US813903A - Grinding-mill. - Google Patents

Description

PATBNTED PEB- 27, 1906.

P. T. LINDHARD. GRINDING MILL,

APPLICATION FILED JULY 1, 1904.

2 SHEETS-SHEET 1.

Ami

IIIIII/I/IIIIIIIIIIIIII PATENTED FEB. 27, 1906.

P. T. LINDHARD.

GRINDING MILL.

APPLICATION FILED JULY1,1904.

' z SHEETS-SHEET 2.

'IIIIl/I It'll ground or pulverized chine. tor separating sectional view taken] on the plane indicated by the line 2 2 in Fig. l and looking toward ri'rvrrnn g'lAglfES PATENT ornron.

reel 1, LINDHARD, or NEW YORK, n. r.

Specification of Letters Patent.

Patented Feb. 2?, recs.

Application filed July l, 1904. Serial No. 214,850.

To will wi'ww t it may conceive:

Be it known that l, PovL 'l. LrnnnAnn, a subject of the King of Denmark, end it resident of the borough of Manhetten, city of New York, State of New York, have invent- 7 ed certain new and useful Improvements in Grinding-Mills, of which the followin is a specification, reference being bad to t e occom psnying drawings, forming a pert hereof.

This invention relates to grinding-mills, and particularly to ball grindingmills in which'the materiel to be ground is fed into a drum or other rotating member, where it is by the crushing action of the bells provided therein. In the reduction of 11' course material by such mills it is customary to. introduce the meteriel first into e mill having relatively large balls, where it is crushed up and round to a certain fineness, end then to feed the ground materiel into a, second mill, in which the bells are relatively smaller, where it is pulverized. Such a. method of reduction, as is clear, re-

uires the employment of two machines. such attempts esheve been made heretofore to carry out this method of reduction by means of a single machine have, so far as is known, been unsatisfactory.

The object of this invention is to provide a mill compact in construction in which the crushing, grinding, screening, or sifting end the lulverizingof the material can be accomplis red. at the some time and in a single me.- For this purpose means are provided the finely-ground material from the coarser particles or tailings after thsfirst grinding and to return the tailings to the grindin or crushing drum for further re duction and to'discherge the finely-ground material to s second drum for pulverizing.

In the accompanying drawings, in which one embodiment of theinvention isillustreted for purposes of explanation, Figure 1 is e view in vertical central section. Fig. 2 is 8.

Figs. 3 and 4 are respectively sectiozm views taken upon the planes indicated by tl ines 3 end i in Fig. 1 end looking l towcrd the l We 5 is a detail cross-sew 1 tion taken on line 5 5 of Fig. l. in accordance with the invention the mill l has three com mrtments-the drum o which I receives the materiel 'to be ground, the drum l), in which the finely-ground material is pul- I separating-drum or sepethe right.

verized, and. the

into! 0, which receives the i'neteriel from the to the drum 1:, and returns the teilings to the drum a.

together". in any suitab e manner, the separator being intermediate the drums (1 and end the axes of the three drums being pref erebly in the same line. Trunnions (i only be provided at either end of the apparatus to rest in journal-bearings e, and any suitable means (not shown) muy be provided to rotote the drums in said bearings.

The construction of the drums a and b is immaterial to the present invention. The first drum 0,, receiving the material to be ground from a hopper f, which may be provided with a feeding device, such as e wormshaft 9, may have a relatively large diameter as compared-with the drum 1), while the latter may be somewhat longer than drum a. The interior surfaces of the drums may be plain, as shown in Fig. 4, or corrugated, as shown in Fig. 2, or stepped, as shown in Letters Patent of the United States 0. 69%,974, dated March 11, 1902, or otherwise formed. Both drums are provided with bolls suitable for performing the work required, the balls in drum a being preferably larger and heavier for grinding and crushing "hen the bulls in drum 5, which do the pulverizing.

