US2980934A - Sediment eductors for settling chambers - Google Patents

Description

April 25, 1961 R. T. s'rElNDoRF SEDIMENT EDUCTORS FOR SETTLING CHAMBERS 2 Sheets-Sheet -1 Filed June l2, 1956 April 25, 1961 R. T. STEVINDORF 2,980,934

SEDIMENT EDUCTORS FOR SETTLING CHAMBERS Filed June 12, 1956 2 Sheets-Sheet 2 INVENTOR i2. zm'ndwy:

' ATTOEY 1 2,930,934 sEDmENTYEnUCToRs FOR sE'rrLnsG CHAMBERS,

' Robert T. Steindorf, Milwaukee, Wis., assigner-Ato Chain Belt Company, Milwaukee, Wis., a corporation of Wiscousin d l Filed rune 12,- 1956, ser. No. 590,939

L 3 claims. (c1. 15-1.7)

` fThiSinvention relates tov sediment eductors for settling chambers such Yas are widely employed in sewage disposal, Aliquid purification and analogous work, and it has for its principal object the provision of an improved eduction device which is less expensive to construct and more ecient in accomplishing the removal of settled matterfrom theifloors of said chambers than have been the eductors heretofore proposed.

t Although byV no means specifically limited thereto, the

present eductor may be advantageously employed with Vsedimentation apparatus `such as that disclosed in prior U.S. 'Patents No. 1,947,429 to Townsend and Brower, and No. 2,150,865 to `Shafer and Seidenstricker, and therefore for purposes of disclosure the invention'has y been illustrated in thetaccompanying drawings in connec- `cation ofl suction tothe tubes orl `discharge duct.

The instant inventionputilizes in part the principles disclosed and claimed in an application filed concurrently herewith by my co-workers Arthur C. Lind and William 1.1" Kat'z, Serial No.l 590,940 filed concurrentlyv herewith and `entitled Method and Apparatus for Removingv Sedimentff/ d H n theabove mentioned drawings; t

Figure l"is a central vertical sectional'view, partlyV in elevation, of a typical settling tank and sediment removal apparatus such as is disclosed in the above identitied patents with the said removal apparatus` however,

c qui pedfwith one form of sedimentzeductor constructed inaccordance with this invention;

Eig. 2 is an enlarged plan view, partly broken away and in section, of the eductor and immediately associated parts shown in Fig. 1; 1 d l Fig. 3 is a front elevational view of theparts illustrated Vin Fig. 2;

Figs. 4, '5, 6 and 7 are enlarged cross sectional Views of the eductor, taken respectively on the planes `indicated i by the lines 4-'4, 5-5, 6,-6 and 7f7 in Fig. 3, looking in the direction of the arrows;

Fig. 8 is a perspective view illustrating a preferred,

-V although not the only, mode of constructing the eductor;

Fig. 9 is a plan view of a slightly modified example ofA the invention; Fig. l() is a front elevational view of the eductor shown in Fig. 9; N s

t Fig.A -ll is a cross sectional view on the plane'indicated by the line 11-11 in Fig. 10, looking in the direction of the` arrows; and; l l

` fied Sites Patent f Figs. 12 Aand 13 are views illustrating modified cross sectional shapes the eductor may take.

Referring more particularly to Fig. l, 15 indicates a sedimentation tank into which the liquid to be clarified is introduced through an influent conduit 16 and central feed. well 17. The clarified liquid is discharged over a weir '18 to an effluent launder `19 provided at the top of the perimetric wall 20 of the tank and communicating with a discharge duct, not shown. The tank oor 21 slopes slightly from said wall to the center of the tank to facilitatedrainage ofthe tank, and a sediment discharge conduit 22 extends through said floor radially from such center. An eduction manifold 23, surmounting and communicating with the inner end of said conduit 22,is appropriately journaled on thetank floor for rotation about a vertical axis and has one or more hori-` zontally extending Vsediment eduction tubes 24 connected toits branches 25, one being shown. A tubular shaft 26 is secured to ,andextends upwardly from the manifold 23 whereby it may be rotatedby means of a suitable source of vpower and speed reduction mechanism 27 to slowly traverse the education tube 24 over the tank floor 21. When only one eductor tube is employed, a counter- Weight 28 preferably issecured to the opposite manifol branch 2S to balance the apparatusf` Whereas in the constructions shown in the two prior patents mentioned the sediment eduction `pipes were of circular cross section and were disposed a substantial distance above theV chamber floor, with collecting nozzles depending from them to adjacent said iioor, the eductor tubes'A of the present invention are essentially of noncircular cross section and extend over the tank Hoor in adjacent ,substantially parallel relation to the surface thereof. Thus,` as willbe readily understood from Figs. 2-11, the tubes there shown are of a rectangular cross section which provides four planar walls 30, 31, 32 and 33, Vand said tubes are canted about their longitudinal axis so that when viewed incross section, as in Figs. 4-7,

Y each of the said Walls is inclined to the horizontal. With -iri lieumthereof the lower forward wall 3170i the tube is' provided with one or more sediment admission ports 34. As here shown,V a series of such ports is providedA adjacent thel lower edgeof said wall, and in accordance with the teachingofA theV Townsend et al; Patent No.

1,947,429 they' pregressiveiy increase in size from the inward end of the tube to` the outward end'thereof; this for the reason that the respective zones from which the ports receive sediment increase in area in proportion to their distance from the axis of rotation.

