US2723754A - Hydraulic sizer for suspended solids - Google Patents

Description

Nov. 15, 1955 G. M. DARBY HYDRAULIC SIZER FOR SUSPENDED SOLIDS 9 Sheets-Sheet 1 Filed July 23, 1952 r. w n 0. D I

George M. Darby orneg Nov. 15, 1955 G. M. DARBY HYDRAULIC SIZER FOR SUSPENDED SOLIDS 9 Sheets-Sheet 2 Filed July 23, 1952 ZSnventor George M. Derby 4): totneg Nov. 15, 1955 s. M. DARBY HYDRAULIC SIZER FOR SUSPENDED SOLIDS 9 Sheets-Sheet 3 Filed July 23, 1952 Snventor George M. Darby ttorfieg Nov. 15, 1955 G. M. DARBY 2,723,754

HYDRAULIC SIZER FOR SUSPENDED SOLIDS Filed July 25, 1952 9 Sheets-Sheet 4 5 Fig. 4.

38 33 38 A L 1 T if; I'mventor George M. Darby /0 i 4 J ax Nov. 15, 1955 G. M. DARBY 2,723,754

HYDRAULIC SIZER FOR SUSPENDED SOLIDS Filed July 23, 1952 9 Sheets-Sheet 5 Ii 25" s) Illlll lu 7 9 /29" INVENTOR George M. Darby ATTORNEY Nov. 15, 1955 Filed July 23, 1952 G. M. DARBY HYDRAULIC SIZER FOR SUSPENDED SOLIDS 9 Sheets-Sheet 6 3nventor George M. Darby attomcg 7 Nov. 15, 1955 Filed July 23, 1952 Fig. 7

G. M. DARBY HYDRAULIC SIZER FOR SUSPENDED SOLIDS 9 Sheets-Sheet 7 3nventor George M. Dorby uiw x (Ittomeg Nov. 15, 1955 s. M. DARBY 2,723,754

HYDRAULIC SIZER FOR SUSPENDED SOLIDS Filed July 25, 1952 9 Sheets-Sheet 9 Imnentor George M. Darby J e 2 1D 0 tomeg United States Patent 1 2,723,754 HYDRAULIC SIZER FOR SUSPENDED SOLIDS George M. Darby, Westport, Conn.', assignor to Dorr- Oliver Incorporated, a corporation of Delaware Application July 23, 1952, Serial No. 300,559 6 Claims. (Cl. 209-461) This invention relates to apparatus for hydraulically sizing or classifying a mixture of solids into a sequence of size fractions or group of sizes, the first to contain a range of the largest sizes, with the following groups or fractions each to contain a range of sizes smaller than those in the range of the preceding group or fraction.

More particularly, this relates to hydraulic sizers of the hindered settling type the general operating principle of which is represented in and by the well-known Fahrenwald sizer as shown for example in British Patent No. 268,663 with filing date of October 4, 1926.

In classifying or sizing apparatus that operates on the hindered settling principle the sizing or solids fractionation of a slurry containing the mixture into a desired fraction of coarse solids and a desired fraction of finer solids is eflected as the mixture of suspended solids feeds into and passes across a pool or pocket or vertical column of liquid from the bottom of which rises a cross-sectionally uniform stream of pressure water which is the so-called hydraulic operating water or simply hydraulic water. In order to attain a desired size fractionation, the quantity and upflow rate of this hydraulic water must be established in relation to certain other operating factors, namely the density of a teeter bed of suspended solids to be maintained constantly in the column, the rate of coarse solids discharge (spigot discharge) from the bottom of the teeter bed, and the rate of slurry feed to the column. That is to say, by the setting of the upflow rate of the hydraulic water and by maintaining the proper density of the teeter bed in the column through the constant control of the rate of the coarse solids discharge from the bottom spigot, this type of apparatus permits relatively sharply controllable classification of the slurry mixture into a coarse spigot fraction of a desired size range and an overflow fraction of fines of another desired range. In other words, the character of the fractions, namely of the coarse spigots discharge and of the fines overflow, from such a hindered settling column is determined and depends upon the accuracy of control of the density of the teeter bed against the upflow of the hydraulic water, devices for such control being well known and provided in the form of a liftable valve member seated in the spigot discharge opening in the bottom of the column, together with automatic devices for correctively positioning the valve member in such a manner as to compensate for any deviations from the desired state of density of the teeter bed by a corresponding increase or decrease of the coarse solids spigot discharge.

As embodied in the early Fahrenwald sizer or in any of its later and more recent improvements (such as patent to Haagensen, No. 2,371,615 of March 20, 1945; patent to Darby, No. 2,410,637 of November 5, 1946; and patent to McKay, No. 2,425,551 of August 12, 1947) the type of apparatus herein considered represents a multiplespigot, hindered settling classifier which, from a feed suspension mixed with respect to particle sizes, produces closely sized spigot products along with an overflow carrying fines.

