US2152788A - Soap product and the manufacture thereof - Google Patents

Description

pr1T4, 939. ,w. H. BURKHART ET Al. 2,152,788

SOAP PRODUCT AND THE MANUFACT'UBB THEREOF original Filed May 24, 1953 l 2 sheets-sheet 1 erle fla/veau ATTORNEY I l l,

April 4, 1939. w. H. BURKHART Er AL 22152788 SOAP PRODUCT AND THE MANUFACTURE THEREOF Original Filed May 24, 1935 2 Sheets-Sheet 2 Patented Apr.` 4,.. 1939 PATENT -OFFICE SOAP PRODUCT AND *ma MANUFACTUB 'rnmuaor` William H. Burknart, Baltimore, Ma., and

Eugene. T. Marceau, Maplewood, N. J., assignors to Hecker Products Corporation, a corporation of New Jersey Application May 24, 1933, Serial No. 672,724 Renewed September 23, 1938 15 claims.

not soluble with sulicient rapidity and completeness, as of undesirable bulking weight, or as containing excessive proportions of dust. Attempts to overcome these objectionshave resulted in the production of particles of roiu'idedl or generally globular character and containing definite inthem, excessively high temperatures (in they terior voids surrounded by Walls or shells of solidied soap material.

currents which are at such high temperatures adjacent Ithe spray nozzles as to generate steam within the particles with consequent pronounced' inflation thereof. l The resultant rounded voidcontaining shell-like jparticles, while possessing the advantage of low bulking' weight, involve certain disadvantages. For example, they exhibit surfaces of vitried character which impede their solubility. Also, 4due to the necessity of expanding such -particles to obtain low bulking yweight by means of generating steam-internally within neighborhood of 400 F. or higher) are employed, but -only a small amount of the available heatis usefully absorbed in the process and the major part is wasted. i Again, the processes commonly employed for Athe production of the rounded shell-like steamexpanded particles of the prior art involve the inJection of the soap paste into the stream ofv heated air or gas atits hottest point in the spray tower, whereupon the moisture in the injected particles is -vaporized with resultant violent ination of the particle and escape of almost all of its moisture. 'Ihe bead-like pulled particles resulting -are undesirably low in moisture content. Such processes, moreover, as a result fof their employment of heated air b oth'as a drying medium and as a means for puiling the particles by lsteam generation, do not lend themselves readily to .variations in the rate o! production and at the same time to control of' the bulking weightk and moisture content of thev product.

The presentinyention follows'from our discovery that particles of rounded or globular voidcontaining formation are not necessary to the at- 0 tainment of a satisfactory andeicient soap product overcoming the.deflciencies of previous soap compositions. This invention provides a productl comprising agglomerations of particles aggregated together to form networks of sponge or coral-like .character in marked contrast to In the preparation of such products soap compositions are sprayed into air the hollow bead or shell-like soap products with4 interior voids which have heretofore been deemed essential for a satisfactory aked or powder-like soap material. In the novel product forming the subject ofthis invention, desirable low bulking weight is obtained without the generation oi? steam within the particles. Due to its agglomerated sponge or coral-like character, it presents a markedly extended surface area per unit of weight rendering it rapidly soluble in water oi' comfortable washing temperature. It further avoids a vitried particle surface and contains no material of 'any appreciable quantity which is not immediately soluble in water under ordinary conditions. It also avoids the dustiness that in prior products proved annoying to users and is of advantageous moisture content. This product,v referred to in the claims as a soap product, is

furthermore predominantly a soap in contradistinction to washing powders or soap powders wherein the major portion of the solid ingredients is soda ash. Our product aforesaid contains principally soap with no more than a small portion. of soda ash, in no case over 25%, and is producedby drying by evaporation and not by crystallization of sodium carbonate by cooling, as is the casewith soap powders. The production of this product, moreover, obviatesthe necessity of high temperatures such asabove referred to, and ena'bles the attainment of far greater eiliciency in the utilization of available heat with consequent small heat wastage.

