To obtain the above values, underwater breathing apparatus TIR/SPACE 40 has a sealed
pressure reducer that reduces the tank pressure from 200 bars to steady 13 bars (as a rule, in
case of a sonic nozzle the intermediate pressure has to be at least double of foreseen pressure at
maximum depth + 20%); in our case the gas originated from the tank, at intermediate pressure
of 13 bars, passes through a sonic titanium nozzle with a calibrated opening that fixes a constant
flow of 9 lt./ (with the 40% of oxygen for the 30 mt./100ft.) or 14 lt (with the 32% of oxygen
for the 40 mt./133 ft.). In case of underwater breathing apparatus for professional use these
parametres will be very different but, in any
case, the flow of the mixture will always
assure a suitable and more than adequate
replacement of oxyigen at any depth.
The reference tecnical standards related
to the CE (European Standard) require
a breathing volume of 3 liters for closed
circuits (EN14143) or of 2,5 liters for
regulators in open circuit (EN250 and/or
EN13949). Underwater breathing apparatus
TIR/SPACE, the only one of its kind in
the world, has no internal bags like all the
other rebreathers on the market, but it has a counterlung with a membrane, which has a 2,5
liters volume and is more than sufficient to satisfy a normal breathing; if one or more very
deep breaths are necessary, for instance in case of breathlessness due to fatigue, a demand
larger than 2,5 liters will be fulfilled by the existing supply mechanics in the counterlung that
will automatically deliver the needed quantity of fresh mixture enriched with oxygen without
limitation and without effort, so that the diver will overcome immediately a possible critical
situation; likewise, the diver will be able to do the cleaning of the counterlung, whenever they
think it necessary, by simply exhaling from the nose or pushing on the center of the membrane.
It is obvious that in all these circumstances the supply mechanics operation will cause a larger
consumption and will penalize the foreseen endurance.
SEMICLOSED CIRCUIT FOR PROFESSIONAL USE
NOTE: we consider it for professional use when it is used under 40 mt./133 ft. and/or when
dives with decompression stops are planned at any depth.
This kind of diving needs wider and more complete knowledge and professionality, even using
Heliox mix too. Therefore it is not part of this informative report and of the normal use of underwater
breathing apparatus TIR/SPACE 40 configurated for recreational use as explained later.
For information we specify that the professional version keeps unchanged the counterlung
body and the technical features before indicated, while automatic mix of gas (Helium-Oxygen
or Helium-Nitrox) and fluxes are directly conditioned by water pressure – a system we have
patented also in USA and Canada. In short, two tanks are used, one containing Oxygen (or
Nitrox) and the other Helium, as well as two pressure reducers and two pertinent titanium sound
nozzles that automatically regulate flux management according to depth. For example, during
the immersion oxygen (or Nitrox) amount decreases and Helium (diluent) amount increases;
on the contrary, during the ascent while depth lowers oxygen (or Nitrox) amount increases and
Helium amount decreases; this way decompression is made possible breathing mixes enriched
with oxygen. Furthermore, in the last 12 meters under the water line(or 20 mt. when Nitrox is
used) the breathable mix is devoid of the diluent (Helium).
