US2585006A - Sedimentation unit - Google Patents

Description

Feb. 12, 1952 GRANER ETAL 2,585,006

SEDIMENTATION UNIT Filed Jan. 29, 1947 4 Sheets-Sheet l INVENTORS FRANK L GRANER e.

cumgzs HAROLD SCOTT,

ATTORNEY Feb. 12, 1952 F. 1.. GRANER ETAL SEDIMENTATION UNIT 4 Sheets-Sheet 2 Filed Jan. 29, 1947 INVENTORS :FRANK L.GRANER a CHAQIIES HAROLD SCOTT, GM mm ATTORN EY Feb. 12, 1952 Filed Jan. 29, 1947 F. L. GRANER ETAL SEDIMENTATION UNIT 4 Sheets-Sheet! 5 FIG. 5.

INVENTORS FRANK L.GRANER 8 CHABRYLES HAROLD SCOTT, MW

ATTORNEY Feb. 12, 1952 F. VGRANER ET AL SEDIMENTATION UNIT 4 Sheets-Sheet 4 Filed Jan. 29. 1947 CHARLES HAROLD SCOTT,

' ATTORNEY Patented Feb. 1 2, 1952 Harold' Scott,- Westport, Conn}, assignorsto The Don: Company, New York, N. Y.,' a: corporation.

of Delaware Application January 29, 1947,. Serial No. 725,086

This invention relates to sedimentationunits; or thickeners as such units are sometimestermed, having motivated sedimented-collecting 'or sedi ment-impelling mechanism operable in a tankorbasin over a floor or bottom section thereof, and the invention particularly relates to meansadapt able for safeguarding the unit and the mechanismthereof against damage upon or consequent to abnormal overload conditions beingencountered by or imposed on the sediment-engaging elements of said mechanism.

An object of the present invention is to provide novel apparatus or arrangement of parts or operative elements certain of which embody novel features of construction and operation whereby there is realized as a complete and effectively efficient organization a practical and reliable embodiment of operatively associated means that readily respond to the operative requirements for simple startingupof the apparatus, and also for continued normal operations, including an automatic raising of the sediment-engaging members according to substantial" increasesabove maximum normal load conditions being encountered and a progressive lowering of the sediment engaging members as the load condition reaches and decreases below the maximum normal therefor. The novel apparatus functions toarrest all operative movements of the sediment-engaging members or impelling elements and the driving mechanism therefor when an abnormal overloadcondition is substantially greater than that of the maximum normal has been encountered; such arrestingof operation may be selectively determined and has in view the stoppingor arresting of the movements of the sediment-impelling mechanism before damaging forces on the unit or parts thereof have been or are'likely' to be encountered. Y

Many novel features of construction are embodied in the sedimentation unit and particu-- larly in connection with the power actua-tedor" thereof, will be understoodffrom thefollowing description of a specific embodiment when read" 1 2 Claims.. (01. 210-55) 2 or considered in connection with theaccompanying drawings constituting a part of this specification and in which:

Fig. l is a vertical viewpartly in section and with portions thereof broken aw-ayof a typical tank or settling basis equipped with sediment-raking mechanism providing rake-carrying arms extending outwardly from a raisable lift shaft and in diverse positions ofelevation therefor tumable about a vertically-extending axial line through the medium of suitable" motivated mechanism.

Fig. 2 is a, view taken as on the line 2--2 of Fig. 1; looking in the direction of the arrow. This figure shows certain details of construction whereby turning movement for a rake arm is imparted thereto from power-transmission member of the'motivated mechanism.

Fig. 3 is a vertical view-partly in sectionshowing a mainor primary motor with speedreducing andpow'er-act'uated" means constituting part of the motivated mechanism for turning the rake arms. This view also-shows in assembly an'auxi'liary or pump motor and associated pump driven therein constituting part' of an automaticallycontrolled'hydraulic system embodying an expansible and contractible lifting means for effecting an automatic lifting of the rake-carrying arms as and when excessively heavy rake load-conditions are encountered by the rake-carrying arms; In this figure there is indicated an electrical control system that automatically controls the starting and stopping of the pump and also'for use in arresting the operation of the main motor should operating loadthereof become sufiiciently excessive whereby the motor or a part driven thereby might otherwise be damaged or caused to fail.

Fig. 4' is a vertical sectional view of a by-pass valve construction employed in the hydraulic system just referred to. The location of the valve of Fig. 4 is readily ascertainable from an inspection of either Fig. 3" or Fig. 5. The parts are shown in Fig. 4 at larger scale than in either Fig.3or Fig. 5';

Fig. 5 is a vertical view-partially in section and of" which certain parts have been broken awayshowing in cooperativearrangement certain details of the rake-carrying arms the hydrauliclifting means by'which the rake-carrying arms are vertically positionable through the medium of'the lift shaft from the lower end of which the rake carrying arms extend and certain parts of the motivated mechanism by which said-rakecarryingarms are caused to turn about a verspect to a surrounding depending torque tube constituting part of the means by which power is transmitted to the rake-carrying arms for turning the same. In Fig. 6 the liftable or raisable piston is in low or contracted position therefor with respect to the cylinder. In Fig. 7. thepiston and parts carried therefrom are shown in an upper position therefor.

