US2014291A - Mineral separator - Google Patents

Description

Sept. 10, 1935. J. w. REEDl MINE-RAL SEPARATOR FiledApril 28, 1934 2 Sheetssheet 1 Sept. l0, 1935. J. w. REED I MINERAL SEPARATOR Filed April 28, 1934 2 Sheets-Sheet 2 v l gmwrw L/ Reed a@ im f kan fm,-

Patented Sept. 10, 1935 UNITED STATES PATENT OFFICE is` claims. (ci. 209-475) My invention relates to ore or mineral separators and particularly to that class of separators wherein pulverized or granular ore is actedv upon by jets or puffs of air, or other iiuid in such a manner as to separate the lighter from the heavier grains, the lighter portions being carried to the top, allowing the heavier grains to settle vto the bottom. l

A device of this character comprises generally a separator chamber having a perforated bottom, means' for feeding the material thereto, means for projecting jets or puis of air or other uid upwardly through the perforated bottom to stratify the material resting on said bottom,

l5 the lighter material being carried to the top, al-

lowing the heavier material to settle to the lower stratum;l and means for conducting the heavier and lighter portions from the device through separate channels. Such a device is emcient 2() when designed and proportioned to handle or of a uniform richness and constant'speciiic gravity of its component parts, but does not accommodate itself to variations in the specic gravity or richness of the ore.

Pulverized ore, generally speaking, consists of -valuable portions which are usually of a greater specic gravityjand particles of a lighter speciiic gravity which have little or no value. In practice, the proportions of the heavier and lighter partsof the ore vary; and thereforein order that'the separate 'valuable portion of the ore shall be of .uniform richness, means must be provided/for A,automatically compensating for vthe lvariations in richness of the ore as it passes through the machine. Furthermore, the ores to` be "operated upon will vary in their known or expected specific gravity or richness, and `therefore, means should'be provided for initially determining the said richness, and for adjusting the device to operate on the same to the desired degree of perfection. s

The object of this invention is to provide a device of the class mentioned by means of which the valuable portions of the ore may be delivered in a uniform degree or percentage of richness,

irrespective of any variations in the richness of the ore.

l A further object of this invention is to proto operate'upon the ore to separate the valuable portions at a desired degree of richness or perfection.

A further object of the invention is to provide means whereby when the device is set to operate, 5

on an ore of known or expected richness, it willautomatically adjust self to varying characteristics of the ore, both as to richness and density, so as to deliverthe heavier particles proportionately to their rate of accumulation. 10

A further object of my invention is to providein a device vof the class mentioned, means whereby the varying richness, determined by its specic gravity, will be continually recorded during the operation of the device. 15

A further object of the invention is to provide means for preventing the lighter portions of material from entering the discharge conduit provided for the heavier portions.

A further object of the invention is to pro- 20 vide means for automatically relieving the air pressure in theair chamber and consequently the degree of agitation, upon the accumulation or" an excess of lighter material in the separator.

A further object of my invention is to provide 25 a construction and arrangement of parts lwhereby the degree of agitation in the separator chamber shall be automatically varied in prov portion to the volume accumulated therein.

A' further object of the invention is to provide 30 means whereby the device willr automaticallyl start into operation when the ore is fed thereto and which will stop when the feeding of the ore ceases. Other objects will appear hereinafter.

With these objects in view my .invention con- 35 sists generally in mounting the separating chamber and related parts for limited vertical move` ment due to the weight o! the material therein, together f with means associated and movable therewith for determining the specific 'gravity 40 of the material fed thereto. Preferably the separating mechanism is mounted upon a balance beam having a. tare weight to counterbalance the same. The means .for determining the specific gravity of the ore as it is fed to the device 45 comprises a compensating chamber supported above the separating chamber .and having sloping sides and open at the bottom, means for delivering material to the compensating chamber in a uniform degree of compactness, and a pendulum connected to the beam to hold the device at rest after having moved to a position due to the weight of material in the compensating chamber. The invention further contemplates the provision of a recording device in comber.

vas mentioned in which the lower end of the disbination with the above arrangement whereby the attendant for the machine may at a glance determine the speciiicgravity of the material being fed to the machine at any time.

