Buzz
Modern divers utilize rebreathers to reuse their air supply, eliminating bubble production. Steve Woods Photography / Getty Images/Image SourceMain Highlights
- Rebreathers enable divers to reuse exhaled air by filtering out carbon dioxide and replenishing oxygen, allowing for bubble-free underwater respiration.
- Three main rebreather types exist: oxygen, semi-closed circuit, and closed-circuit, each designed for specific diving depths and oxygen toxicity thresholds.
- Benefits include enhanced gas efficiency, reduced weight as nitrogen is unnecessary, shorter decompression periods, and increased stealth due to negligible bubble release.
In traditional scuba equipment, inhaling through the mouthpiece delivers fresh air from the tank strapped to your back. Exhaling releases air through the regulator, creating bubbles in the water. A rebreather, however, is a scuba device that recycles your breathable air, eliminating bubble production. To achieve this, the device must perform the following functions:
- Eliminate exhaled carbon dioxide. This is done using a cannister filled with sodium hydroxide (Sofnolime). The carbon dioxide (gas) reacts with sodium hydroxide and calcium hydroxide, forming calcium carbonate (solid).
- Replenish consumed oxygen. Small tanks containing pure oxygen or mixed gases (nitrogen-oxygen or helium-oxygen) introduce fresh oxygen into the breathing cycle.
- Regulate oxygen levels in the breathing loop. Solid-state oxygen sensors measure the partial pressure of oxygen in the loop, sending data to a microprocessor that manages the oxygen-delivery system.
There are three main types of rebreathers: oxygen, semi-closed circuit, and closed circuit. Oxygen rebreathers rely solely on a cylinder of pure oxygen, restricting them to "no decompression" depths and posing a risk of oxygen toxicity. Semi-closed circuit rebreathers utilize gas mixtures, allowing divers to reach greater depths without the danger of oxygen toxicity. Closed-circuit rebreathers carry both pure oxygen and mixed gases, differing from semi-closed systems in how they maintain oxygen concentration.
Rebreathers offer several benefits compared to traditional scuba gear:
- Improved gas efficiency: Traditional scuba systems waste oxygen since divers don't use all the oxygen in the inhaled air. Rebreathers only replace the oxygen consumed, minimizing gas waste.
- Reduced weight: Compressed air consists of 78 percent nitrogen, making up most of the weight in traditional scuba systems. Rebreathers eliminate the need for nitrogen, resulting in lighter equipment for the same oxygen supply.
- Simpler decompression: With minimal nitrogen in the system, which contributes to "the bends," decompression is less complex, allowing divers to stay underwater longer than with traditional scuba.
- Enhanced stealth: Rebreathers produce little to no bubbles, ensuring minimal disturbance to marine life and keeping the diver's presence concealed.
Rebreathers are regarded as high-tech scuba equipment, initially created and primarily utilized by military forces, including the U.S. Navy SEALs.
While advanced and professional divers can operate rebreathers, thorough training is highly advised. Moreover, these devices come with a hefty price tag, reaching up to $15,000.
Continue exploring for additional resources on underwater breathing and diving adventures.
