US1589741A - Pulverizing mill - Google Patents

Description

June 22 1926.

1,589,741 L. c. BON'NOT ET AL PULVERI ZING MILL Filed Nov. 4, 1925 4 Sheets-$heet 2 v I I Jwumtou L.CB0IZ7Z0LZ W 53 f1. flarker @M PULVERIZING M 4 hoet 5 File 1925 June 22 1926.

L. C. BONNOT ET AL PULVERI ZING. MILL Filed Nov. 4, 1925 4 Sheets-Sheet 4 gmmw Z. 6130222205 2 Mflffiarz r Patented June 22, .1926.

UNITED STATES LOUIS C. BORN-'1, OF LOUISVILLE, AND WILLIAM H. BARKER,

a 1,ss9,741 PATENT OFFICE.

or CANTON, 0310,.-

srenons TO THE BONNOT commemorcannon, oman coaronsrron or 01110;

Application filed November The invention relates to a rotary drum grinding or pulverizing mill partly filled with balls or other grinding media for the vide a machine of this character having means for preventing the grinding media from being thrown or drawn into the fan of the se arator and damaging the same, and provlded with an exhaust cone in the discharge end of the mill, leading to the separator, and. having spiral fins and a receding, concave, peripheral flange, for plowing or deflecting and repellingthe balls and coarse material away from the cone and continually forming a furrow in the ball mass adjacent to the peripheral flange for receiving among the balls any coarse material which is by-passedfrom the exhaust separater and returned through the nozzle in the cone to the mill. 0 Also, to provide means for returning to the drum any coarse; material which may; be thrown 'or drawn into ,the cone; to provide for a decreased suction at the exhaust side of the drum and an increased suction in the exhaust end of the cone by means of the diflz'erence in area of the opposite ends of the cone, in order to carry. only the finely pulverized portions of material into the inlet end of the cone; the increased velocity, at the outlet end of the cone serving to quickly exhaust the fine material through the exhaust separator and providing suflicient velocity to preventthe fine material from settling in the passages and obstructing the same: the decreased,ve-.

locity at the exhaust side of the drum, however, being sufiicient to carry thefinely pu1- verized material out of the drum and .prevent the same from settling in the mill and cushioning the balls.

And finally, to provide a bypass and centrifugal separator exhauster, to create a counterdraft through the nozzle into the TCOIIB for returning to the drum oversized material segregated by the exhaust separator as well as to clear the, cpne of any'coarse material. which may at the outlet side of the 4, recs. Serial no. 66,855.

deposited therein by the grinding action; thus making a complete separation of the finely pulverized material and eliminating the necessity of using an'independent cycle separator'or other separating apparatus.

The lmproved mill is well adapted for pulveriz'ing small lump orslack coal foruse in furnaces or powdered fuel feeding systems, but 1t should be understood that it is equally well adapted for ulverizing other coarse or granular materia s. y

The present improvement also contemplates the elimination of the usual axial tube or center ipe extending into and sometimes throught e drum, in air swept mills, the raw material being fed referably through an inlet cone and througi an axialopening into one end of the drum, a perforate bafile plate in the center of this opening breaking the suction through the axial center of the drum. The drum is preferably supported upon flanged rollers journaled upon a shaft, and is provided with a ring gear meshing with a driving pinion carried in an adjustable bearing. I m An embodiment of the improved pulveriz- 1ng mill is illustrated in the accompanying drawings, forming part thereof, in which- Figure 1 is an axial section through the improved mill;

Fig. 2, a section on line 22,-.Figure 1;

Fig. 3, a section on line 3-3 Figure 1;

Fig. 4, a vertical section through the centrifugal exhaust separator, and

Fig. 5, a fragmentary section on the line 55, Figure. 1, showing the action of the spiral finsand counter-current from the exhaust separator. 7

Similar numerals of reference indicate correspondingtparts. i

The grindin drum 10 is mounted upon the flanged rol ers 11 which are journaled G upon the shaft 12, and is arranged to be .driven through the ring gear, 13 carried upon the drum, and the driving pinion 14, mesh- 100 ing therewith, and-j'ournaled upon brackets/ 15 arranged to'be'adjustably mounted upon the supporting base 16 as by the bolts "17 ahd adjustin screw 18.

The in at end of the drum may be provided 106 with the axial feed cone-19, and a perforate disk 20 is mounted in the o enin thereof and connected to the en wall of'the cone as" byx-ra'dial wings 201 .and bolts 21.

.The periphery of this disk is spiaedzfromthe no.

ofthebase periphery of the feed opening of the drum, as shown at 22, permitting the greater part of the material to be fed around and beneath the disk into the drum, while the perforate disk permits a portion of the air to be drawn axially through the drum, breaking the direct axial draft from the feed inlet tothe exhaust cone and preventing any but the very finest particles of the material from being carried directly into the outlet or discharge cone of the drum.

r The discharge or exhaust cone 23 is connected to the discharge end of the drum as by the peripheral flange 24 and bolts 25. This discharge-cone may be provided with a lining formed of segmental sections 26 provided with the spiral fins 27, the inner ends of which are spaced from each other near the small end of the cone and the outer ends of the fins preferably extend over the angles of the peripheral rim flange 28 and terminate in the receding annular groove '29 formed in" said flange. v

The discharge cone exhausts into the dis charge neck 30, which is connected to the inlet opening of the centrifugal fan chamber 31 of the exhaust separator and is preferably provided with an angularly dis osed screen 32, of substantially coarse mes to deflect any balls'which may be thrown into the same.

An exhaust impeller 31 is located within the fan casing 31 and is arranged to be ro-' tated as by the motor 33. An outlet pipe 34 communicates with the fan casing for carrying away the finely pulverized material which is exhaustedfrom the drum.

