A Safe, Inexpensive Heat Source for Undergraduate Laboratories We wish to report the development of an efficient, low-cost electrical heating device for use in undergraduate laboratories. This heating unit has been used by the authors a t The University of Texas a t Austin in a full program of undergraduate organic chemistry including distillation of materials such as acetophenone (bp 202.3T), methyl benzoate (bp 195.5T), and nitrobenzene (bp 210.U°C) and Thiele tube melting point determinations. In addilion, the rate of heating may he reeulllsted ~.. with mecision adeauato far fractional distillation of mixtures such as benzene-toluene. Tl~iql . ~ ~ : u~n i~t i w d w s ttw n.njor p r ~ h l v n ~ tvcwntrrcd s 1" pr m i d t ~ q a he31 w w w for undergraduallr tml..bmner.i. All wmponents of the unit are resistant to water and steam corrosion, and t,he inslallrttion does not interfere wilh the normal operation of the steam cone. This allows interchangeable use of electrical and steam heat. These units have been in continuous use since September, 1971, and no failures of the heating element, control switch, or steam cone have occurred. The entire heating unit consists of an Ineoloy heating element rated a t 515 W which is controlled by a variable input switch and uses 110 V AC line voltage. The coil can be installed in existing steam cones with bulkhead-type fittings, thus sealing the unit against steam leakage. The eloctricsl connections were made to fit 8. standard appliance plug leading to a control box Additional ins~llationfor the coil was provided by a transite eauirmed - .. with sn indicator lisht. ring.' The authors have found this heatine device to be com~letelv " satisfactorv in nrovidine an inexpensive, durable, and very efficient heat source for undergraduate laboratories. Introductory orientation to enable the student to use the apparalus is minimal, and the unit requires virtually
-
-
THE UNIVERSITY O P TEXAS A T AUSTIN AUSTIN,78712
.
" .
E. J. BURRHNICK, R. M. ROHERTS, S. A. MONTI,U. L. MCELWEQ, and J. C. GILIIERT
Volume 49, Number 9, September 1972
/
623
