US1294864A - Ore-treating apparatus. - Google Patents

Description

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, APPLICATION FILED AUG-27, I917- 1,294,864. Patented Feb. 18,1919.

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WITNESS: Q Q INVENTOR. 3W AL. B/Omf//d ATTORNEY.

A. L. BLOMFIELIL ORE TREATING APPARATUS.

APPLICATION FILED AUG.27, 19!]. 1,294,864

. Patented Feb. 18, 1919.

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INVENTOR A L. B/omfi/d 30 factor to automatically ALFRED LESLIE To all whom may concern:

' a subject. of George V,,King of England,-

Be it known that I, ALFRED L. BIDMFIELD,

residing at Denver, in the county of Denver and Stateof Colorado, have invented certam new and useful Improvements in Ore- Treating Apparatus, of which the following classifier and the is a specificatlon.

method of grinding ores in a closed circuit,

Th s invention relates to improvements ore-treating apparatus, its primary object being to provide ina closed circuit grinding system, means to automatically regulate the feed of fresh material in proportion to the resistance presented by the material under treatment, to the movement of the opera-I tive parts'of the apparatusincluded in the. p Y 'I des1re-1t understood, however, that my system.

It is a well-known fact that in the present the return feed to th mill out-' e grindin weighs the original that this return feed unless carefully regudischarge by lated, is liable to exceed the maximum capacity of the mill.

As the load increases, the resistance to the movement ofthe operating parts of the mechanism by whi'c the alternate classification and grinding of the ore is effected, increases proportionately, and in the present inventionadvantage is taken of this definite regulate the original feed to the mill and thereby maintain the circulatin load at or greatest e ciency.

The closed circuit to which my invention is more particularly applicable, includes a classifier, a grinding machine, a device for feeding fresh material into said machine, a

conveyance for the discharge from the,

grinding-mill to the classifier, and a-conveyance for returning the oversi'z e from the classifier into the mill.

The-separation of the sizes isobtained in the classifier by the subsidence'of the heavier and coarser particles out of'the liquidinass,

while the fines are held in suspension and re- .moved by overflow.

, The settling matter is moved to a. point of the action of a rake or other suitable mechanical contrivance and it is by .the resistance tothe operation of this contrivance that in the preferred form of my invention, the original feed'to the grinding mill is regulated.

It will be readily seen that the regulation BLOMFIELD, 0 DENVER,

COMPANY, A gom'om'riolv or DELAWARE.

oRE-rnm'rme nmmnarus.

- Specification of Letters Patent. f Application and August 27, 1917. Serial No. 188,468.

shown two-methods -descr 1be d ob]ects' either mechanlcally by an association of cooperative mechanlcal decaljly. operating feed severa times andwhich the milling plant is near the point'of its cr mes. 1

COLORADO, ASSIGNOR 'rnE DORE of the feed to the mill in order to avoid a load exceeding the capacity the opportunity of-constantly maintaining the mill at or near the point of its greatest efficiency; that the regulated feed to the mill produces a regulated feed and that in consequencethe are likewise promoted.

In the accompanying drawings'I have of attaining the abovevices, or electrically by the use of automaticircult-controlling appliances;

invention is not limited to the use of any particular device or devices tion and arrangement thereof is subject to many variations and modifications not only by reason ot the wlde range'of appliances whlch are sultable for the purpose, but also on account of the differences in the construction and arrangement of the elements of composed. In the drawings in the various views of which like parts are similarly designated,

Figure -1 represents a plan view of a closed circuit method of applying my invention by mechanical means,

Fig. 2, a sectional elevation on'a .plane indicated by the line 2+2, Fig. 1, Fig. 3, a plan view of the system showing a method of applying to accomplish the desired result inasmuch as the construcgrinding s'ystem showing the.

Patented Feb.'1 8, 1919.

thereof, afl'ords .to the-classifier efliciency of the uniformlty of its product my invention by the V use of an assoclation of electrically controlled devices, and

F Fig.. a section taken along the line 4-4, ig. 3. 'Beferrin first to Figs. 1 and 2 of the drawings t e reference character 2 designates a classifier the construction of which will be hereinafter more fully described, 3 a grinding machine of the ballor tube-mill type, and 4 a feeding device consisting of a rotary disk 5 mounted beneath a' supplyhopper 6.

The material discharged from the disk of the feeding apparatus is conveyed through a pair of chutes 7 into a box 8 from which it is lifted intothe means of a rotary scoop 9.

