US1777605A - Mill - Google Patents

Description

Oct. 7, 1930. E. H. DIMLER 4 1,777,605

' HILL Fil ed Aug. 10. 1927 Patented Oct. 7, 1930 UNITED STATES PA OFFICE ERNEST DIMLER, or BETHLEHEM, rENNsYLvANIA, ASSIGNOR "r BETHLEHEM FOUNDRY & MACHINE COMPANY, or BETHLEHEM, PENNSYLVANIA, A CORPORA- 'llION OF PENN SYLVANIA,

MI-LL.

Application filed August 1927. Serial No. 212,107.

The-present invention relates to mills and particularly to crushing or pulverizing mills:

Manytypes of mills for pulverizing lump and granular material have heretofore been designed and suggested and many are now on" the'markehjsuch for instance as mills for grinding or pulverizing slag and mills for grinding cementclinker. Materials of this class are sometimes very hard and sh arp, and

the operation of crushing and reducing them of the'material being acted upon, with the *inalcontour, becoming pittedas the softer portions of the metal, or those portions which are most Sub ected to wear, wear away at a faster rate than the harder portions, and eventually reach such a state of surface unevennessthat unlformlty of product can no longer 0' be realized. Furthermore, there is a greatf reduction lnthe. quantity of material which can be pulverized in a given time. It is then necessary to remove the worn crushing ele ments and to replacethem with new ones,

thus involving a considerable loss, not only because of the material and labor cost in volved, but also because of tlie break in output due to the shut down. Particularly have the operators of cement clinker pulverizing mills been inconvenienced by the rapid wearing away of the crushing elements, Such mills" are generally deslgned and intended for 'con-. tlnuous day and night-operation, a steady stream of hard, sharp cementclinker being the cement making apparatus, being interposed between the kiln in which the cement continually fed into the machine. As the pulyerizer constitutes an indispensable link in is burned or clinkered, and the usual tubemill,

the entire chainis thrown out of operation when the pulverizer is stopped for repairs.

Manufacturers and users of mills of this type have for many years endeavored to pro- 1 vide crushing elements having increased wear lor abrasion resisting qualities, using or 6X- perimenting with all metals thought to be stationary ring and three rollers which have rolling contact therewith, I have fabricated the ring and rollers of chllledlron and vari- 'ous alloys of steel, in the endeavor to find a metal which would stand up under the excesslve abrasive actlcn of the clinker. Past experiences have, however, demonstrated that the hardest and toughest materials heretofore believed to be suitable for the crushing ele- -ments of such a mill have not been sufiiciently result that the crushingsurfaces are rapidly fworn away. This attrition ofthe crushing surfaces or elements cannot proceed very far, of course, before such surfaces lose their orig resistant to the-abrasive orcuttin'g' action of the materials being pulverized and that, with any such known materials, the period of useful life of such elements is entirely too short,

much shorter than that of the other moving parts of the mill.

I have now discovered that an alloy of cobalt and other metals of the chromium group, such for instanceas that disclosed in Patent No. 1,057,423 issued to Elwood Haynes, and which alloy is well known throughout the machine tool industry, hasremmost ll'lClQfiDitEt life. The beneficial effects" of this improvement are obvious, the grinding surface retaining its original contour thus insuring absolute uniformity of prodnet and maximum output and mu chtime and expense being saved due to the freedom from shut downs. i

The crushing elements may be formed in various ways, mechanically, and the invention-is not limited to any particular type of mill, it being obvious that crushing surfaces fabricated of the alloy specifiedmay be utilized in mills which vary widely in specific Hill design and construction, that is, the invention will be found useful wherever means is provided for ClLlSlllIlg or grinding materials of such hardness and sharpness as to possess marked abrasive. qualities.

Inthe accompanying drawings one form of mill in which the novel crushing elements are incorporated is illustrated by way of example,-Figure 1 beingaperspective view of the mill and FigureQ-being an axial section through the stationary crushing ring, disclosing two of the crushing rollers.

