US2418973A

US2418973A - Thickener

Info

Publication number: US2418973A
Application number: US431438A
Authority: US
Inventors: Hardinge Harlowe
Original assignee: Hardinge Inc
Current assignee: Hardinge Inc
Priority date: 1942-02-18
Filing date: 1942-02-18
Publication date: 1947-04-15
Anticipated expiration: 1964-04-15

Description

April 15, 1947. H, HARDlNE 2,418,973

THICKENER FiledFeb. 18, 1942' 4 sheets-sheet 1 H. HARDINGE April 15, 1947.

THICKENER Filed Feb. 18, 1942 4 Sheets-Sheet 2 f w m April 15, 1947- H HARDlNGE 2,418,973

THICKENER Filed Feb. 18, 1942 4 sheets-sheet s 6M MMM @www April 15, 1947;.

H. HARDINGE THIGKENER Filed Feb. 18, 1942 4 Sheets-Sheet 4 f www w w M W Patented Apr. 15, 1947 Harlowe.

Hardinge; York, Pa.,

assigner to Hardinge Company, Inc., York;Y Pa., a corpora-- tion of-New York.

Application February-18, 1942; SerialNo. 431,438

5; Claims. 1fy

The present invention relates generally to sedimentationy apparatus 0i" the thickener'type-and speciiically to mechanism for relievingv strainson the-moving'parts of such apparatus. While the principle underlying thisinvention is particularly adaptable to center pier thickeners employinga central methodvof driving the Scrapers, its application is not limited to suchv apparatus but is equally applicable to the so-called truss construction or thickener using beams supported at thetankTim;

In the thickeningoperation, large masses of solidsf'ofteny accumulate inthe tank; sometimes due to clogged' sludgev discharge or sludgel dis-- charge of insufiicient capacity; these solidsy build up. yon the sides ot the tankr and the Scrapers, then drop oifj' causing a massive bank of material in the path of the Scrapers. Still again, a heavy tooi'or other foreign substances may bedroppedinto the tank. such an obstruction occurs, an overloadis placed on the scraping mechanism` citen resulting in complete breakdown. of the machine beforethev obstruction can be removed.

Various attempts have been made in' the past to overcome this difcultylby raising-thescrapers or a'portionof the Scrapers above theobstruction, but inall cases, in my knowledge,- the `designs'for these strainerelev-ing mechanisms have-had 1 inherentldisadvantages.

Thel principal object` of f my invention is vthere-V foreA to provide means havingy a maximum operating eiiiciency and adap-tedto relieve-the strains imposed: on the scraping mechanism.- o sedimentation apparatus" and therebyy preventing costly' breakdowns andi interruptions` to operaL tions, aswellas` permitting a designy usingknown maximum torce requirements;

Another objectisto provide a mechanism` for raisingthe scraping rakes in thickening apparatus that will function onlywhena certain minimum overload'has 'been' placed?on'saidrelies;`

Yet another object is to providefa'A mechanism forraising the vTakes which willallow the rakes to functionv normally untill a. substantial overloadl has been. imposed on'` them and then; cause.`r the rakes ,as aunittto move verticallyT upwardlywhen an immovable obstructionisencountered by the rakes...

Another important object isfto provide means whichv impart torque' to the rakes f. of a thickener and also: function to raise/thefrakes. as; a. unit when anoverloadzis placedon them;.said means producing: a raising force .which increasesy pro-- gressively as the rakesarerais'ed;

`at other timesr In all cases wheny AiA further object isf'toV provide` warningk means? operable at a predeterminedv height' of .f the.. rake.:

toindicate a serious -overloadedfcondition .of thev thickenerrand :additional means-to stop. operation ofvr the-thickener; shouldthis .overloadznot he ,reg-.l

lieved.

Other objects and advantages will. lne-"apparentA to,.thosesskilledinzthe art from the followingadescriptiony and; by. reference-Lto. the vacconnanying drawings.l

` Intheidrawin'gsr Figure 1 is'ra transverse sectional view. ofa. thickene'r.: which incorporates lmy improvements; Figure .2 is. a plan `View* of theapparatusishown in Ei'gure 1;

Figure 3 isv arplan view, ypartly broken away,l of, thepoperatingfmechanism;

Figure-4 a.:transverse-,.se,ctional:view:through the4 mechanism: housing showing theoperating mechanism -in side elevation;

Figure 5 is a transverse sectional viewtaken along the line 5. of v Figure 3 llooking -in the. -direction` of `the arrows; andr Figure' is a. simpliiielv diagramof the electrical connection. to the warning andy shut-ofi devices..

