US1767905A - Continuous centrifugal separator - Google Patents

Description

June 24, 1930. w. c. WALKER CONTINUOUS CENTRIFUGAL SEPARATOR 4 I Sheets-Sheet I l Z Iwntoz Filed Feby27, 1926 June 24; 1930. w. c. WALKER CONTINUOUS CENTRIFUGAL SEPARATOR 4 Sheets-Sheet 2 Filed Feb. 27 1926 June 24, 1930. w. c. WALKER CONTINUOUS CENTRIFUGAL SEPARATOR File Fe 2 1.926 4 Sheets$heet 3 attouwqs June 24, 1930. W. c. WALKER CONTINUOUS CENTRIFUGAL SEPARATOR 4 Sheets-Sheet 4 Filed Feb. 2'7, 1926 Patented June 24, 1930 UNITED STATES PATENT OFFICE WILLIAM c. WALKER, or NEW Yoim, N. Y.

CONTINUOUS GENTRIFUG AL SEPARATOB Application filed February 27, 1926. Serial No. 91,145.

This invention relates to means for eflecting the continuous separation of liquids from solids, and for the continuousdischargeis slow and tedious, and requires costly at tendance.

Attempts have also .been made to operate a centrifugal basket continuously by removing the solids therefrom while the basket is rotating, by means of various form of scrapers or unloading devices. This has been found impractical, however, on account of the necessity of moving the solids against the action of the tremendous centrifugalv force, and the impossibility, in any event, of running the scraper very close to the walls of the basket on account of the danger of damage to the latter.

It has also been heretofore proposed to substitute a foraminous flexible belt for the basket, and to lead such abelt over pulleys,

the material to be separated being fed onto the inside of the belt as it approaches one of the pulleys, and the liquids being thrown off as the belt passes around such pulley. Also it has been proposed to carry the belt around a discharge pulley in such manner that the curavature is reversed, and the solids thus'thrown 01f.

While there are many advantages inherent in the belt method of centrifugal separa- 4 tion, apparatus hitherto constructed to operate on this principle has not met with much commercial success, because of its inefficiency, structural defects, or for other reasons.

tinuous separators-of the belt t pe, and its general 0 ject is to so im rove t e construction and arrangement 0 apparatus of this character'as to render its operation highly efiicient and commercially desirable.

The present invention is directed to con-- Specifically, I contemplate greatly increasing the efliciency of the apparatus by subjecting the material on the belt to the action of centrifugal force a number of times before it is discharged. To this end, I propose to lead the belt a plurality of times around the same pulley or roller, the successive runs being maintained in spaced relation. I, have discovered that this can be accomplished by means of passing the belt over an auxiliary drum arranged with its axis inclined to and lying in a different plane from that of the main drum or roller,

so that as each run of belt is returned to the latter, it is displaced axially thereof. The amount of this displacement is determined-by the inclination of the axis of the auxiliary drum, and by other factors.

I further propose to subject the material on the belt to the action of centrifugal force of progressively increasing intensity as the belt travels from the charging to the discharging point; and to this end I lead the belt successively over a plurality of pairs of rollers or drums, one or both of the rollers of each pair being of smaller diameter than the preceding pair.

A further specific object of the invention is to provideimproved means for feeding material onto, or charging the belt. I have recognized the fact that if the materialis fed onto the belt in the same direction and at the same speed as that in which the belt is traveling, the work which would otherwise be requiredto accelerate the material is eliminated, and the load on the machine noticeably reduced, and I have embodied this principle in the construction of my apparatus. Y

A still further and subsidiary object is to provide means for effectively supplying wash water to the material on the belt at one or more points in its travel. This is often desirable, in order to free the solids more completely from any of the original liquids which may tend to adhere thereto. Moreover, I propose to independently collect the liquids which are separated previous and subsequent to the addition of wash Water, so that each may be appropriately" treated.

