US1050720A - Art of centrifugal separation. - Google Patents

Description

H. DE RAASLOFF & T. E. BROWN. ART OF CENTRIPIIGAL SEPARATION.

, 1910. RENEWED NOV. 5, 1912.

Patented Jan. 14, 1913.

APPLICATION FILED JUNE 30 ia-wow" UNITED STATES PATENT oEEio HARALD DE RA ASLOEF AND THOMAS E. BROWN, 0]? NEW-YORK, N. Y.

'ART OF CENTR'IFUGAL SEPARATION.

Application filed June 30, 1910, Serial No. 569,631. Renewed November 5, 1912.

and THOMAS E. BROWN, citizens of the United States, and residents of theborough of Manhattan, in the county of New York and State-of New York, haye invented certain new and useful Improvements in the Art of Centrifugal Separation, of which the following is a specification.

This invention relatesto improvements in the art of centrifugal separation ofmaterials of different specific ravities.

The invention is applicable to the separation of materials of different specific gravities in all cases wherein at least one of the cable to cases in WlllGlltllB other material is also a liquid.

The essential step of theprocess is the,

generating, either through the centrifugal force'or through other agencies, of a pressure in the mixture less than normal atmos.

pheric pressure. This low pressure is generated at a part of the vessel containing the mixture, which is nearer the axis of rotation of the mixture than is the point at which .the' heavier concentrates are discharged from said vessel; and said part is also nearer the said axis ofrotation than is the part of said vessel in which the materials. Therefore, when, in the description or the claims, we use the term point,

I let for heavier material from the separating chamber or the part of said chamber in which the heavier material concentrates. Moreover, for, brevity of description, we

frequently hereinafter designate the said reduced pressure in the mixture by the term i vacuum, meaning thereby not necessarily an absolute vacuum, butany pressure less than the contemporary normal atmospheric.

pressure outside of the apparatus in which the process is then being operated.

The process therefore, broadly speaking,

consists in revolving the mixture of the materials which are to be separated, and at least one of which must be a liquid, around an axis of rotation, whereby a centrifugal force is developed which impels the heavier Specification of Letters Patent.

heavier materials concentrate as they separate from the lighter Patented Jan. 14, 1913.

Serial No. 729,659.

material outwardly from the said axis, and separates, or at least tends to separate, it from the lighter material. Simultaneously with the generating of the centrifugal force, a. pressure less than the normal atmospheric pressure is developed in a part of the mixture which is nearer the axis of rotation than is the point of concentration of the heavier material. The consequence of developing this reduced pressure at this part is that the normal atmospheric pressure'acts upon -the lighter material. in a direction opposed to the direction of the centrifugal fOTC,tIld, thereby, to the degree due to the excess ;of the normal atmospheric pressure over said reduced pressure, prevents the lighter material from moving outward with the heavier material. To produce the most perfect separation the velocity of revolution of the mixture is'limited so that the centrifugal force generated thereby in the lighter material is less than, or at least can never exceed the force due to, normal atmospheric pressure; and thereby the lighter materials areperpetually restrained from flowing .out'

by the discharge outlet for the heavymaterials and reuniting with them after the separation has once occurred. Finally the process includes the application of separate forces, independent of the centrifugal force, to remove the lighter and the heavier materials by different-outlets The process can be carried out by many ditle-rent'apparatus, among which are, for example, the apparatus ject of our application for United States Letters Patent filedMarch 16, 1909, Serial Number 483,670, and now pending; and the process can also be carried out by various other apparatus. The process is therefore hereinafter described, and the apparatus which is the sub-' not limited to any particular pparat telements, and we consider one aspect of our -i'rivention to broadly consistin the process as hereinbefore defined, however the apparatus which applies it may be constructed or arranged.

