US2309810A - Method of and apparatus for treating material - Google Patents

Description

Feb. 2, 1943. L. B. WEST 2,309,810

METHOD OF AND APPARATUS FOR TREATINGMATERIAL Filed 0st. 50, 1941 2 Sheets-Sheet 1 I (fin-nay V Feb. 2, 1943. 4

METHOD OF AND APPARATUS FOR TREATI ENG MATERIAL Filed Oct. 50, 1941 2 Sheets-Sfieet 2 T0 EXHAUST FAN DUST PARTICLES Il/l/l/I/ll/ I II ///////////4 I r1 1 I! II Patented Feb. 1943' METHOD or FOR TREATING MATERIAL r Lawrence B. west, ci namon, rem. Application October 30,1941, Serial No. 417,193

- 24 Claims.

This inventiontrelates" to the drying of eral aggregate or like material under variable heat conditions, and a process therefor, which will be more efficient .and less costly to operate than those heretofore proposed. g Referring to, the accompanying drawings forminga part of thisspecification and in which like partsare designated-by like numerals+ Fig. 11s a vertical longitudinal sectionalview .of an apparatus made in accordance with this invention; I Fig. 2 15 a transverse sectional view taken as on the line 2-2.of Fig. 1 and looking in the direction of the arrows;

Fig. 3 is atransverse sectional view takerras onthe line 3-3 of Fig. l and looking lathe direction of the arrows; 1 A

' Fig. 4 is a transverse "sectional view taken-as on the line 3 & of Fig. 1 and .looking in the direction, of the arrows; and v as well asan exhaust means for the gases utilized. v This invention constitutes an improvement over that disclosed in 11.8. Letters Patent No. 1,641,108 granted August 30, 1927, to Lawrence B.',West and entitled Apparatus for drying and heating material, and No. 1,871,934 granted August 16, 1932, toLawrenceB. West and Marion P. Wallentitled Process of and apparatusfor drying material, both patents disclosingtherein a double-shell drier. r Intheart of. drying mineral aggregates for asphalt paving and other purposes, it is a well known fact .that somecharacters of aggregate material, especially those having a large clay content, will dry better in a single-shelldrier, whereas other materials willdry more readily,

and especially more economically, in a double 'shell drier. Therefore, a combination of a double-shell and a single-shell drier in accordance with this disclosure will meet all of the requirements in the drying of all kinds of mineral aggregate, thereby lowering the initialiand operating costs.

Further, this combinationfoi driers will pea niitithe feeding of onekind or grade oilaesra ,eatifnaterialin 'onneend ft el'arn r m a another-kind orgracle into the opposite end oi theiapparatus, the two kinds ,oi a gregate.

being conveycd'in streams of opposite directional I flow within the app one kind wiir-j mixture of the" two" an area where the iiih'er kind, the ereaiterbeing con! veyed, in a stream disposed within one of the first mentioned streams, to the discharge end the material, hot gases and/or cooling air iar 5 passed over the materialto'obtainthe desired results, this invention'thereby lending itself admirably to either the production of hot-mixed or cold-mixed asphalt. f

It is also ade'cided advantagefin drying" min- 1 eral aggregates, in the operation of an asphalt plant, to'beable to operate economically" at a lower capacity. and also to operate at anextremely high capacity. When a low'capacity is desired the materialis fed only into one end of the apparatus, but by feeding the material intoboth'en the apparatus will be operating at 100% capacity, I v g I Y Referring to the 'drawings' a stationary iur nace '2 is indicatedattached to the breeching 3 I gay. andprovidedwitlia source of heat such as an Fig. 5 is a diagrammatic representation of a feeding means for the material being treated,

cylindrical casing orfdrum fij'secured thereto as by the obl que partitions "l, as was the case distclosed in said patentsf'ljheouter drum 5 posed between thebreeching 3 and a, similar brefeching fiat opposite ends of the'drum, sealing rings such as 9 being providedffor preventing any material loss ofhot'gas'esto the atmosphere, the sealing rings cooperating with-annular rings or collars such as I!) carried by the breaching and providing means for'the passage of material and gases betweenthe breeching and said The inner end'jof'the 'innerdrum o is disposed at approximately the middle of the outer drum, but, the "opposite 'erido f 't'he inner drum extends beyond the end of the outer druinand through the breechingfi. The extending end of the inner i0 drum carries external'screws' such as it bymeans of whioh material is. forcedfrom the lower region of said breaching into ,the I compartments j l2 termed by, the partitions l between the inner and outer drums, such material being ied in'to the breeching through-the aperture iii therein by any suitarile meanssuch as a conveyor it.