Such a multiple spigot apparatus comprises a sequence or horizontal row of teeter bed columns with the slurry to be classified entering at one end, passing sequentially over these columns or pockets while leaving behind in each pocket the respective hydraulically controlled and selectively intercepted size fraction, with a final fines fraction escaping with the liquid overflowing at the other end. Thus the desired solids fractions are abstracted sequentially from the horizontal stream of slurry passing through the apparatus by way of the respective teeter columns or classifying pockets of this apparatus and these fractions are delivered as the respective spigot product therefrom.

This invention is an improvement upon and over the classical Fahrenwald form of multi-pocket hindered settling sizing apparatus, which form in principle has maintained itself up to date even though improved with respect to certain control accessories such automatic density control mechanism disclosed in some of the abovementioned patents.

This invention then can be said to provide an improvement over a structure which is known to comprise a longitudinal tank with vertical side walls diverging somewhat from end to end of the tank and having transverse submerged vertical partitions dividing the tank into a horizontal sequence of classifying or sizing pockets or columns trapezoidal in plan view, with the spacing between the partitions increasing towards the wider end of the tank whereby in plan view area the pockets increase towards the Wider end of the tank. The mixed solids suspension or feed slurry enters the narrow end of the tank continuously While liquid carrying the residual fines overflows a weir defining the liquid level above the partitions in the tank, even as the various size ranges of the solids received by respective pockets discharge continuously from respective spigots as sized products.

In such conventional apparatus the character of the size portions as delivered by respective spigots is controlled by hydraulic Water supplied to a hydraulic feed chamber provided directly underneath each respective teeter column and rising through a constricton plate or perforated member constituting the bottom boundary of the teeter column proper. In such apparatus there is provided the usual vertical and centrally disposed spigot discharge duct for each teeter column or pocket which duct extends through the hydraulic feed chamber presenting a central dischargeopening in the constriction plate and constituting therein a valve seat for a conventional conical valve member or plug. The valve member has a vertical stem extending upwardly into connection with an automatic control unit disposed at the top of the tank for each pocket and whereby the valve member is correctively raised or lowered with respect to its seat for correctively varying the spigot discharge rate individually of each teeter pocket. The operation of each density control unit is governed by variations in the density occurring in each respective teeter bed, inasmuch as the control unit responds to density variations by way of a clear water column that communicates with thebottom strata of the teeter bed. Thus any increase or decrease in density will produce a corresponding degree of rise or fall of the clear water column which rise or fall in turn acts upon the control unit to produce proportionate corrective control effects in terms of raising or lowering the valve member relative to its seat, so that a density close to a desired value is correctively maintainable in the teeter bed. Examples of density control devices thus governed by variations of a clear water column are shown in the above-mentioned patents to Haagensen, No. 2,371,615 and McKay, No. 2,425,551.

Such conventional multiple pocket classification units especially if equipped with automatic density control are ideally suited to meet certain requirements for accurate size control, for example in treatment of slurries where particle difference of micron accuracy may be important as in the sizing of abrasives. Yet, the present day apparatus of this type may be said to have reached a unit capacity limit in view of the fact that even with the use of automatic density control devices a uniform density becomes more difiicult to attain and to maintain with 3 any increase in area of the respective pockets served by the respective spigot discharge control devices.

Moreover, the conventional hydraulic multiple pocket sizing unit depends. for its proper operation. and for the attainment of the desired-sizing effects upon the provision for each pocket of the proper type of constriction plate, namely a plate having the number and size as well as spacing of the holes best suited to bring about the desired efi'ects. Hence, to inspect these constriction plates for wear or other reasons or to change such plates for operational reasons, has requ red not only the shutdown of the operation, but also the dismantling of the bottom sections or hydraulic chambers. as well as of the water supply connections for these chambers with attendant protraction of the shutdown.

As regards capacity and other operational characteristics these are notreadily predictable for the conventional apparatus especially for any projected increase of size andcapacity, hence design data for a projected capacity machine are not readily arrived at due to uncertainty or unpredictability of performance characteristics, where capacity changes especially increases over present day capacities are contemplated.

At any rate, the present day multiple pocket multiple spigot hydraulic sizing apparatus of the hindered settling type may be said to have reached the limits of its structural size inasmuch as further increase of apparatus size for the purpose of increasing the total capacity would tend to make the apparatus structurally relatively less economical while rendering it relatively less efficient or accurate or selective with respect to desired particle sizing results.

It is among the objects of this invention to provide a multiple pocket multiple spigot hydraulic sizer unit with the capacity to handle liquid volumes along with quantities of solids far beyond present day capacity limitations, yet without sacrificing controllability of density conditions in the respective hindered settling pockets and without sacrificing acccuracy of size fractionation. Indeed, it is among the objects to provide a supersize high capacity unit that is readily and uniformly controllable as to density condition in all its areas and possesses exceptionally well controllable particle size selectivity and high fractionation accuracy in the sense that each fraction or spigot discharge contains a minimum of tramp sizes or of sizes. contained in the spigot discharge of an adjoining pocket, and yet, which supersize unit is relatively cheaper to construct and will by comparison require much less shutdown time if any, and which will. avoid opera tional-, design-, and constructional-problems encountered with the use of the conventional constriction plates.