With the above and other objects in view,

the invention consists in the construction and arrangement of parts hereinafter described and claimed, and illustrated by way of example, in the accompanyin drawings, forming part of this speci cation, and in which Figure 1 is a plan View conventionally illustrating one embodiment of my invention;

Figure 2 is a side elevation thereof the front wall of the housing being removed;

Figure 3 is a transverse section substantially on the line 33 of Figure '1, looking in the direction of the arrow;

Figure 4 is a fragmentary side elevation showing the method of driving the rollers or drums;

Y plurality of runs'of a belt extending continuously around the same and passing from one to the other; and

Figure 10 is a conventional plan View similar to Figure 1, but illustrating a modified arrangement.

As stated in the preamble, one of the characteristic features. of the present invention consists in leading a belt a plurality of times continuously around a pair of drums or rollers, and in spacing the successive runs of the belt axially along the rollers. Sofa-r as I am aware, the accomplishing of this resultembodies a radically new mechanical principlewhich I have worked out, and in order to understand the theory of such an arrangement, reference will be had first to the geometric diagrams shown in Figures 8 I and 9.

As is 'well known, in all belt and pulley work, that portion-of the belt which is approaching the pulley must lie in the plane of the pulley. Otherwise, it will tend to progress axially and eventually run ofi'. Therefore, it is obvious that any attempt to operate a continuous belt passing a plurality of times around a pair of drums or rollers with parallel axes must fail. The runs of the belt would tend to crowd together and overlap in order to set themselves at right angles to the axes of the drums.

ment of the cable to be as indicated by the.

arrow, I have found that the various runs of cable will become stable and remain fixed in spaced relation when they have assumed the position shown in the drawin s.

It is obvious that in order for t ese cable runs to remain fixed, axially of the drums,

the fundamental condition above referred to must be satisfied, namely, each run must lie in a plane normal to the axisof the drum which it is approaching. That is to say, the tangent portion a b of the cable must lie in the plane defined by the arc portionv b c. In other words, the three points a, b and 0 must lie in one plane and this plane ,must be normal to the axis y. Similarly, the points 0 d a must all lie in a plane normal to the axis :0. Therefore, as viewed in Figure 9, the portions 0 (1 appear to form an angle with the portions b c. The reason for this is that the portions 6 c are necessarily in a plane normal to the axis while the portions 0 d are in a plane normal to the axis m. It will therefore be obvious that as thecable travels successively around the drums from the points a to the points I) and thence to the points a and d, the runs will be progressively shifted axially of the drums and will take up a position in which they are spaced apart, as shown, being in stable equilibrium in such position. The peculiar fact will be noted that the spacing of the runsat the right hand end of the drum B is greater than at the left handend, the spacing gradually diminishing from one end to the other. It is obvious that the amount of this spacing is proportional to the degree of inclination of the drum B.

In other words, the spacing can be' made anything'desired, within certain limits, by

varying the angle or inclination of the to provide a series of-relatively short in clined drums or rollers B, B, etc. and to pass a cable continuously around the drum A and successively around the drums B,

B. In Figure 9, I have illustrated a fragment of such a second drum B and it is obvious how the cable passes from it around the drum A andfthence to the drum B, with the runs maintained in spaced rela tion, as above described. I utilize this principl'e in the construction of my improved centrifugal separating apparatus. Referring now to Figure 1, I provide a housing or casing 1 of any suitable shape, enclosing a plurality of drums or rollers. As shown, I employ two main drums or rollers A, A, disposed horizontally in parallel spaced relation. Associatedwith the roller A are two auxiliary rollers or, drums B, B and associated with the roller A are two auxiliary inclined drums or rollers B B For a purpose hereinafter described, I provide the housing with partitions 2, 3 and 1, dividing the same into a plurality of independent compartments designated W, X, Y and Z. a r

The two main drums or rollers A and A are secured to shafts 5 and 6, supported in suitable bearin s and carrying driving pulleys 7 and 8. is shown in Figure 4, a driving belt 9 passes around the pulleys 7 and 8, and thence around a power pulley 10, mounted on a shaft 11 connected to; any suitable source of power, the belt also. passing under a guide pulley or idler 12. :Any

