US1295290A - Tube-mill. - Google Patents

Description

1. s. FIASTING.

TUBE MILL.

APPLICATION FILED AUG-31, I9l6.

Patented Feb. 25, 1919.

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' ATT$RNEL$ To all whom it may concern:

JOHA'N s. FASTING, 0E FREDERIKSBERG, NEAR coPENHnoEN, DENMARK, ASSIGNOB T0 F. L. smmm & 00., or NEw YORK, N. Y., A CORPORATION or NEW JERSEY.

T BE-MILE.

Specification of Letters Patent.

' Application filed August 81, 1916. Serial No. 117,854.

Be it known-that I, JoHAN S. FASTING, a subject of the King of Denmark, residing at Frederiksberg, near Copenhagen, Denmark, have invented certain new and useful Improvements in Tube-Mills, of which the following is a specification, reference being had to the accompanying drawings, forming a part hereof.

In Letters Patent of the United States No. 1,204,554, dated November 14, 1916, there is shown and described an improved method in the art of grinding with free grinding bodies which consists in producing in the mill a slowly rotating mass of grinding bodies and material to be ground and applying closely-related frictional lifting ribshaving surfaces extending in the direction of rotation to said mass while rotating. As suggested in the specification of said patent, the closely related lifting surfaces might have their gripping action accentuated by roughening the faces of the lifting ribs so as to increase the friction between the ribs and, the material. The present application is concerned with a grinding mill provided with frictional lifting ribs of the general character claimed in said patent and seeks to cover, specifically, lifting ribs having roughened or corrugated faces or steps on such faces for the purpose of afl'ordin positive support to a substantial portion 0 the mass between adjacent ribs and thereby increase the lifting effect of the ribs partially by such positive support and partially by the increased frictional drag of the faces on the charge. In practising the invention, the charge is separated into parallel, circumferential streams by the annular partitions and each stream is wedged between roximate ribs so that the charge therein will be carried up the wall of the mill partially by the positive lifting action of the irregular faces of the ribs and partially by the lateral support afforded by the frictional engagement of the charge with the ribs. In accordance with the present invention the annular partitions may be formed in a number of difierent ways but aiford,.in each embodiment,

partition constructed in accordance with the invention.

Figs. 48 are fragmentary detail views in sectlon taken through ribs having roughened lifting surfaces in accordance with this invention and adaptable for use in any one of the mills shown in Figs. 1-3.

As pointed out in the preamble, the lIl lproved method of grinding set forth in the patent referred to consists in applying closely related frictional liftin partitions on the inner wall of a mill, where y upon rotation of the mill these partitionswill separate the charge into parallel circumferential streams and thereby add lateral support to the lifting action of the centrifugal force de rived from rotation of the mill. The present invention contemplates the employment of the same method of grinding with free grinding bodies in that the charge is broken up into parallel, circumferential streams by closely related annular partitions and support is given to each of these streams by the partitions in order to supplement the lifting action of centrifugal force derived from rota- ;tionof the mill.

In accordance with the present invention,however, mere lateral support of the streams, such as would be derived from impressin frictional lifting surfaces on the sides 0 the streams, is not reliedupon entirely, but the surfaces of the annular partitions or ribs are formed of such cross-sectional contour as to afford, to an appreciable degree, a positive support for a substantial portion of the charge within the streams. The provision of such irregularly formed surfaces on the annularpartitions or ribs also insures a marked increase in the 10.5 wedging action on the charge in each stream and a corresponding increase in the lateral support afforded to the charge through this wedging action. Iteis to be noted that whereverthe term partition is employed in the specification and claims, it is intended to cover any elements, whether integral or sectional, whereby a dividing or partitioning action is effected.

Referring now to the embodiments shown .in the accompanying drawings, which will serve to emphasize some of the forms of the present invention, it will be seen that in ig. 1, there is secured to the'inner wall of the mill a, a partition b made up of a serles of ribs or flanges 0 which are secured to the inner wall of the mill and are spaced from- In Fig. 2 it will be seen that the partition B is made up as a single integral annular rib C of smaller diameter than the inner diameter of the mill and this rib is secured in place by lugs or feet e interposed between the rib and the wall of the mill at suitable intervals around the periphery of the rib. By mounting the rib C in the 85 'there is an annular space D left between the rib and the lining of the mill for free longitudinal movement of the material through the mill.

