US981679A - Centrifugal ore-separator. - Google Patents

Description

2 BIIBETFBHEBT 1.

Patented Jan. 17, 1911.

PHILIP F. PECK, OF TACOMA, WASHINGTON.

CENTRIFUGAL ORE-SEPARATOR.

Specification of Letters Patent.

Patented Jan. 17, 1911.

Application filed March 28, 1910. Serial No, 551,919.

To all whom it may concern:

Be it known that I, PHILIP If. PEGK, a citizen of the United States, residing at Tacoma, State of \Vashington, have invented certain new and useful Improvements in Centrifugal Ore-Separators, of which the following is a specification.

The objects of my invention are to make an improved separator, employing centrifugal force and assisting agencies for separation of particles of waste and value in pulverized ores while mixed with liquid, of the general type employing a rotatable separating vessel and an expansible and contraetible internal friction element, and my invention is more particularly directed to the expansible and eontraetible washing friction element, and its associated means for effecting expansion and mutt-action of the same.

In. the drawing, Figure 1, is principally a vertical cross central section of my separator. Fig. 2, is a top plan of my separator, shown in Fig. 1. 3, is an enlarged detail of a vertical cross section of the left side of the wall of the separating vessel, the expansible element and deflector vessel, illustrated in Fig. 1, also showing some other parts, and showing the expansihle element in a state of expansion, with expansion liquid illustrated in place. Fig. l, is an enlarged vertical cross section of one wall of the expansible element, removed from the deflector vessel, showing more clearly its increased structural strei'igth toward its large end, and with the expansion chambers in a state of partial expansion. Fig. 5, is a fragmentary detail cross section. on line 5 5. of Fig. t. Fig. (3, is a 't'ragmentary detail cross section on line G(3, of Fig. 1. Fig. T, is an enlarged detail top plan of the am and some associated parts. Fig. 8, is a fragmentary enlarged sectional detail showing the water channel communicating device between the deflector vessel and expansible elen'ient.

In making my improved centrifugal ore separator, I provide a rotatable member 2, which is illustrated in the form of a vessel, and serves as a separating vessel, having a closed bottom and substantially open top. The bottom of the vessel has a central hub 3, that engages rigidly a shaft l, which is mounted in journal boxes 5, and 6, respectively, to maintain it vertically, and carries a suitable drive pulley 4. The journal box 5, is attached to the upper part of a suitable general supporting frame 7, and the box (3, is secured to the bed plate 8, of the separator; the lower end of the shaft is stepped on an anti-friction bearii'ig J, to carry its weight. The vessel 2, is turned smoothly and concentric to its shaft or axis, and on its inner peripheral wall is a separating surface 10, over which the substance to be separated passes, as hereinafter described.

The top edge or open end of the vessel is provided with an out *ardly extended flange 1l,as especially shown in Figsl and 3,which flange has an annular recess as its outer top edge, into which the depending part of a wide ring 12, is seated, this depending part being some greater in width than the depth of the annular recess 1n the flange 11, there is left between the ring and the flange, when the two are seated together, an annular space 13. The main part of the ring is made wide enough to extend inward some distance to aid the axis of the vessel as illustrated, thereby partly closing the opening in the top of the vessel.

The separating vessel is preferably made with its *alls and the separating surface inclined outward from its bottom to its top or open end, makim it of greater diameter at this end, which is the discharge end of the vessel, and the ring 12, extends a greater distance toward the axis than the extent of outward slant, or inclination of the wall of the vessel. so that the bore or opening of the ring is less in diameter than the inner diam eter of the bottom of the vessel, enabling when desired. a sutlicient body of liquid to be retained in the vessel to fill the separating passage and submerge the separating surface. 7

The ring 12, is held in place on the flange of the vessel by the screws 14, which pass through it and are threaded into the flange, as shown. This ring around its outer diameter, through its depending part is provided with a row of screw-threaded holes, eommunieating with the space 13, into which are removable screwed plugs or members 15, that are provided with small holes 16, of suitable size to permit of desired discharge of liquid and material, yet to retain a sulficient quantity of liquid in the vessel to fill the separating passage and submerge the separating surface, as above stated.

Surrounding the upper portion. of the sep arating vessel and with an annular opening in circumferential illllltllitllt with the discharge holes in the plugs 15, is supported a suitable launder 17. adapted to atch the materials and water discharged from the vessel through the holes in the plugs 15, and to flow the same through a spout 18, to be di verted thercfrmn as may be desired.