A by-pass 35 communicates with the outlet side of the fan casing and extends be= neath the pan 36 in the discharge neck 30, saidvpan having a deflecting flange 37 substantially parallel with the bottom wall of the discharge cone and forming a nozzle arranged to project a blast of air inward along the bottom wall of the cone.

This centrifugal-fan by-pass construction has three functions; first, it acts asa centrifugal separator, segregating the over size material which is drawn into the exhaust separator and providing a passage for the. return of the same to the mill for regrindmg; second, it sets up a counter-current of air from the end of the nozzle, through the exhaust cone, that tends to prevent the coarse material from being drawn into the cone;

and third, it continually cleans the walls of the cone from any coarse material which may be deposited thereon;

As a consequence the capacity of the mill s greatly increased because suificient suction 1s maintained to withdraw all of the fine material as soonas the same is pulverized to the proper mesh, while the greater portion of the coarser material is repelled from entermg the exhaust cone, and any small pore of the discharge centage of the coarse material which is carried into the exhaust cone by the gradually essity of a cyclone separator or other independent separating apparatus.

With this construction, the material. to be pulverized is passed from the inlet cone, around the periphery of the perforate plate 20, and only the very finest material is carried through the "perforations and axially through the drum to the exhaust cone.

The material is thrown varound in the drum with the balls 38 by centrifugal action, pulverizing 'the material, and only the very finest particles thereof are, exhausted through the fan, as the area of the large end cone is several times greater than the area of the discharge end thereof, providing a comparatively low velocity of suction at the large end of the cone, which will pick up only the very finest terial, and a greatly accelerated velocity of suction at the discharge end of the cone, quickly clearing the same of the fine particles of material.

particles of macharge into connecting bins with such uniformity as not to require any grading or classifying. I

The balls and coarse material are repelled from entering the large mouth of the discharge cone and are prevented from riding up upon the walls thereof by means of the annular groove 29 and the spiral fins 27, and

coarse material is further repelled and prevented from being carried up along the walls of the cone by means of the counter air current above described, while any balls which may be thrown into the exhaust neck will strike the screen 32 and be returned to the drum by the above described means.

The means for preventing grinding balls from entering the fan and the forate disk in the feed opening, which are illustrated and described but i not claimed herein, are made the subject matter of parent application, Serial No. 47,039, filed July 30, 1925, by these applicants.

-We claim: i =1 1. A material pulverizing millincluding a rotary drum wit grinding media therein, a feed opening in one end of the drum and an axial discharge cone flared inward formin an outlet opening extending from the other end of the drum, the mouth formed by the larger end of the cone being substantially unobstructed, means impelling a current of air through the drum from the inlet to the outlet ereof, and peripheral means repellingthe entrance of grinding m dia and coarse use of a perl material into the mouth of the discharge 2. A material pulverizing mill including a ml rotary drum with grinding media therein, a [6 feed opening in one end of the drum and an axial discharge cone flared inward forming an outlet opening extending from the other end of the drum, means impelling a current of air through the drum from the inlet to 10 the outlet thereof, and means repelling the entrance of grinding media and coarse madrum, means impe ling a current of air through the drum from the inlet to the outlet thereof, and spiral fin's on the interior of the discharge cone extending over the rim flange thereof.

4.- A- material pulverizing mill including a rotary drum with grinding media therein, a feed opening in one end of the drum and an axial discharge cone flared inward forming an outlet opening extending from the other end of the drum, means impelling a current of air through the drum from the inlet to a the outlet thereof, means repelling the entrance of grinding "mediaand coarse material into the mouth of the discharge cone, said means including an outwardly flared rim 40 flange connectin the large end of the discharge cone wi the peripheralportion of v the drum, and spiral finson the'interior of thedischarge cone extending over the rim thereof. p

5. A material pulverizing. mill including arotary drum with grinding mediatherein,

a feed opening in one end of the drum and an axial discharge cone flared inward form ing an outlet opening extending from the other end of the drum, means'impelling a current ofair through the drum from the inlet to the outlet thereof, means repelling the entrance of grinding media and coarse material into the mouth of the discharge cone, and a nozzle in the discharge end of the cone projecting a current of air inwardly along the bottom wall thereof.

6. A pulverizing mill including a rotarydrum with grinding vmedia therein, a discharge cone flared inward at the discharge on end of the drum and'having a peripheral, angularly flared rim flange provided with an annular groove for deflecting the grinding media away from the entrance to the. cone.

7. A pulverizing mill including a rotary drum with grinding media therein, a dis charge cone flaredinward at the discharge end of the drum and having a peripheral, angularly flared rim flange provided with an annular groove, and spiral fins on the in terior of the cone extending into the annular groove for deflecting the grinding media away from the entrance to the cone.

8. A pulverizing mill including a rotary drum with grindlng mediatherein, a discharge cone'fla-red inward at the discharge end of the drum, anexhauster separator communicating with'the discharge cone, a

return air discharge nozzle in the discharge end, of. the cone and a vby-pass from the outlet sideof the exhauster separator to the nozzle.

'9. A pulveiizing mill including a rotary drum with grindlng media therein, a di'scharge cone flared inward at the discharge end of the drum, an exhauster separator commumcatmg with the discharge cone, a return air discharge nozzle in the discharge-end of the cone, 9. by-pass from the outlet side of a the exhauster separator to said nozzle and a deflecting flange upon the nozzle spaced from the walls of the cone. In testimonythat we claim the above, we have hereunto subscribed our names.

, Louis 0'. BONNOT. WILLIAM M. BARKER.

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