US3380670A - Rotating grinders - Google Patents

Rotating grinders Download PDF

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Publication number
US3380670A
US3380670A US384738A US38473864A US3380670A US 3380670 A US3380670 A US 3380670A US 384738 A US384738 A US 384738A US 38473864 A US38473864 A US 38473864A US 3380670 A US3380670 A US 3380670A
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United States
Prior art keywords
cylinder
bars
product
pockets
grinding
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US384738A
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English (en)
Inventor
Beudin Leonel Louis J Baptiste
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.)
Bureau de Recherches Geologiques et Minieres BRGM
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Bureau de Recherches Geologiques et Minieres BRGM
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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
    • 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
    • B02C17/02—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 with perforated container
    • 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
    • B02C17/04—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 with unperforated container
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B31/00—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor
    • B24B31/02—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor involving rotary barrels

Definitions

  • the invention is concerned with a rotating grinder comprising a drum inside which are provided grinding bars resting upon the inner wall of said drum.
  • the wall of the drum is provided with passages of a radial depth at least equal to the maximum dimension of the grains of material to be ground, the length of the passage in the direction of the drum being smaller than the axial length of the drum.
  • Said passages communicate freely with the inside of the drum but at their outer ends they are provided with screens to prevent the outflow of the material grains not yet ground.
  • This invention relates to grinders and more particularly to rotating grinders utilizing a hollow cylinder.
  • the present invention is directed to grinders of the type comprising a rotatable cylinder having a substantially horizontal axis and containing freely rotatable bodies adapted to crush, between themselves and the interior longitudinal wall of said cylinder, products introduced into the latter.
  • This invention is particularly directed to grinders of this type in which the freely rotatable bodies are in the shape of cylindrical bars; but this is only because such a shape seems to have the most valuable applications at present and it should not be treated as limiting the scope of the present invention.
  • the embodiments of the present invention involve, principally, the provision, in the longitudinal cylinder wall, of pockets having a depth which is at least equal to the maximum size of the particles which are to undergo the grinding operation or, when the grinding bodies are spherical, the depth preferably being equal to this maximum size plus the depth to which these grinding bodies can penetrate into the pockets, with the result that when these particles rest in the pockets, they can not be crushed or packed down, but will be carried along and later released by the pockets at a point where they will fall ahead (in the sense of the direction of rotation of the grinding bodies) of at least some of said bodies.
  • the present invention also involves several secondary features which are preferably used together with the principal structure described above and which will be described in greater detail below.
  • the present invention is directed toward certain modes of application and of construction of the above-described structure and more particularly to grinding devices employing the above-mentioned features, as well as toward elements and tools required for their construction.
  • FIG. 1 shows a side view of a bar-type grinder representing a preferred embodiment of the present invention
  • FIG. 2 is a partly cut-away end view of the right end of the device of FIG. 1;
  • FIG. 3 is an end view of the left end of the device of FIG. 1;
  • FIG. 4 shows a partial end view, similar to the view of FIG. 2, showing, for purposes of comparison, a bartype grinder according to the prior art.
  • FIG. 1 shows an overall view of a grinder assembly constructed according to the present invention and com prising a hollow rotatable cylinder I intended to receive the material to be ground and containing a plurality of bars capable of freely rolling along the inner cylindrical surface of member 1, the dimensions of the cylinder and the bars, as well as the number of bars and the weight of each, being determined according to the nature of the product treated and desired output rate for the assembly.
  • Cylinder 1 is supported upon two pairs of friction rollers 3 and 4 so that its axis XX is substantially horizontal, each pair of rollers being mounted on a respective axle 5 which is parallel to the cylinder axis, and the two axles 5 being symmetrically disposed on opposite sides of said cylinder axis.
  • the rollers 3 are driven, through the intermediary of their common axle 5 and a speed reducer 6, by a motor 7.
  • Rollers 4 can be freely mounted on their axle 5.
  • rollers 3 being in the same plane perpendicular to the cylinder axis as a respective roller 4, the rollers can be disposed to a pair of circumferential grooves 8 on the outer cylindrical surface of cylinder 1 in order to prevent any displacement of the cylinder along its axis.
  • the rollers 3 could, like the rollers 4, be mounted for free rotation with respect to their axle 5 and the cylinder 1 could be rotated by a toothed ring gear rigidly mounted to said cylinder, and coaxial therewith, and engaged by a pinion driven by motor 7.
  • cylinder 1 instead of being mounted on rollers 3 and 4, cylinder 1 could be mounted on a coaxial shaft supported by suitable bearings and driven, through a speed reducer, by motor 7.
  • means are provided for permitting the loading of the cylinder with material to be ground.
  • Such means could consist of a door 9 constituting one of the bases of cylinder 1, for permitting a discontinuous loading, or they could consist of a small chute, for example, or similar arrangement for permitting the continuous introduction of material through an opening arranged in one of the bases.
  • the other base of cylinder 1 is designated as 13 in FIGS. 1 and 3.
  • FIG. 4 shows a segment of such prior device in which the interior longitudinal wall 10b of cylinder 10 is completely even and cylindrical with the result that the bars 2 are in contact with this surface over their entire length.
