US1912637A - Manufacture of soap - Google Patents

Description

June 6, 1933. w. A. HARPER .MANUFACTURE OF SOAP Filed Sept. 23. 1930 2 Sheets-Sheet l mvENToR BY jag/641 0 A ATTORNEY June 6, 1933. w. A. HARPER 1,912,637

MANUFACTURE OF S OAP Filed Sept. 23, 1930 2 Sheets-Sheet 2 Patented June 6, 1933 rarsirrr orries WALTE A. HARPER, or NEWARK, NEW JnnsRy MANUFACTURE OF SOAP Application filed September 23, 1930. Serial No. 483,832.

The present invention relates to a process and apparatus for the manufacture of soap, andhas to do particularly with a novel process and apparatus for converting the hot liquid or molten soap of ordinary commercial manufacture into solidified cakes or bars suitable for sale and use. The invention contemplates the process and apparatus and also the improved soap product produced by the 1 process. A

In present common commercial practice of manufacturing bar laundry soap, the hot liquid soap from the boiling or saponification pans is run into frames, either. with or with out incorporation of additional appropriate detergent agents or filling materials, and is then allowed to stand in the :frames until it has cooled andsolidified, The soap frames are ordinarily upright tanks or containers, open at the top, which holda very substantial' amount of soap, say from 500 to 1,500

pounds. Theframes are filled with hot liquid soap and are then allowed to stand at room temperature until the soap has solidified, the timerequired for solidificationbeing ordinarily three or four days to a week depending upon the temperature, weather conditions, and the like. The frames are provided withremovable sides so that after the soap has solidified the sides of the frame can be removed to thereby make the solidified block of soap available for handling,

The solidified block of soap from the frame is then slabbed and out into cakes or bars of the desired size; The top portion of the block of soap taken from the frame is sunken in, broken and irregular due to irregularities which were left on the top surface when the soap was poured into the frame and due particularly to shrinkage and settling of the soap during cooling. A considerable amount of the upper portion of the framed block of soap, say six to twelve inches, must be cut off and discarded as scrap. The sides of the frame usually bulge, and the framed block of soap must be squared up before slabbing and cutting, therebygiving rise to additional scrap. After the framed block of solidified soap has been trimmed and squared; it is out into slabs of thickness equal to one dimension of the desired soap cakes, and the slabs thus obtained aresubsequently further out to obtain cakes of the desired size. More scrap soap is derived from the waste edges in this operation and still morewaste soap is produced if the cakes are cut down into any shape other than rectangular. In ordinary commercial practice, from to 40% of the total amount of soap framed is scrap and must be reprocessed. Theoperation as a whole is cumbersome, requires much time,

.mold soap in individual molds which are then carried through a refrigerating medium to effect solidification of the soap. Most of these proposed ideas have not been successful'due to impracticability from an operating standpoint in commercial scale production, expensive and complicated apparatus, prohibitively large size of apparatus required for tonnage production, lack of dependability of the apparatus, excessive labor costs relative to the amount of product produced, inability of the apparatus to produce a proper quality of soap, and the like.

It is an object of the present invention to provide process and apparatus for manufacturing soap wherein the ordinary hot liquid soap of regular commercial manufacture,

either filled or unfilled, is converted into a thoroughly satisfactory bar soap of uniform high quality by an operation which is largely automatic and which iscompleted in a very short time at exceptionally low cost.

It is an obiect of the invention to provide apparatus for conducting the process which is compact, simple and reliable, which occupies a small floor space relative to the amount of product produced, which is readily adaptable to large tonnage production, which requires a very small amount of power for operating, and which is substantially entirely automatic so that but one operator is required for an extremely large soap production.

It is a further object to provide, in the regular commercial run, an improved bar soap product, substantially as described below.

It is a further object of the invention to provide a process which comprises certain steps, fully described below, which I have found to be essential or of particular advantage in the commercial manufacture of the soap. The successful operation and the practicability of the process in commercial production depends largely upon observance of these steps and upon the observance and control of certain process conditions, all of which I have practiced in actual operation and have described fully in the following specification.

