US2607537A - Drying - Google Patents

Description

P. A. SHAW Aug. 19, 1952 DRYING Filed. Oct. 15, 1948 2 SHEETS-SHEET l FURNACE 20 CL EANOUT 4O DAMPER CONTROLLED INLET 24 COOKED FISH MEAL FROM PRESS 7O COARSE PARTICLES FUNNEL -SHAPED DRYING CHAMBER STAR FEEDER 74' DIS IN TE GRA TOR 7/ PREHEA TED F/SHMEAL 8 GAS TO DRYER emu/v0 LEVEL FIG. 3.

VERTICAL VANES INVEN TOR. PAUL A. SHAW TELESCOPE PIPE FURNACE CHE CKER WORK WALL AT TORNEY Aug. 19, 1952 s w 1 2,607,537

DRYING Filed 0012- 15, 1948 SHEETS-SHEET 2 C ONNE C T/ON 70 CENTRAL SUCT/ON PIPE 60;

' INVENTOR. PAUL A. SHAW AT TORNEV Patented Aug. 19, 1952 UNITED STATES PATENT OFFICE},

DRYIN G Paul A. Shaw, Wilmington, Calif., assignor to Terminal Island Sea Foods, Ltd., Terminal Island, Calif., a corporation of California Application October 15, 1948; SerialNo. 54,616

13 Claims. 1 ilns invention relates to drying, and particularly to the drying of heterogeneous finely divided material of low average bulk density and which tends to deteriorate at high temperature. However, the apparatus of the invention may be employed advantageously in the treatment of a variety of materials, including those which are homogeneous and those which can be subjected to high temperaturewithout damage.

This application is a continuation-in-part of my co-pending application Serial No. 735,511 filed March 18, 1947, now Patent No. 2,513,370.

It is common practice to dry solids by suspending them in a current of drying gas, say hot air, and many products are dried, successfully in this fashion at the present time, although thermal efllciencies are not always as high'as might be desired. In otherinstances, such drying procedures are not satisfactory, since they result in a scorching of the material being dried -or some other deterioration in quality.

Design of, structures in which low density 2. That large particles are not only heavier.

than small particles but also require a. longer time to dry;

That for any properly dried product, the particles are of uniform specific gravity.

There may be cases in which these assumptions are true, but in the case of fish meal and other materials, they are incorrect and equipment designed in accordance with themdoes not operate properly. Wet fish meal is a heterogeneous mixture of bone, muscle, scale, skin and gut particles. Particles vary with respect to size, shape, moisture content, texture and density. There is a great difference between round, dense tuna eyes and fiat, light bones, and between flufiy muscle tissue and dense leathery gut tissue. Even though the meal has been cooked, pressed and passed through a disintegrating mill, its constituents do not lose their identity and'variations such as those noted above continue to exist. Both Dlant experience and laboratory tests show that many undried particles of fish meal are lighter and more buoyant in air than other completely dried particles.

stream. Processes or apparatus which classify So. although each in-. dividual particle of fish meal tends to lighten on- "2 material particles on the basis of density either in the drying .gas current, or subsequently in an operationfrom which the more dense particlesv are returned for additional drying, are not optipractical andefiicient means for low temperature drying of fish meal or the like while it is suspended in a gas current, say .warm air. The scorching of protein, the odor nuisance, the smo production, the vitamin loss and the lowered feeding value which occur in the drying of fish meal in conventional dryers (including not only the' air current types but also direct fired or steam tube rotary driers) are avoided in the practice of the. invention. Moreover, the apparatus of the invention is compact, and has extremely high throughput in terms of space occupied. In it the buoyancy and the carrying power of the stream of drying gas are maintained while an adequate lag between particle speed and gas speed is induced to permit proper drying in relatively small space.

