Mathematics
Pyrotechnic composition for producing oxygen. Review of “Live. What is an oxygen candle? Oxygen candles for astronauts

Pyrotechnic composition for producing oxygen. Review of “Live. What is an oxygen candle? Oxygen candles for astronauts

"Use of chemical contradiction in an innovative project: oxygen candle"

Volobuev D.M., Egoyants P.A., Markosov S.A. CITC "Algorithm" St. Petersburg

Annotation.

IN previous work we introduced the concept of chemical contradiction (CP), which is resolved by introducing or removing a substance from the composition. In this work, we analyze the algorithm for solving HP using the example of one of the innovative projects.

Introduction

Chemical contradictions quite often arise during the implementation of innovative projects, but are not formulated explicitly, so the success of such projects is determined only by the erudition and scientific training of the inventive team. The classification of methods for solving HP given in our previous work allows us to propose here a step-by-step algorithm for solving HP, which is designed to systematize scientific research and, perhaps, facilitate the presentation of the results of the work to people who are far from such a search.

The need for a HP solution, as a rule, arises at the final (verification) stage of an innovation project. Possible areas of research, areas of acceptable solutions, and limitations were identified at previous stages of the project. The proposed algorithm does not claim to be complete and should be refined as projects progress.

Step-by-step algorithm for solving HP

Formulate HP
Choose a solution: (1) Introduction of additional substance or (2) separation of substance from the composition. Separation usually requires transferring the substance into a liquid or gas phase. If, according to the conditions of the problem, the substance is in the solid phase, method (1) is selected
Specify the class of substances or group of technologies for (1) or (2) respectively.
Use function-oriented search ( FOP) to identify technology that is as close as possible to the desired one. The search is mainly focused on scientific articles and patents with detailed description technologies.
Use property transfer(PS) from found objects to improved ones.
Select the composition to be optimized based on the results of the FOP and the limitations of the project.
Plan a series of experiments and, if required, build a laboratory facility to optimize the composition
Conduct experiments and display results optimization on the phase diagram or composition triangle
If the optimization result is unsatisfactory, return to point 3 and modify the composition or finish work.

Example 1. Oxygen plug (Catalyst).

Context: This problem arose with the invention of the “smokeless cigarette” - the cigarette must burn in a sealed case, supplying the smoker with smoke only when inhaling.

Restrictions: the case should be small (carried in a pocket) and cheap.

It should be noted that a cigarette in a case goes out in a few seconds due to oxygen burnout, so the central task of the project was considered to be the development of a cheap (disposable) chemical oxygen generator.

Possible Solution: Oxygen comes from the decomposition of Berthollet salt. The temperature and reaction rate are reduced by the addition of a catalyst (Fe 2 O 3), which lowers the activation threshold.

Progress of the solution step by step:

HP formulation: Oxygen gas must be in the combustion zone to support combustion and should not be in the combustion zone to avoid thermal explosion.
Solution: We choose direction (1) - adding an additional substance, since, based on the conditions of the problem, we must store the oxidizing agent in a solid state of aggregation.
Clarification of the class of substances: Substances that release or absorb significant amounts of energy.
FOP result: a system existing on the market was found that performs the function of generating pure oxygen - this is the so-called. an oxygen candle widely used in passenger aircraft to provide emergency oxygen for the passenger's breathing. The device of an oxygen candle is quite complex (see, for example,), and usually includes a buffer storage tank with a valve system, because oxygen is released faster than the consumer needs.
Transfer properties: It is necessary to transfer the ability to generate oxygen from the found oxygen candle to the desired mini-candle. The use of buffer capacity in our device is unacceptable due to the restrictions imposed, so further work was reduced to optimization chemical composition candles.
Choosing the composition: A dual fuel-oxidizer system with a shifted equilibrium towards the oxidizer was chosen as the base one. Berthollet salt acted as an accessible oxidizing agent, and starch acted as a fuel and binder.
Design of experiments and laboratory setup: It is necessary to conduct a series of experiments on a mixture of starch and Berthollet salt with different concentrations of starch, measure the reaction time and oxygen yield. For this purpose, it is necessary to develop and assemble a laboratory installation with the possibility of remote electrical ignition, visual monitoring of reaction time and quantitative assessment of oxygen concentration. The assembled installation is shown in Fig. 1.
Experimental results and conclusions: The first experiments showed that in this dual system the desired solution is absent - with small additions of fuel, the lit candle goes out in the case; with an increase in the amount of fuel, the combustion of the candle occurs unacceptably quickly - in one or two seconds instead of the required units of minutes => Return to point 3. Steps subsequent repeated iteration are indicated by the index "+".
Solution+: addition of additional substance.
Clarification of the class of substances+: Catalysts
FOP and PS+: A study of the structure of the match allows us to conclude that the catalysts for the decomposition of Berthollet salt are MnO 2 and Fe 2 O 3
Composition selection+: a third substance was mixed into the base composition - iron oxide (Fe 2 O 3), which simultaneously acts as a catalyst for the decomposition of berthollet salt, lowering the reaction activation threshold and as an inert filler that removes heat from the reaction zone.
Experimental Design and Lab Setup+: the same (Fig. 1). The effect of adding a catalyst to the mixture is not obvious in advance, so the addition of the catalyst began with small amounts and in compliance with safety precautions.
Experimental results and conclusions+: Due to the two-stage nature of the decomposition reaction of berthollet salt, the addition of a catalyst noticeably reduced the temperature and, accordingly, the reaction rate.

Rice. 1. Laboratory installation for determining combustion parameters and oxygen concentration in the combustion products of an oxygen candle.

The addition of a catalyst, in addition, made it possible to significantly reduce the limiting amount of fuel in the mixture at which a stable reaction is still maintained. A control additive to the basic two-component system of inert filler (aerosil SiO 2) did not lead to noticeable changes in the combustion rate.

The invention relates to oxygen generators for breathing and can be used in breathing apparatus for personal use, used in emergency situations, for example when extinguishing fires. In order to reduce the rate of oxygen generation and increase reliability during long-term operation, a pyrochemical oxygen generator containing pressed blocks of a solid oxygen source with transition ignition elements, an initiating device, thermal insulation and a filter system, placed in a metal case, equipped with an outlet pipe for oxygen, has solid source blocks oxygen in the form of parallelepipeds, while a composition of sodium chlorate, calcium peroxide and magnesium is used as a solid source of oxygen. Transitional ignition elements are prepared from a mixture of calcium peroxide with magnesium and are pressed in the form of tablets either into the end or into the side edge of the side, and the blocks themselves are laid in layers and in a zigzag manner in each layer. 1 z. p. f-ly, 2 ill.