Located inside of the separating vessel 2. and with said vessel iforn'iating a separating passage is provided a member to serve as a deflector. which preferably embodies a substantial non-elastic supporting element or portion it), which is illustrated in the form of a vessel. though this part. may be any other suitable form of supporting structure. In most places in the specification I will re fer to this supporting element, as the deflector vessel. The dctlector vessel has a closed bottom, and an open top, except that at its top is a ring 21. tlanged or extended a desired distance inward toward the axis of rotation. This vessel is somewhat smaller in diameter than the inside of the separating vessel 2. thereby leaving the separating pas sage l9, adjacent to the separating surface; it is also somewhat shorter than the inside of the separating vessel, and has a central hub 22. which securely and rigidly engages the lower portion of a sleeve that is mounted in a rotatable manner around the central shaft 4.

liet ween the upper end of the hub 3, and the lower end of the sleeve 23, provided. a bearing ll, (Fig. 1,) which is preferably of an anti-friction type. This bearing is of sufficient thickness to hold the bottom of the vessels and Q0, apart, and leave a comparatively small space 95, between them, as shown.

The upper end of the sleeve 23, is pro vided with a pulley 2G, by which the sleeve with the detleetor may be revolved differentialty to the separating vessel, by means of a suitable belt (not shown) from an appropriate source of power. Around the hub 22, of the deflector, i provide a. ring 2T, which rises above the bottom of the deflector vessel, and forms a feed chamber 98. This ring. whieh I will term a feed ring. has a central opening at its top, sutlicicntly larger than the outer diameter of the hub 2'3, to leave a suitable annular space around the hub, through which liquid and material, as well as concentratc removiug water may be introduced into the feed. chamber 28, by m *ans of a pipe 29, which has branch pipes and 31, that connect respectively with suitable sources of pulp and concentrate-removing water supply.

The feed ring 27, has an outwardly ex tended flange at its lower edge, through which it is tightly secured to the deflector vessel by screws 32. Near the outer diameter of the feed chamber are provided a number of holes 33, through the bottom of the deflector vessel 20, which serve as mate rial and liquid passages from the feed chamber down into the space whence such material and liquid, actuated by centrifugal force, is driven into the separating passage, where separation or concentration takes place.

The deflector member, in addition to the deflector vessel, which serves as the supporting part or element 20, embodies an expansible and contractil'ile element 3 t, which I will term an expansiblc element, and is in the nature of a covering or jacket, secured to and supported by the dcllectiisr vessel. Thislatter element serves the office, as hereinafter described, of generating a frictional wash in the separating passage to assist in se 'iaration and in regulating the size of the separating passage. I have formed and illustrated the expansible element with its ends tlanged in toward the axis a sufficient distance to pass under rings 3.3 and ms, respectively, whieh are clamped or securely held down over these [langed ends by suitable screws or by other ordinary means, engaging the ends of the deflector vessel. The expansible element is preferably made of the general form of the outer circumferential surface of the deflector vessel, and of size to closely fit over it, and inasmuch the dellectior vessel is largest to- 'ard the top end, the expansible element is also largest in diameter toward its top end which is the discharged end of the vessel.

It. is important that the exterior circumferential surface of the expansible element during operation, should substantially conform to the contour of the separating surface without arching or bulging longitudinally, so as not, during separation, to plow or gouge the bedding concentrates from the separating surface while operating in close washing frictional relation to such bed.

in the formation or structure of the expansible element, l prefer to make it with walls that are double, or comprise double or multiple layers, as illustrated, with multiple liquid expansion chambers 37, interposed between these double walls or layers, and for this purpose. I have used layers 38, of suitable canvas, of weight and strength and of sntliciently yieldable weave to subserve the purposes desired, and have covered this can- "as with rubber to render it water tight and better adapt it to desired usage. To prevent material arching or bulging lengthwise, I have provided the outer of said layers or ullls with comparatively rigid longitudinal reinforcing means, preferably in the form of luctal strips ilfl, made up between the layers of canvas, and have sullieicully covered the canvas and reinforcing means with rubber as above stated, to produce a smooth yield able exterior friction surface.

