US1874388A - Process and apparatus for manufacturing soap - Google Patents

Description

Aug. 30, 1932; p ws 1,874,388

PROCESS AND APPARATUS FOR MANUFACTURING SOAP Filed Sept. 20. 1928 INVENTOR Pl CE M. TRA VI 43 ER 5 ATTORNEYfi Patented Aug. 30, 1932! r "rear orrics PIECE III. TRAVIS, OF RIDGEWOOD, NEW JERSEY, ASSIGNOR TO TRAVIS PRQCESS COB- PORATXON, L? JERSEY CITY, NEW JERSEY, A CORPORATION OF DELAWARE P306338 AND APPARATUS 1 9?.- .HANUFAGTUB-EG SOAP Application filed September 20, 1928. Serial No. 307,321.

This invention relates to the manufacture of soap, and more particularly to a process and apparatus for continuously producing a marketable solid soap product directly from its raw materials relatively instantaneously as compared with the present commercial practice. K

The usual soap-making operation is generally recognized as an unduly protracted and involved procedure, and while constant efforts have been made to overcome these ob jectionable factors, no satisfactorily efi'ective and commercially practical solution has been found heretofore- The boiling or settled soap process by which soap is generally manufactured in present day practice, is a long drawn out and comparatively costly operation involving the use of cumbersome equi ment and an inordinate amount of space. I of fats by this process, a plurality of prolonged stages is required, including a sub stantial primary saponification, followed by salting out, washing, strengthening, fitting and settling. Thereafter, in the production of the vast majority of soaps, fillers and the like are incorporated in the hot settled soap, and the mass is run into large frames to cool. As generally conducted, a period varying from four days to a week or thereabouts consumed in carrying out the boiling and associated stages properly, and from three to six days in the usual frame cooling.

Formerly the so-called cold process was more widely used for soap manufacture'but that process has been more or less generally applanted by the more effective boiling process. According to the original cold process, suitable quantities of strong caustic and certain fats are agitated in a crutcher for a short time, and when proper mixture has been secured and saponification has progrossed to a suitable degree, the usual fillers,

' coloring material and the like are incorporated, and the reacting batch is run into frames and allowed to stand for several days to complete the saponification and then to cool, the heat used in the operation being mainly that developed by th action. The time element involved does ot dilier substantially from n the saponification' that of the objectionaiily protracted boiling process, for from six to ten days is ordinarily reguired for completion of the cold process.-

le from a manufacturing standpoint the process presents a less involved and more eth'cient type of operation than does the boiling process, certain technical deficiencies practically prohibit its use in place thereof and have causcd'its general abandonment in 'favor of the latter process. Its major disadvantage lies in the almost invariably incomplete saponification obtained as compared with the boiling process, for even with the exercise of all due care, it cannot be depended upon to produce soap of suitable and uniform quality. Soap made by the ordinary cold process is almost always characterized by -the presence of excessive amounts of free alkali and/or unsaponified fat, and by its tendency to discolor and rancidify in a relatively short time.

It is the object of my invention to provide a process and apparatus by which a marketable solid soap of uniform and high quality, may be continuously produced directly from its raw materials relatively instantaneously as compared with these recognized processes, and in a manner which is simple, practical and thoroughly effective.

According to my invention, a mixture of syrup consistency, containing the common soaporming fats, oils or fatty acids, either individually or blended in suitable proportion, and the alkali, in which mixture is ordlnarily incorporated the customary fillers such as sodium silicate, carbonate and the like, is subjected to an intense disrupting and dis persing action which increases the interfacial area and intimac of contact to such an extent that saponi 'cation is completed practically instantaneously, with the accompanying production of an extremeglhcmogeneous and fine mixture of the soap, ers and other materials used, and the resulting mass is then converted preferably substantially immedi' ately, into very small units, in which very accessible form it may be quickly dried and/or cooled and/or otherwise treated to yield a solid soap product.

' The preferred manner m which my inve tion is carried out is described in the following specification taken in conjunction with the accompanying drawing, in which,

Fig. 1 is a diagrammatic view of an illustrative combination of apparatus for carry in out my invention;

ig. 2 is a fragmentary cross-section on an enlarged scale of the cocnerating working surfaces of the SEPL tification-completing ap- 30 paratus used therein, for applying an intense disrupting and dispersing action.

