Depth of human immersion. Deep diving: definition and limits Immersion depth m

When the opportunity to dive to depth arose, the desire to become the best in this matter also appeared. There is a constant struggle for records, despite the negative impact that depth has on a person. For example, water pressure causes ear pain and there is a risk that the eardrum will burst.

Although professional divers cope with this problem easily. The main thing is to equalize the pressure using swallowing movements. In addition, with each meter of depth, water pressure increases, and the volume of air in the lungs decreases.

Because of this, swimmers often incorrectly estimate oxygen reserves, which can subsequently play a cruel joke on the diver. And rising from the depths has its own specifics and difficulties. But despite this, the battle for records continues.

Maximum depth of human immersion

The first dive to a depth of one hundred meters was not even included in sports records. But all divers know the names of the divers who did it. These are Enzo Mallorca and Jacques Mayol. By the way, they became the prototypes of the main characters of the famous film by Luc Besson “Abyss Blue”.

The 100-meter mark has long ceased to be a record. Waugh was accomplished by the Austrian swimmer Herbert Nietzsch. His record in 2001 was 214 meters. By the way, Nietzsche is called a freediving legend.

Throughout his life, he set world records in this type of diving 31 times. Among women, the record holder was American Tanya Streeter. In 2002, it sank to a depth of 160m.

Breathe deeply: a man descends to a depth inaccessible to nuclear submarines.

Roman Fishman

We live on a planet of water, but we know the Earth's oceans less well than some cosmic bodies. More than half of the surface of Mars has been mapped with a resolution of about 20 m - and only 10-15% of the ocean floor has been studied with a resolution of at least 100 m. 12 people have been on the Moon, three have been to the bottom of the Mariana Trench, and all of them did not dare to stick their nose out of the heavy-duty bathyscaphes.

Let's dive in

The main difficulty in the development of the World Ocean is pressure: for every 10 m of depth it increases by another atmosphere. When the count reaches thousands of meters and hundreds of atmospheres, everything changes. Liquids flow differently, gases behave unusually... Devices capable of withstanding these conditions remain piecemeal products, and even the most modern submarines are not designed for such pressure. The maximum diving depth of the latest Project 955 Borei nuclear submarines is only 480 m.

Divers descending hundreds of meters are respectfully called aquanauts, comparing them with space explorers. But the abyss of the seas is in its own way more dangerous than the vacuum of space. If something happens, the crew working on the ISS will be able to transfer to the docked ship and in a few hours will be on the surface of the Earth. This route is closed to divers: it may take weeks to evacuate from the depths. And this period cannot be shortened under any circumstances.

However, there is an alternative route to depth. Instead of creating ever more durable hulls, you can send there... living divers. The record of pressure endured by testers in the laboratory is almost double the capabilities of submarines. There is nothing incredible here: the cells of all living organisms are filled with the same water, which freely transmits pressure in all directions.

The cells do not resist the water column, like the solid hulls of submarines; they compensate for external pressure with internal ones. It’s no wonder that the inhabitants of “black smokers,” including roundworms and shrimp, thrive at many kilometers deep in the ocean floor. Some types of bacteria can withstand even thousands of atmospheres quite well. Man is no exception here - the only difference is that he needs air.

Beneath the surface

Oxygen Breathing tubes made of reeds were known to the Mohicans of Fenimore Cooper. Today, hollow plant stems have been replaced by plastic tubes, “anatomically shaped” and with comfortable mouthpieces. However, this did not make them more effective: the laws of physics and biology interfere.

Already at a meter depth, the pressure on the chest rises to 1.1 atm - 0.1 atm of water column is added to the air itself. Breathing here requires a noticeable effort of the intercostal muscles, and only trained athletes can cope with this. At the same time, even their strength will not last long and at a maximum of 4-5 m depth, and beginners have difficulty breathing even at half a meter. In addition, the longer the tube, the more air it contains. The “working” tidal volume of the lungs is on average 500 ml, and after each exhalation, part of the exhaust air remains in the tube. Each breath brings less oxygen and more carbon dioxide.

Forced ventilation is required to deliver fresh air. By pumping gas under increased pressure, you can ease the work of the chest muscles. This approach has been used for more than a century. Hand pumps have been known to divers since the 17th century, and in the middle of the 19th century, English builders who erected underwater foundations for bridge supports already worked for a long time in an atmosphere of compressed air. For the work, thick-walled, open-bottom underwater chambers were used, in which high pressure was maintained. That is, caissons.