4 other convenient method of driving the drums A and A may, ofcourse, be employed; j

The drums B and B are loosely mounted on an inclined shaft 13, and the drums .B and B are loosely mounted on a similar inclined shaft 13', each of these shafts being offset at its middle portion, as shown at 1 1 in Figure 3, sothat one of the drums is dropped below the other, step fashion, as shown. It is more desirable to have a plurality of relatively short auxiliary inclined drums than to use a single relatively long one, on account of the fact" that with the plurality of drums,,it is possible to keep the different runs of belt or cable more nearly uniform in length.- It will be particularly noted that in the embodiment shown, the

.axes of all of the auxiliary drums or drum sections are out of'line with each other, but

that they all lie in the same plane, such plane being parallel with the plane of the axis of the main drum A. I propose to pass my improved filter belt around these various drums by employing the principles illustrated in Figures 8 and 9, all as will hereinafter more fully appear.

In order to supply to the traveling belt the material to be separated (hereinafter referred to as slurry), I employ a charging or feeding pulley, designated in its entirety by the numeral 15 in Figure 1. The actual construction of this pulley is clearly shown in Figures 5 and 6, and by reference to these figures, it will be seen that the pulley, in fact, comprises two similar halves or sections 15*" and 15", mounted to rotate loosely on alined hollow shafts 16 and 17.

The shaft 16 is supported in the side of the housing 1, while the shaft 17 is carried by any suitable fixed support 18 (see Figure 1). It will, of course, be understood that the halves 15 and 15 of the feed pulley are held against axial movement on their respective shafts by any suitable means. Each half 15 and 15 carries at the outer edge ofits periphery, a radial flange 15,

which serves to confine the belt.

At this point, it may be well to point out that my improved belt comprises a strip of flexible foraminous material 41, such as woven wire or the like, secured at each edge "to a relatively thick bead 12 of flexible, im-

pervious material, such as rubber or'suitably treated canvas. By reference to Figure 5, it will be seen that the bead 42 proects on each side of the strip 41, thus serving to hold such strip spaced from the center of both the chargm pulley and the wash water supplying device hereinafter described. The two halves of the charging pulley, shown in Figure 5, are spaced apart a distance substantially equal to the'width of the strip 41 between the beads 42.

At the inner ends of the hollow shafts 16 and 17 are circularplates or flanges 19, one of which is providedwith a rim 21, into which are set screws 20 or the like, for holding the two plates together to constitute a "central "disk-shaped body. This, it will be from the hollow shaft 16 and interior of the disk onto the belt. If necessary, and as shown in the drawmg, I may provide, within the hollow disk, a rotary pump or impeller comprising a wheel 23, carrying on one face radial ribs 24. This acts on the principle'of the well known centrifugal pump to draw the slurry in throu h the hollow shaft 16, and forcibly eject it t rough the port 22. The pump or impeller is secured to the end of a shaft 25, which carries at its other-end a pulley 26, driven by means of a belt 27 from apulley 28, secured to the shaft 5.

As mentioned in the preamble, it is very desirable to deliver the slurry to the traveling belt in the same direction and at substantially the same speed as that at which it is traveling. To this end, the tangential port 22 is positioned to deliver the slurry the mere hydrostatic head or natural flow of the slurry will be sufficient to give it the desired velocity at the portor nozzle 22, but

in other cases, I generate the necessary velocity by means of the impeller above described. Obviously, the speed of this impeller can be so adjusted as to deliver the slurry from the nozzle 22, at a velocity approximating that of the belt. In this way, the belt is relieved of the strain to which it would otherwise be subjected in continually accelerating the mass of slurry. With the arrangement described, the slurry passes smoothly onto the belt, without any excessive spattering and without any shock or impact. The slurry is, of course, received in the channel-shaped trough or groove formed by the heads at each side of the flexible strip constituting the bottom of the belt, and is laterally confined by the beads.

Below the main housing 1 is formed an auxiliary housing or chute 29, which encloses the discharge pulley 30, mounted on a shaft 31. The manner in which the belt 40 is led around this pulley will be hereinafter described.