Indeed it is among the objects to provide distributing means whereby a uniform and uniformly controllable upfiow of hydraulic. water is provided in each pocket area without necessitating the use of constriction plates; such distributing means to be readily inspectable and exchangeable without requiring any of the cumbersome dismantling heretofore necessary, so that labor and the duration of the shutdown may be minimized.

These objects are attained by way of a new concept according to which the apparatus unit or multiple spigot tank is visualized in plan view as a combination of cooperatively associated columnar component volumes definable by a system or combination of submerged transverse and longitudinal vertical partitions which constitute the boundaries of transverse. rows. of columnar cells, of substantially identical square cross-section. Each such cell is to hold 'a teeter bed of individually controllable density, with the solids-carrying liquid passing above this system of partitions and teeter beds in a direction from the narrow end to the wide end of the tank. Moreover, each of these columnar cells or teeter beds is equipped with its own automatic density control devices, namely a spigot outlet valve with individual automatic control unit therefor.

Hydraulic water is controllably supplied to each transverse row of columnar cells or teeter beds not through conventional constriction plates, but is introduced from an overhead horizontal pipe system by way of a depending system of jet-emitting distributing pipes. That is to say, vertical branch pipes extend from the overhead pipe system downwardly into each columnar cell or teeter bed and they connect with horizontal jet-emitting pipes. The jet-emitting pipes for each cell are supported upon and spaced a predetermined distance from the solid nonperforated square tank bottom portion of the cell which has the valved spigot outlet in the center. Indeed, each such basic, square cell may thus be provided with a substantially identical system of horizontal jet-emitting parallel pipes, the pipes being so placed from one another and from the boundaries of the cell, and the jet-emitting orifices in these pipes being so arranged and dimensioned and so disposed with respect to one another that there results from such arrangement in each cell an upflow of hydraulic water from the bottom which upfiow is substantially uniform and uniformly controllable across the area of the teeter bed or cell, and adapted to sustain a teeter bed of desired density.

According to this invention then, the apparatus or tank presents itself as a combination or honey-comb-like system of basic square cell units or teeter beds of equal predetermined size, each with its individual spigot dischargev and automatic density control and with a substantially identical jet-emitting pipe system for hydraulic water supply, so that the apparatus may be said to represent the employment of a multitude of the basic cells each complete with control devices and overhead hydraulic water supply, in such a manner that a single such cell constitutes the narrow end of the tank while a plurality of such cells in a transverse row constitutes the wide end of the tank. Thus a plan view of the tank presents a characteristic configuration namely with sides which are stepped from the narrow end to the wide end of the tank. Indeed, the total area presents itself as a sequence of rectangular areas or transverse sizing zones of stepwise increased width, each of which zones comprise one or more transverse rows of the submerged square cells; each rectangular area or transverse zone is larger than the preceding one upstream, whereby there results the above-mentioned stepped configuration of the tank.

Such stepped configuration simplifies design as well as fabrication of the tank inasmuch as it confines all structural wall area components of the tank to simple rectangular shapes of readily determinable size. Moreover, importantly fora supersize tank made possible by this invention this stepped configuration presents the opportunity of conveniently subdividing the tank transversely or zone-wise into two or more assembly sections each of which maybe loaded and shipped individually for subsequent complete assembly at the destination, this being in contrast with the heretofore customary type of onepiece apparatus units of much smaller capacity.

Features of this invention lie in the hydraulic water supply and distributing system for the tank, insofar as it comprises a multitude of jet-emitting sub-systems each serving a respective cell or teeter bed. Water supply connections or pipes extend from the horizontal jetemitting pipes upwardly within the tank in. each cell to connect with horizontal water supply headers extending above the tank; characteristically, the. vertical connections or pipes are readily disconnectable from. their respective supply headers in such a manner as to enable each re" spective sub-system to be lifted out of the tank after disconnecting it from, its overhead, supply header, for inspection or exchange.

According to a more specific feature, since the tank according to. this invention consists of transverse rows of square cells or teeter beds, each such row is provided with. an overhead. water supply header transversely coextensive with ,therow. of cells, and, for each cell a pair of vertical supply connections or pipes extends symnietrically down from the header, namely. one vertical pipe from each respective side of the header.

Each such vertical supply connection or pipe in turn connects at the lower end with a pair of symmetrical branch connections constituting an inverted Y, each branch connection in turn terminating in and connecting with the middle of the length of ahorizontal jet-emitting distributing pipe which while closed at its ends has extending along its length rows of jet-emitting orifices or holes. Each such pair of horizontal jetemitting pipes while supported in spaced relationship relative to and by the bottom, is removable from its cell by having the upper end of its vertical supply pipe disconnected from the header, an adjustable connection being provided which is not only readily disconnectable but also capable of adjustably absorbing any changes in the vertical spacing of the horizontal distributing pipes from the bottom. Further particularized, any such change in the vertical spacing of the horizontal jet-emitting pipes is absorbable by a vertically adjustable or telescoping type of sleeve or flexible hose connection provided between the vertical pipe and the header.

