Nov. 19, 1946. L. sENDER MANUFACTURE 0F SOAP Filed Nov. 25, 1943 . \ ÈQ .Q mmh@ „Èk QN \ . 2,41 68 | Patented Nov. 19, 1946 2,411,468 UNITED STATES PATENT OFFICE 2,411,468 MANUFACTURE 0F SOAP Leopold Sender, Baltimore, Md., assignor to The Sharples Corporation, Philadelphia, Pa., a cor poration of Delaware Application November 25, 1943, Serial No. 511,705 1 claim. (c1. 25o-4.18,) The present invention relates to the art of soap making, and was conceived as a method of mak 2 practice of the present invention, the fat and re agent are ñrst mixed during maintenance of a ing soap continuously with the aid of centrifugal separators. saponifying temperature to cause saponi?lcation, Processes for the manufacture of soap by pass Ul and the soap formed as a result of the reaction is grained. The resulting mixture is then subjected ing a saponifying reagent continuously into con~ to aging by maintenance of a period of relative iiuence with a source of fat, saponifying the fat quiescence or lesser degree of agitation, and the by passage of the mixture at saponifying tem mixture of grained soap and spent saponifying perature continuously through mixing apparatus, reagent is then subjected to a further period of and separating spent reagent from soap by cen agitation in order to provide sufficient dispersion trifugation are described and claimed in the pat of the soap in the aqueous phase to afford sub ents of Ashton T. Scott, 2,300,749 and 2,300,750, stantially uniform distribution of the Soap in that of November 3, 1942. The present invention is phase as the mixture is passed to the centrifugal primarily a development and improvement with separator for separation of the spent reagent respect to the procedure of these two patents. 15 from the grained soap. In the processes of the above-mentioned Scott The succession of steps of the invention as de patents, the fat is continuously saponiñed by scribed above, may be performed both in the ñrst treatment with a saponifying reagent such as lye, stage of soap making as described in connection the saponilication being accomplished by in tensely mixing the fat and lye while passing them 20 with the ñrst stages of the respective prior pat ents to Scott discussed above, and in any or all at a saponifying temperature through mixing of the series of subsequent saponifying stages of apparatus. The resulting soap-containing mass which each involves addition of saponifying re is maintained under intensive agitation until it agent, graining and separation as described in is passed into a centrifugal separator for remov the prior Scott patents. Each' stage in which a ing the spent aqueous reagent from the soap. saponifying reagent is added is thus referred to The soap is grained, and thus conditioned for re as a “saponifying stage” herein, eventhough the moval of the spent aqueous reagent, prior to cen addition of saponifying reagent in the last such trifugation, by the addition of a salt solution, or stage may be wholly or partly for the purposes of an excess of saponifying reagent which serves as a salting-out agent. In -the process of Patent 30 recovering glycerine and preparation for finish-J ing, and `no actual saponiñcation occurs in such 2,300,750 the salting-out operation is accom plished by addition of the salting-out agent be fore the start of the saponi?ication reaction. The present invention may include any or` all of the features of either of the prior patents to Scott discussed above. It includes steps of effect ing continuous saponiñcation by passage of the fat and saponifying reagent together through a stage. By the practice of the invention as discussed above, the following advantages are attained. The quiescent treatment or churning obtained in the aging step causes a change in the mixture which facilitates subsequent centrifugation.Y It has been found that, in cases in which saponiñed and grained mixtures presenting substantial dif ñculty of separation are obtained in the practice tion of a salting-out agent either simultaneously with the saponifying reagent or subsequently to 40 of the Scott patents, the practice of the interven ing aging step in accordance with the present addition thereof, and centrifugation of the mix invention assists in avoidance of these difficulties. ture of spent saponifying reagent and grained 'I‘he aging treatment also provides a longer soap resulting from the saponiñcation while the grained soap is in a condition of substantially 45 time of contact between the fat and lye, or the formed soap and lye, and this longer period of uniform dispersion in the spent saponifying reagent. contact with the saponifying reagent tends to destroy constituents of the mixture which would 'I‘he novel feature of the present invention con otherwise cause rancidity of the soap after the sists in the fact that the mixing step by which intimate contact of the saponifying reagent with 50 soap-making operation has been completed. In addition to the above advantages, the aging the fat is attained to cause the saponification treatment, by giving a longer time of contact of and to bring the soap formed by the saponifying the unsaponified fat with the lye, assists in deple reaction into a state of uniform dispersion is tion of the lye and attainment of a higher degree divided into two steps, and a step of aging is in of saponiñcation. terposed between these two mixing steps. In the 55 The detailed nature of the invention and its saponifying mixer, graining the mixture by addi 2,411,468 attendant advantages will be better understood by consideration of the following detailed de scription in the light of the attached flow sheet, in which the single figure illustrates a preferred embodiment of the invention. Referring to the flow sheet by reference char acters, fat from container lil is passed into con ?luence with saponifying reagent from container I I. This saponifying reagent may be an aqueous solution of lye and salt, designed to effect saponi ñcation of the fat and graining of the soap formed by the saponifying reaction, as described in Scott Patent 2,300,750. As illustrated in the 4 ly saponiíied mass containing the soap formed in the