Breathing under water

Application of the Henry - Dalton law, method of separation dissolved gases

Contents

  1. 1. Introduction
  2. 2. Methodology
  3. 3. Initial information
    1. 3.1 Natural laws
    2. 3.2 Water and gases
    3. 3.3 Cavitation and centrifugal pump
    4. 3.4 Human respiration
      1. 3.4.1 Mechanics of respiration
      2. 3.4.2 Gas exchange in lungs and tissues
      3. 3.4.3 Respiration underwater
  4. 4. Water degassing
    1. 4.1 Equipment
    2. 4.2 Principle
    3. 4.3 Advance
    4. 4.4 Results
  5. 5. Appliance
    1. 5.1 Parameters
    2. 5.2 Centrifugal pump
    3. 5.3 Scheme
    4. 5.4 Exploitation
  6. 6. Conclusion

1. Introduction

I began to think about respiration under water when I was putting water into an injection. I noticed an amazing phenomenon I had never seen before. I saw bubbles of air creating in the injection.
Watch the movie if you don’t want to get wet yourself » at http://vizualbod.com/f/water/film.swf

I realized immediately that this is not a common sense explainable phenomenon. I realized, I had degassed water and separated dissolved gases. The same stuff that fishes breath. It was really an exciting reflection so I decided to invest more time there. I realized I could breathe air dissolved in water.

The aim of the project is to develop an appliance which allows to a man to breathe air extracted from water. In other words, aim of the project is to explain physical mechanism of degassing water and to construct an efficient design to supply a man with breathable healthy fresh air under water. Build it. Test it. And finnaly, find other ways of using extracted gases and degassed water.

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Frantisek Malina [read: Frank Malina]

8 Halsall Avenue
Warrington
WA28EY
United Kingdom

Phone: +44-785-730-9211

Copyright © 2004 František Malina. Some rights reserved.

2. Methodology

The project has a definite aim so I searched and studied in different sources only for specific information which is connected to the topic.

The design of an appliance for separating natural water components is still abstract. Appliance is still being developed at a theoretical level.

Experiment: The way of obtaining and checking information about the solution of gases is described in the chapter 4. Water degassing in the section 4.3 Advance.

3. Initial information

3.1 Natural laws

Dalton’s law
is physical law that states that the total pressure exerted by a homogeneous mixture of gases is equal to the sum of the partial pressures of the individual gases. The partial pressure of a gas is the pressure it would exert if all the other gases in the mixture were absent.
It is principle that each gas in a mixture of gases exerts a pressure proportionately to the percentage of the gas and independently of the presence of the other gases present. It is also called law of partial pressures.
Henry’s law
is chemical law stating that the amount of a gas that dissolves in a liquid is proportional to the partial pressure of the gas over the liquid, provided no chemical reaction takes place between the liquid and the gas. It is named after William Henry (1774 - 1836), the English chemist who first reported the relationship.
The mass of a gas which will dissolve into a solution is directly proportional to the partial pressure of that gas above the solution.
The pressure of the gas above a solution is proportional to the concentration of the gas in the solution.
When a gas is in contact with the surface of a liquid, the amount of the gas which will go into solution is proportional to the partial pressure of that gas. A simple rationale for Henry’s law is that if the partial pressure of a gas is twice as high, then on the average twice as many molecules will hit the liquid surface in a given time interval, and on the average twice as many will be captured and go into solution.
For a gas mixture, Henry’s law helps to predict the amount of each gas which will go into solution, but different gases have different solubility and this also affects the rate. The constant of proportionality in Henry’s law must take this into account.
For example, in the gas exchange processes in respiration, the solubility of carbon dioxide is about 22 times that of oxygen when they are in contact with the plasma of the human body.
Bernoulli’s principle
is a statement of the conservation of energy in a form useful for solving problems involving fluids. For a non-viscous, incompressible fluid in steady flow, the sum of pressure, potential and kinetic energies per unit volume is constant at any point.
Bernoulli’s principle states that as the speed of a moving fluid increases, the pressure within the fluid decreases.
Boyle’s law
is the principle that at a constant temperature the volume of a confined nameeal gas varies inversely with its pressure.

3.2 Water and gases

Natural water is a gas solution.

Vernadskij, V. I.

We should consider natural water to be a gas-water solution, where exists an equilibrium of water and gases.

Bondarenko, N. F. - Gak, J. Z.: Elektromagnitnyje javlenija v prirodnych vodach. Leningrad, Gidrometeoizdat 1984, p.7

It means that dissolving of gases in water decreases with a rise in temperature and increases with part pressure above solution. Water 293.15K contains this amount of gases: nitrogen 16.84 mg/l, oxygen 9.07 mg/l, argon 0.43 mg/l, carbon dioxide 0.36mg/l.

