US2612266A - Cooling of sprayed products - Google Patents

Description

Sept. 30, 1952 I J. A. MONIQK v 2,612,266

cooLmc 0F sPRAYED PRODUCTS Filed Oct, 11, 1945 z Sl-IEETS -Sl-IEET 1 INVE OR.

v Ala/7n )4. M k

Sept. 30, 1952 Filed Oct. 11, 1945 'J. A. MONICK 2,612,266

000mm: OF SPRAYED PRODUCTS 2 SHEETS-SHEET 2 I c/o/m ,4. Manic/ Patented Sept. 30, 1952 COOLING OF SPRAYED PRODUCTS John Alexander Monick, New York, N. Y., assignor to Colgate-Palmolive-Peet Company, Jersey City, N. J., a corporation of Delaware Application ctobcr-11, 1945, Serial No. 621,715

This invention relates to the cooling of sprayed soap and like particles and is especially concerned with a process and apparatus for the cooling of solid particles which have been formed by spraying a liquid product into a gaseous heated medium, as for example soap particles made by the process known as the spray tower process. The term soap includes detergents and like solid substances used for cleaning.

According to presently used spray tower systems for making granulated, powdered and like particulate soap, liquid soapis introduced in the form of a spray and mingled together with blasts of hot air in a tower wherein droplets of liquid soap become individual solid particles and fall to the bottom of the tower in such form. In practice the entering liquid soap is about 240 F. while the heated air into which the liquid soap is sprayed is at about 460 R, these conditions prevailing at the top of the tower. At the bottom of the tower, the soap particles having been formed, the soap temperature is reduced to about 110 F. while the air temperature is only about 130 F.

Normally therefor soap particles at a temperature of about 110 F. are drawn outof the bottom of the. spray tower and introduced into a cyclone separator which separates these particles from the air, the air being exhausted and the particles being dumped onto a conveyor belt which in turn delivers the still warm particles to a cooling device. The usual cooling device comprises a rotating drum through which the soap particles flow longitudinally, and at the same time the particles are exposed to a counterflow of I cooling air through the drum. The interior of this cooling drum ordinarily contains spiral-baffle blades for assuring that the soap particles move continuously therealong duringrotation of the drum. i Thistyp'eof cooling device has caused considerable difficulty in the, past because the warm soap particles, still at a temperature of about 110 F.or slightly less, tendf'to cake behind the.

blades and build up a coating on the interior surface ofthe cooling drum.l.Accumulation of such soap particles eventually, increases the weight of the cooling drum", thereby requiring v more power to rotate itv or cutting down its speed and therefore its efficiency. In practice it has often been found necessary to shut down the entire tower and process for a period of about a one day every two weeks in order to manually loosenand remove the caked soap particles from the interior of the cooling drum This shut-down not only holds up production, but it requires the 2 Claims. (Cl. 209-139) labor of several men working for a full day to clean the drum which is of considerable size.

I have also found that the forced feed and tumbling about of the particles passing through the cooling drum results in crumbling and powdering of the particles, thereby producing fine dust which causes sneezing and like discomfort to the user of the product.

In solution of the above problem, I contemplate omission of the rotary cooling drum and substitution therefor of a mechanically stationary device which will reduce to a minimum physical handling of the soap particles during cooling and will adequately cool the soap particles to a temperature at, which they may be safely packaged without the danger of caking. I accomplish this cooling in the preferred embodiment of the invention by producing a special counterflow of air relative to a stream of the relatively hotsoap particles to be cooled, and I have found that in additionto providing very efficient cooling of the soap particlesthe operation removes small particles of a size which correspond to dust in the final product and which may cause sneezing to the user of the packaged soap.

Withthe above in mind, it is a major object of my invention to providev a novel stationary apparatus for cooling soap andlike particles with minimum mechanical handling.

.It is afurther object of the invention to provide a novel manner of passing air or some other gaseous substance in counterfiow relation to a stream of soap or like particles to be cooled whereby eflicient coolingisobtainedand whereby small dust particles which may cause sneezing of the eventual user of the packaged product are removed.