According to a more specific feature, the transverse overhead water supply headers serve as mountings for the automatic density control devices so that there is no need for any extra bracket or supporting structures at the top of the tank for any one of the cells. Further particularized, the vertical stem of a spigot valve extends upwardly through a vertical passage provided in and through the transverse header so that valve may thus extend directly into operative connection with the associated control device mounted atop the header.

The horizontal jet-emitting pipes are provided with a multitude of jet openings for issuing hydraulic water jets directed at an angle against the solid tank bottom to be reflected therefrom, the jet openings and jets beingso arranged relative to one another and so arranged and directed relative to the bottom that in effect there rises uniformly from the square bottom area of the cell a column of hydraulic water controllable and effective to maintain in the cell a corresponding teeter bed. at the desired density. 1

According to still another feature, some or all of the longitudinally extending submerged partitions are removable so that by means of withdrawal or insertion of such partitions a selected area of a transverse classifying zone can be operated with a selected number of spigot outlets.

In summary, this invention provides a multiple spigot hindered settling apparatus with a horizontal tank having a narrow inlet-end and a wide outflow end, in which sequential hindered settling sizing zones comprise a transverse row or rows of submerged cells or teeter beds representing columns of substantially equal predetermined square cross-section, each of which is defined by submerged longitudinal and transverse bafiie walls disposed at right angles to each other. Each cell or column is served by its own automatic density-controlled discharge or spigot outlet valve. Each cell or column also has its own system of horizontal jet-emitting pipes supplied with hydraulic water by a supplysystem of transversely extending headers through vertical distribution pipes connected to the header for vertical adjustment.

In the drawings:

Figure 1 is a semi-diagrammatic plan view. of the apparatus unit showing the tank partitioned into transverse rows of teeter bed cells, with a system of transverse overhead water supply headers and with density c'ontrol devices supported thereby.

Figure 2 is a side view of the apparatus unit of Figure 1, with a side wall portion broken away to show the 6 on line 3*3 in Figure 3, although modified by the addi tion of individual branch pipe control valves in conjunction with flow control orifices.

Figure 4 is a cross-section taken on line 44 of Figure 1 or 2 showing an enlarged and more detailed vertical sectional view of a cell.

Figure 5 is a, perspective view of the interior of the cell of 'Figure 4, showing particularly the arrangement of the hydraulic water jet emitting means and illustrating the feature according to which they are readily disconnectable and removable from the cell.

Figure 6 is a further enlarged detail view of the bottom portion of the cell sectionally shown in Figure l, to illustrate the spatial disposition of jet-emitting horizontal pipes relative to the cell bottom and relative to one another and the effect of the jets with respect to producing a uniform upfiow of hydraulic water. 7

Figure 7 is a diagrammatic plan view of the tank stripped of everything but the submerged partitions to indicate transverse rows of cells with jet-emitting pipes extending parallel to one another and transversely of the tank.

Figure 8 is a diagrammatic plan view of the tank differing from Figure 7 with respect to the fact that the jet-emitting horizontal pipes at the cell bottom are disposed parallel to the longitudinal axis of the tank, with some of the longitudinal partitions indicated as being removable.

Figure 9 is a cross-sectional view on line 99 of Figure 8 showing modified arrangement of supply connections for the jet pipes.

Figure 10 is a detail side view taken on line 10-10 of Figure 6, showing details of one of the horizontal jetemitting pipes. 1

The apparatus comprises a tank 10 supported on struc" tural I-beams I, the tank having at the inlet end a feed box F adjoining an end wall E1, and having an end wall E2 provided with a transverse overfiow discharge launder D1. The tank has side walls W1 and W2 of stepped configuration as a result of a certain zone-wise subdivision of the tank as presentlyto be defined. Referring to Figure 7 such a side wall, for instance W1 then comprises longitudinal plate- like plane portions 11, 12, 1s, 14 and transverse or shoulder portions V1, V2, V3. Thus the width of the tank increases stepwise from the influent end to the efliuent end, namely from the initial width Y1 to stepwise increasing widths Y2, Y3, Y4; hence the horizontal bottom B of the tank is definable as a plane area consisting of a sequence of rectangular component areas A1=Z1 Y1; A2=Z2 Y2; A3 =Z3XY3; A4=Z4 Y4.

The apparatus comprises the tank 10 subdivided by a system of submerged transverse partitions p1, p2, p3, p4 into transverse zones Z1, Z2, Z3, Z4 each of which zones in turn comprises one or more transverse rows of hydraulic classifying cells or columns. Thus the zone Z1 comprises a cell C of square area defined by sides S preceded by a cell Co of equal width S but of shorter length l. The zone Z2 comprises a single transverse row of cells C2 and C3 defined by a longitudinal partition T1. The zone Z3 is shown to comprise a pair of transverse rows of three cells each, namely, a first row of cells C4, C5, C6 defined by longitudinal partitions T2 and Ta, and a second row of cells C7, C8, C9 defined by longitudinal partitions T4 and T5.