Referring to the drawing, and in particular to Fig. 1, reference numerals 5 and 6 designate jacketed crutchers or agitators of an suitable and well known type, in which t 1e raw materials for the soap are pro-mixed and treated prior to their subjection to the intense disrupting and dispersing action, which is applied through the medium of mill 7.

.20 These crutchers are provided in appropriate number and are alternately charged and discharged so as to assure a continuous supply of properly pro-treated material to the mill. If desired a single continuous agitator into 2 which proportionate quantities of the raw materials are simultaneously and continuously metered may be used in place of the alternating crutchers. A common conduit 8 connects the crutchers directly with the mill 7 although indirect feed through an interposed butler or feed control tank may be used if desired.

In their passage through the mill 7 the properly mixed and pre-treated materials are 5 sub ected to an intense disrupting and dispersing action which increases the interfacial area and intimac of contact to such an extent that saponi cation proceeds to completion practically instantaneously.

An extremely intense disruption and dis-.

persion which very efi'ectively brings about such a result is that which is obtained for example, when a mixture of syrupy consistency containing the constituent materials of the soap, attenuated to accessible thin film form, is subjected practically simultaneously to a substantial high speed film shearing, a high speed film beating, and a violent agitation or eddying to relatively continually ex- 60 pose new surfaces of the film for shearing and beating.

A slmple mechanical means of applying such an action is provided by relatively moving cooperating working surfaces conngured for example, as shown in Fig. 2. In that construction, a rotor and a. stator member, designated 9 and 11 res ectively, provide the relatively moving mem ers, the coo crating surfaces of which are both formed wlth alternating, continuous longitudinal ridges or ribs 12 and channels 13. The ridges 12 terminute in substantially flat shearing faces 14 which form sharp edges 15 with the sides or heater faces 16 of the ridges. The channels 13 are preferably of smoothly curved crosssection to promote churning or eddying of the film being treated, for the purpose of continually exposing new surfaces thereof to the shearing and beating actions of the faces 14 and 16 respectively. A smooth curvature of the channels need not be rigidly adhered to however, although such conformation best promotes eddyiug. The sides 16 may for example form obtuse angles with the bottom of the channel, or be otherwise contoured to provide the desired result. 1

The rotor and stator surfaces are spaced with a very slight intervening clearance, to provide a narrow working gap 17 in which the materials are treated in.. thin film form. A clearance ranging between .002 and .010 inches 5: generally efi'ective for thorough saponification, although at particularly high rotor speeds this upper limit maybe somewhat exceeded.

The peripheral speed at which the rotor member is operated ordinarily, ranges from 3000 ft. to 5000 ft/ min. and sometimes higher, depending upon the width of the working gap 17, the nature of the materials being treated, and the intensity of effect desired.

A practical embodiment of the cooperating working surfaces of Fig. 2 in a highly efficientform is illustrated by the mill 7 of Fig. 1. This mill comprises a jacketed stator member 11 which defines an elongated chamber 18 of frusto-conical form, communicating at its smaller end with a feed chamber 19 and inlet 21, and at its larger end with a discharge chamber 22 and outlet 23. A rotor member 9 of a frusto-conical form similar to that of the chamber 18 is mounted for rotation therein in closely adjacent, non-contacting co-axial varied as desired by suitable longitudinal adjustment of the rotor. Furthermore, mate rials fed at the smaller end of the conical construction will be rapidy drawn towards the larger or discharge on by the accelerating action of the increasing centrifugal force, the degree of acceleration depending upon the slope, and the speed of the rotor. This rapid passage finds valuable application in large scale operation and provides adequate compcnsation in capacity for the treatment of the materials in film form rather than as a lar e mass.

n the event the passage of the material through the working gap 17 is too rapid for thorough subjection to the action therein, suitable retardation may be provided whereby the time or length of passage is appropriatcly est-ended. By roviding a longer gap' for example, and/or by decreasing the slope of the same, suitably prolonged subjection of thematerials to the action in the gap may be obtained.

