FUGATION JAMES 0.MALONEY UNIVERSITY OF K A N S A S , LAWRENCE, K A N ,
I
*
HE principal activities in the field of centrifugatio continue to be in the area of app1i:ation rather than along fundamental lines. In an attempt to discover what work is being done in the 001leges and universities of the country, a qu 83 departments of chemical engineering, work done in the past 10-year period, the activities now under way, and the equipment available for centrifugal studies. Of the 83 departments receiving the questionnaire, 50 replied Forty-two have done no work in the past 10 years and 41 do not contemplate doing any in the foreseeable future. The distribution of the equipment by schools and type is found in Table 1
by two different methods for particle size determinations and found they gave the same results. The studiw were made in an International centrifuge with titanium dioxide as the settling material. A special sector celI was developed by the authors. Schachman (24) extended and modified the earlier theoretical equations for the Sharples centrifuge. Employing bentonite, a calibration factor for the unit was obtained which could then be used for padicle si5e analysis of other substances. Good agreement was found between the behavior of tobacco mosaic virus in the Sharples unit and the ultracentrifuge. Theoretical considerations were made of the effect of convection due to ternperature differences in the bowl. It was found, however, that the experimental results could be better predicted on the basis of convection-free equations. The theory developed on the equilibrium behavior of high-polymer solutions in a centrifugal field (34)has now been verified (56),and the results indicate that the sedimentation-equilibrium method offers a satisfactory means For the characterization of high polymers. An elementary t r e a t ment of centrifugal sedimentation has been presented by Hebb and Smith (18). A study of the accuracy of the Svedberg ultracentrifuge for particle size determinations has h e n reported
T
TABLEI. CENTRIFUGAL EQUIPMENT IN COLLEGES A UNIVERSITIES
No. of Schooh Having One unit 16 ;~%;~;$t;~ 1;
Four units Five units six units Total unite
$ 2 67
Types of Equipment
~
~
Unite type
De Lava1basket Fietoher &ne type type International Equipment Co., basket type Rochester, basket type Sharples supercentrifuge Sharples uper-D-Canter Tolhurst %asket t pe Miscelladeous sma%-scaleunits
~
~
8 10 I
~
F
~
(4).
13 1
Centrifuges developing high fields are being used in the separation and study of glycolytic enzymes (16),lipoproteins (8), myosin ($9,SO), mouse liver cell nuclei (19), and latex (3). A method for the determination of the particle sise of colloids from sedimentation data obtained with the Sharples superis described by Loukomsky and O’Brien (18). An excellent general description of types of centrifugals and fields of application has been written by Smith @e). This article covers dl types of industrial equipment with which the reviewer ie and can be used by those teaching centgugation as a good qualitative introduction to the field. This article together those of lM&wdt (7) on centrifugal costs and Smith (28)
11
6
5F‘-
Work that has been colnpleted in the past lo-year period by the 60 schools is found in Table 11, and activities now under way are listed in Table 111. F~~~this information the conclusion can be drawn that t,he field of centrifugation is wide open for study. I t is also probably t m e that the unit operation of centrifugation receives only scantattention in the undergraduate as well as the graduate curriculum. Consequently, graduates from our engineering schools are familiar only in a
IONS IN COLLEGES AND UNIVERSITIES ON TION DURING PERIOD 1939-49
*
1
obtaining information on new applications and developments and estimating the quantity of fundamental data these organizations have, It was believed that personal discussions might result in publication of fundamental information so badly needed. Several companies, as a result of visits, have agreed to consider seriously publication of certain test data. Without exception, the centrifugal companies deplored the lack of understanding of this unit operation on the part of engineers. Several offered to consider the possibility of furnishing experimente to the schools illustrating what they felt were the fundamental d m ~ t e r i s t i c s of such equipment.
University of Alabama
gztez$;
;if&~*a
Date 194 1949 1949 1948-9 1948
Michigan College of Mining 19.17 and Technology Pratt Institute 1944 West Virginia University 1947
TABLE 111.
