Патент USA US2411390код для вставки
Nov. 19, 1946. F. D. PRAGER 2,41 1,390 LIQUID TREATMENT Filed April 3, k1944 fil ` uw, INVEN TOR. ov.' 19, 1946. 2,411,390 F. D. PRAGER LIQUID TREATMENT Filed April :5, 1944 ` 2 Sheets-Sheet 2 uw, INVENTOR. Patented Nov. 19, 1946 2,411,390' ' UNITED STATES PATENT OFFICE LIQUID TREATMENT Frank D. Prager, Chicago, Ill., assignor to Graver Tank & Mfg. Co., Inc., a corporation of Dela Ware Application April 3, 1944, Serial N0. 529,333 13 Claims. (Cl. 210-16) l 2 This invention relates to liquid treatment and particularly to the removal of` impurities from of the tank.« The lower` part of the column is im perforate but a number of steel pipes 28 commu nicate with the lower part of the downfiow zone liquids by precipitation, aided by sludge filtra tion and recirculation. It is an important object of this invention to improve over previous devices for distributing liquid> flows to be exposed to sludge filtration, particularly in large tanks. It is one Aparticular object hereof to transfer - I8 within the hollow column and extend radially below the grouted surface I5 toward the wall I2. These radial steel pipes form how passage means, as will be explained, and also serve to reinforce the concrete bottom I I ; suitable reinforcing wires 2I being ' provided between these radial -pipes liquid mixed with chemicals and sludge from the 10 `within` the concrete bottom: II, and having their central to the peripheral part of a treatment tank ends welded to the pipes.> In earlier construc tions, somewhat similar flow passage means were in a manner involving the least possible obstruc tion to the necessary flows in the clarification and sludgefiltration zone contained in the tank. Another particular object is to transfer such materials from-a central to a peripheral part in installed in upper parts of the tank.> When so in-- , stalled they obstructed the upward flow in said upper parts; they tended to interfere with cer taindesirable types ‘of rotating scraper- assem-4 a manner which allows the use 'of an emcient _ blies; and moreover their installation in such and economicalÍ type of sludge scraping equip upper parts involved expensive means and meth ment» ods of construction. ¿The absence of such pipes Another object is to provide improved inlets 20 in the upper part of the tank is one of the advan . or outlets in an annular channel zone surround tages of the present invention. ing a sludge filtration tank.Adjacent to the concrete column I1 and con Still other objects will appear from the follow centrically surrounding the same I provide a steel ing description. drum 22. forming an upñow zone 23 between this In the drawings, ' drum and the column. This upflow zone com Fig. 1 is an elevation, partly in section, of one municates with a lower, central part of the tank, embodiment of this invention. by means of the lower, open end 22-A of the Fig. 2 is a plan view of the apparatus of Fig. 1. drum 22. The two zones I8 and 23 may be re-` Fig. 3 is a partial section, along- lines 3-3 in ferred to as parts of a'central now collecting Fig. 2; and 30 zone, in view of the operation to be described Fig. 4 is a fragmentary, sectional elevation of hereinafter. The two members I'I and 22, which a modified embodiment. . are centrally located, annular wall means con-- Y The tank I0 has a flat circular bottom I‘I of reinforced concrete. The side wall I2 ls cylindrical . and made of steel. A'lower portion I8 of the 3.5 wall is an inverted cone frustum vmade of -con crete, upstandingrr from the periphery of the bot tom II. The bottom II has a slight inward slope to facilitate an occasional draining of the tank. A thin layer of fine grout I6 forms the upper part 40 of this bottom; this grout being applied in a . plastic condition when the „rough concrete work has been completed. A proper, dat or smooth top ñning said rspective zones, are similarly classifi able as parts of a central flow collector means. Thelower, open end 22-A of the drum 22 forms the inlet of this flow collector means I'I, 22, or more specifically, the inlet of the upñow- portion thereof. Concentrically with the wall I2 and adjacent this wall I provide a large steel drum, baille, wall or‘,l partition 24. forming an annular peripheral channel zone 25 between the wall I2 and the drum 24. The drums 22 and 24, or parts integral therewith, extend downwardly, respec surface I5 of the bottom, for the uniform accu- ' tively, to points‘28 and'2l at suitable elevations mulation and quiescent scraping ofi’ of settled 45 above the surface I8. ak clarificationl zone or sludge, is obtained by rotating the sludge scraper assembly I8 over this grout before the grout has chamber 28' is formed by and within the outer drum 24, outside the inner drum 22. This clari solidiñed. 