The invention relates to oxygen generators for breathing and can be used in breathing apparatus for personal use, used in emergency situations, for example when extinguishing fires. A pyrochemical oxygen generator is a device consisting of a housing, inside of which there is a composition capable of releasing oxygen through a self-propagating pyrochemical process: an oxygen candle, an ignition device for initiating combustion of the candle, a filter system for purifying the gas from foreign impurities and smoke, and thermal insulation. Through the outlet pipe, oxygen is supplied to the point of consumption through the pipeline. In most known oxygen generators, the spark plug is made in the form of a cylindrical monoblock. The burning time of such a candle does not exceed 15 minutes. Longer operation of the generator is achieved by using several blocks (elements) laid so that their ends touch. When the combustion of one block ends, the thermal impulse initiates the combustion of the next element of the candle, and so on until it is completely used up. For more reliable ignition, an intermediate ignition pyrotechnic composition is pressed into the end of the element receiving the impulse, which has greater energy and greater sensitivity to the thermal impulse than the main composition of the candle. Known pyrochemical oxygen generators operate on thermocatalytic type chlorate candles containing sodium chlorate, barium peroxide, iron and binders, or catalytic type chlorate candles consisting of sodium chlorate and a catalyst, for example sodium or potassium oxide or peroxide. Known chemical generators release oxygen at a rate not less than 4 l/min, which is several times higher than the physiological need of a person. With known compositions, a lower rate of oxygen generation cannot be achieved. When reducing the diameter of the spark plug block, i.e. area of the burning front, which could lead to a decrease in speed, the candle loses its ability to burn. To maintain the functionality of a candle, a change in energy is required by increasing the proportion of fuel in the composition, which leads to an increase in the combustion rate and, accordingly, to an increase in the rate of oxygen release. A known generator contains pressed blocks of a solid oxygen source with transitional ignition elements, an initiating device, thermal insulation and a filter system in a metal housing with an outlet pipe for oxygen. The oxygen plug in this generator has a composition of sodium chlorate and sodium oxide and peroxide and consists of separate cylindrical blocks that are in contact with each other at their ends. Transitional ignition elements are pressed into the end of each block and are composed of aluminum and iron oxide. Some of the blocks have a curved shape, which makes it possible to lay them along a U-shaped, U-shaped line, in a spiral, etc. Due to the high rate of oxygen generation, the total weight of the oxygen candle required to ensure long-term operation of the generator increases. For example, to operate a prototype generator for 1 hour, a candle weighing about 1.2 kg is required. High speed generation also leads to the need to strengthen thermal insulation, which is also associated with an additional increase in the weight of the generator. Curved (angular) blocks are difficult to manufacture and have low mechanical strength: they easily break at the bend, which leads to the cessation of combustion at the break, i.e. reduce the reliability of long-term continuous operation of the generator. The purpose of the invention is to reduce the rate of oxygen generation and increase reliability during long-term operation of the generator. This is achieved by the fact that a pyrochemical oxygen generator containing pressed blocks of a solid oxygen source with transitional ignition elements, an initiating device, thermal insulation and a filter system, placed in a metal housing equipped with an outlet pipe for oxygen, has blocks of a solid oxygen source in the form of parallelepipeds, while a composition of sodium chlorate, calcium peroxide and magnesium is used as a solid source of oxygen; transitional ignition elements are prepared from a mixture of calcium peroxide with magnesium and pressed in the form of a tablet either into the end or into the side face of the block, and the blocks themselves are laid layer by layer and in a zigzag manner in each layer. Figure 1 shows a pyrochemical generator, general form. The generator has a metal housing 1, at the end of which there is an initiating device 2. On the upper edge of the housing there is a pipe 3 for oxygen outlet. Blocks 4 of the solid oxygen source are laid in layers and isolated from each other and from the walls of the housing by gaskets 5 made of porous ceramics. Metal meshes 6 are placed across the entire surface of the top layer of blocks and the top edge of the body, between which there is a multilayer filter 7. In FIG. Figure 2 shows a diagram of laying one layer of solid oxygen source blocks in the generator. Two types of blocks were used - long 4 with a pressed-in transition ignition pellet 9 at the end of the block and short 8 with a transition ignition pellet in the side wall. The generator is activated when the initiating device 2 is turned on, from which the ignition composition 10 ignites and the first block of the candle lights up. The combustion front moves continuously along the body of the candle, moving from block to block at the points of contact through transitional ignition tablets 9. As a result of the combustion of the candle, oxygen is released. The resulting oxygen flow passes through the pores of the ceramic 5, where it is partially cooled and enters the filter system. Passing through metal meshes and filters, it is additionally cooled and freed from unwanted impurities and smoke. Pure oxygen suitable for breathing comes out through pipe 3. The rate of oxygen generation, depending on the requirements, can be changed in the range from 0.7 to 3 l/min, changing the composition of the solid source of oxygen in the weight ratio NaClO 4 CaO 2 Mg 1 (0.20-0.24) (0.04- 0.07) and the composition of the ignition elements CaO 2 Mg in a weight ratio of 1 (0.1-0.2). The combustion of one layer of solid oxygen source blocks lasts 1 hour. If longer operation is necessary, the combustion is transferred using a short block 11 to the next layer located parallel to the first, etc. The total weight of the candle elements for one hour of burning is 300 g; total heat release is about 50 kcal/h. In the proposed generator, an oxygen candle in the form of parallelepiped elements simplifies their connection to each other and allows for dense and compact packaging. Rigid fastening and elimination of mobility of parallelepiped blocks ensures their safety during transportation and use as part of a breathing apparatus, and thus increases the reliability of long-term operation of the generator.

Claim

1. PYROCHEMICAL OXYGEN GENERATOR containing pressed blocks of a solid oxygen source with transitional ignition elements, an initiating device, thermal insulation and a filter system, placed in a metal housing equipped with an outlet pipe for oxygen, characterized in that the blocks of a solid oxygen source are made in the form of parallelepipeds, with In this case, a composition of sodium chlorate, calcium and magnesium peroxide, and transitional ignition elements - a mixture of calcium peroxide with magnesium - are used as a solid source of oxygen and are located at the end or side face of the block. 2. An oxygen generator according to claim 1, characterized in that blocks of a solid oxygen source are laid layer by layer and in a zigzag manner in each layer.

Use: to obtain oxygen in life support systems in emergency situations. The essence of the invention: the pyrotechnic composition includes 87 - 94 wt.% NaClO 3 and 6 - 13 wt.% Cu 2 S. O 2 output 231 - 274 l/kg, temperature in the combustion zone 520 - 580 o C. 1 table.

The invention relates to the field of obtaining gaseous oxygen from solid compositions that generate oxygen due to a self-sustaining thermocatalytic reaction occurring between the components of the composition in a narrow combustion region. Such compositions are called oxygen candles. The generated oxygen can be used in life support systems and in emergency situations of dispatch services. Known pyrotechnic sources of oxygen, the so-called oxygen or chlorate candles, contain three main components: oxygen carrier, fuel and catalyst. In chlorine candles, the oxygen carrier is sodium chlorate, the content of which is in the range of 80-93%. The fuel is iron metal powder with carbon dioxide. The catalyst function is performed by metal oxides and peroxides, for example MgFeO 4 . The oxygen output is in the range of 200-260 l/kg. The temperature in the combustion zone of chlorate candles containing metal as fuel exceeds 800 o C. The closest to the invention is the composition containing sodium chlorate as an oxygen carrier, 92% fuel, a magnesium alloy with silicon in a ratio of 1:1 (3 wt.), and in As a catalyst, a mixture of copper and nickel oxides in a ratio of 1:4. The oxygen yield from this composition is 265 5 l/kg. The temperature in the combustion zone is 850-900 o C. The disadvantage of the known composition is the high temperature in the combustion zone, which entails the need to complicate the design of the generator, the introduction of a special heat exchanger for cooling oxygen, the possibility of the generator housing catching fire from sparks of burning metal particles hitting it, the appearance of excess the amount of liquid phase (melt) near the combustion zone, which leads to deformation of the block and an increase in the amount of dust. The purpose of the invention is to reduce the temperature in the combustion zone of the composition while maintaining a high oxygen yield. This is achieved by the fact that the composition contains sodium chlorate as an oxygen carrier, and copper sulfite (Cu 2 S) as a fuel and catalyst. The components of the composition are taken in in the following respect, wt. sodium chlorate 87-94; copper sulfide 6-13. The possibility of using copper sulfide as a fuel and catalyst is based on a special mechanism of catalytic action. During the reaction, both components of copper sulfide are exothermically oxidized:

Сu 2 S + 2.5O 2 CuSO 4 + CuO + 202.8 kcal. This reaction supplies energy for the self-propagating process to occur. The specific enthalpy of combustion of Cu 2 S (1.27 kcal/g) is not much different from the specific enthalpy of combustion of iron (1.76 kcal/g). Most of the energy comes from the oxidation of sulfide sulfur to sulfate and only a small part from the oxidation of copper. Copper sulfide is more reactive than iron and magnesium metal powder, therefore the main exothermic reaction can occur quite quickly at a relatively low temperature of 500 o C. The low temperature in the combustion zone is also ensured by the fact that both copper sulfide and its oxidation product copper oxide are effective catalysts for the decomposition of sodium chlorate. According to DTA data, pure sodium chlorate, when heated at a rate of 10 o C/min, decomposes into NaCl and O 2 at 480-590 o C, in the presence of 6 wt. Cu 2 S at 260-360 o C, and in the presence of 12 wt. CuO at 390-520 o C. Cu 2 S powder has a higher dispersion< 0,01 мм и лучшей адгезией к хлорату натрия, по сравнению с металлическим Fe или Мg. Благодаря этому элементарный объем, приходящийся на долю каждой частицы горючего в случае значительно меньше, чем в случае частиц металла, что и обеспечивает меньшие температурные градиенты вблизи зоны горения и равномерность движения фронта горения. Дополнительные преимущества состава высокая равномерность горения и полное отсутствие искр, всегда наблюдаемые при горении составов с порошком металла, в качестве горючего. Выход кислорода в предлагаемом составе в зависимости от содержания Сu 2 S меняется от 230 до 274 л/кг. Температура горения лежит в пределах 520-580 о С, т. е. на 260-300 о С ниже, чем в известных составах. Скорость движения горячей зоны также зависит от содержания Сu 2 S и меняется от 0,23 до 0,5 мм/с при увеличении его от 6 до 13% Генерируемый кислород содержит небольшое количество диоксида серы около 0,2 мг/м 3 , что в 10 раз выше ПДК для медицинского кислорода. Используются технические реактивы без дополнительной очистки, производимые отечественной промышленностью. Для приготовления блоков смесь исходных компонентов перемешивают в шаровой мельнице в течение 30 мин. После этого прессуют блоки в стальной пресс-форме. Испытания прессованных блоков проводят в реакторе, снабженном воспламенительным устройством с электроспиралью. Объем выделившегося кислорода измеряют газосчетчиком ГСБ-400, температуру во фронте горения измеряют термопарой, помещенной в прессованный блок на глубину 5 мм. П р и м е р 1. Прессованный цилиндрический блок диаметром 30 мм и высотой 17,5 мм, содержащий 94 мас. NaClO 3 , 6 мас. сульфида меди, после инициирования спиралью равномерно горит со скоростью 0,23 мм/с с температурой в зоне горения 520 о С. Количество выделившегося кислорода 274 л/кг. В таблице представлены результаты испытаний состава по изобретению. Из них следует, что при уменьшении количества сульфида меди состав не горит. При увеличении количества сульфида меди относительно заявленных границ состав горит с очень высокой скоростью (выше 1 мм/с), с большим количеством пыли (100 мг/л). При такой высокой скорости горения возникает опасность взрыва состава. При занижении или завышении содержания хлората натрия или горючего-катализатора-сульфида меди состав теряет работоспособность. Таким образом, изобретение позволяет получить высокий выход кислорода 231-274 л/кг при сравнительно невысокой температуре в зоне горения 520-580 о С. Полученный кислород не содержит таких вредных примесей, как Сl 2 , углеродные соединения и минимальное количество SO 2 не более 0,55 кг/м 3 .

CLAIM

PYROTECHNIC COMPOSITION FOR PRODUCING OXYGEN, including sodium chlorate and a copper compound, characterized in that as a copper compound it contains copper sulfide with the following content of components, wt.%:

Oxygen plug is a device that, through a chemical reaction, produces oxygen suitable for consumption by living organisms. The technology was developed by a group of scientists from Russia and the Netherlands. Widely used by rescue services in many countries, also on airplanes, space stations like the ISS. The main advantages of this development are compactness and lightness.

Oxygen candle in space

Oxygen is a very important resource on board the ISS. But what happens if during an accident or accidental breakdown, life support systems, including the oxygen supply system, stop working? All living organisms on board simply will not be able to breathe and will die. Therefore, especially for such cases, astronauts have a fairly impressive supply of chemical oxygen generators; to put it simply, this is oxygen candles. How does the use of such a device in space work? general outline was shown in the film “Alive”.

Where does oxygen come from on an airplane?

Airplanes also use oxygen generators to chemical basis. If the board is depressurized or another breakdown occurs, an oxygen mask will fall out near each passenger. The mask will produce oxygen for 25 minutes, after which chemical reaction will stop.

How does it work?

Oxygen plug in space it consists of potassium perchlorate or chlorate. Most airplanes use barium peroxide or sodium chlorate. There is also an ignition generator and a filter for cooling and cleaning from other unnecessary elements.

Oxygen plug- this is a device that, using a chemical reaction, produces oxygen suitable for consumption by living organisms. The technology was developed by a group of scientists from Russia and the Netherlands. Widely used by rescue services in many countries, also on airplanes, and space stations such as the ISS. The main advantages of this development are compactness and lightness.

Oxygen candle in space

Oxygen is a very important resource on board the ISS. But what happens if during an accident or accidental breakdown, life support systems, including the oxygen supply system, stop working? All living organisms on board simply will not be able to breathe and will die. Therefore, especially for such cases, astronauts have a fairly impressive supply of chemical oxygen generators; to put it simply, this is oxygen candles. How such a device works and is used in space was shown in general terms in the film “Alive.”

Where does oxygen come from on an airplane?

Aircraft also use chemical-based oxygen generators. If the board is depressurized or another breakdown occurs, an oxygen mask will fall out near each passenger. The mask will produce oxygen for 25 minutes, after which the chemical reaction will stop.

How does it work?

The invention relates to oxygen generators for breathing and can be used in breathing apparatus for personal use, used in emergency situations, for example when extinguishing fires. In order to reduce the rate of oxygen generation and increase reliability during long-term operation, a pyrochemical oxygen generator containing pressed blocks of a solid oxygen source with transition ignition elements, an initiating device, thermal insulation and a filter system, placed in a metal case, equipped with an outlet pipe for oxygen, has solid source blocks oxygen in the form of parallelepipeds, while a composition of sodium chlorate, calcium peroxide and magnesium is used as a solid source of oxygen. Transitional ignition elements are prepared from a mixture of calcium peroxide with magnesium and are pressed in the form of tablets either into the end or into the side edge of the side, and the blocks themselves are laid in layers and in a zigzag manner in each layer. 1 z. p. f-ly, 2 ill.

The invention relates to oxygen generators for breathing and can be used in breathing apparatus for personal use, used in emergency situations, for example when extinguishing fires.

A pyrochemical oxygen generator is a device consisting of a housing, inside of which there is a composition capable of releasing oxygen through a self-propagating pyrochemical process: an oxygen candle, an ignition device for initiating combustion of the candle, a filter system for purifying the gas from foreign impurities and smoke, and thermal insulation. Through the outlet pipe, oxygen is supplied to the point of consumption through the pipeline.

In most known oxygen generators, the spark plug is made in the form of a cylindrical monoblock. The burning time of such a candle does not exceed 15 minutes. Longer operation of the generator is achieved by using several blocks (elements) laid so that their ends touch. When the combustion of one block ends, the thermal impulse initiates the combustion of the next element of the candle, and so on until it is completely used up. For more reliable ignition, an intermediate ignition pyrotechnic composition is pressed into the end of the element receiving the impulse, which has greater energy and greater sensitivity to the thermal impulse than the main composition of the candle.

Known pyrochemical oxygen generators operate on thermocatalytic type chlorate candles containing sodium chlorate, barium peroxide, iron and binders, or catalytic type chlorate candles consisting of sodium chlorate and a catalyst, for example sodium or potassium oxide or peroxide. Known chemical generators release oxygen at a rate not less than 4 l/min, which is several times higher than the physiological need of a person. With known compositions, a lower rate of oxygen generation cannot be achieved. When reducing the diameter of the spark plug block, i.e. area of the burning front, which could lead to a decrease in speed, the candle loses its ability to burn. To maintain the functionality of a candle, a change in energy is required by increasing the proportion of fuel in the composition, which leads to an increase in the combustion rate and, accordingly, to an increase in the rate of oxygen release.

A known generator contains pressed blocks of a solid oxygen source with transitional ignition elements, an initiating device, thermal insulation and a filter system in a metal housing with an outlet pipe for oxygen. The oxygen plug in this generator has a composition of sodium chlorate and sodium oxide and peroxide and consists of separate cylindrical blocks that are in contact with each other at their ends. Transitional ignition elements are pressed into the end of each block and are composed of aluminum and iron oxide. Some of the blocks have a curved shape, which makes it possible to lay them along a U-shaped, U-shaped line, in a spiral, etc.

Due to the high rate of oxygen generation, the total weight of the oxygen candle required to ensure long-term operation of the generator increases. For example, to operate a prototype generator for 1 hour, a candle weighing about 1.2 kg is required. The high generation rate also leads to the need to enhance thermal insulation, which is also associated with an additional increase in the weight of the generator.

Curved (angular) blocks are difficult to manufacture and have low mechanical strength: they easily break at the bend, which leads to the cessation of combustion at the break, i.e. reduce the reliability of long-term continuous operation of the generator.

The purpose of the invention is to reduce the rate of oxygen generation and increase reliability during long-term operation of the generator.