The ground product of the mill is by ball-mill by means of a chute .10 conveyed to the feed end of the classifier and the coarse product or oversize discha ed from the latter through an outlet 12, isby means of a chute 13 returned to thebox 8 and fed into the ball-mill with the material delivered by the feeding apparatus. i

I desire it understood thatthe system of devices shown in the diawingsand herein described, is merely illustrative of one or the many uses to which my invention may be employed, and that the effective operation of the automatic feed regulatln appliance hereinafter to be described is in epend and a passage 16 in the center of the sloping bottom of the container, discharges the set tling coarser constituents of the material into the subjacent end of a trough-like box 17 which constitutes the secondary settling and dewatering chamber of the classifier.

The bottom 19 of the trough slopes from its feed-end upwardly to a point above the crank-wheel 22 on a liquid level, determined by the overflow of the initial settling chamber, and a conduit 18 supplies in the operation, liquid to the trough for the urpose of producing a countercurrent whic returns the fines rising out of the material in the secondary chamber, into the primary chamber for reclassification and thus assists in effecting a clean separationof the two classes into which the orepup is divided.

uitable mechanisms are provided to mechanically impel the material across the bottom of the chamber 14 toward the outlet 16 and along the sloping bottom of the trough 17 toward the outlet 12 which connects with the chute 13.

The mechanism for moving the material upwardly along the bottom of the dewatering chamber, consists in the construction shown in the drawings, of a pair of rakes 21 which are suspended for reciprocation and which are cooperativel connected with a di'iving shaft 23 by means of a pitman 24.

The mechanism which impels the material settling in the chamber 14, across the bottom thereof toward the passage 16, is composed of a series of sweeps 25 projecting from the lower end of a shaft 26 which-.is rotatably sup orted in boxes 27.

T e shaft 26 is in the operation of the classifier slowly rotated by a worm movement consisting of a toothed wheel 28 and a worm 29 on a transversel extending shaft 30, which meshes with sai wheel.

For the purpose of adapting the driving mechanism of the shaft for the actuation o the automatic feed-regulating appliance, the

usual thrust bearing of the worm shaft is i replaced by a bearing 31 which supports the shaft for rotation and permits of a limited lon 'tudinal movement of the same.

he-worm-shaft engages at one of its ends with the head 32 of a thrust-block 33 slid- 1 ably mounted with relation to an abutment 34-which b means of bolts 35 is connected with the caring 31 which supports the worm-shaft.

A coiled-spring 36 disposed between the sliding thrust block and the abutment, provides a resilient'element which yieldingly opposes endwise displacement of the wormshaft when the resistance ofl'ered by the settled material on the bottom of the chamber 14 to the rotar movement of the sweeps, increases beyon a predetermined degree.

It is this resistance to the o eration of the mechanism provided to impe the material settlin upon the bottom of the primary set tling c amber, toward the outlet of the same, that is utilized for the operation of the a liance which automatically regulates t e eed to the inding mill.

This app iance consists in its preferred form, of a baflle 37 which extends above the rotary disk 5 of the feeding device and which 'is mounted for mngitudinal adjustment upon a suitable support designated in the drawings by the reference'numeral 38.

The baflle is fixed at the end of a rod 39 which at its opposite extremity is pivotally attached to one of a, pair of bell-cranks 40. and 41.which are connected for synchronous motion by means of a rod 42.

The lower bell-crank of the pair is by means of a transverse arm 43, connected with the sliding thrust-block 33, with the result that when b an increased resistance to the movement 0 the mechanism which impels the settling solids toward the front of the chamber 14, the worm-shaft is longitudinally displaced, the conse uent movement of the thrust-block against t e ressure of the spring, compels the connecte bell-cranks to turn about their respective axes, and causes the baffle to recede from the center of the feed disk.

The bafile serves in the operation of the feeding'mechanism, to obstruct the movement of the material. delivered by the hopper 6 onto the rotating disk 5 and thereby comjEST AVAILABLE COrpels it to discharge over the edge of the disk into a chute 7. It will be readily seen that the quantity of material thus delivered from the feed-disk, varies in relation to the extent of the bafile above the same, and that by moving the baflle in the direction of the center of rotation of the disk, the quantity of material fed across the edge of the latter is proportionately increased.

In the operation of the classifier,- the material subsiding in the primary settling chamber, congregates upon the bottom thereof in a semi-solid condition and is by the rotary movement of the sweeps 25, moved toward the passage 16.

If by an increased discharge of material from the grinding mill, the quantity of settling matter collecting on'the bottom of the chamber 14, exceeds an amount predetermined by the tension of the spring 36, the consequent resistance to the rotary movement of the shaft 26 acts immediately upon the regulating appliance hereinabove described and causes the battle to recede from the center of the rotating disk and thereby diminishes the feed into the ball-mill, in profportion to the excess delivered to the classi- In the form of my invention illustrated in Fig. 3, the feed to the ball-mill 3 is regulated by a system of electrical devices in proportion to the resistance of material settling tothe bottom of the secondary settling chamber, to the impellent movement of the rakes 21.