The zone Z4 is shown to comprise three transverse rows of four cells each, namely a first row of cells C10, C11, C12, C13 defined by longitudinal partitions Ts, T7, Ta, asecond row of cells C14, C15, C16, C17 defined by longitudinal partitions T9, T111, T11, and a third row of cells C18, C19, C20, C21 defined by longitudinal partitions T12, T13, T14. Advantage is taken of the steppedcontour of the tank unit 10 of Figure 1, for example by-preparing the tank for shipment in two sections Z4 and Z5, and assembling and connecting these sections at the site of erection.

The side wall W is shown to have adischarge launder D2 along the stepped contour of the wall from point P1 to point P2; the side wall W1 is shown to have a discharge launder D3 along the contour of that wall from point P3 to point P4. Spouts such as shown at U (Fig. 4) may discharge overflowing liquid laterally from the tank into the lateral launders D2 and D3.

Each cell has in the bottom thereof a spigot discharge spout 16 for delivery therethrough of respective groups or fractions of solids called spigot products resulting from the hindered settling operation in each cell. The rate of discharge of spigot product is controlled by mechanism well known of itself, namely a spigot discharge, valve 11 having a valve stem 12 extending upwardly and into operating engagement with an automatic control relay unit M surrounded and boxed-in by a dot-and-dash line L1 (see Fig. 4) which in turn receives control impulses from a primary control unit surrounded and boxedin by a dot-and-dash line L2 and in turn responsive to variations in the height of a clear water column in a vertical open-ended so-called clear water tube 13. According to this invention each cell is provided independently with such mechanism for automatically controlling the rate of spigot discharge in response to variations in density of a hindered settling column to be controllably maintained in each cell and resulting from the flow of the solids suspension passing over the cell in the longitudinal direction of the tank in conjunction with the steady upflow of hydraulic control water introduced at the bottom of the cell. Hence there are provided (see Fig. 1) for each. of the cells Co through C21 respective control relay units Mo and M1 through M21 and respective primary controlnnits O0 and 01 through 021, responsive to the variations in liquid level in clear water pipes R0 through R21.

There will now be described the hydraulic water supply and distributing system which according to this invention comprises an overhead system of supply headers with branch pipes extending from the headers downwardly into respective cells to terminate in horizontal water jet-emitting pipes supported upon the bottom in predetermined spaced relationship thereto and to the walls of the respeclive cells, as well as in predetermined spaced relationship to one another. The jets are directed downwardly against the bottom at a predetermined angle which bears a suitable relationship with respect to the distance of the jetemitting pipes from the bottom and the number of jets and their disposition relative to one another, so that, there rises from the bottoma flow of hydraulic water at a rate which issubstantially uniform across the floor area of the cell, and in effect provides the hydraulic upflow conditions requisite for controllably maintaining a teeter bed of the kind that in prior practice was maintained by introducing the hydraulic water through a perforated or so-called constriction plate from a supply chamber therebeneath.

The overhead hydraulic water supply system comprises a horizontal main supply header 14 coextensive with the longitudinal extent of the tank and is fed from an overhead gravity tank 14 through a standpipe 14 and a control valve 14; the main header'14 has a series of parallel lateral branch headers extending horizontally transversely of the tank, one such branch header to extend over each transverse row of teeter bed cells. Thus, a branch header 15 provided with control valve 15 extends over cell Co; a branch header 16 having a control valve 16 extends over cell C1; a branch header 17 having a control valve 17* extends over cells C2 and C3; a branch header 18 having a control valve 18 extends over C4, C5, C6, a branch header 19 having a control valve 19 extends over cells C7, Ca, Ca; a branch header 20 having a control valve 20 extends over cells C10, C11, C12, C13; a branch header 21 having a control valve 21 extends over cells C14, C15, C16, C17; a branch header 22-having a control valve 22 extends over cells C18, C19, C20, C21.

All the branch headers are mounted';upo11- and supported bythe side walls W1andWz of the tank, for'example as by brackets 23 indicated in Figures 3, 4 and 5. The branch headers in turn support and have mounted thereon the above-mentioned automatic control devices M and O for regulating the rate of spigot discharge.

In this connection, it will be noted that in each cell the stem 12 of the spigot outlet valve 11 extends upwardly through a vertical passage 24 (see Fig. 5) provided in the associated branch header, so that the stem may conveniently reach therethrough into operative engagement with the relay control unit M mounted atop the branch header itself.

Each cell receives its supply of hydraulic water from its associated branch header by way of a pair of lateral downwardly directed elbows 25 and 25 which in turn are each disconnectably connected to vertical pipes 26 and 27 by means of respective rubber sleeves or lengths of rubber hose 28 and 29 secured as by clamping rings 28 and 29 respectively. The vertical pipe 26 terminates at its lower end in a pair of downwardly inclined branch pipes 30 and 31 constituting with pipe 26 an inverted Y- shape. The inclined branch pipe 30 in turn connects with a horizontal jet-emitting pipe 32 and the inclined branch pipe 31 with a horizontal jet-emitting pipe 33, the horizontal jet-emitting pipes 32 and 33 being spaced apart from each other a distance d1 and the pipe 32 a distance d2 of about /2d1 (see Fig. 6) from the associated vertical partition or wall of the cell. The perspective view of Figure 5 is taken substantially in the direction of arrow Q in Fig. 1.