Deeper than 10 m

Nitrogen No problems arose during work in the caissons themselves. But upon returning to the surface, construction workers often developed symptoms that French physiologists Paul and Vattel described in 1854 as On ne paie qu'en sortant - "payback at the exit." It could be severe itching of the skin or dizziness, pain in the joints and muscles. In the most severe cases, paralysis developed, loss of consciousness occurred, and then death.

To go to the depths without any difficulties associated with extreme pressure, you can use heavy-duty spacesuits. These are extremely complex systems that can withstand immersion of hundreds of meters and maintain a comfortable pressure of 1 atm inside. True, they are very expensive: for example, the price of a recently introduced spacesuit from the Canadian company Nuytco Research Ltd. EXOSUIT is about a million dollars.

The problem is that the amount of gas dissolved in a liquid directly depends on the pressure above it. This also applies to air, which contains about 21% oxygen and 78% nitrogen (other gases - carbon dioxide, neon, helium, methane, hydrogen, etc. - can be neglected: their content does not exceed 1%). If oxygen is quickly absorbed, then nitrogen simply saturates the blood and other tissues: with an increase in pressure by 1 atm, an additional 1 liter of nitrogen dissolves in the body.

With a rapid decrease in pressure, excess gas begins to be released rapidly, sometimes foaming, like an opened bottle of champagne. The resulting bubbles can physically deform tissues, block blood vessels and deprive them of blood supply, leading to a wide variety of and often severe symptoms. Fortunately, physiologists figured out this mechanism quite quickly, and already in the 1890s, decompression sickness could be prevented by using a gradual and careful decrease in pressure to normal - so that nitrogen leaves the body gradually, and blood and other fluids do not “boil” .

At the beginning of the twentieth century, English researcher John Haldane compiled detailed tables with recommendations on the optimal modes of descent and ascent, compression and decompression. Through experiments with animals and then with people - including himself and his loved ones - Haldane found that the maximum safe depth without requiring decompression was about 10 m, and even less for a long dive. Returning from the depths should be done gradually and slowly to give the nitrogen time to be released, but it is better to descend rather quickly, reducing the time for excess gas to enter the body tissues. New limits of depth were revealed to people.

Deeper than 40 m

Helium The fight against depth is like an arms race. Having found a way to overcome the next obstacle, people took a few more steps - and met a new obstacle. So, after decompression sickness, a scourge appeared, which divers almost lovingly call “nitrogen squirrel”. The fact is that under hyperbaric conditions this inert gas begins to act no worse than strong alcohol. In the 1940s, the intoxicating effect of nitrogen was studied by another John Haldane, the son of “the one.” His father’s dangerous experiments did not bother him at all, and he continued harsh experiments on himself and his colleagues. “One of our subjects suffered a lung rupture,” the scientist wrote in the journal, “but he is now recovering.”

Despite all the research, the mechanism of nitrogen intoxication has not been established in detail - however, the same can be said about the effect of ordinary alcohol. Both disrupt normal signal transmission at the synapses of nerve cells, and perhaps even change the permeability of cell membranes, turning ion exchange processes on the surfaces of neurons into complete chaos. Outwardly, both manifest themselves in similar ways. A diver who “caught a nitrogen squirrel” loses control of himself. He may panic and cut the hoses, or, conversely, get carried away by telling jokes to a school of cheerful sharks.

Other inert gases also have a narcotic effect, and the heavier their molecules, the less pressure is required for this effect to manifest itself. For example, xenon anesthetizes under normal conditions, but lighter argon only anesthetizes under several atmospheres. However, these manifestations are deeply individual, and some people, when diving, feel nitrogen intoxication much earlier than others.

You can get rid of the anesthetic effect of nitrogen by reducing its intake into the body. This is how nitrox breathing mixtures work, containing an increased (sometimes up to 36%) proportion of oxygen and, accordingly, a reduced amount of nitrogen. It would be even more tempting to switch to pure oxygen. After all, this would make it possible to quadruple the volume of breathing cylinders or quadruple the time of working with them. However, oxygen is an active element, and with prolonged inhalation it is toxic, especially under pressure.

Pure oxygen causes intoxication and euphoria, and leads to membrane damage in the cells of the respiratory tract. At the same time, the lack of free (reduced) hemoglobin makes it difficult to remove carbon dioxide, leads to hypercapnia and metabolic acidosis, triggering physiological reactions of hypoxia. A person suffocates, despite the fact that his body has enough oxygen. As the same Haldane Jr. established, even at a pressure of 7 atm, you can breathe pure oxygen for no longer than a few minutes, after which breathing disorders, convulsions begin - everything that in diving slang is called the short word “blackout”.

