expired - Lifetime
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US406665A
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English (en)
Inventor
Erich Eigner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Osterreichisch Amerikanische Magnesit AG
Midland Ross Corp
Grimes Aerospace Co
Original Assignee
Osterreichisch Amerikanische Magnesit AG
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Filing date
Publication date
Priority claimed from AT902372A external-priority patent/AT319715B/de
Priority claimed from AT635473A external-priority patent/AT332199B/de
Application filed by Osterreichisch Amerikanische Magnesit AG filed Critical Osterreichisch Amerikanische Magnesit AG
Application granted granted Critical
Publication of US3880365A publication Critical patent/US3880365A/en
Assigned to MIDLAND-ROSS CORPORATION reassignment MIDLAND-ROSS CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). 12/31/86 - DE Assignors: MIDLAND-ROSS CORPORATION, (MERGED INTO) N, MRC ACQUISTION CORP.
Assigned to FL AEROSPACE CORP. reassignment FL AEROSPACE CORP. CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE JULY 14, 1987 (DELAWARE) Assignors: MIDLAND-ROSS CORPORATION
Assigned to CAPITOL CASTINGS ACQUISITION, INC. reassignment CAPITOL CASTINGS ACQUISITION, INC. RE-RECORD OF AN INSTRUMENT RECORDED 3/21/88, REEL 4840, FRAMES 688-690, TO CORRECT PATENT NUMBER 3,800,365 TO 3,880,365. Assignors: FL AEROSPACE CORP.
Assigned to MIDLAND-ROSS CORPORATION reassignment MIDLAND-ROSS CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). EFFECTIVE - 9/11/86 Assignors: MRC MERGER CORP.
Assigned to MIDLAND-ROSS CORPORATION reassignment MIDLAND-ROSS CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). EFFECTIVE, 11/21/86 Assignors: MIDLAND-ROSS CORPORATION, (MERGED INTO), MRC OPERATING CORP.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/18—Details
    • B02C17/22—Lining for containers