The separating-drum or separator c is pro vided with screens 11., of which any number may be employed. These screens extend from neer' the center of the drum to the circumference or periphery thereof and are profersbly curved, as shown in the drawings, so that the material which enters from the drum These three parts mey be secured a through openings 71 may strike the concave side of the same and slide over the screens as the separator rotates. it will be clear, however, tlmt, if desired, the screws may be straight and substantially redial. that the screens may be easily removable, they are preferably secured to the separator by forming grooves is in each of the. ends or heads Z of the separeting drum c, in which grooves the screens are held. The openings l are made of such a. size as to permit nmtoriel of a certain fineness only to enter the scperw tor, end these openin s are arranged in iron t of the screens--tlmt is, so that the material. entering through the same will drop upon the concave surfaces of the screens. The openings 'L are furthermore located, preferably, near the circumference separator. Behind each screen is a purtiti on In order lOO TIC

m, which preferably conforms to the curvature of the screen and which serves to receive the sifted matter from the screen and to keep such sifted matter from becoming mixed with the fresh material entering the separator.

from the drum a. These partitions also prefcrably serve to unitethe two ends or heads l of the separator, while the circumference of the separator is closed by a" removable circular band a, the ends of which are secured together by bolts 0. When the bolts are removed, the band is detached from the separator, and the screens may be withdrawn and the interior of the separator easily gotten at and cleaned.

Near the center of the separator means of communication are provided between the drum a and the forward side of e' ch screen" that is, the side upon which the material is received from drum a and between the drum 1) and the other side of'each screen-that is,

the side where the finely-ground or sifted ma terial is delivered as it passes the.screen--. whereby as the mill rotates the tailings are. returned to drum a and the finely-grounder sifted material is discharged in drum b. For this purpose inclined plates g are provided, and these plates are arranged between-the screens h and the partitions m, the plates in front of the screens being inclined so as to discharge into the drum a, while the plates behind the screens are inclined so as to discharge into the drum '1). In the construction shown in the drawings there are four screens tions were continued into the center the lower or inner end. of each'lnchncd plate would form substantially an. angle of tortvfive degrees and. that the discliarge would take place through a 'l unni el-like passage formed by a screen, a plate, :tnd a partition and having a relatively narrow dischargc-' .openingwhcreby it would be possible For the tailings or lines, as the case might be, to choke up such passage and opening. While such a construction is within the purview of this inventiol'i, the screens are preferably not continued to the center of theseparator; but the separator is provided at its center with a cylindrical structure whose periphery is indicatcd atr and through .which periphery the plates (1 extend. That portion of the periphery in front of each plate, however, is removed, so as to permit the free passage of the .material down the slide. lnthis way the slides discharging into drum 1) are broadened out after they pass the periphery 7' oi the centhe discharge quadrants unobstructed. e ther drum is to contain a large number of tral cylindrical structure, and the lower or inner ends of these plates form angles of ninety degrees with'each other and are bounded on each side by partitions m, Figs. 2 and 3. One end of the central cylindrical structure has thus tour discharge-quadrants t, aswill be seen particularly from Figs. 2 and The other end of the central cylindrical structure is similarly provided with four discharge-quadrants 8, formed by .partitions p, extending from the inner ends of the screens to the center of the separator and between which the lower ends of the plates discharging into drum (1 are received, the lower or inner ends of these plates being thus formed similar with the corresponding ends of the plates discharging into drum 1). 'Moreover, it will be clear from the drawings that within the central cylindrical structure the partitions m are cut away. on one side from in front of the plates and that the partitions p are similarly cut away upon the other side, so as to leave It balls, as the drum b is-shown in the present case, a circular plate a may besecured in front of the discharge-openings from the separator, leavim a narrow space between said plate and the read through which the finelyground material may passinto the chamber among the balls, but preventing the balls from entering the separator. It will be obvious, of course, that a similar plate may be placed in front oi" the openings at the other end of the se arator, although the same is not shown in thedrawings. I p

i In the operation of the mill the material to be ground is )laced in the hopper f, from which it is Fed into the drum (1, where it is crushed and ground and from which it onters a separator through the openings i in front of the screens h, (the mill being rotated in the direction of the arrow, Fig. 3 Such material as enters the separator slides over the screens as the mill rotates, and the sifted material drops upon the partitions m beneath the screens and is discharged through the openings 8 into th drum b. The tailings which do not pass the screens are returned to the drum (1 through the ownings t. The linely-grouml material enteril pulverized therein and discharged into a dust; casing 11, comi'nunicating with an elevator, conveyer, or some other suitable device (not shown) for removing the material from the mill. The tailings returned to the drum c are commingled with the fresh material entering from the hop er and are aga'in'subjected to the action 0 the balls in said drum.

It will be understood that the mill is capable of many modifications and that the invention is not limited to the precis form shown and described.

I claim as my 1nV611t1011-- 1. in a grimling-mill, the combination of'a g the drum 1) is material from said drum and provided with the other of the drums.