A positively acting means by which retardation of discharge may also be secured, without too greatly diminishing the power advantages resulting from the inherent centrifugal acceleration, is provided, for example, by centrifugal impeller rooves 24, or by projecting fins if desired, disposed on a detachable or integral conical projection at the lar e end of the rotor 9. These grooves extend su stantially radially of the projection in equi-distant relation, and terminate in the channels 13 on the surface of the rotor proper. By suitably increasing or decreasing the number of these grooves the retardation may be intensified or diminished as desired. Variation of the number of operating grooves or fins may be accomplished for example, by using detachable groove fillers or detachable fins. Similar grooves 26 or other impeller faces may be provided on a similar projection 27 at the smaller end of the rotor,

- to aid the introduction of materials into the working gap. I

Rotation of the rotor and its accompanying projections is accomplished through the medium of a drivin shaft 28, which may he directly ccmiecte with a suitable motor, 30 through the medium of a flexible coupling which will permit longitudinal adjustment of the rotor, or which may be indirectly driven by beltv connection or the like.

The outlet 23 of the mill, which may be located at the top, bottom or intermediate points in the discharge chamber 22, is connected by means of a conduit 29 with an apparatus for convertin or breaking up the mass of material from t e mill into very small units in which form the soap is subjected to further treatment.

An exemplary and particularly effective operation of such a nature,comprises converting the mass of material into a fine spray and treating it in that form. As an illustration thereof I have shown in the drawing the ap plication of a spray drying apparatus of suitable and well known type.

For certain applications, the mill 7 is preferably connected with this apparatus through the intermediary of a control tank 31, provided with an external jacket 32 and an internal coil 33, for the circulation of a temperature regulating medium, and accommodating an auxiliary mixer or agitator 34. In this tank the temperature may be regulated as desired, additional materials incorporated in the soap which are not adapted for incorporation during the saponification operation, and other conditions controlled asdictated by the requirements of the subsequent operation. If desired, alternating control tanks may be used in the manner of the preliminary crutchers 5 and 6.

In other applications the mill may be connected directly with the spraying nozzles.

From tank 3]. the soap mass is delivered to spray nozzles 35- in a dryin tower 36 either under pressure provided by a pump 37, or by gravity feed supplemented by atomizing gas pressure at the nozzles, depending upon the particular application involved. Hot air or other dryin gas is introduced at the top of the tower tirough inlet pipe 38, and cooling air at the bottom of the tower through pipe 39. A discharge pipe ll leads from the bottom of the tower to a suitable cyclone collector 42, in which the solid soap particles are separated from the eiiluent gases and are discharged at outlet 43 indirectly marketable form.

.Specific spray drying apparatus of satisfactory application in the relation herein described, are those disclosed in U. S. patent types of soap stock, permits predetermined control of the glycerine content of the soap over a range which meets all ordinary demands. A small amount of glycerine is fre quently desired in soap because of its emol lient and lather strengthening properties, and by using suitable proportions of fatty acids with the fats or oils when necessary, the de'siied content of glycerine may be readily provided.

Mixtures of fats and/or oils with free fatty acid are not adapted for treatment by the ordinary cold process because of the tendency of the free fatty acid to prematurely combine with the alkali. This results in the condition called launching which is characterized by the mechanical enclosure of portions of unsaponified fat and/or oil, and al- -ka li by the rapidly formed soap. These lumps are very dillicult' to disintegrate by c'rutching and their presence in the finished soap results in poor-texture, rancidification and other undesirable features.

This bunching factor may be disregarded in the present operation, for any lumps which may form are readily disintegrated and completely reacted by the intense disrupting and dispersing action embodied in vided by the soap which is quickly formed by the free fatty acid.

Various exemplary soap stocks illustrating the wide range of mixtures which are worked yery satisfactorily by my process are as folows p 5 Because of the very-pronounced reaction- Palm kernel oil accelerating eiiect oi the intense disrupting stantially the theoretical quantity required and dispersing action comprised in my 'the ingredients, temperature regulation etc.,

process, the caustic soda and/or potash or other alkali need only be supplied in sub for the saponification of the soap stock, as indicated for example by the saponification value of the stock or by test runs. Where material amounts of commercial silicate filler are used however, as is usually the case in the production of laundry soaps, soap powders, bead soap, and the like, which com prise the largest proportion of soap manufactured, it is advisable to use caustic in excess of the theoretical to compensate for that taken up by the silicate. Most commercial silicate is unsaturated in this respect, the commonly used N brand silicate, for example, and it exhibits a tendency to absorb caustic. The approximate" composition of the so-calledfN brand silicate is as follows: Na20-8.9%; silica29.0%; water6'2%.