The apparatus of the invention in its simplest form comprises a tower having a chamber, the

cross section of which increases with height. An

inverted frusto-com'cal chamber is preferred, but one of inverted frusto-pyramidal shape may also be employed. A conduit, preferably disposed vertically, opens into the small bottom portion of the chamber. A current of drying gas is forced up through the conduit and the chamber, either by pressure, from below or suction from above. The material to be'dried. say fish meal or peat moss, is introduced into the conduit and carried upward into the funnel-shaped chamber by the as current, where it fountains outward with the increasing cross section and decreased velocity, thereby partially losing its buoyancy. The inlet section velocity and cone dimensions are so arranged that a portion of both the heavy and light ,solid particles will be carried to the full.

cone height with considerable remaining velocity. At a relatively high point, say near the top of the flared chamber, a swirling motion is imparted to the gas stream by-means of a stationary bafile having radial vanesv which may be .made adjustablewith respect to the angle which they make with the horizontal. Solid particles-within the gas stream'tend to resist this sudden change of gas direction, strike the baflle and are deflected downward to be again buoyed up by higher velocitiesin the lower cone area. Some particles, both heavy and'light, will, of course, remain in the gas stream and be c'arriedupward in a spiral motion.

matter passing through, the oblique baffles is equal to that'being fed. Once having passed the bafile, the spiral motion will continue to carry the heavy and light, large and small, particles :lower portion of an alternative form of dryer of upward and-out, say through a fan to a cyclone separator.

The angle of the bafile adjustment together" with the total air volume determines theequ'i librium load and therefore the drying time;

Oddly enough, the holding time is reduced byv moving the bafiies toward a horizontal position,

i. e. the holding time of material in the dryeris 4 greater when the baffles are set at 35 from the horizontal than. when they areset at 10.9...from the horizontal. :This is due..to-.increas'ed gas.

velocity at the lower angle which permits a higher percentage of entrainedsolid particles to continue upward with the gas ratherithan being deflected downward'. The .total gasvolumeand bafile angle :may therefore; be. .adjustedso as to establish optimum..conditions for the particular...

material beingdried. .1

- If desired, the=apparatus. may'.have .a plurality.

of radiallyvaned baffles superposed one above the other, the vanes. ofsuccessive bafiles. maybe them; if a plurality. isemployed, may be. adjusted to suit the particular materiaLto be. dried.

It -is'de'sirable to-avoid. turbulence-an swirling in the funnel-shaped chamber exceptgimmediately below A the .first or lowest: bafiie, .since 'it has been determinedexperimentally that an abrupt-change of gas direction and asudden: beginning: of swirl ing-action is desirable. 1 With this in mind, I-pre fer:-to.;provide platesin thelower conduit, or-in the funnel-eshaped chamber or both to direct the gas upward and top-revent turbulence or swirling in the conduit and i'nsth'e lower-portion ofthe-funnel-shaped chamber. i

lit-order to facilitatethe -swirling induced by the radially vaned bar-lies. in the upper-portionof the d ryer, I prefer to withdraw the gas from-thespacezabovethe baffles: through a tangential pipe.

In the preferred design, the tangential pipe is connected to sucti'on f an, -which exhausts to a cyclone collector orthe like in which the'bulk of the driedproduct is collected. 1 1 1 Another.extremely desirable feature which may beincorporatedin the dryer of the invention isa pipewhich is connected-seine dryer outlet, for

examplain or just ahead of the suction fan and drops 'down throughf the conduit'below the funnel-shapedahamber. Friction of gas against the inlet conduit walls creates a lowered velocity-adjacent to-the shell and vsomeparticles. principally I the heaviest ones, which have been deflected downward to the cone wall will continue down- Ward close to theshellxand collect in theibo'ttom hopper. The small: diameter pipe with considerably ghigher gas velocities; serves to re-zentrain' these-particles, now drypand transportthem to thefan; Withsome prcductsit isdesirable to end.

4 this pipe above or below the'adjustable cone bafile rather than at the fan inlet.

The foregoing and other aspects of the invention are explained in detail with reference to the accompanying drawings in which:

Fig. 1 is a diagrammatic vertical elevation, partly in section, of a drying plant designed in accordance with the inventionp'articularly for the drying'of fish meal;

Fig. 2 is a plan view of the apparatus of Fig 1;

Fig. 3 is a fragmentary vertical section of the the invention;

Fig. 4 is an elevation of the vertical conduit at the bottom of the dryer of Figs. 1 and 2;

Fig. 5 is a plan View of the conduit of Fig, 4 showing the arrangement of the interior plates provided to streamline the gas and prevent turbulence; Y

Fig. 6 is a vertical elevation of the funnelshaped drying. chamber of the apparatusof Figs.

