| abstract |
Apparatus provide gas sensing operations such as for oxygen concentration sensing with an oxygen concentrator. In some versions, gas concentration sensing apparatus with pressure, temperature and/or mass flow sensors measure characteristics of a gas mixture in a vessel. A controller of the apparatus may estimate concentration of a constituent gas in the gas mixture as a function of the measured pressure, temperature and mass flow rate. In some versions, the sensing apparatus may measure a thermal conductivity of enriched gas, and, with a controller, estimate concentration of argon in the enriched gas from the thermal conductivity. The controller may estimate concentration of oxygen in the enriched gas from the concentration of argon. In some versions, an oxygen concentrator may have a mass flow sensor and a controller configured to trigger bolus delivery and/or measure oxygen concentration, and/or regulate bolus profile based on signals from the mass flow sensor. |