What is a rebreather? A rebreather is a type of breathing apparatus used by divers differentiating from others in the market through its ability to recycle the gases you exhale, to be re-used in a continuous flow cycle. If you are a professional diver or a commercial diver then you have no doubt heard of these systems but most likely never used one. Whereas commercial divers usually use a surface supplied diving system in order to work, rebreathers are more often used by technical divers for the freedom of movement and smaller penalties in the way of decompression needed.
The mode of action of a rebreather is based on some basic and simple scientific principles. The rebreather enables you to inhale the air you breathed out instead of releasing it in the form of air bubbles. The rebreather primarily removes the carbon dioxide content of the exhaled air using a small volume of the alkali, sodium hydroxide in the scrubber.
The carbon dioxide is eliminated in the form of solid calcium carbonate. The oxygen you used up is replaced using the stocked small canisters of pure oxygen to inject fresh oxygen in the air when the breathing cycle is started over again. A rebreather also maintains the oxygen content at the optimum through oxygen sensors included in the breathing set. A negative feedback mechanism controls the rate of oxygen-delivery.
A rebreather has multiple benefits over the other breathing apparatus available on the market, making it an asset in some circumstances. A rebreather offers an improved gas efficiency. While conventional breathing sets waste oxygen since your exhaled air has an oxygen content of 16%, a rebreather recycles the oxygen to be used again. The rebreather is lighter than other breathing apparatus available commercially. This is explained by the fact that a rebreather only carries pure oxygen leaving behind the 78% nitrogen content of atmospheric air.
With a rebreather, you can expect a lot less decompression sickness because nitrogen in the breathing system is kept at a minimum threshold. Divers can afford to stay in the water longer than with the conventional scuba gear. Rebreathers produce few or no bubbles at all and therefore cause minimum disturbance to aquatic life. The diver moves stealthily to catch the underwater life unawares.
Over the years, rebreather diving has killed a fair number of people, some of whom were believed to be competent divers, owing to complications arising when the owners do not get acquainted with their diving gear well enough before venturing out. The number of diving fatalities involving rebreathers is on the rise since 1998 increasing from 1 to 5% in the United States. Common diving disorders when using a rebreather includes deep water blackout caused by hypoxia when the oxygen partial pressure of the re-breathed air gets too low to sustain life, oxygen toxicity caused by a partial pressure of oxygen too high, reaching hyperoxic levels. Disorientation, severe headacheand hyperventilation owing to an excessively high content of carbon dioxidein the recycled air. This is usually caused by a failure in the scrubber system. For these reasons, you will find a rebreather diver training course is even more intensely orientated around safety than a standard commercial diving or scuba diving course.
A rebreather is undoubted a fine piece of technology considered as an indispensable asset in many professional diving fields. There are pros and cons but it’s up to you as a rebreather diver to take your responsibilities and dive safe all the time. A professional rebreather diving course would be a good way to start.
Ben Dixon is an HSE registered Commercial Diver and the owner of Commercial Diving Magazine – an online community for scuba diving and commercial diving fans. If you want to learn about anything from commercial diving to how to become a commercial diver or types of commercial diving jobs you’ll find the information you need and the friends to talk about it with.
Visit Commercial Diving Magazine and join in today!