My invention further consists in providing a device as above mentioned, further characterized by a compensating chamber above the separator chamber and movable therewith and a feed chamber directly above the compensating chamber and having'its lower end extending into the latter, said feed chamber having steeply sloping sides so as to deliver the pulverized ore to the compensating chamber in a uniform degree of compactness. My invention further consists in a device as mentioned in which the compensating chamber and the feed chamber are both hopper shaped with steeply inclined walls and provided with discharge orifices at their lower ends, the discharge orifice of the compensating chamber being smaller than the orifice of the feed chamber whereby a quantity of material of uniform compactness is maintained within the compensating chamber to the level of the feed chamber orifice.

The invention further includes an adjustable l counterpoise for the balance beam whereby the when tilted by the presence of material therein to close a circuit to the fan motor, and to open said circuit. when free of material. My invention further consists in a device as mentioned in which y the separator chamber is provided with a centrally disposed discharge orifice for the heavier material, communicating with a depending discharge conduit, in combination with means supported within the separator chamber to prevent thelighter portions of the material from entering said discharge conduit. My invention further consists in such a combination and arrangement of parts that the accumulation of heavier material in the discharge conduits con- Stitutes a valvefor maintaining the air pressure in the air chamber, and which, whensaid material is discharged due to the augmented weight of material, will permit escape of a portion of the air so as to vary the air pressure in said air cham- My invention further consists in a device charge conduit from. the separator chamber is provided with a normally closed valve, said valved end being opened moreior less according to the volume of material of heavier specific gravity in the device.

My invention further consists in various details of construction and arrangements of parts' al1 as will be fully described hereinafter and particularly pointed out in the claims.

My invention will be more readily understood by reference to the accompanying drawings forming a part of this specification and in which- 5 Figure 1 'is a side elevation of a separating device embodying my invention in its preferred form, parts being shown in section,

Fig. 2 is a vertical section on substantially the line 2 2 of Fig. l, and

Figs. 3, 4 and 5 are detail illustrations of the separator chamber illustrating the different POSitions thereof relative to the accumulation of material therein. Y

Referring now to the drawings, I Aindicates generally a housing for the apparatus which may be of any desired form so as to properly support the various parts and to protect vthe movable portions from outside iniiuences. 2 indicates the outer casing of the separator which is provided with a hopper bottom 3 having a central discharge opening 4 communicating with a chute 5 fixed to" said bottom. The chute 5 empties into a xed discharge chute I extending through the side of the housing I. The upper end of the casing 2 isopen and extends into a dust hood 'I fixed within the upper portion of the housing, as will be more fully described hereinafter.

Supported in a suitable manner within the lower portion of the casing 2 is a separator cup 8 having a hopper bottom 9 terminating in a vertical, centrally disposed tubular discharge conduit I 0. The separator cup is of less diam- 'eter than the casing 2 and is centrally disposed within the same, thereby forming an annular space 2" between them, which constitutes a passageway for the lighter portions of the ore as they are discharged from the cup 8. A perforated plate II is arranged within the cup 8 and divides the same into an upper separating chamber I2 and a lower air chamber I3. The plate II is hopper shaped and empties into a central Ivertically disposed conduit I4, which extends concentrically into the upper end of the conduit I 0. The conduit lI Il, below the lower end of conduit Il, is somewhat contracted in cross section and terminates in a trough shaped bottom I5which directs any material accumulating therein to aK lateral discharge orifice I6 formed in the side of the conduit I at its, lower end. This orifice at its upper end is substantially the width of the conduit and tapers downwardly In conformity with the trough shaped bottom I to facilitate the dis;- charge therefrom. The lower end of the conduit I0 extends into a discharge chute I1 which chute extends through the. side of the housing,

as indicated in-Fig. 1.