3.3 Cavitation and centrifugal pump

A fluid vaporizes when its pressure gets too low, or its temperature too high. This problem is connected with low pressure pumps. Gas binding of a centrifugal pump is a condition where the pump casing is filled with gases or vapours to the point where the impeller is no longer able to contact enough fluid to function correctly. The impeller spins in the gas bubble, but is unable to force liquid through the pump. This can lead to cooling problems for the pump’s packing and bearings.

Centrifugal pumps are designed so that their pump casings are completely filled with liquid during pump operation. Most centrifugal pumps can still operate when a small amount of gas accumulates in the pump casing, but pumps in systems containing dissolved gases that are not designed to be self-venting should be periodically vented manually to ensure that gases do not build up in the pump casing.

3.4 Human respiration

3.4.1 Mechanics of respiration

Ventilation
Movement of air into and out of lungs
Air moves from area of higher pressure to area of lower pressure
Pressure is inversely related to volume
External respiration
Gas exchange between air in lungs and blood
Transport of oxygen in the blood and carbon dioxide in the lungs
Internal respiration
Gas exchange between the blood and tissues
Transport of oxygen in the tissues and carbon dioxide in the blood
Pulmonary Volumes
Tidal volume
Volume of air inspired or expired during a normal inspiration or expiration - cca 500 ml
Inspiratory reserve volume
Amount of air inspired forcefully after inspiration of normal tidal volume - cca 2500
Expiratory reserve volume
Amount of air forcefully expired after expiration of normal tidal volume - cca 1000 ml
Residual volume
Volume of air remaining in respiratory passages and lungs after the most forceful expiration - cca 1500 ml
Residual volume Vital capacity
(cca 1.5 l) Expiratory reserve volume (cca 1 l) Tidal volume cca (0.5 l) Inspiratory reserve volume (cca 2.5 l)
Pulmonary Capacities
Inspiratory capacity
Tidal volume plus inspiratory reserve volume
Functional residual capacity
Expiratory reserve volume plus the residual volume
Vital capacity
Sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume
Total lung capacity
Sum of inspiratory and expiratory reserve volumes plus the tidal volume and residual volume
Minute and Alveolar Ventilation
Minute ventilation
Total amount of air moved into and out of respiratory system per minute, at rest 7 -9 l
Respiratory rate or frequency
Number of breaths taken per minute, at rest 14 -18
Anatomic dead space
Part of respiratory system where gas exchange does not take place
Alveolar ventilation
How much air per minute enters the parts of the respiratory system in which gas exchange takes place

3.4.2 Gas exchange in lungs and tissues

Physical Principles of Gas Exchange
Diffusion of gases through the respiratory membrane
depends on: membranes thickness, the diffusion coefficient of gas, surface areas of membrane and partial pressure of gases in alveoli and blood.
Relationship between ventilation and pulmonary capillary flow
Increased ventilation or increased pulmonary capillary blood flow increases gas exchange.
Physiologic shunt is deoxygenated blood returning from lungs.
Air Gases in %
O 2 CO2 N 2
atmospheric 20.92 0.04 79.04
alveolar 14.1 5.6 79.7
exspirated 16,3 4.0 79.3
Oxygen and Carbon Dioxide Diffusion Gradients
Oxygen
Moves from alveoli into blood. Blood is almost completely saturated with oxygen when it leaves the capillary
Oxygen moves from tissue capillaries into the tissues
Carbon dioxide
Moves from tissues into tissue capillaries
Moves from pulmonary capillaries into the alveoli

3.4.3 Respiration underwater

Revolution in a history of a Diving has taken place in 1943. Jacques-Yves Cousteau and Emile Gagnan have devised the first working vehicle with an open-air circuit of respiration (process by which organism utilizes oxygen from its environment) Diving with compressed air or other gas mixture which is taking place in balloons, using by the diver (SCUBA-Diving). In essence there are two types of aqualung: with the opened and closed cycle of respiration (the systems with an open circuit of respirations ejecting all air on external medium, are popular in the diving for entertainment).

Systems with the closed cycle of respiration, in which inhaled air acts back in a respiratory contour, and after absorption of a carbon dioxide and adding of oxygen, again will be utilized for breathing. These systems were widely utilized before occurrence of systems with an open circuit of respiration, and were utilized in the fundamental militarian divers, which tried to avoid occurrence of bubbles on a surface of water.

Water is not a natural environment for a man. The main limiting factors are:

  1. Exigency of breathing
  2. Hydrostatic pressure

If a man wants to survive in a water environment, it is necessarily to eliminate these limitations.

4. Water degassing

A stimulated separation of dissolved gases from natural water.

4.1 Equipment

Experiment
  1. Injection volume 20 ml or more
  2. needles (various diameters)
  3. thermometer
  4. measure of separated gas volume (capillary tube)
  5. pipette
  6. tank with water
Observation

Sparkling water

4.2 Principle

Hypothesis for experiment
Big difference between pressure in needle and pressure in injection results in acquiring a bigger volume of gas.
Hypothesis for observation
Liquid solution of water, gases and another substances has an inner structure. And so releasing of gases depends on more factors than just partial pressure and temperature.