This is achieved by the fact that a pyrochemical oxygen generator containing pressed blocks of a solid oxygen source with transitional ignition elements, an initiating device, thermal insulation and a filter system, placed in a metal housing equipped with an outlet pipe for oxygen, has blocks of a solid oxygen source in the form of parallelepipeds, while a composition of sodium chlorate, calcium peroxide and magnesium is used as a solid source of oxygen; transitional ignition elements are prepared from a mixture of calcium peroxide with magnesium and pressed in the form of a tablet either into the end or into the side face of the block, and the blocks themselves are laid layer by layer and in a zigzag manner in each layer.

Figure 1 shows a pyrochemical generator, general view. The generator has a metal housing 1, at the end of which there is an initiating device 2. On the upper edge of the housing there is a pipe 3 for oxygen outlet. Blocks 4 of the solid oxygen source are laid in layers and isolated from each other and from the walls of the housing by gaskets 5 made of porous ceramics. Metal meshes 6 are placed across the entire surface of the top layer of blocks and the top edge of the body, between which there is a multilayer filter 7.

In fig. Figure 2 shows a diagram of laying one layer of solid oxygen source blocks in the generator. Two types of blocks were used - long 4 with a pressed-in transition ignition pellet 9 at the end of the block and short 8 with a transition ignition pellet in the side wall.

The generator is activated when the initiating device 2 is turned on, from which the ignition composition 10 ignites and the first block of the candle lights up. The combustion front moves continuously along the body of the candle, moving from block to block at the points of contact through transitional ignition tablets 9. As a result of the combustion of the candle, oxygen is released. The resulting oxygen flow passes through the pores of the ceramic 5, where it is partially cooled and enters the filter system. Passing through metal meshes and filters, it is additionally cooled and freed from unwanted impurities and smoke. Pure oxygen suitable for breathing comes out through pipe 3.

The rate of oxygen generation, depending on the requirements, can be changed in the range from 0.7 to 3 l/min, changing the composition of the solid source of oxygen in the weight ratio NaClO 4 CaO 2 Mg 1 (0.20-0.24) (0.04- 0.07) and the composition of the ignition elements CaO 2 Mg in a weight ratio of 1 (0.1-0.2). The combustion of one layer of solid oxygen source blocks lasts 1 hour. If longer operation is necessary, the combustion is transferred using a short block 11 to the next layer located parallel to the first, etc. The total weight of the candle elements for one hour of burning is 300 g; total heat release is about 50 kcal/h.

In the proposed generator, an oxygen candle in the form of parallelepiped elements simplifies their connection to each other and allows for dense and compact packaging. Rigid fastening and elimination of mobility of parallelepiped blocks ensures their safety during transportation and use as part of a breathing apparatus, and thus increases the reliability of long-term operation of the generator.

2. An oxygen generator according to claim 1, characterized in that blocks of a solid oxygen source are laid layer by layer and in a zigzag manner in each layer.

