Compact Reciprocating Stirrer Assembly. E. E. Fleck and J. E. Nickels, Koppers Co., Inc., Multiple Fellowship on Tar Synthetics, Mellon Institute, Pittsburgh, Pa.
construction of the freezing point apparatus of Glasgow, TStreiff, and Rossini [ J . Research Natl. Bur. Standards,
monk motion that is transmitted to the stirrer. The amplitude of the reciprocating motion is readily adjusted by securing the Scotch yoke bearing screw in the desired tapped hole (three shown) of the rotating flange fastened to the geared motor shaft. The motor is easily replaced by another when it is desirable to change the frequency of oscillation
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35, 355 (1945)l was modified by the introduction of a simple, Compact source of reciprocating motion, comprising a small, geared induction motor (120 r.p.m., Model SG-15, UerkelKorff Gear Co., Chicago, Ill.) attached to a Scotch yoke which converts the angular motion of the motor to simple linear har-
This reciprocating motion stirrer assembly is suitable for other purposes such as determination of cloud points, solubilities, and aniline points. The complete assembly, with stirrer, was constructed to specifications by the Research Appliance Company, Pittsburgh, Pa. -
Sublimation Apparatus. Kathan L. Smith, S a v a l Research Laboratory, Kashington 20, D. C.
SPACER
J
of sublimation, particularly under reduced presTsure,method is. readily . adaptable for the purification of many solid HE
compounds. Compounds,that are exceedingly difficult to purify satisfactorily by recrystallization are frequently obtained in excellent purity by this method. An apparatus for sublimation, which greatly decreases the difficulty encountered n ith the clogging of the vacuum outlet, is illustrated in the accompanying sectional drawing. The substance to be sublimed is placed in the flask and heated, under the vacuum of an oil pump, by a wax bath, Glas-col, or metal bath a t a temperature that causes it to sublime. The sublimate condenses in the core, and the labyrinth formed by the removable center tube minimizes the tendency to clog the vacuum outlet. The apparatus is disassembled a t the completion of the sublimation process by detaching the flask and vacuum adapter
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from the labyrinth, and removing the center retaining tube. The sublimate is then easily recovered from the inner core. The assembly is also useful t19 a drying (vacuum) apparatus. The material to be dried is placed in the inner core and the drying agent retained in the flask. The heat of an infrared lamp is applied to the labyrinth chamber while the system is under vacuum. 1252
