US1573498A - Centrifugal separator - Google Patents

Description

Patented F el). 16, 1925.

PATENT' OFFICE.`

JOHN IVI.' NICOL, OF MILL VALLEY, CALIFORNIA.

CENTRIFUGAL SEPARATOR.

Application filed August 28, 1923. Serial No. 659,727.

To aZZ whom t may concern.'

Be it known that I, JOHN MALCOLM Nicci., a subject of the King of Great Britain, a resident of Mill Valley, in the county of Marin and State of California, have invented a certain new and useful Centrifugal Separator, of which the following is a specification. i

rllhis invention relates to a centrifugal machine, and more particularly to a centrifugal machine for use in metallurgical operations for the separation of fine gold and platinum and other heavy minerals from associated fine sands, and for like purposes.

This invention has as an object a centrifugal apparatus designed to separate two or more minerals or other-materials from each v other to provide separate products. Another A CFI object of the invention is to provide a form of apparatus that will be capable of concentrating out valuable metals such as gold and platinum from worthless associated sands or other metalliferous materials. A further object is to provide an apparatus for the treatf ment of sulphide minerals and the clean-up of dredging operations. Still another object 0f the invention is to provide an apparatus which will separate and concentrate niaterials by centrifugal action in such a manner that each particle is given a diiferential rotation during the course of the treatment so thata clean separation will be obtained. A still further object is to provide such an apparatus that will have means for regulating the amount of discharged concentrate while the machine is ruiming, so that the hnest adjustments may be made, and also to provide means for separating two or more concentrates, Further objects of the invention will appear as the following description proceeds.

Vilhile the apparatus described is intended for use in connection with metallurgical operations, it is to be understood that its structure is notl peculiarly limited thereto, but may be used for centrifugal operations in the chemical industryT and elsewhere where a Vmachine of its structure is of value. Thilo the invention may be represented in various embodiments, it is desired in the following preferred embodiment to describe a particu.

lar form of appa 'atus that is peculiarly adapted to certain metallurgical operations.

Accordingly the invention in its preferred embodiment is illustrated on the accompanying` sheet of drawings, in which,-

Fig. l represents a vertical central section of the centrifugal separator, and

Fig. 2 represents a modification of a part of the structure comprising the inner bowl.

In the aforesaid preferred embodiment, there is shown a main supporting frame l that carries an upper cross member 2 and a lower cross member 3. The upper cross member carries a removable angle bracket l serving as the supporting means for an upper bearing, and the lower cross member carries another removable angle bucket 5 serving to support a lower bearing, these bearings serving to support the revolving parts to be described later. 'lhere is also provided'a footstep block 6 having an oil well 7 and an adjustable center pivot 8, and a preferably brass bushed central vertical bearing 9.

The main revolving member in which the centrifugal effect is produced consists of a bowl l0 into the bottom of which is screwed a footstep shaft l1 held by a set screw The shaft ll revolves freely in the bearing 9 and rests on the pivot of the screw S, this mechanism being finely balanced so that the bowl will not revolve irregularly during operation. rl`he said bowl is provided with two interior annular riiiles lil and ll and a large annular concave rilile l5 designed to contain mercury in this particular embodiment. There is also a discharge orifice 1G provided with a removable plug.

A central vertical feed pipe 1T is screwed into the bottom of' the bowl l0 at a socket 1 8, and is provided with three openings near the said socket, one of which, lf), is shown. Said pipe 1T also serves as the driving niemberrfor vthe bowl l0, and for this purpose' is provided with a driving pulley 2t). flhc upper end of the pipe 'l revolves in a bearing 2l which is fitted into and held in place by a non-rotating vertical pipe The latter fits into a center hole in the bracket 4.-, and is supported by a removable threaded collar Q3.