The casing 2 and .its contained parts are supported for limited vertical movement, as by a balance beam mounted upon alfulcrum shaft I 8 having bearings in suitable lbrackets I9. One arm of the beam comprises a yoke 20, the free ends of the yoke being connected to lugs 2| fixed to the sides .of the casing. The other arm of they A beam comprises a graduated bar 22, and suspended from the end of the bar is a tare weight 23 for balancing the weight of the casing 2 and its contained parts. Slidably mounted on the graduated arm 22 is a counterpoise 24; and depending y vertically from the fulcrum shaft I8 is a penduelbow 28 and then upwardly as at 29 to a fan casing 30 of a pressure fan 3I. Interposed in the horizontal portion of the air duct, and preferably` adjacent the casing 2, isla flexible section 32 which permits vertical movement of the casing yand itsxcontained parts.v The shaft 33 of the fan isf connected, as by a belt 34, with a motor 35. The ian casing 30 is preferably Yarranged adjacent the top of the main housing I, and an fection, irrespective air inlet duct 36 connects the same with the dust ber. To properly agitate the material resting on the perforated bottom, these jets of air should be in intermittent puffs; and to this end, suitable means are provided for interrupting the passage of air through the air duct to a sufiicient degree to produce this pulsating effect. The interrupter comprises a half cup shaped valve 31 mounted to rotate within theelbow 23 of the air duct. This valve is driven from the fan shaft 33 by suitable belting 38.

In operating the device, pulverized ore or mineral is fed in a continuous stream to the separator chamber where it rests upon the perforated bottom II and is subjected to the jets or puffs of air above mentioned. Such action of the air agitates the pulverized material and stratiiies the same, causing the lighter particles to rise to the top and permitting the heavier particles to settle to the bottom.- Some of the smaller particles of greater specific gravity will pass Athrough the perforations in the bottom II onto the hopper bottom 9 of the air chamber of the separator cup. To prevent accumulations in the air chamber, these portions which fall onto the bottom 9 move down the same to the conduit I0 and thence to the discharge orifice I6. The coarser portions of the heavier material will pass to the center of the perforated bottom II and be discharged through the conduit I4 into the lower portion of the discharge conduit I0. These, with that which has fallen through the perforated bottom I I, are the richer portion of the ore which are to be extracted. The lighter portions of the material accumulate as an upper layer or stratum, and when it accumulates to a suillcient depth it is discharged over the upper edge of the separator chamber 8 and falls through the space 2' between the same and the walls of the casing 2, to the bottom 3, whence lit passes out of the device through the chutes 5 and 6. To facilitate the discharge of the overiiowing lighter material from the separator chamber, an annular -deiiecting plate 39 is mounted in spaced relation above the edge of the cup 8 and is held in position by supporting rods 40 preferably attached to the walls of the casing. With each' air impulse the material in separator is thrown upward and such as rises high enough to strike the deflector plate is moved outwardly or away from 'the center of vessel towards the overflow.

To prevent any of the lighter material from entering the discharge conduit I4, a spreader element is supported within the Aseparator chamber directly above the discharge orifice 4I to the conduit,'so that, as the pulverized ore is fed into the chamber it is deflected toward the sides thereof and away from said orifice. As there is during operation, an accumulation of the heavier material as a lower stratum on the perforated bottom, this defiector comprises a double cone shaped member 42 'supported in any suitable manner as by supporting rods 43. l

