US2536762A - Drier - Google Patents

Description

Patented Jan. 2, 1951 UN-T) *STATES ENT GFFC mmm` Kenneth EgMcConnaughay, West Lafayette, Ind.

Application IAugust 2, 1944 v'Serial No. l5475668 s claims. (o1. effi- 135) .My invention relates 'to driers oi the rotary drum type vsuch as are commonly used .in the .drying or crush-ed stone or other :aggregate intended for incorporation ina paving composition.

As heretofore made, such .driers have usually lsupplying aggregate to them requires .special elevating equipment.

lIt is the .object of my invention to produce .a .drier which .will be more compact than the com- :monforin of drier, which requires no extra means lfor elevating aggregate to its inlet.end,rand which /will operate to remove moisture vfrom the aggregate .quickly vand eiciently.

vIn carrying out my invention, Iemploy a -Iotatring drum .having co-axialportions .of widely diftering diameters, each 'portion being provided with aggregate-elevating nights. The drum is .mounted for rotation with its axis inclinedfdownwardly from rthe larger-diameter portion of lthe drum. The open end of the larger-diameter portion of the drum is closed by a stationary plate provided near its bottom lwith openings for the admission of aggregate and heated air-and near its .top with an opening for the discharge of air. Aburner or other suitable means supplies heated air to the larger-diameter portion of the ydrum through the air-.inlet opening, vwhile a second 'burner or other means supplies heated air to *the 'discharge end of i the smaller-diameter drumportion. In the preferred form of the invention, an adjustable means is provided for Vregulating the rate at which aggregate is vfed from the larg- Ver-dianieter drum portion to the smaller-diameter drum portion.

The accompanying fdrawing illustrates lmy in'- Vention: Fig. 1 is a side elevation of the ldrierwi'th portions of the drum broken away Vto illustrate the internal construction; Fig. 2 is anc/end elevation vof the drum; and Fig. '3 isa' fragmental Y,

plan View of the interior of the drumv illustrating a -means which may be employed Vto control the rate at which the material vbeing -dried is fed into the smaller drum-portion. 1

i The drier-drum illustrated in thed-rawingcom..

:prises Jal'argef-diameter portion I0 and a smalldiameter portion i! joined by .an annular end wall 1&2. The smaller-diameter .portion Il is .provided withaxially spaced supporting rings I3 rezo'eived in the .grooves of grooved rollers Ul rotatably mounted on a base frame l5. A sprocket Al mounted on the drum-portion H is connected by a chain il to an electric motor 'i8 or other .source oi Vpower by means of which the drum is rotated.

- The drum-supporting rollers lli are so arranged Ion the base frame I5 that the drum lli-li is .supported in a position with its vaxis extending downwardly from the larger-diameter portion l5) to the .open end olf the smaller-diameter portion H. To aid in transmitting to the base frame the axial .thrust resulting from this inclined position of the drum, the base frame may be provided iwith rotatablymounted rollers 2i) engaging the outer surface :of the annular .wall l2.

lnteriorly, .the larger-diameter portion I0 of .the drum is .provided with an annular series of .aX'iallyeXtending iiights 2i, while a similar annuf lai' :series yof nights 22 is provided within the smaller-diameter drum portion ll. As will be obvious., these ,flights operate when the drum is .rotated A.to elevate the aggregate passing through .the drurnand .to .drop it across the drum.

`.control the rate at which aggregate is fed from the drum portion .itl .into the drum portion lui, the latter maybe .provided with a feed-scoop ',-li'swhich extends'circumferentially of the smaller .drum-.portion andprojects axially into the larger .drum-portion It. As shown, thescoop. Z5 is vadjustable to vary the extent to Which it projects 'intothe drum portion it, and hence to vary the .amount oi aggregate which the scoop intercepts vat-each drum-revolution. Such adjustment of the .scoopis conveniently effected by securing it lto the circumferential wall of the drum-portion 4H .by bolts 2t which project outwardly through .longitudinally .extending slots 2l in the drumwall.

