US3045933A

US3045933A - Milling apparatus

Info

Publication number: US3045933A
Application number: US77397A
Authority: US
Inventors: Mino Alfonso Di
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1960-12-21
Filing date: 1960-12-21
Publication date: 1962-07-24
Anticipated expiration: 1979-07-24

Description

July 24, 1962 A. DI MINO MILLING APPARATUS Filed Deo. 21, 1960 FLUD CONTROL :'PUMP UPPLY" MEANS 58 -r T T* INVENTOR. A LFoNso DlMlNo @iQ/M ATTORNEY United States Patent Oce 3,345,933 Patented July 24, 1962 3,045,933 MHJLING APPARATUS Alfonso Di Mino, Woodcliff Lake, NJ., assignor to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Filed Dec. 21, 1960, Ser. No. 77,397 7 Claims. (Cl. 241--111) This invention relates to milling apparatus for use in pulverizing materials such as oils, paints, pigments and all types of mineral, vegetable, and animal substances.

Milling apparatus of the type contemplated by the present invention includes those types of mills known as ball mills, roll mills, and colloidal mills. Each of these types of mills has is own particular characteristics and utility. However, there is no commercially available milling apparatus which includes, in one structure, means for performing the functions of two or all of these types of mills. Such apparatus is made available by the present invention in a comparatively simple and inexpensive structure which has all of the advantages of these separate types of mills.

The principles `and objects of the invention are directed toward the provision of improved milling apparatus which combines in a single structure means for performing several dilferent types of milling operations.

Briefly, milling apparatus embodying the invention includes a housing in which a central roll is loosely and rotatably mounted. Adjacent to and surrounding this central roll `are a plurality of driven rolls positioned in operative relation with the central roll. The space between the driven rolls and the wall of the housing is sulliciently small to achieve milling action between these rolls and the wall of the housing. A plurality of hollow tubes are rigidly supported within the housing and thus lend strength and rigidity thereto. Since the tubes are hollow, they are also readily adapted for use in circulating a cooling or heating fluid through the housing whereby the temperature of material being milled may be controlled.

The mill provides roll mill action between each driven roll and the central roll, and both ball mill and colloidal mill action in the space between the driven rolls and the wall of the housing.

The invention is described in greater detail by reference to the drawing wherein:

FIG. 1 is an elevational view, partly in section, of the apparatus of the invention;

FIG. 2 is a view looking into one end of the apparatus, and

FIG. 3 is asectional view along the line 3-3 in FIG. l.

Referring to the drawing, milling apparatus embodying the invention includes a `hollow cylindrical housing 12 comprising a side wall 13 and end walls 14 and 16 in fluid-tight engagement therewith. The end walls are adapted to be removed from `the side wall, if desired. The side wall 13 is` provided with a filling aperture 18 having a cap 2l) through which the housing is lilled, and a suitable gas pressure relief valve 22. A material discharge port 24 is provided in one of the end walls 14 or 16.

The mill 10 includes a first central cylindrical roll 26 positioned on the axis of the housing. The central roll is made of steel or the like and may have a smooth, grooved, or rough external surface as required. The central roll is loosely mounted on a shaft 28 which is oriented on the horizontal axis of the housing 12 `and which is rotatably mounted in suitable bearing surfaces in the end walls 14 and 16. The shaft 28 extends a suitable distance beyond one of the end walls, for example end wall 14, and carries a gear 29 and a pulley 30. r[The pulley 30 is coupled to a Suitable power source such as a motor 31.

A plurality of peripheral rolls 32, 34, 36 are mounted within the housing surrounding and in operative relation with the central roll 26. The peripheral rolls are spaced equidistantly from each other about the central roll. The peripheral rolls are made of steel or some other suitable material, and have smooth, grooved, or rough external surfaces. The peripheral rolls 32, 34, and 36 are secured to `and rotated by shafts 37, 33, and 39, respectively, which are suitably rotatably journalled in the end walls 14 and 16. Shafts 37, 38, and 39 extend through the wall 14 and terminate outside the housing where they carry gears 4t), 42, and 44, each of which meshes with gear 29 on shaft 28.

According to one aspect of the invention, a minimum spacing 45 is provided between the side wall 13 of the housing and the adjacent peripheral rolls 32, 34, and 36. With such a mechanical arrangement and with relatively high speed rotation of the peripheral rolls, milling action is achieved in the space between these rolls and the wall of the housing due to turbulence and friction. Thus, the spacing 45 is designed to provide optimum milling action with the selected roll speed of rotation. This spacing is as small as possible and, preferably, only a fraction of an inch. A spacing in the range of about 1/15 to J/32 of an inch is satisfactory.