One of the primary objects of the invention is to provide a lseparatorl that will continue to operate at a uniform degree of `percentage of perof variations inthe specific y tor chamber ythe same, irrespective of gravity or richness of the pulverized ore fed thereto. To this end,v I provide an improved feed mechanism and improved means for regulating the discharge of the heavier particles as they accumulate. An initial feed hopper 44 extends 5 through the top of the housing I and has a discharge orifice 45 at its lower end. Said lower end of the initial feed hopper extends within the upper end of an inverted frusto-conical feed chamber 46 having steeply sloping sides 41 and 10 terminating at its lower end in an orifice 43, Below the feed chamber and above the separator chamber is a -compensating chamber 49. This is an inverted frusto-conical member i'redly supported as by rods 5U to movewith said casing and the separator chamber. The compensating chamber receives the material from the feed chamber 46, and its lower end is open forminga discharge orifice 5I through which it discharges the material into the separa- 20 and upon the -spreader or deector 42. The feed' chamber 46 is stationary, and its lower ends extend a considerable distancewithin l the compensating chamber so as to remain within the movements 4of the 25 compensating and separating chambers. The orifice 5I is smaller than the orifice 41, and this in turn is' smaller than the feed hopper orifice 4l, so that, when the material is beingfed through the hopper 44 the material is maintained in the 30 feed chamber 46 at substantially the level of the orifice 45,; and the materialin the compensating chamber is maintained atl a level with the ori -flce 48.

Due to the steeply sloping side 41 of the feed 35 chamber 46, the pulverized ore is delivered to the compensating chamber 49 at a uniform consistency,A that is. at a uniform degree of compactness. Without'any material in the separator, the separating mechanism is exactly balanced by 40 the tare weight 23, so that when the material is delivered to the compensating chamber, the weight of said material therein tends to move said mechanism downwardly; and it is obvious that the degree of such movement is dependent 45 upon the specific gravity of the material'in said chamber. With this downward movement, the capacity of the compensating chamber is increaseddue to the relative greater distance between the orifices 48 and 5I. This downward 50 movement is therefore not directly proportional to the specific gravity of the material in the compensating chamber, but is proportional to the specific gravity and the variations in the-volume of the material. It is in order to maintain the 5'5 device in a fixed positionl of balance after it has reached a position due to the change of weight in the compensating chamber, that I provide the pendulum 25-26; and the pendulum weight can be adjusted on the pendulum arm to secure the 60 desired balance between the same and the material in the chamber 49. It is obvious, that any variation in the specific gravity of the ore being delivered will cause a corresponding shifting in the position of the"` separator, for a purpose which will appear hereinafter. Should the delivered material be of a greater specific gravity than thatA expected, the weight of the material' in the compensating chamber will increase and 70 tend to move the device downwardly proportional to the vincreased weight. Likewise a decrease in the specific gravity will decrease the weight in the chamber and permit the separatingA devicev to rise according tothe corresponding decrease 75 the casing 2, so asto l5,

in the volume of heavier material in said chamber.

*Means are provided, in combination with the compensating chamber and pendulum, for' recording the specific gravity of the material being delivered. To this end, an indicator arm 52 is fixed to the fulcrum shaft 8 and carries a stylus 53 for cooperation with the drum 54 which is driven in any suitable manner, as by clock work (not shown). This drum carries suitable indicia indicating 100% lof heavy material in the ore, and zero indicating no heavy material. It may be'graduated in between these limits to indicate any degree of perfection. It is obvious, therefore; that the grade or quality of the ore being fed to the device and the variations in its quality may be determined by reference to lthis indicating mechanism.