It is afurther object of, myinvention to provide a special cooling tower for cooling discrete warm soap particles which is of special shape for maintaining substantially constant air velocity therethrough counter-current to the stream of soap particles and ,wherein the velocity of the cooling air is maintained in excess of the terminal settling velocity of desired size of small dust particles which it is desired to remove from the product. I

.It is a further object of the invention to providea particulate soap cooling tower having novel arrangements for producing turbulence of air flow for efilciently reducing thetemperatureof the soap particlesto a level where the product maybe packaged without caking. I

A further object of the invention is to provide a novel tower arrangement for cooling soap particles with minimum mechanical handling and wherein soap dust particles smaller than a given size are removed from the product, in which perfume is sprayed into the product followingthe cooling and dedusting operation and just prior to packaging, whereby considerable saving in the amount of perfume used is efiected since the perfume is not volatilized as much by the cooler particles as it is in prior art arrangements wherein the perfume is usually incorporated into quite Warm soap particles prior to cooling.

It is a further object of the invention to provide a novel combined soap particle making and cooling tower therein the still warm soap particlesafter manufacture in an upper spray. tower section drop into a lower cooling tower section wherein they are subjectedgto the action .of turbulent cooling air before leaving the tower and before being packaged.

Further objects of the invention will presently appear as the description proceeds in connection with theappended claims and the annexed drawings wherein:

Figure 1 isa flow diagram of an apparatus and process for making, cooling and packaging soap particles according to a preferred embodiment of the invention;

Figure 2 is a section through the cooling tower on line 2-2 of Figure 1 illustrating the counterflow of air which produces the turbulence in the cooling operation; a a 1 Figure 3 illustrates diagrammatically a further embodiment of the invention using a cooling tower having an internal air supply arrangement diiferent from the cooling tower of- Figure -1; and

Figure 4- is a combined flow diagram and substantially diagrammatic view of a combined spray 1 tower and cooling tower according to a still 'further embodiment of the invention.

Referring now to Figure 1, the usual spray tower H- is provided at its topwith a hot air conduit l2- connectedto a suitable source of pressurized heated airand a liquid soap spray nozzle I3, by which charges of hot air and sprayed liquid soap are continuouslydischarged and intimately. mixed withinthe top of the tower.- The droplets ofJ-liquid-soap change to particulateform as. they fall from the topto the bottom of the tower. The spray tower may beofthe type-dis closed in Uhl Patent No. 1,782,054 to which reference-is made for. moreedetail. Since thisis a conventional spray. tower process for making soap particles, it is not. necessary to go intofurther detail;in. description of. the same except to; observe that by. reason of the turbulent flow -conditions existing within. the tower it is apparentthat frequent collision of soap particles with each other and the incomplete forming ofcertain particles .williresult in aproduct wherein many of the particles are of undesired small size; some even approachingthe verysmall sizewhich is-nowrecognized as the: dust: that causes sneezing tothe consumer whena-package is opened. The. formed soap particles I which are usuallyat atemperature of about 110 F. are collected} inthe conical shapedlower-end M of the spray tower II and withdrawn therefrom through the-conduit; l5 to be-dischargedinto the cycloneseparator lfiwhich separates the particulate prod= uctzfrom thehotair. The hot air is' discharged fromseparator. lfiithrough outlet conduit [1 and the. product soap particles aredischargedthrough conduit l8 into the-specialcooling tower lil of" the invention.

Qoolings.tower. l 9 '-maybe --regardedas essentially composed of three vertical sections, the lowest substantially frusto-conical downwardly converging section 2| wherein the side walls are disposed at an angle of between 30 to 45 to the vertical, a relatively short intermediat section 22 where the side walls are substantially vertical so that this portion of the tower is sub stantially cylindrical, and a longer-Z upper up wardly converging section 23 in the shape of a truncated cone wherein the side walls are disposed not more than about 20 to the vertical.

Adjacent section 22, the tower is surrounded by an annular manifold 24 providing a pressurized chamber which is connected by a conduit 25 to a source of air pressure such as a suitable blower fan (not shown). Manifold 24 is provided with internal apertures so that it serves as an annular nozzle for discharging air into the tower. An auxiliary air supply is provided substantially centrally of the tower and at about the level of housing 24 in a form of radially open nozzle 26 supplied by a conduit 2! connected to a suitable source of air pressure. As illustrated best in Figure 2, the air entering tower I9 from a plurality of apertures in manifold 24 is so directed by suitable bafile plates or blades 28 as to create a generally circumferentially traveling air current which is substantially concentric with section 22. Similarly, nozzle 26 is provided with circumferential outlets and suitable directional baiile plates or blades 29 whereby the escaping air therefrom travels in a substantially circumferen' tial swirling or spiral path which is counter current to the swirling motion of the air entering from manifold 24, so that within section-22 of tower 23 there is violent turbulence due t0 the interference of the two opposed swirling streams of air under pressure.