Definitions

  • ABSTRACT A mill having a shell and a substantially square cross section with rounded corners and including a plurality of liner plates being aligned along the axis of the shell, interior surfaces of the plates defining annular courses at least a portion of which are inclined toward the axis and a portion of which are parallel to the axis, with adjacent courses being angularly displaced.
  • This invention relates to a mill, particularly a tube mill or ball mill, which has an interior polygonal, preferably square, cross section with rounded corners and straight or mildly curved sides, and in which the grinding action is performed by the falling and rolling motion of the contents or filling which consists of the grinding elements and the material to be ground.
  • the size of the grinding elements which usually are short cylinders or balls, is only a small fraction of the side length of the basic cross section of the mill interior.
  • the interior of the mill contains liner plates arranged in a series of annular courses arranged one behind the other in the longitudinal direction of the mill, and individual annular courses formed by these plates are angularly displaced or offset relative to each other, preferably by equal angles.
  • the invention relates particularly to a further development of the known mill ofthat kind having a square basic cross section with rounded corners and straight sides (Austrian Patent Specification 239,634).
  • the grinding action can be strongly influenced by the selection of a proper radius for the rounded corners.
  • a decrease of the radius of the rounded portion relative to the diagonal of the cross section of the mill will result in a stronger impacting action on the contents and an increase of the radius of the rounded portions will result in a lighter impact and in a stronger frictional action.
  • a passage is formed in the mill which, owing to the square basic cross section of the mill, is similar in shape to a four-thread screw. Owing to this design, an additional impulse in the direction toward the axis of the mill is imparted to the grinding elements.
  • the helical design also influences the flow of the material being ground in the longitudinal direction of the mill. The flow of the material being ground can be decreased or increased by a suitable selection of the lead or hand of the helical passage resulting from the offset of the annular courses. The lead of this helical passage is determined by the selection of the angle between successive annular courses.
  • the movement through the mill of the material being ground also depends strongly on the specific gravity of the material being ground. Easily flowing materials to be ground in a dense bed of grinding elements tend to remain on the surface and virtually float rather than enter the bed of grinding elements. On the other hand, a thorough mixing of the grinding elements and the material being ground is required particularly for a very fine grinding. If the individual annular courses are rela tively offset by up to 45 in the direction of rotation, material to be ground which has a higher specific gravity will move from the inlet of the mill to its outlet. If the annular courses are offset in a direction opposite to the direction of rotation of the mill, the material movement will be arrested, because the effect of each of these is to promote movement in opposite directions.
  • An additional impulse is required to improve the sorting action on the grinding elements in the abovementioned known mill and particularly to provide a sorting action also for larger grinding elements so that they remain in a desired region of the mill. This holds analgously true for all mills of the present kind which have a polygonal basic cross section with rounded corners and straight or mildly curved sides. It is an object of the present invention to provide such additional impulse.
  • the mill of this invention is composed of a circular shell with a polygonal interior cross section, preferably of square cross section with rounded corners and straight or mildly curved sides, and in which the grinding action is performed by the falling and rolling motion of the filling consisting of the grinding elements and the material to be ground, the size of the grinding elements being only a small fraction of the side length of the basic cross section of the mill.
  • the interior of the mill is provided with liner plates arranged in a series of annular courses arranged one behind the other in the longitudinal direction of the mill. Individual annular courses formed by these plates are angularly displaced or offset relative to each other, preferably by equal angles.
  • Annular courses of the mill are formed by plates (f, .f or f, .f which have at least a portion of their inside surface inclined toward the axis of the mill and in the direction of travel of the material being ground.
  • plates are referred to hereinafter as inclined plates.
  • the inside surfaces of the inclined plates may be inclined throughout their width or they may be inclined only throughout part of their width whereas the remainder of the inside surfaces of the inclined plates extend parallel or almost parallel to the longitudinal axis of the mill.
  • annular course comprising plates having inside surfaces which are parallel to the axis of the mill and an adjacent annular course which comprises inclined plates may be co mbined in a unit and each of said units may be angularly offset from the adjacent unit.
  • the angle (a) by which the annular courses or units are angularly spaced or offset relative to each other may preferably be between and 50.
