US1440002A - Grinding mill - Google Patents

Description

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`F. n. BRADLEY. GRINDING Ml L 2 SHEETS-SHEET 2 FILED FEB IIII Ill HHH i? Patented om. 2e, reza.

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FRANCIS DEAN BRADLEY, OF GOLDFIELD, NEVADA..

GRINDING MILL.

Application filed February 18, 1920. Serial No. 359,546.

ATo all whom t may concern Be it known that I, F nANors D. BRADLEY, a citizen of the United States, residing at Groldfield, in the county of 'Esmeralda""and' State of Nevada, have invented a new and useful 'Improvement in Grinding Mills, of which the following is a specification.

This invention relates to cylindrical crushing and grinding mills used in comminuting ores, minerals or the like, and more especially/ to a combination rod and pebble mill. It is a well established fact in the present methods of crushing ores with steel balls, that the mill must be of larger diameter to effect the necessary impact crushing than when employing steel rods, also due to more grinding surface in contact on the rods and less voids between their surfaces; rod mills of a smaller diameter are more efficient and consume less horse-power to operate; although asis commonly known, material is not pulverized to the degree of ineness in rod mills as attained in pebble mills when used for extremely fine comminution or sliming. Rod mills for primary grinding are practically of the same diameter as the finer grinding tube mills. The `present invention combines the merits of the rod mill and the tube mill by accomplishing in a single apparatus two stage reduction, employing the more efficient method of impact crushing with rods followed by l attrition grinding inv an additional compartment using pebbles orfballs.

@ne of the objects of the present invention is to 'improve the resent type of rod mill by dividingthe grinding cylinder into two or more compartments wherein the primary coarse crushing is accomplished in the first compartment with steel rods and finer grinding is produced in the second compartment by the use of pebbles or balls.

AnotherI object of the invention is to provide means for reducing the viscosity .of the ground pulp 'as it passes through the mill.

Another object of the invention is to provide meansfor facilitating the inspection and removal of the rodsin the first crushing compartment. l

Another object of the invention is to provide a novel head or partition member for `separating the compartments and in conjunction therewith means for removing parts of the same to facilitate removal of the crushing rods;

v Further objects will hereinafter appear.

The invention consists of the parts and the construction, combination. and arrangement of parts, as hereinafter more fully described and claimed, having reference to the accompanying drawings, in which- F ig. 1 Vis a central longitudinal vertical I vsection through one form of the apparatus.

Fig. '2 is a cross Section on line 2-2, Fig.' l, partly brokenV away. F ig. 3 is an enlarged section of the partition member taken at right angles to-Fig. 2.

Fig. 4 is an end view of the interior of the apparatus showing the grinding rods suspended on cross bars and part of the parl tition member removed.

Fig. 5 is a side elevation of a modified form of the apparatus partially broken away and partially in section.-

' Fig. 6 is an enlarged detail view of the valve attachment for supplying solutions to the second compartment.

Referring to the drawings in detail, A indicates an elongated cylindrical membery constructed along lines common to tube mills and the like. This tubeor cylinder is divided by a` transverse partition generally indicated by the numeral 2 and two separate compartments indicated at 3 andIl 4 are in this manner formed. The tube or cylinder is provided with heads 5 and 6y ofv any approved detail construction and driven in practice in any suitable manner; The heads have trunnions formed with axial bores constituting respectively the inlet and outlet for the material, the heads in practice -turning in suitable supports not shown. The respective trunnions are indicated at 7 and 8, the trunion 7 being provided with a scoopfeed 9 by which the material to be ground is delivered to the first compartment. The trunnion 8 is alsoihollow and serves asa discharge from the pebble containing chamber `ring 10 secured interior of the` cylindrical.`

shell A. This ring is provided with a pair of interspaced annular shoulders 11 for the reception of sectional interspaced head1/ members 12 and 13. Each head member consists of four sections such as shown in Fig. 2, each section being so constructed that it may be removed independent ofv any other section. This is accomplished in the following manner:

