Dec. 3,

I

p__ M THAYER

Re. 21,652.

METHOD AND APPARATUS FOR FILTERING ‘SEWAGE

Original Filed May 27, 1936‘

2 Sheets-Sheet. 1 A

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INVENTOR.

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ATTORNEY.

DH:- 3, 1940‘

P. M. THAYER I '

Rs. 21,652

METHOD AND APPARATUS FOR FILTERING SEWAqm

Original Filed May 27? 1956

2 Sheets-Sheet 2

Re. 21,652

Reissues! Dec. 3, 194i)

I UNITED STATES PATENT“ OFFICE METHOD AND APPARATUS FOR. FILTERING ‘

SEWAGE

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‘Paul M. Thayer, Milwaukee, Wis. Original No. 2,065,836, dated December 29, 1936, serial No. 81,977, May 27, 1936. Application for reissue December 24, 1938, Serial No. 247,722 11 Claims. (Cl. 210-44) This invention relates to a method and appa-_ ume stream of clear liquid, con?ning the clean ratus for ?ltering sewage. ing action to a limited progressing zone-ofv the Though the invention is not con?ned to a ?ltering means, and con?ning the disturbance continuous process or an apparatus for continu and agitation oi the sewage below the ?ltering 5 ous ?ltering of sewage, it is nevertheless emi means to a very small area far remote from nently adapted for such operation, and an ob the sedimentation zone so that the settling ac ject of this invention, therefore, is to provide a ' tion of the sewage is notin the least interfered method and an apparatus for the continuous with and so that the normal operation of the ?ltration of sewage.

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apparatus is undisturbed, thereby permitting

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In ?ltering sewage various means have been employed, such as providing a settling tank and ?ltering means through which the sewage passes,

and attempts have been made to clean the ?l tering means'while the apparatus is in opera 15 tion, but these attempts‘ have not proven wholly

satisfactory for several reasons, among which may be mentioned ‘the fact that during this

cleaning operation a considerable quantity of ,dirty liquid passes into the clear liquid stream 20 and also a large percent of the ?ltering material is lost and the device rendered less effective as I its time of use increases.

Also di?lculty has been experienced due to the fact that a very large amount of power is 25 consumed in these cleaning operations in cer

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In greater detail, objects of this invention are to provide a sewage ?ltering apparatus in which a settling tank is provided with a sedimentation

zone in the lower portion thereof, in which ?l

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tering means are ‘(provided at a convenient point

in the tank, for instance adjacent the margin or margins thereof, in which by means of a dif ferential level or pressure the sewage passes up

.wardl-y through the ?ltering means, in which .20 even the very ?ne solid material, such as the

colloidal material, may ,adhere to the under side of the ?ltering means and may form clusters or groups or aggregates whose mass is constant

tain forms of the heretofore known types of

ly augmented by oncoming, minute or colloidal 25 solids until ?nally these clusters either break

sewage ?lter cleaning means.

away and drop of their own weight or are dis

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' Further objects of this invention are to pro

vide an apparatus for ?ltering sewage which

3 O overcomes the above noted defects, which is so

made that it will continuously ?lter the sewage and also, if desired, continuously clean the ?lter ing means without causing the dirty liquid to ?ow outwardly with the clear liquid but con?n 35

the continuous operation of the machine while 10 the cleaning action is taking place.

ing the dirty liquid to the settling tank and pre venting its outward ?ow with the clear liquid, and in which the cleaning action may be inter mittent if desired or may go on continuously

lodged by the cleanlng means and settle to the bottom of the tank without getting the oppor tunity, even during cleaning, of passing upward ly through the ?ltering means, and to' provide 1 a cleaning apparatus which utilizes only the clear liquid above the ?ltering means and passes this clear liquid down at a low velocity and high volume.