Still another form of partition E is shown in Fig. 3. This partition, like that shown in Fig. 2, is formed as an unbroken annular rib C of smaller diameter than the inner diameter of the mill. This integral .et rib is supported on a suitable spider f, the

radial arms of which are carried on a hub g keyed on-a suitable supporting shaft h which may be mounted coaxially with the mill and extend th'erethrough. In this embodiment the parts are so dimensioned as to leave an annular space D between the inner lining of the mill and the outer periphery of'the rib C" which space is of the same general character as the space D shown in Flg. 2 and permits free longitudinal movement of the material through the mill.

Thus far it has been sought only to discuss three of the many forms which the partitions embodying the invention may as- 60 sume, in an endeavor to emphasize that the invention is not to be limited to the particular means for forming these partitions or of mounting them in the mill so as to perform their intended functions and yet permit free longitudinal movement of the material manner described, it will be evident that.

through the mill. The invention, however, is primarily concerned with the specific character of the ribs employed in the formation of these partitions since the character of the .partitions themselves differs in no wise'in this application from that contemplated in the original case.

In Figs. 48 there are illustrated in section, by way of example, fivedifi'erent forms of llbS which embody the present invention and may be employed in the partitions shown in Figs. 1-3. The characteristic feature of-th'ese ribs resides in the provision of radial shelves which shall afford a positive lifting action for an appreciable part of the mass inthe circumferential streams and incidentally increase appreciably the lateral support given by the frictional drag impressed on the mass by the rib. The rib is shown in Fig. 4 has annular 'groovesor 86 corrugations it formed on its opposite faces, these grooves being of such shape as to give positive support to. the material restin in the grooves and impress on thev mass a rictional drag which shall serve to insure a 90 wedging action suflicient to carry the charge part way up the wall of the mill and to a point beyond where centrifugal force alone would carry it. The shape of the grooves, however, it'will be noted, is such as to perinit the charge to fall from the face of the rib immediately upon the breaking down of the aforementioned Wedge or arch.

In principle, and general cross-sectional appearance, the construction and operation of the ribs Z, on and 11. shown in Figs. 5-7, respectively, are very similar to the construction and action of the rib shown in Fig. 4. These ribs are grooved on their opposite faces to permit the charge to enter and be given appreciable positive support and be subjected to an increased gripping action for the substantial lateral support desirable for the successful practice of the method.

The rib-0 shown in Fig. 8, while of somewhat difl'erent contour, is intended to function in the manner described in connection with the other ribs shown in the drawings. This rib is corrugated and its grooves instead of being angular in cross-sectional outline are curved.

It will be understood that the positive support afforded by the ri-bsin accordance wit the improvements may be varied through wide ranges by changing the crosssectional contour of the grooves between one which is most abrupt and angular, such as is suggested in Figs. 6 and 7 to one with gently rounded grooves of the character suggested in Fig. 8.

As pointed out hereinbefore, the partitions in Figs. 1, 2 and 3 may be made up either with unbroken ribs spaced from the wall of the mill or may be formed with a circumferential series of short arcuate ribs 130 (as in Fig. l) the primary functions of the partitions being preserved in either case and free longitudinal movement of the material.

through the mill being provided for. The partition itself may be formed of an unbroken rib or ribs of the character described in connection with the several embodiments shownin Figs. 48, the supplemental posiing a peripheral lining and a diametric partition with its periphery adjacent said lining and having its opposite side forming radially extending shelves.

2. A tube mill conslsting of a drum having therein a diametrical partition Witha central opening, said partition formed of imperforate sections each of which has radial grooves in its opposite sides opening longitudinally of the drum.

This specification signed this 9th day of May, A. D. 1916. JOHAN' s. FASTING.

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