As the material is constantly fed to the separator at a substantially uniform rate, it is obvious that the combined discharge of both the heavier and lighter materials must equal the input; but the percentage of lighter and heavier material discharged from the machine will vary proportionately to the percentage of these materials in the ore. Theoretically, the material in theseparator chamber is stratified into a lighter upper stratum and a lower heavier stratum, but between these perfectly separated strata is van intermediate portion composed of both heavier and'lighter materials. Means are provided whereby the ore may be split, at any specific gravity. This will depend upon. the permitted rate of output or discharge of the accumulated heavier material. To this end, the discharge orifice I6 of the discharge conduitI Ill isy valve controlled so that there is no discharge of the heavy material when the device is at itsupper limit of movement, and a complete and unchecked discharge therefrom when the device is in its lowermost position. In order to maintain a constant discharge when the heavier or richer portion is 100% of the input, and prevent over-accumulation, said discharge orifice I6 is of a. capacity exceeding the capacity of the device, that is, exceeding the maximum inflow at the oritlce 5I. 'Ihe valve for the orifice I6 comprises a plate 55 mounted in the upper end of thev chute I1. and against which the lower end of the conduit I0 is firmly seated when the separator is at its upper limit of movement so as lto completely close the orificel I6. As soon as any downward movement of the separator is initiated, the aperturedvend of the conduit is moved away from the valve plate to relieve friction, and further downward motion'will Y,move the same to uncover the aperture I8 according to the degree of movement. In order to unseat the endof the chute upon initial downward movement, a lever 56 is provided, parallel with the supporting beam, and having its fixed end pivoted directly under the fulcrum shaft I8 of the beam, and its free end pivotally connected as at 58 to the conduit l0 on anaxis directly below the connectionl between the yoke 20 and the lugs 2|. This arrangement not only relieves the friction between the conduit and the valve 55 but maintains the device in true vertical position. The ,supporting-beam and the lever 55 are preferably horizontal when the device is .atits upper limit of movement so that the initial downward movement will retract the end of the'conduit from the valve plate 55.

.As the movement of the separator asing is primarily for the purpose of regulating the discharge'of the heavier material from thevoriflce y provided on the graduated bar 22.

above the bottom .of the valve plate so as to allow 5 some accumulation, and consequent slight downward movement, before a position is reached tov begin the discharge. To this end, stops 59 and 80 are provided on the casing 2 and a xed stop '6| is arranged,.as on the housing l, to cooperate therewith; the distance between the stops being such as to permit the desired maximum movement of the separator chamber and discharge conduit.

By decreasing the discharge rate of the heavier material, the 'ore will be split at a higher specific gravity, whereas by increasing the rate of dis- Acharge of the heavier material, it will be split at a lower specific gravity. In order that'the ore may be split as desired according to the desired 20 perfection of the output, the counterpoise 24 is By moving the counterpoise toward the fulcrum shaft, the weight of material will lower the separator, permit more rapid discharge of the heavier portions 25 and split the'ore at a lower specific gravity. By moving the counterpoise away from the fulcrum shaft the rate of discharge will be lessened and the ore split at a higher specific gravity. It is obvious that when splitting at a higher specic gravity, more of the heavier material will accumulate in the separating chamber than when splitting at a lower specific gravity.

As the input feed is no greater than the capacityof the device the combined output of light and heavy material must` equal the input. Consequently, the volume of material in the separating chamber is controlled by the ratio of lighter to heavier material. The greater the accumulation of heavier material in the device, the less lighter material`is required to maintain the mechanism in equilibrium; whereas with a decrease in the quantity of heavier material, there must be a corresponding increase in the quantity of lighter material; therefore, with a less degree of discharge of the heavy materials there is a correspondingly greater discharge oi' the light material.

The air valve 31 `creates intermittent agitations of material in separator cup 8, causing the material to rise and fall with eachY air impulse. The rising material at the top of each rise, strikes the deflector plate 39 and is deflected outwardly from the center of cup causing the material to pile'up and overflow the edge of the cup so that 55 it falls in space 2, to bottom 3 whence it passes outof the device through chutes 5 and 6. It is obviousthat the amount of material discharged over the top discharge of cup 8 will be in relation to the amount of material striking the deflector 60- /plate 39. When the cup is full, the discharge at itsntop will/be maximum; with a thinner total bed, the discharge will decrease until 'the bed becomes so thin that no material is'raised high enough to strike the deflector plate or overflow the top of cup 8. y

When the operation is for very light-materlal there is but a small bed of heavy material in the chamber and a large bed of light material; and the cup is full. This is` thenormal weight to be kept constant, and the output of light material is' substantially equalfto the iniiow. With more dense material, there is a thinner-total bed as there is an increase in the amount of heavier ma-f terial, obviously requiring .a less amount of the rial.