Similarly, the vertical pipe 27 terminates at its lower end in a pair of downwardly inclined branch pipes 34 and 35 constituting with pipe 27 an inverted Y-shape. The inclined branch pipe 34 in turn connects with a horizontal jet-emitting pipe 36 and the inclined branch pipe 35 with a horizontal jet-emitting pipe 37, the horizontal jetemitting pipes 36 and 37 being spaced from each other the distance d1 the same as the distance between horizontal pipes 32 and 33 and the same as distance d1 being provided between horizontal pipes 33 and 36. The horizontal jet-emitting pipes 32, 33, 36, 37 are spaced a distance d3 from bottom B, such spacing being provided by cradle-like supporting brackets 38 (see Fig. 6). Each of the jet-emitting pipes is closed at its ends and has two symmetrically disposed longitudinal rows of jet orifices, namely a row 39 and a row 40 so arranged that the jets from these orifices issue at an angle v against the vertical. The spacing dz between a jet-emitting pipe and the adjacent cell wall is equal to about /zd1 or onehalf of the spacing of the jet-emitting pipes from one another, and the spacings d1, d2, ds and the angle v of direction of the jets all being so related to one another as to produce as a net result and, in effect a flow of hydraulic water rising from the bottom at a rate which is substantially uniform over the floor area of the cell, as jets impinge upon and are deflected by the bottom as indicated by the pattern of arrows *A" in Figure 6. An effective angle v to produce the desired results is on the order of 20 against the horizontal for a distance d3 which is on the order of 1 /2 inches between the jet-emitting pipes and the tank bottom, while the bottom area of a cell may be on the order of 2 /2 feet square.

A transverse stilling or perforated curtain baffle plate K1 (see Figs. 1 and 5) is shown to be placed across the horizontal path of the slurry where it traverses the partition p1 from zone Z to Zz. The baffle plate has perforations K3 in suitable number and of suitable size, and is dimensioned and positioned in such a manner as to compensate for the hydraulic effects of any such change of flow cross-section as may be due the stepwise widening of the tank because of the stepped configuration of the side walls of the tank.

In distinction from the Figure 7 diagrammatic plan view, the Figure 8 embodiment shows a ditference in the arrangement of horizontal jet-emitting pipes j and it insofar as these pipes are disposed to extend in a direction at right angles to that of the corresponding pipes j and i1 shown in the Figure 7 embodiment, namely in a direction whereby these pipes are coextensive with the longitudinal axis of the tank, with the spacing of these pipes from one another being the same as in the Figure 7 embodiment. Another distinction to be noted in the Figure 8 embodiment lies in the fact that some of the longitudinal partitions N1 as well as the transverse partitions N: are shown to be upwardly removable from the tank as by virtue. of guide grooves indicated at G. With component wall portions of the partitioning system thus removable this Figure 8 embodiment provides a variety of modes of operation which make it possible to consolidate operatively into a single teeter bed two or more cells or columns of a transverse row, or even to thus consolidate one transverse row of cells with an adjoining row into a single teeter bed served by a plurality of spigot discharges and spigot discharge control units. Also, for example in case of failure of the spigot discharge control unit of one cell, a suitable partition may be removed so that the control unit of the adjoining cell in the row may be employed to serve both cells constituting a single teeter bed.

If, for example, all of the longitudinal partitions N1 in the last row of cells be removed as is indicated by the dotand-dash line showing of these partitions in Figure 8, there will then present itself a series of horizontal jet-emitting pipes j and f1 equidistantly spaced and uninterrupted from side to side of the tank.

The Figure 10 side view of a jet-emitting pipe I shows the pipe to comprise a pair of end sections J1 and J2 screwed into an inverted T-fitting J3, each section J1 and J2 having at the underside two rows of jet orifices disposed in a manner similar to the orifices shown in Figure 6. The number and the size of the orifice in a row and their spacing from one another may differ from transverse row to transverse row of cells because of the differences in hydraulic operating conditions required to produce the desired solids sizing and classifying ettects upon the slurry as it traverses the rows of cells from influent end to effiuent of the tank.

Figure 3 shows a modification with respect to the vertical branch feed pipes 26 and 27 of Figure 3 and Figure 5 in that a horizontal feed header 16' has a pair of downwardly extending branch feed pipes 26' and 27' each of which is provided with. a control valve 26" and 27" respectively as well as with flow control orifice member 26 and 27 respectively. The provision of these additional control means permits eifecting additional and individual control of the rate of flow to be carried steadily by respective vertical branch feed pipes which supply the jet-emitting horizontal pipes at the bottom of respective sizing compartments. That is to say, after the branch control valves 26" and 27" have been set to provide suitable valve passage area, the orifice members 26 and 27 will then exercise an automatic control etfect whereby the rate of flow passing to and through the vertical branch pipes is automatically maintained at a desired value irrespective of moderate fluctuations of pressure in the branch header 16. That is to say, within reasonable limits such flow controlling means as the valves 26" and 27" and the orifice members 26 and 27 interposed in the respective branch feed pipes 26 and 27' will serve to maintain substantially constant a desired rate of flow in the branch pipes even though pressure conditions in the supply header might vary.