Reference will now be made to the drawings" in detail: 1

Therein a sedimentation tank or basin illustrated embodying a .flooror bottom portion II, a marginal wall l2 rising from said bottom portion, a marginal launder l3 for-receiving supernatant liquid overflow passing thereinto from the overflow weir or weir edge l4; an effluent outflow [5 leading from the verflowlaunder 13; a sludgeor sediment-receiving and discharge section provided by a sludge sump or cone at l6 served by a sump rake 26 and a discharge conduit I'I leading frornthe sump to a region outside of the unit. h I

Liquid to be treated for removal therefrom of settleable material is s pplied to the upper central portion of the tank through the medium of a feed-supply means terminating in a feed-distributing well [8 having apertured feed-discharge openings at l9. 7

Also associated with the tank andconstituting a part of the sedimentation unit as a whole is a frame structure 20, constituting a superjacent support, stationarily positioned with respect to the tank. This frame structure serves as a support for a portion of said supply means and feed-, well thereof, it also serves as a support fora motivated sediment-raking mechanism collectively designated and constituting the means by which settled solids on the tank bottom can be impelled towards and into a sediment-receiving sump provided in or by the bottom.

The sediment-raking mechanism collectively designated 25 embodies sub-sets of members or functioning mechanical elements which may be designated as follows:

1. Motivated power-transmission gearing 53 or main driving construction embodies a bull gear or wheel 52 constituting a main turntable which is turnable about a vertically-extending main axial line and which is mounted on a stationary bearing member 5| that derives carrying support from the I-beams 22 of the main frame structure 20. Anti-friction balls or rollers may be provided as at 56 between the supporting and supported members 5| and 52 of a main turntable construction 50 thus provided thereby.

2. An expansible and contractible lifting 40 embodying:

(a) A stationary lifting cylinder 46 of constant means elevation having a low cylinder head and cylinder wall rising therefrom, which cylinder 45 derives carrying support through the medium of a central depending carrying tube 43 con-v connection with the low head 45 of the lifting cylinder, and

(b) A liftable piston element having an annular piston head 6| slidably fitting the interior of the cylinder wall and the exterior of the depending tube and a hollow piston rod 62 rising from said annular piston head. At the upper end of this piston rod 62 there is carried a liftable base or supporting member 64 constituting part of an auxiliary turntable construction 63 of which the turnably supported member or auxiliary turntable is provided by an annular cap 61. The liftable base 64 has a raceway or supporting bearing 65 and the turntable cap 61 is provided with a raceway or supported bearing 68; anti-friction rollers or balls 66 are provided between said raceways. The expansible and contractible lifting means 40 as provided by the lifting cylinder 46 and liftable piston element 60 may be viewed as a plunger means having a supported member 46 and a liftable plunger 60 and a pressure liquid receiving space 48 within the plunger means between the supported member 46 and the plunger 60 just referred to.

3. A liftable vertically-positionable sedimentraking element 30 embodying a vertically-extending liftable arm-carrying shaft or lift tube 3| equipped with intermediate arm-carrying members collectively designated 32 extending from the lower portion of the lift tube, and a set of outwardly-extending rake-carrying arms 33 carried from said intermediate members 32. The lift tube or shaft 3| derives its liftable support from the auxiliary turntable 63 above referred to; and

4. Power-transmission mechanism collectively designated 10 and functioning between the bull wheel or main turntable 52 on the one hand and the rake-carrying arms 33 on the other hand. The power transmission mechanism 10 may be referred to as the bull wheel driven or motivated rake-arm turning mechanism. This mechanism embodies the torque tube H which is driven by and has depending carrying support from the bull wheel, an outwardly-extending frame structure generally designated I20 secured to and extending from the lower end 12 of the torque tube and hinged outwardly-extending power-transmission arms of which the inner ends have hinged connections at 13 to the outlying members of said outwardly-extending frame structure I20 while the outer or swinging ends of the power-transmission arms have suitable connections as by links to the corresponding portions of the underlying rake arms 33.

The frame structure 20 also serves as a support for a liquid-supply means provided as by an oil or liquid-supply tank I00, an associated pump [DI and an auxiliary motor PM which when the operating circuit therefor is closed actuates the pump. The pump is embodied in a hydraulic system and is connected through the medium of suitable piping so as to supply when actuated pumped oil or other liquid from said supply tank I00 to and through a central flow passageway 44 of the depending central tube 43 and so as to deliver the same under pressure through flow passageways 42 at the lower end of tube 43 into the stationary cylinder of the expansible and contractible means 40, to wit, in the region 48 above the cylinder head 45 but below the piston head 6!, whereby the pressure liquid thus supplied can effect a lifting of the piston as a movable element of the expansible and contractible lifting means and therebythe auxiliary turntable construction and the rake-carrying arms 'i which are mai rectly" carried from the" auxiliary turntable con-- struction through the medium of the-liftable arm-carrying shaft 31'.

It will also hereinafter'more fully-appear that permitting a progressive lowering of the lifttube 3i! and the rake-carrying arms after the-motor operating the pump has ceased to run.