'Thereafter the sludge scraperlmassem bly is raised a fraction `of an inch. iication zone has much greater area and volume - b - Concentrically. with the tank, a concrete co1 umn Il extends upwardly from the bottom II. This column, and the central part of the bottom 5°, ties, as will be explained hereinafter. below it, are hollow, providing a cylindrical, -‘central downilow zone I8.„’Openings I9 are provided in the top of the column, slightly below the top than the peripheral channel 28, which in turn is considerably larger than any of the other zones of the tank, in orderl to insure proper flow veloci 55 , The downfiow zone I8 receives raw liquid thru the II into inleta pipe ‘ part29'ofwhich this zone, entersabove thru the the bottom ` ‘ 2,411,390 3 4 thereof, centrally of the inner ends 2li-A of the several steel pipes 2l). Thus the flow from ' the inlet pipe` is uniformly distributed to the several pipes 2B. These pipes 28 discharge into . l through the openings I9 down thru the central downñow Zone I8 in the hollow column; then ' the peripheral channel 25 through discharge outwardly thru the radial steel pipes 20, then around the peripheral channel 25, with local 4up and down currents,"then`inwardly and rotatingly openings 30 which are uniformly distributed along the channel and which are located above -the lower limit 21 of the outer drum 24, but be low the top of the tank, Adjacent each opening ` 30 the respective steel pipe 28 merges intoA a dis y and suction below the same. As a result, a stream yof air and liquid rises in the upiiow zone 23; air escapes at the top of that zone; liquid ñows over the bottom of the clarification and sludge 10v charge chamber 3| cored into the concrete of the conical wall I3 and discharging into the periph :ed zone, and finally back into the upiiow zone 3. . The velocity of this >circulation is suitably reg ulated by control means, not shown, in the sup plyl line for compressed air leading to the airy directions, about 45 degrees inclined from the horizontal. As a result, the liquid is injected-into 15 lift device 38, y,in manner known from earlier construction. The several parts of the tank are the peripheral channel in a plurality of inclined so dimensioned that the circulating ilow is rela-' jets, tending to produce a general horizontal r0 tively rapid in the up and downflow zones and in ` tation, and local up anddown agitation of the the radial pipes, suitably slower in the peripheral liquid in the peripheral channel. >This jety action with up and down agitation is 20 channel, and still slower over the bottom of the sludge bed zone.l In general, the aggregate or to substantially confined to the peripheral channel, tal iiow area of the several pipes 20 equals the by virtue of the aforementionedouter drum 24 area of theK downiiow zone and this in turn equals extending to _the level 21 below the discharge v eral channel 25 in uniform upward and lateral openings 30, but the general horizontal rotation the area of the upflow zone, these areas being so dimensioned that with proper amounts of liquid recirculated, the liquid velocities thru these areas amount to about 2 feet per second, with at least enters this zone thru a long and wide slot 32, 50% variation plus or minus, depending on local . between the surface I5 and the lower edge of the conditions. The velocities in the peripheral chan outer drum. Accordingly, the liquid tends to con tinue its rotation in the bottom part of the clari 30 nel and over the bottom 0f the tank generally range downward from '1 foot per second to only , ' in the peripheral channel tends to continue in ,the clarification zone 28, .as the rotating liquidv fication zone 28, but this continued'rotation can _ be prevented, or can be deñected into vertical a few inches, or sometimes fractional inches per second. In the upper parts of the peripheral channel and clariñcation zone, the preferred ve bailies 33 which are known from earlier construc-tions. Such deiiecting baffles can be located at 35 locities amount to only a few inches per minute, `at most. However, a. somewhat higher velocity and extend to any desired points outside or in and agitation can be tolerated in the top of the side of the large drum 24, depending on whether channel, which serves for scum release, than in the sludge formed in the process„and to be sus the clarification zone, due to