, 'Inclined'fiightssuch as km the'partitions 'i' move the materialprogrejssivelytoward the inner end or the izmer drum, and flights su'chas' it so within each compartment" cause" the material'to Ice-cascaded orshowered across the compartments so as to come into more intimateconta'ct I with the'liot drying gases; during the rotation oithe apparatus. when the material reaches Blithe. inner end of said compartments it drops of the apparatus. During such conveyance. of

through valves or openings formedin the wall of the inner'drum and is. started by the inclined flights l8 in a reverse directional movement within the inner drum toward the discharge chute IS, a great plurality of buckets'.or cups 20 attached to the inner surface of the-inner dmm assisting in this reverse movement and causing a cross-shower of the material within the inner drum as clearly indicated in Fig. 2. Therefore it will be understood from the description so far that material fed into the breeching 3 is caused to move to the right as seen in Fig. 1 within the compartments l2 by the flights l5, but after reaching the valves I! of the inner drum, the

7 material passes through said valves and is caused by the buckets 20"to be moved within the inner drum to the leftas seen in said Fig. 1.

, Hot gases created by the burner 4 are caused by a suitable exhaust fan to travel from the furnace 2 through the inner drum to the extreme inner end thereof, and thence in the opposite direction through the compartments |2, between the inner and outer drums, to the breeching 3 and out through the flue 2| to a dust} collector or classifier 22, and thence to atmosphere through the exhaust fan, any dust particles carried by the gas flow being caught or trapped'in g the collector-22 and'rec'overed from the discharge 23 thereof, a suitable valve 24 beingprovided in the flue 2| to regulate the amount of airand gas passing through the device.

Up to this point the apparatus is substantially a duplicate of that disclosed in said patents.

The end of the outer drum adjacent the breeching 8, carries a cone such as 3|! axially thereof, which cone is so directed as to positively impel material into the drum, saidcone secured to the drum as by the spacing plates 3| for rotation with the drum. The wall of the breeching at the juncture with the drum-is suitablycut away in order that the material admitted through the opening 32- (as bya duplicate of the conveyor 4) may reach the interior of said drum where the material is picked up by the plurality of buckets or cups suchflas 33 and moved to theleft as seen in Fig. 1, tol'meet-the material travelling in the reverse'j'direction through the compartments l2. v

'wall of the breeching 8 is cut away in substan- The opposite tial registry with the end of the bone 33, and covering this cut-away portion of said wall is a seebreeching} .(and a substantial duplicate of flue 2|) and by providing the damper 39 therein, the

entire apparatus is made adaptable for various uses. In other words either or both of the-furnaces may be used to generate the hot gas. For example, with burner 36 lighted and valve 3! closed, the current of hot gas will flow from furnace 34 through the drier to and through the flue 2| thereby heatingthe material in either.

or both the compartments 31 and i2, in which case it may be found desirable to open unlighted furnace 2 so that cooling air may be drawn therethrough and through the inner drum 3 to mix with the hot gases in compartments II. On the other hand the burner 4 may be used alone for the source of hot gas which is extracted through flue 2| and/ or 33 as-desired. Still further burner 4 may be utilized as the source of hot gas, and unlighted furnace 34 opened and valve 33' closed, whereby cooling air will be drawnthrough. the furnace 34 and chamber 31 to mix with the hot gas escaping'from the apparatus through compartments l2 and flue 2|.