The invention can probably best be described by first describing a form of apparatus in which the process can be successfully conducted. In the accompanying drawings, Figure 1 is a view, partly in plan and partly in horizontal section, showing an apparatus embodying the invention; Figure 2 is a vertical sectional view taken centrally of the apparatus of Figure 1 on the plane indicated by line 2-2; Figure 3 is substantially an end view of the apparatustaken on line 3-3 of Figure 2 and Figure 4 is an end view, somewhat diagrammatic and taken from the opposite end of the apparatus, further illustrating the operation.

According to the present process, the soap is molded in a plurality of relatively long tubes, the cross-section of which corresponds in size and shape to one crosssection of the desired soap cakes, whereby cakes of the desired size are formed by cutting the molded rod of soap into appropriate lengths. In the drawings, the soap molding tubes are indicated at 1. It is an object of the invention to provide for a large production capacity in a single machine which occupies a relatively small space. This is accomplished by mounting the soap molding tubes 1 in rotatable end plates 2 and 3 in circular rows extending around the end plates and in banks extending radially of the end plates, the apparatus here shown comprising five tubes in each bank and twenty-four banks of tubes spaced angularly about the end plates, as shown in the drawings, particularly Figure 3. This arrangement provides for an exceptionally large number of soap molding tubes arranged in closely adjacent relation so that the apparatus as a whole is particularly compact and yet is capable of containing and processing a large amount of soap. End plates 2 and 3, together with the respective banks of tubes 1 mounted therein. are rotatable as a unit about a horizontal axis. End plates 2 and 3 are keyed to the horizontal shaft 4, as shown, so that the shaft rotates with the end plates and the tubes. At one end of the apparatus, shaft 4 is mounted for rotation in a bearing 5 supported on a suitable pedestal or foundation 6; The other end of shaft 4 terminates in end plate 3, and end plate 3 is provided with a trunion portion 9 which fits over and rotates on a heavy stub shaft 10 which is supported by a pedestal or supporting member 11.

The power for rotating the soap molding tubes 1 is furnished by a motor 12 which, in the embodiment shown, drives shaft 4 through the medium of various speed reducing gearing and other driving connections,

which are shown in the drawings but need not be here described in detail. The banks of tubes 1 are rotated with an intermittent movement, which is effected as follows: A plate 40 carrying a cam 41 is interposed in the driving connections between the motor 12 and the rotatable tube banks. Plate 40 does not rotate, but is slidable lengthwise of its shaft. Cam 41 is engaged by follower 42, which rotates with the driving mechanisms, and follower 42 thus pushes plate 40 along its shaft against the action of spring 43, which thereby engages a clutch, indicated generally at 44, and thus establishes driving connection. Cam 41 maintains the driving connection for a time just suflicient to rotate the tube banks through one position. The apparatus here shown is so designed that each partial rotative movement of the tube banks carries the tubes through an angular distance corresponding to the distance between adjacent tube banks. As will later be described, the periods of rest between periods of movements are sufiicient to permit filling and discharging of the banks of tubes which have moved into position for these respective operations.

The hot liquid soap, which serves as a source of supply for the apparatus, is stored in a container 14 which may be a soap kettle, jacketed storage tank, crutcher, or the like. Soap is discharged from container 14, through an appropriate outlet pipe 15, into a stationary manifold 16 which comes into register with one of the tube banks at the position indicated at 17, as best shown in Figures 3 and 4. The soap entering manifold 16 is placed under pressure as, for instance, by introducing compressed air into tank 14, or by providing a pump which delivers the hot liquid soap to manifold 16 and maintains it under pressure, or by mounting tank 14 at sufficient height to give the desired pressure. When a bank of tubes comes into register with manifold 16, in the position indicated at 17 in Figures 3 and 4, hot liquid soap from the manifold simultaneously enters all of the tubes ofthe bank and flows along the length of the tubes until the tubes are completely filled. The fillingoperation takes place duringthetime when the tubes 1 arestationary. The driving apparatus then causes the tube banks to rotate intofthe next position, which brings the next succeeding bank of tubes into register with the filling manifold 16. A stationary end plate 18 and 2 of the drawings.