'I'he process for the production of vthe aggregated-particle coral-like soap powder of our invention comprises the spraying of a soap-paste into a current ofa gaseous drying medium, such 'as air, which, while eiectively and expeditiously drying the composition to the desired extent, does not involve a steam-generating' inilating` action. The comparatively low temperatures employed contribute to ease of "control 'of the process, materially reducey fire hazards, and enable substantial economy in cost of apparatus and drying to be attained.- In addition,lthese temperatures substantially avoid dehydration of the silicate in the soap composition tothe point where such silicate becomes insoluble. They, moreover, permit theA use of..steam economically. for' heating the drying air, avoiding the use of combustion gases, or of oil fired heaters from which combustion gases may leak into the air, which gases, due to their carbon dioxide'content, 'are likely to convert the sodium silicate in the product into insoluble silica.

Other features and advantages of our invention will be hereinafter described and claimed.

In the accompanying drawings:

Fig. l is a diagrammatic view illustrative of apparatus which may be employed for carrying out the process of the invention.

IFig. 2 is a longitudinal sectional view showing a form of spray nozzle which may be employed.

Figs. 3 and 4 are photo-microscopic views of the product.

Fig. 5 is a view showing a modied form of ap. paratus which may be employed in carrying out the process.

In carrying out the invention a soap paste is prepared and passed through spray nozzles at the topof a drying tower. 'I'he paste may be formed from pure kettle soap or from such soap mixed with other ingredients in a mixer I of conventional typ Mixtures varying in content from 100% pure commercial kettle soap to a content of 60% pure commercial kettle soap and 40% other ingredients have been successfully handled. The mixture may be diluted with water to any desired consistency. It may be conveyed from the mixer I by a pump 2 to a reservoir tank 3, from which it is transmitted by a pump 4 through steam heaters 5 to the atomizing nozzles B in the top portion of the tower 1. Usually the paste as sprayed contains from 40% to 50%v water and is heated to approximately 200 F., although these figures may be varied.

The amount of soap mixture pumped to thenozzles may be conveniently regulated by operation of valve I controlling by-pass 9, whereby part of the material may be returned to the tank 3V depending upon the position of said valve.

In the nozzles the paste is subjected not only to the pressure of the pump 4, but also to the pressure of atomizing compressed air supplied to the nozzles from any suitable source. Pump pressures of from 60 to 75 lbs. per square inch and compressed air pressures of from 90 to 125 lbs. per square inch have been found satisfactory. 'I'he pressure of the compressed air supplied to the nozzles may be readily controlled by manipulation of a valve 6" in the compressed air line i. A suitable type of nozzle which may be employed is shown in Fig. 2, said nozzle comprising an opening I0 for the admission of the atomizing air, and

an opening II for receiving the soap paste. The air passes through the interior of a hollow tubular member I 2 containing a stationary helical element I3, while the soap paste, after entering a chamber Il, passes between stationary helical blades I5. The air and soap mixture thoroughly lntermingle in the space I6 and leave the nozzle through restricted opening I1. Due to the action of the air the soap paste or mixture is atomid in very small particles. These particles impinge upon each other upon leaving the nozzle; said particles being sulciently plastic to cohete and form agglomerates of highly irregular shape. 'I'hese agglomerations, as will later'b noted more particularly, consist of minute individual particles aggregated together with interstices therebetween and resembling coral in formation.

As the particles emerge from the nonies-they meet an ascending column of warm drying air supplied to the bottom portion of the tower l by a blower fan Il through steam heaters I l. The rising column of air slows the 'speed of fall of the particles and maintains them in air suspension for an appreciable period. Through the steam coils I! the temperature of the air, and hence its drying capacity, may be increased to auch point &

as will enable drying to be carried out at the desired rate; the temperature to which the air is heated depending upon how much material it is desired to dry for any given volume of airand how much moisture it is desired to remove. The temperature of the air can be readily regulated to the desired point by controlling the amount of steam passing through the heaters I9 by any suitable valve, as will be apparent.

It will thus be noted that the amount of moisture dried from the material, or, conversely, the amount of moisture left in it, can be regulated at will without any change in the characteristic form of the product. A too high moisture content in the dried material leaves a product of a sticky plastic nature, of no practical value commercially; while the material tends to become friable in character and prone to break down into dust when the moisture content is too low. A moisture content between 15% and 25% by weight is desirable, the most preferable being around 18% to 22%, and this is readily obtainable. Through variation, individually or collectively, of the amount of drying air supplied per unit time, the temperature of the air, and the quantity of soap paste supplied to the spray nozzles per unit time, the moisture content of the product may be brought to any desired value.