As is illustrated, it is preferable not to llltlltt. the inner layer or wall ol' the expansible element with reinforcing means, this wall being adapted to lit around and rest against the exterior of the deflector vessel. To form divisions or partitions between the multiple expansion clu'unbers between the walls or layers, the inner wall, at desired places, as illustrated at 40, is substantially secured tothcouterwall or layer,prefcrablyin a water tight circumferential course, by sew ing and vulcaniziug, or by other suitable means of fastening, so when the outer Wall or layer with its reinforcing means is carried outward in expansion by liquid pressure in the expansion chambers, the inner wall or layer, being acted upon by this liquid, is tightly pressed against the outersu rface of the deflector vessel, over which it fits, except within :i'nd adjacent to the zone of adhesion or anchorage to the outer wall. At and within these zones of anchorage the inner layer or wall is drawn and carried outward with the outer wall and reinforcing means, as illustrated at 41, and thereby the inner wall serves, around these zones as means for binding and assisting to hold or anchor the outer wall and reinforcing means, in place on the deflector vessel, and to assist in maintaining them against torsional movement caused by washing friction during operation of the separator. The reinforcing means in the outer wall, bridge or extend across these places or zones of fastening or anchorage, between the expansion chambers on a con stant plane, and in so doing maintain a desirable even exterior frictional washing surface to the expansible clement.

As the expansion elementbecomes contracted, there is something of a tendency to stretch a small portion or excess of the part of the inner wall around its zones of anchorage to the outer wall, into a wrinkle, and to accommodate this excess or wrinkled portion, so that it will not unduly press against the outer surface of the deflector vessel and tend to make an uneven place, or to wear rapidly, I provide a suitable recess or groove 42, in the outer walls of the deflector vessel into which itmay rccede.

On the inside of the deflector vessel, for each of the expansion chambers, I have provided an annular trough 43, which is formed by providing rings 44 and 44, in the defiector vessel, extending a desired distance inward toward the axis of rotation. These troughs serve as facility for supplying liquid to the expansion chambers. To sup ply liquid to these annular troughs 43, I

have provided a suitable pipe '15, held in place by a bracket lb. 'lhis pipe has two bralu'hrs ll, and lo, each ol which oonuuunicates with one ol the troughs l l. Around in the bottom ol those troughs, through the wall of the dcllenlor vessel and through the inner wall or layer of the expansihlo cle nicnl, are provided passages -17, eonununieating with the respective expansion chambers, so that water from the troughs 4?), may pass into the expansion chambers during o nxration, and actuated by centrifugal force, become expansion liquid with sutlicient pressure to expand the chambers and corre- Espondingly enlarge the expansion element diametrically, as desired, carrying the outer surface to comparatively close proximity to the separating surface, and thereby rendering the separating passage of minimum desired sizes for con'n'nencement of concentration.

The pressure to which the liquid in the expansion chamber is subjected at a predetermined speed of rotation of the deflector vessel, mainly depends on the amount of liquid maintained in the troughs 48, from the fact that such liquid forms the column or body, which, acted upon by centrifugal force, effects a hydrostatic pressure substantially proportionate to its depth.

It is intended that the treatment vessel alternately accumulates a bed or load of concentrates of sutlicient size to largely fill the separating channel with the expansible ele ment fully contracted, and then to discontinue separation and to discharge such accumulated concentrates. To enable this resuit the separating vessel, during the concentrating period is rotated at a suitable high rate of speed to produce the requisite centrifugal force, and the deflector is rotat-ed at a required different speed to produce frictional wash, through differential travel of the expansible element and separating surface, of intensity necessary to constantly move or wash the lighter or waste part of material from the separating surface, while permitting the heavier parts, or concentrates to lodge and bed on such surface.

It is necessary during concentration, in order to secure a condition to satisfactorily accomplish separation, to have and maintain the separating surface, or the surface of the bedding concentrates, and the frictional surface of the expansible element in comparatively close operative proximity, which is the condition obtained by expansion of the friction element, and this condition is maintained throughout the loading period by gradual contraction of this element, as hereinbelow described.

It is obvious that after being expanded to render the separating passage suitably small for ('om'entration, at the. beginning of the loading period, i'l this element was not ol :1 nature that enabled progressive contraction during the loading period, the small passage initially produced 'l'or separation would soon become filled and prevent l'ur ther coneentratiiin. To best enable gradual contraction oi the expansible element to gradually and. progressively provide space for the bedding concentrates after they become separated, and still. maintain its necessary close operating relations to the sur face on which concentration is effected, l have provided means for gradually removing the liquid from the annular troughs 43, in the deflector vessel, thereby gradually decreasing the expansion pressure within the expansion chamber. To remove this liquid, I provide a suitable pipe or conduit is, with branch pipes 49 and 50, the branch 50, being formed by bending the lower end of the conduit pipe 48. These branch or scoop pipes are located with their scooping ends directly against the course of rotation, of the liquid in the troughs, to operate in contact with the surface of this liquid, so that such liquid is scooped out and removed to the extent that the ends of the scoop pipes are moved toward or from the axis of rotation of the vessel. This conduit pipe is suitably supported by the part 51, in a manner to permit of rotating movement, and its upper end extends out and over the top of the vessel, where it may connect with hose, (not shown), or any other appropriate means of delivery of the liquid removed.