. 10 having a ground fit with tube plate 2 is provided adjacent the outer surface of tube plate 2 as shown. l/Vhen a bank of tubes is rotated out of filling position, the inlet ends of the tubes are immediately covered by plate 18 which thereby seals off the tubes, preventing admission of further soap to the tubes, preventing escape of soap from the tubes, and preventing ingress of air into the tubes.

lVithin each of the soap molding tubes 1 is a plunger 19, the cross-section of which corresponds in size and shape to the inside of the tube so that the plunger has a tight fit with the inside of the tube but is capable of moving back and forth alongthe length of the tube. hen a bank of tubes 1 comes into the filling position, the plungers 19 within therespective tubes of the bank are in position adjacent the inlet ends of the tubes, this being accomplished by the regular routine of automatic operation described below. As the hot liquid soap from manifold 16 is admitted into the tub-es 1 during the filling operation, the pressure ofthe soap pushes the plungers 19 back along the length of the tubes into the positions shown. in Figures 1 The plungers 19 come to rest atthe far ends of the tubes, being held in this position by stops 20 pro vided at the ends of the tubes. This method of filling thetubes is important in insuring that the tubes will be completely filled and willnot contain air bubbles which will appear in the finished soap product. The pressure of the soap requiredto slide plungers 19 along the tubes insures that the tube will be completely filled with soap as far as the plunger, the advancing face of the soap being perpendicular to the length of the tube and filling the entire section of the tube. As

, the plunger moves along, it cleans the tube of water and air so that the entiretube on the soap inlet side of the plunger is filled full of hot liquid soap. j

After the apparatushas operated to rotate a bank of tubes out of filling position, the freshly fill-ed tubes of soap come under the action of coolingwater sprays 21. During the step-by-step rotation of the tube banks, each bank of tubes is subjected to the action of the cooling water sprays during the first half of the revolution, after which the tube bank becomes immersed in the cooling water bath maintained in tank 22. as shown. Continued rotation causes the bank of tubes to pass around through the water bath until it cooling action in twenty-two of the twentyfour positions assumed during each revolution of the aparatus. Partitions 13 may be provided between the respective'tube banks, as shown in Figure3, to shield the tubes from the action of the Water sprays when the tubes are infilling position. l/Vhile the cooling action, as here shown, consists in subjecting the soap-containing tubes to the action of a water spray and a cooling bath, itwill be understood that each of the tubes 1 can be provided with a water jacket through which cooling water is circulated, or each bank of tubes may be provided with a water jacket so that the water circulating through each jacket cools all of the tubes in one bank. Theprovision of water jackets for the tubes is perhaps somewhat preferable in that there is no opportunity for water to be sprayed or splashed about, and jacketing of the tubes does not objectionably increase the cost of the apparatus.

The solidified rods of soap are discharged from the tubes 1 after the respective banks of filled tubes have rotated about through the water sprays and the cooling bath and have come into the position indicated at 23 in Figures 3 and 4. The back end of each of the tubes 1 is provided with a small pipe 24 (see Figures 1 and 2) which connects to a radial hole 25 provided in the trunnion portion 9 of the rotating tube plate 3. The pipes 24, extending from the several tubes of each bank, connect into trunnion 9 along the same radial line, as shown, so that trunnion 9 is provided with a plurality of rows of holes 25, the number of rows being equal to the total number of tube banks in the apparatus and the numberof holes in each row being equal to the number of tubes in each bank. The stub shaft 10 upon which trunnion 9 rotates is provided with a plurality of passages 26 equal in number to the number of tubes in each bank. The passages 26 enter the stub shaft 10 at its outer end and are then turned at right angles so that passages 26 can come into register respectively with the row of holes 24; in the trunnion portion 9 as the apparatus moves intoits respective positions. A liquid, for instance water, is supplied to the respective passages 26 through the medium of pipe connections 27 by a pump 28. The pump 28 here shown is a quintuplex pump, each of the five cylinders of the pump supplying one of the passages 26. A single pump supplying all of W the passages could be provided, but it is positively to each of the passages 26 at sub- .7

stantially the same rate.