As illustrated in Figure 1, the upper end of tower I9 is connected by a conduit 3| to the suction end of a cyclone separator device 32 which separates air transversing conduit 31 from any small soap particles which have-beenpicked up thereby-and the separated small soap particles are delivered through a conduit 34 to a suitableremelt station (not shown) so that none of the product is wasted. The separated'air is' ex'-' hausted at 33. Due to the suction through con duit 31, the turbulent air stream within section 22 isdrawn upwardly through the falling stream of warm soap particles.

As further illustrated in' Figure 1, the cooled larger soap particles collect in the conical bot-y tom section 2| of the'cooling tower' l9 which they-may drop onto a' conveyor b'elt 35'or the like for removing-them to a rectlyon the packaging machine.

According to the invention, the drop-in tem perature of the air cooled soap particlesbyth time they arrive in lowest section2l ofcdoling tower l9-issuch that they'do not tend to cake oragglomerate. There is'a minimumldfhiii dling of the particulate soapprior'to packaging so that the tendency to formfurther fine 'p'a'i 'ticles'in the-product'is considerably'reducedfl The size'of cooling tower I9 is usuallyidet'erf mined by the degree cf'cooling necessary tore duce the soap particles todesiredtemperature. Forexample; it is usually desiredfto' redu' temperature -of the soappa'rticl'es'to at lea, F'.priorto packaging. Ifthesoap'p rticls enterthe cooling tower ata temperature of "1 1 0" and are --to be"dischargedftherefromi "1 or-less; it is'necessaryto consider the tem eraturei ofthe entering cooling air in" orderto estimate hopper 136' di' the amountofair required to efiect'the desiredheat transfer; --For a latitude the neign q hoo'd'of New York city, the surrounding 'ai-rfte'm'f per'atufe is' rar ely higher than*85 F. even in: summemso that Withdrawing cooling air directly from-the surrounding atmosphere into jconduits 25 and 21 of my-appara'tusi and considering the specific heat-' of air to be 0.237 B: t ugper'pound per degree Fahrenheit-,-"I-haveestimated the. would require a; circulation or about thir thousandg-three hundred" cubic feet cram erf minute: to: reduce the temperature or 'tne- -soap partimee from 110" F. E 90"- Fi-evenwh 'e outer ou'ts'i'de air te'mperaturewas 85 E ch1 in'g tower having a diameter of approximately ten feet would have to be about twenty five iee't in hei'ght to -be satisfactory under-suchconditioIlSl I-t is to" be understoodthat' ths' diliie'fi sions 'an'd "calculations are exeniplary only a" in -n'o way' -restrictive' of'the invention;-

I have found that-by utilizingthe' op swirling: air supply arrangement' 'illustrated'in Figu'rR 2 al'1d withtheup'p'er'ehdmfthe to er at reduced pressuredueto'it's connection th; V the suction end"0f separator 32", adequat alidem'cie'ribcoolin'g of the' ialling soap p readily; obtainable withir'rth'e' tower-yan'dthe coo i'ng toweris continuous in operation since it is" not subjected to such inherent l operaticnal de fect's as would 'require-it t'o 'be 'shu t down 'i meaning like the prior art-cooling' -drumsi Inf addition to--' adequately c'oo'li g"--the particles-any above described mannefiofpr'ea a; tiirbulent c'ounterfiow df "air throughfthedrop? ping soapparticles 'remov'es therefrom al- I particle'sj b'elo'wapredeter' ed parti'clesizefan N ther'eby removes from thef-pro duct those small ones or dust}-pa'rtieles-{which cause sneezing-slitheu'ser' ot-the final package?" It is" infconne c'tion or dust-fromthe-pro'duct-that the upper section 23 of the tower is advantageously shaped with a slight taper (up to about"'2 0), the purpose of this taper being'sto provide a gradually reducing cross section of the tower for producing a sli'ghtly F I ticles" of ver'yflight'weight'when iallowed to "drop freely through a-viscuous medium suchj asl"air' dof-n'ot gfall according to" the" ordinaryfla'w of grayityi; Some timeafter itstarts to fall; each light 'pa'rtic :le oi" appreciable surface area reaches a settling velocity *where 'thef I upwardly acting forcefof air'r'esistance to its fallis 'equal'v lto'the gravitational force, and "a "furth'e gain in 'speed' isjimpossible at this point; 1 The Jp'articlefis then said to'have' "attained terminal velocity.