Liquid breathing

The still semi-fantastic approach to conquering depth is to use substances that can take over the delivery of gases instead of air - for example, the blood plasma substitute perftoran. In theory, the lungs can be filled with this bluish liquid and, saturating it with oxygen, pump it through pumps, providing breathing without any gas mixture at all. However, this method remains deeply experimental; many experts consider it a dead end, and, for example, in the USA the use of perftoran is officially prohibited.

Therefore, the partial pressure of oxygen when breathing at depth is maintained even lower than usual, and nitrogen is replaced with a safe and non-euphoric gas. Light hydrogen would be better suited than others, if not for its explosiveness when mixed with oxygen. As a result, hydrogen is rarely used, and the second lightest gas, helium, has become a common substitute for nitrogen in the mixture. On its basis, oxygen-helium or oxygen-helium-nitrogen breathing mixtures are produced - helioxes and trimixes.

Deeper than 80 m

Complex mixtures It is worth saying here that compression and decompression at pressures of tens and hundreds of atmospheres takes a long time. So much so that it makes the work of industrial divers - for example, when servicing offshore oil platforms - ineffective. The time spent at depth becomes much shorter than long descents and ascents. Already half an hour at 60 m results in more than an hour of decompression. After half an hour at 160 m, it will take more than 25 hours to return - and yet the divers have to go lower.

Therefore, deep-sea pressure chambers have been used for these purposes for several decades. People sometimes live in them for whole weeks, working in shifts and making excursions outside through the airlock compartment: the pressure of the respiratory mixture in the “dwelling” is maintained equal to the pressure of the aquatic environment around. And although decompression when ascending from 100 m takes about four days, and from 300 m - more than a week, a decent period of work at depth makes these losses of time completely justified.

Methods for prolonged exposure to high-pressure environments have been developed since the mid-twentieth century. Large hyperbaric complexes made it possible to create the required pressure in laboratory conditions, and the brave testers of that time set one record after another, gradually moving to the sea. In 1962, Robert Stenuis spent 26 hours at a depth of 61 m, becoming the first aquanaut, and three years later, six Frenchmen, breathing trimix, lived at a depth of 100 m for almost three weeks.

Here, new problems began to arise associated with people's long stay in isolation and in a debilitatingly uncomfortable environment. Due to the high thermal conductivity of helium, divers lose heat with each exhalation of the gas mixture, and in their “home” they have to maintain a consistently hot atmosphere - about 30 ° C, and the water creates high humidity. In addition, the low density of helium changes the timbre of the voice, seriously complicating communication. But even all these difficulties taken together would not put a limit to our adventures in the hyperbaric world. There are more important restrictions.

Below 600 m

Limit In laboratory experiments, individual neurons growing “in vitro” do not tolerate extremely high pressure well, demonstrating erratic hyperexcitability. It seems that this significantly changes the properties of cell membrane lipids, so that these effects cannot be resisted. The result can also be observed in the human nervous system under enormous pressure. He begins to “switch off” every now and then, falling into short periods of sleep or stupor. Perception becomes difficult, the body is seized with tremors, panic begins: high-pressure nervous syndrome (HBP) develops, caused by the very physiology of neurons.

In addition to the lungs, there are other cavities in the body that contain air. But they communicate with the environment through very thin channels, and the pressure in them does not equalize instantly. For example, the middle ear cavities are connected to the nasopharynx only by a narrow Eustachian tube, which is also often clogged with mucus. The associated inconveniences are familiar to many airplane passengers who have to tightly close their nose and mouth and exhale sharply, equalizing the pressure of the ear and the external environment. Divers also use this kind of “blowing”, and when they have a runny nose they try not to dive at all.

Adding small (up to 9%) amounts of nitrogen to the oxygen-helium mixture allows these effects to be somewhat weakened. Therefore, record dives on heliox reach 200-250 m, and on nitrogen-containing trimix - about 450 m in the open sea and 600 m in a compression chamber. The French aquanauts became - and still remain - the legislators in this area. Alternating air, complex breathing mixtures, tricky diving and decompression modes back in the 1970s allowed divers to overcome the 700 m depth bar, and the COMEX company, created by students of Jacques Cousteau, made the world leader in diving maintenance of offshore oil platforms. The details of these operations remain a military and commercial secret, so researchers from other countries are trying to catch up with the French, moving in their own ways.

Trying to go deeper, Soviet physiologists studied the possibility of replacing helium with heavier gases, such as neon. Experiments to simulate a dive to 400 m in an oxygen-neon atmosphere were carried out in the hyperbaric complex of the Moscow Institute of Medical and Biological Problems (IMBP) of the Russian Academy of Sciences and in the secret “underwater” Research Institute-40 of the Ministry of Defense, as well as in the Research Institute of Oceanology named after. Shirshova. However, the heaviness of neon showed its downside.