The depending torque tube I! has an interior diameter substantially larger than that of the diameter of the exterior portion of the depending j arm-carrying shaft 3i. A flanged annular guidefl sleeve 69 at elevation higher than that of theoverflow weir edge !4 is provided-between'the' upper interior portion of the torque tube ll and the exterior of the arm-carrying or lift shaft 3!.,'

This guide is preferably of bronze and serves not only as a guiding member but also as ineans'for establishing and maintaining concentrioity as between the upper end of the torque tube and that portion of the lift shaft at that particular elevation.

By the power-transmission mechanism ll; just referred to there is realized means whereby a continued turning of the bull Wheel or gear 52 effects a horizontal turning of the raise arms'iiI-i as a set about a vertically-extending axis for each and all diverse positions of elevation thereof.

Reverting to the motivating power-transmission gearing 53, it will be noted from an inspection of Fig. 3 that a motor M may be provided with a housing physically connected to and car'- ried from a section of the casing structurefor the motivated gearing 53. Power from the rotor of the motor is transmitted to an initially driven gear of the motivated mechanism 53, as for example, through the medium of pulleysandbelts. 59 the latter of which are indicated, by dot-and;- dash lines. The thus motivated power-transmission gearing 53has gears or gear elements as" 54 drivingly engaging a peripheral gear 55-of the bull gear or wheel 52 as is indicated insaid Fig. 3.

Certain important aspects and features of the invention include anovel embodiment of a. plunger lifting means in a sediment-raking mechanism; and furthermore in the coordinated operative arrangement and relationship thereof with respect to other functioning parts or means of the apparatus or equipment provided'in or for a settling tank or basin or for use therein. That is to say, certain important aspects of themvention hereof revolve about (1) the construction; and arrangement of parts constituting-the expansible and contractible lifting-means 4|] that includes a lifting cylinder 46 having a. low. cylinf der head 45 with cylindrical wall rising therefrom a vertically-movable piston 60 embodying an annular head 6| with piston rod 62 rising; therefrom and having slidable fitting engagement Withthe interior of the cylindrical wall on the one hand. and the exterior of a depending center. support or cylinder carrying tube 43 on the other. hand; (2) the mode of support for the stationarily mounted lifting cylinder from an overlying por-- tion of. the frame structure through the medium: of, the aforementioned tube 43 the lower end or which is: fixedly connected to the cylinder head 45; whereby thereis provided: or left within; the. lifting, cylinder an. annular piston receiving Space rising from the cylinder head 45 and within It T which s a ee'urepiston heaesr-haevertieai ris ing and 'loweringmovementr (-35 to certain de tails of construction of the tubular support E3 and the associated cylinder head-and pistonhead whereby-fluid under pressure is deliverable into the tubular support and therefrom through pas sageway or flow'openings l2"=into the region 4% between the-- heads for imparting lifting move? ment to the-piston and whereby a lowering of" the piston'can follow because of" meansprovided in the hydraulic systemsifor allowing for-a bacl'rflow and controlled. release of-bleed'erliquidfrom thespaceflabetween the-heads through openings GZfi'ii'torthe central-flow pass'ageway" 4 4' of" the tirbe'and fronrthe upper endof'the latter when conditions-are right for lowering the piston; (47' thep'rcw'iding of a* turntable construction, 63" be tweenthe upper end of the'hollow piston 'rodand" the supporting cap or'auxi'liaryturntable Grimm or bywhi'ch there is turnably carried the "lift tube" 3t of the liftable raking assembly' 3'0"'wherebyas the piston 60' is elevated it can impart a litfting' movement to the lifttube 31 while at tire same' time permitting turning movement of'thelifttube" about the expansible and contractible" lifting-- means 40' as a'whole; (-5)" the arranging or posi tioning of the depending torque tube TI and of the bullwheel 52 at elevations'such that the bull gear and the upper endiofthe depending torque tube H which is connected thereto was to be turnably driven thereby are located at elevations whereat they surround the-upper portion of the lift tube 3|, or as otherwise expressed, in a-region surrounding but spaced from the vertically rais able and lowerable piston 60 ;v and. (6 theiproviding of a guide sleeve 69'betwe'en thebullwhe'el-53 and the connected upper end" of th'e'torque: tube TI on the one hand and the upper end of the lift' tube 3| on the other, which said guide sleeve serves not only as a guiding member but also as meansfor insuring concentricity' of themem-bers' just mentionedand'also as a stop membercarried by the bullwheel and'functioni'nga's a means for arresting and. limiting" the downward move ment of the lift tube; 3| and. thusl'y of. the rake carrying arms 33'extending' outwardly'as a set from. the lower'end portionlof the lift tube.

