How Does an Oxygen Rebreather Work?

Oxygen rebreathers are modern scuba gear designed to recirculate oxygen you exhale and separate it from the carbon dioxide to supply more oxygen to a diver. The ability to breathe more efficiently and stay under water longer than you could with traditional scuba gear are advantages you gain with oxygen rebreathers.

  1. Types of Oxygen Rebreathers

    • As of May 2008 there were three types of oxygen rebreathers: closed circuit, semi-closed and oxygen.

      Oxygen systems use pure oxygen as the singular source of breathing gas and are generally known to pose the risk of oxygen intoxication due to their limitation with decompression depths.

      Semi-closed units utilize tanks holding oxygen mixed with either nitrogen or helium to remove the risk of oxygen intoxication, thereby enabling divers to dive to greater depths.

      Closed-circuit rebreathers combine the technology of the other two using pure oxygen, oxygen and various other gases.

    The Function of Oxygen Rebreathers

    • Oxygen rebreathers are designed to expand the capabilities of professional divers by increasing dive times and improving the efficiency of oxygen and gas usage. The ability to remove carbon dioxide from exhaled air and maintain economical balance of fresh oxygen and mixing gases are how oxygen rebreathers eliminate the bubbles commonly seen while diving and increase the depth and duration of a dive.

    Risks of Oxygen Rebreather Diving

    • Sudden blackouts have been known to occur due to hypoxia caused by low partial pressure of oxygen in the loop. The loop is the portion of the supply line where oxygen and gases travel to and from your exhale and the oxygen and mixing gas supply tanks. This is also known as shallow water blackout.

      Seizures due to oxygen toxicity, also caused by too high a partial pressure of oxygen in the loop, are another risk.

      Excessive carbon dioxide can cause disorientation, headaches, panic and hyperventilation.

      You must breath continuously as the habit of air conservation from traditional units does not apply with rebreathers. Rebreathers require constant breathing to keep the gas flowing and mixing with the oxygen.

    Advantages of Oxygen Rebreathers

    • Increased gas efficiency is the single most significant advantage with oxygen rebreather use. In conventional scuba gear, as the diver exhales, most of the oxygen exits the lungs unused. With rebreathers, the oxygen leaving the lungs during exhale is recirculated and reused continuously.

      Closed circuit rebreathers have a distinct advantage by allowing divers to dive deeper and longer without the risk of oxygen intoxication or decompression risks often found in other scuba gear.

      Conventional scuba gear has it's tell tale signs with bubbles which create noise. Oxygen rebreathers eliminate this concern by eliminating bubbles completely. This enables divers to study marine life more closely and to go undetected while observing marine life that would otherwise sense a diver's presence and disappear into the distance.

    Disadvantages of Oxygen Rebreathers

    • When compared with traditional scuba diving gear, oxygen rebreathers are much more expensive and possess a higher degree of difficulty of operation and maintenance. Additionally, reliability has been known to be an issue.

      Diagnosing and fixing a problem at depth is a major concern for divers using oxygen rebreathers as they are difficult to trouble shoot if not functioning properly. Unlike conventional scuba, when a problem arises the diver knows what to do and generally speaking, can maintain breathing while fixing it. With oxygen rebreathers there are several more elements to run through the process of elimination as you attempt to trouble shoot. A rebreather's reliance on electronics to manage the oxygen control system is the main reason for its reputation of being unreliable.