  • Annular courses of plates having inclined inside surfaces are known per se but only in mills having a circular cross section (see, e.g., German Patent Specification 462,188 and the article in the periodical Zement- Kalk-Gips" 9( l956), pages 228-231).
  • each annular course has an inclined inside surface or the inclined surfaces are steep and high and are formed by separate internal fixtures (as in the German Patent Specification 462,l88) rather than by inclined linear plates. That system is subject to heavy wear.
  • a mill formed in accordance with this invention and particularly the combination of annular courses wihch consist of plates having inside surfaces that are parallel to the mill axis to provide for a square cross section of flow, and annular courses of plates whose inside surfaces have a relatively small inclination in such a manner that every other or every third annu lar course is composed of inclined plates, whereas adjacent annular courses are angularly offset, will provide satisfactory grinding as well as sorting of the grinding element and also a small wear of the liner plates.
  • FIG. 1 is a transverse schematic sectional view showing a mill formed in accordance with this invention
  • FIG. 2 is a longitudinal sectional view taken along the line A-B of FIG. 1 showing a portion of a mill having straight and inclined liner plates in accordance with one embodiment
  • FIG. 3 is a longitudinal sectional view taken along the line AC of FIG. 1 showing a portion of a mill having combined straight and inclined liner plates in accordance with a second embodiment of this invention.
  • FIG. 4 is a longitudinal sectional view taken along the line AB of FIG. 1 showing a portion of a mill having only inclined plates in accordance with a third embodiment.
  • FIGS. 1 and 2 An example of the first embodiment of which is illustrated in FIGS. 1 and 2.
  • the mill 10 has a cylindrical shell 12, in which annular courses 14 are formed by annular liner plates 15. These courses 14 are arranged one behind the other in the axial or longitudinal direction of the mill 10.
  • the individual annular courses which are accommodated in the portion of the mill 10 shown in FIG. 2 are designated e f e j ⁇ .
  • Reference characters e designate annular courses of plates which have inside surfaces 16 that are parallel to the axis of the mill.
  • the plates of the annular courses designated with the reference character f have inside surfaces 18 which are inclined at an angle of inclination B toward the interior or axis of the mill l0 and in the direction of flow, indicated by the arrow, of the material being ground.
  • the angle of inclination of the inside surfaces of these inclined plates depends upon the specific use of the mill, namely. the nature of the material being ground, etc., and to a certain degree also on the width of each plate. It has been found that it is generally desirable to select an angle [3 in the region of 5l 5 although good results may be obtained in special cases with different angles B up to and above 30. Alternatively, different inclinations may be selected in successive annular courses for some of them or groups of them compared to the inclination in preceding or succeeding annular courses f or groups thereof.
  • the width of each plate and of each annular course may vary; however, widths of, e.g., -250 millimeters have produced satisfactory results.
  • each annular course con sisting of one axial course e and one inclined course f may be combined and formed by a plate 20 which is bent so that its inside surface is axially oriented in part and inclined in part.
  • each combined annular course or unit E E is offset or angularly spaced relative to the succeeding and preceding annular courses by an angle a (see FIG. 1) whereas there is no offset within such combined annular courses or units.
  • the parting lines 22 betweeen each annular course e and the adjacent annular course fare represented by a thinner line than the parting lines 24 between successive units E,-E E -E etc.
  • the parting lines are represented in exaggerated width; they have actually only a width of 2-3 millimeters.
  • the thicker lines are intended to indicate that the annular courses on opposite sides of the respective parting line are offset or angularly spaced.
  • the extent offset will depend on the conditions, such as the material to be ground, the desired velocity of travel thereof through the mill, etc. Good results have been obtained with an offset (angle a) of l5-45 although this statement is not intended to impose a limitation on the selection of the offset.
  • the number and order of plates 15 having inside surfaces 16 which are not inclined but which are parallel to the axis of the mill and of plates 15 having inside surfaces l8 which are inclined toward the interior of the mill may be modified. For example, every third instead of every other course may be defined by inclined plates.
  • the length of annular courses e of plates having inside surfaces which are parallel to the axis of the mill and annular courses fof inclined plates can be varied as required so that units of longer annular courses e of axial plates and shorter annular courses fof inclined plates are installed in the shell 12 of the mill 10. It is particularly desirable if the mill has a square basic cross section with rounded corners and substantially straight sides.
  • At least every third annular course and preferably every other annular course (f, .f, is composed of plates 15 which have inside surfaces 18 which are inclined toward the interior of the mill l0 and in the direction of travel of the material being ground and the plates 15 are preferably so arranged that plates (e, e which have inside surfaces [6 which extend in the longitudinal direction of the mill and parallel to the axis of the mill alternate with the inclined plates (f, .f,