The several compartments W, X, Y and Z are provided 'at their bottom with discharge pipes 32, 33, 34 and 35, for conveying away the liquid as it accumulates.

In order to supply wash water or other liquid to the belt at a point between the charging pulley and discharging pulley, I ma utilize, if desired, an arrangement such as lllustrated at the right of Figure 3, and also in Figure 1. This consists in dividing one ofthe auxiliary drums, such as B into two parts, in a manner generally similar to that shown in Figure 5, in connection with the pulley 15. One of the parts is shown as relatively narrow and is designated by the numeral 39. Between it and the main body of the drum B is interposed a fixed disk 36, having one or more radial ports extending the'rethrough from the center to the periphery, such ports communicating. at their inner end with a passage 37 formed in the fixed shaft 13'. It will be understood that the parts are soproportioned that as the belt passes over this water supplying device, one of the beads 42 engages the section 39, while the other bead rests upon the drum B thus causing the foraminous portion 41 of the belt to bridge the fixed disk 36. Therefore, water entering the passage 37 will be delivered outwardly through the radial ports 38 onto and against the material carried on the inside of the belt.

I propose to lead my improved belt continuously around each of the main and auxiliary drums a plurality of times, and also around the charging and discharging pulleys. Beginning at the bottom end of drum A in Figure 1, the belt passes horizontally over the adjacent drum B and thence around the charging pulley 15, where it is loaded with slurry, as above described. Any of the slurry which is in excess or which escapes for any reason, will collect in the compartment W and flow off-through the pipe 32. From the charging pulley, the

thence led continuously and alternately around the auxiliary drums B and B and the main drum A until the lower end of these drums is reached.

After the last run of the belt leaves the drum A, it is carried downward between this drum and the partition 4 through the bottom of the housing into the compartment or chute 29, where it passes under and around the discharge pulley 30, suitable guard rims 43 being provided around the openings where the belt goes through the bottom of the housing to prevent the escape of liquid therethrough. The belt coming up from the discharge pulley passes thence over the end of drum A and goes to the charging pulley 15, where the cycle is repeated. It will be understood that in Fig- 'and simplicity, only a single line to illustrate the path followed by the various runs of the belt, this line representing the center line of the belt. By means of this line, the course of the belt, as it travels throughout the apparatus, passing a plurality of times around each of the drums, may be clearly traced, and it will be observed that the same, law as to spacing obtains in Figure 1 as was discussed in connection with Figure 9. It will further be observed that the spacing is reversed as to drums A and A, this being'due to the fact that the runs of the belt pass from the drum A onto the auxiliary drums while they pass from the auxiliary drums onto the drum A.

It will also be seen, by reference to Fig-.

ures 1 and 2, that the drums A and B pass through the partition 3 dividing the compartments X and Y, and that the belt travels continuously from one of these compartments to the other. In this way, it ispossible to collect the liquors thrown off from the belt during the first few revolutions and treat them independently of the liquors thrown off during suceeding revolutions.

thereto. It will be understood, however,

that the wash' water supplying device may be located at any desired point, and that,

if necessary, two or more water supplying devices may be employed and located at different points.

In conclusion, it will be understood that the'material on the belt is subjected to centrifugal force repeatedly or a plurality of times, as the belt travels along, centrifugal force being, of course, generated each time that the belt; passes around any of the drums. It will also be seen that the material is subjected to centrifugal force a plurality of times both before and after being treated with the wash water.

It is, of course, obvious that as the belt passes around the discharge pulley 30, it is flexed .in the opposite direction to that in which it was flexed when passing around the separating rollers A, B etc. and as a result, the solid material which has accumulated thereon and which may have- Worked into the "interstices of the belt, is effectively dislodged and thrown off.