From the foregoing description it will be seen that by this invention there is provided a combination single-shell and double-shell drier which meetsall the conditions and requirements that may be encountered in drying mineral aggregates,- especially for asphalt road-building purposes, and which combines the advantages of both types of drier into a dual drier at a saving in initial and operating costs. Most materials dry more economically in the doubleshell drier (5 and G) such as stone, gravel, and reasonably clean sand. Other materials, such as sand with a high clay content, are difficult to process through the economical double-shell 1 drier, and therefore this apparatus has been. devised which will'process both classes of materials either singly or together, to the best advantage.

This apparatus is provided with dual means of feeding and conveying. The dimcult material, with the .clay content, should be processed through the single-shell drier from breech-lg 3,

and the other materials should be processed through the double-shell drier from breeching 3,, both classes of materials ultimately entering the inner drum 3 and reaching the discharge l3, and when both classes of materials are being processed simultaneouslyv they may be-controlled 0nd cone 34 substantially axial with the cone 30,

the smaller end of the cone (furnace) 34 communicating with a housing 35 containing a source .of.heat suchas the oil burner-33.

ing 3, and flue2|, thereby drying said material as wellas, if desired, any material admitted chamber by the buckets 33, and escape from the apparatus through the compartments l2, breechthrough breeching 3 and passing through: said compartments |2 as heretofore described. The

material from breeching 3 ultimately reaches the compartments I2 but, due-to the flights Ii therein will be forcedto and'through the valves I! of the inner drum 3 and be conveyed to the discharge I! by the buckets has heretofore described.

By providing the flue 33 connected to as to proper proportions through the conveyors N to meet the specifications of paving. Fur-- thermore, when the demand is for very large production, both'single andrdoubleeshell portions of the apparatus can be put into service to reach a maximum capacity.

shell portion of the apparatus (if the characterv of material will permit)- due to the conservation of'heat within the inner drufm by the blanket j effect of the moist or wet' material passing I through compartments |2 from breeching '3;

or to operate the single-shell-portion. of the.

apparatus for material with high clay content.

Requirements often are for asphalt ,paving mitxures whichare processed cold, using naphtha or some other temporary solvent other that heat,

the purpose .being to prolong the set ing or hardening time so that the mixture can be stored or transported over long distances, The mineral aggregates for this-cold process must' be 0n lowercapacity it is more economical to operate only the double- It will therefore be seen thatthisdual drier oflers all of the advantages of the double-shell drier disclosed in said patents, and provides the major advantage or a single-shell drier na'mely,

.sis will be given. This contemplates the use oi content to better advantage than would be attained with a double-shell drier." That is to say, the single shell drier in combination with the the processing of materials with a high clay double-shell drier produces a higher efficiency in that the capacity of the apparatus is greatly.

increased and the production cost is greatly lowered by virtue of the saving in the heat or the waste gases from the single-shell drier which are put to use in heating material passing through the compartments H of the doubleshell drier.

With respect to l hot materials processed I through the double-shell drier, the following brief "summary is given. The wet .cold sand or other mineral aggregate is fed by conveyor l4 into breeching 3 from which the screws ll pass the maerial into the compartments I21 during the rotatiomof the drier, and the flights 15 on the partitions l progressively move the material lengthwise of. said compartments until the material reaches and passes through the valves ll into the inner drum'fi, the material in compart- .escape.

' For drying and then cooling mineral aggregates for producing cold mixtures, the following synopnaptha or other light distillates instead of heat for keeping, the mixture in workable condition for longer periods of time than where asphalt is added'directly to the heated material for immediate paving purposes. In this drying and cooling process unlighted furnace 2 is opened, and