The lower end of the pipe is threaded into a socket in a stationary massive ring' 24, which is maintained in concentric relationship with the central revolving pipe 17 of the bowl 10 by means of a center bushing 25 serving as an inner bearing. 0n the outside of theiixedpipe is located a simple clamp collar 26, held with set screws, and a flat disc 27 is'locatedtlrereon and connected to the massive ring` 24 by a short cylindrical section of pipe 28.Y The three n'iembers 24,-, 2T, and 28 are joined to-y gether and supported by the pipe as will be evident, thus forming,` a single non-rotatiupmember, which may be termed an inner guide bowl. As will be seen, this is stationary in the embodiment now being doscribed. i v

Above the disc n? is provided 'a ball bearing 29 on which runs an upper rotating hood bowlSO, which is suitably connected to and driven by a horizontal pull-ey 3l providedwith abearing 32'. Saidhood bowl 30 has an inner annular"concavegroove that is provided with a number of disons` openings such as 34.

it 'will be seen that the space between the lower bowl 10 and the upper hood bowl 30 represented by .numeral 35 constitutes an annular discharge orifice for the concentrates of higher density congegatingl against theiinside of the bowl 10, and this space 35 may be decreased or increased by manipulation of the .screw 8 so that an opening as line as 1/100 may bey obtained. A noteworthy feature of this structure is that such a line adjustment may be made during the operation of the apparatus, therebyv making,` it possible to obtain a clean separation during the running of the machine by observation of the nature and quality of the concentrate issuingthrough said opening- 35.

The dischar C'e of concentrates comin f j 7. s e t urough tne annular openm 35 will fall into a suitably placed launder shown atr36. The concentrates lying,` inside of the outer ring of heavier concentrates may be made to pass out through the openings 3d and will be discharged into an outer launder shown at 37.

A wooden plug 38 may be inserted in the bottom of the pipe 1T to close the same below the orifices 19.

ln Fig. 2 a modification is illustrated, showing a construction in which the inner` bowl may be made rotatable. A cross member 2 carrying a bracket 4, supports bearing 21 around a centrally fitted pipe 17. A central pipe 22 is mounted over the said bearing 21L and has screwed at the upper end thereof a driving member 39 rotating` from ball bearing 40. A bearing` l1 inserted in the bracket 4 serves to guide pipe 22. The latter is therefore made rotatable and consequently the corresponding massive ring and inner bowl, described in detail in the above embodiment, will be made rotatable, all other parts of the structure being the same as in the above described preferred embodiment.

In the operation of the machine, a suitable rate of .rotation is `given thereto and a charge of mercury is introduced into the feed pipe 17'and passes into the bowl 10 through apertures y19. lThe centrifugal action causes .the mercury to ascend the sides of tl e bowl and fill the 13, 1/1'-, and 15, any excess of mercury passing out through the opening ',lhe machine is driven atits cfitical speed so that a vertical wallV of mercury will be ietA -ned along the inside walls ol the bowl l() `without causing' any considerable quantity of this mercury to flow out through the opening' the purpose being to retain a watof menV in the bowl so that heavy metals .liie .Gold and platinum ill be re-v .ed therein :in their metallic staes,"and

:is over thev mercury and will rnalre their e'fit through the openings and 3a respecl tively. r fter the wall of mereurj.'7 has been formed, water is turned in at 17 and subseeuentiy ore pulp or sands are introduced and passed down the pipe 17 and into the bowl'lO. aqueous mixture to ascend the annular space between the bowl l@ and the inner bowl During this-time the materials are separated according' to their speciiic gravitiee. and are arranged in concentric annular layers or columns.` Consequently, by properly adjusting 'the width of the opening` 35, the outer heavier layer of concentrate may be removed while the inner layer passes on up and may be removed through the openings 34. ln the present machine only two such means ol removing concentrates are shown, but it will be understood that more than two openings may be provided for line concentrates. y

ln the embodiment illustrated, tlir'ee separations are effected- (l) heavy metals such as g'olu and platinum in'ibed themselves in the mercrry with` in the rililes, and they will bevrecover d when the machine is stopped and the mercury is withdrawn through the opening` 16.

(2l the nent heaviest remaining' mineral particles will be discharged through the annularopening 35.

and the tailings or least heavy minerals will be obtained through the opening` 341-.

'ille adustability of the opening' 35 dpermits a very line cut-out to be obtained so that the outer layer of mineral concentratesl may be almost entirely taken oli' without iemoving the other materials positionsM iu.- teriorly thereof. U

iin especial feature of this invention consists in the inner bowl 28 whichl may be 'lhe centrifugal actionv causes the till either fixed or relatively rotatable as illustrated. It is not always possible during the centrifugal treatment of minerals and similar materials to get all of the heavier constituents on the outside ring of concentrates without having imbedded therein some of the lighter materials. The tendency is for the heavier particles to seek the outer circumference during centrifugal action and to pin downand hold lighter particles, so that the normal tendency of the latter to escape inwardly is prevented by the strong pressure exerted by the heavier particles outwardly. rIhe provision of the inner bowl Q8, however, causes a differential rotation Vof the particles lying between it and the inner wall of the bowl 10: in other words, the position of the particles is periodically changed by the friction of the bowl 2S, thereby releasing the lighter particles and allowing them to escape inwardlyY to their proper positions as determined by their gravities. It will Vbe seen that for Vthus purpose the bowl 2S may be fixed or rotatable, the desideratum being to secure the relative movement between said bowl 28' and said bowl l0.