'Many of the important features of the con-=- struction just mentioned are apparent fromv aninspection of Figs. 6 and 7 hereof and thuslyit is in order to described certain parts thereof infurther detail; i

By Figs."6 and 7" there will be seen certain de--' tails of construction of the specific means by which the center support" or depending carrying tube 43 may derive or have carrying support? fromthe channel members 2| of the frame'supportingstructure 2E]; The means thus shown'em bodies a supporting block I08 resting directly upon the channel members 21:. Upon this sup port block I08 there is mounted a support block seat H39" having a concaved' upper seat surface H6 following the general contour of a sphere. A center tube yoke HI having. a lower portion extending therefrom provides a convex surface- I I2 that directly and fittingly engages-the concave face or seating surface Hi1 of the support block seat I09. The spherical seat constructionxjust mentioned is provided whereby a desired adjustment of] the vertical tube 43 can be readily realized,, to wit, so 'asto attain substantial align-'- ment with the vertical axis through the central portion thereof. Asupport tube nut I |3 thread-' ingly engagesthe; upper screw-threaded} portion ofth'tubefl and serves as a member-by which the weight of the center support tube 43 and parts carried therefrom. is transmittefto the center tube yoke I I I and tothe channel members 2I. Thefupper endofthe center support tube 43 which it will be noted is not turnable about an axial linehas securedthereto a pipeconnection I04 constituting'apartof the tubular piping with respect to the cylinder head through the medium'of a' set screw I'I5l' The lifting cylinder 46 which is herein described'as having a cylindrical wall rising from the head thereof has, as

made, a tubular wall portion I I6 the lower end of which has an annular flange I I1 that is weld connected thereto which is directly connected to a corresponding flange portion of the cylinder head through the medium of bolts H8 and whereby a water-tight joint is provided between the lower end of the cylinder wall and the cylinder head. An upper flange member H9 is weld connected to the upper end of the cylindric'al end or wall H6 and a piston rod guide I30 is connected by bolts I3I to the flange I I9. This pistonrod guide has an opening I32 provided therethrough for receiving the piston rod 62 heretofore referred to. An air passageway is provided at I33 whereby to permit an ingress or egress of air from the annular'or piston slide space I34 that is provided or left between the interior of the cylinder portion H6 and the exterior of the hollow piston rod 62. The piston rod 62 which has been described as rising from the piston head 6| has a screw-threadedconnection to the piston head BI and is locked into position through the medium of a set screw or the equivalent at I35. The piston rod has annular cup-leather packings at I36 and a series of annular packings of inverted V-shape cross-section arranged in superposed relationship'at I31. These packings referred to are held in place by an annular retaining ring I38 which'is secured in place at the lower face of the piston ,head' 6I through the medium of bolts at I39. As to the turnable construction 63 which is carried at the upper end of the piston rod 62, this is shown in considerably greater detail than in the other figures hereof.

In Figs. 6 and '7 it will be observed that the supporting member 64 heretofore referred to and described as being carried at the upper end of the hollow piston rod' 62 embodies a raceway bearing element 65 upon which the anti-friction balls or rollers 65 are directly supported. The lift tube cap 61 heretofore referred to as an annular cap or auxiliary turntable is provided with a turnably supported raceway member 68. The

cap or turntable 61 has a depending annular flange portion I46 to which there is secured through the medium of bolts I M a thrust end or underlying cap I42 equipped with an annular oil-sealing means I43 for retaining a quantity of lubricating liquid or oil in the region I44 whereat the ball bearing members 65, 66 and 68 are located. Means for introducing oil into the region H4 is provided at I45. A vent hole is provided at I46 in the cap or auxiliary turntable member 61.

v Theupper end of the lift tube 3I is provided witha flange ring [I48 which isweld connected 8 thereto andwhich is detachably connected through the medium of bolts I40 to the outer portion of the lifting tube cap 61.

Referring now to the guide sleeve 63 heretofore mentioned, it will be noted that this is secured in place through the medium of bolts I50 to the inner portion of the bull wheel or gear 52 and that it has sliding engagement with the exterior of the upper portion of the lift tube 3I whereby concentricity of arrangement as between the bull wheel 52 and the torque tube 1I connected thereto and carried therefrom on the one hand and the lift tube III on the other hand will be maintained and whereby indirectly the piston and cylinder of the lifting means 40 and the depending tubular support 43 by which the lifting means is carried will also be maintained in concentric relationship. It will also be noted that guide sleeve 69 also serves as a low-limit stop means for the lift tube 3| and parts carried thereby.

From that which has preceded, it will be manifest that the lifting means, the lift shaft which is raisable and lowerable thereby, and the actu ating means by which from the torque tube the rake arms and parts carrying the same are caused to turn, are embodied in a novel construction v realizable because of the novel arrangement of parts and members hertofore referred to.

The hydraulic means by which the expansible and contractible lifting means are caused to function is one which is preferably, but not necessarily under automatic control. No matter how controlled, viz. manually or automatically, it is important in realizing certain features of the invention to have a proper means for supplying liquid under pressure to the expansible and contractible means for imparting lifting movement to the rakes when overload conditions-surpassing those normally encounteredare experienced and for permitting the lowering of the rakes or rake-carrying mechanism after these overload conditions have been overcome. The hydraulic means heretofore mentioned and by which this is attained is shown in relatively complete detail in Figs. 3 and 5, however, an amplification of an important functioning part or relief valve thereof is shown at a larger scale in Fig. 4.