In certain prior apparatus which has been proposed, the slurry is fed to the belt as it approaches a pulley, thus causing charging and separating to take place substantially at the same point. l/Vith my arrangement, on the contrary, the charging'pulley is located in a different compartment from the separating drums, no separation taking place until the belt begins to travel around the drum A after leaving the charging pulley. Moreover, by reference to Figure 6, it will be particularly observed that the supply nozzle 22 is so located as to deliver the slurry onto the belt at substantially the point where the belt leaves the pulley.- Thus, the material is not subjected to centrifugal force at the charging pulley.

An important feature of the invention'resides in the fact that by a slight modification, it is possible to subject the material on the belt to centrifugal force of progressively increasing intensity, as the belt travels along. An arrangement for accomplishing this is conventionally illustrated in Figure 10. In this figure, it will be seen that instead of having the auxiliary drums all of the same size, as in Figure 1, I make them of progressively decreasing diameters. These auxiliary drums are designated in Figure 10 by the numerals B, B B and B", and it will be seen that B is the largest, while B, B and B are progressively smaller and smaller.

The result of this is, that, since all parts of the belt must necessarily travel at the same speed, the smaller the drum, the greater number of revolutions per minute it must make; in other words, the greater must be its angular velocity. Thus, it is evident that the centrifugal force at each drum will. vary inversely as its diameter, and that therefore, the centrifugal force is greater and greater as the belt travels around drums of successively decreasing diameter.

As indicated in Figure 10, it is necessary to arrange the drums B 13 and B with their axes at progressively: increasing angles to the axes of the drums A, in order to secure and maintain the spacing of the belt runs illustrated; that is to say, the same spacing as in Figure 1.

While in Figure 1 I have shown all of the rollers as of the same size, it is obvious that the auxiliary rollers can all be smaller or larger than the main rollers, if desired. Also, While I have shown each auxiliary drum as consisting of but two rollers or sections, such as B and B, it is obvious that each may be made up of any desired number of sections arranged .in stepped relation. Thus, if desired,a separate drum section or pulley maybe provided for each run of the belt.

. Furthermore, while iin the drawings I have shown each run of belt as passing over only two drums or rollers, it is obvious that each run may be made to pass over three or more rollers, if desired. This bvcomes particularly advantageous where therollers are very small.

Although I have found that my improved method of arranging the axes of the drums in angular relation results in maintaining the runs of the belt effectively spaced apart,

still in some cases, guide flanges on the rollers may be provided, if necessary, or the drums or rollers may be crowned in places.

While in the drawings I have shown the drums A, A as horizontal, it will, of course, be understood that I do not limit myself to this arrangement, but that these drums may be disposed at any angle desired.

What I claim is 1. In apparatus for separating liquids from solids, the combination with an endless foraminous belt, of means forfeeding onto said belt the material to be separated, and pulleys around which said belt continuously passes in such manner that the material is subjected to the action of centrifugalforce in the same direction a plurality of times while on the belt.

2. In apparatus for separating liquids from solids, the combination with an enclless foraminous belt, of means for causingthe belt to travel continuously, means for feeding onto the belt at one point the material to be'separated, means for removing the solids from the belt at another point, and means'bctween the feeding and removal points for subjecting the material on the belt to the action of centrifugal force a plurality of times in the same direction.

8. In apparatus for separating liquids from solids, the combination with an endless foraminous belt, of means for causing the belt to travel continuously, means for feeding onto the belt at one point the ma- -terial to be separated, means for removing the solids from the belt at another point, and means between the feeding and removal points for subjecting the material on the belt to the action of centrifugal force a plurality of times, the centrifugal force applied being of progressively increasing intensity.

4. In apparatus for separating liquids from solids, the combination with an endless foraminous belt, of means for causing,

the belt to travel continuously, means for feeding onto the belt at one point the material to be separated, means for removing the solids from the belt at another point, and means for subjecting the material on the belt to the action of centrifugal force which increases progressively in intensity from the feeding to the removal point.

5. In apparatus for separating liquids from solids, the combination with an endless foraminous belt, of means for causing the belt to travel continuously, means for feeding onto the belt at one point the mathe solids from the belt at another point,

means for supplying liquid to the belt at an intermediate point, means for sub ect- 'ing the material on the belt to the action of centrifugal force both before and after it reaches the liquid supply point, and means for independently collecting the liquid thrown off from the belt at each side of said point.