.Theopen endof the larger drum-portion I@ is :covered Vby .a stationary plate 3@ supported in appropriate manner from the base frame l5. In one fof .the lower quadrants of the plate 3d, there is provided an air-admission opening Si, and. in `the other vlower quadrant there is an aggregateadmitting opening associated with a hopper '32 Whi'chprojects outwardly from the plate 3E. The hopper is conveniently so dimensioned and positioned that a dump-truck can discharge its lo-ad directly .into it. Mounted outside the opening 3l and Ain general alinement vtherewith is a burner .than its assarea ciate with the exhaust stack some means for into discharge thereinto a flow-inducing jet of airv or steam.

In operation, the burners 33 and 34 are ignited, the motor I8 is started to rotate the drum, and aggregate is supplied `to the hopper 32. The aggregate so supplied enters the lower part of the large drum-portion lil, and is carried upwardly along one side thereof by the flights 2|. As those flights successively reach an inclined position above the drum-axis, the aggregate resting upon them falls under the influence of gravity through the heated atmosphere created by the burner 33. The burner 33 is desirably mounted in such a position that its flame is not directed into the small-diameter drum-portion II where it would interfere with the air stream created therein by the burner 3d. In other words, the flame is largely confined within the axially projected limits of the annular wall I2 so that it will impinge upon such wall rather than entering the smaller drum-portion I I. As a result, practically all of the hot products of combustion from the burner 33 and practically all of the air entering through the opening 3i passes generally upwardly through the larger-diameter drum-portion IIl to enter the exhaust opening 36 without traversing any portion of the small drum-portion II.

At each revolution of the drum, some of the aggregate discharged by the flights 2I will fall into the small-diameter drum-portion, either directly or after interception, by the scoop 25 and -will work under the influence of gravity through the small drum-portion II. As it passes downwardly through such smaller drum-portion II, the aggregate will be repeatedly lifted and dropped through the stream of air resulting from the presence of the burner 34.

The size and proportions of the drier 4will depend upon its desired capacity and upon the amount of moisture which it is desired to remove from the material being dried. Ordinarily, the chamber defined by the annular side wall of the larger-diameter drum-portion I8 and by the end wall I2 will have a diameter materially greater axial extent. The smaller-diameter drum-portion II desirably has a length equal to at least twice its diameter, and is preferably even longer. The diameter of the larger drum-portion III is such that it extends downwardly beyond the point at which it is convenient to load aggregate into it, and it is thus possible to have the drum-axis slope downwardly from the inlet end of the drum to the discharge and Without the necessity of providing means for elevating aggregate into the discharge end.

In my drier, the wet aggregate entering the larger drum-portion cornes into immediate contact with the heated air which enters the opening SI. Such air, coming directly from the burner 33, is both hotter and drier than it would be if it had previously been in contact with incompletely dried aggregate. Further, such air passes 4 rapidly through the drum-portion I0, as its general path is almost directly upward. As a result of these facts, the removal of moisture from the aggregate within the drum-portion I0 tends to induce air-flow axially through the smallerdiameter drum-portion I I, and thus increases the rate of air-ow and the drying action occurring in such drumportion I I. In some instances, as where the aggregate is not too wet and it is desired that its temperature at discharge be not too high, the burner 34 at the discharge end of Vthe drier may be eliminated. In such a case,

there will be an induced flow of relatively cool air through the small-diameter drum-portion I0, and the aggregate therein will be both cooled and further dried.

I claim as my invention:

l. A drier for aggregate and the like, comprising a drum having intercommunicating portions of materially different diameter interconnected by an annular wall, means rotatably supporting said drum with its axis sloping downwardly from the portion of larger diameter, means for rotating the drum about its axis, a stationary plate closing the open end of the larger-diameter drum-portion, said plate being provided in its lower portion with openings fory the admission of air and aggregate and in its upper portion with an air-outlet opening, means for supplying a stream of heated air through said air admission opening toward said annular wall, means for directing a second stream of heated air into the lower end of the smaller drum-portion, and flights on the interior of both drum-portions for elevating aggregate and causing it to fall through said air-streams as the drum is rotated.