As the air passes upwardly through the tower in a direction opposite to that of the falling soap particles, it is of course dropping in temperature due to its absorption of moisture from the soap particles and is becoming more saturated with moisture throughout its upward course. However, as its temperature drops and its moisture content increases it is continually contacting with soap particles of higher moisture content so that its heat and drying capacity can be used to a maximum degree. The air exhausted from the equipment frequently has a relative humidity as high as' 75% which indicates the degree of eiliciency in the use of heat and drying capacity of the air, and thus the efilcient operation of the process from the standpoint of heat expenditure.

It will further be observed that the rate of production may be expeditiously controlled by simply varying the amount of paste pumped through the spray nozzles per unit time and correspondingly regulating the drying capacity of the air, as by appropriately changing its temperature. With air supplied at the rate of 20,000 cubic feet per minute and a iinal moisture content in the product of 18% to 20%, an air temperature of 160 F.

in front of the heaters I9 has been found suitable for a production rate of 1800 pounds per hour l(referring particularly to a product having the composition hereinafter specified by way of example), while an increase of said air temperature to about 200 F. enables the rate of production of said product to be approximately doubled. The production rates obtained with these temperatures will, of course, vary with the moisture content of the atmospheric air.

Figures 3 and 4 illustrate microscopically the physical structure of the product, these views showing typical agglomerate particles made up of smaller particles aggregated together with in` terstices therebetween. The sponge or coral like character' of the agglomerates is clearly apparent aisance 3 I' erate particles are irregular with resultant spaces between the, agglomerates in the'package. One advantageous soap product. of a composition later `to be discussed more speciiically and produced in accordance with this invention has been found to have an apparent specific gravity oi' between about .30 and .35 as packaged. In other words its bulking weight is between approximately 18% and 21% pounds per cubic foot.

The size Aofthe agglomerates is illustrated by the following representative mesh analysis (made with standard screens): p

Percent Through 10 mesh screen 100.00 'I'hrough 20 mesh screen 85.00 Through 40 mesh screen 53.00 Through 60 mesh screen.- 33.00 Through 80 mesh screen 10.00

The above. percentages are by weight.

The drying air leaves the tower 4at the top through a. duct 22, thence passing through a dust collector 23 containing screens 2F of canvas or other suitable material for removing any fine particles that may have been carried along with the air. The latter is discharged to. the atmosphere by exhauster fan 25. 'I'he particles removed from the air by the screens 24 are collectedin hoppers 26 from which they may be removed when desired- In this connection the screens aforesaid may be tapped or shaken'automaticallyat regular intervals by any suitable andl well-known apparatus. The particles removed from the hoppers 26 may be incorporated with the soap'and other ingredients supplied to the mixer I and returned therewith through the spraynozzles 6. The particles which descend through the drying air i'n the tower 1 are received upon conveyor belts 21, 28, whence they are passed through a 'chute 29 onto a conveyor belt 30. While on' the latter saidparticles may be passed through a cooling chamber 30' wherein theyA are subjected to a current 4oi.' air of suitable cooling temperature' supplied by a fan or other source, for rev ducing their temperature to any desired extent.' From conveyor 30 the particles are-passed through' a sifter Il of appropriate mesh, for removing any oversized agglomerates, and are thence carried by conveyor 32 to'conventional packaging machines.

The drying rate may be substantially expe-- dited, and accurate control facilitated, byo pro-- viding within the tower 'lian inner wall 33, having its intermediate section `co'nstricted, as shown, with respect to its end portions 34, y35. A passa`ge of'Venturi character is thus provided with consequent increase in velocity o1' the air.through the major portion of its travel through th'e tower.

vIf desired', the space 36 between the inner and outer walls of the tower may be supplied with warm air fromfan I1 and heaters 38, as indicated, to prevent loss of heat by radiation from the air within the inner wall Il vor to further` s the mesh analysis hereinbefore given..

increase the drying capacity of said air by radiating heat thereinto through said inner wall. The outer wall [may be of suitable heat insulating construction.