Brieiiy, my inventioncomprises an annular sedimentation tank 1 in the, center ofwhioh is; a vertical', pier or column which supports a cylindrical housing. Carriedby the housing and revolubleytherein is: a flanged ring gear. driven; at reduced speed by an electric motor mountedion the-1 housing.4 A torquey tub'efsurrounds; the column; and has; one of its ends. externally; anged and projecting through and abovethe plane of theringgear.. The. opposite-end of the torque tubek has, attached. thereto. the scraping. rakes of the thickener whichare adaptedito; movesete tledsludgetoward thecenter of the tank..

Between'y the flanges of.. the ring. gear. and .the torquetube, and attached'theretofor universal movement, are apluralityof pushrodsfdisposed at equal acute kanglestofthe planes' ofthe flanges. These rods are adaptedto impart the-.torque of. the ring gear 'tothe'tubee'and thence to. therakes, givingY themty a. rotaryl movementV in. thev tank.' However, should a load* occur in thetank which' isfincapable of being moved by thexnormal opere'- atingV positionv of: theirakes, which is adjacent. the bottom. of. thegtank; the:v angle ofi these push rods is increasedby the driving torqueiof the gear, resulting in` avertical'displacement of the torque tube: relative` to, the: gear and: consequent; raising.of .the rakes'to; a; moreflui'cb stratumpf the: sludge;v

The normal angle of the push rods is of such degree that the rods will produce only their torque imparting function to the rakes until a considerable force has been imposed thereon before they will be displaced to raise the rakes. However, once this overload point is reached, the raising force imparted by the rods increases rapidly as they approach the vertical. rlhis arrangement maintains the rakes at their normal operating level until an obstruction which would cause a serious overload on the rakes and drive has occurred. However, after such overload has been imposed, the rakes will rise quickly and easily above the obstruction.

Stops are provided to limit both the upward and downward movement of the torque tube.

A pair of superposed electric, circuit closing, switches are positioned in the path of vertical movement of the torque tube to be operated thereby when the tube approaches the limit of its upward movement. The lower of these switches operates an audible alarm to indicate to the operator of the machine a dangerous overload. The upper of the switches is adapted to be contacted by the torque tube should it rise above the first switch and functions to stop the driving motor of the machine.

As illustrated in Figures 1 and 2, the sedimentation apparatus comprises a settling tank I having an annular vertical side wall 2, the rim of which is provided with an overilow trough 3 adapted to be drained by an `efiluent conduit 4. The bottom of the tank is conical and has at its apex an annular discharge basin 6, having in communication therewith, a discharge pipe 1 connected with a diaphragm pump 8. A control valve 9 is interposed in the pipe 8 for controlling the rate of discharge. A high pressure water line I0, likewise valve-controlled, is also connected into the discharge line 1. This facilitates the discharge of solids through line 1.

Projecting upwardly from the bottom 5 and concentric with the side wall 2 is a vertical pier I I which supports a superstructure I2, which carries the operating mechanism for the thickener and which will be described in detail later.

Surrounding the pier II is a torque tube I3 having rigidly attached to the lower end thereof a plurality of plows or rakes indicated generally as I4. These rakes are adapted to rotate around, and are also capable of vertical movement with respect to, the pier II. The rakes may be of any suitable construction but, as illustrated, each comprises a trussed arm I5 extending radially from the torque tube I3. The lower beams of the arms I5 are angularly disposed to correspond to the conical angle of the tank bottom 2 and are provided with a series of angular scrapers I6. Supplemental spiral Scrapers, as indicated at I6', may also be attached to the arms I4. The Scrapers I6 and I6 are adapted to move adjacent the bottom 2 when the rakes I4 are in their normal operating position to move settled sludge toward the basin 6.

Access to the superstructure I2 is obtained by means of a catwalk I1 supported at one end by the superstructure and at the other by a pier I8 carried on the rim of the wall 2. Suspended 'beneath the catwalk I1 is an inuent launder I9 adapted to feed material to the tank I through a stilling well 20 with which the inner or discharge end of the launder I9 connects.