the relatively rapid pended in the sludge bed. is relatively light or rising rate of even minute air bubbles agglomer 40 heavy, requiring Vmore or less of saidvertical ated with scum particles. circulations in the clarification zone 28. A sus Any chemical re-agents needed to precipitate circulations, and ultimately stopped, by deiiecting pended sludge bed 34 is provided and maintained the sludge are added to the circulating liquid by the pipe 33 terminating adjacent the top ofthe the liquid percolates thru the sludge bed, in a zone, Where rapid and complete mixing is generally upward direction. Treated liquid _is 45 upflow insured by vanes 40, deiiecting the rising stream withdrawn above the sludge bed 34 by overñow of air and liquid into a horizontal rotation, in the inthe clarification zone in known mannen'and . weirs 35 with effluent launders 36 of known con top of the upflow zone. These vanes and the hor g izontal liquid rotation which they set up, serve Once that the tank is ñlled the weirs 35 pre also to dampen any surges of the air and liquid vent the liquid level 31 from falling below said 50 stream, whereby they prevent any drops of liquid ' weirs. The liquid level 31 is prevented from rising above the top of the tank by conventional - from being projected upwardly over the top of the control means, not shown. 'I‘he inner drum 22 The circulating liquid, which' carries any re extends above the liquid level 31, and the outer drum or baille 24 _is integral with one wall 24-A 55 quired chemicals, spirals down the central zone within thel hollow column, and meets the raw of the outermost Alaunder 36, which wall also liquid entering the inlet pipes to be mixed with extends above the liquid level 31. By means of -the same. _Mixing energy and turbulence is in this arrangement, the peripheral channel 25 and sured by the iiow velocity of the circulating liquid, the central upflow zone 23 communicate with the clarification zone 28 only in °the lower parts 60 and any continuing rotation thereof. Due to thisturbulence, the ’several constituents are inti thereof. .This forces all of the ~rotating liquid mately mixed in the bottom part of the downñow ' from the peripheral channel to enter the bottom zore. Turbulence and agitation continue in the of the clarification zone, and similarly, all liquid vradial flow passages 20. Agitation'with suitably withdrawn into the upiiow zone is removed from lower velocity prevails in the peripheral channel the bottom of the clarification zone. 65 and at the bottom of the sludge bed 34, and some The rotary liquid ñow is augmented by a cireu minute agitation continues in the sludge bed it lation, which can also continue during any slow self. The slowest liquid velocities are maintained down or complete shutdown of the inñow thru above this bed, in the large, unobstructed upper ' the pipe 23. _This circulation is established and maintained in well-known manner, for instance 70 part of the clarification zone. Under conditions of overload and the like, there may be a, tendency . by an air lift device 38, mounted on the column for certain sectors or constituents of the- sludge I1 in the lower part of the upflow zone 23, and bed to boil up toward the water level, but due to releasing compressed air into that zone. The the large and unobstructed construction and oth release of air is conducive to the development- of ' relatively high pressure above the airA lift device 75 er features of this apparatus, suchtendencies are struction. 2,411,390 emciently checked and the apparatus delivers treated and clarifiect- liquid- at increased flow rates. as compared with earlier devices operat ing under comparableI conditions. Generally I prefer to control the liquid veloci sludge will rotate in the lower parts of the sludge bed. As a result, the volume of the peripheral channel- 25 can be made smaller, by reducing the width and area' thereof, and adequate fioccula tion is still provided. Desirably, the windows 52 ties in the clariñcation zone so as to allow and force the largest `sludge particles to settle out on are located between the discharge openings 30,l and the solid lower skirts 5| in front of said dis the dat surface I5. Frequently some sludge tends to settle also in the peripheral channel, between the discharge openings _30. In al1 other parts of .the tank, liquid velocities are such as -to prevent sedimentation of sludge. Any sludge sediment charge openings, sothat the up-and-down flows 54, produced by the liquid jets 53'in the channel, may not interfere with the necessary, relatively quiescent