LIA

When a bank of tubes has rotated into: the extruding position, the pipes 24 and the holes 25 through the trunnion which pertain to that particular bank of tubes come into register. with water passages 26 inrwhich water is maintained under pressure by means of pump 28. Water under pressure, therefore, enters the respective tubes 24 and passes intO. the tubes 1 behind the plungers 19 provided in the tubes. The pressure of the water moves the plungers along the length of the. tubes and thus extrudes the respective solidified rods of soap from the several tubes of the bank.- The solidified soap is extruded from the tubes at the filling ends thereof. The principal object of supplying water separately to the respective tubes of the bank by means of the pump arrangement above do scribed is to insure simultaneous and uni form extrusion of soap from all of the tubes of the bank. r

The extruded lengths of soap may be discharged ontoany suitable table or surface.- In the apparatus here shown a travelling belt 29 is provided for'receiving the extruded lengths of soap. The belt 29 is preferably driven through the medium of driving connections and gearing indicated generally at 30 and is therefore timed with respect to the rate of rotation of the tube banks 1. Pump 28 is driven through the medium of a driving connection indicated at 31 and is also timed relative to the rate of rotation of the tube banks 1. The driving relation between pump 28 and the soap receiving belt 29 is preferably such that belt 29 travels at the same speed or slightly faster than the rate at which the pump 28 efiects extrusion of the solidified bars of soap from the tube banks 1. The solidified lengths of soap may be conveyed to cutting machines or the like, as desired, on belt 29.

After the tube bank has rotated out of its discharge position 23, it comes next into fillin g position 17, whereupon thefilling operation takes place and the cycle of the process is repeated as above described. Upon first being rotated into filling position 17 the tubes 1 are full of water and the plungers 19 within the respective tubes are all pushed tightly against the stops at the inlet ends of the tubes. lVhen the tube bank moves into filling position, the water pipes 24 connected with the respective tubes of the bank come into register with drain pipe 32, also provided within stub shaft 10 (Figures Qand 3). The pressure of the hot liquid soap being loaded into the tubes moves plungers 19 back along the length of the tubes, as above described, thus forcing the water out of the tubes through drain pipe 32, from whence it may be passed to waste or returned to water supply tank 33 for subsequent use.

From the above it will be noted that the operation of the apparatus is entirely automatio. The operator has merely to watch the apparatus to see that everything is working properly. One operator can well attend to several machines, thus making the labor cost practically negligible. positions of the .tube banks during a single rotation of the apparatus, one position is utilized for filling of the tubes, one position for extrusion of the solidified soap from the tubes, and the other twenty-two positions are 7,

available for active cooling and solidification of the soap in the tubes. This particularly high time-eificiency of the apparatus is important in obtaining a large production from apparatus of moderate size. A small electric 1 motor furnishes all of the power required for complete automatic operation of the apparatusf One bank of tubes is loaded and one bank of tubes is discharged at every interval in the movement of the apparatus. after the apparatus is in regular operation, solidified soap from an entire tube bank is discharged at each position assumed by the tube banks; e. g., every three or four minutes.

It will be appreciated that the diameter of the apparatus, thelength and size of tubes, and the number of tubes per bank may be increased as desired with corresponding in crease in production.

It has been found that certain conditions must be satisfied in order to produce perfect lengths of molded soap which are fullsize, uniform, smooth, unshrunken, free from air Of the twenty-four Thus,

bubbles,-and which are of proper texture and soap results. This action takes place whether thesoap is molded in large bodies, as for instance in framing, in elongated bodies, as for instance tubes, orin small sizes, as for instance molds corresponding in size to individual cakes, The present invention avoids ll There are a number of such shrinkage of the soap and provides for M the production of full-sized uniform cakes which constitute a high grade commercial article. I have found that, if the hot liquid pp soap is loaded into the tubes 1 under sufficient ,1?

