Respiratory apparatus of the closed cycle ap “alpha. Russian special forces will receive a double-medium breathing apparatus Closed-loop oxygen rebreather

The command of the special operations forces of the Russian Federation received new two-medium breathing apparatus, the so-called rebreathers. Journalists of the newspaper "" write about this. Thanks to the new devices, the Russian military will be able to breathe both when diving to a depth of up to 20 meters, and when skydiving from a height of 8-10 thousand meters above sea level. According to experts, universal breathing devices that could work both under water and in rarefied air existed only in two countries - the USA and Germany (team "seals" No. 6 and the German Kommando Spezialkräfte, respectively). Now Russia will be added to these two states. Thanks to the new double-medium breathing apparatus, the operational and tactical capabilities of the fighters of the Russian Command of Special Operations Forces will increase significantly.

Until recently, all Russian special forces, when performing complex tasks with landing from a great height, had to wear a special breathing apparatus on high altitude and scuba diving. After landing on the water, the commandos changed their masks and switched the supply of breathing mixture before diving. With the advent of the new DA-21Mk2D rebreather, the need to switch the supply of the breathing mixture has disappeared. In addition, thanks to the new breathing apparatus, the composition of the equipment of Russian fighters can be reduced. New double medium Breathe-helping machine was designed jointly by the St. Petersburg State Marine technical university(SPbGMTU) and the Ryazan Higher Airborne Command School (RVVDKU).

The mass of the device DA-21Mk2D is approximately 10 kilograms. It is designed for normal operation at ambient temperatures from -2 to +30 degrees Celsius. The resiber contains enough breathing mixture for continuous operation for four hours. The new double-medium breathing apparatus belongs to the apparatus closed loop. DA-21Mk2D was equipped with a special calcium hydroxide capsule. It is through it that the air exhaled by a special forces soldier passes. Calcium hydroxide is absorbed from exhaled air carbon dioxide with the formation of calcium carbonate. Then the air, purified from carbon dioxide, is enriched with oxygen and again enters the fighter's breathing mask.

Rebreather dummy DA-21Mk2D Source: Oceanos

The first rebreather in the Soviet Union, designed specifically for paratroopers, appeared in the first half of the 1970s. The device received the designation IDA-71P. This device is designed to perform jumps into the water from a small height, at which special forces can do without an oxygen mask. Today, the IDA-71P is in service with reconnaissance divers and combat swimmers. The device belongs to the regenerative type rebreathers; in addition to the usual carbon dioxide absorber, this breathing apparatus also uses a special regenerative substance based on sodium peroxide. This substance not only successfully absorbs carbon dioxide, but also releases oxygen, which is then mixed with the purified air. The implementation of such a scheme allows to reduce the consumption of oxygen from the cylinder.

Tests of the new breathing apparatus DA-21Mk2D should take place in the summer of 2017 in the Crimea. They are planned to be based training center Special Operations Forces (SOF), Izvestia reports, citing representatives of the Russian military who are familiar with the test plans. At present, a new two-media respiratory system is already undergoing underwater tests, which, according to plans, should be completed in late 2016 - early 2017. After that, the system will be tested at an altitude of 10,000 meters. Directly in the Crimea, the command of the special operations forces will be engaged in a comprehensive check of the apparatus, with the performance of long parachute jumps into the water.

According to Alexei Blinkov, head of the Department of Defense Research and Development, the unique dual-medium breathing system was developed on the basis of the DA-21Mk2 complex, which is already in service with the Russian fleet. AT new version the device, which received the prefix "D" ("landed"), was significantly improved. So, according to the requirements of the military, the mount of the apparatus was transferred to the chest. This is done so that the paratrooper can carry a two-medium breathing apparatus along with a parachute pack. Also, the device was significantly lightened, its weight decreased by more than two times - from 21 to 10 kilograms due to the use of modern composite materials and refusal to supply a nitrogen-oxygen mixture in favor of ordinary oxygen. According to Aleksey Blinkov, special forces perform tasks under water at a depth of up to 20 meters. In this regard, after consulting with the military, we have decided to refuse the use of a nitrogen-oxygen mixture, which is not intended for breathing at high altitude.

Under normal conditions, combat swimmers are delivered to the site of sabotage on submarines and ships, - says military expert Vladislav Shurygin. - However, in the presence of hydroacoustic barriers, modern coastal defense radar stations and patrols, penetrate into the desired area traditional way underwater saboteurs do not always succeed. It is for this reason that today a system has developed in the world when special forces soldiers make long high-altitude jumps with a landing in the water, and only then they begin to solve the tasks assigned to them, including going ashore.