In practicing the invention, I -calculate the velocity ,of the upward flow of air in tower 1 9, which is high enough to jus'texceed the terminal velocitfofthe small particles of dust which I wish to remove from the product. This terminal velocity of small particles of dust may be calculated mathematically approximately by any the various available theoretical equations or laws of streamlined motion. This terminal velocity may be approximately calculated for example by Stokes law for the speed ofa particle falling in a viscuous medium, as described in Meston Patent No. 2,091,514 to which 7 reference'is madef-for iurthr deta mfthematica calculat1 I h"know ledg of t e apniftixl matfl ebfp hjpar lei b bef th r w f' m thei a l e roril fot,al 5a1 lici i v terminal velocity may be calculatd' sufii'ciefit i p' e w hths n a1 i n: o th t although the nature oi the mfat'eri'ali an, ve w t p of i icnrrsn s ch m y mn oye ih wer mey'v gr h du l V lue ettlin gvelqcityso tn" v s o i Pacev t a r u" 'I fhavefoundthat .very sati for umhsmly' d c n a m mn awr a t s iefplpeit i fi n general 58 5913 1 ,unwa velocityji'sta equate 'iqreflicient particle ,cj 1i 11y size'dfltower' itis' hifg. much he dust part 'c1es. It' will b ap enterin' air and thef manner of or tingtur; bulenc n the" intermediate sec 1onof' the nii we 11m r Vibem 1 11 21 fli pre d w t he "s meann l j a n ac n sm l p rtur to" jozzlef38 bei' ig'fconnectefdto a suitable so a of; ornpress'ed" air or" ,tl ljlikQ xtepfi for: su Sti'tiitidli 0f IIOZ 'ZIBB for E218 2? thei cdb ngi tower of Figure} is exactly vthe V Figure 1, the" ar anges fit; or; A s

f l l imr m 'le are be n H Withirg;

Si'iiC th'' SO ap;pal'tic1 are nowrr o fgdlls and considerably, cooledfso: that there"; is no vaporization offthe'fpferf iune, this produces af saving Sin enuine. whieh is an" expensive in art eiln i leriei ifil ie dei 'ii QilfiQiIi 1111a efcombine W n a s ra i erleomrl prism up rcase? M h jel nsat' siloweri z e t d ab t-e n s th c0Q1 n 0W r-,-

soap particles. The warm soap particles at about 110 F. temperature collect in the lower generally conical portion of spray tower 4| and are funnelled into the top of cooling tower 19 so that the falling warm soap particles are immediately subjected to the swirling and countercurrent action of the up-flowing cooling and dedustin'g air stream from nozzles 24 and 26. In this manner the soap particles are cooled to at least about 90 F. for safe packaging, and' the heated air containing the smallparticles of dust removed from the product is exhausted through conduit 3| as in Figure 1. I V

In this embodiment of the invention I have therefore combined in a single installation the conventional type spray tower with the cooling tower'of my invention, thereby further elimi'. nating mechanical handling of the soap particles.

between the spray tower and the coolingto wer and reducing to a minimum mechanical handling of soap particles after they have been formed and prior to packaging, while at thesame time insuring that their temperature is 'sufiiciently low prior to packaging that there is no objection-' able lumping or agglommeration of-the particles in-the package. The conduit 3| as in Figure 1 is preferably connected to a waste bin wherein the'discarded' soap dust and particles are collected and remelted and used again for introduction through nozzle 46. Y- 1 l The invention may be embodied in other's'p'e'ci fic forms without departing from the spirit or essential characteristics thereof. embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. A cooling and classifying tower for treating hot, lightweight spray-dried particles which.

have been removed from a spray-drying tower while above a predetermined maximum packag-' ing-temperature comprising; means defining a vertically elongated chamber,- the interior of which presents an unobstructed cooling passage having an inner wall of substantially circular cross-section; means at the top of said chamber for introducing said particles in a stream of air into the upper end of said passage'atthe axis thereof; an air outlet at the top of said chamber surrounding and above thepoint of introduction of said particles; a first annular" air introduction nozzle around the periphery of said chamber adjacent the lower end thereof; baflle means in said nozzle for directing said air tangentially around said inner wall of the chamfber in one direction; a 'secondnozzle located at substantially the axis of said chamber "and in the same horizontal plane as said first nozzle for introducing cooling air at a controlled ve- The present troduction nozzles, the'wall of the compartment,

merging with the inner wall of the chamber terminating in a product outlet through which theremaining cool particles are removed for pec s na;