pressure, if then the tubes are sealed off tightly as above described to prevent admission or egress of soap and to prevent ingress of air, a well-formed unshrunken bar of solidified soap can be produced, This is a probably due to the fact that the pressure exerted upon the hot liquid soap during loading actually compresses the soap into a volume sufficiently smaller than the Volume which it would occupy at normal pressure to tubes.

compensate for the normal decrease in volume resulting from shrinkageJ It is therefore an object of the invention to provide for loading the tubes with hot liquid soap under pressure 5 sufiiciently high sothat, although'the supply of hot liquidsoaptothe molds iscom'p'letely shut off before the molds are subjected to cooling action, thefinished solidified soap will nevertheless completely fill the respective t has beenfound that this result can be obtained by loading pressures of approxt mately fifteen pounds per square inch above atmospheric." It hasbeen found that sealing off of the" tube in such manner as to prevent ingress of airduring the solidification period is important.

If, however, the soap does have a tendency to shrink dueto insufiicientpressure during loading; etc., exclusion of air from thesoap 2 molds tends to produce a full-sized unshrunlc en cake of soap, probably because anytendency to shrink inside of the air-tight mold tends to correspondingly reduce the pressure within the mold and thus to check the shrinking action. The invention therefore contemplates the production of full-sized unshrunken bars of soap by sealing off the soap filled mold, as described.

The preferred operation is to loadthe hot liquid soap under such pressure that, when the soap is extruded after solidification, it does not show any evidence of shrinkage and also doesnot show any evidence of expansion as, for instance, bythe solidified rod of soap tending to creep out of the end of the tube before extruding pressure is applied, as will happen if an excessively high pressure has been used in thefilling operation. The limits of loading pressure which will give 1 satisfactory results are not sufficiently criti-- cal as to make operation difficult. For instance, pressures ranging from say tento thirty pounds per square inch above atmospheric have given satisfactory results. Higher pressureswill also give reasonably satisfactory results, it being understood that increase in pressure tends to induce expansion of the soap after pressure is released while excessively low pressures tend to produce a slight concavity in the sides of the molded cakes even though a substantially airtight seal on the mold is obtained. c Excessive variations of pressure also will affect the specific gravity. of the finished soap to some extent; the specific gravity being increased with increasing pressure and vice versa.

From the above it will be noted that the present invention avoids shrinkage of the soap without causing any hot liquid soap to flow into the mold after the cooling-action has been instituted, and without pressing or inoldingthe soap after it has become wholly or partly solidified forthe, purpose of correcting objectionable shape characteristics .65 of the soap. This feature of thelinvertion hot or warm water.

is important in obtaining a finished soap proceeded to a substantial extent, the soap will not be of perfecttexture and internal structure. Soap treated in this way exhibits visible fracture lines which ordinarily appear as lines or rings in a cut section of the solidified soap. These deficiencies in internal structure are probably produced by relative movement within the body of the soap after congealing of the soap has set in. These fractures give the soap a non-homogeneous structuralcharacteristic and tend to cause the finished cake of soap to break apart or flake off at these fracture lines. Soap produced according to the process of this invention is'free from this objection; it presents a smooth uniform texture throughout its body.

Another feature which has been found to be of particular importance is the temperature of the tubes or molds during loading of the soap; It has been found that, for the best results, the tubes-must be warmed prior to filling with hot liquid soap so that the soap which comes into contact with the walls of the tube does not begin to congeal or solidify before the tube is completely loaded.

If this condition is not observed, the above described ring formation and like difficulties in texture are apparent in the finished soap, particularly in the outer portions of the cake. In=the embodimentof the invention herein, this warming of the tubes is accomplished by extruding the soap by means of Since the warm water is expelled from the tubes-during the same operation by which loading of the tubes is effected, the tubes can readily be heated to any desired temperature for the filling operation. The temperature of water employed for this purpose is preferably approximately that of the soap being loaded, for example, 150 to 2009B. It is merely necessary, however, to have the water sufficiently warm so that the soap will not become chilled when it touches the walls of the tubes and will therefore not begin to set or congeal before the tube is completely loaded. Thus, water temperatures considerably lower than those specified above can be used, the lower limit being that at which imperfections in texture of the soap near theouter edges of the finished cake appear. It willbe noted that the heating of the tubes is accomplished without introducing an extra step in the operation. It will be understood that, where the tubes 1 are jacketed, the tubes could be warmed by circulating warm water through the jacket, or.