It must be remembered that the equipment that combat swimmers use today is seriously different from the usual for all people familiar with diving, cylinders with compressed air and oxygen. Such containers would take up a lot of space on the human body. In addition, they have a rather unpleasant factor - the air that is exhaled from the lungs enters the water through the valves in the form of bubbles that unmask the swimmer. At the same time, closed-cycle devices (rebreathers) are much more compact, and their operation is based on a different principle - oxygen is not stored in separate container, it is generated using chemical reaction. At the moment of exhalation, the air from the swimmer's lungs, in which the carbon dioxide content is increased, and the oxygen content, on the contrary, is lowered, is sent to a special container, in which there is a regenerating element that absorbs carbon dioxide. Subsequently, the oxygen-enriched mixture again enters the inhalation channel. The device is able to provide the ability to breathe underwater for several hours, and this time period is calculated taking into account the fact that the commando will actively move, while consuming much more oxygen.

In addition to compactness, all rebreathers have another important advantage: closed-cycle devices almost do not release bubbles into the water. Of course, some of the swimmer's exhalation is vented through a special valve, but these are so small volumes that there are no air bubbles on the surface of the water that could unmask the special forces soldier and disrupt the combat mission.

Information sources:
http://izvestia.ru/news/639512
https://nplus1.ru/news/2016/10/24/rebreather
http://www.utro.ru/articles/2016/10/25/1302166.shtml

Encyclopedic YouTube

1 / 5

✪ We blow up RP-4 | Making a big boom

✪ Donetsk plant of mine-rescue equipment

✪ disassembly of the R-30, R-34 respirator

✪ Deutscher Sauerstoff Selbtretter SAR 30 review (ger.)

✪ Intelligence questioning: Yuri Bychkov about the work of a firefighter

Subtitles

Closed loop rebreathers

Closed Oxygen Rebreather - O2-CCR

This is the ancestor of rebreathers in general. The first such apparatus was created and used by the British inventor Henry Fluss in the middle of the 19th century while working in a flooded mine. The closed circuit oxygen rebreather has all the main parts that are typical for any type of rebreather: breathing bag, chemical absorber canister, breathing hoses with valve box, bypass valve (manual or automatic), evacuation valve and cylinder with reducer high pressure. The principle of operation is as follows: oxygen from the breathing bag enters the diver's lungs through a non-return valve, from there, through another non-return valve, oxygen and carbon dioxide formed during breathing enter the chemical absorber canister, where carbon dioxide binds with caustic soda, and the remaining oxygen returns to the breathing bag. Oxygen, replacing that consumed by the diver, is supplied to the breathing bag through a calibrated nozzle at a rate of approximately 1 - 1.5 liters per minute, or is added by the diver using manual valve. When diving, the compression of the counterlung is compensated either by actuation of an automatic bypass valve or by a manual valve controlled by the diver himself. It should be noted that, despite the name "closed", any closed circuit rebreather releases bubbles of breathing gas through the evacuation valve during ascent. To get rid of bubbles, caps made of fine mesh or foam rubber are installed on the etching valves. This simple device is very effective and reduces the bubble diameter to 0.5 mm. Such bubbles completely dissolve in water already after half a meter and do not unmask the diver on the surface.

The limitations inherent in closed-cycle oxygen rebreathers are primarily due to the fact that these devices use pure oxygen, the partial pressure of which is the limiting factor in diving depth. So, in sports (recreational and technical) training systems, this limit is 1.6 ata, which limits the depth of immersion to 6 meters in warm water with minimal physical exertion. In the Navy of the FRG, this limit is 8 meters, and in the Navy of the USSR - 22 meters.

Closed circuit rebreather with manual oxygen supply - mCCR or KISS

This system is also called K.I.S.S. (Keep It Simple Stupid) and invented by Canadian Gordon Smith. This is a closed-cycle rebreather with the preparation of the mixture "on the fly" (selfmixer), but in the maximum simple execution. The principle of operation of the device is that 2 gases are used. The first, called the diluent, is automatically or manually fed into the breathing bag of the apparatus through the lung governed demand valve or bypass valve, respectively, to compensate for the compression of the breathing bag during immersion. The second gas (oxygen) is supplied to the breathing bag through a calibrated orifice at a constant rate, however, less than the rate of oxygen consumption by the diver (about 0.8-1.0 liters per minute). When diving, the diver must himself control the partial pressure of oxygen in the breathing bag according to the readings of electrolytic sensors of the partial pressure of oxygen and add the missing oxygen using a manual supply valve. In practice, it looks like this: before diving, the diver adds some amount of oxygen to the breathing bag, setting the required partial pressure of oxygen using the sensors (within 0.4-0.7 atm). During a dive, diluent gas is automatically or manually added to the breathing bag to compensate for depth, reducing the oxygen concentration in the bag, but the oxygen partial pressure still remains relatively stable due to the increase in water column pressure. Having reached the planned depth, the diver, using a manual valve, sets any partial oxygen pressure (usually 1.3) works on the ground, monitoring the readings of oxygen partial pressure sensors every 10-15 minutes and adding oxygen if necessary to maintain the required partial pressure. Usually, in 10-15 minutes, the partial pressure of oxygen decreases by 0.2-0.5 atm, depending on physical activity.

