Oxygen equipment for aviation

OREANDA-NEWS. The lack of oxygen in the air can cause euphoria, with the consequent loss of consciousness. To avoid this, it is necessary to use special aviation oxygen masks, devices and systems, manufactured in particular by Aviation Equipment.

All trifles and details are worthy of attention in ensuring pilots and passengers of planes with oxygen. Students of aviation schools thoroughly trained to use aircraft equipment for breathing and prevent the emergence of any signs of oxygen starvation.

Due to constant mixing, the composition of air within the troposphere and lower stratosphere is constant. Why did the people at the height of not enough oxygen when its 21% concentration in the air is the same everywhere?

In whole that means that, the amount of oxygen is not so important for breathing as its partial pressure, i.e. the pressure that would have oxygen in the case if it had occupied the whole volume in a mixture with other gases. The partial pressure of oxygen in the air decreases with each meter lift. Thus, it is equal to 160 mm of mercury on the ground, but 42 mm of mercury at 10 thousand meters height.

The lack of oxygen in the inspired air makes in human bodies a number of changes, called "altitude sickness". Of course, it was known long before the appearance of aviation, it was observed in climbers and called "mountain".

"High mountains are uninhabited because of it - explains MD, professor, medical colonel Konstantin Platonov in his book "Man in flight."- The highest mines in the world developed at Quilchi in the Andes, located at an altitude of 5700 m. People working there cannot live on such height. Every day they have to go down to the village, located at an altitude of 5250 m. It is one of the most highly situated villages in the world."

Issue of altitude sickness became particularly acute while development of aviation. Besides, rise of aircraft goes very quickly now.

The first scientific description of altitude sickness did Gaston Tissandier, the sole survivor of the pilot balloon "Zenith", rising in Paris April 15, 1875 with a crew of three.

"At an altitude of 7000 meters, Sivel started from time to time to close his eyes, - said in the balloonist notes. - My hands are numb. The weakness was so great that I could no longer turn my head to the side of both my fellow travellers. I wanted to breathe oxygen, but I could not lift a hand to the tube... I want to shout: "We have reached 8000 m," but my tongue was as if paralyzed. Then, closing my eyes, I feel myself exhausted and lose consciousness."

"Zenith" catastrophe has attracted the attention of Ivan Sechenov and forced him to start researching to lay the foundations of high-altitude physiology. He identified the characteristics of hypoxemia: lethargy, drowsiness, difficulties in distribution and switching of attention.

Sometimes, excitement, elation, lowering the critical relationship of man to what is happening and reassessment of his/her forces called in medicine euphoria observed instead of drowsiness. This state is the most dangerous for the pilot because deceptive, fainting may occur suddenly, catching a person by surprise.

This is what was said about in the notes of Tissandier: "The state at an altitude of about 7,500 meters is extraordinary. Body and mind imperceptibly weaken, but the process is not becoming aware of. There is no suffering. On the contrary, there is an inner joy, as if from the radiance that spilled around. All becomes indifferent. The human being does not think about disastrous situation, nor the danger. Sudden and irresistible dizziness comes at the last moment, just before fainting."

The following established today: flying at altitudes above 5000 meters can be or only using devices that provide oxygen supply to the pilot, or in pressurized cabins and spacesuits. To increase the percentage of oxygen in the inspired air serves a special oxygen equipment. Each plane rising above 4000 meters is now equipped with it.

Oxygen equipment consists of a cylinder with reserve oxygen; pipeline tubes connecting the cylinder to the device; oxygen device; a hose and a mask to supply of oxygen from the device to respiratory organs of the human being.

Oxygen devices with masks of open types are far from perfect, so they are used only for training and transport airplanes, as well as a means of salvation (knapsack parachute oxygen devices), when the use of the oxygen device is short.

More economical oxygen devices such as "lung machine" with a valve mask tightly adjacent to the face set in modern aircraft. Oxygen is fed into them automatically only during inspiration, and feeding is stopped at the beginning of exhalation.

Breathing at altitudes above 12,000 meters even pure oxygen has not provided the necessary oxygen partial pressure. It is therefore necessary to use improved devices, providing oxygen overpressure. They are used only in conjunction with a special compensating clothing consisting of a pneumatic vest, tight-fitting chest and automatically creating a counter pressure to overpressure, pneumatic pants and sleeves, which are squeezing the veins of the limbs and preventing stagnation of venous blood. Breathing under pressure inside of the compensating clothing requires special exercises, strengthening muscles of respiration.

So today the pilot equipment usually contains the oxygen mask (KM) put on the crash helmet (ZSh) or full pressure helmet (GSh), and the pressure suit (VKK) or a space suit. Fixed or mobile Fixed or mobile oxygen stations are on most of airdromes. Oxygen is obtained from atmospheric air by deep cooling, liquefying and separating into nitrogen and oxygen.

ZVEZDA RD & PE, OJSC (Aviation Equipment, OJSC (A holding company), a part of Rostec Corporation, is one of the main Russian producers of such systems. The holding produces oxygen systems, oxygen breathing devices, fire extinguishers and checkout equipment for all types of military and civilian aircraft and helicopters. It includes:

- Oxygen systems for the crew:

BKO-5K is a block of oxygen equipment, which includes a mask with a mechanism for adjusting the force of attraction to the face, which is especially important when performing a long flight; KDA-15 is an oxygen breathing apparatus, which is used in flights at altitudes up to a practical ceiling of the airplane, including a depressurized cabin and when leaving the aircraft (used on such aircrafts as Su-27, Su-30, Su-34); KKO-LS-2 is easily removable set of oxygen equipment to fly at altitudes of up to 6 km (installed on Mi-24, Mi-26, Mi-28, and Mi-35M helicopters).

- Emergency oxygen systems for passengers: AKB-204, designed for a case of depressurization of an airplane (installed on civilian aircrafts Tu-204 and Tu-214).

- Portable oxygen supply units (BKP) designed for relocation along the aircraft in the event of smoke generation (used on civil aircrafts An-148, Il-96, Tu-204, and Tu-214).

- Stationary oxygen plants (KU-7 and KU-8) designed to test operation of all aviation oxygen devices (they can be used in all climatic zones directly on and out of a plane).