The driving shaft 23 of the mechanism which imparts a reciprocating motion to the rakes, is provided with a pulley for its connection with an electric motor 46.

The feed hopper 6 dischar es onto the end of an endless .belt-conveyer 4t mounted upon rollers 48 on a pair of shafts one of which 49 is by means of a belt 50 connected with a second electric motor 51.

An ammeter 52 connected in the circuit 59 of the first-mentioned motor, has a circuit breaking appliance including a stationary contact 53 and a blade 54 adapted to be moved into engagement therewith by the movement of the hand 55 when the amperage of the current passing through the circuit exceeds a predetermined amount.

The blade and the contact of the circuitbreaker are connected at opposite sides of I. break in a shunt of the main circuit which controls the operation of a second cir- :uit-breaker 'which in its preferred' form =onsists of a solenoid 56 and a pair of conacts 57 which under normal conditions are lectrically connected by a bridge 58 on the reciprocating armature thereof.

The contacts are connected at opposite .des of a break in the circuit 61 of the mo- )r 51 which impels the feed-belt.

' This circuit includes a shunt 62 which is connected to afford a pasage of current around the break in the main circuit and which contains a resistance-coil 63.

\Vhen by an over accumulation of settled matter on the bottom of the secondary set tling chamber, the resistance to the driving action of the motor 46 is increased, the consequent rise in amperage of the current which operates the motor will'cause a movement of the hand 55 of the amineter, with the result that the therewith associated circuit-breaker completes the shunt-circuit 60 in which it is connected.

The closingof the shunt circuit energizes the solenoidof the second circuit breaker which by the movement of its armature disconnects the contacts 57 and thereby discontinues the current flow through the line of the circuit of the motor 51 which operates the feed-belt.

The current is thus compelled to pass through the shunt 62 and the resistance coil 63 included therein with the result that the current-flow through the motor 51 is retarded.

The reduced current-flow lessens the rate of rotation of the motor shaft and thereby retards the movement of the feed-belt and proportionately reduces the feed into the all-mill.

Having thus described my invention and the simple illustrative methods of carrying it into effect by either electrical or mechanical means, it will be readily understood that these means may be varied in construction and relative arrangement in accordance-with the character and construction of the apparatus to which the feed-regulating contrivance is applied. 1

Having thus described my invention, what I claim and desire to secure .by Letters-Patent is:

l. The combination with apparatus for eomminuting and classifying ores, connected in a closed circuit, of mechanism for regulating the feed to said circuit by a resistance of the oversize of material under treatment,

to its movement in said circuit.

2. The combination with apparatus for comminuting and. classifying ores, connected in a closed circuit, of mechanism for regulating the feed to said circuit in proportion to the resistance of the oversize of material under treatment, to its movement in said circuit.

3. The combination with apparatus for comminuting and classifying ores, connected in a closed circuit, of mechanism for reducing the feed to said circuit, in proportion to the resistance of the oversize of material under treatment, to its movement in said circuit, said mechanism including means for deferring its operation until the resistance has increased beyond a predetermined de- 4:. The combination with an apparatus for the comminu-tion of ores, and an appllance for feeding material thereto, of means to eflect a return flow of an oversize of ma-- terial under treatment, to said apparatus, and mechanism for regulating the feed by said, appliance, by a resistance ofthe 0ver-. size'to its said return movement.

5. The combination with a grinding-mill and a classifier connected in a closed circuit, an appliance for feeding material to said circuit, and means to effect the return flow of material dischar ed from the classifier to the mill, of mec anism regulating regulating the feed by'said appliance, by a resistance of thedischarge to said return movement;

.- 7, In combination,- a'grindin'g mill and a classifier connected in a closed circuit, said creased beyond a predetermined de ree. In' testimony whereof I have a Xed myclassifier including an overflow forfines, an appliance for feeding material to said circuit, impellent mechanism to efiect the mute .ment of the oversize toward the mill, and means for regulating the feed by said'appliance in proportion to a resistance presented by the oversize to the operation of said mechanism. a

'8. In combination, a grindingmill and a classifier connected in a closed circuit, saidclassifier including an overflow for fines,-an4

appliance for feeding material to saidcir.'-

cuit, impellent'mechanism to effect the movement of the oversize toward the mill, and

means for reducing the feed bysaid appliance 'in proportion to the resistance pre-I sented b saidmec anism after sald reslstance has 1nsignature in presence of two witnesses.

the oversize to'the'operation' of I:

ALFRED- LESLIE BLOMFIELD.

I Witnesses:

A. DLFREEDMAN,

L. RHoAnEs.

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