1 2. A drier for aggregate and the like, comprising a irst circumferentially continuous drum portion, axially spaced end walls therefor, a second circumferentially continuous drum-portion coaxial with said rst drum portion, said second drum portion being of materially smaller diam- .Yeter than said irst portion and extending axially therefrom, means supporting said drum portions for rotation about an axis inclined downwardly .from the large drum portion to the small drum portion, the lower of said end walls having a central opening providing-communication between the two drum-portions, means for directing a stream of heated air into the lower part of said larger drum portion and toward the lower end wall beyond the periphery of said opening therein, the upper end Wall substantially closing the upper end of the first drum portion and being provided with an aggregate-admitting opening and in its upper portion with an air-escape opening, means for directing a second stream of heated air into the lower end of the smaller drum-portion, means for rotating the drum portions about their common axis, and nights on the interior of both drum-portions for elevating and releasing aggregate.

3. A drier for aggregate and the like, comprising a first circumferentially continuous drum portion, axially spaced end Walls therefor, a second circumferentially continuous drum-portion coaxial with said rst drum portion, said second drum portion being of materially smaller diameter than said first portion and extending axially therefrom, means supporting said drum portions for rotation about an axis inclined downwardly from the large drum portion to the small drum portion, the lower of said end walls having a central opening providing communication between the two drum-portions, means for directing a stream of heated air into the lower part of said larger drum portion and toward the lower end wall beyond the periphery of said opening therein, the upper end wallf substantially closing the upper end of the first drum portion and being provided with an aggregate-admitting opening and in its upper portion kwith an air-escape opening, means for rotatingy the drum portions about their common axis, and nights on the interior of both drurn-portions for elevating and releasing aggregate.

4. The invention set forth in claim 3 with the addition of a scoop extending circumferentially of the lower drum-portion and projecting therefrom into the upper drum-portion to intercept and direct into the lower drum-portion aggregate released by the ights in the upper drumportion, said scoop being adjustable axially of the drum to vary the extent to which it projects into the upper portion thereof.

5. The invention set forth in claim 3 with the addition of a scoop extending oircumferentially of the lower drum-portion and projecting therefrom into the upper drum-portion to intercept and direct into the lower drum-portion aggregate released by the flights in the upper drum-portion.

6. The invention set forth in claim 1 with the addition of a vertical stack connected to said air-outlet opening, and means associated with said stack for inducing an upward flow of air therethrough.

7. The invention set forth in claim 1 with the addition of a vertical stack connected to said air-outlet opening.

8. In a drier for aggregate and the like, a rotatable drum disposed on an inclined axis and having an annular side wall, axially spaced end walls defining in co-operation with said side wall a drying chamber having a diameter greater than its axial extent, said side wall being provided interiorly with nights for elevating and dropping aggregate as the drum rotates, the lower of said end walls being rigid with the drum and provided with a central opening through which some of the aggregate dropped from said flights may escape. the upper of said end walls being stationary and being provided in its lower portion with an aggregate-admitting opening, said upper end wall also being provided with air-admission and air-outlet openingsyand means for supplying heated air to said chamber through said air-admission opening, said air-admission opening being located in the lower portion and said air-outlet opening in" the upper portion of said upper end wall whereby heated air will flow generally upwardly and diametrically through the drying chamber counter to the movement of aggregate dropped from said flights.

KENNETH E. MCCONNAUGHAY.

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

UNITED STATES PATENTS Number Name Date Re. 3,742 Jasper Nov. 23, 1869 1,102,662 Hobbs July 7, 1914 1,187,959 Ash June 20, 1916 1,422,039 Dean July 4, 1922 1,720,786 Fasting July 16, 1929 1,961,314 Wall June 5, 1934 1,964,344 Fasting June 26, 1934 1,992,705 Lellep Feb. 26, 1935 2,069,164 Vogel-Jorgensen Jan. 26, 1937 2,082,970 Overman June 8, 1937 2,290,765 Overman July 21. 1942 rFOREIGN PATENTS Number Country Date 440,349 Great Britain Dec. 27, 1935 OTHER. REFERENCES Hawkins Mechanical Dictionary, published by Theodore Audel and Co., New York, 1909, page 32.

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