conditions inside of the large baille 50. Of course, the liquid iiows 55 entering this inner from the peripheral channel slides down the in clined wall i3 and collects on the flat -surface l5, space may have any desired velocity, depending on the size of the windows 52. together with the sludge from the clarification In order to prevent any settled sludge from col zone 28. All this sludge is scraped from the ñat lecting behind the ,baille skirts 5|, in the periph surface l5 by the scraper assembly I6, which ro eral channel, these skirts do not merge with the tates slowly around the central column H, and tank bottom, but allow the sludge to slide down shifts the settled sludge into a sump M, formed in the bottom il adjacent the central column. 20 the inclined wall i3 and into `the inner space, in a flow shown at 56. . ' From here the sludge is ultimately withdrawn The modified embodiment includes also a sys thru a pipe d2 with suitable, well known controls, tem of auxiliary or alternative iìow passage means not shown. The rotary velocity of the scraper 5l, extending from the central mixing -zone to assembly l 5 is selected to prevent any undesirable stirring up, or deñecting, of sludge and liquid - points above the liquid level 31 and discharging currents in the clarification zone.. recirculated liquid - is supported by bearing'members 43;4 these bear ing members in turn being supported by the hol ‘low column il. By means of this central, ele vated bearing support, the weight lof the scraper assembly, which may amount to- several tons,'is emciently balanced and absorbed. _ into the peripheral channel, ' in directions tangential of the channel, through outlet L fittings 58, whereby the recirculated liq The scraper assembly i6 is fastened to the lower part of the drum 22 which rotates slowly together with the scraper assembly, and which uid can be inspected and sampled. 30 It is often desirable rto provide at least one re circulating pipe 2li with such a sampling arrange ment, for close control over the condition of the circulating fioc. Itis not quite suñcient, in many instances, periodically to sample the lloc in the channel 25, although this should be ‘done also. The scraper assembly is preferably driven by a 35 It is inherent in the' rapid chemical mixing stage, through which the circulating iioc must ' tion, adjacent the side wall l2. It will he noted pass, that the i'loc is broken up to some extent. traction drive assembly/.list of known construc that with the aforementioned prior construction, using distributing piœs in the top oi' the tank, In the presence of proper chemical and pH con ditions, the comminuted fioc is promptly built up it was impossible to provide such desirable and 40 again, as soon as flow conditions of less turbu eí‘ilcient traction drives, inasmuch as the distrib uting pipes interfered with such a traction drive. The general advantages of traction drives are well known and will not be described. A special advantage resides in the fact that such a drive is most conveniently provided with- a scum re moval blade «t5 depending from the outer parts of the traction drive on top of the peripheral lence are established; that is, upon discharge into the peripheral channel. In fact, more settleable ~ ultimate ?locs are formed in this manner than without any breakup of fiocs. With- the modiñed arrangement it is easy to sample both the comminuted iioc discharged at 58 and the re-ñocculated particles in the top of the channel 2d. Such sampling of the commi nuted ?ioc is preferable over the prior method channel 25 and suitably cooperating with a sta tionary scum shelf and trough #6in the same 50 frequently used in plants of this general type, channel (see Fig. 3); both blade and trough gen wherein small sampling pipes, independent from erally. being installed in substantially radial di the main flow passages, are brought to the sev rections across the top of the channel (see Fig. eral ñowsto be sampled. >This earlier method „ 2) and the trough being suitably emptied by a furnishes inderiinite samples. due to the addi pipe di. The chemical treatment, particularly 55 tional, indefinite comminution of ñocs in the sep arate' sampling pipes. It is preferable to use~the in connection with the air lift, promotes flotation of relatively light particles, and such particles are combined now passage and sampling pipe 5l, ei readily released in the peripheral channel 25. ther alone or suitably alternating with the pipes 2li. ' Quiescent conditions are established in the top of this channel, by means of- radial varies 48, 60 Of course, all this is possible only if the skim.