Not only air, but also trimix or heliox can be used as a diluent gas, which allows diving with such an apparatus to very decent depths, however, the relative variability of the partial pressure of oxygen in the breathing circuit makes it difficult to accurately calculate decompression. Usually with devices that have only an indication of the partial pressure of oxygen in the circuit, they dive no deeper than 40 meters. If a computer is connected to the circuit that can monitor the partial pressure of oxygen in the circuit and calculate decompression on the fly, then the depth of the dive can be increased. The deepest dive with a device of this type can be considered the dive of Matthias Pfizer, who dived in Hurghada to 160 (one hundred and sixty) meters. In addition to oxygen partial pressure sensors, Matthias also used a VR-3 computer with an oxygen sensor that monitored the partial pressure of oxygen in the mixture and calculated decompression taking into account all changes in the breathing gas.

Exist a large number of conversions of commercial, military and sports rebreathers under the K.I.S.S. system, but all this, of course, unofficially and under the personal responsibility of the diver who converted and uses them.

Electronically Controlled Closed Circuit Rebreather - eCCR

Actually, a real closed-loop rebreather (electronically controlled selfmixer). The first such apparatus in history was invented by Walter Stark and was called the Electrolung. The principle of operation is that the diluent gas (air or trimix or heliox) is supplied by a manual or automatic bypass valve to compensate for the compression of the breathing bag during diving, and oxygen is supplied by a microprocessor-controlled solenoid valve. The microprocessor interrogates 3 oxygen sensors, compares their readings and averaging the two closest ones, sends a signal to the solenoid valve. The readings of the third sensor, which differ the most from the other two, are ignored. Typically, the solenoid valve operates every 3-6 seconds, depending on the diver's oxygen consumption.

The dive looks something like this: the diver enters into the microprocessor two values ​​of the partial pressure of oxygen, which the electronics will maintain during different stages of the dive. Usually it is 0.7 ata for exit from the surface to the working depth and 1.3 ata for being at depth, passing through decompression and ascent up to 3 meters. Switching is carried out by a toggle switch on the console of the rebreather. During the dive, the diver must monitor the operation of the microprocessor to identify possible problems with electronics and sensors.

Structurally, electronically controlled closed-cycle rebreathers have practically no depth restrictions, and the actual depth at which they can be used is mainly due to the error of oxygen sensors and the strength of the microprocessor housing. Usually the maximum depth is 150-200 meters. Electronic closed circuit rebreathers have no other restrictions. The main disadvantage of these rebreathers, which significantly limits their distribution, is high price the device itself and Supplies. It is important to remember that conventional computers and decompression tables are not suitable for diving with electronic rebreathers, since the partial pressure of oxygen remains constant throughout most of the dive. With this type of rebreather, either special computers (VR-3, VRX, Shearwater Predator, DiveRite NitekX, HS Explorer) must be used, or the dive must be pre-calculated using programs such as Z-Plan or V-Planer for the lowest possible oxygen partial pressure (at the same time, it is necessary to strictly monitor that the value of the partial pressure does not decrease below the calculated one, otherwise the risk of getting DCS increases many times). Both programs are recommended for use by manufacturers and builders of all electronic rebreathers.

Semi-closed circuit rebreathers

Active feed semi-closed circuit rebreather - aSCR

This is the most common type of rebreather used in sport diving. The principle of its operation is that the breathing mixture EANx Nitrox is fed into the breathing bag at a constant speed through a calibrated nozzle. The feed rate depends only on the concentration of oxygen in the mixture, but does not depend on the depth of immersion and physical activity. Thus, the oxygen concentration in the breathing circuit remains constant during constant exercise. Obviously, with this method of supplying breathing gas, its excess occurs, which are removed into the water through the evacuation valve. As a result, a semi-closed cycle rebreather releases several bubbles of the respiratory mixture not only during the ascent, but also with each exhalation of the diver. About 1/5 of the exhaled gas is vented. To increase stealth, caps-deflectors, similar to those used in closed-cycle oxygen rebreathers, can be installed on the etching valves.