As stated above, the superstructure I2 carries the driving mechanism for the scrapers. This superstructure comprises a housing 25, Figure 5,

composed of a cylindrical eide wall 26 and a top 21 attached thereto. Projecting downwardly from the center of the top 21 is a flanged tube 28 secured to an upper flange 29 of a second tubular member 33 which is provided at its lower extremity with a substantially wide ange 3|. The tube 30 is attached to the upper end of the pier II by means of anchor bolts 32 which pass through the flange 3 I.

Carried within the housing 25 near its lower end is a ball race 33 suitably attached to the cylinder 26 by means of brackets 34. The race 33 is provided with balls 35 which support for antlfrictional movement a ring gear 36 which is provided with an internal flange 31. The gear 36 is adapted to mesh with a pinion 38 attached to one end of a shaft 39, the lower end of which is supported in a bearing 40.

The shaft 39 extends through the top member 21 of the housing and is journalled in a bearing 4I of a gear housing 42. The housing 42 contains a Worm gear 43 which is attached to the extreme upper end of the shaft 39 and meshes with a worm 44. The worm 44 is driven by a geared motor 45 by means of a chain drive indicated generally as 46.

The torque tube I3 which, as stated, carries the Scrapers I4 at its lower end, surrounds the pier II and is disposed concentric with the ring gear 36 and has rigidly attached to its upper end an annular Flange 48, to the inner circumference of which is fastened a depending sleeve 49 which ls concentric with the tube I3. The inside diameter of the sleeve 49 is approximately the diameter of and surrounds the iiange 3l of the tube 30 and forms therewith a slide bearing for aligning the upper end of the torque tube I3` A second slide bearing member 5I is attached to a sleeve 52 secured, as is shown in Figure 1, to the lower end of the pier I I. This bearing member 5I concentrically aligns the lower end of the tube I3 with the pier and, together with the sleeve 49, provide for substantially vertical movement of the torque tube I3.

To transmit the rotational movement of the gear 36 to the tube I3 I provide a plurality of push rods 53. These push rods are arranged circumferentially and equidistant around the torque tube I3 between the gear ange 31 and the torque tube flange 48. As shown in Figure 3, three of such rods are employed. However, more or less may be used depending on the size and operating conditions of the thickener.

The push rods 53 are provided with turnbuckles 54 for longitudinal adjustment and their lower ends are pivotally mounted in bifurcated eye members 56 which, in turny are swivelly held in annular rings 51 securely attached to the upper face of the flange 31 of the gear 36. The upper end of the rods 53 are similarly pivotally attached as at 58 into eye members 59 swivelly attached as at 6U to the underside of the torque tube flange 48. These push rods are disposed at an acute angle to the planes of the gear flange 31 and the torque tube flange 48 and are inclined toward the direction of rotation of the gear 36. By means of the pivotal and swivelling connections of the rod 53 to the driving gear 36 and the flange 48, they are capable of angular displacement with respect to these members.

As Shown in Figure 4, the full line position of these push rods 53 indicates their angle for normal operation of the scrapers I4, that is, when the Scrapers move adiacent the bottom of the tank I. This position is maintained so long as andere the 'downward forceexertarty2 thewei'ght of the i rakes andtorque tube exceeds `the drag'imposedl on the rakes by the sludge in the tank.` The' amount ofthisdrag is dependent upon themassv density of the material'in the tank'through which" the rakes must move. Should this densitybe- Mounted on the upper face oflthe gear 'nangef 31v are a'v plurality of support members 6I pro-V vided at their upper extremities with resilient pads y61|'. These pads 6I'. are adapted to contact the outer edge oftheilange 48v and serve as a limit stop for the lowest position of'the rakes Ill.` Thelength of thesupport member 6I is such that when the flange 48'y isinf contact with the pad GI the rakesl I4 will beiin their normaloperatingposition adjacent the bottom of the tank I .Y

Toy provide limitfor the upward movement ofV thev rakesk I4, rigid fingers E52-r project radially in'- wardly fromthe flange 3T to a point adj acent the periphery of the tube I3.'. The inner ends oi these lingers t2' are in'thepath of movementofradiallugs Iii',` secured to the outer surface of the torquev tubevI. Aswill be seen from Figures 3r and'l,

as the tub-e rises and revolves-relativeto the gear' 36:! to.` itsfiextremeupperl limit, the lugs 63 will contact the fingers 62 and thereby' prevent any further displacement of 'the' torquev tube with respect to the driving gear.

Attached to the under face of the top member 21er ther housing 25-isa` depending bracket 64.