It can be calculated that already at a pressure of 35 atm the density of the oxygen-neon mixture is equal to the density of the oxygen-helium mixture at approximately 150 atm. And then - more: our airways are simply not suitable for “pumping” such a thick environment. IBMP testers reported that when the lungs and bronchi work with such a dense mixture, a strange and heavy feeling arises, “as if you are not breathing, but drinking air.” While awake, experienced divers are still able to cope with this, but during periods of sleep - and it is impossible to reach such a depth without spending long days descending and ascending - they are constantly awakened by a panicky sensation of suffocation. And although the military aquanauts from NII-40 managed to reach the 450-meter bar and receive well-deserved medals of Heroes of the Soviet Union, this did not fundamentally solve the issue.

New diving records may still be set, but we have apparently reached the final frontier. The unbearable density of the respiratory mixture, on the one hand, and the nervous syndrome of high pressure, on the other, apparently put the final limit on human travel under extreme pressure.

The depth of immersion of the pump into the well determines the quality, uninterrupted supply of water, the service life of the device, and sometimes the hydraulic structure itself. It is better to entrust the calculation of the minimum installation depth of a well pump to specialists. It depends on the flow rate of the source and the performance of the pump. It is necessary to mount the device in such a way as to prevent dry operation. At the same time, the distance from the bottom must be sufficient so that sand and silt are not sucked into the inlet pipe along with water.

Variety of submersible pump models

Permissible limits for the installation depth of a well pump

• the device should not come into contact with the bottom of the hydraulic structure;
• the device must be immersed at least 1 meter below the water surface.

Why is there a limit on depth relative to the water surface? This is due to the operating features of the device. Firstly, it is necessary to provide conditions under which dry running is impossible. Secondly, the cooling of the electric motor is carried out due to the working environment. There must be enough water so that the device does not overheat, otherwise difficulties may arise with pumping the liquid.

The limitation on placement above the bottom exists because suspended solids are most abundant in the bottom water layer. This applies to all hydraulic structures, but is especially true for sand wells. There are soil particles, sand, and silt in the water. If the pump is lowered too low, it will pump dirty water that is unsuitable for drinking and domestic use. If grains of sand get into the pump mechanism, they can damage it and cause it to fail. Therefore, it is advisable to place the device 2-6 m from the bottom.

Scheme of installing a pump in a well

How to take into account the dynamic level of a well

The dynamic level is the distance from the water surface to the surface of the earth. The value is taken into account when the level is minimal. This is important because The amount of water in the well is not constant. It may vary depending on the season and the intensity of water intake from the horizon through hydraulic structures drilled into this formation. Dynamic level indicators are indicated in the well passport. They may vary depending on the type and design of the pump. The higher the pump performance, the greater its immersion depth should be.

Practical Method for Determining the Required Depth

In practice, a pump is installed in a well like this:

• First, the device is lowered on a safety rope to the entire depth of the water well.
• When the device reaches the bottom, it is raised 1.5-2 m and temporarily fixed.
• After this they run it to check the operation.
• If the device operates normally, there are no comments or complaints, it is finally fixed in this position.

Note! The method is used only in cases where the depth of the pump in the well is up to 16 meters. It is not suitable for deep wells.

Usually our compatriots try to do all the work themselves. Installing water-lifting equipment does not seem too difficult, so many people do it on their own. When installing, remember that mistakes can result in unplanned repairs or even replacement of the pump. Therefore, if you have any doubts about the correctness of the actions being performed, consult a specialist.

Diving refers to the transition of a submarine from the surface to the submerged position. The same type of maneuver includes changing the depth of immersion when the ship goes to lower levels of the water column. When diving, special main ballast tanks are filled with water. While submerged, the boat can change its diving depth using horizontal rudders.

A typical dive is carried out in two stages and is carried out most often in areas with poor maneuvering conditions, for training purposes, and also at the discretion of the ship's commander. In this case, the end ballast tanks are filled first, and then the middle group of tanks. During a normal maneuver, the tank intended for rapid submersion remains empty.

The dive is preceded by preparation: the holds are drained, the compartments are ventilated, and the condition of the battery is checked. The dive point is selected in advance. When approaching it, the boat's progress stops. The process of going underwater is preceded by a special command, according to which the personnel take their places corresponding to the official schedule.

