US1430432A

US1430432A - Conical or cylinder grinding mill

Info

Publication number: US1430432A
Application number: US554798A
Authority: US
Inventors: Attalus C Bittner
Original assignee: Individual
Current assignee: Individual
Priority date: 1922-04-18
Filing date: 1922-04-18
Publication date: 1922-09-26
Anticipated expiration: 1939-09-26

Description

A. c. B|TTNER.

CON!GAL 0R CYLINDER GRINDING MILL.

APPLICATION FILED APR. 18. 922.

1,480,432. Patented Sept. 26,1922.

2 SHEETSSHEET lt uc H 501 A C. BITTNER. CONICAL 0R CYLINDER GRINDING MlLL Patented Sept. 26, 1922.

2 5HEETS-SHEET 2.

APPLICATION FILED APR.18, 1922.

Patented Sept. Z6, i922.

W TE e mania V'AT'DALUS c. BITTNER, or CLINTON,'IOWA.

CONICAL OR CYLINDER GRINDING MILL.

Application filed April 18, 1922. Serial No. 554,798.

To all whom it may concern:

Be it known that I, ATTALUs C. BITTNER, a citizen of the United States, residing at Clinton, in the county of Clinton and State of Iowa, have invented new and useful Improvements in Conical or Cylinder Grinding Mills, of which the following is a specification.

separate the fine material and at the same time prevent the grinding charge from be ing discharged out of the mill before thorough grinding ensuesfiand also to obviate the outward passage or discharge of the grinding media such as steel balls or pebbles or any grinding load being used in the mill with the material under normal feed of the material to the mill. The improved device is also provided with means to take care of the overload in the mill.

In conical or cylindrical mills in which material is disposed for grinding purposes through the medium of steel balls or other devices where the mills are lacking in any particular means to control the discharge of the grinding material, the,coarse or unground material and the steel balls or grindin media are always liable to pass-out through the discharge opening with the fine material, and necessitate the return of the coarse material and grinding media into the mill through the intake end of the latter. Moreover, in this class of mills where there is no controlling discharge means at the outlet, a considerable portion of the material that, has been ground sufficiently fine is never discharged, but is turned over and over and remains in the mill and prevents the effective working of the grinding load. The improved discharge screen or grate having a lifting function overcomes these disadvantages and considerable econom results by reason of the fact that the load 1s constantly 'ing cylinder where it would kept where it can grindlng operation. 18 obviated as well carrying the grinding load and coarse material that may be discharged from the mill back to the intake end of the tube. In addition the improved discharge controlling means embodying the features of the present invention is effective in liberating all of the fine materials or fines through the outlet of the cylinder as soon as it reaches the said outlet, and thereby prevents also the return of this finely ground material to the grindact as a cushion and hlnder the grinding of the coarser mat'erial. The improved discharge controlling means or screen or grate and lifter, therefore, automatically and effectually operates to' overcome the numerous disadvantages in prior mills of the type for which proved device has been devised.

The invention consists in the preferred construct-ion and arrangement of the several parts which will be more fully hereinafter described and claimed.

In the drawings:

Fig. 1 is a longitudinal vertical section of a cylindrical mill showing the improved discharge device applied thereto;

Fig. 2 is a detail perspective view of the improved discharge device looking towards the inner side thereof; I

Fig. '3 is a transverse vertical section through the improved discharge device;

-Fig. 4 is a section on the line 4r4:, Fig. 3; and

Fig. 5 is an end elevation of the improved discharge device looking towards the outer end of the same.

i The numeral 5 designates a cylinder havmg a reduced or conically shaped outlet extremity 6 and the opposite end 7 also conically reduced and having a feed chute 8 centrally communicating therewith. The rear or receiving extremlty 7 is provided with, the usual driving gear 9 for rotating the; cylinder by suitable mechanism, and to facilitate rotation, the cylinder is supported on pedestals 10 on which are secured bearing blocks 11 and 12. Theopposite extremities or ends of the cylinder are also provided with

trunnions

13 and 14 for a purpose which will be readily understood, these parts being common in the art relating to this type of grinding mills. The trunnion 13 has a continuous slightly flared discharge spout 15 the im- I around the open end 16 constituting the discharge outlet of the cylinder. Within the cylinder grinding devices such as balls, pebbles and other grinding media are placed and serve by impact to pulverize or grind the material fed into the cylinder through the intake, or inlet end or extremity 7 by the chute 8. v

The present invention relates particularly to discharge means, and though shown applied to the rotatable cylinder or drum 5 of common form, it may equally well be used in connection with any other analogous grinding container, the shape of the cylinder or container not in the least controlling the function and operation of the improved discharge means or organization which is shown in detail by Figs. 2 to 5, inclusive. The improved discharge means or organization.

comprises a truncated conical casing 17 formed from a suitable thickness of sheet metal and having an outside dimension approximately the same as the interior dimension of the outlet or discharge end of the reduced conical extremity 6 of the cylinder 5. Extending centrally through othe casing or body 17 of the improved discharge means or organization is a tube 18 fully open at both ends and having the double function of servingas a hollow core for the discharge means and especially as an overload outlet.