1 and2;

Fig. "7 is a' planview of thedrying chamber of Fig 6 showing the arrangement of a spider ofplates providedto prevent turbulence of gas in thecharnber until thevaned baille at the top of the chamber is reached;

Fig. 8 is an elevationoi'a cylindrical chamber in the apparatus of Figs. 1 and 2 above the funnelshaped chamber and containing the'first of two transverse baffies withradial vanes;

Fig. 9 is aplan view of the chamber of Fig.8 showing details of the transverse baflie referred to in connectionwithFig. 8;

Fig. i 10 is an elevation ofsa: cylindrical chamber bulk density and high'moisture content, such asv sewage-sludge, peat moss, etc. Heat for theoperation is suppli'ed 'by a conventional furnace orfire box 20. furnace pass .into'an exit fiue 22 which rises-vertically and then drops down toa communicating hopperi23;. Colda'irin controlled amount is introducedfinto the bottom of the flue through a dampei controlled inlet 25. I 1

Thejd-ryer proper isdisposedabove the hopper.

lthagx-a lower vertical cylindrical pipe section 25which'opens into a .verticalupwardly flaring frustot-conical chamber 2B; this funnel-shaped chamber-opens into an upright cylindrical chamber -zl 'd isposed directly above it and having thesainediameter asthe upper portion'ofthe cone. -A horizontal pipe 2 8 projects tangentially from the upper portion of thecylinderand serves'as a connection betweeen the. cylinder and the suction side of a powerdriven fan'29, the outlet i-lil-of which is connected touaconventional cyclone-"collector 3| In many" instancesithe chamber 27 -rnay-only be of sufiicient: height above the cone to providefor the tangent outlet-28, since practically all drying occurs-below the cone bafile- Vertical vanes32 in-thefo-rm of a grid are dis posed inlth'e lowe'r or inlet pipe 25" of the dryer. The :material to be-dried', say fish-meal, 'is fed The hot gases of combustionfrom the" The upper end of continuously intothe pipe 25 bya screwfeeder 33 disposed just abovethese vanes. In the frusto-conical'; or funnel-shaped cham-.

ber of the dryer there is another set of vertical vanes 34 arranged to streamline the gas anisolid flow through the lower portion of this chamber so as to present a vertically rising stream abrupt 1y to the action of. a first transverse, bafileifi (see Figs. 8 and 9) disposed at or slightly above thelevel wherethe funnelrsha'ped chamberv joins the upper cylindrical chamber. A second bafile 31 (see Figs. and'lD'haVing radial-vanes is disposed in the upper cylindrical chamber about two-.thirdsof: the way .up, Sor, just below the tangential outlet pipe-.---=If"the upper chamber is short the second baffle- .31 may be dispensedwith.

.A concentric vertical pipe 38 of relatively small diameter extends from a point near the bottom of the hopper upward throughthe' various .superimposed sections of the dryer and is connected at itsupper end to the suction pipe 28 which forms theinlettothefan; v u- The flue and hopper construction shownin Figs. 1 and 2 is: preferred for a number of reasons. The cold air entering the flu'euat itsbot tom. adjacent the furnace'protects thewall 39 between the two portions of the fine, from the directaction of the hot gases, and-thej-sharp bendat the top of the flue. assures proper, mixing ofthe furnace gases and the cold air which is drawn in through the dampers. Consequently,- the surfaces in the hopper etc. which, may come incontact with the material to be dried do not become hot enough to cause scorchingofmate- 'rial which may come in contact with .or-itlodge upon them. Second, the flue and hopper structure is such that it can all be builtabove ground level, permitting easy access to the bottom of the hopper for cleaning, etc. The bottom of the hopperv is provided with a cleanout door 40 which is opened periodicallyto permit tramp iron and other very heavy material present in the feed to be withdrawn into a wheelbarrow, car, or the like (not shown). If desired, an opening of relatively small crosssectiori maybe provided in the hopper bottom for continuous discharge of heavy material. v I

, The'vertical vanes in the lower pipesection of the dryer of Figs. 1 and 2 arebest seenin'Fig's. 4 and 5L The vanes comprise radial plates 4! ex tendingffrom the interior suction pipe to the outside wall of the cylinder, and held together by concentric ring plates 42, the arrangement being such that a number of openings 43 of roughly equal cross section are provided. The 'eifect of the, vanes, which are, located in the bottom of the 'pipewith their major surfaces vertical, is to reduce turbulence caused by the change'ofgas direction etc. in the flue and hopper. t