-v which may also support the large baille âfl and ming device d5, d6 can be eliminated. In some parts mounted thereon. . cases it is preferable -to have that skimming de In the modification of Fig. 4, the large periph vice, and in others, to provide the sampling iiow passages. " eral baille does not have to extend downwardly to points 2l below the discharge openings Sil, as 65 Various other modiñcations will occur to per in the preferred embodiment. In this modiñca sons skilled in the art. I claim: tion the large baille 50 has only spaced lower portions 5l extending downwardly topoints be low said openings, while large windows 52, of l. In a liquid treatment tank, a bottom having a substantially nat circular top surface for the 70 considerable height are provided between said uniform accumulation of settled sludge; a side spaced portions 5l. This may be desirable, above all, in relatively deep tanks, and where a large area is not so readily provided. With this ar rangement, a relatively deep layer of liquid and wall upstanding from a peripheral part of said. bottom; an annular baille downwardly extending - in the tank to define a channel outside said baille and a clarification chamber inside the same, said baiiie being so located that said channel has con anneau . d Vsiderably less area than said chamber, and said baffle terminating above said bottom so that the lower part of said channel communicates with the lower part of said chamber; flow collector 5. Apparatus according to claim 3, wherein said means to circulate liquid is supported by said column.V g 6. In a liquid treatment tank, a bottom; a side wall upstanding from a peripheral part of said bottom; -a substantially cylindrical baiile concen means in the tank, having an inlet in a lower, central portion of said chamber and comprising centrally located, annular wall means in the tank; trically installed in the tank to define a channel outside said baille 'and a clarification chamber inside the same, said baiile being so located that said channel has considerably less area than said chamber, 'and said baffle terminating above said bottom so that the lower part of said- channel communicates with the lower'part of said cham ber; flow collector means in the tank, having an inlet in a lower, central portion of said chamber , a set of ñow passages extending below said sur face, communicating with and outwardly radiat f ing from said now collector means, and also com municating with said’ channel by means of dis charge openings distributed along said channel, the total flow areaof said flow passages being considerably less' than that of said -channel; means to circulate liquid from said clarification chamber into said flow collector means, outwardly and comprising centrally located, annular wall means in the tank; a set of ñow passages extend through said dow passages, through said channel, ing through said bottom, communicating with and outwardly radiating vfrom said flow collector means, and also communicating with said chan-> nel by means of discharge openings distributed Ainwardly over said surface, and back into said flow collector means; means to deliver liquid to be treated and. any chemical reagents required into the circulating liquid; outlet means for along said channel, the total flow area of said dow passages being considerably less thanl that of said channel; means to circulate liquid from said sembly rotatably disposed over said surface to clariñcation chamber into- said ilow collector scrape sludge into said sump; and meansto rotate ' 25 means, outwardly through said iiow passages, said assembly. through said channel, inwardly-over said bottom, 2. Apparatus according to claim Ai., wherein said and back into said now collector means; means means to rotate said sludge scraper assembly , to deliver liquid to be treated and any chemical comprises a movable traction drive means se cured to an outer part of said scraper assembly 30 reagents required into the circulating liquid; out let means for treated liquid in the top of said and having driving engagement with stationary chamber; and sludge outlet means in a lower means adjacent the top of the tank. part of said tank. ' 3. In a liquid treatment tank, a bottom having '7. Apparatus according to claim 6 wherein said a. substantially hat circular surface for the 4uni ‘formy accumulation of settled sludge; a side wall 35 discharge openings are located in said wall, op treated liquid in the top of said chamber; a sludge outlet sump in said bottom; a sludgescraper as upstanding from a peripheral part of said bot tom; an annular baño downwardly extending in the tank to denne a channel outside said bañle and a, clarification chamber inside the same, said bañle terminating above said bottom so that the lower part of said channel communicates with ` the lower partof said chamber; a column extend-A posite said bañle. ' \ ' .58. Apparatus according to claim 6 wherein said discharge openings discharge in directions at least comprising inward components. 