7. In apparatus for separating liquids from solids, the combination with an endless foraminous belt, of means for causing the belt to travel continuously, means for feeding onto the belt at one point the material to be separated, means for removing the solids from the belt at another point, means for subjecting the material on the belt to the action of centrifugal force a plurality of times in the same direction between the feeding and removal points, and means for independently collecting the liquid thrown off from the belt at different stages of its travel.

8. In apparatus for separatlng liqulds from solids, the combination with a pair of spaced drums, and means for rotating one of them, of a foraminous endless belt arranged to pass continuously over each of said drums a plurality of times, and means 9. In apparatus for separating liquidsfrom solids, the combination with a feed pulley, of a pair of spaced drums, means for rotating one of them, and a foraminous endless belt arranged to pass continuously over said feed pulley and drums, said belt running around said drums a plurality of tunes.

10. In apparatus for separating liquids from solids, the combination with a feed pulley, and a discharge pulley, of a pair of spaced drums and means for driving one of them and a foraminous endless belt arranged to pass continuously over said feed pulley, drums, and discharge pulley, said belt running around said drums a plurality of times before going to said discharge pulley.

11. In apparatus for separating liquids from solids, the combination with a feed pulley, discharge pulley, and liquid supply pulley, of a plurality of spaced drums and means for driving one of them, and a foraminous endless belt arranged to pass continuously over said pulleys and drums, said belt running from said feed pulley to and around some of said drums, thence over-said liquid supply pulley, and thence around others of said drums to said discharge pulley. I

12. In apparatus for separating liquids from solids, the combination with a feed pulley, of a pair of spaced drums, means for rotating one of them, and a foraminous endless belt arranged to pass continuously over said feed pulley and drums, a housing enclosing said drums and divided into compartments, said drums lying partly in different compartments, and said belt being led several times around the drums in one compartment, then passing to another comchamber as the belt passes around said drum.

14. In apparatus for separating liquids from solids, a feed pulley, a separating drum and means for driving it, and a foraminous endless belt arranged to pass continuously over said pulley and drum, whereby material. deposited on the belt by said feed pulley is subjected to centrifugal action as the belt passes around the separating drum.

1a. In apparatus for separating liquids i from solids, a feed pulley, a separating drum and means for driving it, a foraminous endless belt arranged to pass continuously over said pulley and drum, and means for feeding material to be separated tangentially onto said belt as it passes around said feed the velocity" of delivery being subpulley, stantially equal to the speed of the belt.-

16. In apparatus for separating liquids from solids, a feed pulley, a separating drum and means for driving it, a foraminous endless belt arranged to pass continuously over said pulley and drum, and means'for feeding material to be separated tangentially from the periphery of said pulley onto said 1 belt at a point just before the belt leaves said belt.

the pulley. 17. Means for feeding fluent material to a foraminous belt comprising a pulley over which said belt passes, said pulley having a central fixed hollow portion, and means for discharging the material tangentially from said fixed hollow portion onto the belt.

18. Means for feeding fluent material to a foraminous belt comprising a pulley over which said belt passes, said pulley having a central fixed hollow portion provided wlth a substantially tangential port, and meansfor drawing the material into said hollow' portion and forcing it out through said port onto said belt.

19. Means'for feeding a foraminous belt comprising a pulley over which said belt passes, said'pulleyhaving a central fixed hollow portion provided with a substantially tangential port, and a rotary pump element mountedwithin said hollow fixed portion and serving to draw in the material and eject it through said port onto 20. In combination, a filter belt, a smooth surface roller around which said belt passes, said belt comprising a porous flexible strip having at each edge a marginal flange or bead for engaging said roller, whereby the strip itself is spaced from the roller, and means for feeding the material to be filtered onto the inner side of said .belt so that it occupies the space between said strip and roller. 7

ture.

WILLIAM G. WALKER.

fiuent material to In testimony whereof I aflix my signav

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