Depending on the oxygen concentration in the EANx (Nitrox) breathing mixture, the flow rate can vary from 7 to 17 liters per minute, so the time spent at depth when using a semi-closed circuit rebreather depends on the volume of the breathing gas cylinder. The depth of immersion is limited by the partial pressure of oxygen in the breathing bag (should not exceed 1.6 atm) and the set pressure of the reducer. The fact is that the outflow of gas through a calibrated orifice has a supersonic speed, which allows you to keep the flow unchanged as long as the set pressure of the reducer exceeds the ambient pressure by two or more times.

Semi-closed-loop rebreather with passive feed - pSCR

The principle of operation of the device is that part of the exhaled gas is forcibly vented into the water (usually 1/7 to 1/5 of the volume of inhalation), and the volume of the breathing bag is obviously less than the volume of the lungs of the diver. Due to this, for each breath, a fresh portion of the respiratory gas is supplied through the lung machine into the breathing circuit. This principle allows you to use any gases other than air as a breathing mixture and very accurately maintain the partial pressure of oxygen in the breathing circuit, regardless of physical activity and depth. Since the supply of breathing gas is carried out only on inspiration, and not constantly, as is the case with rebreathers with active feed, then the semi-closed cycle rebreather with passive feed limited in depth only by the partial pressure of oxygen in the breathing circuit. A significant negative point in the design of semi-closed cycle rebreathers with passive supply is that the automation is activated by the diver's respiratory movements, which means that the severity of breathing is obviously greater than on other types of apparatus. Devices using a similar principle of operation are preferred by underwater speleologists and followers of the DIR teaching in diving.

Mechanical Self Mixer - mSCR

A very rare design of a semi-closed cycle rebreather. The first such apparatus was created and tested by Drägerwerk in 1914. The principle of operation is as follows: there are 2 gases (oxygen and diluent) that are supplied through calibrated nozzles into the breathing bag, as in a semi-closed circuit rebreather with an active supply. Moreover, the supply of oxygen is carried out at a constant volumetric velocity, as in closed rebreather with manual feed, and the diluent enters through the nozzle with a subsonic flow velocity, and the amount of supplied diluent increases with increasing depth. Compensation for compression of the breathing bag is carried out by supplying diluent through an automatic bypass valve, and excess breathing mixture is bled into the water in the same way as in the case of a semi-closed cycle rebreather with active supply. Thus, only due to a change in water pressure during the dive, the parameters of the breathing mixture change, and in the direction of a decrease in the oxygen concentration with increasing depth. Mechanical selfmixers tend to change the oxygen concentration in the breathing bag with changes in physical activity, and this is a direct consequence of the fact that their principle of operation is very similar to the principle on which semi-closed rebreathers with active supply are built.

Depth limits for a mechanical selfmixer are the same as for a semi-closed circuit rebreather with active supply, with the exception that only the set pressure of the oxygen reducer must be 2 or more times the ambient pressure. In terms of time, the selfmixer is mainly limited by the volume of diluent gas, the flow rate of which increases with depth. Air, Trimix and HeliOx can be used as diluent gas.

Semi-closed circuit rebreather with active feed with mixture preparation in the feed process

A very rare design of a semi-closed cycle rebreather. This type of rebreather, by its principle of operation, is completely similar to a semi-closed cycle rebreather with active supply, except that the breathing mixture is prepared not in advance, but during the operation of the rebreather. The principle of operation is as follows: there are 2 gases (oxygen and diluent) that are supplied through calibrated nozzles into the counterlung, just like in a semi-closed circuit rebreather with an active supply. Both oxygen and diluent are delivered at a constant rate regardless of depth, with the gases mixing in the counterlung. Depending on the rate of oxygen and diluent supply, we get the gas we need. This type of rebreather has all the disadvantages of a semi-closed rebreather with an active supply, in addition, it is structurally more complex and requires at least two gas cylinders (while only one gas cylinder is needed for normal operation of an aSCR). The advantage of this type of rebreathers is that there is no need to prepare the breathing mixture in advance and it is possible to set the desired gas in the circuit (by adjusting the O2 and diluent supply rates) without changing the source gases, but only their proportion. The following diluent gases can be used: air, Trimix and HeliOx.