For the purpose of rendering the application of said process clear, we hereinafter describe it in connection with that form of apparatus which we prefer to use in connection with it, and We claim various parts and combinations of parts of said apparatus in to the discharge pipe 30, causes it to circu- 65 adivisional application. late properly in said chamber 25, and for a eferring to the drawings which accomtime suflicient to effect the separation of the pany the specification, and, as hereinbefore heavier materials. Said i 30 is prefer- 5 stated, illustrated the preferred form of apably carried at an upwar' inclination to or paratus for applying the process, Figure 1 slightly outwardly beyond the line of at- 70 shows a vertical section and elevation, partly mospheric pressure, P-P, where said pipe broken away, of an apparatus in which the is trap ed, as shown at 32, and is o ened mixture is drawn n by suction from below. to atmosplieric pressure just within said at- 10 Fig. 2 is a broken horizontal section of one mospherlc line as at 33'. From said trap 32 of the separating chambers. a discharge pipe 31 leads down and dis- 75' eferring to said drawings, a,rotary pipe charges into the annular revolving recepor vessel 1 1s revolved at high speed b any tacle provided with a suitable dischargc. suitable means, as gears 2, 3 and pul ey 5, In order to produce a final clarification of 15 from any source of power. Said pipe 1 is the separated liquid, we prefer to place anpreferably supportedvertically in suitable nular filtering screens in said receptacle bearings 6, 7, which may be anti-friction 40, and to arrange said receptacle 40 to disball bearings. Said pipe 1 is closed at the charge into a lower stationary annular retop 8, and its lower open end dips into theceptacle 68. Said filtering screens 60 are 20 materials to be separated in the vessel 20, to preferably composed of perforated metal which vessel they are delivered in any suit rings a hacked by any suitable filterin maable manner as by pipe2l, controlled by terial b. The outer end of each said sepvalve 22. Said pipe 1 is connected by arating chamber is connected with suitable branches 24 with any desired number of sepmeans for removing the concentrated 25 arating chambers 25, preferably arranged heavier material as rapidly as the same is symmetrically around said pipe 1;, and a formed; and the preferred device isillusshort distance above its junction with said trated in Fig. 1, and consists of a revoluble branches, said pipe 1 is closed as seen at 10. and reciprocating worm 43 in a worm cas- Below said branches is a control valve 12, ing 42. Said worm 43 may be all of uni- 30 preferably of long conical shape, seating on form pitch; or it may be of a plurality of aseat in diaphragm 11. A valve stem 13, different pitches 'Fig. 1 showing said suitably guided through the guides 16, 16,- is worm in two parts, whereof the upper part pivotally connected by lever 18, fulcrumed may have the greater pitch. Said worm casat 17, to a float 19, which rises and falls ac-, ing 42 may be throughout of uniform diam- 35 cording to the level of the contents of said eter or it may be of gradually increasing receptacle 20; and the arrangement of the diameter toward its discharge end; and said parts is such that when the level of said con worm and casing are preferably arran ed at tents rises said valve-12 opens, and when the an inclination upwardly and inward y, so level of said contents falls said valve 12 that the discharge from the worm takes place 40 closes; and by reason of the gradually taperwithin the said atmospheric line PP, and

mg shape of said valve 12 the opening and sothat the effect of said worm 43 is to proclosing of sa'id valve is also gradual, and pel the concentrates in a direction opposed perfect control of the-delivery of the mato that of the centrifugal force. Said worm terial to the separating chambers 25, and of discharges into a annular receptacle 69. R0-

45 the vacuum, is attained. A check valve 14, tary -and reciprocating motion are imparted guided on stem 13 and opening upwardly to said worm 43 in any suitable manner. may also be employed if desired.- The inner As shown in the drawings, the worm shaft closed end of each of said separating cham- 44, is suitably guided through the revolving bers 25 is arranged at a short distance. outbracket 45, which is carried on the sleeve 50 side of the line of zeropressure z-2,and 46, and revolves with said pipe 1. Said each of said chambers is preferably relatively worm is driven by beveled gear 47 meshing ection and provided with with beveled gear 48 carried on loose sleeve a contracted .outer end forming a nozzle. 49, which sleeve is in turn driven with dif- Each of said chambers 25 is also preferably ferent-ial velocity, by the gears 50. 51. A

' 55 provided with a partition 28 extending part square part of said worm shaft 44 works of the length of said chamber 25. The said longitudinally through a square hole in said branch pipe 24 connects with the chamber gear 47, but turns with said gear. Said on one side of said partition 28, and the disworm 43 can thus reciprocate while being rccharge for the lighter separated materials volved by said gear 47. A cam 52 carried 60 30 connects with said chamber '28 on the by said gear 57, and properly formed, lifts other side of said partition, and with the a rocker 53 pivoted at one end on said 12 top of said chamber 25, 29 being a diffusing bracket 45, and having a fork at the other screen. Thus said partition 28 preyents the end which engages under the head 54 of mixture from flowing directly from the inlet said worm shaft 44. Thus, at proper intervals, said worm 4:3 is moved endwise in the direction for discharging the concentrates, and as the'said cam 52 continues its revolving, the centrifugal force forces said worm in the opposite direction, thrusting the end of the worm into the concentrates, which then travel more or less up the said worm 43, as the same revolves and are finally lifted up to the discharge outlet by the end-wise motion of said worm. Of course springs or other devices in additionto centrifugal force could also be employed to force said worm into the concentrates. The reciprocating of the worm, with or without the increasing pitch, and with or without the gradually increasing diameter of the worm or the worm casing toward the discharge end, enables the worm to properly discharge materials of any quality or consistency, and whether the concentrates are slimy, greasy, or granular and gritty. Said worm shaft may be provided with a rotary cutter 70, to cut or scrape off the ends of the mass of concentrates, as the same are forced upward by the worm. We prefer to connect the outer ends of said separating chambers with the worm casings 42 by short pipes 57,