Formed on each section is a flange 14, the inner face of which is angularly disposed or inclined as at 15. Engageable with said flange is a lug 16 and adapted to draw said lug against the flange 14 andthe ring 10 is a bolt 17. Each lug engages two aligned i sections and when removed does not disturb the remaining sections. There is one bolt 17 and lug 16 for each pair of aligned sections and these serve the function lof securing the peripheral edges of the respective sections. Means have also been provided for centrally securing the sections. This means, as shown at 18 and 19, consists of a pair of circular plates having shoulders formed thereon engageablewith wings or ribs 20 formed on the inner faces of the head sections. These ribs form two functions: first, that of receiving and supporting the central securing discs 18 and 19; and secondly, that of blades or vanes whereby material iscarried from the outer periphery of the heads to the center portion of the same as will hereinafter be described. The `central discs 18 and 19 are secured by means of a bolt and nut 20 and as they engage the inner ends of the ribs or vanes 20 on the respective head sections, it can readily be seen that these are rigidly secured when in position.

By referring to Fig. 2 it will be seen that the head sections 12 are provided with 10ngitudinally extending radially disposed slots or perforations 21. These are arranged at the periphery or near the outer edges of the several sections vand serve the function rof discharge openings for the material ground by the rods in the first compartment. Material entering the slots 21 collects in a central chamber 22, forwmed between the respective head sectionsl and it is discharged therefrom and into the pebble chamber through radially arranged slots 23, formed in the central securing disc 19, thematerial being elevated to said slots by means of the ribs or vanes 20. vMaterial passing through the mill will therefore first enter through the trunnion 7 and when ground to a predetermined size enter the central chamber 22 through the radial perforations 21. 1t is then elevated to the center portion of said chamber by the vanes 20 and then discharged into a pebble mill chamber through the centrally disposed perforations 23. The material is then subjected to its final grinding action and is then discharged through the trunnion member 8,

1n any grinding apparatus as disintegration of the material proceeds, the superficial area of the material exposed to the surrounding crushing elements increases. This is a desirable feature in the primary crushing compartment as an aid to grinding, but as the pulp vcontinues, on its course the increased friction between particles createsa sluggishness or state of viscosity Which retards progress toward the discharge end of the mill. This objection is overcome in the present instance as means is provided for introducing a solution to increase the moisturecontent and the mobility of the semifluid mass through the final grinding compartment.

1n Fig. 6 the detail construction of a valve for admitting the liquid is shown. The valve consists of a collar l25 which is secured to and rotates in unison with the trunnion delivers 'the liquid to the annular groove 26 and it is discharged therefrom by means of pipes 30 which are secured to the collar 25 and rotate in unison therewith. These pipes are extended to the pebble compartment as Ashown in Fig. 1, or as illustrated in Fig. 5,

and practically any quantity of liquid may therefore be delivered by merely regulating the flow through the pipe 29 by means of the valve 31.

One of the features of vthe present invention is the provision of ymeans for facilitating the examination and Withdrawal of the rods. By referring to Fig. 5, it will be seen that a pair of port holes 16 are provided in one side of the shell and like pair of aligned port holes are provided in the op- 4osite side of the shell. The aligned port oles are adapted to receive the rods 35 as shown in F lig./1. A manhole 17 is also provided as shown in Figs. 1 and 5. Thejport holes are normally closed by plugs and similarly the manhole with a cover when the mill is operating. In Fig. 1 a similar arrangement has been provided, i. e., port holes 16 and a manhole 19, said manhole being formed in a head member 6 and normally closed. U

When it is necessary to remove' the rods,

the feed to the mill is shut off, rotation stopped and the mill permitted to stand idle and assume the position shown in Fig. 1, The covers or plugs for the port holes16 are then removed and the cross bars inserted, during which time the mill is allowed to drain away the excess pulp through 'the trunnion outlet v8.' The mill is then turned 85 7. Formed in the outerface of this collar lis one-half a revolution, which leaves the rods in the position shown in Figs. 4 and 5. The manhole cover is neXt removed and an operator may then enter and remove the sec-l tional plates of the head members l2 and 13. This exposes the ends of the rods and those partly worn are withdrawn and passed through the manhole. New rods are similarly inserted and the whol'e operation of inspection Vand repair is completed in a comparatively short time interval; The head sections l2 and 13 are replaced and similarly the manhole cover. The -mill is again rotated a one-half revolution and the cross bars 35 removed. The port holes are then closed and the mill is again ready for operation.