By way of a specific example of the ycarrying out of the invention there may be mixed together in'themixer i ingredients in substantially the following proportions:

Pounds Kettle soap; 720 Sodium silicate y 144 Sal lsoda 117 Scrap (which may be taken from hoppers 25 or from the material-rejected by sifter Il, or both) 100 To the above, water an amount up to ap-i proximately 175 pounds is added to facilitate mixing. These materials'are introduced into the crutcher or mixer l at -a temperature such that the temperature of the resultant paste -is about 170-175 F.v As has been noted, the paste isV pumped into reservoir I; from which it is conveyed by pump 4 through heaters 5 into thespray nozzles. I. While the temperature of the paste is raised to about 200 F. in the heaters 5, it

may be pointed out that the heaters, though conv venient, are noty essential, and that paste at a temperature of 170 to 175 F. can be sprayed satisfactorily.

'I'he paste prepared from the ingredients in the the following formula:

After being sprayed and passed through-the sifter 3l (the screen of which is of preferably 10 mesh, i. e., 10 openings per lineal inch, or 100 openings per square inch), the product is passed on to `the packaging machines. The composition of the finished product prepared from the ingredients in the proportions above specied by way of example, is approximately as follows:

Per cent Water Dry soap y 08 Dry silicate 1.5v 'Dry sodaash y 4.5

The above percentages, as are all other percentages herein given, are by weight. j

. When the said product is\taken from the cooling belt it is generally at a temperature of about aoa5 F. scia product has a. bulking weight of between approximately 18:*/4l and 21% 4 pounds per cubic foot, or an 'apparent specific gravity, Ywhen packaged, between about .30 and .35. The size of its agglomerates is illustrated by proportions above speciied has approximately Per cent Water 46 vDry soap 46 Dry silicate l v 5 lDry soda ash E 3 'I'he rapidity andcompleteness of solution of the aforesaid product is evidenced by the following test: 4 grams of said product ,was placed in 250 cubi centimeters of. distilled water at a temperature of F. and agitated for two minutes with an yagitator operating at 200 revolutions per minute (the particular .agitator employed being known as the Cenco universal friction drive motor stirrer manufactured by Central Scientific Company, Chicago, Ill., and shown in their Bulletin No. 85, September, 1924). At the end of two minutes a portion of the solution was filtered through a cotton plug to remove undissolved soap particles,

`and 25 cubic centimeters pipetted from the illi tered solution. The 25 cubic centimeters of filtrate were evaporated to dryness at 110 C. and the total soap therein determined. The weight of the portion remaining was then converted to percent dissolved product on the basis of the original sample, making proper adjustment for the original moisture content of the sample. From this test it was established" that 9,8% of the product was dissolved in said two minute period. The aforesaid product (i. e., as withdrawn from the tower) is found toV contain less than 0.10% matter insoluble in distilled water at 200 F., the average water insoluble matter amounting to only 0.04% or 0.05%

It will, of course, be understood that the foregoing specific ingredients and proportions thereof are set forth only by way of example, and as hereinbefore indicated, the proportions may be widely varied, mixtures ranging from a content of 100% kettle soap to 60% kettle soap and 40% alkaline salts and other ingredients having been successfully spray dried in accordance with this invention and producing agglomerate particles having the characteristics above specifically discussed.

The bulking weight of the product will vary with the composition of the soap paste employed. For example, the bulking weight of the agglomerate particles produced by spraying a composition consisting of 100% pure kettle soap in accordance. with the above described process, maybe as low as 10 lbs-12 lbs. per cubic foot. On the other hand, a decrease in the percentage of kettle soap and a corresponding increase of alkaline salts -as compared with the example hereinbefore specifically given, will result in increase of bulking weight ofthe agglomerate particles. All specific gravities and bulking weights herein mentioned refer to the product as packaged.

