AND ENGINEERING CHEMISTRY
INDUSTRIAL
1162
100
WATERLCVCL
of the tank a t a distance from the shaft of aljoiit half tlie length of the paddle. Since these experiments show that there is a particle iiziiig eRect due to different velocities in the tank, a n ordinary cylindrical tank equipped with a paddle agitator might be used effectively for hydraulic separations. Further investigations along this line are now under n-ap. S A S D C O i i C E S T R A T I O S AS
\\
II
LINCS OF
CLNCLPITRATION
~ ~ U A L
I
I
FIGURE3. HIGH P.ADDLE
To obtain further evidence on the motion of particley under the influence of the agitator, small glass vials were filled with water until their apparent specific gravity was slightly greater than unity. These were placed in the tank and their motion observed while the agitator was turning. There was found t o be little tendency for the vials to rise above the paddle, the motion being outward from the end of the stirrer. This was followed by a downward motion near the wall of the tank, and then an irregular motion as the bottles returned beneath the paddle. Heavier objects, such as fully filled vials, simp117 rolled around the bottoni
Vol. 21, No. 10
IXDESO F
STRElJl
FLOW
Ailthough sand concentration seems to be a measure of the degree of mixing, it probably does not accurately picture the stream lines of the liquid. A given particle of sand is not intimately bound up with a given filament of water. The sand may drop from one stream line to another. depencling on the relative 1.elocities of the two filaments. However, for practical purposes, the lines of sand concerit~ratioii .wm to represent qualitatively the liquid ~clocitiesat various poiiits. The distributioii of sand under the influeuce of tlie paddle agitator is probably some complicated function of particle iize, of the linear velocity of the liquid, of the centrifugal etl‘ect of the stirrer, and perhaps of other variables. S o iiiathematical treatment of the probleni seems poqeihle a t this time. LITERATURE CITED (1) Badger a n d McCabe, “ E l e m e n t s of Chemical Eiiuineering,” McGraw-Hill, 1931. (2) Hixson a n d Crowell, IND. EKG.CHEM.,23,923, 1002, 1160 (1931). (3) Kood, Whittenrore, and Badger, Chem. &. M r t . Eng.. 27, 1176 (1‘322).
RECEIVEDMay 18, 1932
Debarking and Degumming Ramie by Chemical Means Preliminary Report C;.
A
L. CARTERWITH P. 11. HORTOK, Louisiana State University, Baton Rouge, L a
LTHOL-GH ramie hap long been knon 11 aiid sporadiIn the Orient the green wet stalbs are stripped aiid the balk cally discussed as a possible textile fiber, it has never renioved by hand. This material dried is the China grass of assumed a position of importance iii this field. Rela- commerce. Sumerous attempts have been made to perfect tively small quantities of the fiber are consumed in Europe in methods for stripping and debarking by machine. S o the manufacture of specialties, but no expanhion of this field process which has been made public seems to be commercially can be expected until the price of the fiber is materially re- successful The operation of stripping is relatively simple. duced. In the Orient large quantities of the fiber are pro- aiid, if the removal of the bark can be effected by chemical duced in carefully tended sniall plots. harvested, purified, iiieanq, the combined operation. n ill lie much simplified and consumed locally. Only cheap hand labor allows this The wlutinn of the Ijark by cheniical mean-, degumming, and fiber to compete on a price basis with other fillers, and almoqt ~nodiictionof a bleached fiber of high teiide strength con-titUte tlie olijectiT e< to he diqcuiied i l l tliic and forthcoming none is available for export. From the grower’s point of vieii the crop has been attrac- papers. Preliminary stud1 ut +tripping indicated that the hark aiid tive. It propagates from the roots, is free from pests, yield* very heavily, and matures evenly ah straight unforked sterns. fiber bundles can 1,e removed from the -tall\ only n.hen the It should yield readily to mechanical methods of harvesting. g u n i ~are completely wftened by