This mill comprises a base which supports the crushing ring 11, and a revoluble table indicated generally at 12, which carries three crushing rollers 13. The revoluble table 12 and ring 11 are concentric and, as the head israpldly revolved, the rollershave rolling contact with the cyl ndrical inner crushing surface of the ring, as can be seen clearly from Figure 2. In the mill illustrated the table 12 .i-sadapted to be revolved in the direction through asmall mesh screen and falls into a hopper. Any particles too large ,to' pass through the screen are reground,.means being provided to collect such particles and again pass them-between the grinding surfaces.

The action of the rollers in catching. and crushing hard vitreous lumps of cement clinker results in rapid wearof the ring 11 in. elongated patches or areas, In the event that the ring is fabricated of any metal which has heretoforebeen employed or suggested. To-

ward the middleof the ring, as measured vertically, the wearing is particularly noticeable and continued'use of the mill-results ultimately in a hollowing out of'the grinding surface between its upper and lower edges.

This destructionof the cylindrical contour of the crushing ring of course results in replaced. a

My invention consists in fabricating the crushing ringandrollers 1n such a manner duced grinding efficiency and eventually the ring becomes so worn that it must be rethat the actual crushing surfaces are formed of the specified alloy and in Figure% of the drawingsanalloy liningfor the ring 11 is indicated at 15 and alloy 'coatingsor casings for the rollers are indicated at '16. In a mill so constructed, that is, having the active crushing surfaces formed of this-metahthe clinker or other hard-material which may be fed ,of the metal alloy mentioned.

through the same is wholly crushed and without appreciable wear of the surfaces due to the intense abrading action which results.

The alloy may be placed upon the crushing elements in any appropriate way. In the mill illustrated I prefer to weld the alloy to the metal surfaces of the ring and roller but it will be apparent that the lining of the ring may beformed as ahoopor cylinder and suitably secured in position and that likewise the casings 16; ofthe-rollers maybe separately formed when found most convenient. I have also found it satisfactory to use, in connection with the crushing ring lined with the alloy mentioned, crushing rollers which are so not covered, the greatest wear occurring in the ring and not in the rollers, but preferably I surface both crushing elements with a layer Of course, both the ring and rollers may be formed entirely of this alloy but Iprefer'not to do this because of the: great costof the same as compared with other metals which are available as backings for the crushing surfaces. I

I amaware that an alloy of cobalt, chromium and othermember, ormembers, of the chromium group has been used for variousepurposes in the mechanical arts'suclnfor instance, as cutting implements, machine tools, table knives, cutleryand the like, for many yearsand thatit has long been well known as possessing a high degree ofhardness and toughness. So far as I am-aware, however, the property of thisalloy to resist abrasion in grinding or pulverizing clinker or other materials having hard and sharp crystals has never before been discovered. As previously pointed out, the-alloy which I prefer to employ is fully disclosed in Patent No. 1,057,423 issued to ElwoodI-Iaynes, and

comprises an alloy of cobalt with another "to provide a crushing element havingpronounced ability to resist abrasion.

Such mills may, of course, vary in size and shape, in the type and design of the crushing elements, and in the manner in whichth'e crushing operation is performed depending, of course, upon the material to be acted upon.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

1. In a grinding or crushing mill, relatively movable members having crushing surfaces between which the material to be ground or crushed may be introduced, one of said members having a crushing surface comprising an alloy of cobalt and an additiona member of the chromium group.

2. Ina grinding or crushing mill, relatively movable members having crushing surfaces between Which the material to be ground or crushed may be introduced, both of said members having crushing surfaces fabricated of an alloy of cobalt and an additional member of the chromium group.

'3. In a grinding or crushing mill, relatively movable members having crushing sur faces between Which the material to be ground or crushed may be introduced, one of said members comprising a metallic backing member having a Welded-on crushing surface or limng of an alloy of cobalt and an additional member of the chromium group.

at. In a grinding or crushing mill, relatively' movable members having crushing surfaces between Which the material to be ground or crushed may be introduced, one of said members comprising a crushing ring and the other member a crushing roller ar-- ranged to move in a circular path Within the ring, the crushing surface of the ring being formed of an alloy of cobalt and an additional member of the chromium group;

In testimony whereof I hereunto aflix my signature.

' ERNEST H. DIMLER.

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