US2624124A - Rotary drier - Google Patents

Description

Jan. 6, 1953 H. F. lRvlNG 2,624,124

ROTARY DRIER Filed Sept. 16, 1948 2 SHEETS- SHEET 2 INVENTOR.

E. /l/)nrad V230/7734 B m, ZM

Patented Jan. 6, 1953 .Henry F. Irving, Saginaw, Micha rassgnorT to .Baker Perkins, Inc.-,.` Saginaw,.Mich., .a corpora- "tion of `New 'York v.Application'September 16, 1948,1Serial No..49.',61'3

(Cl. S11-135) .8.Claims. i

Thisiinvention'relates toi-apparatus for .remov-l ing moisture from solid materials such'..as'salt or other crystalline lfor-"granular materials.

.It is. an object oithis .invention to provide apparatus of the aforementioned type which is constructedfas a compact machine lso as toY remove such moisture in amuchmore eficientand economical manner thanhas beenheretofore known in the art.

It .isa further object of lthis ,invention to provide .inapparatus -of '-the aforementioned ltype an improved final :drying-mechanism, Vinton which partial-lyV dried `solid materials may be'fed byl any suitable feed .mechanism,-and which will completely dry the solid materials in-a.rapid,-efficient and inexpensive manner.

Itis a further object of .this invention toprovde a mechanism of' the aforementioned-type inA fwhich the partially fdried'. material .is f ed into a rotatable, vdrying drum' and 'f axially 4moved through the drum while heated airA or' gas is passed therethrough'lson as :to completely dry it before itis discharged fromthe .-drum.

A further object. of this vinventionis to 'provide in-apparatus of the. aforementioned type, novelwmeans for .axially feeding or moving the material through' the rotatable drum.

,A 'further iobject of thisinventionfis-to provide inw-apparatus ofthe.- aforementioned` type, novel A means for vrotatably supporting and driving .-said. drum.

.- .It is.- a still further Aobject of this inventionrto provide an improved: :arrangement `for .directing andconducting heat from .exteriorly of the drum through the drumwall andthe material therein seas yto completely dry the .material as itis' .fed through .the container, and .so that the heated air passed through theA material' canbe recirculated, thus .saving power and fuel .consumption to the user.

A still further object of this invention Vis to provide in a rotatable drum of the aforementioned type, a novel peripheral wall construction which will break up the material being axially fed therethrough so as to facilitate the passage of the heated air therethrough for drying 'the material.

(Dther objects of this invention will become'apparent from the following detailedv description taken yinA conjunction with the accompanying drawings in which:

Figure l is a fragmentarysectional view of the final drying device-of this invention, and of the means Vfor lfeeding V.partially dried material thereto;

..2 Fig.2 is a lsectional view of thestructurefillustrated in Fig. 1 .takenfalong the line.2'-2 thereof 3 is a fragmentary sectional view of the structure illustrated inaFig. .l taken "along -the line 3-3vfthereof; and

Fig. 4 is. af-ragmenta-ry sectionalview of .the structure illustrated 1in Fig. 1 taken along the line 4--4 thereof. y

In removing rmoisture from lsolid materials,

. particularly salts such as-ammonium-sulphate,

sodium-chloride:potash, etc.,.it iscommon practice to employ centrifugal driers which are effective to remove a substantial Quantityof-liquid by centrifugal .force but which fcannot remove all of the liquid content. lIt is necessary, therefore, to complete thedrying operation 'by other meansl which will remove the residualliquid, usually amounting to 'from `about-one to five percent of themass. Machines for such nal'drying `operations have` been developedybutiithese have not been especiallyv eicient` and' economical to operate, especiallyfrom the .standpoint of power and lfuel consumption. The 4drying apparatus of this Yinvention has been developed for use in completing the drying of material which has beeny partially dried .-by'other fmeans such as any form of centrifugal drier. With such centrifugal devices;.a slurry containing an appreciable vpercentage of liquid is fed into the vdevice and the greater rpart of theliquid is separated from Ithe solidmaterial `by :centrifugal force. The materia-l :from thecentrifugal or other form of preliminary driermay be fedinto-the iinal drying device by any suitable means.

Thermal drying .deviceof the present inventionzincludes -asuitable stationary stand `or framework 9 .for rotatably supporting: a, drying drum -l I. Ahousing l2 surrounds the drum and operating .elements of the device. .The drum Y.H includes .at peripheralwall lI 5 which is vsmailer in diameter at thezinlet end thereof than at'the outlet-'end thereof, so` that the peripheral-wall is of agenerally frusto-conical shape.