The vertical vanes 34 .in the funnel-shaped chamber of the dryer are best seen in Fig'sifi and 7. They are simply radial plates 44 which extend'from the central pipe to the wallet the cone withtheir lower edges about half-'wayup the cone. They can be constructed as aninte'gral "splder unit and simply set into the cone; Their function is to keepthe stream of gas and suspended solids rising vertically, without substantial swirling, until the first transverse baflle is reached. I

This transverse baffle' 36 is shown indetail in Figs. 8 and9. It comprises eight segments 45, each of which is rotatable on a radial axis extendingfrom a'hub46 out throughthe shell of the dryer. A nut 41 on the outside-is threaded to this. shaft parallel'to the'majjOr-surface of the vane- It serv storotat th van and to. nd ea the; an e ;it mak -w th t e .ho nta1 -Whe all the vanes are horizontal, they substantially l se .the. dryer. cross s c n; but in ope ation they aresetas:;louvres at j approximately equal angles. The anglewith thehorizontal may range. from -10...-to*a1m t 90.."- ..*'.1he ave ag tim hat material is, heldin the dryer :is adjusted by;, adlusting. the angle f t e radia ba l s-axe not d above, the holding timei reduced ;by;m0v, 1. the baffles toward a horizontal position,. i. e. the holding time of material in the dryer is greater when the baflies are. set at 35.from the horiaontalthan when they are set at 10 f rom the horizontal.

The upper transverse jbaflie.; 3'|;isbest seenin Figs..10 and 11. .,-It has-sixeradial. vanes 50 gacupying .about{ three; quarters-of the cross section. Thev other-quarter isclosed by, a floor plate 5| which underlies the tangentialofitake pipe; 2-3. Crdinarily, the vanes need net be adjustable and are .simply bent pieshaped plates fastened; at

onev edge to radial spokes 52;.Which extendfrom a central hub to the shell of the dryer. In some cases,.the 1upp er transverse-baflie maybe eliminated. I Inthose casesin which i1) is employed its vanes vmaybeso set, that it tends toreverse the direction of swirling imparted by the lowertranse verse baffle, or vice versa, .As shown in,Figs -10 and 11, the .structurepreferably. isysuch that if the gas stream swirls counter-clockwise. as'a re;- sult of passage throughthe lower baflie it should be. made 20 swirl counter-clockwise through the up ri ey f The cone angle is not criticaLbut generally speaking, the heavier is the materialto bedried the steeper the cone. wa ls. should be. For fish meal,v the wallangle shown in Figs. 1 and 6 is aboutloptimum. f I. p g A. dryerllike that just described and of relatively large size has been operatedcontinuously to remove moisture frdrhffishmeal. It has a total height of about 2 5 feet and the funnel-shaped portionof the dryer is- 7 feet high and '6 feet; vin diameter atthe top. The; fan is driven by'a lO motor.

. .'Ihe temperature of thejgases entering the bot} tom of, the dryer is low, ranging from. 200 .to

300 F. The fish meal is heated to a. maximum temperature ranging from to l25 F. ;At these low temperatures the meal does not scorch or give off objectionable odors or fumes.

Tuna, mackerel and'sardine meal'have been dried in the equipment with excellent results from the standpointof character ofproduct and thermalefliciency; -In all cases the dried meal is light and flufiy andof -much lighter colorthan that produced in conventional dr ers. Moreover,

the dried meal has a higher feedingvalue than volumeof airupwardly through the mass of meal in. the binu This allows oxidation of fatzinv the meal to be substantially completed prior to pack.-

aging-so that the heat'otoxidauon-isnotavaiiable'='to. injure theproduct do rfg s't ag "Inoperating the-drier 6f desirable to"- have a '2 -pen temperature recorder and eontrol-ler,=one tor recording-the:inlet-tern of the mixd -ai'r arrd': furnace 'ga's'-, the pen recording-and controlling; the-"finish temperature by aibulb placed i-n 'th: equipment ,be'ytan'dLthe drsomecon {Suitable-gauges to indioate'suetion, -i-.-e. at the ho per-am fan intake are recommended,together with eithera variable speed drive-onthesenor-editable.iouvres toxaon-z trel the' total air1 yolume:

emperadoaor the dryer of Fi'gs. 21 and 2 is Hows: I g a 'ewar measeonnsting ore mixture -o'f rcom hustien'gases 'fromthe furnaee and the bled-4n air meets the introduced feed and tends-*to icarry invention it is the wet'particlesthereof up into the -tunnel for cone or the dryer. iilust belowth'eiirst trans= and s'uspended 'sol-ids su'fiers an abruptvchange of direction; Many of'the particle's strikeitheibatfie and-are bounceafimownward intoithe -lower:por-

tion "of the cone whe're veloci'tie's are higher: and

The central pipe-is conneeted directl-y to the fan by connector- "(see Eigs. 10 flrfd 11'). A high suctione ii's'tsattirelower en'd df the'pipe suilie'ienti-to'entrain' the heavy particles ander-aw them -sword through the central pipe theran, where they 'j oin "the particles drawn up through the outerportionof the drier; 1 ram-p iron and other ==im purities-=-which are tO'o heavy to be 'l iftefby --even the high" si'iiitiirl of, the center pipe collect in the bottomor the "the preheating a-idsdisintegration "and yields a iiuffier final product.

'In' the-apparatus of Fig. 3 'hot 'fu'rnace gase's' pa'ss' 'through a checker wors -wan; "veneereer the furna'ee into a 'down draft flue 15 cold' air to dil-iite thefurnace 'gasesl being dramin through 'a-"iia mp ered openin 5-5 the Rio-D 6f -the::flue.

'rhe lower'e'nd of the hue opens into-a pwis into iyh-ieh the cemm-rpipesor the drying QOIUm II- pTOf jects. This pipe has-=a-telescoped end section- 17 Whih sl-ides "overthe rester the pipe and-may be set 1 at various levels; so as to adjust the degree or suctior'rat'th bottom or the pit. -'etc;,=Which is-too*heaVyto be suekea up hpit, whieh is clea n'ed' out-perioeieauy;:sayettimes Ofi'ShiIbi F down-:-

The rest for: the apparatus'iofil iggiiris :sulostem-v .iOrdinarily 'the' fish' mealifromrthe. cyclone :collector is subjected to grinding prior to sacking. Increased thermal :efiic-ienbyiforcthefish :meal .dnying operation :may .bgabbtained byv-ericlosing the igrin'der ;(n'ot =shown and "passing the-warm exhaust vgases zfrom tthe cycloner exhaust'through themgrinder inclosurerandzthenee'to i-a smaller? invention. Thus the central pipeWhichis em-' ployed todraw I up the heaviest particles by means or higher suctiom m'ay be disposed outside-the-shell of the-drying tower. This however; complicates the desi'gh-and: is ordinarily not to be desired. V J :Ahumb'ermf the dryer units maybe connected either -inseri'es'or in parallelw V .To' summarize, .the dryer of the V invention is particularly useful in dr ying' finely dividedma terials of low bulk density, and is particularly useful in :drying heterogeneous mater-ial such-as fish meal, which :includes 'vparticle's of widely difierent' density. It permits drying at very low temperatures, below those at which many conventional dryers are operative. The low dryer temperature reduces fire hazards, eliminates scorching. of combustible products and in fthe case of :fish meaLz etc ;produces animprove'd product, i lighter. Land imor'e uniform :in color, miner; and with a -higher'snutritional values It can beloperated'io'n 'fish m'eal etc, without calls ingiodo'r' nuisancei'or smog serious probleins' in congested industrial areas Iaa'st1y,=-With -'-'cert'ain materials: 'i. e. peatlimos's; with .-a rr noi's'tu're con tent. of moisturegmay -b elimin ated tube having-substantially para-ll mechanically (as mist) toe-large extenh so that the evaporation "efficiency in (if-thermal input may be very}high'+""insome I cases i-n excess c ela vm v IJ'II']. a. di-ie'r, the oombiiiatioh-whih com prises -an upwardly flaringedrying --cha-mber,a "e1 walls disposed in a su-bstari't'is'ailly upri gl-it positionand' opening fm-to the bottom of the flared 'chamber, means for feeding material' to be dried int-,0 the tub ei means for passing acurrent *of drying gas upwardly through the tube'and the ehamber'with' stiffieient force to buoy u-pia'tleast*someof the material to be "dried, means ion-preventing turbulentflow of the drying gas in the tube and the. lowerpbr tion of "the flared "chamber; and "a j 'bafiie for abruptly'imparting aswirlingmotion'tdthe gas and the "material fbuoyedup'Tby it, "said bafll being disposed:in'thedrierat'a level'near the'to'p of thefiaredthamber andtrans'verse "to theup ward passage"of'thelfgas. v r "2. "In a drier;th'e combination which comprises an upwardly flaring "drying eh i'hbei', :a tube having substantially;parallel wan-5' .-disposedfih a substantially upright position and openingjint'o the bottom "of the fiaredf'chli'fibr, meansi'for feeding materialto' be -dried into the tube, means "for passing a current or 'dryingjg'as upwardly through "the tube and -.the .c-hambr -tililih?'slii'iicient'ffoi ce .to buoy-up, atlleast 'so'me'of the materialto bedried, means comprising 'vanesfdisposed iwith- .thei-r major surfaces. Ilying Iinf'th 'd-ireetiongof gas now.- in Jth' Itube i'for preventing turbulent flowoflthefldrying gasihth tubeand the lower portion-of- {the -fia;red chamber, and a bafile'for abruptly imparting a swirling-motion to the gas and the material buoyed up by ,it, said-bafile beingdisposed-in the drierat ai-le vel near--the-; top of the :fia-red chamber and trans verse-to the upward, passia e ottheigas.