As means of changing the position of the scoo iiing ends of the scoop pipes, and of traveling them toward and from the axis of the vessel, thereby governing the amount of liquid in the troughs 43, I provide a cam rotatably supported on the bracket 51, and to the cam, have connected a worm wheel 54, engaging a worm 55, mounted on a shaft 55, journaled in position to revolve the worm wheel. On the shaft 55, of the worm I mount a pulley 56, in position to be driven by a belt 57, communicating with a pulley 58, which is carried by a shaft 59, supported in suitable journal boxes 60, and 61, which engage brackets from a part of the frame of the separator. The shaft 59, also carries a pulley 62, in position to be driven by a belt 63, engaging a pulley 64, on the shaft 4, of the separating vessel, so that through these several agencies the cam is rotated as the separating vessel is revolvcd.

The upper end or portion of the scoop pipe is crooked in position to carry a clamp 65, (best illustrated in Fig. 7), which is pro vided with an adjustable screw 66, the end of which contacts with the periphery of the cam 52, and the scoop pipe is consequently moved or swung in a rotary direction, as the can! is revolved, govcriied by the peripheral contour of the cam; the spring 67, which is lixed in a. manner to press against the bent end ol the scoop conduit or pipe, serving to hold the end of the screw 66, against the peripheral surface of the cam.

'lhe scooping ends oil the scoop pipes are shaped and in position with relation to the can], and the peripheral contour of the cam is also termed so that removal of the liquid il 'ro1n the annular troughs .43, in the deflector vessel is suitably timed and n'oportioned during the loading period, to enable contraction of the expansible element, as desired, for maintaining suitable separating conditions and at the same time to accommodate the bedding concentrates in the separating passage, and also to effect desired expansion during the unloading period. The position of the scooping ends of the scoop pipes may be somewhat adjusted by the screw 66.

The resistance to expansion, and the contraction of the cxpansible element is principally effected by the pressure of liquid against its exterior, while such liquid is flowing through the separating passage, but is partly occasioned by the structural resistance to expansion or stretching of the expansible element.

The pressure of the liquid within and flmving through the separating passage is the greatest near the feeding end of the vesscl, and gradually decreases toward the discharge end, from the fact that the distance of flow through the separating channel and consequent frictional resistance to such How and the requisite static pressure to overcome such friction, decreases in that direction. It therefore follows that the resistance to expansion of the expansible element by outside pressure is less toward the dischar e end of the vessel, and in order to assist 1n maintaining a uniform degree of expansion throughout the length of the expansible element under such decreasing pressure, I form such element of greater strength and having greater structural resistance to expansion toward the discharge end, which increased strength and structural resistance is intended to make up or compensate for the lesser external resistance or pressure toward the discharge end channel, and thereby facilitate uniform expansion. From the further fact that the separating vessel is larger in diameter toward the discharge end, and the deflector vessel, as well as the expansion element is correspondingly larger at this end, there is, at this end an additional centrifugal stress, because of the greater diameter, and a resultant increased tendency to expansion, and it is further desirable to here make the structure of the expansible element of greater strength on this account.

As is illustrated more clearly in Figs. 3,

4, 5, and (3, I have formed the outer Wall 01' layer of the expansible element with progressively increasing strength toward the discharge end, which is also the larger end, by inserting additional layers of canvas within this wall. As illustrated in Figs. 4, and 5, at the lower end of the expansible element, there are but two layers of canvas made up in the outer wall, and at the discharge end there are four layers used, as shown in Figs. 3, and 6, which must increase the strength and its resistance to expansion at this end. One of the additional layers of the canvas is extended down below the center, and the second additional layer cxtends a considerable less distance downward, so that the increased strength is progressive toward the discharge end. In expansion of this element, its structural resistance becomes greater. as its stretching or distention increases and in such proportion there is required a progressively greater expanding liquid pressure within the expansion chambers, and a greater accun'iulation of liquid within the troughs 43, to effect such required increased pressure, and furthermore, in contraction of this element it follows that as contraction proceeds, the required resisting pressure to such contraction decreases progressively as the resistance to expansion decreases, therefore to obtain uniform speed of contraction, the expanding liquid within the troughs 43, should be removed at a constantl y increasing rate, to effect such decreas ing expansion pressure as the expansion element becomes less tense. To accomplish this variation in degree or speed of removal of liquid from the troughs l3, 1 have formed the contour or peripheral surface of the cam with an increasing degree or ratio of diversion in relation to its arc, throughout the portion of its circumference that operates to move the scooping pipes l9 and .50, for removal of the liquid in the troughs -13. I have illustrated the cam in Fig. 7, detached and enlarged in plan, and have indicated in dotted line, what would be a uniform or constant divergence of a part. of its periphcry with respect to its are, which illustrates the contrast to my present structure of cam.