As the tube is moved through the liquid and sediment at the bottom of the tank, the downwardly inclining wall 31` with its forwardly facingV ports 34 greatly facilitates the v jentry of the sludge into the tube. Howeverit has lalso lbeen .foundithat the eliiciency of an eductor constructed as above described'may be further appreciably enhanced if a lip or flange 35 be provided below the ports 34, such ange being reversely inclined with respect to the wall 31 and extending forwardly and downwardly to proximity with the tank floor. The convergent surfaces of said wall and flange tend to fluidize the sludge blanket as the eductor moves through it, whereby Vthe sediment passes to and through the ports 34 even more readily, with theres'ult that substantially complete removal is effected and the floor area immediately behind the moving eductor is practically free of sediment.

Since the volume of sediment in the tube of course increases *from theA outwardend to the inward end thereof with the addition Vo f each vincrement entering through the successive ports 34,*the cross sectional area ofthe eductor should increase in like direction if a uniform velocity of sediment flow isto be maintained throughout the tube, which is desirable. lThe present eductor may be readily constructed to provide substantially uniform variation of its cross sectional area from end to end, with resultant optimum functioning.

Fig. 8 illustrates a preferred, although no t'the only, mode of constructing a rectangular eductor tube vsuch as above described. v That is to say, a rolled ory pressed channel member of appropriate length is provided, the web 32' of which is of uniform width from end to end. The legs 30 and 33 of said channel however, are of substantially uniform tapering depth from end to end, asl shown, with the leg 33 beingof greater depth than the leg 30. A strip 3 1 of uniform width throughout, and having theports 3.4 'drilled orpunchedin it,.is positioned between and welded to the legs 30 and 33 of thechannel, such strip being disposed in transverseA parallelism with the web 32 of the channel and with its forward edge substantially ush with the tapering edge of the channel leg 30', and its rearward edge spaced from the tapering edge ofthe wider channel leg 33', thereby providing the longitudinal flange 35 extending the full length'of-the tube. A transverse filler piece 36 is provided at the narrow end of the channel whereby to close; the outward end of the eductor. v

Referring again to Figs. 2 andV 3, at its larger end the eductor tube has attached to it -a short converter section 37 which changes the crosssection from rectangular to circular, and said section 37 in turn is secured to one end of an S-shaped pipe 38 the other end of which is attached to the branch 25 of the manifold 23a.y A spiral scraper blade 39, surrounding the base of said manifold androtatablertherewith, insures that matter' settling inv the central portion of the .tank adjacent the manifold scraper blades 40 which deflect the sediment horizontally on the tank oor intothe paths of such ports as the eductor is moved over the oor. In these gures the eductor is arranged for clockwise rotation whereas in Figs. l-7 the eductor moves counterclockwise.A

While a quadrilateral formcf eductor tube has been l specifically described above, bther non-circular cross sections may be employed, such for examplela's the trispectivelgnv What is claimed is: Y n 1. A sediment eduction tube for substantiallyhoril angular forms 24@L and dzllfifshown in Figs. 12 and 13 rezontal disposition adjacent andunidirectional movement over the door of a sedimentation lchamberfsaid tube being of a quadrilateral vcross sectionhproviding a pair of downwardly divergent sediment dellecting upper walls, and an inclined forward wall which is provided with sediment admission ports adjacent its lower `edge and with a longitudinal' flange projecting'forwardly below said ports. A Y l LA ksediment eduction tube' for substantially horizontal disposition adjacent andl unidirectional movement over `the floorofa sedimentation chamber, said tube havling a substantially uniform longitudinal taper, and being of a rectangular cross section providing a pair of downwardly divergent sedimentdellecting upper walls, and a pairof :downwardly convergent lower walls one of which is ported along its lower edge for the' passage of sedi-Y ment therethrough and thefother of which isY extended beyondk such ported wall to provide a longitudinal a'nge therebelow. v v Y.. rf 3. An eduction tube for sdinentationchambers, comprising an elongated channelmember of uniform width,

the legs'of which taper in depth substantially uniformly from en dtorend and oneof whichY is'wider than the other; and a-wall member having' a series of longitudinallyv spaced ports, disposed Vbetweenand `secured to said .-channel' legs in substantially the plane of vthe'edge of the will be moved outwardly into the path of the inward depositing and building up thereon. This is of impor' tance in sewage disposal, where the settling solids are highly putrefactive with attendant disagreeable odors.

The eductor above described is especially adapted for the removal of activated sludge and other light s edi-` ments in largeVOIume,

shown in Figs. 9, 10 and 11 may be advantageously em, ployed. y In this case the general construction of the tube may be the same as described above except that fewerV Where lewer volumes, ausl/or)k heavier sludges are to be dealt with the modified form;

sedimentadmission ports 34 are provided; and the tube f has attached to it aV plurality of4 V- shaped plows vor;

narrower leg, whereby a portion of the wider leg projects beyond salidgwall member to provide a longitudinal ange adjacent the ports of the latter, the areas of said ports progressivelyincreasing as the cross sectional area .of the-tube decreases. Y l

K 'References'.itediin the le of this patent c UNIrEDjs'rArns PATENTS I 11,101,541

naningion f June 30, 1914 2,081,597* f -Nowak j MayZS, 1931 2,143,441 Jacobs Ian. 10, 1939 2,150,865 Shafer eral, ,Ma. r. 14, '1939' .20,3718 Australia Aug-7'; 193s

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