Getting to know Rebreathers

October 2007

Author: George Petrou Instructor Trainer TDI, SDI. PADI MSDT, CMAS / EODAATK 3***. Photos: George Petrou / Nasos Zervopoulos

OCTOBER 2007

Rebreathers have a long and important history of contribution throughout the history of diving. The recycling of the mixture is the basic idea and is implemented with this breathing machine. Today more than ever, Rebreathers are used by technical diving enthusiasts as the properties they have offer great advantages in deep diving, cave diving where great penetration is required, etc.

In this article we briefly know their basic anatomy.

Getting to know Rebreathers

October 2007 and we have traveled to Tergieste, Italy, to Nicola Donda's HBT (Human Body Technology) Rebreather manufacturing plant. There, in addition to purchasing a rebreather, we would take a seminar and delve into the secrets of these magical diving machines that support a person's life underwater.

Let's not forget that we are under mechanical respiratory support underwater.

We will see together the parts that make up a Rebreather (R) as we assemble it together step by step or better piece by piece.

We begin with the image of a modern, new generation Rebreather (R), semi-closed circuit which can be converted to closed circuit.

But let's disassemble our R to look at it from the beginning.

· Κατ' αρχήν πλένουμε καλά την θήκη (Housing) το οποίο θα δεχθεί το δοχείο με τον Νατράσβεστο. Η άριστη στεγανοποίηση αυτού της θήκης είναι απαραίτητη προϋπόθεση ασφάλειας.

Contrary to those who believe that there should be no moisture at all in the filtering material, I tell you that moisture is necessary to activate the filtering process. The initial moisture comes from our exhalation!!!

· We take our transparent container and place the stainless steel mesh (photo 1180), the white separating filter and the guide for inserting the filtering material.

· We pour the filtering material by blowing to remove the dust), we hit-shake the container to make the material more compact, the material should reach a certain point in the container, then the stainless steel mesh & separating filter is put back in. We secure it with a stainless steel butterfly and put on the special lid.

· Place the spring at the base of the container and on top of this container with the soda lime.

· "Μετράμε" την τάση του αισθητήρα και συνδέουμε αυτόν .

· Κλείνουμε το καπάκι του δοχείου με τον αισθητήρα που έρχεται σε επικοινωνία με τους αναπνευστικούς σάκους - breathing loop.

· Clip the breathing bags to the buoyancy regulator and screw on the breathing tubes.

· The breathing tubes and the mouthpiece are checked for tightness very carefully before installation.

· Connect the breathing tubes to the mouthpiece, pay attention to the non-return valve for the mixture inlet and outlet.

· We connect the pressure regulator to our bottle, the container with the filter/sensor and the mass flow.

· Be careful of the non-return valve that may allow water to enter the filtration tank system.

· The correct connection of the mass flow is a necessary safety requirement. The mass flow system essentially supplements our requirement for additional mixture when we need it. The blue switch allows us to change to the spare bottle.

· We check the correct connection and operation of the PPO2 digital manometer.

· We place our bottles, adjust the flow in liters.

· Pay attention to the Second Stage at the top, which assists when the diver wants a higher flow rate, and the mixture exhaust valve on the breathing bag, here the system becomes semi-closed.

· And it's time to put on the R and do our necessary checks. With the R you have to be meticulous in detail.

· Για το φινάλε σας άφησα την σειρά δοκιμών για το αναπνευστικό σύστημα με το R. . Έντονο τρέξιμο στο ποδήλατο και έλεγχος πνευμόνων, CO2 & PPO2.

This was of course a very brief introduction to R and in no case can the knowledge that someone can get from one article be sufficient. Undoubtedly, R are excellent in their benefits but also very demanding from the user. As we said in a previous issue, Rebreathers or rebreathers have a long and important history in the history of diving. The idea of recycling the mixture is a basic idea and is implemented with this breathing machine. However, most people have not seen and know little about it.

This was of course a very brief introduction to R and in no way can the knowledge that one can gain from one article be sufficient.