A Metabolic Simulator for Unmanned Testing of Breathing Apparatuses in Hyperbaric Conditions
| Autor: | Mario Loncar, Åke Larsson, Mikael Gennser, Hans Ornhagen, Oskar Frånberg |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Atmosphere Exposure Chambers
Materials science Respiratory rate Atmospheric pressure Rebreather Diving Respiration Public Health Environmental and Occupational Health chemistry.chemical_element Equipment Design Carbon Dioxide Models Biological Oxygen chemistry Materials Testing Tidal Volume Breathing Humans Limiting oxygen concentration Respiratory exchange ratio Simulation Tidal volume |
| Zdroj: | Aviation, Space, and Environmental Medicine. 85:1139-1144 |
| ISSN: | 0095-6562 |
| DOI: | 10.3357/asem.4047.2014 |
| Popis: | Background A major part of testing of rebreather apparatuses for underwater diving focuses on the oxygen dosage system. Methods A metabolic simulator for testing breathing apparatuses was built and evaluated. Oxygen consumption was achieved through catalytic combustion of propene. With an admixture of carbon dioxide in the propene fuel, the system allowed the respiratory exchange ratio to be set freely within human variability and also made it possible to increase test pressures above the condensation pressure of propene. The system was tested by breathing ambient air in a pressure chamber with oxygen uptake (Vo₂) ranging from 1-4 L · min(-1), tidal volume (VT) from 1-3 L, breathing frequency (f) of 20 and 25 breaths/min, and chamber pressures from 100 to 670 kPa. Results The measured end-tidal oxygen concentration (Fo₂) was compared to calculated end-tidal Fo₂. The largest average difference in end-tidal Fo₂during atmospheric pressure conditions was 0.63%-points with a 0.28%-point average difference during the whole test. During hyperbaric conditions with pressures ranging from 100 to 670 kPa, the largest average difference in Fo₂was 1.68%-points seen during compression from 100 kPa to 400 kPa and the average difference in Fo₂during the whole test was 0.29%-points. Conclusion In combination with a breathing simulator simulating tidal breathing, the system can be used for dynamic continuous testing of breathing equipment with changes in VT, f, Vo2, and pressure. |
| Databáze: | OpenAIRE |
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