The excess caustic required under such circumstances however, is rather slight when the operation is properly conducted, for the caustic appears to react selectively with the soap stock and the silicate does not absorb 1t to capacity. This matter of caustic absorption by the silicate however, is of more advantage than disadvantage, for when material amounts of silicate are used,the inadvertent provision of alkali in moderate excess will not work commensurate injury in the final product because of the corrective action of the silicate. By the use of the less common and more expensive brands of silicate which contain their maximum amounts of caustic, this absorption phase can of course be readily eliminated, although such a procedure is unnecessary practically.

The mixed material to be introduced into the mill must be of suitable liquid consistency when supplied thereto if proper treatment is newness to be secured. The mechanical saponification -acceierating action in the working gap 17 is most effective, and of most eilicient application from a power consumption standpoint, when the material being treated is not the order of commercial U. S. P. glycerine;

The general range of suitable consistencies for the mixed mass is best designated as syrupy. The thickest workable consistency in this range, is determined by its amenability to eilcctive treatment and handling by the mechanical action involved in the particular op eration. The thinnest consistency utilizable ;is limited only by possible retarding effect upon saponification e. g. in the reduction of 7 the consistency by the use of water in amounts which cause undue dilution of the caustic.

Proper consistency, as well as mixture of action in the mill. In addition to aliordingcontrol of the factors noted, this preliminary crutchmg treatment serves other aluable purposes. The initial phases of saponification usually proceed quite readily because of the chemical afiinity of the soap-formin ma-- terials, and it is mainly with the final phases and the substantial completion of the saponification that the greatest diilicult is encountered. For this reason it is desirable and economically expedient to cause the reaction to proceed to a suitable extent without applying any considerable amount of external energy, and then to utilize the intense accelerating action in the mill for the completion of the remaining stages. In accordance with this economically and technically advantageous procedure, saponification is preferably carried to a satisfactory degree, depending upon the speed of reaction of the materials used, in

the preliminary crutching operation, with the advantages attendant thereupon of low power consumption, utilization of the heat of reaction to elevate the batch temperature, pro-regulation of consistency, etc.

The extent and manner of bringing about saponification in the crutching operation, will masses u foaming and securing proper consistency in the final clutched mass. With materials which react less readily or relatively slowly, the preliminary crutching should be used principally to bring about saponification to such extent as is practicahin which operation the incidental mixing will necessarily be very thorough, and in such cases the most advantageous temperatures are generally above those ordinarily dictated by the limitations of the original cold process. The possibility of bunching in the crutcher at high temperatures because of too ra id reaction, with resulting mechanical enc osure of unreacted materialbythe rapidly formed soap, presents no particular diliiculty in the present operation, for as noted hereinbefore in relation to the use of free fatty acid-fat mixtures, it is easily remedied by the subsequent intense disrupting and dispersing action in the mill.

The variations in temperatures, liquid content, period of crutching and similar operating conditions which are necessary to bring '(lifi'crcnt soap stocks and compositions to a "proper state of consistency, reaction and the like, or suitable and most economical treatment the mill, are not great and can be readily recognized or determined by one skilled in the art. In the matter of consistency for example, the visual observation 01' the. mass in the crutcher usually affords a fair criterion after slight experience with the operation of the particular mill. I

Satisfactory intitial temperatures for the melted soap stock range in most intances between 120 and 180 F., and for the caustic,

. between room temperature and 200 F., al-

the same.

though these limitations may be exceeded as the-circumstances may dictate and as will be apparent to one skilled in the art. The temperatures of the silicate, soda ash and similar solutions are likewise pre-regulated as determined by the particular operating conditions and the ultimate batch temperature desired. These solutions serve very effectively as temperature controlling media, to correct excessiveor deficient temperatures in the soap stock-caustic mixture. Their most general use in this respect is in the reduction of the excessive temperatures which frequently result from rapid reaction of the soap stock and caustic, often accompanied by excessive swelling and foaming, and in such application,-the silicate and soda-ash solutions generally can be used at substantially room temperature of a few degrees above or below By their addition at such temperatutes, the temperature of the batch can be reduced economically to a proper point for subjection to the saponification-acelerating action in the mill.

The caustic solution used should be fairly The addition of the soap stock is accom-' panied by rapid crutching, and the resulting mass is thoroughly and continuously crutched for several minutes to provide a reasonably homogeneous mixture of the consistency of thick syrup, and to accomplish a suitable saponification prior to introduction of the other materials. The fillers, such as sodium silicate and carbonate, trisodium phosphate, clay etc., are then mixed into the batch before it has thickened to a degree which would in terfere with crutching and subsequent intro duction into the mill. Upon the addition of sodium silicate, the use of which is generally desirable, the mixture becomes smoother and of thinner consistency.

