Juha Haapajärvi from Finland is the designer of the
BreatheWise rebreather. The unit is in her 4 th generation development phase
and has some very special features. One of the specials is a principle that
cost me some headache to understand but in fact is very smart. Due to the
nature of dives in the living area of Juha, many dives are made under ice.
Also because most dives are shallow Juha made a very smart solution for a
known problem. When diving a closed circuit rebreather during the ascent de
pO2 will fall. The electronically controlled rebreather tries to
maintain the setpoint and injects oxygen in the loop. This resulting in a
larger gas volume in the loop asking for a valve to be opened. Due to the
bigger impact of depth changes in the 0 - 10 meter zone the unit will not be
diving very stable in this area. Juha exceeded in building an electronic
controlled rebreather that does not maintain a fixed pO2 but a fixed fO2!
The unit has a variable pO2 and a fixed fO2. The buoyancy is more stable in
this way! When the unit reached the preset depth it will switch to a fixed
setpoint and dives as a CC rebreather.