The wall 'I5 is made up of avplurality of .concentric', axially overlapping and radially spaced cylindricall rings I1, f whichl are of progressively larger diameters from the inlet end tothe outletMend .of the'drum. The rings. Il Varefpositioned and -retained'in .the aforementioned over-v n lappingandv spaced relationshipy byan annular retainer vmember I8 which includesl aip'air'of annular track portions I9 'and 20 anda .plurality of circumferentially spaced axially v, extending' ribs 2| ,1 each of whichhastheinnerface thereof formed witha plurality 'of axially spaced-steps 22. Each of the rings I1 is secured to its respective step portion of the ribs 2l by means of countersunk screws 23. It will thus be appreciated that each of the rings I1 overlaps its adjacent ring of a larger diameter so that the inner surface of the peripheral wall I is stepped from the inlet end to the outlet end thereof, and spaces 24 are provided between the overlapping portions of the rings.

In order to rotatably support the drum II on the framework 9, a plurality of circumferentially spalced roller devices 29 are provided which are supported by the framework adjacent the drum peripheral wall. Each of the roller devices. 29 includes a roller 3I which engages the outer periphery of the annular track I9 and a roller 33 which engages the outer periphery of the annular track 20. The rollers 3| and 33 are rotatably supported in the framework 9 by meansl of a trunniofn 35. One of the roller devices V29 is connected with suitable drivingr means, such as an electric motor, in any conventional manner so as to rotatably drive the annular tracks I9 and 20 and the drum II secured thereto. The roller devices 29 and 33 therefore lboth. rotatably support and drive the drum II.

The housing adjacent the small end of the drum II is partially closed byan annular plate I4 which defines a coaxial inlet opening I3 for the drum through which material to be dried is fed by any suitable means. A screw conveyor feed comprising a tubular housing 5 and a screw 1 is illustrated. However, if the preliminary drier is a centrifugal drier lof the type in which material is moved axially along the interior surface of the rotating centrifugal drier drum and discharged off the open end or peripheral edge of that drum the centrifugal drier may Abe recounted coaxially, with respect to the drum II vwith the discharge edge of the centrifugal drier drum in the plane of the open end lof housing 5 so that the centrifugal drier discharges directly into the final drier of the present invention.

An annular wobble lplate 31 is positioned within the drum II at the inlet end thereof and projects radially inwardly fro-m the peripheral wall I5 of the drum II. The wobble plate 31 is provided on its outer periphery with one or more tabs 39 which fit into slots 4I in the innermost rings I1 so as to provide .a driving connection between the wobble plate and drum while permitting the wobble plate to move axially of the drum within the predetermined limits defined b-y the axial extent of the slots 4 I.

In order to impart wobbling action to the wobble plate 31, a plurality of circumferentially spaced roller assemblies 43 are provided. Each of the assemblies 43 includes a roller 45 kwhich engages the outer face of the wobble plate 31 and which is rotatably supported on a framework bracket 41 by meansl of a suitable bolt and nut 49 and bearing 5I. The framework bracket 41 is provided with a slot 53 through which the bolt 49 extends so that the roller 45 can be adjusted inwardly or outwardly with respect to the wobbleplate 31. The axes of the rollers 45 lof all of the roller devices 43 lie in a plane which is inclined with respect to a plane normal to the drum axis so that as the drum II and wobble plate 31 are rotated, the rollers 45 will cause the plate to wobble axially with respect to the drum.

In order to completely dry the material which is moved through the rotatable drum II, as will be hereinafter described, an air inlet conduit or passageway 51 is provided in the lower portion 4 of the housing 9 which directs heated air into the space within the housing and surrounding periphery of the drum. The heated air passes through the spaces 24 .in the peripheral wall I5 and into the 'interior of the drum I I through the layer of materia-l carried by the drum wall. A hot air outlet conduit or passageway 59 is provided in the housing I2 in an opposed relationship with respect to the inlet passageway 51 so that the heated air from the interior of the drum flows through the open. end of the drum and out through the routlet passageway 59.

, Any desired portion of the discharged air may be reheated and recirculated in order to reduce the amount of power and fuel necessary to heat the air. A material outlet passageway 6I is provided in the housing I2 adjacent the outlet end nf the drum I I, into which the solid material, in its fully dried condition, discharged by the drum for delivery into a screw conveyor o-r the like, not shown, which Iwill not permit passage of the air.

In operation, 'the partially dried material is fed into the rotatable drum through -the conduit 5 by means of feedjscrew 1, or otherwise. The material drops out of the conduit 5 down onto the wall I5 of the drum II, or, if the discharge is from the drum of a horizontal centrifugal drier, is thrown outwardly on to the wall I5. 'I'he drum II is rotated at a suitable speed'to maintain the material therein in a layer against the peripheral wall. The action of the wobble plate 31 will move the layer or cake of material axially along the peripheral wall toward the outlet end of the drum.

