USRE4739E - Improvement in grinding-mills - Google Patents

Description

NELSON BURR.

rover ne-nt in Grinding Mills.

UNITED STATES PATENT OFFICE.

NELSON BURR, OF EATAVIA, I LLINOIS.

IMPROVEMENT-IN GRINDING-MILLS.

I Specification forming part of Letters Patent No. 94,072, dated August 24, 1869 reissue No. 4,739, dated February 6, 1872.

nying drawing andto the letters of reference marked thereon which form a part of this specification, in which' Figure l'represents the grinding-surface of the ring or disk.. Fig. 2'designates the same form of grinding-surface with Fig. 1, but on a reduced scale. Fig. 3 is a central vertical sec-' tion of the ring or disk.

The nature of my invention consists in the peculiar construction and dressing of cast-iron rings, so as to adapt them for grinding corn or other grain, as set forth.

Afterlongexperience and observation I have discovered, and I claim to have established, a

principle'contrary to that generally received, and to have proved satisfactorily that the mode to increase the capacity of a mill for grinding is not to increase the grinding-surface, butto diminish it, as is exhibited by the rings or disks here shown; As the grinding process is carriedon near the center of motion there is agreat gain of power, and an increased rapid 'ity otmotion obtained; As a neccssaryconsequence ofrapid motion the ceutrifngalforce will be so great as to expel the meal instantly from between the disks, and thus prevent its heating orcloggin The grimiing-surface I place at the extreme outer edge of the disks or rings, and have found that a great advantage'is gained in i'naking, it. very narrow. I

. make this grinding-surface less than one inch say, one-fourth of an inch, more or lessin width, as I find that in ordinary mills where the grinding-surface is broad the grain is car DIVISION A.

ried round and cannot escape fast enough to prevent heating. I also find by experimentthat the grain is ground before the heating takes place. In my invention the meal escapes so soon as it is ground, and before it has time to heat. A mill made after my invention with the narrow grindingsurface will eii'ec'tually grind from three to six times the amount of grain, in a given time, as an ordinary mill with the usual broader grindingsurface and an equivalent power.

A represents a cast-iron disk or ring, an inch,- moreor less, in width on its face, and curved downward from near the outer to the inner circumference. a- I) c d are the ridges or teeth of the grindingsurface, made in the usual manner, except that the actual level grinding-sun face at which the two disks are directly opposed to each other is represented by the narrow border extending only the length inward of the short ridges-l), which I make a quarter of an inch, more orlcss, in length in a disk of five-and-a-half inches diameter, more or less. The outer ridges a c (I proceed from the outer circun'ifcrence to the cntentof the ridges I) in the same manner as said ridges and are prolonged thereafter toward the center in the usual shapes and proportions, to serve as a drift or feeding arrangementto feed the grain to the grinding-surface.

- Having thus described my invention, what I claim, and desire to secure Letters Pat cut, is- I The combination,in a portable grinding-mill, of two'annular detachable grinding-rings, pro vided with narrow grinding-suriaces not ex- .ceedingone-fourth of an inch in width, from which the grain is discharged as soon as it is ground, as specified.

'VVitncsses: NELSOX BURR.

G150. G. LYON,

W D; NIcHoLs.

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