  • the annular courses e e, are mutually offset and the annular courses f .f are also mutually offset.
  • the mill 10 shown in FIG. 4 is composed solely of inclined platesf .f4; in other respects this embodiment is similar to the one shown in FIG. 2.
  • FIG. 1 illustrates the offset of annular courses 14 or units.
  • the inside contours of the first two units E and E of FIGS. 2 and 3 are shown; these are the inner edge contours of the inclined plates of the annular courses f and f
  • Different angles of offset a could be selected between successive annular courses e orfor units E over the length of the mill.
  • the variation of the local lead angle of the resulting helix defined at the beginning of the specification will be selected in view of the nature of the desired grinding operation and the desired distribution or sorting of the different sizes of grinding elements over the length of the mill.
  • the angle of inclination (angle B) of the inside surfaces 18 of the inclined plates may be "-30. preferably 5-l5.
  • the inclined surface of the inclined plates need not be flat but may be concavely curved. Besides, it is not necessary to use inherently inclined plates; the inclination may be provided by plates having inside surfaces extending parallel to the axis of the mill which are provided with protruding strips which extend at a desired angle other than 90 to the axis of the mill.
  • a tube mill having a length of 9 meters and 2.4 meters in diameter was fed with balls in sizes of 20-60 millimeters in the following proportions in percent by weight:
  • Each annular course 14 had a width of 250 millimeters.
  • Each pair of annular courses e, f were combined in a unit.
  • the first annular course of each unit was offset in the direction of rotation by an angle of l5 from the first annular course of the adjacent unit. Every other annular course had an inclination of 15.
  • the balls were fed as an unsorted mixture. The degree of fullness was 26 percent.
  • the mill was then operated for 24 hours at a speed of 0.7 times its critical speed so that a stationary equilibrium had then been obtained as regards the distribution of the balls.
  • the distribution in the mill length portions 0-1.5 meters. l.5-3.0 meters, 3.0-4.5 meters, 4.5-6.0 meters. 6.0-7.5 meters, 7.5-9.0 meters, in the direction of flow of the material was then examined with the following results:
  • Proportion Z by weight For a check. the direction of rotation was reversed in some tests so that the mill rotated counterclockwise. To cause the material being ground to flow in the same direction, the offset of the annular courses (in this case too every other course was offset in the counterclockwise direction of rotation) was changed. The ball mixture and the other conditions were entirely the tial degree.
  • a mill having a cylindrical shell and a plurality of liner plates mounted within said shell and forming the interior of the mill. said interior having a polygonal cross section formed of sides with rounded corners.
  • each grinding element being a Length portion 0 1.5 meters Ball diameter.
  • Length portion 3.0 4.5 meters Ball diameter. mm 20 25 30 4O Proportion, Z by weight 1.6 31.4 45.8
  • Length portion 6.0 meters Ball diameter. mm 20 25 3O 40 Proportion. i by weight 1.3 38.8 56.1 3.8
  • said interior formed solely by said liner plates which are arranged in a plurality of adjacent annular courses aligned one behind the other in the longitudinal direction of the shell. at least a portion of said annular courses being angularly displaced about the shell axis from the annular courses adjacent thereto, and at least some of said liner plates having inside surfaces being inclined toward the axis of the shell and in the direction of flow of the material to be ground.
  • every second said annular course is comprised solely of at least one liner plate having an inside surface inclined toward said axis of the shell and in the direction of the material flow.
  • a mill as defined in claim 1 wherein said inclined surfaces are formed by at least one strip protruding at an angle other than relative to said axis from the surface of said liner plates which are parallel to said axis.
  • a mill having a cylindrical shell having a plurality of liner plates mounted within said shell and forming the interior of the mill, said interior having a substantially square cross section with rounded corners. the radius of said corners being approximately one-third the length of each side of said square cross section, a plurality of grinding elements contained within said shell, the maximum dimension of each grinding element being a small fraction of the length of said side, said interior of the mill formed solely by said liner plates which are arranged in a plurality of adjacent annular courses aligned one behind the other in the longitudinal direction of the mill, each said annular course containing at least one said liner plate.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)
  • Gripping Jigs, Holding Jigs, And Positioning Jigs (AREA)
  • Breeding Of Plants And Reproduction By Means Of Culturing (AREA)
US406665A 1972-10-23 1973-10-15 Mill Expired - Lifetime US3880365A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT902372A AT319715B (de) 1972-10-23 1972-10-23 Mühle, insbesondere Rohr- oder Kugelmühle
AT635473A AT332199B (de) 1973-07-19 1973-07-19 Muhle, insbesondere rohr- oder kugelmuhle