After a suitable period of rapid and thorough crutching to intimatel and homogeneously incorporate the silicate, soda-ash, and/ or other fillers in the batch, the hot syrupy mass is then discharged into the conduit 8 and thence into the mill 7, through inlet 21. It is desirable that these feed lines should be kept well filled throughout the operation inorder to exclude air.

The temperature of the mass at-the mill in let should be preferably below the normal boiling point of water, e. g. 140-200 F., in

order that large amounts of steam will not be formed in the mill as a result of the heat developed therein, although the formation of,

some steam is frequently advantageous in promoting saponification and dispersion. This temperature can be readily obtained by properconduct of the crutching operation,

and if not, suitable correction can be secured by the use of a jacketed feed control tank as ictional resistance to syrupy mass will be rapidly drawn into the;

narrow conical working gap, and in accessible thinfilm form will be there subjected to a violent disrupting and dispersing action. As may-best be understood by an inspection of Fig. 2, the shearing faces 14 of opposite hydraulic shearing action upon ie film of liquid material therebctween, -etting up powerful disrupting and dispersing forces in the film; the sides 16 and the sharp edges 15 of the ridges will provide practically simultaneously with the hydraulic shearing, a beating action of pronounced disruptive and dispersive intensity; and the channels 13 will serve to promote the violent agitation or eddying in the liquid iilm for the relatively continual exposure of new surfaces thereof to the accompanying actions.

As a result of the action so constituted, and such other forces as may be inherent therein in addition to those noted, the particles of material in the working gap will be practically instantaneously disrupted to a quasicollodial size and thoroughly and uniformly dispersed in such form, with a resultant enormous increase in the inter-facial area and intimacy of contact of the soap stock, caustic, and other materials. With such reaction accelerating conditions prevailing, the unreacted soap stock will completely react with the caustic, and in some instances with some of the carbonate also, practically instantaneously. The resulting mass, will, moreover, contain the soap, silicate and carbonate and /or other materials in a. state of extremely fine and homogeneous mixture unattainable by any mixing action heretofore used.

The particularly effective nature of such intense disruption and dispersion of the materials is clearly demonstrated when it is considcred, that while completion of the final stages of saponification is ordinarily very difiicult to accomplish except by prolonged treatment, the acceleration of the reaction obtained as noted, is so marked, that saponification is carried to completion within the few seconds time which is required for passage through the working gap.

This specific manner of obtaining the saponification is the subject of my co-pending application Serial No. 307,322.

The hot mass discharged from the mill is then passed through pipe 29 either directly to the spray nozzles, or into the jacketed control tank 31, depending upon the requirements of the subsequent operation. In the tank 31 the temperature maybe elevated or decreased, additional ingredients admixed, and other conditions regulated as is desired or necessary, with the temperature, consistency, liquid content, and other conditions of the mass regulated as the nature of the subsequent operation dictates, it is then delivered under suitable pressure by the pump 37, for example, to the spray nozzles 35 in the drying tower 36, where it is dispersed into a 'fine spray which passes downwardly through the tower in contact with the hot drying gas introduced through pipe 38. In its passage through the tower the sprayed material is dried thoroughly, or to the extent desired, and after the temperature of the suspension has been suitably lowered by contact with the cooling gas introduced at the bottom of the tower through pipe 39, the suspended solid particles are carried through discharge pipe 41 into the cyclone collector l2, in which they are separated from the efiiuent gases and are discharged through outlet 43.

Where a thoroughly dried product is desired, the temperature of the gaseous sus- I pension should be maintained above the dewpoint until the moisture-laden gas has been separated in the collector. After separation,

further cooling of the solid particles may then be accomplished if desired, by the use of a second stream of cooling gas in conjunction with a second cyclone collector or in any other suitable manner.

The following exemplary operation for preparing directly a marketable finely divided soap from a specific soap stock will illustrate one application of the general meth- 0d of procedure described hereinbefore.