' grinding-drum to receive the material to be ing inlet-openings meeting into the comerases mind, a separator havin a com artment ormed therein to receive t e part y-ground means Within the compartment for separating finely-ground material from the tailin s, and a second grindin -drum to receive t e finelyound materia from the separator and pu verize the same.

2. In a grinding-mill, the combination of a grinding-drum, means to deliver thereto material to be ground, a separator having acornpartment formed therein, means to deliver the partly-ground material to the separator, and a second grinding-drum, said separator havin means within the compartment adapted to deliver the finely-ground material to the second-named drum andalso having means within the com artment ada ted to return the tailings to t e first-namet drum.

3. In a grinding-mill, the combination of two grinding-drums, and an intermediate separator having a compartment formed therein, said separator having screens and partitions within its compartment and hav partment, the separator being also rovided with discharge-openingson one Sl( e of the screens communicating with one of the drums, and having discharge-openings on the-other side of the screens communicating with the other drum. 7

4. In a. grinding-mill, the combination of two grinding-drums, and an intermediate separating-drum, said separating-drum having therein a plurality of screens and having artitions behind each of said screens to catch the sifted matter, the drum also having inlet-openings near its periphery and discharge-openings near its center, both said inlet and discharge openings being on one side ol the screens ant conln'nmicating with one of the drums, the separating-drum also having discharge-openings upon the other side of the screens and communicating with is in a grinding-mill, the combination of twogrinding-drumsand an intcrmediatcseparating-drinn, said separating-drum having a plurality of curved screens, and havin inletopcnings near its periphery and discnargcopenings near its cenlcr, both said inlet and 1 discharge openings bcing upon the concave sides of said screens and communicating with l one of the drums, lho scparating-drum also l having a partition upon the other side ol'cach ol' the screens upon which the sil'tcd matter is received and having a rlischargo-opcning between each screen and tho corrcspmlding partition communicating with the other drum.

(5. in :1 ball grimling-machine, the combination ol a grinding-drun-r having relatively large and heavy balls, :1 second grindingdrum having rclati\"cly small and light balls, I

ing drum also having discharge openings I upon the other side of" the screens commune,

eating with the drum having the smaller balls. v

7. In a grinding-mill, the combination of two grinding-drums, and an intermediate separating-drum, said separating-drum having within it a plurality of screens and partitions extending from near its center to its periphery and having inlet openings on one side of the screens toward or near the periphery communicating with one of the drums, and also having two sets of dischargeopenings toward or near the center, one set being on the same side of the screens and communicating with the same drum as the inlet-openings and the other set being on the other side of the screens and communicating with the other drum.

8. In a grinding-mill, the combination of two griruling-drums, and an intermediate separating--drum, said scparatinglrum having therein a plurality of screens and partitions extending 'lrom'near its center to its periphery and having inlet-(mcnings on one side of the screens toward or near the periphcry cormuunicating with one oi the drums, and two setsioi inclined plates within the separating-drum, the plates in one set extending from the same side of the screens on which the inlet-openings rem one drum to the separating-drum are located, and the plates in the other set extending from the other side of the screens to the other drunr i). in a grinding-mill, the col'nhination of two grimling-drums, and an intermediate scparating-drum, said separating-drum having therein a plurality ol' screens extending from near its center to its )cri ihcr a )lurality of partitions extending lrom the ends oi the screens to the center of the separatingl drnm, a plurality m' partitions extending from the center of the separating-drum to its periphery, the scparating-drum having inletopcnings on the l'orward side of the screens comnrunicating with one drum, and two sets of inclined plates, the plates in one set extending lrom the spaces between the forward sides oi the screens and the secondnamod partitions to the same drum with a which the inlet-openings communicate, and

the other set extending from the spaces hetween the rear sides of the screens and the and the other set of plates crossing the secmovable band around I end-named partitions which are cut 0 ll above the plates, and. a central cylindrical structure through which the plates extend.

10. In at SGPiLIZltiUg-(llllfll for ball grinding-mills and the like, the combination of the ends or heads of the drum, having grooves extending from near the center toward the periphery, screens in the grooves, and a re (l'ruin. I

This specification signed and witnessed this 21st day of June, A. D. 1904.

POVL T, LINDHARD.

In presence 0f-- ANTHONY N. JESBERA. LUCIUS E. VARNEY.

the periphery of the 0

Images