OXYGEN(Latin Oxygenium, from Greek oxys sour and gennao - I give birth) Oh, chemical. element VI gr. periodic systems, at. n. 8, at. m. 15.9994. Nature K. consists of three stable isotopes: 16 O (99.759%), 17 O (0.037%) and 18 O (0.204%]. Configuration of the outer electron shell of the atom 2s 2 2p; ionization energies O° : O + : O 2+ are equal respectively. 13.61819, 35.118 eV; Pauling electronegativity 3.5 (most electronegative element after F); electron affinity 1.467 eV; covalent radius 0.066 nm. The K molecule is diatomic. There is also an allotropic modification of K. ozone O 3. The interatomic distance in the O 2 molecule is 0.12074 nm; ionization energy of O 2 12.075 eV; electron affinity 0.44 eV; dissociation energy 493.57 kJ/mol, dissociation constant K r=p O 2 /p O2 is 1.662. 10 -1 at 1500 K, 1.264. 10 -2 at 3000 K, 48.37 at 5000 K; ionic radius of O 2 (coordination numbers are indicated in parentheses) 0.121 nm (2), 0.124 nm (4), 0.126 nm (6) and 0.128 nm (8). In the ground state (triplet) there are two valence electrons of the O 2 molecule located in antibonding orbitals p X and p y, are not paired, due to which K. is paramagnetic (unity, paramagnetic gas, consisting of homonuclear diatomic molecules); molar mag. gas susceptibility 3.4400. 10 (293 K), varies inversely with abs. t-re (Curie's law). There are two long-lived excited states of O 2 - singlet 1 D g (excitation energy 94.1 kJ/mol, lifetime 45 min) and singlet (excitation energy 156.8 kJ/mol). K.-naib. a common element on Earth. The atmosphere contains 23.10% by mass (20.95% by volume) free. K., in the hydrosphere and lithosphere - respectively. 85.82 and 47% by weight of bound potassium. More than 1,400 minerals are known, which include potassium. The loss of potassium in the atmosphere as a result of oxidation, including combustion, decay and respiration, is compensated by the release of potassium by plants during photosynthesis. K. is part of all substances from which living organisms are built; the human body contains approx. 65%. Properties. K.-colorless odorless and tasteless gas. T. kip. 90.188 K, triple point temperature 54.361 K; dense at 273 K and normal pressure 1.42897 g/l, density. (in kg/m3) at 300 K: 6.43 (0.5 MPa), 12.91 (1 MPa), 52.51 (4 MPa); t critical 154.581 K, R Crete 5.043 MPa, d crit 436.2 kg/m 3 ; C 0 p 29.4 J/(mol. TO); D H 0 isp 6.8 kJ/mol (90.1 K); S O 299 205.0 JDmol. . K) at 273 K; h 205.2 3 10 -7 Pa. s (298 K). Liquid K. is colored blue; dense 1.14 g/cm 3 (90.188 K); C O p 54.40 J/(mol. TO); thermal conductivity 0.147 Wdm. K) (90 K, 0.1 MPa); h 1,890. 10 -2 Pa. With; g 13.2. 10 -5 N/m (90 K), level temperature dependence g = -38.46. 10 -3 (1 - T/154.576) 11/9 N/m; n D 1,2149 ( l =546.1 nm; 100 K); non-conductive; molar mag. susceptibility 7.699. 10 -3 (90.1 K). Solid K. exists in several. crystalline modifications. Below 23.89 K, the a-form with body-centered is stable. rum-beach, grid (at 21 K and 0.1 MPa A= 0.55 nm, b = 0.382 nm, s=0.344 nm, density. 1.46 g/cm 3), at 23.89-43.8 K- b - form with hexagen, crystalline. grating (at 28 K and 0.1 MPa A= 0.3307 nm, s = 1.1254 nm), above 43.8 K there is g - cubic shape lattice ( A= 0.683 nm); D H° of polymorphic transitions g : b 744 J/mol (43.818 K), b:a 93.8 J/mol (23.878 K); triple point b-g- gaseous K.: temperature 283 K, pressure 5.0 GPa; D H O mp 443 J/mol; Level of temperature dependence of density d= 1.5154-0.004220T g/cm 3 (44 54 K), a-, b- and g- O 2 light blue crystals. Modification p is antiferromagnetic, a and g paramagnetic, their magnet. susceptibility resp. 1,760. 10 -3 (23.7 K) and 1.0200. 10 -5 (54.3 K). At 298 K and an increase in pressure to 5.9 GPa, K crystallizes, forming pink-colored hexagen. b -form ( a = 0.2849 nm, c = 1.0232 nm), and when the pressure increases to 9 GPa, an orange diamond shape. e -form (at 9.6 GPa A=0.42151 nm, b= 0.29567 nm, With=0.66897 nm, density 2.548 g/cm 3). R-rate of K. at atm. pressure and 293 K (in cm 3 / cm 3): in water 0.031, ethanol 0.2201, methanol 0.2557, acetone 0.2313; pH value in water at 373 K 0.017 cm 3 /cm 3; pH value at 274 K (in % by volume): in perfluorobutyltetrahydrofuran 48.5, perfluorodecalin 45.0, perfluoro-l-methyldecalin 42.3. Good solid absorbents for K are platinum black and active charcoal. Noble metals in melt. state absorb means. number of K., e.g. at 960 °C one volume of silver absorbs ~22 volumes of K., which at when cooled, it is almost completely released. Many people have the ability to absorb K. solid metals and oxides, and nonstoichiometric ones are formed. connections. K. has a high chemical activity, forming a compound. with all elements except He, Ne and Ar. Atom K. in chemistry. conn. usually gains electrons and is negative. effective charge. Compounds in which electrons are drawn away from the K atom are extremely rare (for example, OF 2). With simple substances, except Au, Pt, Xe and Kr, K reacts directly under normal conditions or when heated, as well as in the presence. catalysts. Reactions with halogens are carried out under the influence of electricity. discharge or UV radiation. In areas with all simple substances except F 2, K is an oxidizing agent. Mol. K. forms three different. ionic forms, each of which gives rise to a class of compounds: O - 2 - superoxides, O 2 2- - peroxides (see Inorganic peroxide compounds, Organic peroxide compounds), O + 2 - dioxygenyl compounds. Ozone forms ozonides, in which the ionic form is K-O - 3. The O2 molecule attaches as a weak ligand to certain complexes of Fe, Co, Mn, Cu. Among these connections. Hemoglobin is important, as it transports blood in the body of warm-blooded animals. R-tions with K., accompanied by an intense release of energy, are called. burning. Interactions play a big role. K. with metals present. moisture-atm. metal corrosion, and breath living organisms and decay. As a result of rotting, complex org. The substances of dead animals and plants turn into simpler ones and, ultimately, into CO 2 and water. K reacts with hydrogen to form water and release a large amount of heat (286 kJ per mole of H2). At room temperature, the flow is extremely slow, in the presence. catalysts - relatively quickly already at 80-100 ° C (this solution is used to purify H 2 and inert gases from O 2 impurities). Above 550 °C, the reaction of H 2 with O 2 is accompanied by an explosion. From elements of I gr. max. react easily with K. Rb and Cs, which spontaneously ignite in air, K, Na and Li react with K. more slowly, the reaction accelerates in the presence. water vapor. When burning alkali metals(except for Li) in the K atmosphere, peroxides M 2 O 2 and superoxides MO 2 are formed. K reacts relatively easily with elements of subgroup IIa, for example, Ba can ignite in air at 20-25 ° C, Mg and Be ignite above 500 ° C; The products of the solution in these cases are oxides and peroxides. With elements of subgroup IIb K. interaction. with great difficulty, the solution of K. with Zn, Cd and Hg occurs only at higher temperatures (rocks are known in which Hg is contained in elemental form). On the surfaces of Zn and Cd, strong films of their oxides are formed, protecting the metals from further oxidation. Elements III gr. react with K. only when heated, forming oxides. Compact metals Ti, Zr, and Hf are resistant to the action of carbon. It reacts with carbon to form CO 2 and release heat (394 kJ/mol); with amorphous carbon, the reaction occurs with slight heating, with diamond and graphite - above 700 ° C. K. reacts with nitrogen only above 1200°C with the formation of NO, which is then easily oxidized by K. to NO 2 already at room temperature. White phosphorus is prone to spontaneous combustion in air at room temperature. Elements VI gr. S, Se, and Te react with potassium at a noticeable rate upon moderate heating. Noticeable oxidation of W and Mo is observed above 400 °C, Cr - at a much higher temperature. K. vigorously oxidizes org. connections. The combustion of liquid fuels and combustible gas occurs as a result of the reaction of carbon with hydrocarbons.
Receipt. In industry K. get air separation, Ch. arr. by low-temperature rectification method. It is also produced along with H 2 during industrial production. electrolysis of water. They produce gaseous technol. K. (92-98% O 2), tech. (1st grade 99.7% O 2 , 2nd grade 99.5% and 3rd grade 99.2%) and liquid (not less than 99.7% O 2). K. is also produced for medicinal purposes (“medical oxygen"containing 99.5% O 2). For breathing in confined spaces (submarines, spacecraft, etc.) use solid sources of K., the action of which is based on self-propagating exo-thermal. r-tion between the carrier K. (chlorate or perchlorate) and fuel. For example, a mixture of NaClO 3 (80%), Fe powder (10%), BaO 2 (4%) and glass fiber (6%) is pressed into cylinders; after ignition like this oxygen the candle burns at a speed of 0.15-0.2 mm/s, releasing pure, breathable carbon in an amount of 240 l/kg (see. Pyrotechnic gas sources). In the laboratory, K. is obtained by decomposition when heated. oxides (e.g. HgO) or oxygen-containing salts (for example, KClO 3, KMnO 4), as well as electrolysis of an aqueous solution of NaOH. However, most often they use industrial. K., supplied in pressure cylinders.
Definition. The concentration of K. in gases is determined using hand-held gas analyzers, for example. volumetric a method for changing the known volume of the analyzed sample after absorbing O 2 from it in solutions - copper-ammonia, pyrogallol, NaHSO 3, etc. For the continuous determination of K in gases, automatic thermomagnetic gas analyzers based on high magnetic susceptibility of K. To determine small concentrations of K. in inert gases or hydrogen (less than 1%) use automatic. thermochemical, electrochemical, galvanic and other gas analyzers. For the same purpose, colorimetric is used. method (using the Mugdan device) based on the oxidation of colorless. ammonia complex Cu(I) into a brightly colored compound. Cu(II). K., dissolved in water, is also determined colorimetrically, for example. by the formation of a red color during the oxidation of reduced indigo carmine. In org. conn. K is determined in the form of CO or CO 2 after high-temperature pyrolysis of the analyzed substance in a flow of inert gas. To determine the concentration of potassium in steel and alloys, electrochemical chemicals are used. sensors with solid electrolyte (stabilized ZrO 2). see also Gas analysis, Gas analyzers.
Application. K. is used as an oxidizing agent: in metallurgy - in the smelting of cast iron and steel (in blast furnace, oxygen converter and open-hearth production), in the processes of shaft, flash and converter smelting of non-ferrous metals; in rolling production; during fire stripping of metals; in foundry production; for thermite welding and cutting of metals; in chemistry and petrochemical industry for the production of HNO 3, H 2 SO 4, methanol, acetylene; formaldehyde, oxides, peroxides, etc. K. is used for medicinal purposes in medicine, as well as in oxygen-breathing. apparatus (in spacecraft, on submarines, during high-altitude flights, underwater and rescue operations). Liquid carbon oxidizer for rocket fuels; It is also used in blasting operations, as a coolant in the laboratory. practice. K. production in the USA is 10.75 billion m 3 (1985); in metallurgy, 55% of the produced carbon is consumed; in chemical industry. forgive - 20%. K. is non-toxic and non-flammable, but supports combustion. When mixed with liquid carbon, all hydrocarbons are explosive, incl. oils, CS 2. max. dangerous are poorly soluble flammable impurities that pass into liquid K. into solid state(e.g. acetylene, propylene, CS 2). Maximum permissible content in liquid K: acetylene 0.04 cm 3 /l, CS 2 0.04 cm 3 /l, oil 0.4 mg/l. Gaseous K. is stored and transported in steel cylinders of small (0.4-12 l) and medium (20-50 l) capacity at a pressure of 15 and 20 MPa, as well as in large capacity cylinders (80-1000 l at 32 and 40 MPa ), liquid K. in Dewar vessels or in special. tanks. For transportation of liquid and gaseous liquids, special equipment is also used. pipelines. Oxygen the cylinders are painted blue and have the inscription in black letters " oxygen" . For the first time, K. in its pure form was obtained by K. Scheele in 1771. Independently of him, K. was obtained by J. Priestley in 1774. In 1775, A. Lavoisier established that K. is a component of air, and is contained in the plural. wow. Lit.. Glizmayenko D.L., Receipt oxygen, 5th ed., M., 1972; Razumovsky S. D., Oxygen-elemental forms and properties, M., 1979; Thermodynamic properties oxygen, M., 1981. Ya. D. Zelvensky.