  • the product undergoing grinding accumulates behind the bars 2, taken in the sense of the relative movement of the bars along the surface 10b, which relative movement is in the opposite direction from arrow F.
  • These conditions produce the results, on the one hand, of removing from the grinding operation the product accumulated in region A, behind the zone of action of bars 2, and, on the other hand, of substantially preventing at least the first bar (to the right of FIG. 4) from participating in the grinding operation, since it only encounters a very small quantity of the product (region B).
  • the present invention seeks to remedy the first shortcoming noted above by the provision of pockets 14 in the longitudinal cylinder wall 10.
  • the depth a of these pockets, with respect to surface a is at least equal to the maximum size (diameter) of the grains of the product to be ground. It should be appreciated that the relative magnitude of dimension a is exaggerated in FIG. 2 for purposes of illustration.
  • This depth for the pockets permits them to carry some of the product along with them and to later release the product so that it will fall ahead of at least some of the bars, as is indicated in FIG. 2. Some of the product will also fall on the bars and will be carried by their rotation, to their front. It should, of course, be appreciated that the width b of these pockets, taken in the sense of the circumference of the cylinder, must be at least as great as the depth a. Because of the depth of these pockets, the grinding operation is eifectuated only along the cylindrical surface 10a, and not in pockets 14, so that the grains of the product will not be packed down in these pockets and can thus easily fall out of them when the pockets have rotated far enough to begin to tilt, as is indicated schematically in FIG. 2.
  • the prior art devices present another drawback in that the ground products remain in the grinder until the end of the grinding operation, at which time the cylinder is stopped and all of the product is taken out at one time by way of a door 9, for example. In general, such a procedure produces an over-grinding which is often undesirable.
  • the present invention contemplates the provision, at the base of each pocket 14, of a plurality of outlet holes for the ground product. These holes are preferably constituted by the passages in each screen or grating 11 placed in the openings 12 formed in wall 10, the pockets 14 being thus defined by the edges of opening 12 and by gratings 11.
  • These openings 12 are desirably distributed in one of several echelons along the length of wall 10 in such a way that at least one opening 12 will be cut by any plane through the cylinder, perpendicular to the cylinder axis.
  • the number of pockets 14 is determined experimentally according to the nature of the product to be ground, and the dimensions of the passages in gratings 11 are determined according to the final desired product grain size.
  • the ratio between the surface area of longtudinal wall 10 and the total surface area of openings 12 is determined experimentally according to the characteristics of the apparatus, e.g. ratio of cylinder length to diameter, rotating speed, and the nature of the product to be ground.
  • the gratings 11 could be held, by means of screws or similar means, between a flange '15 and the outer cylinder wall, and a shim or wedge 16 may, if desired, be interposed between the grating and the cylinder wall.
  • the wedge 16 and flange each have an opening formed therein which conforms to the shape of opening 12 and which is aligned therewith.
  • a should be at least equal to the sum of this penetration depth and the maximum grain size of the product to be ground.
  • Cylinder comprising 32 rectangular openings, mm. longx25 mm. wide, furnished with metallic screens.
  • EXAMPLE 2 Cylinder similar to that of Example 1, with the exception that the surface contains 32 pockets, 160 mm. long x 25 mm. wide x 5 mm. deep, furnished with solid bottoms.
  • EXAMPLE 3 Sheet metal cylinder having a thickness of 1 mm. and having its cylindrical surface pierced by 'a series of round holes.
  • Example 4 In the test, the device of Example 4 was rotated at a speed of 20 to 30 r.p.m., this being the speed range used for each test. It was noted that the product in this grinder is dragged along by the rotating cylinder wall through an angle of about 100, with respect to a vertical plane through the cylinder axis, and then falls back into the region behind the bars (region A of FIG. 4), thus escaping the region of maximum grinding action and, in particular, the region of action of the first two bars.
  • Example 2 The device of Example 2 was rotated at the same speed as the above device.
  • the ground product was carried along by the pocket through an angle of and then fell ahead of the bars, with the result that all of the bars played an active role in the grinding operation.
  • Example 1 For this second series of tests, the cylinder of Example 1 was compared with that of Example 4.
  • the metallic screens were made of wires having a diameter of 0.4 mm. and the space between wires was 0.99 mm.
  • the screen covered openings serve to reduce the time of grinder operation to one-fourth of that required when no openings are present.
  • Example 3 For the third series of tests, the arrangement of Example 3 was compared with that of Example 1.
  • Example 3 is roughly as inefiicient of the solid cylinder, despite the fact that the perforated cylinder has a larger total perforation area than does the cylinder of Example 1.
  • An improved grinder for grinding solid, particulated material which comprises,
  • openings and said passages starting therefrom are elongated in the axial direction of the drum and of a length in said direction equal to only a por tion of the axial length of said drum, the width of said openings and passages and the depth of said passages being greater than the maximum dimension of the particles of said material,
  • said grinding elements are constituted by cylindrical bars of a length of the same order of magnitude as the inner axial length of said drum, whereby said bars cannot project outwardly into said passages beyond the inner wall of said drum, and in the provision of a perforated wall covering the outer end of each of said passages.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Crushing And Grinding (AREA)
US384738A 1963-07-25 1964-07-23 Rotating grinders Expired - Lifetime US3380670A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR942697A FR1371355A (fr) 1963-07-25 1963-07-25 Perfectionnements apportés aux broyeurs rotatifs à corps libres roulants, plus particulièrement aux broyeurs à barres