As previously mentioned, an oil supply tank or liquid-holding means is indicated as I00. In Fig. 5 the lower interior portion thereof is shown divided into three sections, to wit, I68, I69 and I10 by two partial partition members rising partway upwardly from the floor of the tank. This oil supply means has a pump motor PM physically connected for driving the pump IOI when the circuit for the motor is closed whereby to suck oil from the section I69 through a filter or strainer I1I into an intake or suction line I02 leading into the pump I0 I. From the pump IOI the pump discharges pressure liquid into a pressure delivery line generally designated I03 and leading to and terminating in the pipe connection I04 that in turn is connected to and in communication with the upper end of the depending tubular carrier 43. In this line I03 there is embodied a by-pass or relief valve I12, a back-flow check valve I13 and a pressure cage I14. The relief valve I12 is shown in section in Fig. 4 and is of a type well known in the art. This relief valve is constructed so that under ordinary or normally encountered operating pressures for the pump the flow from the pump is through a pipe section I15 of the pressure delivery line I03 directly past a dependportion I16 of apiston valve I11 into a pipe seas s section I18 leading to a check valve I13, the latter of which functions to allow 'a'free"forward flow of liquid entering the same on its way through pipe line I03 to 'pipeconnections I04. The check valve I13 as embodied inthe line I03 is provided to prevent anyback-flow, to wit, into the relief valve I12. This relief valve I12, however, is so constructed that if the pressure in the line I03 which includes the sections "I15 and I1 8 becomes unduly excessive there is a lifting of the piston valve I11 and consequent unseating of the depending valve section I16 from the seat or seat member I19 whereby there is permitted a bypass, shunt or split off flow of liquid from the line section I15 past the unseated depending portion I16 of the piston valve'into and through the seat I19 into pipe section I80 the latter of which delivers any thus by-passed liquid into the tank section I10. In this way there may be diverted all of the pumped 'liquid-or'only a portion of the pumped liquid from the line I15 into the tank section I thereby avoiding an undue supply of pressure liquid into and through the pipe I03 and correspondingly allowing the pump to be continuously operated well within the safe limits while the motor continues to run, oryas otherwise expressed, in a manner whereby to avoid undue overloading of the motor. Should the motor be stopped either by automatic control -or otherwise the check valve at I13 prevents back-flow of pressure liquid from within that section of the line I03-wh'ich-isphysicallylocated between the check valve I13 on the'one hand and the pipe coupling I04 on the other. A pressure gauge I14 is provided whereby an operator can ascertain and have visual information as to the exact pressure conditions Within the line 'I 03 and 'thusly within the expans'ible and contractible'li'fti-ng means 40.

Mention has heretofore been made of the "fact that when themotor is stopped andrthereby the pumping operation has beendiscontinued, as, for example, when raking overload conditions have been overcome that therercan follow :or should follow a progressive lowering of the lift tube '3I and of the rakes :carried thereby. This progressive lowering is attained by the release of what may be viewed as 'bleeder liquid, to wit, liquid which flows upwardly within and from the tube 43 to wit, from the space 58 between the piston head 6I and the cylinder head 45 any liquid released as bleeder liquid flows into .and from the .pipe fitting its and in sequence through the pipe section I95, which may be viewed as a return pipe section, into and through'the bleeder "valve Hi5, and finally from the terminal section 1:01 of that which-may be considered as :a return or bleeder pipe leading into the tank-receiving portion M8. in this connection it will be noted that the position of the valve element 106, to wit, the bleeder valve as it should-be called, can be adjusted for regulating the rateof backfiow of bleeder liquid from the progressively :contracted space between the piston :and cylinder heads towards and past the valve I06 andwhereby the released liquid is ultimately received back into the liquidholdin'g tank. The weight of the lift tube 3i and the parts carried thereby are sufficient to effect the lowering of the parts carried by the piston and the back-flow of the released or bleeder liquid until the rakingelements have assumed the normal low-raking posit-ion therefor. I h

At this juncture it will be-noted that a stop member 41 rising from the low-cylinder head 45"arrests the downward movement or determines the low-limit movement of the piston relative .to the head 45 and assures aliqu'id receiving space 48 into which presure liquid can at all 'times'be delivered from the interior of the tube 03 through the flow opening at the low end thereof.

Mention has heretofore been made that there is progressively employed 'an electrical control "system whereby when unduly excessive overload conditions are experienced by the motor this will automatically be stopped before the motor ping ofthe motor whereby the progressive lowering of the raking mechanism can be accomplished through the medium of the hydraulic system thus described. I

From what has preceded, it will be manifest that during the normal employment of thesedimentation unit for the purpose of 'efiecting the clarifying .of'the liquid bearing settleable solids that the supply of such liquid to the tank or basin is of more or less uniform rate that the motor M is continuously operating progressively collecting sedimented'materia'l from diverse portions of the floor of the tank towards the sediment sump "I6 that upon abnormally excessive raking overload conditions being encountered bythe sediment-raking mechanism the motor "is caused to actuate and thereby operating and supplying pumped liquid into the space between the lifting cylinder head and the liftable pump head of the piston thereby effecting a progressive lifting of the 'rake lifting imeans "while the latter is continued to be turned by the motor M through the "gearing and the medium of the bull wheel thereof the depending torque tube secured to and depending from the bull wheel and the power-transmission arms extending from the lower portion of the bull wheel and having a link connection to the rake "arms underlying the same whereby there is permitted the requisite lifting movement to the rake arm's while at the same time imparting horizontal turning movement thereto about a verticallyextending axis.

