Irving Allan Kaye
Brooklyn College Citv universitv of New York Brooklyn, New York
II
An Improvised Steam Bath
The prospect of equipping our undergraduate organic chemical laboratories with a number of steam baths led us to develop a simple, inexpensive, easily-comtructed heating bath (shown in the accompanying diagram). The apparatus consists of two tin cans; the upper one (the water bath, whose 0.d. and height are 4 and 4.5 inches, respectively) rests securely, with a fairly tight seal, on the lower (the steam hath, whose 0.d. and height are each 4 inches). Two 1.5-in. lengths of 3/8-in.copper tubing are soldered to the steam bath can. I n order to obtain a steam-tight seal between the two cans, the steam hath is constructed from a can of the type which has a top (removed initially with a key) which is used as a friction cover; this type of can is often used t o package coffee,nuts, and fats. Rusting is inhibited by painting the cans. Flasks up t o 300 rnl capacity may he immersed in the water bath; larger vessels may be h a t e d with steam on the other hath. Escaping steam is a hazard when water-sensitive reactions are heated. The steam-heated water hath does not present such a hazard; in addition, it offers a high heat
transfer rate fromthe condensed steam to thewater bath, which reaches its maximum temperature of 91" from room temperature in about 6 min. Bath temperature seems more quickly attained when a vessel is immersed in a heated liquid bath than when heated on a steam bath.' If reactions are to he heated in the bath for long periods, and if the presence of water vapor is objectionable, we have used as hath liquids a 1 :1 mixture of water and ethylene glycol (or a polyethylene glycol). The author wishes to thank the American Can Comvanv - - for a generous gift of their round, type "B," key opened 401 X 405-25 electrolytic tin plate cans which were used in preparing the steam baths. 1
SCAERRER, J. A,, Ind. Eng. C h m . , Anal. Ed., 5.22 (1933).
Volume 41, Number 12, December 1964
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