4.3 Advance

Experiment

Water degassing using injection

  1. Sink injection
  2. Admission water, low pressure in injection - near vacuum, cavitation
  3. Admission water, low pressure in injection - rising of pressure, cavitation
  4. Rising of pressure, reducing of bubble volume
  5. Rising of pressure, reducing of bubble volume
  6. End, gas is now in gas phase
  1. Measuring of separated gas volume
  2. Notation values
  3. Evaluation and interpretation
Observation

Observation of solution behaviour in different conditions.

4.4 Results

Using this primitive method we can extract 1 volume percent of dissolved gases into gas phase. We can see that bigger difference of pressure (using thin needle) has not better effect than fast putting water without needle.

First hypothesis was disproved by evidence. The fact that water is not an nameeal liquid it an explanation of such a behaviour.

Second hypothesis was established. The degassing process depends on variety of conditions. Foreign-matter content - “condensing” cores for gases, free surface of the level, motion of the liquid in veneer, material of the tank. We can see that abrasive materials caused increasing of degassing speed. Abrasive materials have large free surface where gases can condense. Intro change in partial pressure of gases above solution volume of eliminate gases per time is linear depending on water free surface.

5. Appliance

5.1 Parameters

  1. Human respiration: Total amount of air moved into and out of respiratory system per minute, at rest and normal pressure 7-9 l
  2. We are able to obtain from water 1 volume percent of dissolved gases into the gas phase so we have to degas at least 700-900 l of water per minute to supply a man with respiratory gases on the level.
  3. Hydrostatic pressure and stress increases body oxygen requests. Depth can increases the amount of air required by the body on such a level that no pump could manage it. But there are still systems with a closed cycle of respiration, in which inhaled air is returned in a respiratory contour, and after absorpting carbon dioxide and adding of oxygen, again the air can be utilized for breathing. Such combination of appliances could maximize divers limited work time.

5.2 Centrifugal Pump

Our requests are strong flow, lower pressure and low consumption of energy. Jet centrifugal pump is the best type of pump for our aim.

Wheels = (V b / 0.01) / V g

Wheels
number of wheel per time
V b
necessary volume for breathing per time
0.01
constant, which express volume of gases dissolved in water we are able to separate (it depends from temperature and pressure of gages above the water solution)
V g
geometrical volume of pump

5.3 Scheme

Water degassing appliance - scheme

  1. Suction
  2. First centrifugal pump
  3. Degas tank - Low pressure centre
  4. Centrifugal separating turbine
  5. Gas
  6. Second centrifugal pump
  7. Degassed water

5.4 Exploitation

Besides the obtained gas this appliance makes another product. The degassed water is characterised by its excellent biological attributes. Its biological activity is much stronger than activity of natural water. It makes molecules of water easy to penetrate phospholipid membranes of cells.

The degassed water was successfully tested in laboratory conditions by stimulation of various plants to increase its fertility and improve the quality of production.

Zelepuchin, V.D.; Zelepuchin I.D.: Kluc k zivoj vode. Alma - Ata, Kajnar 1982, p.26

The method that was used for water degassing (boil) is much more expensive than separating by the lower pressure, therefore it is also useful for agriculture.

The appliance would create two products, and so there are two main areas of applications.

The first is hypotonic degassed water which is relevant for agriculture because plant growth is improved when watered with degassed water also animals put on weight better. It is beneficial for human health when used right.

The second is to clean water by removing gasses dissolved in it and analogically to supply of respiratory gas for breathing under water. We can remove dissolved polluting substances like methane, ethane and chlorine or to kill micro-organisms by lysing of their membranes.

6. Conclusion

The aims of the project are still not complete. The appliance that is able to supply the respiratory gas for man extracted from water and meanwhile to ensure a reactive motion under water is not yet a reality but probably the first step has been made towards its realization.

Using this appliance would be the first limiting factor for accommodation in water the number of energy.

Its advantage is that two problems are solved. The first one is a gas supplement and the second one is a simplification of the motion of a diver or submarine crew. The various modifications of the appliance can be used in different branches of manufacturing and agriculture, where degassed water is needed or it is not possible to obtain air by another method.

Literature

Only primary resources are published. Phonetic transcription from cyrilician.

Bondarenko, N. F. - Gak, J. Z.: Elektromagnitnyje javlenija v prirodnych vodach. Leningrad, Gidrometeoizdat 1984, p.7

Zelepuchin, V.D.; Zelepuchin I.D.: Kluc k zivoj vode. Alma - Ata, Kajnar 1982, p.26

Date

Original published in Slovak language in April, 2005.

Last update: October 17, 2008