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Further objects are to provide a cleaning de vice ter a sewage ?lter which is adapted to trav

eration to a restricted area thereof, leaving the

el continuously along and .above the ?ltering means, which draws clear liquid from above the ?ltering means and discharges it downwardly, 40 preferably entraining a large volume of other clear liquid so that a low velocity high volume

major portion of the ?ltering means undisturbed and active for the continuous operation of the

stream of ‘liquid is passed downwardly through the ?ltering means, thereby dislodging adhering

and may take place progressively, that is to say, 40 the cleaning means may progress along the ?l '- tering means and may con?ne its zone of op

45 ?ltering apparatus.

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A particular object of this invention is to pro

solids from the under side of the ?ltering 45 means.

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vide a. novel apparatus and a novel method of

Further objects are to provide a cleaning de sewagev ?ltration which contemplates the pro- , vice ter a sewage ?lter in which the ?ltering vision of a settling tank with a settling zone at means, if desired, maybe made su?lciently ?ex 50 a pointlremote from the ?ltering means; the ible so that it is slightly bowed downwardly or

sewage rising upwardly through the ?ltering

means and passing o? therefrom as a clear liq-_ uid, and at the same time to provide for the

progressive cleaning of the ?ltering means by 55 causing a down ?ow of a'low velocity high vol

manipulated during the cleaning operation and by the downwardly ?owing large volume of clear) liquid, thus assisting in dislodging adhering ma-' terials and removing any materials that may be held in the interstices of the ?ltering means.

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Further objects are to provide a novel form

suitable means, for example the motor 23, see Figure l, and suitable reduction mechanism may be provided for driving the sludge scraper.

ofcleaningmeansforthe?lteringmeansofa sewage?lter whichissomadethatitisself propelled or power driven and is power operated

The settling tank‘ provides a large, quiet area ‘

toskimordrawclearliquidfromtheupper portion of the clear liquid above the ?ltering - means and pump or force it downwardly with .

_ a relatively low velocity and high volume through

the ?ltering means, and in which the apparatus

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issomadethatthedischargemaybe adjusted

‘bothastovelocltyandvolume.

Further objects are to provide a ?ltering ap paratus for sewage which may be made very

cheaply, in- which the parts which are likely 15 to become worn during use may be cheaply and

readily replaced, andin which the initial instal lation may be made at a comparatively small cost.

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Embodiments of the invention are shown in 20 the accompanying drawings, in which: Figure 1 is a fragmentary vertical sectional

view of a sewage ?ltering apparatus. Figure 2 is a fragmentary plan‘ view of a por .

Figure 3 is a vertical elevation, partly in sec tion and with parts broken away, showing the

cleaning device, such view correspondingoto a ‘section on the line 3-3 of Figure 2. Figure tie a sectional view on the line H of Figure 3.

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charge channel 8.

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Figure 5, shows a modified form of the device.

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It has been found that even if the suspended 15 material is of colloidal form, that it will adhere to the screen or ?ltering means and will form clusters or aggregates of gradually increasing size which will, either by their own weight or from the cleaning means hereinafter described, ' dislodge and fall from the under side of the ?l tering means and settle to the bottom of the tank

tion of the ?ltering means, with parts broken away, showing the cleaning apparatus in posi tion.

for the gradual settling of the solid material downwardly from the sewage. However, there is a quantity of solid material that is suspended in the liquid and as the liquid passes upwardly, this suspended solid material, even if of colloidal form, is arrested or clings to the lower side of the ?lter 10 ing means l4 and the clari?ed or clear liquid ?ows upwardly through the ?ltering means and over?ows into the clear liquid launder or dis-,

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In order to prevent clogging of the ?ltering means and to provide for the ready cleaning thereof and the continuous uninterrupted oper ation of the sewage ?lter, a novel form of clean ing means has been, provided which is so made

that it does‘ not cause agitation in'the sedimen tation zone, but in which the washing or cleaning 80 of the ?ltering means is con?ned to‘ a very small

section or none closely adjacent the ?ltering means and extends downwardly beyond the ?lter

Referring to the drawings, it will be seen that - ing means only a very limited distance, the sedi a settling tank I has been provided which may be mentation none being remote or spaced a great