H as indicated, in order to equalize the mixture in said chambers 25 and said worm cas1ngs 42, particularly when the plugsof concentrates are of impervious clayey materials.

The production of the -vacuum.It being understood that the machine is revolved at such velocity that the centrifugal force at the point of discharge of the lighter ingredients will just balance atmospheric pressure, then we prefer to generate the vacuum in a part of each separating chamber which is nearer to the axis of rotation of the machine than is the pointlof discharge from the said chamber of the heavier ingredients, in the following manner: Suppose the separating chambers and other parts of the machine to be full of the mixture, the machine being originally at rest and the valve 12 closed, said chambers having outlets permitting the dischargeiof concentrates at the rate they are formed. Now suppose the 'machine to be revolved at the determined ve locity, valve 12 being still closed. Then the concentrates would form under the influence of centrifugal force, and the plug of concentrates would discharge, and there would be developed in part of said chamber 28 and said branch 24 and pipe 1, a vacuum. Now suppose the valve 12 is opened a certain amount, mixture then enters through said valve 12 into said chal'nbers 25, and the several i'naterials discharge therefrom only a the rate at which mixture enters through said valve 12, and manifestly there will be a pressure lower than normal atmospheric pressure in the pa'rtof said chamber which is within the line where the heavier materials concentrate, and particularly there will be a pressure lower than atmospheric in the part of said chamber 25 which is nearer the axis of rotation than is the point of discharge of the heavier concentrates. Consequently the normal atmospheric pressure will develop aforce in the light liquid opposed to the centrifugal force, and which prevents the lighter liquid from fiowing out with the heavier concentrate through the same opening. Thus the development of a vacuum in a part of the separating chamber nearer to the axis of rotation thereof than is the point of discharge of the heavier concentrates is an indispensable step in our process of separation, and while we prefer to generate the vacuum through the centrifugal force due to the revolution of the machine, yet we can develop said vacuum by means independent of the centrifugal force, as by suitable suction pumps properly connected with the inner ends of the separating chambers; and as hereinbefore stated our invention is not limited. to any particular means of producing said vacuum.

The process as a wholalhe process as an entirety is operated in the following manner; The apparatus having been suitably primed preferably when at rest, and the valve (or said valve 12 and check valve 14 if both are used) being closed, thema chine is started up. The centrifugal force causes the excess liquid to overflow at trap 32, and a vacuum is formed in pipes l and 24, and part of chamber 25. The supply valve 22 is opened the propenamount, the materials rise in receptacle 20, the float 19 opens the valve 12, and adjusts the area of the orifice to suit the supply admitted by said valve22, the atmosphere presses on the surface of the materials in said receptacle 20,' causes them to rise in pipe 1, and the centrifugal force projects the mixed materials into the chambers 25, where the centrifugal force causes the heavier matters to move outwardly and concentrate in the outer partand the nozzles of said chambers. At this point thc traps formed by the inward inclination of the worm casings 42 prevent the discharge of the said heavierconcentrates by centrifugal force. Therefore'said concentrates continue collecting at the outlets of said chambers and inlets of said worm casings, until the proper motion of said worm 43 pushes the end of said worm into the mass of concentrates, .and the rotation and the upward lengthwise motion of the worm-then discharge a mass of concentrates out of the upper end of said worm casing intosaid receptacle (39. Thus another step in our complete process is the removal of the heavier concentrates by a force or forces, other than centrifugal force. In the chamber 25, there is no tendency for violent even discharge of vsaid liquid from said 1 the reciprocating Worm the concentrates are slimy and slippery, with c'e'ntrateaand very soon after the machine V finally discharge mto 'chargedregularly and under control by its threads of the worm,

