US 3764114 A
A mass of soap ready for forming cakes of soap therefrom is produced in continuous operation by conveying starting materials as conventionally used for the production of soap through a continuous treatment line including a screw extruder with at least two parallel screws, the screw elements of which are in mesh and coact with the inner wall of the casing of the extruder. The screws are divided into sections or groups of screw elements the pitch of which increases in downstream direction. Sections of kneading discs are interposed between selected sections of screw elements to effect kneading and homogenization of the materials. The starting materials are fed into the casing at one end thereof and additives are added through casing openings as the mixture of the starting materials is being conveyed in the casing toward the discharge port thereof. The mixture is discharged from the casing as finished soap of formable consistency.
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Description (OCR text may contain errors)
United States Patent [191 Oclcer Oct. 9, 1973 PROCESS FOR CONTINUOUSLY PRODUCING SOAP AND DEVICE FOR CARRYING OUT THE PROCESS  Inventor: HerbertOcker, Leonberg, Germany  As signee Werner8zPfleiderer,Stuttgart- Fleuerbach, Germany 22 Filed: Sept. 7, 1971 21 Appl. No.: 178,026
 Foreign Application Priority Data Sept. 12, 1970 Germany 20 45 272.6
 References Cited UNITED STATES PATENTS 4/1963 Street 425/204 2/1967 Boden ..l ..259/192 Primary Examiner-Robert W. 'Jenkins AttorneyFrederick E. Hane et al.
[5 7] ABSTRACT A mass of soap ready for forming cakes of soap therefrom is produced in continuous operation by conveying starting materials as conventionally used for the production of soap through a continuous treatment line including a screw extruder with at least two parallel screws, the screw elements of which are in mesh and coact with the inner wall of the casing of the extruder. The screws are divided into sections or groups of screw elements the pitch of which increases in downstream direction. Sections of kneading discs are interposed between selected sections of screw elements to effect kneading and homogenization of the materials. The starting materials are fed into the casing at one end thereof and additives are added through casing openings as the mixture of the starting materials is being conveyed in the casing toward the discharge port thereof. The mixture is discharged from the casing as finished soap of formable consistency.
There is also disclosed an installation for carrying out the afore-described method of producing soap in continuous operation.
5 Claims, 2 Drawing Figures PATENIEDUET m 3.764.114
HERBERT OCKER PROCESS FOR CONTINUOUSLY PRODUCING SOAP AND DEVICE FOR CARRYING OUT THE PROCESS The invention relates to a method of producing soap in continuous operation and to a device including screw elements for carrying out the method.
BACKGROUND In years past and to a certain extent also even at the present time the production of soap is effected by means of soapifying fats with soda lye in boilers. The fatty acids and the lye are then reacted with the addition of steam and the glycerine formedby the soapification is washed out with brine. The production of soap by this process requires a considerable period of time just for reaching the soapification stage and the subsequent process stages that are required to perfect the soap necessitate further and very long periods of time and also complex and expensive installations.
There are known several processes for producing soap which are more or less improved over the aforedescribed initial method, but even these improved processes have similar disadvantages. Very frequently they do not produce fully satisfactory high quality soap.
The industry has attempted for many years to develop processes for producing soap in continuous operation without requiring long periods of time and costly installations. There is known, for instance, a process for continually producing soap in which fatty acid as one of the starting materials is first partly soapified to a selected percentage by reacting fatty acid with soapifying agents such as sodium carbonate, potassium carbonate; etc. Subsequently, the partly soapified fatty acid if fully soapified with soda lye having a suitably selected concentration. The soap is now washed in at least two stages with an electrolyte solution and the electrolyte content in the soap is reduced by washing it with diluted soda lye or potash vlye. The alkali excess is neutralized with fatty acid and the fatty acid content is adjusted for a selected value. If necessary, the percentage of fatty acid may be concentrated to a selected value.
The starting materials are fed in this process into a two-stage soapification reactor. An installation for carrying out the just-described method operates continuously for this purpose; comprises a continous treatment line which includes, among many other devices, screw elements which act as agitators at selected points of the installation and also serve to convey a product through specific selected treatment zones. j I
The described process of continuously producing soap and an installationfor carrying out the process are described, for instance, in published German Patent Application No. 1,069,319. The disadvantage of the described continuously operating process and of the installation therefor is that the construction costs of the installation are very high and that it requires a very large space, especially if soapis to be produced in large quantities. Moreover, the time required for carrying out the process is still much higher than desirable.
The same disadvantages are present when the production of soap is carried to a preliminary stage by one of the known methods, and the thus obtained unfinished product is then kneaded, homogenized and upgraded in separate screw extruders, as has also been proposed.