An important feature of the invention resides in the fact that the material forms a layer which is stationary with respect to the drum wall exceptinsofar as it'may be fed axially by the action of the wobble plate. The rate of feed may' be adjusted by adjusting the angle lof action of the wobble plate and thus the period during which the material is retained in the drum may' be adjusted as required to complete the drying action. The rings I1 are provided with internal cylindrical surfaces so that `no movement of the material toward the open end of the drum occurs except as the result yof the action of the wobble plate 31. It will be apparent, however, that the inner surfaces of the rings I1 may be madey frustov-conical, so long as the conical angle is insuicient to cause the material to slide out the end of the drum as the result of centrifugal force.

It should be noted that while the drum and material therein are rotated, drying action results entirely from the flow of heated air through the layer of material, Accordingly, it is essential to prevent the layer of material from forming a solid cake which would prevent such air now. This result is achieved with the minimum power requirements as a result of the fact that the drum is generally conical in form.- Thus, as the layer is progressively moved from the small to the large end of the drum its diameter progressively increases. This keeps the layer broken up into a loose mass through which the air may flow. The stepped arrangement of the rings I 1 is peculiarly advantageous in this connection since the layer breaks up as it moves off the discharge edge of each ring and it is at this point that the air inlet passages 23 are located. A further advantage of the stepped and overlapping arrangement of the rings I1 is that it provides air inlet openings which face in a direction parallel to the direc-A .tionmitow of thematerial'.fand-hence:cannot become'clogged. i

VThespeed of vrotationiofthe .drum'isnot crit-ical soi long'. as itis sufficient' to retainithe material lna relatively stationary layer onv its inner "surface. lf ther drier .is lconnected directly; tto the discharge end .of a .centrifugal drier drumpwhich drums rotate ata very high speed, itis necessary to rotate the drum 1,5" ata speed sufcientato prevent thelivmaterialirom sliding: helicallyout through the' drum .as theresult of the'high--speed With1 which' it is vdisclrs-rrged.tangentially byl'the centrifugaly drier.

.v Satisfactorygresults lhave-been achieved with .drum speeds in the order of 1.70R. PJ M'ior la drumhaving, a maximum diameter of 24.fwhen the. material `tohe dried: was received .directly from a zcentrifugal drier in the manner 'indicated above.

While the invention. is illustrated Aas embodied in a. *machineY having a drum mounted on a horizontal axis, vthe principles and advantagesbfthe invention may be're'ali'zed vby a" machine having a vertical Vaxisdrum vsince the force of gravity has negligible effect as compared with the centrifugal force holding'thematerial against the drum Wall. In the case of :vertical axis .machines in which the drum discharges upwardlyithe rings I1 may be made slightly frusto-conical so that they are of larger diameter at their upper edges in order-to facilitate discharge of the material.

'What is claimed is:

1. Apparatus for completelyremovingmoisture from solid materials, including a frame; a drum rotatably supportedonsaid"frame and into one end of which such material is adapted to be fed, said drum having openings formed in theperipheral` Wall thereof, amech'anism' connectedwith said drum forrotatingV said drum so that the material fed therein will be centrifugally held 6 ofi not gases .therethroughfand' 'means for I "congducting kanditransmitting `het :gases from exte- @riorlyof the drum through 'the openings "in the 'drum periipheralfvvall and the layer ofi material supported thereon.

v"3. Apparatus for-removing moisture from solid materials, including a' frame, a drum rotatably supported :lion said frame and into one end-of Which/such material is adapted to be fedxand lfrom'l'the opposite end of `which such material islada-pted to be discharged, .said rotatable drum includingra-peripheral lWall Which is smaller lin diameter atthe inlet end thereof than at'the discharge end-said peripheral Wall beingmade upof a plurality of vconcentric rings of progres- ,sively` increasing diameter arranged infaxially i drum/for rotating-said drum so that the material which :is fed th'erein `will be centrifugally held 5 against-said peripheral lvv'all in'the vform of a lay-erewhen said drumis rotated, a plate element connected.`v tov said drumadjacent the inletV end thereof-fforrot'ation therewith and 'axial move-l Y ment relative thereto, means `for axially actuating said/plate element so as to axially move the inater-ial'vheld against said peripheral `yvallfrorn the inletend of said drum tothe-outlet end thereagainst the peripheral wall thereof when said l drum is rotated, a member connected with said drum for rotation therewith and movable axially for moving the material therein from the inlet end thereof to the discharge end thereof, means for oscillatingr said member axially of said drum during the rotation thereof, and means for conducting and transmitting hot gases from extey riorly of the drum through 4the openings in the peripheral Wall of the drum and layer of material supported thereon.