‘formed in any desired shape, for example cir cular, and may be provided with concrete side walls 2 and a concrete bottom I. The incoming sewage may be delivered through an inlet pipe 40 or pipes 74 which has an upwardly turned end I

distance?downwardly therefrom so that there is no interference in the settling out of the solid material during the cleaning or washing of the ?ltering means. The washing device may include a framework

de?ned ,by an annular downwardly extending baiiie "I. A clear liquid launder 8 may receive the

other structural member 24 provided with inner

discharged clear liquid and a suitable pipe or pipes I may be provided for carrying off the clear

portions are equipped with pairs of rollers ll

fordischargingthesewageintoastillingwellt

and outer end portions 25 and 20.

liquid receiving channel may be formed between

3'‘. Power means, such as an electric motor ii, is provided and is conveniently carried on ‘the outer member I" and belted to one of the outer wheels 28 so "as to propel the cleaning device

an upstanding outer wall ll of the main concrete side walls and an inner weir or over?ow bailie H

which may be formed, if desired, of sheet metal. An annular wall I! may be provided and may also be formed of sheet metal and preferably ex-v tends downwardly to a point below the lower edge of the stilling well wall ‘I, as shown in Figure 1.

around the tank-

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This ?ltering means is carriedin any suitable way, ‘as for example, upon the annular angle irons ' I5 and II. Additional stiffness for the structure > may be afforded by providing transverse struts l1,seeFlgure2,atregular-interva1s.

extends downwardly into a skimming member or I

and is preferably formed of removable-‘sections.

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Thelowerportimiofthesettlingtank I con stitutes a sedimentation none and preferably the

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A box like header I2, see Figure 3, is provided and receivesthe clear liquid from the discharge side of a rotary pump '33 whose intake pipe 34

Suitable brackets I! may be provided atintervals The ?ltering means is indicated at It ‘and may be a cloth or wire ‘screen, as shown in Figure '2,

These end, .

and ilksee Figures 1 and 2, which respectively ride upon inner and outer annular tracks I! and

?ltered liquid. ' The clear liquid launder I or clear

to support the member l2.

or body portion formed‘ of a central I-beam or

~scoop 35.

If desired, the scoop or skimming -_

member 35,, which is of rectangular boxlike shape, may be supported from the intake pipe 34 of the pump 38. An electric motor Il may be directly

coupled to the‘pump, as indicated in Figure 3, and the motor, pump and header 3! may be sup

ported from‘ the travelling carriage structure. The lower portionof the header I2 is only-par - tially closed by means of thebottom plate 31, a

slot I. being provided between a marginal edge of the channellike bottom plate 31 and the adja

bottom 3 thereof is slanted inwardly to. a centrally , cent wall of the’ header 3:.

This bottom plate -

located ‘sump II. If desired, a power driven 31 in reality constimtes a spreader plate to secure scraper consisting of a spider frame II with a uniform ?ow of the liquid downwardly through 70 scrapers 20 may be carried in any suitable man- the nozzle portion SI of the device, a baille ll be 70 ner,~as from a centrally located shaft 2!, and is ,ing preferably provided within the header to as designed tov scrape the sediment‘ or sludge at the in‘ securing a distributed and uniformv?ow ,bottomofthetankandcauseittograduallypass sist of liquid downwardly from the header. into the sump it, from which it is withdrawn or The nomle portion I! is formed by extending discharged by means of the sludge pipe 22. Any the inner wall 4| of the header downwardly and 7|

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by extending the outer wall 42 thereof down

or have found its way into the interstices of the

wardly and preferably on a slant towards the in

screen.

ner wall 4|. In forming the device, it is prefer able to make the wall 42 of lighter material. than 5 the wall 4| so that it may be ?exed to increase or decrease the size or width of the nozzle 33. The nozzle 39 supports‘ a forward and a rear

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The electric motors 3| and 36, see Figure 1, may be supplied with. current from rails 48, as shown, or any other suitable means to provide '5 power for the motors carried on the travelling cleaning device.

