Breathing apparatus

A method of reducing heat generated in a breathing apparatus used in an irrespirable atmosphere comprising a high pressure oxygen source provided with reducing valve means presettable to give a continuous high sustained constant flow rate of oxygen from the source in the range of 4 to 30 l/min, personal gas supply means to which the flow of oxygen is supplied, said gas supply means having an inhalation section with an inhalation valve and an exhalation section with an exhalation valve, a regenerative section connected to the exhalation section for absorbing carbon dioxide from exhaled air and a breathing bag connected to the regenerative section so that exhalations which have passed through the regenerative section flow into said bag, the bag having a connection to the inhalation section, and means for exhausting excess gas from the breathing circuit;

• said method comprising
• releasing oxygen from the high pressure source through the reducing valve means pre-set to give a continuous high sustained constant flow rate of oxygen in the range of about 4 to 30 l/min,
• communicating said continuous high sustained constant flow rate of oxygen to the inhalation section of personal gas supply means which supplies breathable gas to a wearer,
• communicating exhaled air from the exhalation section of the personal gas supply means to the regenerative means for absorbing carbon dioxide from said exhaled air,
• communicating carbon dioxide-free air from the regenerative means to the breathing bag,
• communicating air from the breathing bag to the inhalation section of the personal gas supply means, and
• exhausting excess gas through said exhausting means to the atmosphere whereby heat, moisture and carbon dioxide produced by the wearer, which would otherwise increase the heat generated inside the regenerative section, is carried by said high sustained flow of oxygen through said apparatus and exhausted to atmosphere.