' burner 36 is lighted, wherebythe'hot gases will be ments l2 receiving a preheating direct from the hot gases passing throughsaid-compartments as well as from the heat radiated from the metalv wall of the inner drum. Within the inner drum the material is progressively moved by the buckets in the reverse direction to the furnace end of said drum and the discharge chute is, said material in this movement receiving themaximum amount of heat directly from the hot gases flowingv counter thereto, or in other words the material is superheated in its passage through the inner drum, the exhaust fan inducing flow of the hot. gases. In this process the furnace sens unlighted and closed, and valve 39 in flue 38 is closed, but valve '25 in flue 2! is open to a degree commensurate with the desired time and temperature of drying. \V p With respect to processing dimcult materials, with clay content, through the single-shell drier, the following brief summary will be given. Ma-

terial from a conveyor is conveyed into the breeching 8 andinto the single-shell chamber 31 where it is picked up, cross-showered, and progressively moved by the buckets or cups 33th) and into the inner drum t and/or the compart ments ltirom which latter the material passes through the ports l-l into said inner drumwhere the buckets 2d progressively move the material to '--these dampers being in accordance with the con-Q trol and proper distribution of the air and hot gas current desired with relation to the materials being processed. Thus it will be understood that a valuable feature of this invention resides in the fact that the material which is being processed through the single-shell chamber 311 can, by a careful adjustment of air current by damper it, be processed at a lower fuelcost than through the ordinary type single-shell drier. Also, the only partially cooled hot gases from the singleshell drier can be passed through the compartments ii of the double-shell drier, thereby utilizcaused to travel by the induced air current through the single-shell chamber 3], through the 4 compartments l2, and out through the flue 2|, cooling air being .drawn through the open unlighted furnace 2', through the inner drum 6 and mixing with the hot gases in compartments l2.

It is obvious that those skilled in the art may vary the-details of construction comprising the apparatus. as well as vary the steps of the method, without departing from the spirit of this invention, and therefore it is desired not to be limited to the exact foregoing disclosure except as may be required by the claims.

What is claimed is: a

1. A. method of treatingmaterial which comprises conveying the material in streams of opposite directional flow to an area where the material of both streams. mix' and thereaiter'conveying the mixed material in a stream disposed within one of the first mentioned streams, subjecting the material while being conveyed in the first mentioned streams to a current of hot gas, and subjecting the mixed material while being conveyed to a current of cooling air.

2. A method of treating material which com prises conveying thematerial in separate streams ;of opposite directional flow to an area where the material of both streams mix and thereafter conveying the mixed material in a stream disposed withln one of the first mentioned streams, subjecting the material while being conveyed in the first mentioned streams to a current of hot gas having uni-directional flow, and subjecting the mixed material while beingronveyed .to a current of cooling air moving counter to the flow of the mixed material.

3. A method of treating material which comprises conveying the material in streams of opposite directional flow-to an-area where the material ofbothstreams mix, one of said streams being substantially annular, and thereafter conveying the mixed material in a stream disposed within the annular one of the first mentioned streams, and subjecting thematerial while being conveyed in each of the first mentioned streams posite directional flow to an area where idle material ofbotli streams mix and thereafter con- ,veying the mixed material in a-stream disposed within one of the first-mentioned streams, sub-.

jecting the material while being conveyed in the first mentioned streams to a current of hot gas,

subjecting the mixed material "while being'con;

ing the hot gases thereln that otherwise would ,contact ing a temperature different than the temperaveyed to a current current of cooling gas substantially at the area where of cooling air, and uniting the air with the current of hot the materials 5. A method of treating material which comprises conveying the material in streams of opposite directional flow to an area where the material of both streams mix and thereafter conveying the mixed material in a stream separated from and disposed within one of the first mentioned streams, and passing a current of gas,

having a temperature different than the tema,so9,s1o

rial while moving in the first direction sub-- 'perature of the material, in contactwith the mamixed materials to a counter current of cooling 7. A method of treating material which comprises conveying two diilerent kinds of material in substantially coaxial streams of opposite directional flow, subjecting the material of both streams to a single current of hot gas, mixing the heated material of one stream with the heated material'oi the other stream, conveying the mixed materials in a stream disposed within one of the first mentioned streams, and subjecting the stream of mixed materials to a counter current of cooling air. 7

8. A method of treating material which comprises conveying two different kinds of material in streams of opposite directional flow, one of said streams being substantially cylindrical, subjecting the material of both streams to a current of hot gas. mixing the heated material of one stream with the heated material of the other stream, conveying the mixed materials in a stream disposed within the cylindrical stream, and subjectin the stream of mixed materials to a counter current of cooling air.