The motors M, PM are preferably but not necessarily embodied in an automatic system according to which operatingenergy-specifically electrical energy for operating motors is controllably supplied from a suitable source of electrical "energy supply generally designated SE through a control system generally designated CS from which there is a control supply of power through one'set of wiring to the motor M and through another-set of wiring, which maybe referred to as a branching energy-transmission means or line, leadingto the motor PM that actuates the pump 101 according to operative requirements. 'The branching line just referred to includes the wires 1 and e '(see Fig. 3') and an automatically positioned (control switch such as switch member actuated by magnetic coil B.

'In other words, according to the control system just referred to during the normal raking load operations the motor M is actuating the sediment-raking mechanism 25, to wit, in the general normal or low operating position for the rake-carrying arms 33 thereof. If, however, the raking load becomes abnormally excessive this control system CS comes into play, through the medium of the branching energy-transmission line, to start the operation of the motor PM for effecting of the delivery of pressure liquid, to wit, oil under pressure from the pump into the expansible and contractible lifting mechanism 40 for expanding the latter and thereby effecting an automatic lifting of the liftable element thereof and a consequent upward movement of the lift tube 3| from which the rake-carrying arms'33 extend. When the excessive rake load conditions have been overcome there is an automatic stopping of the motor PM and this is followed by a permissible lowering of the previously lifted rake-carrying arms 33 due to a progressive contracting of the expansible and contractible lifting means, which contracting is permitted to take place because of the progressive release of the oil or other liquid through and from the bleeder valve I06.

Also in the electrical control system CS provision is preferably made for automatic stopping of the motor M and thereby stopping of all turning movement of the raking mechanism should the load upon the latter become sufficiently excessive, to wit, to an extent whereby the motor M or other mechanism actuated therefrom might be otherwise damaged. Electric wiring from the control system CS to motor M is indicated as c and d while electric wiring from the control system CS to the. pump motor PM is indicated as In short, however, according to the control system just referred to during normal raking load operations the motor M functions through the medium of the belt-drive 59 and the motivated power-transmission gear 53 to effect a horizontal turnin of the depending torque tube H and therefrom to the underlying rake-carrying arms 33 through the medium of the hinged outwardlyextending power-transmission arms 80 of which the outer ends have link connections 90 whereby said arms 33 as a set have horizontal turning movement about the main vertically-extending axial line and whereby they are thus operable in any position of elevation therefor as well as at any and all times when being changed from one elevation to another.

. -Also during the time when the rake load sumciently exceeds a normal raking load but is not sufficiently excessive to damage the motor or parts actuated therefrom the motor M continues to operate and thus functions to effect the con tinued turning of the rake arms but under such abnormal overload conditions as those just stated, the control system CS is such as to cause the starting up operation of the pump motor PM and thusly the pump IUI whereby to send pressure liquid into the expansible and contractible lifting means 40 for effecting a raising of the rake-carryingarms 33 with a consequent lessening of the raking load. This upward movement of the raking arms continues until the abnormally excess ve overload conditions have been overcome at which time the control mechanism causes the pump motor to automatically stop and a p gressive lowering of the rake arms can follow. For supplyingliquid under pressure that is relied upon for expanding the expansible and QQII'ZIQC'T tible lifting means as provided by the piston and cylinder construction referred to herein, reliance is made upon a hydraulic system that includes a pump IOI actuated from the motor PM which when operating delivers liquid, to wit, oil under pressure, into the upper end of the depending carrying tube 43 and which hydraulic system is equipped with a valve-controlled bleeder line that functions to permit a gradual release of entrapped liquid in the system whereby to permit a contracting of the expansible and contractible lifting means, or as otherwise expressed, a progressive lowering of the piston after the motor has ceased to actuate the pump. This hydraulic system will hereinafter be described in detail.

. The main motor M and the pump motor PM just referred to are preferably, but not necessarily embodied in an automatic system according to which electrical energy for operating the motors is controllably supplied from a suitable source of electrical energy generally designated SE through a control system generally designated CS from which there is a control supply of power through one set of wiring to the motor PM that actuates the pump IUI according to operative requirements, etc.

As to the supply means' 00 and pump IOI, it will be noted that the member I00 may be a tank preferably holding oil from which by means of the pump [0| oil is pumped according to operative requirements from the lower interior portion of the tank orcontainer I00 through the medium of a suction pipe line I02 and is delivered under pressure from the pump through the pressure line I03 into a pipe connection I04 thence into'the upper end of the stationarily-supported depending tube 43 by which the lifting cylinder is carried and from which tube liquid under pressure is deliverable into said cylinder between the cylinder head 45 and into the region at the underside ofthe annular piston head 6| of the liftable piston element 60, A return or bleeder pipe line leads from the pipe connection I04 and embodies a-pipe section I05, an adjustable bleeder valve I06 and a terminal pipe section ID! that delivers the returning or bleeder liquid back into the supply tank I00. The bleeder line thus provided functions as means for controlling the outflow of the bleeder or release liquid from the region between the cylinder and piston heads just mentioned back into the tank particularly as and when the lifting load within the lifting means is' no longer required, to wit, at a time when the parts of the expansible and contractible lifting means 40 are assuming the contracting position relative to each other. The pump ml is actuated by and from a pump motor PM.