Regenerative rebreathers

Regenerative rebreathers can operate in both closed and semi-closed breathing patterns. Their main difference is that, in addition to (instead of) the usual carbon dioxide absorber, a regenerative substance is used: O3 (o-tri), ERW or OKCh-3, created on the basis of sodium peroxide. The regenerative substance is capable of not only absorbing carbon dioxide, but also releasing oxygen. The principle of operation of a regenerative rebreather is that the diver's oxygen consumption is compensated not only by the supply of fresh breathing mixture from the cylinder, but also by the release of oxygen by the regenerative substance.

The classic representatives of regenerative rebreathers are the IDA-59, IDA-71, IDA-72, IDA-75, IDA-85 devices.

Separately, as the most successful design, one can note devices of the IDA-71 type, which are still used in units of combat swimmers and reconnaissance divers. The design of the device and the principle of its operation are simple and affordable. When used correctly, it is very reliable. Despite its “venerable” age (in principle, the device is considered obsolete), it is considered the most successful design devices of this type are still being produced (the Respirator plant). The IDA-75 and IDA-85 devices were produced in an experimental series, but due to the collapse of the USSR, they did not go into the series. After the collapse of the USSR, design bureaus have not yet invented an apparatus superior in its characteristics to the IDA-71.

Decompression modes are not used during descents in closed-cycle apparatus on pure oxygen. According to the Navy Diving Service Rules, pure oxygen dives are allowed to depths of up to 20 meters. When using mixtures of the AKS and AAKS types, no-decompression descents are allowed to depths of up to 40 meters - in the IDA-71 apparatus, and up to 60 meters in the IDA-75 and IDA-85 apparatuses. The maximum allowable no-decompression time at these depths is 30 minutes. If the specified stay time is exceeded, the exit is carried out in compliance with the decompression mode.

In a closed circuit breathing machine

I must confess that Jude Vandevere's pessimistic remarks, here on board the Orschilla, a few miles from Hopkins station, were like a cold shower.

Still, it's better than giving up. Not always the struggle is crowned with defeat.

The ecological battle is a difficult one: you lose a thousand times, you start over a thousand times, but for the sake of future generations, we must fight it without losing. We must do this for ourselves.

Jude Vandever agrees with this completely. Most of his life was spent in search of means to save the last sea otters, and you can’t blame him for defeatism in any way ... Simply, a scientist cannot rely only on his feelings: realists must face the truth.

I wonder what he wants to tell me, right now, while I explain all this, the sea otter, which looks at me from the algae about two meters from us ...

Calypso divers, who were already at the ready, descend into the water. Instantaneous reaction: sea otters, who were quite good-natured just a second ago, scatter in different sides. Indeed, until now the diver was their sworn enemy - he came with his underwater gun to exterminate them. This is the first time sea otters deal with unarmed visitors - but their right to distrust a person is quite legal.

Up to a certain point, however. There is one more circumstance.

It took us a while to realize that the sight and noise of the air bubbles from our scuba tanks attracted them and repelled them at the same time. If we really want to get close to sea otters in their environment, we need to find some other, more relaxed way to do this.

As swimmers come to the surface with empty abalone shells - sea otters discarded them after tearing clams from underwater rocks and eating their flesh - I tell myself that there are only two ways to approach sea otters, to play hide and seek among seaweed with these shy clowns - either an apparatus with a closed breathing cycle or nothing.

The closed-loop oxygen machine, whose main advantage is the absence of air bubbles and complete silence, was created by the military for their own needs. Thanks to him, submariners do not give themselves away with their breath and become indistinguishable from the surface.

We used this cunning system when dealing with wild animals, which were horrified by the garlands of silver bubbles and the breathing noise of swimmers in ordinary spacesuits.

But I do not hide the fact that I do not gain anything from this. Although Calypso swimmers have extensive experience with all kinds of submersibles, I don't like it when they use oxygen apparatus. The oxygen apparatus causes numerous troubles even for well-trained swimmers. With such a device, any mistake can be fatal.

The essence of the device lies in the fact that it is supplied with a granular substance that regenerates the air exhaled by the swimmer into the breathing bag. If nothing comes out of the system, then you should carefully ensure that not a single drop of water penetrates there: the effectiveness of the cleaning tank will be impaired, and this is fraught with serious and painful burns to the oral cavity for a person.

Kalaniha bit Philippe Cousteau because she likes him.

But the main danger lies in the use of pure oxygen. This gas, when it enters the blood in large quantities - which occurs when the pressure of the water increases according to the depth of immersion - causes serious organic disorders. It acts on nervous system, causing the famous "deep drunkenness", which leads to convulsions and coma - and in the latter case to a sad end.

Swimmers and sea otters in Stillwater Bay.

The depth at which the first signs of “oxygen intoxication” are felt averages only 7 meters: a serious limitation ...