The invention relates to the field of obtaining gaseous oxygen from solid compositions that generate oxygen due to a self-sustaining thermocatalytic reaction occurring between the components of the composition in a narrow combustion region. Such compositions are called oxygen candles. The generated oxygen can be used in life support systems and in emergency situations of dispatch services. Known pyrotechnic sources of oxygen, the so-called oxygen or chlorate candles, contain three main components: oxygen carrier, fuel and catalyst. In chlorine candles, the oxygen carrier is sodium chlorate, the content of which is in the range of 80-93%. The fuel is iron metal powder with carbon dioxide. The catalyst function is performed by metal oxides and peroxides, for example MgFeO 4 . The oxygen output is in the range of 200-260 l/kg. The temperature in the combustion zone of chlorate candles containing metal as fuel exceeds 800 o C. The closest to the invention is the composition containing sodium chlorate as an oxygen carrier, 92% fuel, a magnesium alloy with silicon in a ratio of 1:1 (3 wt.), and in As a catalyst, a mixture of copper and nickel oxides in a ratio of 1:4. The oxygen yield from this composition is 265 5 l/kg. The temperature in the combustion zone is 850-900 o C. The disadvantage of the known composition is the high temperature in the combustion zone, which entails the need to complicate the design of the generator, the introduction of a special heat exchanger for cooling oxygen, the possibility of the generator housing catching fire from sparks of burning metal particles hitting it, the appearance of excess the amount of liquid phase (melt) near the combustion zone, which leads to deformation of the block and an increase in the amount of dust. The purpose of the invention is to reduce the temperature in the combustion zone of the composition while maintaining a high oxygen yield. This is achieved by the fact that the composition contains sodium chlorate as an oxygen carrier, and copper sulfite (Cu 2 S) as a fuel and catalyst. The components of the composition are taken in the following ratio, wt. sodium chlorate 87-94; copper sulfide 6-13. The possibility of using copper sulfide as a fuel and catalyst is based on a special mechanism of catalytic action. During the reaction, both components of copper sulfide are exothermically oxidized:

CLAIM

OXYGEN IS CONTAINED IN THE AIR. NATURE OF THE ATMOSPHERE. ITS PROPERTIES. OTHER CANDLE COMBUSTION PRODUCTS. CARBONIC ACID, ITS PROPERTIES

We have already seen that hydrogen and oxygen can be obtained from water obtained by burning a candle. You know that hydrogen comes from a candle, and oxygen, you believe, comes from the air. But in this case, you have the right to ask me: “Why is it that air and oxygen do not burn a candle equally well?” If you have a fresh memory of what happened when I covered the cinder with a jar of oxygen, you will remember that here the combustion proceeded completely differently than in the air. So what's the deal? This is a very important question, and I will do my best to help you understand it; it is directly related to the question of the nature of the atmosphere and is therefore extremely important for us.

We have several ways of recognizing oxygen, in addition to simply burning certain substances in it. You have seen how a candle burns in oxygen and in air; you saw how phosphorus burns in air and in oxygen; you saw how iron burns in oxygen. But, besides these methods of recognizing oxygen, there are others, and I will analyze some of them to expand your experience and your knowledge. Here, for example, is a vessel with oxygen. I will prove to you the presence of this gas. I'll take a smoldering splinter and put it in oxygen. You already know from the last conversation what will happen: a smoldering splinter dropped into a jar will show you whether there is oxygen in it or not. Eat! We proved this by burning.

Here is another way to recognize oxygen, very interesting and useful. Here I have two jars, each filled with gas. They are separated by a plate so that these gases do not mix. I remove the plate, and the mixing of gases begins: each gas seems to creep into the jar where the other is located. “So what’s going on here?” you ask. “They together do not produce the kind of combustion that we observed with a candle.” But look how the presence of oxygen can be recognized by its combination with this second substance.

What a magnificently colored gas it turned out to be. It signals to me the presence of oxygen. The same experiment can be done by mixing this test gas with ordinary air. Here is a jar with air - the kind in which a candle would burn - and here is a jar with this test gas. I let them mix over water, and this is the result: the contents of the test jar flow into the jar with air, and you see exactly the same reaction happening. This proves that there is oxygen in the air, i.e. the same substance that we have already extracted from the water obtained by burning a candle.

But still, why doesn’t a candle burn as well in air as in oxygen? We'll get to that now. Here I have two jars; they are filled with gas to the same level, and they look the same. To tell the truth, I don’t even know now which of these cans contains oxygen and which contains air, although I know that they were filled with these very gases in advance. But we have a test gas, and I will now find out whether there is any difference between the contents of both jars in the ability to cause this gas to turn red. I let the test gas into one of the cans. Watch what happens. As you can see, there is redness, which means there is oxygen here. Let's now try the second jar. As you can see, the redness is not as pronounced as in the first jar.

Then a curious thing happens: if the mixture of two gases in the second jar is thoroughly shaken with water, the red gas is absorbed; if you let in another portion of the test gas and shake the jar again, the absorption of the red gas will repeat; and this can be continued as long as oxygen remains, without which this phenomenon is impossible. If I let air in, things won't change; but as soon as I introduce water, the red gas disappears; and I can continue in this way to let in more and more test gas until I have something left in the jar that will no longer be colored by the addition of the substance that colored air and oxygen. What's the matter? You understand that in the air, besides oxygen, there is something else, and it remains in the remainder. Now I will let a little more air into the jar, and if it turns red, you will know that there was still some amount of coloring gas left there and that, therefore, it is not its lack that explains the fact that not all of the air was used up.

This will help you understand what I am about to say. You saw that when I burned the phosphorus in the jar, and the resulting smoke from the phosphorus and oxygen settled, a fair amount of gas remained unused, just as our test gas left something unaffected. And indeed, after the reaction, this gas remained, which does not change either from phosphorus or from the coloring gas. This gas is not oxygen, but, nevertheless, it is an integral part of the atmosphere.

This is one way of dividing air into the two substances of which it consists, that is, into oxygen, which burns our candles, phosphorus and everything else, and into this other substance - nitrogen, in which they do not burn. There is much more of this second component in the air than oxygen.

This gas turns out to be a very interesting substance if you study it, but you might say that it is not interesting at all. In some respects this is true: it does not exhibit any brilliant combustion effects. If you test it with a lit splinter, as I tested oxygen and hydrogen, then it will neither burn like hydrogen itself, nor cause the splinter to burn, like oxygen. No matter how I test it, I cannot achieve either one or the other from it: it neither lights up nor allows a splinter to burn - it extinguishes the combustion of any substance. Under normal conditions, nothing can burn in it. It has neither smell nor taste; it is neither acid nor alkali; in relation to all our external feelings he shows complete indifference. And you might say: “This is nothing, it does not deserve the attention of chemistry; why does it exist in the air?”

And this is where the ability to draw conclusions from experience comes in handy. Suppose that instead of nitrogen or a mixture of nitrogen and oxygen, our atmosphere consisted of pure oxygen, what would become of us? You know very well that a piece of iron, lit in a jar of oxygen, burns to ashes. When you see a burning fireplace, imagine what would happen to its grate if the entire atmosphere consisted of only oxygen: the cast-iron grate would burn much hotter than the coal we use to heat the fireplace. A fire in the furnace of a steam locomotive would be the same as a fire in a fuel warehouse if the atmosphere consisted of oxygen.

Nitrogen dilutes oxygen, moderates its effects and makes it useful to us. In addition, nitrogen takes with it all the fumes and gases that, as you saw, arise when a candle burns, disperses them throughout the atmosphere and transfers them to where they are needed to support the life of plants, and thereby humans. Thus, nitrogen performs to the highest degree important work, although you, having familiarized yourself with it, say: “Well, this is a completely worthless thing.”

In its normal state, nitrogen is an inactive element: no influence, except a very strong electrical discharge, and even then only to a very weak degree, can cause nitrogen to directly combine with another element of the atmosphere or with other surrounding substances. This substance is completely indifferent, that is, in other words, indifferent, and therefore safe.

But before I lead you to this conclusion, I must first tell you something about the atmosphere itself. Here is a table showing percentage composition atmospheric air:

by volume by mass

Oxygen. . . . 20 22.3

Nitrogen. . . . . 80 77.7

__________________________

It correctly reflects the relative amounts of oxygen and nitrogen in the atmosphere. From this we see that in five pints of air there is only one pint of oxygen to four pints of nitrogen; in other words, nitrogen makes up 4/5 of atmospheric air by volume. All this amount of nitrogen is used to dilute oxygen and soften its effect; as a result, the candle is properly supplied with fuel and our lungs can breathe air without harm to health. After all, it is no less important for us to receive oxygen for breathing in the proper form than to have the appropriate composition of the atmosphere for burning coal in a fireplace or a candle.

Now I will tell you the masses of these gases. A pint of nitrogen has a mass of 10 4/10 grains, and a cubic foot has 1 1/6 ounces. This is the mass of nitrogen. Oxygen is heavier: a pint weighs 11 9/10 grains, and a cubic foot weighs 1 1/5 ounces.