Operation In the operation of this apparatus the feed of slurry to be subjected to classification treatment passes from feedbox F where it receives diluting water if necessary, over I the submerged feed partition fo across a preliminary cell Co where the rate of upflow of hydraulic water issuing in the form of jets from jet-emitting pipes i1 is adjusted by means of valve 159. to have an 'upfiow' intensity sufiicient to permit ,substantially the largest size only to be intercepted while the density of the teeter bedrequisite for efiecting such selective interception is automatically maintained by the spigot discharge control units M0 and O0 in conjunction with clear water pipe Ru. That is to say, as the density in the teeter bed varies it will produce corresponding variations of liquid level in the clear water pipe and these variations in turn will by their hydraulic pressure variations influence the primary control unit 00 which in turn actuates the relay control unit Mo adjusting the spigot discharge valve 11 to allow the escape of a quantity of solids sufiicient to restore the density of the teeter bed as maintained by the upflow of the hydraulic water supplied at the bottom of the bed. In other Words if the density is too great the spigot valve will rise sufficiently to reduce the density and if the density is too low the spigot valve will lower sufliciently to effect upward correction of the density.

The flow of slurry minus the coarsest size solids continues horizontally across the submerged partition po and across cell C1 where again a less coarse fraction of solids is intercepted and is isolated from the slurry by establishing and maintaining in the cell the requisite density of the teeter bed therein, such density being automatically maintained as by the rate of hydraulic water supply through control valve 16a in conjunction with automatic control of spigot discharge from that cell by means of the primary control unit 01 and a relay control unit M1 responsive to the liquid level fluctuations in the clear water pipe R1. The slurry minus the solids fraction as presented by the spigot discharge from cell C1 continues across the transverse partition p1 while fanning out over the zone Z2 (that is area i2 y2) comprising cells C2 and C where again a density of the teeter beds is maintained in the teeter beds therein requisite to produce from them spigot discharge products which represent the next smaller size fraction of solids desired, the density of these teeter beds and the spigot discharge products therefrom being controlled by the rate of hydraulic water supply from control valve 17 coupled with the control function of the spigot discharge control units M2 and O2 and of clear water pipe R2, and of spigot discharge control units M3 and 03 with their clear water pipe Rs.

The slurry minus the spigot discharge products from cells C2 and C3 then continues across the transverse partitions p2 and p3 fanning out over the zone Z3 (i. e. area i3 y3) comprising the two rows of cells C4, C5, C6, and C7, C8, C9 respectively. Again the next smaller size solids fraction selectively intercepted from the slurry by these cells is obtainable by way of the spigot discharge products from the cells C4, C5, C6 being regulated by their re spective spigot discharge control units M4, M5, M6 and O4, O5, 06 with their respective clear water pipes R4, R5, R6, the cells being supplied with the requisite amount of hydraulic Water through control valve 18 The operation of the second row of cells C7, C8, C9 of zone Z3 is similarly conducted and controlled to have them yield a classified spigot discharge product representing the next smaller size fraction of the solids.

Again the stream of slurry minus the preceding spigot discharge products fans out across the transverse partition p4 then further across transverse partitions 125, pa in zone Z4 (i. e. area i4 y4). The next smaller size solids fraction is thus selectively obtained by way of the spigot discharge products from the first transverse row of cells C10, C11, C12, C13 in zone Z4, the next following smaller size fraction is obtained by way of the spigot discharge products from the second transverse row of cells C14, C15, C16 of zone Z4. while the last and smallest size fraction is selectively obtainable by way of these spigot discharge products of the third transverse row of cells C17, C13, C19 of zone Z4, whence the carrier liquid of the slurry containing residual fines may pass from the tank by overflowing into the efiluent launder D1. The requisite teeter bed densities in the respective transverse rows of cells in zone Z4 and the desired size spigot discharge, products from the respective rows are controllably obtainable in a manner similar to that described for the preceding zones Z1, Z2, Z3, namely by means of suitable rates of hydraulic water supply through the control valves 20 21*, 22 in conjunction with automatic spigot discharge control by the respective control units for the respective cells.

Figure 9 resembles Figure 3 except for the fact that it provides vertical branch feed pipes 4-1 and 42 leading directly oif the underside of the associated horizontal transverse water supply header, the vertical branch pipes being provided with disconnectable sleeves 43 and 44, each vertical branch pipe to supply its pair of horizontal jet-emitting pipes jz.