The mill 1t) includes a plurality of rigid spacer members 46, 43, and Sti secured within the housing 12 between the end walls 14 `and 16. The spacers are preferably made of steel or some similar material and are hollow so that a lluid may be circulated through them for regulating the temperature of the material inside the housing. The spacers are each provided with a pair of hollow threaded end pipes 46', 43 and 50', respectively, which extend through the walls 14 and 16 `of the housing. Outside the housing, nuts 52 or other suitable fasteners are secured to the threaded pipes to hold the spacers securely in position. In addition, a iirst hollow annular fluid-circulating pipe 54 is secured by suitable iluidtight littings *55 to one set of end pipes adjacent to the end wall 14, and a similar fluid-circulating pipe 56 is `secured by fittings 57 to the other set of end pipes adjacent to the other end wall 16. The pipes are suitably coupled to a iluid supply 58 and pumping means 60 for circulating the lluid through the spacers 46, 48, `and 50. Suitable means 61 are also included in the fluid supply system for regulating the temperature of the circulating duid.

In `operation of the invention, the housing 12 is lled with raw material to be milled, the material being admitted through the opening 18 in the wall 13. Power is applied through the pulley Sti and the gears 29, 40, 42, and 44, and the peripheral rolls 32, 34 and 36 are rotated thereby. As these rolls rotate, the material contained within the housing passes between them and the central, loosely held roll 26 and the central roll is caused to rotate due to the frictional forces developed. As the parts continue to rotate with respect to each other and the material passes between the peripheral rolls and the central roll, the desired milling operation is achieved. This action of the apparatus of the invention comprises, in effect, roll mill action. In addition, as the peripheral rollers rotate, material which lies between the rollers and the side wall is milled by ball mill action as the particles abrade each other. The ball milling effect may be enhanced by intermittently reversing the direction of rotation of the mill rolls. A third effect, colloidal milling, is achieved as the material being milled is driven against the inner `surface of the side wall of the housing due to turbulence developed by the rotating rolls. The milling operation is aided by the temperature control efected by the tluid which may be circulated through spacers 46, 48, and Sil.

What is claimed is:

1. Milling apparatus including a housing, a central roll in said housing and freely rotatable on a shaft, and a plurality of rolls surrounding and in operati-ve relation with `said central roll, each of said plurality of rolls being adapted to be positively driven, the space between said driven rolls and the wall of said housing being small so that, as said positively driven rolls rotate, considerable turbulence is developed in said space and the milling action is aided by said turbulence.

2. Milling apparatus including a housing, a central roll in said housing and freely rotatable on a shaft, a plurality of rolls surrounding and in operative relation with said central roll, each of said plurality of rolls being adapted to be positively driven, the space between said driven rolls and the wall of said housing being of the order of a fraction of an inch so that, yas said positively driven rolls rotate, considerable turbulence is developed in said space and the milling action is aided by said turbulence, and means within said housing for circulating a temperaturecontrolling uid therethrough.

3. Milling apparatus including a housing, a central roll in said housing and freely rotatable on a shaft, a plurality of rolls surrounding and in operative relation with said central roll, each of said plurality of rolls being adapted to be positively driven, the space between said driven rolls 4and `the wall of said housing being small so that, as said positively driven rolls rotate, considerable turbulence is developed in said space and the milling action is aided by said turbulence, and a plurality of hollow spacers within said housing and having means for circulating a temperature-controlling iiuid therethrough.

4. Milling apparatus including a housing, a central roll in said housing and freely rotatable on a shaft, and a plurality of roll-s surrounding and in operative relation With said central roll, each of said plurality of rolls being adapted to be positively driven, said driven rolls being adapted to drive said centrai roll through the material being milled `as it passes between them, the space between said driven rolls and the wall of `said housing being small so that, as said positively driven rolls rotate, considerable turbulence is developed in said space and the milling action is aided by said turbulence.

5. The mill dened in claim 4 and including means within said housing for circulating a temperature-regulating fluid therethrough.

6. The mill defined in claim 4 and including a plurality of hollow cylinders iiXed in position inside said housing and adapted to have a temperature-regulating fluid circulated therethrough whereby the temperature of the material being milled is regulated.

7. The milling apparatus defined in claim 4 wherein said housing includes two end walls, and a plurality of hollow cylinders are xed in position between said end walls, said cylinders being adapted to have va temperatureregulating lfluid circulated therethrough whereby the temperature of the material being milled is regulated.

References Cited in the tile of this patent UNITED STATES PATENTS