US962807A - Attrition-mill. - Google Patents

Description

E. P. ALSTED.

ATTRITION MILL.

APPLICATION FILED APR. 3,1909.

Patenfied June 28, 1910.

H7 TORNEYS.

UNITED STATES PATENT OFFICE.

EDWARD P. ALSTED, OF TRUESDELL, WISCONSIN.

ATTRITION-MILL.

I '0 all whom it may concern:

Be it known that I, EDWARD P. ALsTED, residing in Truesdell, in the county of Kenosha and State of Wisconsin, have invented new and useful Improvements in Attrition- Mills, of which the following is a description, reference being had to the accompanying drawings, which are a part of this specification.

This invention relates to improvements in attrition mills and more particularly to the form of mill in which the grinding is effected by means of two opposite disks rotating in opposite directions and provided on their working faces with opposing grinding plates not in contact with each other, the plates being provided with pockets and ribs whereby the grain fed between the plates is reduced by attrition.

One of the objects of this invention is to provide grinding disk plates for attrition mills in which the material being reduced between the plates is evenly distributed throughout the entire grinding surfaces of the plates thereby preventing the material from being moved centrifugally to the grinding surfaces near the outer periphery of the disk and causing uneven and eX- cessive wear of the grinding surfaces at this point.

Another object of this invention is to provide grinding disk plates for attrition mills in which the pockets or recesses formed in said plates are so positioned with relation to the pockets or recesses formed in the opposing disk that material may freely pass radially from one series of pockets to another series.

Vith the above, and other objects in view, the invention consists of the device and its parts and combinations, and all equivalents thereof.

In the accompanying drawing in which the same reference characters indicate the same parts in the several views; Figure 1 is a face view of a fragment of a grinding disk provided with the improved grinding plates; Fig. 2 is a face view on a reduced scale of the complete disk provided with the grind-' ing plates; Fig. 3 is a transverse section of one of the plates taken on line 33 of Fig. 1; and Fig. at is a diagrammatic view of one of the ribs of each opposing disk showing the line of engagement of the material re- Specification of Letters Patent. Patented Jung 28 1910,

Application filed April 3, 1909.

Serial No. 487,756.

ducing edges, one of the ribs being shown by dotted lines.

Referring to the drawing the numeral 5 indicates one of a plurality of segmental grinding plates which are adapted to be fastened to the opposing heads or disks of the attrition mill by means of screws 6 passing through openings provided in said plates and threaded to the disks. The segmental plates are provided with radial ribs 7 an outer concentric rib 8 and an inner segmental eccentric rib 9 forming recesses or pockets 10 in the plates. The inner concentric edges 11 of the plates are beveled off to more freely admit the material to be ground into the pockets between the plates attached to the opposing heads, and the radial ribs start or project from the fiat portion of the plates at and near the point where the beveled edge merges with said flat portion, each alternate radial rib being somewhat shorter than the adjacent radial ribs. While the ribs eX- tend in substantially radial lines from the axis of the disks the cutting or working edges 12 of the ribs extend in tangential lines of different angles from a small circle concentric with said axis.

The inner ends of the ribs are of a certain width indicated by the numeral 13 and the side edges of the ribs gradually converge toward each other to a point 14. From this point the sides edges of the ribs gradually diverge to a point where the rib merges with the inner segmental eccentric rib 9. From the outer edge of the segmental eccentric rib the edges of the radial ribs, reduced in width extend in diverging lines to the concentric rib 8 and merges therewith thus providing cutting edges, which, when the two opposing disks rotating in opposite directions are reducing the material fed therebetween the outer portions of the cutting edges forming the outer pockets will engage the material in said outer pockets first and the line of engagement will travel, as the rotation continues, toward the inner eccentric rib, and the material within the inner line of pockets will be engaged by the opposite end portions of the ribs forming said pockets and the line of engagement will travel toward the portions of the ribs which are reduced in width and as indicated by the numeral 14, thus providing for the even wear of the cutting edges of the plates. It is of course understood that the material being reduced between the attrition faces of the plates is fed to said plates from the inner portion thereof, and is moved outwardly therefrom by centrifugal force.

