REBREATHER PZ-2
In public design office of institute of a name of the academician Krilova a series of respiratory devices of the half-closed cycle is created. During two years one of updatings such device PZ-2, created is used on the basis of standard scuba AVM-3. At creation of the device for a basis the West-German device FGG-III was taken which was complemented by the emergency respiratory automatic device (“Ukraina-2”).
The device is intended for performance of easy physical works on depths up to 10m and any works on depths 10 — 40 m (at use of air). Thus the operating time in it(him) makes from 90 up to 60 min. (fig. 1), that is on depth 40 m in 4 — 5 times more, than in standard scuba.
Partal pressure of oxygen submitted by the device PZ-2 on a breath to the diver, with depth changes, this change can be expressed by the table.
Percentage and partal pressure of oxygen
At use of air (21 % O2)
| Depth of immersing | Constant submission (l/min). | Easy work (0.8 l/min). |
Average work (1.7 l/min). |
Heavy work (2.5 l/min). |
| 0 | 20 | 17.7% / 0.177 | 13.6% / 0.136 | |
| 5 | 21.5 | 17.9% / 0.268 | 14% / 0.210 | 10.5% / 0.157 |
| 10 | 22.5 | 18% / 0.360 | 14.5% / 0.290 | 11.1% / 0.222 |
| 15 | 23.75 | 18.2% / 0.455 | 14.8% / 0.370 | 11.6% / 0.290 |
| 20 | 25 | 18.3% / 0.549 | 15.2% / 0.456 | 12.2% / 0.366 |
| 25 | 26.25 | 18.5% / 0.647 | 15.5% / 0.542 | 12.6% / 0.441 |
| 30 | 27.5 | 18.6% / 0.744 | 15.7% / 0.628 | 13% / 0.520 |
| 35 | 28.75 | 18.7% / 0.841 | 16% / 0.720 | 13.4% / 0.603 |
| 40 | 30 | 18.8% / 0.940 | 16.2% / 0.810 | 13.8% / 0.690 |
| 45 | 31.25 | 18.9% / 1.039 | 16.4% / 0.902 | 14.1% / 0.775 |
Fig. 1. The diagrams of dependence of the charge of air and duration of work in the device PZ-2 and scuba from depth of immersing
The general view of the device PZ-2 is shown on a photo.
Characteristics of the device:
Depth of immersing — 40 m (at use of air); weight — 25 kgs; a stock of air — 1500 L; a stock of an absorber HP-I — 1,8 kgs; adjusting pressure of a reducer (in a static) — 6 bar;
Weight in water — + 1 kg; resistance to breath at constant ventilation 30 l/min — 55 mm. of a water pole.
The device PZ-2 is simple on the device, in it(him) the details of standard respiratory devices are used:
AVM-3 — Panel with belts, cylinders, goffered hoses, reducer adjusted on pressure 5 bar;
“Ukraina-2” — Octopus the automatic device (as reserve);
The regular automatic device with AVM-3 is removed. On his(its) place the block consisting of the case with two opening covers is established in which two respiratory bags and box with a chemical absorber of carbonic gas (HP-I) are placed. The respiratory bags incorporate with each other through a box with HP-I, and also through goffered hoses and mouthpiece. The device works as follows (fig. 2). At opening the gate of the basic submission air (or gas mix) through a washer in quantity(amount) ~ 20 l/min (under normal conditions) move in system, whence is etched in that quantity(amount) periodically (in time Exhalation). The breath is made from a bag of a breath 1, exhalation — In a bag of an exhalation 3. The circulation is provided with valves placed in a mouthpiece 2. The part of exhaled air (gas) is etched, as it was specified above, through the target valve from a bag of an exhalation. The basic flow of air, leaving through a box with a chemical absorber of carbonic gas 4, acts in a bag of a breath, where mixs up with air acting from a cylinder 5 through reducers 6. As the charge of air in scuba changes from 30 l/min on a surface up to 150 l/min on depth 40 m, and in the device of the half-closed cycle varies unsignificantly (from 20 up to 27 — 32 l/min, depending on adjusting pressure of a reducer), it becomes clear, that the system effectiveness grows with increase of depth of immersing.
How it is visible from the table above mentioned, partal the pressure of oxygen is within the limits of norm at performance of easy physical work on depth up to 10 m (???) and any work — From 10 up to 40m (it is!).
Fig. 2. The circuit of work of the device PZ-2
It is necessary also to note, that at use of the device PZ-2 the opportunity of an oxygen poisoning of the diver is excluded, and duly change of a box with HP-I (after each immersing, though the box provides work during 90 — 120 mines) guarantees absence in air of carbonic gas. This is promoted also by removal(distance) of a part sated CO2 of air.
Thus, at correct operation and rigid control of time of stay on depth (for maintenance of possible(probable) stops for decompression) the device of a similar type can be used at work on average (10 — 40 m) depths. His(its) opportunities considerably extend at application of gas mixes.
A. Abaev, engineer
Copy from a magazine “Sportsmen-Podvodnik” of 85