The desired uniform rate of hydraulic water rising from the fioor of the respective cells is attainable by proper correlation of the spacing of the jet-emitting pipes from one another and from the number, size and disposition of the jets issuing from these pipes, and the vertical spacing of the pipes from the cell bot-tom. For example, for a given equidistant horizontal spacing of the pipes and given number, size and disposition of the jet holes, the desired uniform upward flow effect may be attained by adjusting the vertical spacing of the pipes. relative to the tank bottom as by a change of brackets 38. When difierent operating requirements call for a change in the size, or number or disposition of the jet orifices, the vertical branch feed pipes may be disconnected by unfastening their respective sleeve or similar connections, removing them, unscrewing the horizontal end sections it and i2 and replacing them with substitute sections having for example different size jet orifices, then re-inserting them in respective cells and reconnecting them with their respective transverse supply headers.

I claim:

1. A hindered settling apparatus having a tank providing a horizontal sequence of solids-classifying zones of respectively increasing average width in which a liquidsolids feed mixture carrying a Wide range of solids sizes from coarse to fines, in passing sequentially in a horizontal stream over said zones from the narrow influent zone to the wide efiiuent zone is classified into intermediate size ranges issuing as spigot products from the bottom of respective zones, while a teeter bed is maintained at a desired density in each zone by supply means providing a controlled upflow of hydraulic water therein as well as by corrective control of a spigot outlet valve, and in which automatic density-responsive control devices are provided for each zone for so correctively actuating the spigot outlet valve as to automatically maintain said desired density; characterized thereby that the tank is provided with a submerged system of longitudinal partitions at right angles to said transverse partitions and disposed to subdivide the space between each pair of transverse partitions into a transverse row of columnar cells of substantially square cross-section and of substantially identical size, so that the infiuent end of the tank comprises a single initial such cell whereas the effluent end portion comprises a multiplicity of such cells in a transverse row, each said classifying zone having one more cell than the preceding zone so that each side wall of the tank presents a plan view of stepped lateral contour with both contours being substantially symmetrical to each other and each step of each contour being the equivalent substantially of one-half of thewidth of. a cell, with the addition of hydraulic operating water supply means comprising a plurality of stationary horizontal pipes substantially rectilinear and parallel to each other, each pipe having along each side thereof a row of orifices disposed for emitting jets of operating water obliquely towards the tank bottom, yet in a direction substantially perpendicular to the longitudinal axis of the pipe, overhead conduit means for supplying operating water, downwardly extending branch conduit means connecting said overhead means with said horizontal jet-emitting pipes, control means for regulating the supply of operating water to said jet-emitting pipes, the number of said jet-emitting pipes, their spacing with respect to one another, as well as. with respect to the boundaries of respective cells, and the number of jets issuing from each pipe and their angle of incidence relative to the bottom, and the volume of water supplied to the jets being such that there is obtainable in effect an upflow of operating water from the bottom substan-. tially uniform across the cell, with said water control means as well as said automatic density-responsive control devices being independently settable with respect to each other for maintaining a desired density in respective cells whereby to obtain desired size fractions from respective transverse rows of cells.

2. Apparatus according to claim 1, in which said branch conduit means are provided with disconnectible pipe connecting means for effecting vertical adjustment of the jet emitting pipes relative to the, bottom and relative to the overhead conduit means, with the addition of bottom supports defining the distance between the jet emitting pipes from the tank bottom.

3. Apparatus according to claim 1, in which the water supply means for one transverse row of cells comprise an overhead supply header coextensive with said row, and the branch conduits comprise for each cell of said row a pair of branch conduits disposed to straddle the spigot valve, each branch conduit in turn terminating at its lower end in a pair of branches constituting an inverted Y-shape with the horizontal jet emitting pipe being provided for and connecting substantially at its middle to the end of a respective branch of said inverted Y-shape, with the addition of bottom supports defining the distance between the jet emitting pipes and the bottom, with a pair of such pipes disposed at each side of the spigot valve and with the further addition of disconnectible pipe connecting means between each branch conduit and said header.

4. Apparatus according to claim 1, in which said branch conduit means are provided with disconnectable, flexible tube connections for effecting vertical adjustment of the jet emitting pipes relative to the bottom and relative to the header, with the addition of botom supports defining the distance between the jet emitting pipes and the bottom.

5. Apparatus according to claim 1, in which the water supply means for one transverse row of cells comprise an overhead supply header centrally coextensive with said row, and the branch conduit means for a cell comprise a pair of lateral downward pipe elbows extending symmetrically from respective opposite sides of said header, a vertical branch pipe for each elbow, each vertical pipe having at their lower end a pair of branch connections constituting an inverted Y-shape disposed in a plane extending transverse of the header, with a horizontal jet emitting pipe being connected at their middle to the end of each branch of said inverted Y-shape and thus being disposed substantially coextensive with said header, so that a pair of such jet emitting pipes is disposed at each side of the spigot valve, and disconnectable pipe connecting means between each elbow and its respective vertical pipe.

6. Apparatus according to claim 1, in which the water supply means for one transverse row of cells comprise an overhead supply header coextensive with said row, with the addition of mounted means provided upon said header for supporting thereon the respective density responsive control device for respective cells.

References Cited in the file of this patent UNITED STATES PATENTS

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