9. Apparatus according to claim 6 wherein said discharge openings discharge' in directions at least comprising upward components. 10. Apparatus according to claim 6 wherein said discharge openings discharge in directions comprising at least components tangential of said of the bottom below it being hollow; a drum con 45 centrically surrounding said column, extending 11. In a liquid treatment tank, a bottom; a side from the top of the tank to above but relatively . wall upstanding from a peripheral part of said adjacent said bottom, and so arranged that the bottom; an annular baffle downwardly extending space within the drum communicates with the. inside of said hollow column, whereby said drum 50 in the tank to define a channel outside said baille a clarlñcation chamber inside thesame, said and column provide a flow collector having an - and baille being so arranged that said channel has an inlet in a lower, central portion of said chamber; open top, and said baille terminating above said , a set of flow passages extendingl through said bottom so that the lower part of said channel bottom, communicating with and outwardly radiating from an inner, lower partof said flow 55 communicates with the lower part of said ber; flow collector means in the tank, having an collector, and also communicating with _ said inlet in a lower, central portion of said chamber channel by means of discharge openings dis and comprising centrally located, annular wall tributed along said channel, the total :dow-area means in the tank; a set of ñow passages, com of said flow passages being considerably less than municating with and outwardly radiating from that of said channel; means to deliver liquid to 60 said flow collector means,v and also communicat _be treated and any chemical reagents required ing with said channel by means of discharge into said ilow collector; means to circulate liquid openings distributed along said channel between from said clar‘iñcation cha’mber into said flow the top and bottom of the tank, the total flow area collector, outwardly through said flow passages, through said channel, inwardly 'over said surface, 65 of said flow passages being- considerably less than , that of said channel; means to circulate liquid and lback into said ñow collector; outlet means from said clarification chamber into said flow for treated liquid in the top of said chamber; a collector means, outwardly through lsaid now sludge outlet sump in said bottom; a sludge passages, through said channel, inwardly over scraper assembly rotatably disposed ov'èr said said flow collector surface to scrape sludge into said sump; and 70 said bottom, and back- into ‘ means; means to deliver liquid to be treated and means to rotate Isaid assembly. any chemical reagents required into the -circu 4. Apparatus according Íto claim 3, wherein lating liquid; outlet means for treated liquid in said drum, concentrically surrounding said:l col the top. of said chamber; sludge outlet means in umn, is rotatably supported thereby, and forms 75 slower part of said chamber; a substantially sta ing‘upwardly from said bottom in the center of the tank, said column- and the central portion baille. part of said sludge scraper assembly. ~ ' ' ‘ aaneen tionary scum trough in the top o? said channel; a movable scum blade associated with said trough; power means .to move said blade along the top of said channel; and an outlet for said trough. v 12. Apparatus according to claim 11 compris ing a stationary scum shelf associated with said trough, said shelfA and troughV spanning the top i3. Apparatus according to claim il compris1 ~ ing battles extending between said side wail and said annular baille, through a part of said chan' nel above said discharge openings but below the top of the tank, whereby the upper-part of said channel forms a quiescent scum release zone. while' the lower part of said channel» forms an agitated ñoccniation zone.; » of said channel, and said power means being adapted to move said blade along 'the top of said l0 _ FRANK D. PRAGER. channel, up said shelf, and over said trough.