US2039605A - Starch manufacturing process - Google Patents

Description

May 5, 1936- A. PELTZER, JR 'n 2,039,605

STARCH MANUFACTURING PROCESS Filed July 31, 1933 ATTORN Patented May 5, 1936 UNITED STATES PATENT oFFicE SVTARCH MANUFACTURING PROCESS Albert Peltzer, Jr., Palo Alto, Calif., assigner Merco Centrifugal Separator Co. Ltd., San Francisco, Calif., a corporation of California Application July 31, 1933, SerialNo. 682,909 'z claims. (01.'12'1-69)l This invention applies generally to systems for the manufacture of starch from materials like corn, where the corn orI like material is disintegrated and components such as germs, hulls,

vfibrous material and gluten, are removed from the desired starch.

It is an object of the invention to provide an improved process or method for the removal of gluten from wet starch bearing feed material such as is produced in systems of the above character, thereby making possible the manufacture of starch having a relatively low protein content. In carrying out my invention a step of flotation separation is utilized, and this step is made effective by the prior removal of fibrous material. Furthermore foaming or frothing is accomplished in a separating step prior to flotation, and simultaneously withremoval of fibrous material.

Further objects and features of the invention will appear from the following description in which the preferred embodiments of the invention are set forth in detailin conjunction with the accompanying drawing.

' Referring to the drawing:

Figure 1 is a diagrammatic view showing one way in which my process may be carried out in practice.

Fig. 2 is a diagrammatic view showing a modiiied manner for carrying out the process.

'Ihe process or method of the present invention in its preferred form can be outlined briefly as comprising subjecting wet starch bearing material to centrifugal separation, in such a manner that fibrous material therein passes out with the gluten overflow, and the starch underow is foamed or frothed to a substantial degree. Further removal of gluten from this starch underilow is then accomplished by flotation.

The process can be better understood after a brief description of the drawing. Referring first to Fig. 1, I have indicated a centrifuge of the type disclosed in copending application Serial No. 586,773, filed January 13, 1932. A centrifuge of this character is characterized by the fact that it operates continuously, and a portion of the underflow is continually returned to the centrifuge bowl adjacent the periphery thereof. Thus, in the diagrammatic representation the centriiuge bowl I I is provided with a separating chamber I2 into which the wet starch bearing feed ma- 'terial is introduced as indicated by line I3. A starch underflow discharges from peripheral nozzles I4 and is received by volute I6, while a gluten overflow discharges over the wier I1. A major part of the material discharged from the nozzles I 4, after further removalof gluten therefrom as will be presently explained, is ycontinuously returned back into the centrifuge chamber as indicated by line I8. The material returned to the centrifuge rotor by way of line I8 is delivered 5 into the bowl at a point adjacent the periphery thereof, thru an impeller 20.

Wash liquor can be introduced into the rotor together with the return, as indicated byline I9. The use of a ltrate obtained rom otherV points 10 in the'wet starch system is desirable, since such a ltrate promotes foaming.

With a centrifuge of the type described above, Where the feed material consists chiefly of starch together with gluten and fibrous material (com- 15 monly termed mill starch), the overiiow consists of gluten together with fibrous material from the feed. The underflow received by the volute I6 consists of starch which still retains a part of the gluten from the feed, but which will be sub'- 20 i 'underow will be foamed or frothed to a substantial extent. Thisv foaming action is attributed 25 to the entrance of air or other gases with the feed, and to introduction of air into the return circuit because of `letting into volute I8, and the beating and violent agitation to which the material is subjected. I have found that the foamed 30 or frothed condition of the underflow facilitates a subsequent separation oi' remaining gluten from the starch, by flotation. Thus as shown in Fig. 1, the starch underflow removed from volute IS is introduced into a vessel 22 by way oi pipe 2|. 35 Gluten separated from the starch in vessel 22 is floated off over wier 23, while the starch is removed by way of stand pipe 2d and outflow box 26. A rotating skimmer 2l can be employed axljacent to wier 23, to secure more effective removal 4o of the gluten. A continuous return of starch to the centrifuge is afforded by pipe Ilia, which is an extension of line I8. Suitable bathing can be provided for the discharge from pipe 2| and the inlet end of pipe I8a, as illustrated. 45

The removal of gluten from the underflow by flotation has been found to be highly eective. The substantial absence of fibrous material in the centrifuge underflow eliminates a middle draw-off from the notation step, thus making 50 possible continuous operation with eflicient separation of gluten, and avoiding starch losses and practical difficulties which a draw-od of midlings would occasion. Since in this instance the step of notation is interposed in the return ir- 55 cuit,'the material returned by4 way of line I8 is 'largely freed of gluten, and is substantially un-v In'Fig. 2 I have shown a modified manner lin which the step of flotation is associated with the centrifugal separation. In this case the return of a major part of the underflow received by volute Il occurs directly within the centrifuge machine' -by way'of line Il, while a part of this foamed underflow is diverted thru pipe 2l for otation. Such an arrangement does not subject the underflow to flotation before being returned to the centrifuge, but it enables variations in the underflow to be immediately reflected in variations in the return, thus affording better inherent stability.

I claim:

l. In a process of the character ,described for the production of starch from wet starch bear-` ing feed material containing gluten and fibrous s,

material, the steps of centrifugally separating the feed into a starch underflow and a gluten overow containing the majority of the brous material from the feed, yand then subjecting the underow t flotation for the further removal of gluten.

2. In a process of the character described for the production of starch from wet starch bearing feed material containing gluten, the steps of removing a gluten overilow from the feed material by centrifugal separation while simultaneously frothing the starch underflow, and then separating further gluten from the frothed starch underilow by flotation.

3. In a process of the character described for the production of starch from starch `bearing feed material containing gluten and fibrous material, the steps of centrifugally separating the feed into afrothed starch underflow and a gluten overow containing the majority of the fibrous material from the feed, and subjecting the frothed underflow to flotation for the further removal of gluten.

4. In a process of the character described for the production of starch from wet starch bearing' feed material containing gluten and fibrous .materiaL the stepsof centrifugally separating trifugal separation, and separating further glutenA from the underflow by flotation.

5. In a process of the character described for the production of starch from'wet starch bearing feed material containing gluteny and fibrous material, the steps of separating the feed into a starch underflow and a gluten overflow containlng a. majority :of the fibrous material, by centrifuging, said centrifuging being characterized by the continuous return of a portion of the underilowback to the zone of separation, and

being also characterized by a frothing of the underflow, and effecting further removal of gluten from the underflow by flotation.

6. In a process of the character` described for effecting Separation between starch and gluten in wet starch bearing material-like mill starch, centrifuging ythe mill starch to form a frothed starch underflow and a gluten overflow, directly delivering the frothed underflow to a body of the same where the frothed component thereof'is floatedv oil', continuously returning defrothed starch from' said body to said centrifuging operation, and removing' starch from said body for nnai delivery at a rate substantially less than the 1 rate of return. y Y

7. In a .processof the character described for thetreatment of mill starch or like starch bearing material containing ilbrous material together with starch' and gluten, centrifuging .the mill starch to form a. frothed starch 'underflow and la gluten overflow which contains substantially all of the fibrous material, directly delivering the frothed 4underflow to abody of the same where the frothed gluten component thereof is floated off, continuously returning defrothed starch from said bodyto said centrifuging operation, and removing starch from saidv body for final delivery at a rate substantially less than the rate of return. 1

ALBERT PELTZER, Jn.

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