Journal of Applied Physiology, Vol 44, Issue 6 981-985, Copyright © 1978 by American Physiological Society
A gas-stream heater to control local skin temperature under evaporative sweat capsules
K. K. Kraning, E. G. Schibli, S. T. Momii and E. A. Merrick
A compact 4-W gas-stream heater for use with ventilated sweating capsules
is described. The heating element is constructed from two modified 75-omega
power resistors connected in parallel and contained in the capsule gas
inlet tube. Heater power is controlled with integrated circuits which
compare the output of a thermocouple, measuring either capsule skin or air
temperature, with a predetermined target temperature. The unit responds
fairly slowly to sudden large changes in target temperature, but once a
steady state is achieved, maintains target temperature levels despite
changes in evaporative heat loss. The device is well suited for studies in
which local skin temperature or capsule air temperature must be elevated
and clamped while the effects of other local stimuli or central
thermoregulatory activity are studied, and in studies where the skin
temperature effect on transepidermal water loss must be controlled.