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plate 43 and 44 and these plates, as well as the nozzle, extend transversely across the ?ltering means, as shown most clearly in Figures 1, 2 and 3. Any suitable means may be provided for ad justably holding the nozzle and the plates. For example, a plurality of bolts 45 may be positioned

It will be seen that there is no possibility of the discharge of un?ltered sewage along with the clear liquid during the washing operation and 10 it will be seen further that the washing oper

at regular intervals and passed through: iitlre

Obviously the invention is not confined to a

15 nozzle and the plates 43 and 44. Spacers 46 are provided between the plate 43 and the wall 4| and spacers 41 are provided between the plate 44 and the lower or nozzle portion of the wall 42. Nuts are carried by the bolts 45, as vshown, and bear against the plates 43 and 44 and the walls 4| and 42.

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It is obvious that the opening or width of the slot of the nozzle 39 may be varied by backing the nuts bearing against the wall 42 and the plate 25 44 outwardly to increase the size of the nozzle, or moving them inwardly to decrease the size of the nozzle. Also the size of the spacers 41 or the size of both the groups of spacers 45 and 41 may be varied to vary the ‘spacing of the plates 4-3 and 44 from the nozzle.

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It will be observed from an examination 0

ation may be either continuous or intermittent as desired.

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circular tank, butmay be employed where the 15 settling tank is of rectangular or other shapes.v For example, as indicated in Figure 5, a rec

tangular tank 49 may be provided, the ?ltering section being indicated at 50 and the clear liquid launder at ii, the inlet and outlet pipes beinglin dicated at 62 and 53. The washing device is’ not shown in this view, but is adapted to travel back and forth over the ?ltering zone 50, as is

apparent from the preceding description. It will be seen that a novel sewage ?ltering ap

paratus and‘ a novel method of ?ltering and cleaning has been provided by this invention whereby a continuous operation of the ?ltering apparatus may be had and at the 'same time either continuous or intermittent cleaning of the 80 ?ltering means or screen may be secured by a

Figure 3, that the nozzle and plates 43 and 44' powerdriven automatic cleaning apparatus with constitute an injectorso that the downwardly ‘out in any way disturbing the gradual settling of the'solid material normally taking place in projected stream of liquid from the. nozzle en trains a large volume of liquid between the plates

the settling tank of the ?lter.

43 and 44 and projects this large volume low velocity stream of liquid downwardly against and

constructed very cheaply and that a very inex

It will be seen further that the device may be '

through‘ the ?ltering means or screen l4, thus . pensive ?ltering means maybe used, either cloth

cleaning the screen and dislodging adhering ma 40 terial from the screen.

As indicated by the ar- ‘

rows in Figure 3, the disturbance or agitation is con?ned to a very limited or restricted area im

mediately adjacent and below the screen and this disturbed area is far remote from the sedimen ‘45 tationzone and is con?ned at any instant to a limited area of the ?ltering means or screen.

Consequently there is no interference whatso ever to the free and undisturbed settling of solid material or to the continuous operation of the “0 ?lter as by far the major portion of the screen section is wholly clear and free of the cleaning device.

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As the cleaning device progresses forwardly in 65 the direction of the arrow, see Figure 3, the clear

or wire screen, or any other suitable material, and that means are provided which preclude the 40 clogging of the ?ltering means. It will be seen further that the initial cost of the ?ltering apparatus is relatively small and that the ‘cost of operation of the cleaning device is negligible as two relatively small motors are all that is required to operate the cleaning ap 45 paratus for the ?ltering means. Consequently, the consumption of power is extremely small for

the cleaning operation. Although this ‘invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed. I claim:

1. A ?ltering device having a main settling skimmer 35 from adjacent the top surface of chamber and having an over?ow weir and hav ing a zone of ?ltering material suspended hori the clear liquid, the liquid level above the ?lter ing means being indicated in Figure 3, and the zontally within the settling chamber adjacent 00 low velocity large volume stream of clear liquid ‘the weir and through which the liquid ‘to be is projected downwardly through the screen. ?ltered is adapted to pass in an upward direc The device progresses forwardly continuously tion. washing means movable along the ?ltering around the ?lter and thereby continuously cleans material and including power means for forcing liquid through the ?ltering material in the re the screen without interfering with they continu verse direction ‘from that normally travelled by 65 ous operation of the sewage ?lter. . It is to be noted, as indicated in Figure 3, that said liquid, said washing. means operating on the screen may be su?iciently ?exible so that it successive sections of‘ the ?ltering material and will be slightly bowed or distorted downwardly, allowing continuous and uninterrupted opera as shown in dotted lines in, such ?gure, while it tion of the ?ltering device, the solid removed 70 is- acted upon by the low~velocity large volume material dislodged from the bottom of the stream of clear liquid and consequently this ?ltering material falling back into the settling liquid is scooped up or drawn into the scoop or

working or motion of the screen while the clear

liquid'is passing through the bowed section will-_ assist in dislodging any adhering material that * may either cling to the under side of the screen

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‘ chamber.

, 2. A ?ltering device having a main settling, chamber and having an overflow weir and hav ing a zone of ?ltering material located horizon- 75

withinthesettlingchamberadjacenttho

andthroughwhich

and allowing continuous and uninterrupted op eration of the ?ltering device, whereby any agi tation on the inner side of 'the?ltering material is con?ned to asrnall zone located closely ad

jacent the inner side of the ?ltering material,_ the solid removed material dislodged from the ?ltering material passing immediately from the small agitated zone into an extensive quiet zone.

6.Awashingmeansi’orwashingthe?ltering

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?ltering device, the solid removed material dis~ lodged from the bottom of'the ?ltering material falling back into the settling chamber. 3. A ?ltering device having a main settling

material of a ?lter while said ?lter is inopera tion,‘ said washing means “comprising power driven means for ‘drawing clear liquid from one side of the ?ltering material and for forcing

clear liquid throughv thes?ltering material to wards the other side of the ?ltering material, said washing means having a discharge portion chamber and having a zone of ?ltering material A located adjacent the ?ltering material and hav suspended horizontally within the settling cham ing an injector carried adjacent thedischarge ber and through which the liquid to be ?ltered portion of the washing means, said injector hav is adapted to pass in an upward direction, means ing an intake for clear liquid located at a point 20 for temporarily collecting clear liquid after it - spaced from the ?ltering material. has passed upwardly through the ?ltering ma 7. A washing means for washing the ?ltering terial, washing means movable along the ?lter material of a ?lter while said ?lter'is in opera ingmaterial and including power means having tion, said washing means comprising power an intake for the clear liquid, said washing driven means for drawing clear liquid from one 25' means forcing the clear liquid through the ?l side of the ?ltering material and for forcing tering material in the reverse direction from clear liquid through the ?ltering material to that normally travelled by said liquid, said wash wards the other side of the ?ltering material, ing means operating on successive sections of > said washing‘ means having a discharge portion the ?ltering material, the solid removed mate located adjacent the ?ltering material and hav rial dislodged from the bottom of the ?ltering . ing an ‘injector carried adjacent the discharge 30 rnaterial‘falling back into the settling chamber. portion of the washing means, said injector hav-v 4.A?ltering devicehavingamain settling‘ ing an intake for clear liquid located at a point chamber and having an over?ow weir and hav-_ spaced from the ?ltering material and having ' ing a zone of ?ltering material suspended hori an intake for entraining liquid, said injector 35 zontally within the settling chamber adjacent having an adjustable member to vary the intake the over?ow weir and vthrough which the liquid opening for the entrained liquid.

tobe?lteredisadaptedtopassinanupward direction, washing means located above’ and 4° movable along the ?ltering material and includ ing power means for drawing clear liquid from above the ?ltering material and for forcing the said clear liquid downwardly through the ?lter ing material, said washing means including 45 means for entraining additional 'clear liquid from above the ?ltering material adjacent the discharge portion of said washing means to pro duce a large volume low velocity downwardly projected stream of clear liquid. through said 50 ?ltering material, said washing ‘means operat

ing on successive sections of the ?ltering mate-.

