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1) What is a semiclosed rebreather?
It is a unit that recycles part of the exhaled breath gas. The oxygen essential for diver's support enters in the circuit by a continuous flow of mixed gas.
2) Diving with a semiclosed rebreather is difficult?
No, it is only different. In other words, you must attend a specific training, exactly as open circuit diving.
3) Only technical divers can use semiclosed rebreather?
No, you can dive with a semiclosed rebreather in all sporting dives without decompression.
4) What kind of advantages has a semiclosed rebreather
 compared with a closed one?
It is easier diving and servicing, specifically for dives within 40 meters.
5) What kind of advantages has a semiclosed rebreather rispetto
an open one?
- Range: It can reach, dependently of the mixture of gases used, until
three hours and more.
- Silence: Without doubt, this is the first advantage the new user notices. The impact of the standard open circuit Scuba in the underwater ambient is rough, and fishes and other marine animals are very troubled and scared by the noise. In the semiclosed rebreather the breath is absolutely quite and the bubbles diffusion very limited in quantity and dimension. Several underwater scientists and photographers are using semiclosed reabreathers for these reasons.
- Trim: The breathing cycle is completely closed inside the lungs, and the diver doesn't notice trim's fluctuations during inspiration and exhalation. The different trim due to the gas consume is very low, usually the diver inflates the B.C. jacket very rarely.
- Heat: After few breaths the heat from the chemical reaction in the filter makes the gas mixture heater then the ambient, and this condition remain during the whole dive. The situation in open circuits is completely different: the gas mixture is initially at ambient temperature, and then colder because the expansion.
- Humidity: The water in breathing and from the chemical reaction maintain the humidity constantly at 100%. The situation in open circuit is different, the gas mixture is completely dry, and the diver loses a big quantity of liquids during the dive.
6) How can I calculate the consume of gas in a semiclosed
rebreather?
It is very easy: you multiply the continuous flow (litres per minute) by the total time of dive (in minute). It is important to remember that the flow (as mass) is constant, independently from the external pressure.
7) Is the Azimuth’s scrubber canister similar to other semiclosed rebreathers?
No, it is quite different. The canister type is a radial flow design: The exhaled gas passes through an inner water -trapping chamber and is forced to flow through the anti - channeling perforated pipe in the middle of the canister. Gas flows through the cross section and radiates outwards through the absorbent. In this way the gas flow can not create preferred ways. In the same time the breathing effort is very low.
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