Publications (1)

Publication Number Publication Date
US3380670A true US3380670A (en) 1968-04-30

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US384738A Expired - Lifetime US3380670A (en) 1963-07-25 1964-07-23 Rotating grinders

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US (1) US3380670A (enExample)
BE (1) BE650477A (enExample)
DE (1) DE1287913B (enExample)
FR (1) FR1371355A (enExample)
GB (1) GB1025219A (enExample)
NL (1) NL6408546A (enExample)
OA (1) OA00121A (enExample)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3811624A (en) * 1971-09-29 1974-05-21 Fives Lille Cail Rotary tubular crusher
JPS5224379A (en) * 1975-08-20 1977-02-23 Otsuka Tekko Kk Simultaneous production process of two or several kinds of articles in circumferential discharge ero-fgall mill
CN105643422A (zh) * 2016-01-30 2016-06-08 天津市巨星祥海机械有限公司 一种新型金刚砂磨光装置
USD940763S1 (en) * 2021-04-12 2022-01-11 Yuan Zhao Rock tumbler
USD973732S1 (en) * 2022-08-23 2022-12-27 Huimin Zou Rock tumbler
USD975147S1 (en) * 2021-12-08 2023-01-10 Yuan Zhao Rock tumbler
USD982626S1 (en) * 2021-08-11 2023-04-04 Idea Vault Holdings, Inc. Tumbler
USD1004644S1 (en) * 2022-08-30 2023-11-14 Yongxiu Liu Rock tumbler

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4603814A (en) * 1985-03-15 1986-08-05 Inco Alloys International, Inc. System for discharging rotary mills

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1516467A (en) * 1924-01-07 1924-11-18 Herman John Screening ball mill
US1539237A (en) * 1924-02-11 1925-05-26 John Herman Screening ball mill

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1516467A (en) * 1924-01-07 1924-11-18 Herman John Screening ball mill
US1539237A (en) * 1924-02-11 1925-05-26 John Herman Screening ball mill

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3811624A (en) * 1971-09-29 1974-05-21 Fives Lille Cail Rotary tubular crusher
JPS5224379A (en) * 1975-08-20 1977-02-23 Otsuka Tekko Kk Simultaneous production process of two or several kinds of articles in circumferential discharge ero-fgall mill
CN105643422A (zh) * 2016-01-30 2016-06-08 天津市巨星祥海机械有限公司 一种新型金刚砂磨光装置
USD940763S1 (en) * 2021-04-12 2022-01-11 Yuan Zhao Rock tumbler
USD982626S1 (en) * 2021-08-11 2023-04-04 Idea Vault Holdings, Inc. Tumbler
USD975147S1 (en) * 2021-12-08 2023-01-10 Yuan Zhao Rock tumbler
USD973732S1 (en) * 2022-08-23 2022-12-27 Huimin Zou Rock tumbler
USD1004644S1 (en) * 2022-08-30 2023-11-14 Yongxiu Liu Rock tumbler

Also Published As

Publication number Publication date
NL6408546A (enExample) 1965-01-26
GB1025219A (en) 1966-04-06
FR1371355A (fr) 1964-09-04
DE1287913B (enExample)
OA00121A (fr) 1966-01-15
BE650477A (enExample) 1964-11-03

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