You have already asked me the question several times: “How is the mass of gases determined?”, and I am very glad that this question interested you. Now I will show you, this matter is very simple and easy. Here are the scales, and here is a copper bottle, carefully turned on a lathe and, for all its strength, having the smallest possible mass. It is completely airtight and equipped with a tap. Now the tap is open, and therefore the bottle is filled with air. These scales are very precise, and the bottle in its present state is balanced on them by weights on another cup. And here is the pump with which we can pump air into this bottle.

Rice. 25.

Now we will pump a known amount of air into it, the volume of which will be measured by the capacity of the pump. (Twenty such volumes are pumped.) Now we will close the tap and put the bottle back on the scale. See how the scales have dropped: the bottle has become much heavier than before. The capacity of the bottle has not changed, which means that the air in the same volume has become heavier. Whereby? Thanks to the air that we pumped into it. in addition to the available air.

Now we will release the air into that jar and give it the opportunity to return to its previous state. All I need to do for this is to tightly connect the copper bottle to the jar and open the taps - and you see, we have collected the entire volume of air that I just pumped into the bottle with twenty strokes of the pump. To make sure that no error occurred during this experiment, we will again put the bottle on the scales. If it is now again balanced by the original load, we can be absolutely sure that we have done the experiment correctly. Yes, she balanced out. This is how we can find out the mass of those additional portions of air that we pumped into it. Thus it can be established that a cubic foot of air has a mass of 1 1/5 ounces.

Rice. 26.

But this modest experience will in no way be able to bring to your consciousness the full essence of the result obtained. It's amazing how much the numbers increase as we move to larger volumes. This is the amount of air (cubic foot) that has a mass of 1 1/5 ounces. What do you think, what is the mass of air in that box at the top (I specially ordered it for these calculations)? The air in it has a mass of a whole pound. I calculated the mass of air in this room, but you would hardly guess this figure: it is more than a ton. This is how quickly masses increase, and this is how important the presence of the atmosphere and the oxygen and nitrogen it contains, as well as the work it does, moving objects from place to place and carrying away harmful fumes.

Having given you these few examples relating to the weight of air, I will now proceed to show some of the consequences of this fact. You definitely need to get to know them, otherwise much will remain unclear to you. Do you remember such an experience? Have you ever seen him? A pump is taken for it, somewhat similar to the one with which I just pumped air into the copper bottle.

Rice. 27.

It needs to be positioned so that I can place my palm over its opening. In the air, my hand moves so easily, as if it feels no resistance. No matter how I move, I almost never manage to achieve such a speed that I feel a lot of air resistance to this movement). But when I put my hand here (on the air pump cylinder, from which the air is then pumped out), you see what happens. Why does my palm stick to this place so tightly that the entire pump moves behind it? Look! Why can I barely free my hand? What's the matter? It's about the weight of the air - the air that is above me.

Here is another experience that I think will help you understand this issue even better. The top of this jar will be covered with a bull's bladder, and when the air is pumped out of it, you will see, in a slightly modified form, the same effect as in the previous experiment. Now the top is completely flat, but if I make even a very slight movement with the pump, and look how the bubble drops, how it bends inward. You will now see how the bubble will be drawn more and more into the jar until, finally, it is completely pressed in and broken through by the force of the atmosphere pressing on it. (The bubble burst with a loud bang.) So, this happened entirely from the force with which the air pressed on the bubble, and it will not be difficult for you to understand how things stand here.

Rice. 28.

Look at this column of five cubes: the particles piled up in the atmosphere are arranged one above the other in the same way. It is quite clear to you that the four upper cubes rest on the fifth, lower one, and that if I take it out, all the others will go down. The situation is the same in the atmosphere: the upper layers of air are supported by the lower ones, and when the air is pumped out from under them, changes occur that you observed when my palm lay on the pump cylinder and in the experiment with the bull bubble, and now you will see even better.

I tied this jar with rubber. membrane. Now I will pump the air out of it, and you watch the rubber that separates the air below from the air above. You will see how the atmospheric pressure will develop as the air is pumped out of the can. See how the rubber is retracted - after all, I can even put my hand into the jar - and all this is only as a result of the powerful, colossal influence of the air above us. How clearly this interesting fact appears here!

After the end of today's lecture, you will be able to measure your strength by trying to separate this device. It consists of two hollow copper hemispheres, tightly fitted to each other and equipped with a tube with a tap for pumping out air. As long as there is air inside, the hemispheres are easily separated; however, you will be convinced that when we pump air through this tube with a tap and you pull them - one in one direction, the other in the other - none of you will be able to separate the hemispheres. Each square inch of cross-sectional area of this vessel, when the air is pumped out, has to support about fifteen pounds. Then I will give you the opportunity to test your strength - try to overcome this air pressure.

Here's another interesting little thing - a suction cup, a game for boys, but only improved for scientific purposes. After all, you, young people, have every right to use toys for the purposes of science, especially since in modern times they have begun to make fun out of science. Here is a suction cup, only it is not leather, but rubber. I plop it on the surface of the table, and you immediately see that it is firmly stuck to it. Why is she holding on like that? It can be moved, it easily slides from place to place, but no matter how hard you try to lift it, it will probably pull the table with it rather than tear itself away from it. You can only remove it from the table when you move it to the very edge to let air under it. Only the air pressure above it presses it to the table surface. Here is another suction cup - press them together and you will see how firmly they stick. We can use them, so to speak, for their intended purpose, that is, stick them to windows and walls, where they will last for several hours and will be useful for hanging some objects on them.

However, I need to show you not only toys, but also experiments that you can repeat at home. Visually prove the existence atmospheric pressure can be such an elegant experience. Here's a glass of water. What if I asked you to manage to turn it upside down without any water spilling? And not because you put your hand up, but solely due to atmospheric pressure.

Take a glass filled to the brim or half with water, and cover it with some cardboard; tip it over and see what happens to the cardboard and the water. Air will not be able to penetrate the glass, since water will not let it in due to capillary attraction to the edges of the glass.

I think that all this will give you the correct idea that air is not emptiness, but something material. When you learn from me that that box over there holds a pound of air, and this room holds more than a ton, you will believe that air is not just emptiness.

Let's do one more experiment to convince you that air can really offer resistance. You know what a magnificent blowgun can be easily made from a goose feather, or a tube, or something like that. Taking a slice of apple or potato, you need to cut out a small piece of it to the size of the tube - like this - and push it through to the very end, like a piston. By inserting the second plug, we completely isolate the air in the tube. And now it turns out that pushing the second plug close to the first is completely impossible. It is possible to compress the air to some extent, but if we continue to press on the second plug, then it will not yet have time to approach the first one before the compressed air will push it out of the tube, and moreover, with a force reminiscent of the action of gunpowder - after all, it is also associated with that reason which we observed here.

The other day I saw an experiment that I really liked because it can be used in our classes. (Before starting it, I should be silent for about five minutes, since the success of this experiment depends on my lungs.) I hope that by the power of my breathing, that is, by the proper use of air, I will be able to lift an egg standing in one glass , and throw it to another. I can’t vouch for success: after all, I’ve been talking for too long. (The lecturer successfully performs the experiment.) The air that I blow out passes between the egg and the wall of the glass; a pressure of air arises under the egg, which is able to lift heavy object: after all, for air, an egg is a really heavy object. In any case, if you want to do this experiment yourself, it’s better to take a hard-boiled egg, and then you can, without risk, try to carefully move it from one glass to another with the power of your breath.

Although we have spent quite a long time on the question of the mass of air, I would like to mention one more property of it. In the blowgun experiment you will see that before the first potato plug came out, I managed to push the second one in half an inch or more. And this depends on a wonderful property of air - its elasticity. You can get to know her through the following experience.

Let us take a shell that is impenetrable to air, but capable of stretching and contracting, and thereby giving us the opportunity to judge the elasticity of the air contained in it. Now there is not much air in it, and we will tightly tie the neck so that it cannot communicate with the surrounding air. Until now, we have done everything in such a way as to show the atmospheric pressure on the surface of objects, but now, on the contrary, we will get rid of atmospheric pressure. To do this, we will place our shell under the bell of the air pump, from under which we will pump out the air. Before your eyes, this shell will straighten out, inflate like a balloon, and will become larger and larger until it fills the entire bell. But as soon as I again open access to the outside air into the bell, our ball will immediately fall. Here is a visual proof of this amazing property of air - its elasticity, that is, its extremely high ability to compress and expand. This property is very significant and largely determines the role of air in nature.