This'bracke-t 64 carries at its' lower end a pair' of superposed circuit-closing switches 65 and 65' provided rwith'operating arms 51 and 68, respectively. The-bracket 64 is soposition'edthat the ends ofthe operating arms 61 andGS will bey in the path of movement of the upper end of the sleeve V49 to be contacted thereby as the torque tube I3 rises to its upper position. The lower of these switches 65, that'is, the iirst'to be contacted by the sleevey 49, completes thecircuit, asis shown in Figure 6, from a source of current `69 to avvarn-v ing device 1D, such as a bell. The upper of the switches Eil, adapted to be closed bythe sleeve 49 afterit has moved past the switch 65, is adaptedto complete the electric circuit from the source of current 69' to a relay 1I which, in turn, supplies electrical energy to stop the driving motor.45.

In operation, liquid in which solids are suspended is fed to the tank l through theinfluent launder I9 where ther suspended solids settle to the bottom of the tank. Theseasolids are scraped inwardly toward the center discharge basin by rneansv of the rakes I4 which slowly revolve over the bottom of the tank driven by means or the motor 45 through the-medium of the gear 36, push rods 53` and thetorque tube. I3. The solids thus scraped are withdrawn from the basin through discharge line 'I by means of the pump 8. Liquid in the tank overlowstheriminto the trough 3 where it is withdrawn through the eilluent conduit 41.

.During theY sedimentation -process solids someiput or for other reasons.

timesfbuildfup-in'lthe center oftheltankby iii@- suicient discharge rate through the-discharge line 1. This maybe caused-bya clogged'lineginsuicient pumping rate, too'higharate orin- Also during thev settling process,V sludgemay accumulate on'l the side walls ofthe tank andon the blades of vthe scrap'- ers. When suicient sludge` has so builtup, it will fall from.thesesuriaces-solas to cause a heavy deposit orbank of solids in thel pathl of move-'-A` ment of the scrapers. Either or both of these extraordinary accumulations' off! solids, asy well as any heavy foreign substance dropped into-*the tank, will cause' an overload on thev scrapers`- and their driving mechanism.

To permit of 'a reasonably heav'y'operating'load forw the machine whereby its' full capacity may -be utilized, a'certain amount of such overloading must be permitted. However, should theove'ra 'loadinglreach a degreethat it would-imposea seri-YV ous strain on'either the rakes or` theo-pe-ratingf mechanism, this overloading must-be` rapidly'an'deasily-relieved.

Mynovel arrangement of push rods angularlyV i disposed in the direction of rotation of the driving gear rwill permit both of these functions, thatI is, maintain normal operating conditions of the rakes until a serious or substantial overload oc curs, and then because of'their inherent char-` j acteristics will cause the rakes to bemovedfrap'- i idly wtih constantly increasing moving force above the obstruction from which pointltherakes will either bytheir normal function gradually fre-I duce this obstruction orwil'l remain inl thisraised.

position until this obstructionislmanuallyf r'ei moved.- Should `the obstructionv iny Vthe tank". be such as to cause the rakes to movey toitheir ex tremelupper limit; the sleever49: onthetorquel tube I3 will contact and1close'the'switch`65 operating thereby ani alarm to indicate to the` op eratorof the machine that a serious obstruction hasbeen formed in the thickener, which obstructionlinust be removed' either by increasingV the rate of discharge .orclearing the discharge' pipe or,r if these fail, by manually removing the obstruction 'fromlthe tank. If for som'ereason'this.` obstruction is not removedfor instance,` iilthe operator is engaged elsewhere' or is incapableY of rapidly removingithe obstruction-the torque tu'beir will continue to risef past the warning switch 65l and contact to close the switchl. When this switch is closed, circuit is completed tov the' con'- trol circuit of the motord to stop this motor and stop themovement of the rakes.-

Thus it will'b'e seen I have devised van' op'erat`F ing mechanism' for sedimentation apparatus l which has such characteristics as to permit-op-y eration of the apparatus at an optimum eiiiciency whereby the maximum capacity of the machine Amay be utilized.

with the above by which a warning alarm is*- iirst given to indicate a dangerous obstruction which, if not removed, Will cause the driving mechanism of the apparatus to stop.