THE INVENTION known, is less complex and also less expensive to construct and to maintain than comparable installations as heretofore known.
SUMMARY OF THE INVENTION The aforepointed out objects, features and advantages and other objects, features and advantages which will be pointed out hereinafter and are set forth in the appended claims constituting part of the invention, are obtained by feeding starting material as suitable and conventional for the manufacture of soap into a continuous treatment line through which the material is continuously and forcibly conveyed and in which it is subjected continuously to the action of screw elements rotating crosswise to the length of the treatment line. As the material passes through the treatment line it is intially subjected to presoapification and is gradually fully soapified so that when it leaves the treatment line it constitutes finished soap of pliable and thus formable consistency.
The process of the invention is advantageously carried out in a screw extruder, the casing of which in cludes at its ends a feed port and a discharge port respectively, and if desired also intermediate ports for degasing the material as it passes through the extruder and for feeding additivies such as fragrant essences or dyes into the material at selected zones.
The extruder as used for carrying out the process of the invention includes at least two screws which are parallel to each other and to the axis of the casing. The screws are in mesh and also coact with the inner wall of the casing, at least one of the two screws extending through the entire length of the casing. However, it is generally preferable that both screws extend through the length, of the casing.
According to one aspect of the invention, the two screws are unidirectionally rotated as tests have shown that the use of two screws extending through the entire length of the casing and rotated in the same direction results in minimal installation costs and optimal production results.
It has been also found particularly advantageous to provide in the inlet zone of the extruder, that is in the zone in which preliminary or presoapification of the starting material occurs, two meshing screw sections with self-cleaning profiles. This zone including the mesh and self-cleaning screw sections is preferably directly followed in downstream direction by a zone including kneading discs in tight engagement as the provision of a section including kneading discs facilitates the basic reaction. Moreover, compacting of the mixture of the starting materials and further intimate mixing and homogenizing thereof in later stages of the process, can be effected within a short period of time by the provision of one or more sections including kneading discs.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION In the accompanying drawing, an installation for carrying out the process of the invention is shown by way of illustration and not by way of limitation.
In the drawing:
FIG. 1 is a diagrammatic lengthwise sectional view of the installation; and
FIG. 2 is a cross-section of FIG. 1 on an enlarged scale.
Referring now to the figures more in detail, only those components of the installation are shown that are essential for the understanding of the invention.
The installation as exemplified comprises a casing I. This casing may be as is customary and as it is indicated be constructed of several sections suitably secured to each other but for the purpose of the process of the in vention it should be visualized as constituting a continuous casing. The casing and the devices associated therewith are supported by a suitable foundation structure indicated at 16. The casing of the extruder includes, as it is conventional, ducts 17 for circulating a heating system and/or a cooling medium through the casing. Two extruder screws 2 and 2a are rotatably mounted within the casing and unidirectionally driven by conventional drive means indicated at 15. Both screws extend across the length of the casing but in some cases one of the screws may be shorter than the other. The screw elements are in mesh with each other and the outer peripheral diameters of the screw elements are such that they coact with the inner wall of the casing as it is clearly indicated in FIGS. 1 and 2.
The screw elements of the conveyor screws are subdivided for structural and also procedural reasons into sections such as, for instance, sections 2b and 26. As it is indicated in FIG. 1, the screw elements haveidifferently pitched screw turns, either within the sections or with reference to other sections. Sectionalized extruder screws as shown in the screw extruder of FIG. 1 are well known and conventional in the art; they are constructed by sliding the screw elements on a shaft and keying the screw elements thereon. FIG. 2 shows such shafts 4 and screw sections keyed thereon.
FIG. 1 further shows supply containers such as container 5 for a suitable soapifying agent such as soda or potash (potassium carbonate) and container 6 for fatty acids. The materials in containers 5 and 6 are fed via surge tanks 5a and 5b and metering devices 7 of conventional design to a feed port 8 in casing l. The aforereferred to pitch variations of the screw elements in the different sections of the screws are selected in accordance with the specific starting materials that are used and also in accordance with the location of the screw elements within, as seen in the downstream direction. As it is evident, the processing of the starting materials to finished soap occurs in successive stages and these stages control and are controlled by the selected configurations of the screw elements. FIG. 1 further shows sections of kneading discs 3 interposed between sections of screw elements. The finished product is discharged from the extruder casing through a feed port continued by a pipe 14.
The basic reaction of the soapifying process occurs already within the feed-in zone of the extruder, that is,
the zone at feed port 8. The screw elements will positvely and continually carry the materials as they are being converted to soap toward the discharge end of the casing. The first or feed zone which includes sections 2b and 2c, terminates approximately at the location of the first section of kneading discs 3 as seen in the downstream direction. The screw elements in the feed zone preferably have self-cleaning tightly meshing profiles. Such screw elements, of course, arewell known in the art and do not constitute part of the invention.