Observation of the surface situation is transferred to the conning tower and is carried out using radio equipment or a periscope. Having completed the dive, the boat goes into the so-called positional position. Now the team is checking the ship's compartments to determine how well the boat's hull is sealed.

How to perform an emergency dive

In a combat situation, there are times when the boat needs to be transferred to an underwater position as quickly as possible. To do this, usually only one combat shift is involved. The signal for an urgent dive can be given by the ship's commander or the watch officer. Hearing the command “All down,” the crew on the bridge immediately descends into the submarine and takes their places, carrying out incoming commands.

At the same time, the diesel units and nose clutches are switched off, and the outboard openings and shafts through which air is supplied to the diesel engines are sealed. The watch officer closes the upper control room. The main ballast tanks begin to be filled and the electric motors are turned on. The rapid immersion tank is purged and prepared for the maneuver.

During an urgent dive, the crew pays special attention to constantly checking the position of the ship. This is necessary so that the increasing trim does not exceed the permissible limit, since in this case the boat may well lose buoyancy. Here, the experience of the ship’s commander, as well as the clear and coordinated work of the crew, plays a huge role.

One of the most important characteristics of a submarine is stealth, which largely depends on the depth of the dive. A submarine at great depth is less noticeable and therefore less vulnerable, and the blow it inflicts will be all the more unexpected and inevitable.

How submarines dive

The evolution of the submarine fleet is a gradual dive to greater depths. If during the First and Second World Wars it was limited to 80-100 and 100-150 meters, respectively, today this figure has increased 3-5 times.

How does immersion occur? On the surface, the submarine is not much different from an ordinary ship, if you do not take into account its specific appearance. Immersion occurs due to the intake of ballast - sea water - into the tanks. The containers are located between lightweight and durable housings.

Ascent is carried out “in reverse order” - by blowing ballast. Water is squeezed out of the tanks by a powerful stream of compressed air. After complete immersion, the depth at which the boat is located is regulated by special rudders.

Immersion depth characteristics

The ability of a submarine to dive is characterized by two main indicators - working (operational) and maximum depth. In the first case, we are talking about the depth to which the boat can dive without any restrictions throughout its entire service life.

The maximum immersion depth indicates the limit below which the destruction of the casing and the entire structure can begin. Usually, immediately after launching, the submarine is sent to the maximum depth, where it is “run in” for some time. This indicator is individual for each type of submarine.

The absolute record holder for maximum immersion to this day remains the Soviet nuclear submarine Komsomolets, which “dive” to almost 1030 meters in 1985. Alas, her fate later turned tragic. Four years later, as a result of a fire that led to irreversible damage to the hull, she sank in the Norwegian Sea.

Depth - salvation or destruction

Lying low, sneaking up on the enemy unnoticed and delivering a devastating blow to him, and then disappearing unnoticed - this can be described as the tactics of a submarine. And depth is one of the most important factors here.

However, it also poses a colossal danger. At a depth of just 50 meters, the conning tower exit hatch with an area of ​​2 m² experiences a pressure of almost 60,000 kg. It is not difficult to calculate how much this figure will increase at a depth of 300-400 meters.

As a rule, two pairs of horizontal rudders - stern and bow - are responsible for the controllability of the submarine in the vertical plane. Depending on their position, the boat receives trim to the bow or stern. The task of the commander and crew is to carry out the necessary maneuvering within the technical capabilities of the boat, so that, if this happens, the maximum, maximum dive does not turn out to be the last.

Features of Russian and US nuclear submarines

The main differences lie in the "architecture". American submarines are single-hulled: a single, streamlined hull resists pressure. In contrast, Soviet and later Russian nuclear submarines are a kind of “matryoshka”, where under the outer streamlined light hull there is a durable inner one. The real record holder for the number of hulls is the famous Typhoon (project 941). Five durable ones are placed inside the lightweight body.

According to experts, double-hulled boats are more durable, although they are heavier. For example, the Typhoon's rubber soundproofing coating alone weighs 800 tons, which is slightly more than the entire American nuclear submarine NR-1.

Prospects for the Russian nuclear submarine fleet

Over the past 4 years, the Russian Navy has been replenished with four modern nuclear submarines: Severodvinsk (Ash Ave) with working and maximum diving depths of 520 and 600 m, respectively, Vladimir Monomakh - 400 and 480 m, Yuri Dolgoruky - 400 and 450 m, “Alexander Nevsky” - 400 and 480 meters. There are 11 more nuclear submarines of the Borey-A and Borey-A projects in line.

However, immersion depth is not their only advantage. Today, low noise levels are becoming much more important. According to experts, here Russia has taken a leading position in the world.