. material.

light material to produce a balance. With substantially all heavy material, there is a thin total bed and a thicker bed of heavier material. The line of separation :c between the heavy and light layers thus rises and falls to maintain the same weight with either increased or decreased volumes. 'Ihis is illustrated in Figs. 3, 4 .and 5 of the drawings. However, as there is a constant volume of feed, any variation in the specic gravity of the ore will vary the weight of the material in the separator cup whichl causes the separatorl to risev or fall accordingly, thereby varying the ratio of the heavier and lighter material until the device reaches the point of eq ilibrium for the material being operated upon.r

Thus, when the device has been set through the medium of the pendulum weight 26 and counterpoise 24 to operate upon material of a known or expected specic gravity and to split the same at the desired degree of richness, such degree of richness, or perfection will be maintained irrespective of fluctuations in the specific gravity of the ore fed to the device. Should the level of the heavier materials tend to rise into the upper 'field of agitation, the accumulated excess weight would lower the separating chamber, open the valved orifice I6 and permit discharge of the material to thus return the device to vnormal position and its equilibrium, and a constant quality of the output. Should the amount of heavy material in the ore fed to the machine become less, the proportionate accumulation of the heavy material will be less and the separator will rise, lessening the output of the heavier portion, and causing a greater discharge of the lighter mate- Likewise, upon an increase in the specic gravity of the ore.' the weight of the accumulated heavy portion will increase and lower the sepa-,.

rator, thereby increasing the output of the heavier particles and lessening the output of the light' material. I

lThe accumulated heavy portions in the disy charge conduit I above the lower end. of the conduit I4, acts as a valve to control the air pressure so that when the ore is running at substantial perfection, the device will move to its lowest position giving an unrestricted ow of the heavier The lower end of the conduit I4 will be free from the clogging action of the material in the conduit I0 and permit air to enter therethrough, relieving the pressure in the air chamber and consequently lessening the agitation in the separator chamber.

When extra light material is operated upon, it may be desirable to provide an air controlling damper in the airduct 21 so as to avoid iexcessive agitation. 62 indicates such a damper, which is connected to a movable portion of the device to open and close automatically with the fall and rise of the separator. This may be conveniently connected to thevtare weight as indicated at 63. With anexcess accumulation of lighter material in the separator chamber, the separator will rise` and as it rises, the damper is closed proportionately to the rise, so that the agitation of the material is decreased so as to avoid carrying over into the waste some ofthe valuable portions of automatically upon the feeding or cessatibn of the feed of the ore, the initial feed hopper 44 is mounted upon a 'tilting bar 64, fulcrumed at 65 and having a counterweight 66, which is of greater 'weight than the hopper 44 when empty, but of less Weight than the combined weight of the hopper 5 and contained ore. The end of the bar 64 opposite the hopper is provided with a contact member B1 which is adapted, when ore is in the hopper 44,

to engage the contact 68, closing the circuit 69 to the motor. As long as material isbeing fed to the hopper 44, the circuit to 'the motor is closed through the contacts 44 and 45. As soon as the materials cease to ow through the hopper 44, the counterweight 66 raises the hopper and breaks the circuit to the motor, thereby stopping the operation of the device.

I claim:

' 1. A device for separating the heavier from the lighter portions of pulverized material, comprising a separator chamber having a pervious bottom and means for forcing air currents through the bottom of said chamber, in combination with means for feeding pulverized material to said chamber at a fixed volume rate, means for discharging the heavier portions of the material from said chamber, means acting on saidI discharging means to maintain a substantially constant Weight of material in said chamber, and means i governed by the specific gravity of the material being fed and controlling said discharging means to cause the discharge of the heavier portions ofthe material from the separator chamber according to variations 'in ythe specic gravity of the material as it is fed to the separator chamber.