Radiating from the tube 18 are segmental screens or grates 19 continuing fully outwardly to the inner surface of the surrounding casing or shell 17 and peripherally fixed to the "latter. These segmental screens or grates also continue from the inner end to the outer end of the casing or shell 17, and from the radial edges 20 of the said screens or grates 19 imperforate concavo-convex sheet metal sections 21 extend and are also continued outwardly from and peripherally secured to the inner surface of the surrounding casing or shell 17. The sections 21 are of segmental form and each section has its outer reduced edge 22 terminating coincidently with and secured to the outer edge of the screen or grate next in advance of that from which the inner edge 23 of each screen or grate starts. This alternate arrangement ofthe screens or grates 19 and the sheet metal concavo-convex sections 21 is regularly carried out around the interior of the casing or shell 17 and the tube 18. The convex sides of the imperforate sheet metal sections 21 are disposed innermost, or at the enlarged receiving end of the improved discharge means. By this arrangement of the sections 21 the outer convex surface or sides thereof are adjacent to the outer sides of the screens or grates 19, so that when the ground material is discharged through the screens or grates, it is taken up and forced outwardly through the outer or outlet end ofthe discharge means.

The improved discharge close against the inner enlarged receiving end of the improved discharge means or organization. This ring 24 will not in the least interfere with the effective operation of the discharge means, as it will preferably be of about the same thickness as the metal of the casing or shell 17.

The operation of the improved grinding or reducing mill hereinbefore described is the same as in Well known devices of this character, and the material to be ground or reduced is admitted into the cylinder 5 through the chute 8 and the cylinder then rotated to cause the balls, pebbles or other grinding media to comrninute or pulverize the material. In well known grinding mills of this type the grinding material is discharged through a hollow trunnion at the discharge end similar to the trunnion 13 with the spout 15, and the disadvantages incident to this unrestricted or free outlet has been hereinbefore specified and 7 consists mainly in the discharge of coarse material and the grinding media with the fine material and the necessity of replacement of the coarse material and grinding media through the intake end of the cylinder by Way of the chute 8. In the present improved construction the discharge means or organization and comprising the screens or grates 19 and the imperforate concavo-convex segmental sections 21 arranged as hereinbefore specified, the finely ground material or fines is taken up and delivered or discharged through the screens or grates 19 and then pushed or propelled outwardly by the concave front or outer sides of the sections 21 through the outlet end of the improved discharge means around the center tube 18. At the same time under normal load of the mill the coarse material that might otherwise escape together with the grinding media that may shift or settle towards thedischarge end of the cylinder will 'be pushed backwardly by the inner convex sides of the segmental sections 17, and a material amount of agitation or throwing up of the coarser material and grinding media will be effected adjacent to the inner end of the discharge means,"and as a consequence, there willbe less tendency-of the finely ground material to settle towards the bottom or cover and shield the coarse or unground material, and therefore the grinding media will be free to operate on the coarse material and reduce the same to the predetermined degree of fineness. However, it will be understood that the fine material will be taken up and rapidly discharged through 'the screens or grates 19, and in those grinding mills where the cylinders are canted 38o chine and the adjacent convex inner side-of each imperforate section .21, a pocket will be formed at the inner portion of the discharge means, and through the medium of this pocket formation, which continues around the discharge means, a regular liberation and outlet of the finely ground material or fines will ensue.

In practical operation of mills of this character the material to be ground isu'sually fed automatically thereinto, the speed of the operation or process of grinding varying with the toughness and hardness of the material being ground, and consequently, the machine is overloaded at times. If no provision is made to take care of this overload, the entire machine soon becomes choked, for the reason that when the machine is overloaded the grinding process is retarded. To take care of this overloading of the mill or machine, the tube 18 is used, the latter not only serving as a supporting means as hereinbefore disclosed, but also as an overflow device. When the machine is overloaded, not only the material to be ground but the grinding media may pass through this tube, to relieve the over-charge of the mill or maand subsequently the material or grin ing media thus discharged through the tube may be taken back and reinserted in the c linder or body of the mill through the fee ing means therefor. Under normal conditions, however, none of the material to be ground or grinding media will be delivered through the improved discharge means, the fine material, or the material that has been successfully ground, being the only part of the contents of the cylinder that isdelivered through *the improved discharge means.

It wi 1 also be seen that a straight screen wall and a convex imperforate bufling wall adjacent to the screen wall will continue in sequence around the interior of the casing or shell 17, and as the im roved discharge means regularly rotates with the cylinder, it. will have a lifting action with respect to the fine material and a repellant action with respect to the coarse material and grinding media, which is of material advantage in a discharge means for a mill of this type. Moreover, the disposition of the screen walls and imperforate convex bush ing walls around the interior of the casing or shell will have the effect of drawing the fine material into the discharge device to the best advantage for discharge purposes and .facilitate the outlet of the finely ground material.

It will be understood that the proportions and dimensions of the improved discharge device as. a whole may be varied at will in accordance with the dimensions of the adapted to be applied and also in accord ance with the character of the material to be round.

hat is claimed as new is: a 1. A grinding mill of the character specified,-having a discharge device comprising radial screen walls arranged in alternation with concavo-convex closing sections.

2. In a grinding mill of the class specified, a rotating container for receiving material to be ground and grinding media, and a discharge device secured to one end of the cylinder and rotating with the latter, the discharge device being provided with alternately arranged outletscreen. walls and closed walls.

3. In a grinding-mill of the class specified, a rotatable grinding cylinder, and a discharge device secured to one end of and rotating with said cylinder and provided with radially arranged outlet screen walls and alternate concavo-convex closed walls extending from the inner end edge of one screen wall to the"outer end edge of. the next screen wall.

4. In a grinding mill of the class specified, a rotatable grinding container, and

fied, a rotatable grinding container, a discharge device secured to and rotatable with the container and having radial screen walls arranged in alternation with concave-convex closing sections, and a central outlet means to take care of the overload of the mill.

In testimon whereof I. have hereunto set my hand 1n presence of two subscribing witnesses.

. ATTALUS C. BITTNER. Witnessesz' FLoRnNoaG. SHIPE,

ELsm I. OULP.