Let us now move on to another very important section of our topic. Remember that when we worked on burning a candle, we found out that various combustion products are formed. These products include soot, water and something else that has not yet been explored by us. We collected the water and allowed other substances to disperse into the air. Let's now explore some of these products.

Rice. 29.

In particular, the following experience will help us in this matter. Here we will place a burning candle and cover it with a glass cap with an outlet pipe at the top... The candle will continue to burn, since air passes freely below and above. First of all, you see that the cap is made wet; you already know what it’s all about: it’s water produced by burning a candle from the action of air on hydrogen. But, besides this, something is coming out of the outlet pipe at the top; it is not water vapor, it is not water, this substance does not condense, and besides, it has special properties. You see that the stream coming out of the tube almost manages to extinguish the light that I bring to it; if I hold a lit splinter directly in the emerging stream, it will go out completely. “It’s in the order of things,” you say; Obviously, this does not surprise you because nitrogen does not support combustion and must extinguish the flame, since the candle does not burn in it. But is there nothing here except nitrogen?

Here I will have to get ahead of myself: based on the knowledge I have, I will try to equip you with scientific methods for studying such gases and clarifying these issues in general.

Let's take an empty jar and hold it over the outlet tube so that the products of candle combustion collect in it. It will not be difficult for us to discover that this jar contains not just air, but a gas that also has other properties. To do this, I take a little quicklime, pour it in and stir it well. Having put a circle of filter paper into the funnel, I filter this mixture through it, and clean, transparent water flows into the flask placed under it. I have as much of this water as I want in another vessel, but to be convincing, I prefer to use in further experiments exactly the same lime water that was prepared before your eyes.

If you pour a little of this clean, transparent water into the jar where we collected the gas coming from the burning candle, you will immediately see how a change will occur... You see, the water has completely turned white! Please note that this will not work with ordinary air. Here is a vessel with air; I pour lime water into it, but neither oxygen, nor nitrogen, nor anything else present in this amount of air will cause any changes in the lime water; no matter how we shake it up with the ordinary air contained in this vessel, it remains completely transparent. However, if you take this flask with lime water and bring it into contact with the entire mass of candle combustion products, it will quickly acquire a milky white hue.

This white, chalk-like substance in the water consists of the lime we took to make lime water, combined with something that came out of the candle, that is, precisely the product that we are trying to capture and about. I will tell you today. This substance becomes visible to us thanks to its reaction to lime water, where its difference from oxygen, nitrogen, and water vapor becomes apparent; This is a new substance for us, obtained from a candle. Therefore, in order to properly understand the burning of a candle, we should also find out how and from what this white powder is obtained. It can be proven that it is indeed chalk; If you put wet chalk in a retort and heat it red-hot, it will release exactly the same substance that comes out of a burning candle.

There is another, better way to obtain this substance, and in large quantities, if they want to find out what its basic properties are. This substance, it turns out, is found in abundance in places where you wouldn’t even think of suspecting its presence. This gas, released when a candle burns and called carbon dioxide, is found in huge quantities in all limestones, chalk, shells, and corals. This interesting constituent of air is found bound together in all these stones; Having discovered this substance in such rocks as marble, chalk, etc., the chemist Dr. Black called it “bound air”, since it is no longer in a gaseous state, but has become part of a solid body.

This gas is easily obtained from marble. There is some hydrochloric acid at the bottom of this jar; a burning splinter lowered into a jar will show that there is nothing in it except ordinary air to the very bottom. Here are pieces of marble - beautiful high-grade marble; I throw them into a jar of acid and it turns out to be something like a violent boil. However, it is not water vapor that is released, but some kind of gas; and if I now test the contents of the jar with a burning splinter, I will get exactly the same result as from the gas coming out of the outlet pipe above the burning candle. Not only is the effect here the same, but it is also caused by exactly the same substance that was released from the candle; In this way we can obtain carbon dioxide in large quantities: after all, now our jar is almost full.

We can also verify that this gas is not only found in marble.

Here is a large jar of water into which I poured chalk (the kind that can be found on sale for plastering work, that is, washed in water and cleared of coarse particles).

Here's a strong one sulfuric acid; It is this acid that we will need if you want to repeat our experiments at home (please note that the action of this acid on limestone and similar rocks produces an insoluble precipitate, whereas hydrochloric acid gives a soluble substance, from which the water does not thicken).

You may be wondering why I am doing this experiment in such a container. So that you can repeat on a small scale what I am doing here on a large scale. Here you will see the same phenomenon as before: in this large jar I produce carbon dioxide, which is identical in nature and properties to that which we obtained when burning a candle in atmospheric air. And no matter how different these two methods of producing carbon dioxide may be, by the end of our study you will be convinced that it turns out to be the same in all respects, regardless of the method of production.

Let's move on to the next experiment to clarify the nature of this gas. Here is a full jar of this gas - let's test it by combustion, i.e., in the same way as we have already tested a number of other gases. As you can see, it itself does not burn and does not support combustion. Further, its solubility in water is insignificant: after all, as you have seen, it is easy to collect above water. In addition, you know that it gives a characteristic reaction with lime water, which turns white from it; and finally, carbon dioxide enters as one of the constituent parts of carbonated lime, i.e. limestone.

Now I will show you that carbon dioxide does dissolve in water, although only slightly, and in this respect, therefore, differs from oxygen and hydrogen. Here is a device for obtaining such a solution. The lower part of this device contains marble and acid, and the upper part contains cold water. The valves are designed so that gas can pass from the bottom of the vessel to the top. Now I will put my apparatus into action... You see how gas bubbles rise through the water. We have had the apparatus in operation since yesterday evening, and we will undoubtedly find that some of the gas has already dissolved. I open the tap, pour this water into a glass and taste it. Yes, it is sour - it contains carbon dioxide. If it is drained with lime water, a characteristic whitening will result, indicating the presence of carbon dioxide.

Carbon dioxide is very heavy, heavier than atmospheric air. The table shows the masses carbon dioxide and some other gases that we have studied.

Pint Kubic. foot

(grains) (ounces)

Hydrogen. . . . 3/4 1/12

Oxygen. . . . 11 9/10 1 1/3

Nitrogen. . . . . . 10 4/10 1 1/6

Air. . . . . 10 7/10 1 1/5

Carbon dioxide. 16 1/3 1 9/10

The severity of carbon dioxide can be demonstrated through a number of experiments. First of all, let's take, for example, a tall glass in which there is nothing but air, and try to pour some carbon dioxide from this vessel into it. It is impossible to judge by appearance whether I succeeded or not; but we have a way to check (puts a burning candle into a glass, it goes out). You see, the gas actually overflowed here. And if I had tested it with lime water, the test would have given the same result. We ended up with a kind of well with carbon dioxide at the bottom (unfortunately, we sometimes have to deal with such wells in reality); Let's put this miniature bucket in it. If there is carbon dioxide at the bottom of the vessel, it can be scooped up with this bucket and removed from the “well”. Let's check with a splinter... Yes, look, the bucket is full of carbon dioxide.

Rice. thirty.

Here is another experiment showing that carbon dioxide is heavier than air. A jar is balanced on a scale; Now there is only air in it. When I pour carbon dioxide into it, it immediately sinks from the weight of the gas. If I examine the jar with a burning splinter, you will be convinced that carbon dioxide has actually entered it: the contents of the jar cannot support combustion.

Rice. 31.

If I inflate a soap bubble with my breath, that is, of course, with air, and drop it into this jar of carbon dioxide, it will not fall to the bottom. But first, I’ll take a balloon like this, inflated with air, and use it to check where the carbon dioxide level is approximately in this jar. You see, the ball does not fall to the bottom; I add carbon dioxide to the jar and the ball rises higher. Now let's see if I can, by blowing up a soap bubble, make it stay suspended in the same way. (The lecturer blows a soap bubble and dumps it into a jar of carbon dioxide, where the bubble remains suspended.) You see, a soap bubble, like a balloon, rests on the surface of carbon dioxide precisely because this gas is heavier than air. From the book What Light Tells You author Suvorov Sergei Georgievich

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