2.; In a separator of the class described, a sepag5 rator chamber having a-pervious bottom, means for forcing air currents through the bottom of said chamber, and means for feeding the material to said chamber at a uniform volume rate, in

combination with means for discharging the heavier portions of the material from said chamber, means acting on said discharging means to maintain a substantially constant weight of material in said chamber, and means responsive to density changes in the material While being fed by the feeding means for ascertainirg the density of the material as it is fed to the separator chamber and acting on said discharging means to vary the rate of discharge of the heavier material from the separator chamber according to variations in the density of the material.

3. In a device of the class described, a separator chamber having a discharge for the heavier porftions of the material, balance means movably supporting said chamber and controlling said discharge, and agitating means, in combination with means for feeding material to said chamber at a constant volume rate, compensating means for determining the relative density ofthe' material as itis fed to the separator chamber and acting on w said balance means to control said discharge according to variations in density of the material,

,said compensating means including means for delivering the materialto the separator chamber at a uniform degree of compactness.

charge, and agitating means, in combination with 10 means for feeding the material tb 'the chamber at a constant volumerate, and compensating means supported by said balance means for determining the relative density of the material as lit is fed to the separator chamber. and acting to control said 15 porting said chamber and controlling said discharge, and agitating means, in combination with means for feeding material to the chamber at a constant volume rate, compensating means for determining the relative density of the material as it is fed to the separator chamber and acting on said balance means to control said discharge according to variations in density of the material, and means responsive to said compensating means for recording variations in density of the material as it is fed to the separator chamber.

6. In a separator of the class described, a separating chamber having balance means supporting it for'limited vertical movement due to the accumulated weight of material therein, a down- .wardly extending discharge conduit for the heavier material, a compensating chamber supported by said balance means above the separating chamber and movable vertically therewith, said chamber having steeply sloping sides and an aperture in its lower end, a feed chamber having steeply sloping sides and an apertured end extending into the compensating chamber and means for coimterbalancing the weight of material in the compensating chamber in the various vertical positions of the separating chamber.

7. A device of the class described comprising a separator cup' mounted for limited vertical movement due to the variations of weight in its contents, a discharge conduit at the bottom of said'cup, a perforated plate in said cup dividing the same into an upper separating chamber and a lower air chamber, a discharge conduity extending downwardly from the separating chamber into the upper portion of the first said discharge conduit and forming a passageway between said condits which communicates with said lower air chamber, means for supplying air under `pressure to the air chamber, means for feed-ing granular material to the separating chamber at a fixed volume rate, and a valve controlling the lower end of said flrst discharge conduit to regulate the discharge of material therefrom proportionate to the vertical position of said chamber and through which air from said air chamber may escape more or less freely according to the amount of material contained in the rst said discharge conduit.

8. In adevice of the class described, a separator casing, including a hopper bottom having a discharge opening, a separator cup arranged within said casing and spaced from the walls yber, a discharge conduit extending downwardly from the separating chamber into the first said conduit, the lower end of the first said conduit having a lateral discharge orifice, Ya. stationary valve plate constituting a control for said orifice, a balance beam supporting said casing and separating mechanism, atare weight for balancing the same, and a counterpoise on said beam for determining the normal vertical position of the separator chamber for separating the ore at a de- V sired degree of richness, substantially as described. Y t

9. A device as set forth in claim 8 further characterized by a compensating chamber arranged above said separating chamber and movable 5 therewith, said chamber comprising an inverted frusto-conical member open at the bottom, a statonary feed chamber having steeply inclined sides and an open lower end extending-into said compensating chamber, and a pendulum in fixed relation to said beam, substantially as described.

l0. A device as set forth in claim 8 further characterized by a compensating chamber arranged above said separating chamber and movable therewith, said chamber comprising an in- 15 verted frusto-conical member open at the bottom.- a stationary feed chamber having steeply inclined sides and an open lower end extending into said compensating chamber, and a pendulum in fixed relation to said beam, said pendu- 20 lum comprising a pendulum arm and a pendulum weight adjustable thereon, as and for the purpose specified.