While the valve 26 and certain features of the mill are more Yor less specific in construction, I wish it understood that variations in design and proportion may be resorted to within the scope of the appended claims, similarly that the materials and finish of the several parts employed may be such as the experience and judgment of the manufacturer may dictate or varying conditions may demand.

Having thus described my invention, what l claim and desire to secure by Letters Patent is 1 In a grinding mill of the character described, a partition member dividmg the mill into two separate grinding chambers, said partition member consisting of a ring, a head member secured on each side thereof, each head member consisting of a plurality of aligned independent sections, means carried by the ring for securing each pair of aligned sections,A and centrally disposed means for securing the head sections, said sections of one head member having a plurality of circumferentially arranged openings formed in the sides thereof, and said securing means havinga plurality of centrally disposed openings formed therein.

2. ln a grinding mill of the character described. a partition member dividing the mill into two separate grinding chambers, said partition member consisting of a ring, a head member secured on each side thereof, cach head member consisting of a plurality of aligned independent sections, means carried by the ring for securing each pair of aligned sections, and centrally disposed means for securing the head sections, said head sections of one head member having a plurality of circumferentially arranged openings formed in the sides thereof, said securing means having a plurality of centrally disposed openings formed therein, and

aligned vanes formed on the respective sec-.

tions of the head members for conveying material from one set of openings to the other.

3. In a grinding mill the combination of a rotatable hollow drum of the class described,

having rod means for grinding materiai and provided with means for lsuspending the rods as a whole within the drum, said means comprising a pair of removable, transversely positioned rods in the drum, said rods being positioned one near 'each end of the drum.

4. In a grinding mill of the character described, a partition member dividing the mill into two aligned compartments and an intermediate compartment, said partition member consisting .of a ring secured within the casing and an annular seat formed on each side of the ring, a head member adapted to bei secured with relation to each seat, one headmember having a plurality Aof circum 80 ferentially arranged radial openings formed in the side thereof and ysaid opposite head member having a plurality of centrally disposed radial openings formed therein.

5. ln a grinding mill of the character de- 35 scribed, a partition member dividing the" mill into two aligned compartments and an intermediate compartment, saidl partitioln member consisting of a ring secured within the casing and an annular seat formed on 9o each sidel of the ring, a head member adapted to be secured with relation toeach seat, one head member having a'plurality of circumferentiall arranged openings formednear the perip ery thereof and said opposite head member having a plurality of centrally disposed openings, and vanes formed between the head members for'conveying material entering through the peripherally arranged openings to the centrally disposed openings. 10@

6. In a grinding mill the combination of a rotatable hollow drum of the class described, having rod means for grinding material and provided with means for suspending the rods as a whole within the drum for the pur.- pose of removing the rods in an inoperative position, said means comprising removable transversely positioned supports in the drum.

7. ln a grinding mill, the combination of 11@ a rotatable hollow drum of the class described having rod members for grinding material, a sectional` removable partition member dividing the mill into two separate .grinding chambers, substantially as described, and means provided for supporting the rods in an inoperative position to permit removal of the rods through the sectional partition member.

8. In a grindingmill of the character described a revolvable drum, a partition member within the drum forming a pair of sepa-- rated grinding compartments, grinding means in each compartment, means for feeding material to be ground to one compartment, means for transferring the ground material through the partitionrmember to the second grinding compartment, means permitting discharge of the further ground material from said compartment, and means 13o for maintaininguniform viscosity of thet material t0 be ground during its discharge through the successive compartments, said lthe material will be gradually reduced as it pas-ses through the compartments, and means for delivering water in regulated quantities to one of said compartments 15 whereby the material will flow through both the compartments with Substantially equal mobility.

' In testimony whereofI have hereunto set my hand in the presence of two subscribing 20 witnesses.

FRANCIS DEAN BRADLEY.

Witnesses: y f

En LEMBCKE, C. W. MARLATT.

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