It will be noticed that the inner rib of each segmental plate extends in a curve of larger diameter than the curve of the plate, or in other words the rib is eccentric to the path of travel of the segment, and when the plates are assembled on the disks or heads of the attrition mill the ends of the eccentric ribs meet and form a hexagonal shaped rib with corners l5 and curved sides 16. The hexagon shaped rib is positioned concentric to the axis of the disks, and when the plates of opposing disks are rotated the corners of the hexagonal ribs will overlap the curved sides of the ribs of the opposite plates and open communication between the inner and the outer series of pockets so that material being reduced therebetween may pass from the inner to the outer pockets. The hex agonal ribs of the opposing plates also serve to assist in reducing the material. As the corners pass the curved sides they form a cutting edge similar to the radial ribs.

Both side edges of the radial ribs are similar in shape so that when the edges on one side are worn the disks may be rotated in the opposite direction and the same results obtained.

From the foregoing description it will be seen that provision is made for spreading the wear of the cutting or reducing edges of the grinding plates throughout the entire plate and thus eliminating excessive wear at one point of each reducing edge.

lVhat I claim as my invent-ion is:

1. An attrition mill, comprising opposite rotatable plates provided with material reducing ribs, the material engaging edges of ribs of opposite plates diverging toward the axis of the plates when in engagement with each other to advance the line of ma terial of said edges in a direction toward the axis of rotation, and segmentally curved ribs provided on said plates, the segmental curvatures of which are eccentric to the axis of rotation.

2. An attrition mill, comprising opposite rotatable plates provided with material reducing ribs, the material engaging edges of ribs of opposite plates diverging toward the axis of the plates when in engagement with each other to advance the line of material engagement of said edges in a direction toward the axis of rotation, ribs concentric to the axis of rotation connected to the outer ends of said ribs, and segmentally curved ribs provided on said plates, the segmental curvatures of Which are eccentric to the axis of rotation.

3. A grinding plate for attrition mills, comprising a segmental plate provided with radial ribs, the material engaging edges of adjacent ribs diverging from each other toward their inner ends, and a transverse rib formed on said plate and extending in a line eccentric to the axis of said plate.

4. A grinding plate for attrition mills, comprising a segmental plate provided with radial ribs, the material reducing edges of adjacent ribs diverging from each other for a portion of their lengths then converge toward each other for a certain distance and then again converging toward each other toward their outer ends, and a rib extending transversely across the radial ribs in a line eccentric to the axis of said plate.

5. A grinding plate for attrition mills, comprising a segmental plate provided with radial ribs, the material reducing edges of adjacent ribs diverging from each other for a portion of their lengths then converging toward each other for a certain distance and then again converging toward each other toward their outer ends, a rib extending transversely across the radial ribs in a line eccentric to the axis of said plate, and an outer annular rib extending in a line concentric to the axis of said plate.

6. An attrition mill, comprising opposite rotatable plates provided with material engaging ribs forming pockets, the edges of adjacent ribs diverging toward the axis of rotation of the plates, and annular ribs formed on said plates and provided with a plurality of segmental sides which are positioned to overlap portions of the annular rib of the opposite plate and permit material to pass radially from one pocket to another pocket.

7. A grinding plate for attrition mills, comprising a segmental plate having an inner beveled edge and provided with radial ribs, the material engaging edges of ad j acent ribs converging toward each other toward their outer ends, and a transverse rib formed on said plate and extending in a line eccentric to the axis of said plate.

In testimony whereof, I aflix my signature, in presence of two witnesses.

EDXVARD P. ALSTED.

/Vitnesses:

R. S. G. CALDWELL, ALMA A. KLUG.

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