9. A method of treating material which comprises conveying two difierent kinds of material in separate streams of opposite directional flow,

subjecting the material of both streams to a current of hot gas, mixingthe heated material ,of one stream withthe heated material of the other stream,- conveying the mixed materials in a stream disposed within but separated from one of the firstmentioned streams, and subjecting tioned streams, and subjecting the stream .of

jected to a current or hot gas, and said material while moving in the other direction subjected to a current of cooling air, the currents of gas and air being counter to the flow of material, and the current of gas passing through the area of change of ,directional flow of the material, con- "veying material of a different kind in the said reverse direct on and mixing it with the first mentioned ma rial while subjected to the current of cooling air, and subjecting the material of the difierent kind to the current of hot-gas prior to its mixture with the other material.

12. A method of treating. material which comprises conveying material of one kind in 9. cy-

lindrical stream in one direction and then in the reverse direction within but separated from said stream, the material while moving in the first direction subjected to a current of hot gas, and said material while moving in the other direction subjected to a current of cooling air, the currents of gas and air being counter to the flow of material, and the currents of gas and air mixing together and passing through the area 01 change of directionalfiow of the material, conveying material of, a'difierent kind in the said .reverse direction and mixing it with the first mentioned material while subjected to the current of cooling air, and subjecting .the material of the different kind to the current of hot gas prior to its mixture with the other material.

13. A method of treating material which comprises conveying material of one kind in a cylindrical, stream in one direction) and then in the reverse direction within said stream, the

unaterial while moving in the first direction subthe stream of mixed materials to a counter current of cooling air.

10. A method of treating material which comprises conveying two different kinds of material in streams of opposite directional new, processing the material of both streams by passing in ture of the material, mixing the processedmaterial of one tream 1l.- A method of treating material which com- 1 one kind in a cythen in the the mate,-.

with-the material a current of gas havspaced therein;

jected to a current of hot gas, and said material while moving in the other direction subjected to a current of cooling air, the currents of gas and air being counter to the flow of material, and

the currentof gas passing through the area of.

change of directional flow of the material, conveying material of a diflerent kind in the said reverse direction and mixing it with the first mentioned material at the area of change of directional flow of the latter, and subjecting the material of the difierent kind to the current of hot gas prior to its mixture with the other. material.

14. In an apparatus of the character described the combination of an outer drier casing; a

superheater extending from approximately the middle to beyond the end of said casing and space be'tween said superheater and said casing;

means to feed material into each end of said V casing; means, extending from each said feeding means to said space, to convey material from both ends of said casingflto the space between said superheater andgsaid casing; means to convey the material to the interior of said superheater from said space, for mixing in said superheater; medns to deliver the mixed material from said superheater; and means to rotate said superheater andsaid casing.

15. In an apparatus of the character described the combination of an outercasing; an inner casing extending from approximately the middle to beyond the end of said outer casing and a stationary breeching disposed about the extending end 01' said inner casing andcoinniunicating-with the space between said a flue adapted to admit hot gas inner and outer casings; means to feed materialinto each end of the outer casing; extending from each said feeding means space, to conveymaterial from both ends of said outer casing to the space between said inner and outerjcasings; means to convey the material to the interior of said inner casing from said space;

16. In an apparatus of the character described the combination of an outer drier casing; a

means, 3 to said superheater extending from approximately the middle to beyond the end of said casing and spaced therein; a flue adapted to admit hot gas to one end of the superheater; a stationary breeching disposed about the extending end of said superhea'ter and communicating with the space between said superheater and said casing; meansto feed material into'each end of said casing; means comprising spaced elements carried by said casing and extending from each said feeding means to said space, to convey material from both ends of said casing to the space between said superheater and said casing; means disposed'at the inner end of said superheater to convey the material to the interior of said superheater from said space, for mixing in said superhater; means to deliver the ,mixed material from said superheater; and means to rotate said superheater and said casing. u

17. In an apparatus of the character described the combination of an outer casing; an inner casing extending from approximately the middle to beyond the end of said outer casing and spaced therein; a stationary breeching disposed about the extending end of said inner casing and communicating with the space between said inner and outer casings; means to feed material into each end of the outer casing; means com- ,prising spaced elements carried by said outer casing and extending from each said feeding means to {said space, to convey material from both ends of said outer casing to the space between said inner and outer casings; means disposed at the inner end of said inner casing to convey the material to the interior of said inner casing from said space, for mixing in said inner casing; means to deliver the mixed material from said inner casing; means to rotate said inner and "outer casings; and means to pass a current of gas, having a temperature different than the temperature of the material, in contact with the materials while so conveyed."