While I have shown and described the preferred embodiment of my invention, I Wish it to be understood that I do not confine myself to the precise details of construction herein set forth by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

I claim:

1. Apparatus for treating liquid containing solids comprising a tank for the reception of a mixture of liquid and solids, a support mounted for rotary and vertical movement Within the tank, blade members carried by the support and adapted to impart motion to said solids in the tank, a rotary driving member mounted for rotation coaxially with the support and in a xed plane perpendicular to the axis of rotation of the support, means for actuating the driving' member, push rods flexibly connecting the driving member and support, said push rods being inclined upwardly from the plane of rotation of the driving member and in the direction of rotation thereof for imparting a lifting force to the support to raise the same and the bladed niembers when an overload of solids is imposed on the latter.

2. Apparatus for treating liquid containing solids comprising a tank for the reception of a. mixture of liquid and solids, a support mounted for rotary and vertical movement within the tank, blade members carried by the support and adapted to impart motion to said solids in the tank, a rotary driving member mounted for rotation coaxially With the support and in a iixed plane perpendicular to the axis of rotation of the support, means for actuating the driving member, longitudinally extensible push rods flexibly connecting the driving member and support, said push rods being inclined upwardly from the plane of rotation of the driving member and in the direction of rotation thereof for imparting a lifting force to the support to raise the same and blade members when an overload oi' solid is imposed on the latter, and means for adjusting the length of said push rods the angle of inclination thereof with respect to the driving member.

3. Apparatus for treating liquid containing solids comprising a tank for the reception of a mixture of liquid and solids, a support mounted for rotary and vertical movement Within the tank, blade members carried by the support and adapted to impart motion to said solids in the tank, a rotary driving member mounted for rotation coaxially with the support and in a xed plane perpendicular to the axis of rotation of the support, means for actuating the driving member, push rods flexibly connecting the driving member and support, said push rods being inclined upwardly from the plane oi rotation of the driving member and in the direction of rotation thereof for imparting a lifting force to the support to raise the same and the bladed members when an overload of solids is imposed on the latter, and cooperating stop members carlied respectively by the driving member and support for limiting vertical movement of the support.

4. Apparatus for treating liquid containing solids comprising an annular tank for the recepto thereby adjust f tion of a mixture of liquid and solids, a vertical pier mounted centrally in Said tank, a. tubular torque member rotatable about the pier and movable axially with respect thereto, blade members carried by the lower end of the torque member and adapted to impart motion to the solids, a. rotary driving member mounted for rotation in a iixed plane perpendicular to the axi's of and intermediate the ends oi the torque member, means for actuating the driving member, push rods flexibly connecting the driving member with the torque member adjacent the upper end thereof. said push rods being inclined with respect to the plane of rotation of said driving member and in the direction of rotation thereof for imparting a lifting force to said torque member and blade members to raise the same yWhen an overload of solids is imposed on the blade members, and cooperating guide means associated with the pier and torque member for guiding the latter and blade members in substantially vertical movement.

5. A sedimentation apparatus comprising an annular tank for the reception of a mixture of liquid and solids, said tank having an inlet and an outlet, a vertical pier positioned axially within the tank, a tubular torque member mounted for rotational and axial movement with respect to the pier, a scraping device carried by the torque member adjacent the lower end thereof, for moving said solids toward the outlet, a supporting member carried by the pier, a horizontal driving member carried by the supporting member for rotation ooaxially with the torque member, said driving member being capable of relative rotary movement with respect to the torque member, means for rotating the driving member, and push rods having a pivotal connection with both the driving member and torque member to rotate the latter, said push rods being inclined normally upwardly from the plane of the driving memberand in the direction of rotation thereof, the angle of inclination of said push rods being increased upon relative rotary movement of the driving member with respect to the torque member due to the application of an overload of solids on said scraping device to impart a lift force to the torque member to raise the scraping device relative to 'said solids.

HAR-LOWE' HARDINGE.

REFERENCE S CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 2,265,046 Sabin Dec. 2, 1941 2,295,943 Finney Sept. 15, 1942 1,509,39 Blomiield Sept. 23, 1924 1,962,646 Logue l- June 12, 1934 2,122,287 Kepper June 28, 1938 2,239,194 Fitzgerald et al Apr. 22, 1941 2,253,535 Weinig Aug. 26, 1941 2,262,4i2 Weinig i Nov- 11, 1941 1,227,107 Blomeld May 22, 1917 1,734,044 Orr Nov. 5, 1929 1,907,746 Daman May 9, 1933 2,126,884 Hardinge Aug. 16, 1938 2,226,974 Hardinge Dec. 3l, 1940 2,286,397 Weiss et al. June 16, 1942 FOREIGN PATENTS Number Country Date 2,286 Australian Oct. 31, 1931