3. In a i'r-rdrier, z-the: combination which com prises wan -"upWardly sharing L'drying chamber, :ia

tube having substantially parallel walls disposed in a substantially upright position and opening into the bottom vof the flared chamber, means for feeding material to be dried into the tube, means for passing a..cur rent of drying gas upwardly through the tube and the chamber with sufllcient force to buoy up at least. some of the material to be dried, means comprising radial vanes with substantially upright major surfaces disposed in the flared chamber for preventing turbulent flow of the drying gas in the lower'portion of the flared chamber, and a v multivaned baflie for abruptly imparting a swirling motion to the gas and the material buoyed up by it, said. baiile being disposed in the drier at a level'nea'rfl the top of the fflared chamber and transverse tothe upwardpassage of the gas. I

4. In a drier, the combination which'fcomprises an upwardly flaring drying chambena tube having substantially parallel walls disposed in a substantially upright position and opening into the flared chamber, means for feedinggnaterial'to be dried into the tube, means for passing a current of drying gas upwardly through the tube and'the chamber with suificient force 'to buoy up at least some of rthe material to'be dried, means for preventing turbulentflow of the drying gas in the tube, means for preventing turbulent flow of the drying gas in the lower portion of the flared chamber, and a baflie comprising radial plates disposed on a slant from the horizontal for abruptly imparting a swirling motion to the gas and the material buoyed up by it, said baffle being disposed in the path of the gas and transverse thereto at a level near the top of the flared chamber.

5. Apparatus according to claim 4 provided with means for adjusting the slant of the radial plates.

6. In a drier, the combination which comprises an upwardly flaring drying chamber, a tube having substantially parallel walls disposed in a substantially upright position and opening into the bottom of the flared chamber, means for feeding material to be dried into the tube, means for passing a current of drying gas upwardly through the tube and the chamber with suflicient force to I buoy up at least some of the material to bedried,

a level near the top of the flared chamber above the upright plates.

7. In a drier, the combination which comprises an upwardly flaring drying chamber, a tube having substantially parallel walls disposed in a substantially upright position and opening into the bottom of the flared chamber, the horizontal cross section of the tube being substantially the same as the horizontal cross section of the flared chamber at the level at which the tube opens into it, means for feeding material to be dried into the tube, means for passing a current of drying gas upwardly through the tube and the chamber with sufficient force to buoy up at least some of the material to be dried, means for preventing turbulent flow of the drying gas in the tube and the lower portion of the flared chamber, a first bafiie for abruptly imparting a swirling motion to the gas and, the material buoyed up by it disposed at a level near the top of the flared chamber'and transverse to the direction of gas passage, and asecond baflie to impart swirling disposedin the drier a; ove the first and transverse to'the'direction-of'gas passage. v