in various other ways. V y It has also been found that the best texture and structure of the soap is produced by relatively slow cooling. In preferred operation, the cooling operation occupies about an hour and a half. Ordinary tap water is, generally speaking, a satisfactory cooling medium. The cooling water which is applied to the tubes immediately after they are filled may, if desired, be somewhat warmer f than that applied toward the end of the cooling operation. For instance, the water circulated against the freshly filled tubes may conveniently be water which has already been somewhat warmed by contact with other tubes. Fresh cooling water is supplied to the water pan 22 asindicated at 34, sothat the coolest water comes in contact with the tubes which are farthest removed from the filling position and which are about to move into the extruding position. Cooling of the soap as contemplated by this invention, by a cool but not excessively cold medium, provides a product which is superior from the standpoint of texture and internal structure as compared with a product wherein the cooling was carried out by subjecting the molds to a cold medium of refrigerating temperature.

The soap is extruded from the tubes in cold condition. Application of heat to the soap or mold before extrusion softens the soap and impairs the texture and appearance of the soap surface. Extruding plungers 19 are of substantial length and may be made of insulating material or may be provided with insulating rings for the purpose of preventing transfer of heat from the warm water behind the plunger to such an extent as might soften or impair the rear end of the rod of soap being extruded. The extrusion of the soap by means of the plunger followed by warm water serves further to clean the tube and insures that the fresh soap is loaded into a smooth clean tube free from any soap from the preceding charge.

The soap product produced by the process herein described is a continuous rod of soap of the same cross-section as the inside of the tube. The soap has a smooth attractive appearing outer surface which gives it a finished appearance more desirable than the surface of cakes which are obtained by slabbing and cutting framed soap. The surface of the soap is formed so that it may be handled immediately without marring. It has been found that the soap may be cut into lengths immediately after extrusion and may be wrapped and packed immediately without any drying treatmentas is commonly practiced in present commercial operation. Even when wrapped and packed immediately, the soap does not sweat in the wrappers. It does not stain the wrappers to any substantial extent, and in this respect is e a particular improvement over ordinary framed soaps even when they have been subjected to a drying operation after slabbing and cutting. The soap does not stick to the wrappers.

The invention is defined in the following claims. The invention contemplates particularly the new process described above and the apparatus for conducting the process. The invention further contemplates the product produced. Certain changes and said mold to prevent ingress of air during cooling of the soap, and then cooling the soap in said mold to effect solidification thereof, whereby an unshrunken block of soap of the same shape and size as the interior ofthe mold is obtained.

2. The method of molding soap which comprises filling a mold with hot liquid soap, warming the said mold prior to filling to a temperature sufficient to prevent congealing of the soap which comes into contact therewith, sealing the mold to prevent escape of soap and to prevent further admission of soap, and then cooling the mold and the soap contained therein, whereby no relative and substantial bodily movement within the mass of soap occurs after solidification of any portion thereof has taken place.

3. The method of molding soap which comprises warming a mold to a temperature sufficiently high so that hot liquid soap coming into contact with the walls of the mold will not become chilled and partially solidified, filling the said warmed mold with hot liquid soap, compressing the said hot liquid soap into the mold so that the volume occupied by the hot liquid soap is not larger than the normal volume which will be occupied by said soap at atmospheric pressure after cooling and solidification, and then effecting cooling and solidification of said soap by the application of a cooling medium to said mold whereby the cooled solidified soap will completely fill said mold.

4 The method of forming cakes of soap which comprises molding hot liquid soap into an elongated form and of cross-section corresponding to one cross-section of the desired soap cakes, applying sufficient pressure to the hot liquid soap so that the length of soap after being solidified is not shrunken, discontinuing the supply of liquid soap before cooling thereof has progressed to any substantial extent, cooling the soap to effect solidification of the soap, and cutting said rod of soap into lengths to form cakes of soap of desired size.

