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Low-Cost Immersion Heaters for Water Baths Immersion hrarers avnilahle frum sricntilir supply huu.ws range in w i t frmn ahout 5:1 I to ovpr $IIXI, with 3 typical cast uf h n r t $60 'I'hr low~st-costmmwrsiun hearrrs orr urdmary hghr lrulbi. They haw a tnsc rrsponie time but are limited to reli~ti%rly Ion u,aitnpes 1111,111 ahour LOU w,, haw mmimal irnmprswn depth, aud prrsrnt rhc mmor hazard ofbrraking. For higher wattages, gceaterdurahility, and greater immersion depths, we use commercially available hot water immersion heaters. These heaters cost about $7 from suppliers such as W. W. Grainger. Immersion lengths range from about 7 to 14 in. and wattages from 750 to 4500 a t 240 volts. Since we wire these heaters for 120 volt use, the actual wattages are one-fourth the nominal wattage and the heaters should last indefinitely. The heaters that we use are made by the Dayton Electric Manufacturing Ca. of Chicago. We mount the heaters by drillinga clearance hole in a 2-in. PVC pipe end cap (schedule 40), sealing the heaters in place with the washer supplied and a truseal nut (Flick-Ready Co.), and then cement to the cap whatever length of PVC pipe is needed. We use a &in. length of pipe and can then mount the assembly i n a water bath with the joint immersed. T o protect the electrical connections from moisture the open end of the pipe can be covered with another end cap or a rubber stopper.
Rubin Battlno Wright State University
Dayton. OH 45435
Volume 61
Number 6
June 1964
563