A strong caustic solution is prepared by dissolving 12 lbs. of caustic soda (98% pure sodium hydrate) in 35 lbs. of water at room temperature, whereupon a rise in temperature to approximately 190 F. occurs due to the heat evolved on solution. This hot solution is introduced into one of the crutchers 5, 6 and into it is poured, with continual crutching, a soap stock blend consisting of 63.75 lbs. palm kernel oil and 2 lbs. cocoanut oil fatty acid, at a temperature of F A rapid reaction takes place in the mixture with the evolution of an. appreciable amount of heat, and after three or four minutes crutching a batch of thick syrupy consistency is obtained with a temperature z-ctween 16G- 175 F. At this point 60 lbs. ofN brand sodium silicate at a temperature of 82 F. is crutchcd into the batch, and directly thereafter 17' lbs. of sodium carbonate solution (23% soda-ash) at a temperature of 88 F.

Upon the addition of the silicate the batch becomes smoother and of thinner consistency, and after a few minutes thorough crutching to secure intimate incorporation of the silicate and soda-ash, with a resulting temperature e. g. of F., the hot syrupy mass is passed through conduit 8 into the mill 7, which has been suitably preheated by circulating steam through the stator jackets. In its rapid passage through the mill the mass is subjected to the intense saponificationcompleting reaction described hereinbeforc, and its temperature is elevated in passage to F.

In the production, for example, of the product described in the Lamont patent hereinbeforg referred to, this hot mass from the mill is then passed through the control tank 31, and its temperature is quickly raised to 220 F. in passage. From the tank 31, the heated mass is delivered by the pump 37 to the spray nozzles 35 at a high pressure, and is sprayed into strongly preheated drying gas (500 F.) and otherwise treated in accordance with the teachings of the patent noted to obtain the desired product.

The particular saponification steps and ap paratus described hereinbefore, are peculiarly. and very advantageously adapted for use in conjunction with the spray processing disclosed in the Lamont patent. The conditions of consistency and moisture content.

(usually in the neighborhood of 40% and ranging between 30% and 15%) which generally prevail in the saponification phase are such, that the resulting filled soap mass is obtained in such suitable condition for the preparation of the Lamont product that no further adjustment of these conditions is necessary. The temperature at which the filled soap mass is best adapted for the spray processing (of the order of 220 F.), may be closely approximated in the mass discharged from the mill, so that any temperature-regulation required thereafter would he inconsiderable. The saponification operation may be carried out very effectively at temperatures just slightly below the boiling point of water, and with the pressure in the mill but slightly above atmospheric, the boiling point can easily be elevated to 220 F. or above. Under such conditions the control tank 31 may be dispensed with. i

Moreover, the finely divided product obtained by the specific combination in my basic process of the Lamont spray drying process, exhibits markedly improved qualities, over that obtained by like spray drying of a similarly constituted material containing soap prepared by the boiling process, and over finely divided soap products prepared by other known methods. A finely divided, spray dried soap product made by such specific combination, as described hereinbefore, is for example, almost instantaneously soluble with no sedimentation of silicate or other materials, it rapidly yields a closely knit and firm lather, contains practically no free al-- kali or unsaponified soap-forming stock, is of uniform and attractive appearance, and possesses very rapid and effective detergent properties. The folubility, sedimentation and saponification characteristics of a typical product for example, were as follows:

Five grams of the soap dissolved completely in 100 cc. of water at 50 C. in slightly less than 30 seconds, with no stirringor agitation.

Alkali determinations showed a content of .02% free alkali (NaOH).

N0 unsaponified soap-forming stock was present.

While I have noted the eminent applicability of in basic process in specific combinati on with the spray processing of the Lamont patent, for the production of a hollow particle of the structure described in that patent, it is likewise applicable with markedly improved results in the production of granular. shredded, powdered and other types of finely divided soaps wherein sprayin exuding, or other means of converting t .e soap mass into very small units for treatment may be used.

In additionto the pronounced reduction in operating time, the marked improvement in the product, and other novel features which result from this combination, of an intense disrupting and dispersin action for complating sauonificatien, with .a sub:equent conversion of the resulting saponified mass into the accessible form of very small units for rapiddrying and/or cooling or other treatment, this combination of steps in my process, with the conversion to small units in substantially immediate sequence to the intense disrupting and dispersing action, is of practically essential importance for the invariable production of improved filled soaps.

In the production of filled soaps, which usually contain sodium silicate and carbonate, intimate incorporation of the filler in the soap is essential, for with poor incorporation the soap will eliloresce and soda-crack on aging. The ordinary crutching operation which is used for this purpose, is at best not articularly effective, and thorough and uni .orm distribution of the filler throughout the soap is not obtainable without inordinately prolonging crutching, if then.