It will be understood that the movement or travel of the scooping end portions of. the pipes 49 and 50, is adapted to be in a direction from the axis of the separating vessel at an increasing rate, and that the cam, having a peripheral contour of the form above described, serves as means for effecting such travel at an increasing rate, thereby removing the expanding liquid in such manner, which results in decreasing the expanding pressure in a similar ratio. This travel and its resultant effect is produced automatically and at a progressively increasing rate, being the sequence of the operation of the cam having the form described.

During operation, there may be accidentally, through breakage or leaking of the inner wall of the expansible element, some liquid between the outside of the deflector wall and the inner layer or Wall of the expansiblc element, and to permit of its esca e and removal I provide a fixed conduit 68, in the nature of a pipe, with one end crooked in close position to the inner wall of the de- Hector vessel, adapted to scoop any such liquid from the deflector vessel that may come through the passages 69. This pipe 68, is supported and held in place by the bracket 51, and its upper end is extended outside of the separating vessel.

In operation, the separating vessel is 1'0- tated at a. sufficient speed to'develop the high degree of centrifugal force required to retain the concentrates on the separating surface, and the deflector is rotated at a. sutliciently different speed to enable the expansible element, through travel differential to the separating surface to create a washing or liquid scouring friction sufficient to wash and keep the waste substances moving to discharge while the concentrates accumulate in a bed on the separating surface. During this time pulp in a sufliciently dilute state, and in sufiicient quantities to form a. body in the separating vessel to fill the separa ting passage and submerge the separating surface, is introduced, and there is also sufficicnt liquid introduced into the troughs in the deflector Vessel, to expand the expansible element as desired. As the operation proceeds the cam mechanism operates the conduit or main scoop pipe 48, swinging the latters branch scoop pipes 49 and 50, which lessen the expanding pressure and enables the expansih-le element to be gradually forced inward, or contracted, afiording space in the separating passage for bedding of concentrates, until the expansible element has become fully contracted. \Vhen the expansible element has become fully controlled, the flow of pulp for separation is stop ed, through use of a valve the speed 0 rotation of the vessel is lessened; preferably clean concentrate-removing liquid is introduced to the vessel, by opening the valve 71. The coneentrate-removing liquid is enabled to remove the concentrates, because of the comparatively low speed at which the separating vessel is rotating and also because at this time expansion liquid is again in the troughs 43. This accumulation is again permitted by reason of the position which the scoop pipes have at this time assumed, through tolerance of the cam in its rotation, so the cxpansible element has become under full expanding pressure. As a result of these changed conditions from those prevailing fol-concentration, the accumulated bed or load of concentrates in the separating passage is quickly dislodged and driven to discharge, leaving the separating vessel free for another period of concentration. The concentrating speed of rotation of the separating vessel is restored; the flow of concentrate-removing liquid discontinued and the flow of pulp again restored for separation, and the operations are successively rcpeat'ed.

\Vhat I regard as new and desire to secure by Letters Patent is:

i. In a centrifugal ore separator, the combination of a rotatable member forming one wall of a separating passage adapted to contain a body of liquid while in operation and a member difl'erentially rotatable thereto in part forming said separating passage, the second member embodying a comparatively rigid supporting element and an element with expansible and eontractible walls adapted to increase in resistance to diametrieal expansion to 'ard the discharge end of the separating passage, substantially as de' scribed.