Publications (1)

Publication Number Publication Date
US3880365A true US3880365A (en) 1975-04-29

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US406665A Expired - Lifetime US3880365A (en) 1972-10-23 1973-10-15 Mill

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US (1) US3880365A (da)
CH (1) CH570829A5 (da)
DE (2) DE7329229U (da)
DK (1) DK144584C (da)
ES (1) ES419408A1 (da)
FR (1) FR2208721B1 (da)
GB (1) GB1439414A (da)
IN (1) IN139175B (da)
IT (1) IT993125B (da)
MY (1) MY7800044A (da)
NL (1) NL7312957A (da)
PL (1) PL89480B1 (da)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4032075A (en) * 1976-08-16 1977-06-28 Tyer Sr Clarence C Multi-chambered scrubber having polygonal cross-section
US4194710A (en) * 1978-06-20 1980-03-25 Ebner Josef E Tumbling mill
US4211369A (en) * 1977-05-05 1980-07-08 Waagner-Biro Aktiengesellschaft Tumbling mills
US4485975A (en) * 1981-04-27 1984-12-04 Waagner-Biro Aktiengesellschaft Anchorage of the liner plates in tumbling mills by means of wedge-shaped elements
US4664324A (en) * 1985-08-14 1987-05-12 Magma Copper Company Grinding mill liner plate support
WO1988007411A1 (en) * 1987-03-26 1988-10-06 Belgorodsky Tekhnologichesky Institut Stroitelnykh Ball mill
US5472148A (en) * 1992-01-10 1995-12-05 Envirotech Pumpsystems, Inc. Grinding mill, lining and associated method of manufacture
CN100369675C (zh) * 2005-12-30 2008-02-20 中山大学 行星式球磨机用的球磨罐及带有该球磨罐的球磨机

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3677479A (en) * 1969-07-31 1972-07-18 Pierre Arsene Slegten Automatic grading linings for cylindrical tube or similar mills

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1125846A (fr) * 1954-06-30 1956-11-08 Smidth & Co As F L Broyeur à boulets
GB1299521A (en) * 1969-03-05 1972-12-13 Slegten Sa Improvements in or relating to mills

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3677479A (en) * 1969-07-31 1972-07-18 Pierre Arsene Slegten Automatic grading linings for cylindrical tube or similar mills

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4032075A (en) * 1976-08-16 1977-06-28 Tyer Sr Clarence C Multi-chambered scrubber having polygonal cross-section
US4211369A (en) * 1977-05-05 1980-07-08 Waagner-Biro Aktiengesellschaft Tumbling mills
US4194710A (en) * 1978-06-20 1980-03-25 Ebner Josef E Tumbling mill
US4485975A (en) * 1981-04-27 1984-12-04 Waagner-Biro Aktiengesellschaft Anchorage of the liner plates in tumbling mills by means of wedge-shaped elements
US4664324A (en) * 1985-08-14 1987-05-12 Magma Copper Company Grinding mill liner plate support
WO1988007411A1 (en) * 1987-03-26 1988-10-06 Belgorodsky Tekhnologichesky Institut Stroitelnykh Ball mill
US5472148A (en) * 1992-01-10 1995-12-05 Envirotech Pumpsystems, Inc. Grinding mill, lining and associated method of manufacture
CN100369675C (zh) * 2005-12-30 2008-02-20 中山大学 行星式球磨机用的球磨罐及带有该球磨罐的球磨机

Also Published As

Publication number Publication date
DK144584B (da) 1982-04-05
GB1439414A (en) 1976-06-16
IN139175B (da) 1976-05-15
PL89480B1 (en) 1976-11-30
DE7329229U (de) 1977-03-17
MY7800044A (en) 1978-12-31
IT993125B (it) 1975-09-30
ES419408A1 (es) 1976-04-01
CH570829A5 (da) 1975-12-31
FR2208721A1 (da) 1974-06-28
DK144584C (da) 1982-09-20
DE2340453A1 (de) 1974-05-02
FR2208721B1 (da) 1976-10-01
NL7312957A (da) 1974-04-25

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Free format text: RE-RECORD OF AN INSTRUMENT RECORDED 3/21/88, REEL 4840, FRAMES 688-690, TO CORRECT PATENT NUMBER 3,800,365 TO 3,880,365.;ASSIGNOR:FL AEROSPACE CORP.;REEL/FRAME:005194/0556

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