Nowadays, there are several types of machines. What is a recycler? This system recycles the air, absorbing carbon molecules. There are many models, we can even find sidemount models, but also rebreathers with dorsal or frontal lungs.
On the recycler there are 2 small bottles:
The air thinner (up to 45 m) keeps a minimum volume in the rebreather to be able to breathe comfortably.
A pure oxygen cylinder: this cylinder is the source of O2 for the recycler.
That's why we decided to make a selection for you, to see the advantages and disadvantages of different types of recyclers. There are 2 large categories of recyclers:
The hybrid / electronic rebreather:
It is the modern recycler with a computer that serves primarily as a controller. It allows to control the machine and allows to define a PpO2. A solenoid opens and injects into the rebreather a little oxygen to the desired level.
When looking at recyclers, this is the type of machine that seems most suitable. The comfort of the electronics is pleasant, and the concept at first glance seems the most suitable. We can however say that electronics and water do not mix well, but nowadays, the machines are very well designed we can take as an example the revo, a machine with two canisters. If we apply all the processes, in case of problem, we are able to respond to any type of emergency and in a safe way. Electronics also have the enormous advantage of avoiding the problem of human error.
This remains machines that are still very expensive and therefore not very affordable. In case of breakdown, it is necessary to return the machine to the manufacturer with the transport costs at his expense, not to mention the time lost to be without his equipment and not being able to dive during this lapse of time. There are still some machines like Submatix and Megalodon from ISC or almost all parts can be replaced by the user. The system used in this case is the principle of plug and play, which allows computers to be dismounted. The Solenoid can be replaced, as when changing batteries and all this with great ease.
Of course, these rebreathers can also be used in manual mode during the dive, but as a general rule when a breakdown occurs before a dive, the machines will lock to prevent accidents.
The manual recycler:
This is the origin of the CCR, with a mechanical system. The operation is exactly the same except that there are no batteries and very little electronics (the cells and the PpO2 display remain.). In general, the user must himself inject the oxygen and the diluent. There are also other mechanical systems as on the recyclers Submatix ou KISS a small continuous oxygen leak is regulated there. This adjustment is made according to the oxygen metabolism of each person. The big advantage is that once the flow rate is selected, the PpO2 stabilizes thanks to the depth.
It is still important to monitor your PpO2 and adjust it by injecting oxygen if necessary.
After having dived for a long time with electronic and manual rebreathers, this remains the best option. Besides being the most economical solution, these machines are easy to maintain.
It is the most common trim used by most manufacturers. The canister and electronics are located in the back, 2 bottles are attached to each side of the canister. We can find different kinds of lungs depending on the manufacturer. Some lungs are in the back between the wing and the diver, allowing some freedom of movement. In the past, this type of lung had the disadvantage of making breathing less easy, especially when you rolled over onto your back.
Most manufacturers offer frontal lungs with two lungs: an inspiratory and an expiratory lung. These lungs have the advantage of being comfortable in terms of breathing, but have the disadvantage of taking up space in front, which can be awkward in terms of mobility underwater and more specifically for underwater photography or video. A recent technological advance has made it possible to create hybrid lungs called OTS. (On Top of Shoulder - "on the shoulders".) These lungs combine comfort and freedom of movement.
The first recyclers like Oxygers were designed this way. This type of model has remained the type of system most used by combat swimmers, mechanical and pure O2 (combat swimmers do not descend to very great depths). Two brands manufacture headlamps that can be used for recreational diving. The Triton is a fully manual machine designed in France. Submatix offers a ventral with also the possibility of controlling the rebreather electronically.
These are the very new generations of recyclers. Originally made for cave divers. Sidemount has become a benchmark for many open circuit divers; this trim is very comfortable and has the advantage of being able to adapt the equipment to its morphology, but also to its way of diving. The sidekick from KISS, the ABS from Submatix or the SF2. It should also be noted that these rebreathers are often also taken as emergency rebreathers, particularly practical for cave diving!
This standard is a guarantee of quality, but also the sign that a machine has been developed according to a standard charter established by the European Community. This concerns the type of materials chosen, the diameter of the pipes, the type of regulators used, in short, everything has a standard imposed. To dive in France and Europe legally on a rebreather, it is imperative that the model concerned is the European standard.
Which recycler to choose?
Before deciding, it is important to think carefully about what use you want to have: travel, leisure, photography, deep teak cave diving.
The teks recyclers for deep diving like the JJ-CCR are excellent machines (however its weight remains a major problem). In return for lightweight machines such as ABS or the Pathfinder are limited to 60 m by their manufacturers.
The rebreather is a great tool that offers us new diving perspectives where we can rediscover diving in a totally different way. However, these machines represent a considerable investment, it is therefore advisable to try several before stopping on a specific make or model. It is important to understand their interfaces, because in the end rebreathers have the same operating mode. Each manufacturer has its own way and it is better to use a machine that appears intuitive to the user.
There are also some machines that promise technical feats through technology or electronics. We strongly advise against these machines. Some of them work perfectly, but we end up with a real gas plant, too complex, over-thought, often very heavy (32-45kg). This was already the case with Sentinel or else Liberty, extra machines, but with a lot of gadgets. Other machines have been designed with too much electronics breaking down all the time.
The latest generations of Sidemount rebreathers are relatively light, between 10 and 12 kg ready to dive (without the bottles). Some are indeed limited by depth, but not all of them. So it is really important to be well informed about the capabilities and characteristics of a machine.
Do not hesitate to meet rebreather divers in clubs or forums, to talk with several trainers and to make up your own mind!
After having plunged into CCR for almost ten years, we can say one thing: if you choose a machine prefer simplicity and rather minimalist models.
There is no such thing as a perfect machine, what will really make the difference in the end is not so much the machine. Equally valuable is the quality of the training and the trainer you choose.
Learning to prepare well for diving and being able to solve a problem by itself can make all the difference in case of a glitch.
A training of quality and therefore just as important as the choice of your recycler.
In terms of equipment and recycler, always take time. So enjoy without hurry.
Here we refer some trainers:
Christian Heylen: www.purediving.com
Text: Bam Bam
Credit photo: Jean Louis Rose