'is' started up there takes place a regular discharge of the concentrates into the said receptacle, '69;-the several motions of the orm :being so timed that the concentrates are removed at the rate at which they are formed. a

New having described our improvements we claim as our-invention.

mean time the lighter liquid material's flow gently, and without injurious eddies, around said partition 28 from the branch 24 to the pipe 30, to the traps 32, and thence down by pipe 31 to the filtering receptacle 40, being filtered through the filtering screen60, ahd receptacle 68. Thus, by reason of the vacuum in part of said gushing-out of the lighter liquid from the other materials of different specific graviseparating chambers, but there is a regular ties, and oneat least of which Is a liquid, which consists in revolving the mixed mate- 'rials and thereby generating centrifugal force in the mixture which throws the heavier material outward from the axis of rotation and tends. to separate it from the lighter material, and simultaneously developing a pressure lessthan atmospheric preschambers at the same rate as that at which the liquid is supplied to said chambers by said valve 12. In case an increased quan-' tity of mixture enters said receptacle 20, through some variation in the supply head, float 19 will rise and will open valve 12 until the discharge through said valve 12 sure in the mixture, whereby the greater into the separating chambers equals the normal atmospheric pressure opposes the cf amount delivered by valve 22 to receptacle fect of the centrifugal force on the lighter 20; and in case the quantity of mixture supmaterial and prevents said lighter material plied to said receptacle 20 by valve 22 de'- from moving outward along -with, said creases, float 19 will fall and valve 12 will heavier material; I more or less close-until the supply admitted 2. The process of separating from each to the separating chambers equals the quanother materials of difl'erent specific gravi' tity delivered to said receptacle 20. Thus ties, and one at least of 'which is a liquid, all irregularities in the supply are compenwhich consists in revolving the mixed matesated for, and the process continues without rials and thereby generating centrifugal interruption, the concentrates being reforce in .the mixture which throws the moved at the rate at which they are formed heavier material outward from the axis of and by their own proper outlet, and the rotation and tends to separate it from the lighter liquid being, asit were, held incheck lighter material, and simultaneously devely h excess f n rmal atm spheric presoping a pressure less than atmospheric pressure over that existing in the said part of v sure in the mixture, whereby the greater the separating chambers, and being d1snormal atmospheric pressure opposes the effect of the centrifugal force on the lighter material and prevents said lighter material from moving outward along with said heavier material, and extracting the concentrated heavy material as the same is con cent-rated.

proper outlet, separate from the outlet which the heavier concentrates are discharged,- and at the rate at which said liquidis delivered to said separating chambers.

he operation 0 the reciprocating charm-J11 connection with our said process 3. The process of separating from each hereinbefore deother materials of different specific graviscribed is very useful, although not i'ndis- .ties, one at least of said materials being a pensable. VVith-various materials of a gritty liquid, which consists in revolving the mixed nature the reciprocation, ofithe Worm may material and thereby generating centrifugal be dispensed with, since a rotary worm, force which throws the heavier material outwithout reciprocating, will properly convey ward from the axis of rotation and tends to and discharge such materials. But when separate it from the lighter material, simultaneously generating a pressure loss than atmospheric pressure in the sa d; mixture, wherebythe normal atmospheric pressure opposes the outward motionof the lighter material along with said heavier material, and applying force independent of the centrifugahforceto separately extract the concentrate'dheavier material and the lighter material.

4. The

but little friction against the walls of the worm casing, it is necessary to employ a reciprocating worm to efiect the proper discharge of the concentrates. For such concentrates are liable to merely revolve with the Worm in the casing and not to advance, unless the worm reciprocates. But. with our reciprocating worm, then, at properinter.- vals, the worm first pushes into the concentrates, which fill, more or less, a number of and then the upward motion of the worm lifts the charge of conm s of separating from each other materials of different speclfic gravr 1. The processof separating from each Lnof'soyao 'force which throws the heavier material outward from the axis of rotation and tends to separate it from the lighter material, siinultaneously generating a pressure less than atmospheric pressure in the said mixture, whereby the normal atmospheric. pressure opposes the outward motion of the lighter material along with said heavier material, applying force independent of the centrifugal force to separately extract the concentrated heavier material and the lighter ma terial, and clarifying the lighter material.

Signed at New York city in the county of New York and State of New York this 29th day of June A. D. 1910. M

HARALD DE RAASLOFF; THOMAS E. BROWN. Witnesses:

G. V. HOPKINS, WALTER N. HARRIS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Iatents,

' Washington, D. G.

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