INVESTIGATIONS IN COLLEQES AND UNIVERSTTIRS ON CENTRIFUGATION AT PRESENT TIME
Bohool Cornel1 University University of Florida
THEORETICAL D E V E L O P M E N T S
The major activities in theoretical developments are being carried forward by the groups involved in the determination of particle molecular weight, or separation of biological materials. By far the most sophisticated treatment is that of Robison and Martin (B), who developed several mathematical approximations for particle size determinations. They (83) subsequently applied the theory to experimental data obtained
Northeastern University University of North Dakota Pratt Institute West Virginia University
as
Title Continuous disoharge basket Drying rate in a basket centrifugal Washing in a basket centrifugal Recovery of fate from press wastes Draining rates and centrifugal bibliography Effect of volume of solvent on efficiencymaterials of solute recovery from inert Solvent extraction of oil from acorne Correlation of several operating variables in dewatering by centrifugation
Title Drainin rates Removaf: of slag-forming ash from heavy fuel oil Gas centrifugation Particle size distribution Recovery of solids from effluent from potato flour plants Dewatering of aodium sulfate crystals Extraction of soluble protein from potatoea Preparation of chemically purified oilseed proteins using centrifugals Dewatering by centrifugation
26
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
on centrifugal selection can serve as a foundation for intelligent selection and cost estimation. Hebb and Smith (12) present cross-sectional vieas of several of the more common types of ccentrifugals and also sizes of certain units. Vilbrandt (55) has increased his treatment of rentrifugals in the new edition of his text. A series of photographs is used to illustrate a description of a iiew centrifuge capable of exerting forces of 260,000 times gravity (2). Smith (QY)in a recent article has described the new applicaLions of equipment, and listed the equipment announced during the past 2 years. The operation of a self-discharging centrifugal has been described (37). Centrifugals have been employed for the removal of tannery waste sludge from spent vegetable tanning liquors (21). Difficulties in the separation of high viscosity sugar solutions from sugar crystals have been reported by Hruska (13). The removal of quick settling sludges resulting from the dry-lime treatment of waste pickle liquors has been achieved with centrituges (16). Wastes from whisky distilling sources have been concentrated by centrifugation and evaporation (24). Ambler ( 1 ) has described the use of centrifugals in the separation of oils in steel plants. Centrifuges have been used for the clarification of heer a r d wort (56). RECENT PATENTS
A number of patents have been issued recently. I n the reviewer’s opinion it is essentially impossible to evaluate the significance of such patents unless the complete patent picture is known. Consequently they are merely tabulated by title. Centrifugal amalgamator ( 9 ) Centrifuge bowl with discharge valves for separating sludge trom liquids (10) Centrifugal filter for separating crystalline sugar from mother liquor ( 6 ) Centrifugal separator of coal fines from heavy iinliurities ( 11 ) Centrifugal separator for separating solids from liquid and discharging them upwardly by force of acquired velocity (26) Centrifuge for separctting whey from cheese constituents (31) Clarifying mash (52) Continuous-discharge centrifugal ore concentratoi (6) Uewaxing oils ( 1 7 ) Drying green fodder (20)
Vol. 42, No. 1
LITERATURE CITED
(1) Ambler, C. M., I r o n Steel Engr., 26, No. 6,108-16 (1949). (2) Anon., Product Eng., 20, No. 2 , 9 2 4 (1949). (3) Bie, G. J. vander, Mededeel. Nederland. I n d . Inst. Rubberonrlrrzoek Buitenaorg, No. 48,1-12 (1948) (4) Cecil, R., and Ogston, A. G., Biochem. J.,43,692-8 (1948). (5) Chisholm, G. G., Can. Patent 454,703 (Feb. 22, 1949). 1 Delius, H. A., U. S.Patent 2,464,440 (March 15,1949). Eckhardt, H., Chem. Eng., 54, No. 5,121-3 (1947). ~
Gofman, J. W.. Lindmen. F. T.. an3 Elliot. H.. J. Bbl. @ h e m . 179, 973-9 (1949).
