US Patent 9849313 System to deliver oxygen in an aircraft

The invention relates to a system to deliver a respiratory gas to crew members in a cabin of an aircraft. The system includes at least one respiratory mask, an ambient air inlet for admission of ambient air into the respiratory mask, a source of additional gas, supply lines to transport the additional gas to the respiratory mask, a mixing chamber provided on the supply lines to mix the additional gas with ambient air to supply a respiratory gas corresponding to a mixture of the additional gas and the ambient air to the respiratory mask, regulation system to regulate the additional gas content of the respiratory gas at least partly as a function of the aircraft altitude.