11. In a device of the class ldescribed comprising a separator casing having a hopper bottom, 25 a separator cuparranged within the casing and spaced from the walls thereof, said cup having a hopper bottom and a vertically disposed discharge condu.t, a perforated plate dividing said cup into an upper separating chamber and 'a'lower air 30 chamber, said plate constituting a hopper shaped bottom for sa.d chamber, a discharge conduit from the same extending into the upper end of the first said discharge conduit, means for supplying a pulsating air current to said air cham- 35.

bottom and a discharge conduit extending down- 45 wardly therefrom, a hopper shaped perforated Aplate dividing said cup into an upper separating chamber and a lower air chamber, a conduit extending downwardly from said separating chamber into the upper end of said first said conduit, 50 the first said conduit having a lateral discharge open-'ng in its lower end, a fixed plate normally closing said opening and constituting a valve for the same, a balance beam supporting said separating mechanism, a tare vweight on said beam 55 balancing the same, and a lever parallel with said beam having one end pivoted beneath the fulcrum of the beam, and thev other end pivotally connected to the discharge conduit directly below the connection of the beam to the separa- 50 tor mechanism, as and for the purpose specified. 13. A device as set forth in claim 12 further characterized by a means for supplying a pulsating air current to the air chamber and comprising an a.r duct extending laterally from the air 65.

chamber, a fan and fan housing communicating with said air duct and an interrupter valverotatably mounted in said duct, substantially as described.

14. A device as set forth in claim l2 further 70 characterized by means for supplying air under pressure to said air chamber and comprising an air duct extending laterally from the air chamber, a fan and fan housing communicating with said duct and a flexible section in said duct" y a,o14,oi ladjacent, said casing to permitri'se and fall of the separating mechanism, substantially as described.

15. A device of the class described comprising an outer separator casing having a'limited vertical movement, a separator cup arranged within the same and movable therewith and spaced from the side walls thereof to form passages extending downwardly from the top of the separator cup to the exterior of the casing for the descent and discharge of separated portions of lighter material, a perforated plate dividing said cup into an upper separating chamber and a lower air chamber, discharge conduits extending downwardly from said chambers, and means for'controlling the discharge of the heavier portions of the material under the control of the vertical movements of the separator casing, a stationary dust hood above said separator casing, the upperY end of said casing being open and extending loosely into said hood,v spaces being provided between said casing and hood for the admission of air to the latter, and means for supplying an air current to said air chamber comprising a fan and fan housing, an inlet duct for said fan hous.

ing communicating with said dust hood, and a duct leading `from said fan casing to said air chamber, substantially as described.

16. A device as set forth in claim 15 in combination-wlth a motor for said fan and a pivotally mounted initial feed hopper, an electric circuit for said motor and a circuit closerin said circuit actuatedby tilting of the said initial feed hopper. Y 17. A device of the class described, comprising a separator housing having a hopper bottom, and a discharge chute; a separatorcup arranged w'ithin said casing and having a hopper bottom, a discharge conduit extending downwardly from said bottom, the lower end of said discharge chute having a lateral discharge orifice,- 5 a fixed valve for'normally closing saidl orice, a hopper'shaped gerforated plate dividing said cup into an upper separating chamber and a lower alr chamber, a dischargev conduit extending downwardly .from said perforated plate"'into 10 the upper end of the first said conduit,- a balance beam supporting said separating mechanism, means for supplying pulsating currents of air to said air chamber, in combination with feeding means for said separating chamber com- 15 lprising a compensating chamber xedly supported above the same and comprising a frustoconical member having an open lower end constituting a discharge orifice, a stationary feed housing having steeply sloping sides and ter- 20 er than the discharge orifice of the initial feed hopper, substantially as described. y

` 18. A device as set forth in claim 17 further 30 characterized by a weighted pendulum flxedly connected to said balance beam, as and for the purpose specified.

JOSEPH W. REED. 35

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