first stage is subjected to a second stage of saponiñcation in order to complete conversion -of the source of fat into soap. As in the prior Scott patents, this may be accomplished by in troduction of the saponifying reagent into the cover of centrifugal Ii. Thus, a solution of lye and brine, which may either be a fresh solution or a solution derived from' a subsequent stage of treatment, is introduced into the cover of centrifugal H by pump IB, and the resulting mix ture is passed thence by pump 2e to mixer ZI, through this mixer 2l to ager 22, and from ager 22` through mixer' 23 to centrifugal 24, these ele ments of the iiow sheet accomplishing the same functions as are performed by the pumps and elements I4, I5, I6 and I'l of the ñrst stage of flow sheet, the solution of lye and brine em ployed in the ñrst stage of saponification may be a solution derived in whole or in part from the step of separation of a subsequent stage; the process, as described'above. y i. e., the process may involve counter-,current The soap discharged from the second stage operation as described in the prior Scott patents. centrifugal 24 may be subjected to further treat The fat from container> Il] and saponifying re 20 ment, as described in the' two Scott patents re agent from container il may be pumped into ferred to above, andif such further treatment confluence with eachother' by'` pumps I2 and includes further steps of saponification, they will i3, which pump these' material-s to' and .through preferably include an aging step, as described the mixer' Ill in' the desired> ratio. The reaction above with respect to the first two stages of treat 25 mixture, or its constituents, isv (are) heated to ment. The performance of the step o'f aging has a temperature (e. gv., 200° F.) sufficiently high to a particular advantage in the' last stage of soap effect saponi?ication of most of the fat during making, since the maintenance of` the fully passage through the mixer iii. The mixture is saponiiiedl soap-containing mixture in contact maintained in a state of intensive agitation with an excess of the free alkali for' al substan during passage through'l the mixer' iii in order 30 tialpe'riodl of time? assists in avoiding rancidity, to insure rapid saponiiication of the fat.V When as discussed. above, and it is therefore desirable a graini-ng' agent suoliY as salt 'isi included with to provide an aging period after the fat has been ` the saponifying reagent-y the' soap i's lgrained fully saponi'fied. promptly upon formation thereof. It is possibile, The partly' spent aqueous solution discharged however, to introduce the saponiïfying reagent 35 from the centrifugal 24 may be passed by pump and graining agent separately, as described in 25A to' container' ifi for re-use in the first stage Scott Patent- 2,€§00,-749, and when operation of of the' process, in order to make the' process truly this type is» accomplished, the grain'ing agent is counter-current, as' described in the Scott patents preferably added before the' reaction mixture to above. ' leaves the mixer it, orat least before it enters 40 referredv Various modifications" in the' above-described the ager I5. procedure are available to the person skilled in 'The reaction mixture is passed continuously the art', and are' hence within the scope of the from mixer id through an aging tank i5. The invention. For' example, instead of including the mixer it is' preferably provided with agitating grainin‘g reagent' as a part Yof the saponifying blades to' insure violent agitation, but the- ager solution, this grain'ing" reagent may he'V added I5 need not be' provided with such elements. It subsequently to' the saporliifying» reagent, as de isi desire-bie' that the mixture be gently agitated scribed iii Scott Patent 2,300,749. Many other . during 'passage through the' ager i5,` but this pos'sib'ilities for'modiñc'atiorl falll within the scope result can be accomplished. either by the" natural of tine> invention,~ and' Ido not therefore, wish' to movement of the' mixture through th'a't tank, or be' limite'dl excep-tiby- the scope olf the following by provision of agitating blades which provide much: less violence: than that maintained in' the mixerV I4. - . , . As the? result of th‘e' aging step performed dur' claim. ' ’ " In the manufacture of soap, the' process com prising continuously converting fat into soap by in'g' passage of the mixture through the ager »f mixing'said fat vigorously with ai sa'ponifyin'g~ re the material flowing from that mixer will agent' at a' saponifyin'g temperature during pas ordinarily be l’e'ss' nearly uniform in composition sage' through a mixing Zone‘,graining. the soap than that flowing into containerï i5 fron'iï mixer resulting from .said mixing' step', thereafter pass M; In order' to insure eiîi'cien‘t centrifugation of ing.' the resulting mixture of grainedvsoap and this material, - iït» is- desirable aqueous phase' through an aging zone in: which to» a higher degree of agitation that main th'eï mixture is' churn’e'd by agitation 'of a' degîrl'ee tained in container le, atleast for a b‘rie'ff period less than. that maintained in the' preceding mix'. before centri-fugationi.4 This iis accomplished: by ing zone', passingv a'q'e'ous phase andv grained soap v passingl the 'material through a'. mixer I6 which from said'. aging zone into a secondi n'rrixingiv aon'e provides the desired degree' of agitation and' ef' in which they are agitatedV more vigor‘fousl'yî> than fects uniform`~l dispersion of the soap’in‘ th'e' aque in the aging Zone until substantially uniform ousl phase before the` materiali enter-‘si the'.` cen dispersion of. the soapri's obtained, and' fina'ily trifugal'. " f passing the mixture resulting from agitation in From mixer'Y I6, the' mixture of> spent' reagent saidi last-mentionedY mixing ZoneA to a centrifugal 70 and graine'dl soap'li'sì passed to’centriïfugal. l'! for separator and thereby separating th'eï grained separation of the spent reagent fromI the soap- as soap- from aqueous phase.> in the YtwoSco'tt pa'terlits> referred toi above'. AfterÍ discharge from centrifugal» Iî'l ,. th'eï large VLit'oroLD- senese'.