The electrical control system is diagrammatically imposed upon Fig. 3 and is now described in connection therewith.

Said electrical control system CS as a whole embodies the following features entering into its construction 1. Disconnect or power line switch A;

2. Main motor M with its respective control consisting of magnetic starter coil C with its magnetically-controlled contacts CI, C2 and C3, thermal overload heater unit HH, a series overload relay G with its relay actuated contact GI, a manually-actuated momentary-contact Start push button E and a manually-actuated momentary-contact Stop push button F;

3. Pump motor PM with its respective control consisting of magnetic starter coil B with its ma netically-controlled contacts BI and B2. Also a aacc'gooe 13 manually-actuatedmomentary contact. "Raise push button D for manual operation of motor PM;

4. Extremeupwarcll-lift limit switchJ andthermal overload heater unit switch-HS for the control' of both mainmotor M andpump motor PM. The electrical control embodying the foregoing features operates as follows:

I. The disconnect or power lineswitch A is manually closedtoconnect the sourceof. energy SE tothe control system CS and. motors M and PM.- When thenormally-open momentary-constant Start push button E is: pressed, then coil of the magnetic starter: for themain motor M is energized; thus closingv its normally-open magnetically-controlledcontacts Ci, C2 and1C3; The closing of the latter contact C3, which: shortcircuitsor bridges the normally-open: momentary-contact Start push button- E; maintains the energizationof coil C; thereby'holding closed its normally-open contacts C I, C2 and C3, name:- ly, after the normally-open momentary-contact Start push button E is-rel'eased.

II. Current then flows from thesource of energy through the disconnect or power line switch A, wire a, contact Gl, thermal overload heater unit HH, wire a and through main motor M; Then back tothe source of energy through wire d; seriesoverload relay G, contact C2, wire I),

and through disconnect'power line switch A to the source of energy. Main motor M, now'runningcauses the rotation of the rakearms.

III. An overload on main motor M would cause an increased-flow of cur-rent through the aforementioned path. Thisincreased flow of current through series overloadrelay G would cause it to be actuated, therefore closing its normallyopen movable-member contact GI, which short circuits or' bridges the normally-open momentary-contact Raise push button-D:- This causes coil B of pump motor PM magnetic starter to become energized, thus closing its normally-open contactsB l andB'Z.

IV. Current then flows from the source of energy through power line switch A, wire a, contact Bl, wire e, and through pump motor-PM. Then back to the source of energy through wire I, contact B2, wire b, and through power line switch A to thesourceof energy. Pump motor PM now running, causes the rakes to be raised (by means-of the hydrauliclift mechanism) progressively relieving the overload or main. motor M. This; reduces the current flowthrough main motor M ultimately allowing series overload relay G to reset, thus opening its contact GI. This results in opening, the circuit of coil B in the magnetic starter of pump motor PM, thusallowing said coil, B to become d'e-energizedandtopen its. movable contacts BI and B2; thusly disconnecting the pump motor PM from the: source of energy thereby allowing itto'stop.

V. If, however, the aforementioned overload on main motor M continued to exist inspite of the lifting action on the rakes, the pump motor PM would continue to operate, because of the continued increased current flow through the main motor M and its respective control circuit. This continued operation of the pump motor PM would cause the rakes to be lifted until said rakes reached an extreme position, whereupon a member of the lifted portion of the machine would operate the extreme upward-lift limit switch J and open its normally-closed contact, thereby disconnecting the source of power from the control circuits of both the main motor M and: the pumpmotor PM, causing; both: the main motor M and: the pump motor PM. to. stop; In this case the: original starting sequence described in paragraph I hereof must be followed: in order to restart main motor M.

VI; In the; event. the main motor M was overloaded to. the extent. where. it wasunable to drive the rake mechanisms because of some binding action on said rakes; or. in the: event mainmotor M is stalled because of some abnormaloverload, the thermal overload heaterunit. HHI which is in the main: motor M current. supply line, would become abnormally heated causingitsxnormallyclosed' thermal overload heater unit switch: contact HS to open. The thermal overload. heater unit switch HS, beingin both, the" control system of the main motorM- andfthe controlsystemzof pump motor PM; would disconnect. the control systemsof both themaiir motor M and. the pump motor PM from the source of energyandi therefore effect a stopping of both of said motorsbefore damage couldbe done to either the motors or any mechanical" member of the machine VII. The pump motor PM, which is the driv ing means for the pump Id! of the hydraulic lifting means, which in turn causes the lifting action on the rake arms, may be operated at will regardless of the existing load conditions by pressing toclose the normally-open momentary contact Raise push button D. This action is, in effect, the same as that produced by the aforesaid movable contact member GI of series over load relay G, only that this actionis. controlled manually. V

VIII. the main motor M and the pump motor PM maybe stopped, accordingto. the discretion of the operator, at: anytime regardless oii-the condition of load, or the position of the; rakes-,etc. by" pressing; to I open. the I normally-closed f momentary-contacts 012 Stop? push: button. station F;