2. A process of gents after they leave a spray-drying tower at a temperature above a predetermined maximum packaging temperature which comprises, entraining said" particles in a fluid stream, introducing said stream carrying said particles vertically downwardly, into the central portion of the upper end of a vertically elongated cooling zone through which the particles may freely fall,

establishing two oppositely directed coplanar circular movements of cooling air substantially transverse to the path of the freely falling particles at a point below their introduction into said zone, causing said cooling .air to flow upwardly counter to the path of said particles through said cooling zone at a velocity exceeding the terminal settling velocity of certain of said particles, removing the cooling air with said certain of said particles entrained therein at a point above the point of introduction of the particles into the cooling zone, and collecting the-remainder of said particlesbelow the level of introduction of saidco'oling air. 7 1

V JOHN MONICK. 7

REFERENCES CITED The following references are of record in'the file of-this patent: v

UNITED STATES PATENTS Number Name Date 530,445 Newby Dec,4,- 1894 572,091 Marsden Nov. 24, 1896 880,242 Robinson et al -fFeb. 25,: 1908 1,080,066 Johnston Dec. 2, 1913 1,210,868 Steckle -Jali. 2, 1917 1,509,915 Stebbins Sept. 30, 1924 1,517,900 Gay Dec. 2, 1924 1,734,260 Lamont; Nov. 5,1929 1,769,721 Sturtevant July 1,1930 1,354,209 McLean A r.1'9,f1932 1,897,144 Prouty f Feb.14, 1933 2,001 ,184 cu y May 14, 1935 2,026,833 Holland-Letz Jan. 7, 1936 2,421,840 Lechthaler et a1. June 10, 1947 FOREIGN PATENTS Number 'Country 1 Date treating small lightweight hot spray-dried particles containing organic detera Great Britain Nov. 2, 1942

Claims (1)

1. COOLING AND CLASSIFYING TOWER FOR TREATING HOT, LIGHTWEIGHT SPRAY-DRIED PARTICLES WHICH HAVE BEEN REMOVED FROM A SPRAY-DRYING TOWER WHILE ABOVE A PREDETERMINED MAXIMUM PACKAGEING TEMPERATURE COMPRISING; MEANS DEFINING A VERTICALLY ELONGATED CHAMBER, THE INTERIOR OF WHICH PRESENTS AN UNOBSTRUCTED COOLING PASSAGE HAVING AN INNER WALL OF SUBSTANTIALLY CIRCULAR CROSS-SECTION; MEANS AT THE TOP OF SAID CHAMBER FOR INTRODUCING SAID PARTICLES IN A STREAM OF AIR INTO THE UPPER END OF SAID PASSAGE AT THE AXIS THEREOF; AN AIR OUTLET AT THE TOP OF SAID CHAMBER SURROUNDING AND ABOVE THE POINT OF INTRODUCTION OF SAID PARTICLES; A FIRSTS ANNULAR AIR INTRODUCTION NOZZLE AROUND THE PERIPHERY OF SAID CHAMBER ADJACENT THE LOWER END THEREOF BAFFLE MEANS IN SAID NOZZLE FOR DIRECTING SAID AIR TANGENTIALLY AROUND SAID INNER WALL OF THE CHAMBER IN ONE DIRECTION; A SECOND NOZZLE LOCATED AT SUBSTANTIALLY THE AXIS OF SAID CHAMBER AND IN THE SAME HORIZONTAL PLANE AS SAID FIRST NOZZLE FOR INTRODUCING COOLING AIR AT A CONTROLLED VELOCITY; A PLURALITY OF BAFFLES IN SAID SECOND NOZZLE FOR DIRECTING THE COOLING AIR IN THE OPPOSITE DIRECTION AROUND SAID CHAMBER; SUCTION MEANS CONNECTING WITH THE TOP OF THE CHAMBER FOR MAINTAINING A PRESSURE DIFFERENTIAL BETWEEN THE UPPER AND LOWER ENDS OF SAID CHAMBER WHEREBY THE AIR TRAVELS TURBULENTLY UPWARD AND OUT OF SAID OUTLET AT THE TOP OF SAID CHAMBER AT A VELOCITY SUFFICIENT TO ENTRAIN CERTAIN OF SAID PARTICLES, AND A COLLECTING COMPARTMENT HAVING A DOWNWARDLY COMVERGING WALL BELOW SAID AIR INTRODUCTION NOZZLES, THE WALL OF THE COMPARTMENT MERGING WITH THE INNER WALL OF THE CHAMBER TERMINATING IN A PRODUCT OUTLET THROUGH WHICH THE REMAINING COOL PARTICLES ARE REMOVED FOR PACKAGING.

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