The mixture is subjected to a first compacting action and a particularly effective homogenization while passing the first section of kneading discs 3. Just downstream of this section released volatile components are discharged through a degasing port 9.
In the feed zone, that is, between port 8 and the first section of kneading discs 3 additives as conventionally used in the production of soap may be added in metered quantities. A conventional metering device suitable for the purpose is indicated at 11. Especially after passing the first section of kneading disc 3, the mixture acquires low viscosity, and gradually becomes a mass of more or less plastic or formable consistency. If desired, further additives can be fed into the mixture by devices such as device 11 and also additional degasing ports of the type indicated at 9 may be provided. The material after passing a second section of kneading discs 3 as seen in downstream direction is further degased by a degasing port 10. After passing this port the product has already the character of curd or grain soap. Moreover, in this stage of the process, an excess of alkaline as may be present in the soap is neutralized. However, it should be noted that the structure of the screw extruder as described for carrying out the process according to the invention eliminates reaction excesses to the extent this is possible'within the parameter of the process.
Refining of the mass now in the form of curd or grain soap to fine or high quality soap occurs in the zones of the extruder downstream of degasing port 10. Shortly after the mass has passed this port and also the second section of kneading discs, metered quantities of fragance essences and dyeing agents may be added to the mass of soap by means of a conventional metering device 13. A feed port 12 serves to feed into the mass quantitatively high grade waste such as accumulates when the still soft finished soap as discharged at the discharge end of the extruder casing is pressed into the form of cakes of soap and cut or trimmed as part of this operation.
Downstream of the addition of such high quality waste the mass of soap is further homogenized by a final section of kneading discs 3a. After passing this section, the discharge screw section 20 delivers the now finished product to the outlet of the extruder. This outlet may include a suitably shaped die or nozzle, (not shown).
The finished refined soap is fed through a pipe 14. At the outlet end of this pipe a conventional shaping and cutting assembly 19 cuts and shapes the finished but still soft soap mass as it emerges from pipe 14 into cakes of soap which then may be packaged in the usual manner.
While the invention has been described in detail with respect to a certain now preferred example and embodiment of the invention, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.
What is claimed is:
l. A method of producing soap in continuous operation from a mixture of starting materials of the kind described, said method comprising the steps of:
providing a continuous treatment line in the form of a screw extruder comprising an elongate casing having at one end a feed port and at the other end a discharge port and including a pair of conveyor screws rotary within the casing parallel to the axis thereof and having differently pitched screw elements, said screws coacting with each other and with the inner casing wall transverse of the lengthwise axis thereof, the wall of the casing intermediate said ports thereof including lengthwise spaced degasing openings, feed means for feeding the mixture of starting materials into the casing through said feed port and further feed means disposed intermediate the ports in the casing for feeding additives into the casing;
feeding the mixture into the casing through the feed port therein;
continuously subjecting the mixture to the action of the screw elements as the mixture is being conveyed toward the discharge port for converting the mixture into a pliable mass of soap;
degasing the mixture as it passes said degasing openings; and v feeding additives into the casing and thus to the mixture as the latter passes said further feed means.
2. A device for producing soap in continuous operation from a mixture of starting materials of the kind described, said device comprising:
a screw extruder including an elongate casing having at one end a feed port and at the other end a discharge port, at least one degasing opening intermediate said ports, two shafts rotary within the casing parallel to the axis thereof, screw elements secured to said shafts for rotation in unison therewith, said screw elements being divided into sections and constituting a continuous conveyor screw on each shaft, the screw elements on at least one shaft extending along substantially the length of the casing and including screw elements of different pitch for varying the action of the screw elements upon the mixture as the same passes the respective group of screw elements, the section of screw elements adjacent to the feed port constituting a feed-in section of the extruder, the screw elements in said section being in mesh and having self-cleaning profiles; a first section interposed between the downstream end of said feed-in section and the next adjacent downstream section of screw elements, the section of screw elements adjacent to the discharge port constituting a discharge section, the screw elements in said discharge section having a uniform pitch, and a second section of kneading discs interposed between the upstream end of said discharge section and the downstream end of the next adjacent section of screw elements.
3. The device according to claim-2 wherein drive means rotate the shafts unidirectionally, and thescrew elements on the shafts are in mesh.
4. The device according to claim 2 wherein the pitch of the screw elements in certain of said sections is steeper toward said discharge port.
5. The device according to claim 2 wherein a degasing opening in the casing wall is disposed downstream of said first section of kneading discs and communicates with the screw elements in the next adjacent downstream section.