Weclaim: I x 1 A mechanism of the class described; for use in a liquid-retaining basin having. a superjacent I frame structure and: comprising sediment-raking blades-y a liftable turna'ble carrier for the Blades; plunger means supported. from the'trame for raising and lowering the blade carrier; a driven turnable bull-wheel mounted from the frame: means eiiecti've between the bull-wheel and the blade carrier for turning the carrier-in various operative elevations thereof; and" a pnmary motor for turning the bull-wheel, characterized by an oil reservoir, a pump having a suction line leading from the reservoir and a discharge pipe'f'ordelivering pressure oil to the plunger when the pump is actuated, areturn pipe for oilfromthe plunger to the reservoir; an auxiliary motor for actuating the pump, and an energizable primary control for operating. the primary motor to turrr'the bladecarrier and having anautomatically shi-itable load-responsivecontrol member nor-madly innon-transmitting condition except when displ-aced'irithamabthere is a check valve in the discharge pipe for preventing back-flow into the pump.

3. Mechanism according to claim 1, in which the intake section of the discharge pipe has a check valve for permitting free forward flow from the pump into the plunger means but for preventing back-flow into the pump, and a pressure-gauge connected into said discharge pipe at a locality between the check valve and the plunger means. 1

4. Mechanism according to claim 1, in which there is an adjustable needle valve disposed in the return pipe for permitting contraction of the plunger means when overload conditions have been overcome.

5. A sediment-raking mechanism comprising a main driving construction having an annular supporting bearing of constant elevation and an open center bull-wheel mounted thereupon for turning movement about a vertically-extending axis; a vertically-extending lift shaft concentric .with the bull-wheel; rake armsextending from the shaft; a torque tube driven from the bullwheel and surrounding a portion of the lift shaft; and means by which turning movement is imparted from the torque tube to the rake arms, said mechanism being characterized in that it includes a fixed vertically-extending support tube concentric with said axis adapted for alternately receiving pressure liquid within and for releasing liquid from the upper portion thereof by having constantly open liquid flow passage area between the lower interior portion thereof and a confining liquid-receiving space between the cylinder and piston hereinafter referred to; a cylinder having a head secured to the lower end portion of the tube and cylinder wall rising from the head, a piston in the cylinder having an annular pistonhead encircling the tube and a hollow piston-rod rising from the piston-head to an elevation higher than that of the upper end of the cylinder walls, and an auxiliary turntable carried'from the upper end of the piston-head providing carrying support for the lift shaft.

6. Sediment-raking mechanism according to claim 5 having valve bleeder means leading from the support tube for releasing liquid and thereby lowering the piston after the lifting means has been expanded.

- 7. Sediment-raking mechanism according to claim 5 in which the lift shaft has a'cap having slidable, guidable engagement with and along the support tube.

8. Sediment-raking mechanism according to claim 5 in which there is provided an annular guide sleeve between the bull-wheel-and the exterior of the lift shaft.

tric with the bull-wheel; a torque tube driven from-the bull-wheel and surrounding a portion of the lift shaft; and means by which turning movement is imparted from the torque tube to the rake arms characterized in that it includes plunger means having a supported member and a liftable plunger member providing between them a pressure liquid-receiving space, a fixed vertically-extending support tube concentric with said axis adapted for alternately receiving pressure liquid within and for releasing liquid from the upper portion thereof by having constantly open liquid-flow area passageways at a lower end portion leading between the interior portion of the support tube and the pressure-receiving space, and an auxiliary turntable carried from the upper end of the plunger and providing carrying support for the lift shaft.

10. Apparatus according to claim 9, in which there is an annular member providing a guide sleeve between the associated bull wheel and depending torque tube on the one hand and the exterior of the lift shaft on the other.

11. Apparatus according to claim 9, in which an annular guide sleeve is provided between the bull wheel on the one hand and the verticallyliftable auxiliary turntable and lift shaft carried therefrom on the other hand which auxiliary turntable and lift shaft collectively constitute a vertically-movable unit and include means overlying the annular guide sleeve thus functioning as a stop that engages said guide sleeve and thereby determines the lowermost position of the lift shaft.

12. An apparatus according to claim 9, in which there is a liquid-holding tank, an associated pump having an intake section leading from the interior of the tank into the pump, a discharge section leading from the pump for delivering pressure liquid into the support tube, and a bleeder line leading from the interior of the support tube into the tank and embodying an adjustable valve whereby to control the back-flow of bleeder liquid into the tank and thereby providing for a progressive lowering of the plunger following a period in which the pump has been actuated.

FRANK L. GRANER.

CHARLES HAROLD SCOTT.

REFERENCES CITED The following references are of record in the file of this patent:

1 UNITED STATES PATENTS Number Name Date 1,702,192 Bloomfield et a1. Feb. 12, 1929 1,702,193 Bloomfield et al. Feb. 12, 1929 1,995,559 Andrews Mar. 26, 1935 2,140,059 Simonsen Dec. 13, 1938 2,291,836 Scott Aug. 4, 1942 2,295,943 Finney Sept. 15, 1942 2,360,817 Scott Oct. 17, 1944 1 2,467,409 Smith Apr. 19, 1949

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