5. The method of molding soap which comprises warming a mold to a temperature sufficient to prevent congealing of soap which comes into contact therewith, filling said warmed mold with hot liquid soap, applying a sufficient pressure to the hot liquid soap in the mold during filling so that the soap, when solidified, will completely fill said mold, shutting off the supply of hot liquid soap to said mold and sealing the mold against leakage, cooling the soap in said mold by applying thereto a cooling medium of temperature well below the solidificationtemperature of the soap but not of refrigeratingtemperature, permitting the mold and the soap contained therein to remainunder the action of said cooling medium until solidification of the soap is completed, and thereafter expelling the solidified soap from the mold.

6. Apparatus for the manufacture of soap which comprises an elongatedmold, an inlet for admission of hot liquid soap to said mold, a plunger within said mold which, when the mold is in filling position, lies adjacent the soap inlet end of the mold, means for introducing hot liquid soap into said mold and causing it to move said plunger along the length of the mold until the mold is filled, whereby the mold is completely filled with soap free from air bubbles, means for cooling the mold and the soap contained therein to effect solidification of the soap, means for applying hydraulic pressure to said plunger to effect removal of the soap from the mold after solidification thereof, the plunger and the solidified rod of soap being forced along the length of the mold by the hydraulic pres sure applying medium which also passes into and along the length of the mold, and means for warming the hydraulic pressure applying medium sufficiently to heat said mold to a temperature above the solidification temperature of the soap, whereby the mold can be filled with its next succeeding charge of hot liquid soap without solidification of any portion of the soap until after the mold is completely filled.

7. Apparatus for making cakes of soap which comprises an elongated mold of cross section corresponding to one cross-section of the desired soap cakes, a plunger operating along the length of the mold to effect discharge of solidified soap therefrom, means for filling the mold with hot liquid soap against the action of said plunger to thereby insure complete filling of the mold with soap free from objectionable air bubbles, means for applying sufficient pressure to the hot liquid soap being admitted to said mold to move the said plunger back along the length of the mold and to compress the hot liquid soap sufficiently after the plunger reaches the extremity of its movement so that the soap, when solidified, will completely fill said mold, discontinuing the supply of hot liquid soap to the mold before any solidification of soap in the mold takes place, sealing the mold to prevent escape of soap or ingress of air, cooling the mold and the soap contained,

therein to effect solidification of the soap, means for applying a hydraulic pressure to said plunger after solidification of the soap is complete to thereby discharge the solidified soap from the mold, the hydraulic pressure applying medium being water heated to a temperature sufiicient to warm the mold above the solidification temperature of the soap, whereby the said warm water in extruding the solidified length of soap heats the mold sufiiciently to avoid congealing of soap when the next succeedin charge of hot liquid soap is introduced into the mold.

8. Apparatus for the manufacture of soap which comprises a plurality of batteries of elongated molds, means for filling abattery of said molds with hot liquidsoap under pressure sufficient so that the solidified soap subsequently discharged from the mold shows no evidence of shrinkage, all of the molds of the battery being filled substantially 9 simultaneously, means for successively moving the respective batteries of molds into filling position and during the same movement sealing off the battery of molds just filled to prevent escape of soap therefrom, to pre vent further admission of soap thereto, and to prevent ingress of air to the mold during solidification of the soap contained therein, means for applying a cooling medium to the successive batteries of molds shortly after they leave the filling position, and means for discharging cooled and solidified soap from a battery of molds simultaneously with each filling of another battery of molds, and automatic means for effecting intermittent movement of the respective batteries of molds past the said soap filling and soap discharging means. 7

9. The method of molding soap which comprises filling the mold with hot liquid soap, warming the said mold prior to filling to a temperature sufficient to prevent congealing of the soap which comes into contact with the mold during filling thereof, and then cooling the mold and the soap contained therein by bringing into heat transferring relation therewith a cooling medium of temperature lower than that of the soap being cooled but not of such low temperature as to be in the nature of a refrigerant. V

In testimony whereof I aflix my si nature.

WALTER A. HAR ER.

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