8. In a drier,*the combination 'which'comprises anjupwardly flaring drying chamber, a tube having substantially parallel walls disposed in a substantially upright'pos'it'ion and opening into the flared chamber, means for feeding'material to be dried into-the tube, meansfor passing a current of1drying gas upwardly through the tube and the chamber with sufficient .forceto buoy up at" least some of the1inaterial totbe dried, means for preventing turbulent flow of the drying gas'in' the .tube' and the lower portion of the flared chamber, and two superposed transverse baffles for abruptly imparting aswirling. motion to the gas'and the material buoyed up by it at a level near lthe'top of' the flared'tchamber, the lower of thetwoxbaffiesibeingnear'the top of the flared chamber and having radialjplates rotatable to a slant with the horizontal, andrmeans for adj-ustingrthe'slant of the plates.- 9. In a-drier, thecombination whichcomprises an upwardlyrfla'ring drying chamber, a tube hav ing substantially parallel walls disposed in a sub stantiallyzuprightposition and opening into the bottom of the flared chamber, means for feeding material to be dried into the tube, means for sucking a current of drying gas upwardly through the tube and the chamber with sufficient force to buoy up at least some of the material to be dried, means for preventing turbulent flow of the drying gas in the tube and the lower portion of the flared chamber, and a baffle for abruptly imparting a swirling motion to the gas and the material buoyed up by it disposed in the drier at a level near the top of the flared chamber and transverse to the direction of gas passage, a hopper below the tube and communicating therewith,

a pipe opening into the hopper, and means for applying a higher degree of suction to the pipe than to the tube and flared chamber.

10. Apparatus according to claim 9 in which the pipe is disposed upright and passes through the tube and the drying chamber.

11. In a drier, the combination which comprises an upwardly flaring drying chamber, a tube having substantially parallel walls disposed in a substantially upright position and opening into the bottom of the flared chamber, means for feeding material to be dried into the tube, means for passing a current of drying gas upwardly through the tube and the chamber with suflicient' force to buoy up at least some of the material to be dried, means for preventing turbulent flow of the drying gas in the tube and the lower portion of the flared chamber, a bafiie for abruptly imparting a swirling motion to the gas and the material buoyed up by it disposed in the drier at a level near the top of the flared chamber and transverse to the direction of gas passage, a hopper below the tube and communicating therewith, a flue passing upward and opening into the top of the hopper, means for introducing hot gas into the side of the flue remote from the hopper, and means for introducing cooler gas into the flue below the point at which the hot gas is introduced.

12. In a drier, the combination which comprises an upwardly flaring drying chamber, a tube having substantially parallel walls disposed in a substantially upright position and opening into the bottom of. the. flared chamber, means ;-for feeding? material to: be dried-together'withwarm gaseinto the tube, means i011 passing. a ;current of ;drying: gas .upwardlythrough the-tube zandethe chamber with 'suflicient force to rbuoy :up at.-1ea st some of the material tQ'bQtdIid, means'fonpreventi-ngturbulentflowof the dryinggas. in the tube and the lower-portion of the flared-chamber, axbaffie for abruptly imparting 'a swirling;:motion to" the; gas anq the; material buoyed. up by, it' dis poseclinthe i clrier at a level near'the" top of; the fiarecl chamber ancttransvers'e-to the direction of gaspassage; a'fiisintegratoriforthen'iaterial tbibe dried.connectedftortlieifeeltmeansiarrd'a conduit for: passing'zwarms gas into a he :disintegrator: from theztube 7' a 1' .'1.3.=;In=: a dryer. the" combination: which com; prises atube havingnsubstantially parallel walls disposed'iinc a; substantially upright position; an upwardly flaring'gdrying :chamberdisposed above theetube with itsbottomin rcommunicationzthere withgsmeans forfeeding material to'be dri'ediinto the-tube; vmeans for" passing a .current of; drying gasupwardly through the? tube and the chamber with sufiicient force" to: *buoy up a' large partiof the; materialto bezdried; means for preventing turbulentrfiowof'the drying: gasi-in' the-tube :and the'lower portion oflthe flared-chamber, atransverse' bafile for" abruptly impartinga swirling s am-s37 12 motion .toqthe. gas-and the material buoyedl up by ittdis'posed' at alevel near. the top of the-flared chamber, avchamherrcdisposed. above the flared chamber, and anroutlet conduit. tangential, to said,,upper,chamber'.

- PAUL A. SHAW.

v f REFERENCESCITED. The -following references are of: record: in [the filee-ofzthis-ipatent: i W "UNITED STATESPA I'ENTS iDateQ Shaw July. 4;"1950

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