Återandningssystem

Återandningssystem, often translated as rebreather systems, are devices that allow a diver to re-breathe exhaled gas. This is in contrast to open-circuit scuba, where exhaled gas is released into the surrounding water. Rebreathers work by scrubbing exhaled carbon dioxide using a chemical absorbent and then adding oxygen to the remaining gas mixture, which is then re-inhaled by the diver. This recirculation of gas significantly increases the efficiency of gas usage, allowing for much longer dive times compared to traditional scuba gear.

There are several types of rebreather systems, broadly categorized into semi-closed circuit rebreathers (SCR) and fully closed circuit rebreathers (CCR). SCRs allow a portion of the exhaled gas to be vented and replaced with a continuous flow of new gas. CCRs, on the other hand, recycle virtually all of the exhaled gas. Rebreathers can use various breathing gases, including air, nitrox, or trimix (a mixture of helium, nitrogen, and oxygen), depending on the depth and duration of the dive.

The primary advantage of rebreathers is their extended endurance. By recycling gas, divers can stay underwater for significantly longer periods. Another benefit is the reduced bubble footprint, making them ideal for wildlife observation and technical diving where discretion is important. However, rebreathers are more complex than open-circuit scuba and require specialized training and meticulous maintenance due to the potential for critical equipment failures. They also typically have a higher initial cost and ongoing running expenses.