Fig. 1
From: Comprehensive structural model for the evaluation of HME humidification properties
Structural model for assessment of HME performance. \(\:{{m}_{i}^{ent}}_{}^{}\) mass entering the HME during inspiration (position 1, measurement of hb and \(\:{V}_{insp}\)), \(\:{m}^{st}\) mass reversibly stored in HME, HME performance, \(\:{m}_{i}^{ext}\) mass leaving the HME during inspiration and entering the dead space (VD), \(\:{m}_{e}^{ent}\) mass leaving the dead space and entering the HME during expiration (water load), \(\:{m}^{ret}\) mass leaving the dead space during inspiration and entering the humidifier, (position 2, measurement of mb and Vmb), \(\:{m}^{sup}\) mass leaving the humidifier during expiration (position 3, pre-set target humidity), \(\:{m}_{e}^{ext}\) mass leaving the HME during expiration (position 4, measurement of wo and Vexp). \(\:{m}^{add}={m}_{e}^{ext}-{m}_{i}^{ent}\) mass added in the humidifier, \(\:eta=\eta\:=\frac{{m}^{st}}{{{m}_{e}^{ent}-m}_{i}^{ent\:\:}}\) HME efficiency. For additional information see text.