Moreover, even after apparently satisfactory incorporation, separation of the filler frequently occurs, with resulting detriment to the marketable quality and appearance of the soap. This separation usually takes place after the filled soap mass has been run into the frames. although it not infrequently occurs in the operations prior to framing, and the resulting solid soap cannot be economical- 1y 0: practically treated to correct the dithculty. The causes of such separation are rather obscure, and it has been variously ascribed to poor incorporation of the filler, crutching too hot or too cold, delayed framing, and other factors. The exact reason for the separation however, is usually difiicult of explanation, for evenwith extremely carein! repetition of a successful set of conditions, separation will frequently occur for no apparent reason at all. Inasmuch as filled soaps constitute the major proportion of presentday soap production, these ditliculties are of considerable importance.

In my process however, the intense dis-, rupting and dispersing action incorporates the filler in the soap in a state of extremely fine division and uniform distribution impossible of attainment by any degree of ordinary crutching, with the incidental combination in a single step of the separate saponifying and filling steps required in the boiled soap process, and the carrying over of such an enhanced degree of incorporation to the finished product is invariably assured by the conjoint use of the substantially immediately subsequent step of my process. By substantially immediately converting the homogeneous mass into very small units and rapidly drying it for example, while in such form',the detrimental filler separation characteristic of prior methods of production, is effectively eliminated and the extremely fine and thorough dispersion of my prior ste which provides a remarkably homogeneous and improved product, is obtained in every instance.

Furthermore, .the advantages of improved and uniform quality with extremely fine and homogeneous distribution of fillers and the like, obtainable by my process, are not confined to the production of soap in the form of small units, but may likewise be extended to the production of high grade cake soap if desired. By suitable treatment of the small units into which the saponified mass in my process is promptly converted, e. g. by suitable regulation of the temperature and volume of the drying gas in the spray drying operation to retain a suitable amount of moisture in the sprayedparticles, the units may readily be pressed together to form cakes. For this purpose use can be made, for example, of any of the well known squeezing or plodding machines, wherein soap chips are squeezed together and issue in the form of a bar which is subsequently cut into cakes for stamping and wrapping.

By the process and apparatus herein described, a practical manufacturing operation is provided which eliminates the objectionally protracter, involved and comparatively expensive phases of the usual soap making practice, adequate correction c: which has long been sought.

Of major importance is the great reduction in operating time accomplished thereby. In this novel opera tion the time consumed in the manufacture of the product in directly marketable form from its raw materials is but a matter of minutes as compared with the many days required in present soap practice.

Further supplementing its elimination of the inordinate time consumption required in the recognized boiling and cold processes, as well as its avoidance of their involved aspects, this novel operation supplies various other deficiencies of those processes, some of which have been noted hereinbefore, while providing added advantages.

The operation is simple in nature, involves but slight running expense. and provides a practically 100% yield. It can be carried on desired, its very effective treatment of pure' fatty acids, adapts it for use conjointly with the Twitchell or a similar process for obtaining free fatty acid and glycerine from the fats or oils.

In addition to this high degree of manufactnring efiiciency which the operation presents the soap obtained thereby is of uniform an greatly improved quality as compared with that obtained by prior methods. Unsaponi fied soap stock and/or free alkali are absent therein, and the soap exhibits markedly enhanced solubility, detergent properties and other desirable characteristics.

While I have described hereinan illustrative manner of carrying out my invention and certain applications thereof, my invention is not imited thereto or otherwise than as defined in the following claim.

I claim i The process of manufacturing filled cake soap which comprises subjecting a mass of syrupy consistency containing the soap stock, saponifying alkali and filler to an intense disrupting and dispersing action whereby a completely saponified mass containin the materials in a fine state of division an uniform dispersion is obtained, then spraying said mass while the materials are substan- 0 par tiallyrin said state, drying to a suitable de- CERIIFICATE or coamzcnou.

Patent No. 1,874,388.

I romeo M. TRAVIS.

It is hereby certified that error appears in the tirinted specification of the above numbered patent requiring correction as follows: Page 8, line 43, for ."protracter" read orotracted; same osge, lities 08 to 110, the claim, strike out the words "to a suitable degree, and then eompactingthe droplets eonsti-' toting the spray" and insert instead the droplets ceestituting the spray to a suitable egree and then compacting said units; and mar the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of November, A. I). 1932.

V J. Moore, (Sea!) Acting Commissioner of Patents.

Augtist 30, 1932.

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