System for simulating metabolic consumption of oxygen

A system for simulating the metabolic consumption of oxygen contained in a breathable gas supplied by a breathing apparatus, said system comprising:

• a variable volume chamber that is operated cyclically wherein said chamber is operating in one of a vacuum mode to increase volume of said chamber and a pump mode to decrease volume of said chamber;
• valve means coupled between said breathing apparatus and said chamber for defining a first flow path therethrough during said vacuum mode, said first flow path allowing said breathable gas to be drawn into said chamber;
• a source of hydrogen gas coupled to said chamber;
• a source of carbon dioxide gas coupled to said chamber;
• means for introducing said hydrogen gas and said carbon dioxide gas into said chamber to mix with said breathable gas during said vacuum mode to form an exhaust gas, wherein said exhaust gas includes hydrogen and oxygen, wherein said hydrogen gas is introduced in an amount sufficient to react with an amount of said oxygen in said exhaust gas equivalent to that used by a human during a selected level of activity, and wherein said carbon dioxide gas is introduced in an amount equivalent to that provided by a metabolic respiratory quotient associated with said level of activity;
• said valve means defining a second flow path therethrough during said pump mode, said second flow path allowing said exhaust gas to be expelled from said chamber;
• and
• a catalyst coupled to said valve means for receiving said exhaust gas during said pump mode, said catalyst causing a reaction between said hydrogen and said oxygen in said exhaust gas wherein simulated human exhalation is generated.

A method of simulating the metabolic consumption of oxygen contained in a breathable gas supplied by a breathing apparatus, said method comprising the steps of:

• providing a variable volume chamber capable of cyclic operation in one of a vacuum mode to increase volume of said chamber and a pump mode to decrease volume of said chamber;
• directing said breathable gas into said chamber during said vacuum mode;
• introducing hydrogen gas and carbon dioxide gas into said chamber to mix with said breathable gas during said vacuum mode to form an exhaust gas, wherein said exhaust gas includes hydrogen and oxygen, wherein said hydrogen gas is introduced in an amount sufficient to react with an amount of said oxygen in said exhaust gas equivalent to that used by a human during a selected level of activity, and wherein said carbon dioxide gas is introduced in an amount equivalent to that provided by a metabolic respiratory quotient associated with said level of activity;
• providing a catalyst capable of causing a reaction between said hydrogen and said oxygen in said exhaust gas;
• and
• directing said exhaust gas from said chamber to said catalyst during said pump mode wherein simulated human exhalation is generated.