BTPS Correction for Ceramic Flow Sensor: Results

BTPS Correction for Ceramic Flow Sensor: ResultsFigure 3 shows the results for experiment 1 or the percent difference between room air and air heated-humidified for FEVi vs the order in which the maneuvers were performed. The ten consecutive FVC maneuvers for each ATS waveform are connected by a line. For each successive FVC maneuver, the percent difference between room and heated air decreases, particularly for waveforms with larger volumes (ATS waveforms 1 and 2) read more buy birth control. Lower percent differences between room and heated air correspond to a smaller BTPS correction factor being required for BTPS correction. Note that for wave form 4 (FVC=1.5L), the magnitude of the percent difference remains greater than approximately 2 percent even after ten consecutive maneuvers have been performed.
Exit air temperature (placement of temperature sensor shown in Fig 2) at the end of each simulated FVC maneuver was measured and found to increase with each successive maneuver in a manner essentially the same as shown in Figure 3 for the percent difference in FEVi. This increase in exit air temperature is most likely due to warming of the flow sensor’s ceramic element with each successive maneuver. With the warming of the ceramic element, there is a corresponding decrease in the amount of heat removed from the air as it passes through the flow sensor. Figure 4 shows the results for experiment 2 or the percent difference between room air and air heated-humidified for FEVi vs the order in which the maneuvers were performed using waveform 1 (FVC=6 L). The lines in this figure connect identical waiting times between successive maneuvers. Six different waiting times were used in this experiment. In addition to the effect of maneuver order shown in Figure 3, Figure 4 shows the percent difference was related to the time interval between successive maneuvers.

Figure-3

Figure 3. Percent difference in FEVi obtained using room air and heated-humidified air vs the order in which the maneuver was performed, using the first four ATS standard waveforms. Symbols represent different waveforms with different FVCs.

Figure-4

Figure 4. Percent difference in FEVi obtained using room air and heated-humidified air vs the maneuver number for six different time intervals between successive maneuvers (<1 min, 2 min, 5 min, 10 min, 15 min, and 20 min) using ATS standard waveform number 1. Sensor flushed with room air and allowed to cool between each time-interval series (connected points).

This entry was posted in BTPS Correction and tagged air temperature, btps correction, ceramic element.