Journal of Applied Physiology, Vol 56, Issue 6 1675-1678, Copyright © 1984 by American Physiological Society
Dynamic water vapor and temperature calibration system
F. W. Montague Jr, F. P. Primiano Jr and G. M. Saidel
The objective evaluation of thermal and humidification processes in the
pulmonary system requires accurate dynamic measurements of temperature and
water vapor concentration of a flowing gas mixture. The adequacy of
instruments used for such measurements can only be determined by dynamic
calibration techniques. We have developed a method of producing step
changes in temperature and water vapor content of a gas mixture undergoing
controlled steady flow. The system consists of two reservoirs and a slide
valve that switches a test section between them. The inlet (usually a probe
or catheter tip) of the device to be calibrated is positioned in the test
section. The flow rate through the test section is minimally changed during
the transition between gas from one reservoir to that of the other. The
system has been used to analyze the response of a thermistor and a
respiratory mass spectrometer to changes in gas temperature and water
vapor.