It will furthermore be seen that there is provided a vertical column of mercury reif'olif'ing in the form of a true cylinder, and that this cylinder of mercury is sufficiently long to provide a course of travel for the mineral particles and water moving upwardly, thereby enabling the minerals to position themselves according to their lgravi- 'ties in concentric layers. Although the action of the centrifugal forces is very rapid, the mineral particlesmust nevertheless be given sufficient time in which to find their proper positions. In the structuie shown herein a sufficiently long course of travel provided to produce this result, and consequently a very pure mineral concentrate maybe taken off through the opening 85, the purity of this concentrate beine' enhanced by the presence of the inner bowl Q8.

The present form of machine is particularly advantageous in the treatment of fine sands, clean-ups from dredging operations, and concentrating sulphide minerals. For example, it will Succeed in separating fine slime, galena, and sphalerite concentrates from each other, an operation which is otherwise verydifiicult. The machine may be used profitably to separate fine gold and platinum in metallic form from fine minerals or from otherwise worthless sands.

It will therefore be evident that an ap paratus has been devised in such form and proportions that it will be capable of treating materials otherwise difficult of treatment, so as to recover valuable minerals therefrom in a very simple and effective manner. The presence of an upper bowl makes it possible to secure a very tine adjustment of the first discharge opening during running of the centrifuge; and the presence of the inner bowl makes it possible 'to secure a differential rotation of materials undergoing treatment so that each particle will, during' the course of the treatment, be given a free opportunity to escape into its proper zone according to its density.

As many apparently widely different embodiments of this invention may be made without departing' from the spirit thereof, it is to be understood that I do not intend to limit myself to the specific embodiment thereof except as indicated in the appended claims.

I claim:

i. In a centrifugal machine, the combinationA of a bowl mounted for rapid rotation and having inner vertical sides provided with a concavity to hold a column of mercury, iffles in said sides below said concavity to also receive said nicrcury and heavy metal particles, said bowl being mounted for rapid rotation; and stationary means contacting with the inner portion of the material undergoing treatment for effecting a diii'cren* tial movement within a mass subjected to centrifugal force in said bowl.

2. In a centrifugal machine, the combination of a bowl mounted for rapid rotation and having vertical sides provided with a shallow concavity to hold a column of mercury and free from abrupt obstruction above said mercury column, stationary means contacting with the inner portion of the material undergoing treatment to effect a differential movement therein; an upper bowl mounted for rapid rotation and means for rotating it independently of the lower bowl, said bowl being fixed against vertical motion; and a vertical adjustable pivot point upon which the first named howl rotates whereby the space of the cutout between the bowls may be adjusted to any desired size.

3. In a centrifugal machine, the eomhina tion of a. bowl mounted for rapid rotation and having inner vertical sides io hold permanently a vertical annular wall of mercury, ritlles in said sides below said annular wall to receive mercury and heavy metal particles, said bowl being mounted for rapid rotation, and stationary means contacting with the inner portion of the material undergoing treatment for effecting a differential movement within the mass subjected to centrifugal force in said bowl.

Il. In a centrifugal machine, the combination of a bowl having vertical inner sides and mounted for rapid rotation on a vertically adjustable pivot; an upper bowl mounted for rapid rotation but lined against vertical movement, said upper bowl having an aperture for the discharge of lighter concentrates.

In a centrifugal machine, the combination lof a bowl having Vertical inner sides and mounted for rapid rotation on at vertically adjustable pivot; an upper bowl mounted for rapid rotation but fixed against Avertical movement, said upper bowl having with the inneil portion of the material miden going treatment to effect a differential movement therein. 10 In testimony that I ciaini the foregoing,

I hve hereunto sei. my hand this 25th day of August, 1923.

JOHN M. NICOL.

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