at this stage occurs at a moderate speed, leaving the particles of such plasticity that the particles will adhere upon impingement, but they are not sufficiently fluid to lose their identityl throughcoalescence into a. larger solid particle. T'his is in marked contrast to prior methods wherein the particles are sprayed into a. zone of dry air Kof kmaximum temperature with consequent extremely rapid drying and immediate loss of plasticity preventing agglomeration. In addition,- it is to be observed that due to the upward now, in the present process, of the air against the downwardly moving particles, agglomeration is further facilitated since the downward progress of the finer particles is substantially impeded or prevented, affording increased opportunity for contact between these and other particles. In short, by delaying the passage of particles 'through the tower, the up materially ag lomeration between the various Vfull cross-section of the tower.

rdly moving air current expedites particles. Also, in the present process the soap is atomized from the nozzles in. the form of a fine mist, with the result that the agglomerates vformed are of the mesh sizes above indicated in .connection with the finished product, while still containing a very large number of individual parlticles as sprayed; as distinguished from prior processes wherein the particles as sprayed are in the form of drops of substantial size and unagglomerated in the finished product.

`As shown in Figure 5, the inner or Venturishaped wall 3l may be omitted and the drying air caused to travel upwardly throughout the The outer wall 1 is of suitable heat insulating construction.

'I'he terms and expressions which we have ernployed are used as terms of description and not of limitation, and we have no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but recognize that various modifications are possible within the scope of the invention claimed.

We claim:

1. A spray dried soap product comprising aggregates consisting of minute sprayed particles cohering togetherwith interstices therebetween and without external void-defining shells, said l impingement while in 'suspension in a gaseous' medium, said aggregates being subsequently dried while in suspension in a gaseous medium to reduce the plasticity thereof and prevent the adhesion of said aggregates to each other upon emergence from said medium, certain of said aggregates being of such size as to pass through a mesh sieve and others comprising accretions of particles sufficient in quantity to prevent passage through a 60 mesh sieve but capable of passing through a sieve of 40 mesh.

i 2. A spray dried soap product comprising aggregates-consisting of minute sprayed particles cohering together with interstices therebetween and without external void-defining shells, said aggregates being formed by the accretion of said minute particles and the cohesion thereof upon impingement While in suspension in a gaseousA medium, said aggregates being subsequently dried while in suspension in a gaseous medium to reduce the plasticity thereof and prevent the adhesion of said aggregates to each other upon emergence from said medium, over 25% by weight of said aggregates in samples/of a. regular commercial run passing through a sieve of 40 mesh and over 25% by weight of said aggregates being too large to pass through said 40 mesh sieve.

3. A spray dried soap product comprising aggregates consisting of minute sprayed particles cohering together with interstices therebetween and without external void-defining shells, said aggregates being formed by the accretion of said minute particles and the cohesion thereof upon impingement while in suspension in a gaseous medium, said aggregates being subsequently dried while in suspension in a gaseous medium to reduce the plasticity thereof and prevent the adhesion oi' said aggregates to each other upon emergence from said medium, said product containing, by weight, over 15%' water, and over 45% dry soap- 4. A spray dried soap product comprising aggregates consisting of minute sprayed particles cohering together with interstices therebetween and without' external void-defining shells, said soda ash.

emergence from said medium, said product con-I taining', by weight, over 15% water and over 65% dry soap,approximately 7% dry silicate, andJa'pproximately 4% dry soda 5.- A spray dried soap product comprising aggregates consisting of minute sprayed particles cohering together with interstices therebetween and without external void-deilnlng shells, said aggregates being formed by the accretion of said minute particles and the cohesion thereofupon impingement while in suspension in a gaseous medium, said aggregates being subsequently dried while in suspension in a gaseous medium to reduce the'plasticity thereof and prevent the-adhesion of said ,aggregates to each other upon emergence from said medium, said product containing, by weight, over 15% |fwater, over 45% dry soap, over 7% dry silicate and over 4% dry 6. A spray driedsoap product comprising aggregates consisting of minute sprayed particles cohering together with interstices therebetween and without external void-defining shells, said aggregates being formed by the accretion of said minute particles and the cohesion thereof upon impingement while.y in suspension in a gaseous medium, said aggregates being subsequently dried while in suspensionin a gaseous mediumto reduce the plasticity thereof and prevent the adhesion'of said aggregates toeach other upon vemergence from said medium, over 25% by weight of said aggregates in samples oi a regular cornmercial run passing through a sieve of 40 mesh and over 25% by weight of. said aggregates being too large to pass through said 40 mesh sieve, said aggregates being formed by the accretion of said product containing, by Weight, over 15% of water and over 45% of dry soap.