rial and allowing continuous and uninterrupted operation of the ?ltering device, whereby any agitation below the ?ltering material is con?ned : 55 to a shallow zone located closely adjacent the

lower side of the ?ltering material, the solid re . moved material dislodged from the bottom of

. 8. Washing means for a ?lter having extended ?ltering means, said washing means comprising '

power driven means for drawing clear liquid from one side of said ?ltering means and for

forcing clear" liquid through ‘the ?ltering means to the other side thereof, said washing means having the intake portion thereof provided with a skimmer having an open portion directed away

from the ?ltering means and having a discharge

portion located adjacent. the ?ltering means, and an injector located adjacent the discharge portion of said washing means for entraining

aditional clear liquid, said injector having its inlet portion located at a point spaced from said ?ltering means.

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9. The method of continuously ?ltering sew age comprising passing sewage upwardly through a ?ltering means, allowing the solid material in 55 the sewage to settle at a material distance below

the ?ltering material falling back intorthe set-" the point of ?ltration, discharging the clari?ed

liquid from the upper side of the ?ltering means ' ' 5. a ?ltering device having r‘ main settling _ and progressively operating on successive sec tions of the ?ltering means by passing a low chamber and having an over?ow weir- and hav velocity relatively high volume ?ow of the ?l ing a zone of ?ltering material suspended with vtered liquid downwardly through the ?ltering in the settling chamber adjacent the over?ow means to dislodge adhering material from the weir and through which the liquid to be ?ltered imder side of the ?ltering means without causing 65 is adapted to pass to said over?ow weir, wash agitation of the sedimentation. ing means movable along the ?ltering material 10.'A ?ltering device having a main settling and including power means for drawing clear chamber and having an over?ow weir and hav liquid from the over?ow side of the ?ltering ma ing a zone of ?ltering material suspended within ' ter'ial and for forcing the said clear liquid through the settling chamber adjacent the over?ow weir the ?ltering material in the reverse direction to and'through which: the liquid to be ?ltered is the normal ?ow through the ?ltering material, adapted to pass to said over?ow weir, washing said washing means producing a large volume means movable along the ?ltering material and . , low velocity stream of clear liquid through said including power means for drawing clear liquid ?ltering material, said washing means operating from the over?ow side of ‘the ?ltering material onsuccessive sectionsottho?ltsringinaterisl and for causing a part of the said clear liquid tling chamber.

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ll. 'lhe method of continuously ?ltering sew to ?ow through the ?ltering material in the re age comprising passing sewage through a ?lter verse direction to the normal ?ow through the ?ltering material, said washing means producing > ing means, allowing the solidmaterial in the to settle at a distance from the point of a large volume low velocity stream‘of clear liquid ' sewage through said ?ltering " material, said washing ?ltration; discharging the clari?ed liquid from one side ‘of the ?ltering means and progresively means operating on successive sections 01 the, ?ltering material and“ allowing continuous and operating on‘ successive sections of the ?ltering uninterrupted operation of the ?ltering device. means by passing a low velocity high volume ?ow whereby any agitation on the inner side of the oi the ?ltered liquid backwardly through the ?l 10 tering means to dislodge adhering material from lo ?ltering material is con?ned to a small zone lo the slide of the ?ltering means which is normally lated closely adjacent the inner side of the ?lter upstream without causing agitation of the sedi ing material, the solid removed material dis mentation and by conducting the dislodged sedi lodged irom the ?ltering material passing im mediately irom the'small agitated zone into an mentation to the settlement area without agita tion su?lcient to break up the ?ocks oi sedimen 16 extensive quiet gone without the velocity of ?ow tation as removed irom the ?ltering means. or the removed solid material being increased be yond that at which it was removed from the ?l ‘PAUL Ni. THAY'ER. “ tering material. ,1

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