(05-06-08) Buceo Profundo Dive Center show us the most sold closed-circuit rebreathers Inspiration and Evolution. They are made by Ambient Pressure Diving; they have been on the market for a long time and they are the reference point for silent diving.

     The Inspiration / Evolution are electronic or manual CCR (closed-circuit rebreather), certified by the EEC to -50 m. with air and to -100 m. with heliox.

     Since 1911 nitrox has been used for diving, though only on a professional level. In the 90’s it starts to be used in recreational diving. Thanks to this trend tables as reliable as those used for air have been created.

     Breathing from a rebreather is easy and rewarding, as simple as breathing in a bag but with some adjustments: first, as all this kind of devices, there is a circuit to direct the gas (a breathing loop). There are two unidirectional valves in the mouthpiece and two breathing bags or counter lungs that are next to our chest when we put on the device.

     Attached to the loop there is at least one valve allowing injection of gases. These lungs are connected by a trachea that also connects them to the canister or filter for purification of CO2. In the canister it is the main difference between rebreathers and other devices: three oxygen sensors of high accuracy that are responsible for analyzing the gas at all times. These solid-state oxygen sensors monitor the partial pressure of oxygen in the breathing loop and send this information to a microprocessor that controls the oxygen-delivery system.

everything controled by two computers

      Everything is controlled by two computers: a master and a slave that can be alternated and where we can manipulate our partial pressure during the dive. They will warn us of any failure in the system using visual and acoustic cues (a strong and unpleasant beep).

     Inspiration has 3 l. bottles, and Evolution 2 l. bottles. One bottle has oxygen and the other one has thinner, which may be air, Nitrox, Trimix or Heliox. If the constant partial pressure of oxygen is 1.3 while diving, we can extend the dive to unsuspected limits even with nitrox, since with nitrox we only have the greatest partial pressure in the maximum depth, while the RAC keeps the constant partial pressure at all depths.