Hamilton, T., U. S. Patent 2,472,475 (June 7, 1949). Hanno, T. V., Ibid., 2,467,742 (April 19,1949). Harrineton, J., Ibid., $,454,798 (Nov. 30, 1948). Hebb, M. H., and Smith, F. H., in “Encyclopedia of Chernioal Technology,” Vol. 3, pp. 601-21, New York, Intermiewe Publishers, 1949. Hruska, J., L i s t y Cukrogar. 64, 233-7 (1948). Klassen, C. W., and Troemper, A. P.,Proc. 3rd Ind. Wabte Conf., Purdue Univ., Eng. Bull. E x t e n s i o n Ser. 64, 153 64 (1947).
Le Page, G. A., and Schiieider, W. C., J . Biol. Chem., 176, 1b24 7 (1948).
Lewis, C. J., I r o n A g e , 163, No. 3,48-53 (1949). Lindgren, H. O., U. S. Patent 2,439,434 (April 13, 1948). Loukomsky, S.A., and O’Brien, 8. J., Am. Soe. Testing Matrraa h , Proc., 46, 1437-50 (1947). Nash, C. W., Can. Pharm. J.,8 2 , 2 5 1 4 (1949). Nieuwenhuyzen, J. L. von, Dutch Patent 63,290 (May 16,1949), Reuning, H. T., Sewage Works Eng., 20, 133 (1949). Robison, II. E., and Martin, S. W., J . Phys. & Colloid p h m 52, 854-81 (1948). Ibid., 53, 860-86 (1949).
Sehachman, H. K., Ibid., 52, 1034-45 (1948). Sharples, L. P., U. 8. Patent 2,446,559 (Aug. 10, 1948)” Smith, J . C., C h e m . Inds., 65,357 -64 (1949) a
Ibid., pp. 519-20. Smith, J. C., IND.ENC.@HEM., 39,474-9 (1947). Snellman, 0..and Erdos. T.. Biochem. et Biophw. . . A c t a , 2. 6.W-9 (1948).
Snellman, O., and Tenow, M., Ibid., 2, 384-8 (1948). Strezynski, G. J., U. S.Patent 2,4611,129 (Feb. 8, 1949). Strohmaier, A. J., and Lovell, C. L., Ihid., 2,461,938 (Feb.
16,.
1949).
Vilbrandt, F. C., “Chemieal Engineering Plant Design,” gp. 388 40, Now York, McGraw-Hill Book Co., 1949. Wales, M., J . Phys. &: Colloid Chem., 52, 235-48 (1948). Wales. M.. Williams. J. W.. Thomoson. J. 0.. and Ewart. K. I3 . Ibid., 52, 983-8 (1948).
Windisch, F., Brauuelt, 1947, 233-7. Zambrovski, V. A., Sakharnaya Prom., 22, No. 12. 22-5
[1048).
C O N S U L T I N G ENGINEER, M A P L E W O O D , N. 1.
HE postwar period, up to the present, has emphasized diversity in the application of crushing and grinding equipment in oontrast to the development of new devices. Modification of current types of machines to meet new conditions and to incorporate new knoxledge continued through the year. Although the drastic departures embodied in the conical ball mill, ball ring mills, and jet mills are developments of earlier years, it is to be expected that new major changes will appear in the near future (8). It has been reiterated in previous reviews (68) that the tools of measurement of fineness quality are an essential to marked progress in this field. The past year has shown considerable advances in the application of present, tools and more reliable data are being made available today on the performance of these grinding machines. Much still remains t o be done in that regard, chiefly the elimination of unreliable or meaningless data.
During the past year, “Industrial Rheology and Rheologica Structures” (28), by the late Henry Green, was published; the final touches on this work were done by Ruth Weltman who had cooperated closeJy with him for more than 10 years. Although this work deals with solid-fluid systems and particularly with viscosity functions, part I11 comprising chapters 12 through 16 deals with the particle as a basis of the rheological structure. Little is given 11s to methods with the exception of the microscope and the electron microscope. The philosophy of the writer that a true knowledge of the particle is essential to a full understanding of the subject is equally applicable in the fields of crushing and grinding. Sedimentation methods (26, 3 6 ) still tend to hold the spotlight because they yield distribution data with a minimum of effort. Commercial equipment in this field includes the Fisher-Dotts ail-