2. In a centrifugal ore separator, the combination of a rotatable member of greater diameter at one end, provided with at separating surface and forming one wall of a separating passage adapted to contain a body of liquid in operation and a member ditl'erentially rotatable thereto of greater diameter at one end in part forming said separating passage, the second member embodying a conqraratively rigid supporting element and an expansible and cont 'actible element oi? greater diameter at one end adapted to increase in resistance to diametricat expansion toward said large end, substantially as described.

ii. In a centrifugal ore separator, the combination of a rotatable member Forming one wall of a separating passage adapted to contain a body of liquid while in operation and a member dilicrentially rotatable thereto, in part forming said separating passage, the second member embodying a comparatively rigid supporting element and a diametrically cxpansiblc and contractible element anchored to the supporting element adjacent to its end, and in part intermediate between said ends and containing eon'iparatiyely nonelastie reinforcing means within said expansible and eontractible 'all, extending across the zone of said intermediate an- ':horagc, substantially as described.

2. in a centrifugal ore separator, the combination of a rotatable member provided with a separating surface. forming one Wall ot a separating passage adapted to contain a body of liquid while in operation and a member dill'crentially rotatable thereto, in part forming said separating passage, the second member embodying a comparatively rigid supporting element and an element with walls having multiple yieldable layers with anexpansion chamber interposed between said layers, the outer ot said layers structurally adapted to increase in resistance to dianu-trical expansion tovard the discharge end of the separating passage, substantially as described.

5. ln a centrifugal ore separator, the combination of a rotatable member forming one wall. of a separating passage adapted to contain a body ot liquid while in operation and a member ditlcrcntially rotatable thereto in part. forming said separating passage, the second member cmla'ulyin a comparatively rigid supporting element and an element with walls having multiple layers with multiple expansion chambers interposed be tween them. divided by anchorage zones of said multiple layers, the outer one of said layers being provided with comparatively non-elastic reinforcing means extending across said anchorage zones, substantially as described.

(3. In a centrifugal ore separator, the combination of a rotatable member having a separating surface, forming one wall of a separating passage adapted to contain a body of liquid while in operation and a member ditl'erentially rotatable thereto adapted to be expanded and contracted during operation increasing in dianu-tcr toward its discharge end. embodying yieldable layers with an expansion chamber interposed between said layers, the outer of said layers st1ructurally adapted to increase in resistance to diametrical expansion toward the discharge end of the separating passage, substantially as described.

7. ln a centrifugal ore separator, the combination of a rotatable member forming one wall of a separating passage adapted to contain a body of: liquid while in operation aml a member ditl crcntially rotatable thereto in part forming said separating passage. the second member embodying a comparatively rigid supporting element and an element with walls having multiple layers with multiple expansion chambers interposed between them, divided by anchorage zones of said multiple layers, the outer one of said layers being provided with comparatively non-elastic reinforcing means extending across said zones of anchorage and the outer of said layers adapted to increase in resistance to diametrical expansion toward the discharge end of the separating surface, substantially as described.

8. ln a centrifugal ore separator, the coinbi nation of a rotatable member forming one wall of a separating passage, adapted to contain a body of liquid While in operation, a member dili'erentially rotatable thereto in part forming said sepaaiting passage, the second member embodying a comparatively rigid supporting element and. an expansible element with Walls having multiple layers with an expansion chamber interposed between said layers, said supporting element provided with liquid containing chambers having liquid passages to said expansion chambers, and having liquid passages from between the exterior of said supporting element and the interior layer of said expansihle clement, gradually travelable means adapted to remove liquid during operation from said liquid chainher within the sup porting element and comparatively lixcd means adapted to remove liquid delivered from between the outer surface of the wall oi the supporting element, and the inner layer of the expansihle element, substantially as described.

9. In a centrifugal ore separating frie lion element adapted to he diametrically expanded and contractedZduring operation, the combination of walls having multiple layers with multiple expansion ohami crs inici'posed hctuecn said laye s, the layers acing anchored tt e'ether at th: ZUIW of tliri ion hetncen said chainhers and comparatitely rigid reinforcing means Within the l l l l outer layer bridging across said zones'of anchorage, on a comparatively constant plane during expansion and adapted to carry the inner layer outward within said zone while inaintainin such constant plane, substantially as descri ed.

10. In a centrifugal, ore separating fric tion element adapted to he diametrically expanded and contracted during operation, the combination of Walls having multiple layers with multiple expansion chambers interposed between said layers, the layers heing anchored together at the zone of division between said chambers, the outer of said layers increasing in structural resistance to expansion toward its discharge end and coinpa 'atively non-elastic means adapted to reinforce the outer of said layers ex tending across the zone of said anchorage, substantially as described.

N. W. COLLINS, JOHN G. CAMPBELL.

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