18. A rotating mixer comprising inner and outer drums spaced by a plurality of partitions providing passageways between the drums, the inner drumextending from one end to approximately the middle of the outer drum; means to convey material from' both ends of the outer drum to the innermost ends of said passageways where the conveyed materials unite; means to deliver the united materials to within the inner drum; means to mix the united materials in the inner drum and to convey the mixed mate rials tothe outermost end of said inner drum; and means to pass a current of gas, having a temperature difierent than the temperature of the material, in contact with the materials while so conveyed.

19. A rotating mixer comprising inner and drum. v

20. In a drier of the character described the outer drums spaced by a splurality of partitions providing passageways between the drums, the

inner drum extending from one end to approxi mately the middle of the outer drum; means to feed material into each end of the outer drum; means, extending from each said feeding means to said pasageways, to convey material from both ends of the outer drum to the innermost ends of said passageways where the conveyed materials unite; means to deliver the united materials to within the inner drum; means to mix the united materials in the inner drum and to convey the mixed materials to the outermost end of said'inner drum; and means for processing the materials with a current of gas having a temperature diflerent than the temperature of the materials being coliveyed, said processing means comprising an exhaust flue, as well as a controllable source of gas,

communicating .with each end of said outer combination of two concentrically spaced cylindrical drums, one drum extending inwardly from one end of the other drum to approximately the middle of the said other drum, the innermost end of the inner drum being freely open to the interior space of the outer drum, means for feeding material to be dried into each end of the drier; means to convey the material within the drier in opposing directions, from eachsaid feeding means to the space between said drums at theinnerm'ost end of the inner drum where the oppositely moving materials meet; a furnace disposed at either end of the drier for selectively' processing the material while being so conveyed; and a discharge for the processed materials. Y 21 In an apparatus; of the character describe d the combination of an outer drier casing; a

' superheater substantially concentrically spaced therein, said superheater being'substantially half as long as said casing and havingone end terminating approximately at the middle ofsaid casing; a flue adapted to admit hot gas to one.

end of the superheater; means to feedmat'erial into each end of said casing; means to convey the fed material from both ends of said casing into the space between said superheater and said, casing; means to convey the. material to r the interior of said superheater from said space.

for mixing in said superheater; and a discharge for the mixed material from said superheater. J '22, A method of treating material in a mixer which cdmprises charging materialof one kind into one end of the mixer, charging material of a diflerent kind into the opposite end of the mixer, conveying. both materials in opposed streams inwardly from the respective ends of.

the mixer to an area of meeting of said materials, conveying the united materials from said.

area to one end of the mixer for discharge there- .from, the united materials moving in a stream disposed within the stream of one of the materials, and passing a current of gas in contact with the materials while so conveyed.

23. A method of treating material which comprises conveying the material in streams of opposite directional flow to an area where the material of both streams mix, and thereafter conveying the mixed material in a stream disposed within one of the first mentioned streams,

and subjecting the material while being con-- veyed in each of the first mentioned streams to contact with a current of gas having a tempera- 24. A method oftreating material which com- Q prises conveying the material in streams of opposite directional flow to an area where thematerial of both streams mix, and thereafter conveying the mixed material in a stream disposed within one of the first mentioned streams. 10

and subjecting the material while being conveyed in each of the first mentioned streams, as

well as in the stream of mixed material. to contact with a current of gas having a temperature different than the temperature of the materiai,.the current of gas. during contact with the material being in a direction counter to the movement of each material stream.

LAWRENCE B. wns'r.

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