2. Apparatus for completely removing moisture from solid materials, including a frame, a drum rotatably supported on said frame and into one end of which such material is adapted to be fed, said drum including a peripheral Wall of a generally truste-conical shape which is smaller in 0f,-a.'nd means `for transmitting and conducting hot vgases Jfrom exteriorly of said drum through said J peripheral 'wall' air passageways andthe layer-oi material supported thereon for completelydrying the latter as `it is axially moved through.v said ',.drum` l (l. Apparatus for removing moisture fromf's'olid materia-lsfin'cluding a fra-me, a drum rotatably supported on said frame and into one end of which such material is adapted to be fed, said drum including a peripheral Wall against which the material is adapted to be held in the form of a layer by centrifugal force when said drum is rotated, said peripheral Wall having a plurality of openings therein, means for conducting and transmitting hot gases from exteriorly of the drum through said peripheral wall openings and the layer of said material supported thereon, a plate extending radially inwardly from said peripheral Wall adjacent the end of said drum into which the material is fed, means operatively connecting said plate to said drum for rotation therewith While permitting relative axial movement diameter at the inlet end of said drum than at the opposite end, said peripheral Wall having a plurality of openings therein, mechanism connected with said drum for rotating said drum so that the material Which is fed therein will be heldr as a layer against the peripheral wall by centrifugal force when said drum is rotated, a

member connected with said drum for rotationv therewith and for axial movement relative thereto for axially feeding the material in said drum from the inlet end thereof towards the opposite end thereof, means for oscillating said member axially of said drum during the rotation thereof, said frusto-conical wall being stepped so as to cause said material layer to break up into a loose mass as it moves from the small diameter inlet end of said drum toward the larger diameter discharge end thereof, and facilitate the passage between said plate and said drum peripheral Wall within predetermined limits, and means engaging said plate for Wobbling the same axially so as to move the material in such drum axially thereincluding a peripheral Wall made up of a plurality of rings of progressively increasing diameters i which are arranged so that each overlaps its adjacent member in radially spaced relationship, means connecting said rings in said overlapping .and spaced relationship so as to provide air passageways therebetween through which hot gases may iloW, mechanism connected with said drum for rotating said drum so as to centrifugally maintain the material therein against the periph- 7 eral wall thereof, means for directing hot gases from exteriorly of said drum through the peripheral wall air passageways, in order to dry the layer of material in said drum, a plate element extending radially inwardly from said peripheral wall adjacent the inlet end thereof, means operatively connecting said plate to said drum wall so that Isaid plate will rotate with said drum, While permitting relative axial movement between said plate and said drum within predetermined limits, and means engaging said plate for wobbling the same axially of said drum so as to move the layer of material axially along said peripheral wall and out the discharge end thereof.

6. Apparatus for removing moisture from solid materials including a drum having an inlet end into which the material is adapted to be fed and an outlet end through which the material is adapted to be discharged, ysaid drum including a peripheral wall which is smaller in diameter at the inlet end thereof than at the discharge end, said peripheral wall being made up of a plurality of ring members of progressively increasing diameters which are arranged so that each member overlaps its adjacent member and is radially spaced with respect thereto, means securing said members in said overlapping and spaced relationship so as to provide air passageways between said rings through which gas may oW from the exterior to the interior of the drum, and a member connected with said drum for rotation therewith and for axial movement relative thereto for moving material through said drum and in contact with the walls thereof axially from the inlet end thereof to the discharge end thereof, and means for :oscillating said axially movable member axially of said drum during the rotation thereof.

'7. Apparatus for removing moisture from solid materials, including a drum into one ena of which such materials are adapted to be fed, a peripheral wall for said drum, a plurality of air passageways in said peripheral wall which extend substantially parallel to the axis of said drum, and a member supported by said drum for axial movement relative thereto for axially moving such materials through said drum from one end to the other. and means for oscillating said member axially of said drum during the rotation thereof.

8. Apparatus for removing moisture from solid materials, including a frame structuhe, a drum rotatably supported by said frame structure and including a peripheral wall, a plate like element supported for rotation with the drum and axial movement relative thereto, a plurality of circumferentially spaced roller devices supported by said frame structure and engaging said plate element at circumferentially spaced points, said rollers being in a plane which is inclined with respect to a' plane normal to the drum axis so as to wobble said plate axially with respect to said drum when the latter is rotated.

f HENRY F. IRVING.

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

UNITED STATES PATENTS 306,748 Germany 1 Jan. 26, 1916

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