7. A spray dried soap product comprising aggregates consisting of minute sprayed particles cohering together with interstices therebetween and without external void-defining shells, said minute particles and the cohesion thereof upon impingement While in suspension in a. gaseous vmedium, said .aggregates being subsequently dried while in suspension in a gaseous-medium to reduce the plasticity thereof 4and prevent the adhesion of said aggregates to eachother upon emergence from said medium,`said product containing water, soap, and a silicate, and contain- `ing less'than 1% by weight of insoluble silicate.

8. A spray dried soap product comprising aggregates consisting of minute sprayed particles cohering together with interstices therebetween and without external void-,denning shells, said aggregates being formed by the accretion of said minute particles and the cohesion thereof` upon impingement while in suspension in a gaseous medium, said aggregatesbeing vsubsequently dried while in suspension in ya gaseous medium to reduce the plasticity thereof andprevent theadhesion of said aggregates toeach other upon A emergence from said medium, which -product when placed in water at 100?` F..lin the proportion of 4 grams of said product to 3/4 liter of water and agitated by a rotary stirring device at the e rate of 200 revolutions per minute for a. period of two minutes is approximately 98% dissolved while in suspensionl in a gaseous medium to revduce the plasticity thereof and prevent the adduce theplasticity thereof and prevent the adhesion of said aggregates to each other upon emergence from said medium, said product having a bulking weight greater than 10 pounds per cubic foot.

1 0. A spray dried soap product comprising aggregates consisting of minutesprayed particles cohering together with interstices therebetween and without external void-defining shells, said aggregates being formed by the accretion of ,said

p minute particles and the cohesion thereof upon impingement while in suspension in a gaseous medium, said aggregates being subsequently driedwhile in suspension in a gaseous medium to ref duce the plasticity thereof and prevent the adhesion of said aggregates to each other upon emergence 'from said medium, said product having a moisture content of between and 25% by weight and having a bulking than 10 pounds per cubic foot. Y

11. A spray dried soap product comprising aggregates consisting of minute sprayed particles cohering together with interstices therebetween and without external void-defining shells, said aggregates being formed by the accretion of said minute particles and the cohesion thereof upon weight greater impingement while in suspension in a gaseous medium, said aggregates being subsequently dried while in suspension in Aa gaseous medium -to re- -duce the plasticity thereofand prevent the ad- -hesion of said aggregates to each other upon` together with soap and\lsoday ash, the percentageA of soap exceeding that of the soda ash.

l2. A spray-dried soap product comprising aggregates consisting of minute sprayed particl cohering together with interstices therebetween and without external void-defining shells, said 4emergence from said medium, said product containing by weight, between 15% and 25% water.

aggregates being formed bythe accretion of said minute particles and the cohesion thereof upon impingement while in suspension in a gaseous medium, said aggregates being subsequently dried hesion of said aggregates to each other uponemergence from said medium.

A13. jA spray-dried soap product comprising aggregates consisting of minute sprayed particles cohering together with interstices therebetween and without external void-deilning shells, said aggregates being formed by the accretion of said minute particles while in suspension in a gaseous medium and while of sumcient plasticity to cohere upon impingement, said aggregates being subsequently dried by passage through said mediumvto reduce the plasticity thereof and prevent the adhesion of'said aggregates to each other upon emergencefrom'said medium."

14. A spray-dried soap product comprising aggregates consisting of minute sprayed particles cohering together with interstices therebetween and without external void-dening shells, said nuedium and while of sufficient plasticity to cosubsequently dried by evaporation during passage through said medium to reduce the plasticity thereof and prevent the adhesion of said aggregates to each other uponemergence from said medium.

p 15. A spray-dried soap product comprising aggregates consisting of minutesprayed particles cohering together with interstices therebetween and without external void-dening shells, said aggregates being formed by the accretion of said Ahere upon impingement, said aggregates being

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