RU2614028C1 - Method for cooling respiratory gas mixture in respiratory individual protective equipment - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: respiratory gas mixture (RGM) is passed between fibrous supporting structures on which a coolant is preliminarily applied to one or both sides, while as coolant the mixture of solid high molecular saturated hydrocarbons modified by nanomaterial is used. The mixture of modified parafins with different phase transition temperature is used as the coolant. As a nanomaterial, carbon nanostructured material "Taunit" is used, which is the mixture of carbon nanotubes of "Taunit" or "Taunit-M" type in the quantity (wt.%) from 0.5 to 10, or nanographite (polygraphene) in the quantity (wt.%) from 0.2 to 6 is used. Nodeless net is placed into a gap between fibrous supporting structures with applied coolant. The use of claimed method allows to enhance RGM cooling efficiency by 25-40°C for generation comfort respiration conditions.

EFFECT: simpler servicing of respiratory protective equipment and providing the possibility of long-term storage thereof in live condition.

5 cl, 2 tbl, 1 dwg

Description

The invention relates to the field of rescue equipment, and in particular to personal protective equipment for respiratory organs, mainly of the pendulum type, operating on chemically bound oxygen.

In recent years, both in Russia and in other countries, regenerative products based on powdered potassium superoxide, formed in the form of granules, tablets or blocks, have been used as an oxygen source in insulating self-rescuers and respirators. These products absorb carbon dioxide and emit oxygen, however, during regeneration, large heat releases and drying of the breathing mixture occur, since water vapor also participates in chemical reactions. This leads to an increased temperature during inspiration (up to 65-75 ° С), a decrease in the relative humidity of the mixture (up to 0%) and excessive heating of the self-rescuer (respirator) structural elements. In normal operation, due to heat exchange with the walls of the respiratory tract, the temperature of the respiratory gas mixture (DGS) can drop to 45-55 ° C, however, in severe conditions, the temperature can rise to 70-80 ° C, which can lead to overheating of the body and burns the lungs .

There is a known method of cooling DGS, which consists in the fact that the gas mixture during inhalation and exhalation is passed through a filter heat exchanger in the form of a porous metal plate made of foamed metal, for example, foam nickel or foamed. At the initial temperature of the DHS of 75 ° C and the initial temperature of the filter-heat exchanger of 37 ° C with complete mutual heat exchange according to the known method, the mixture is cooled to 20-22 ° C (RF Patent No. 2291727, IPC A62B 7/08. A62B 19/00, 2007 .). The disadvantages of this method is the high resistance to breathing and insufficient cooling efficiency, especially in severe respiration conditions, when the heating of the GDS can reach 60-65 ° C.

A known method of cooling the respiratory mixture is that a refrigerant is placed in a closed metal container (refrigerator) —crystalline disubstituted sodium phosphate with a melting point of 34-36 ° C, and DHA heated as a result of the regeneration reaction is passed around this container (Insulating oxygen respirator P -12. Instruction manual. - Donetsk, Central Scientific Research Laboratory of State Duma, 1969. - S. 34-37). The essence of the known method lies in the fact that a homogeneous melt of refrigerant heated to + 60 ° C is poured into the refrigerator in a volume of 800-830 g and the refrigerator is cooled, moreover, at a temperature above + 34 ° C, the refrigerant melts and as a result of heat exchange through the walls of the DGS during 1 h is cooled by 1-3 ° C. After the transition to the melt, the temperature of the refrigerant begins to increase and at + 60 ° C it loses its cooling properties.

The disadvantages of this method are the short duration (40-60 minutes) and low cooling capacity (1-3 ° C).

Also known is the prototype method of cooling the respiratory gas mixture in personal protective equipment of the respiratory system operating on chemically bound oxygen, including the use of refrigerant (RF Patent No. 2330697, IPC A62B 7/08, 2008). According to the method, the respiratory mixture is passed by inhalation and expiration directly through the refrigerant, inorganic salts are used as the refrigerant, which can form crystalline hydrates upon expiration as a result of interaction with water vapor followed by their thermal decomposition during inhale. Inorganic salts are applied to the inorganic fibrous material, and after application to the fibrous material, the refrigerant is dehydrated.

Thus, the known method involves in the process of breathing the periodic formation and thermal decomposition of crystalline hydrates of inorganic salts.

The disadvantages of this method are the difficulty of maintaining equal flow rates through the entire living section of the fibrous substrate with crystalline hydrates. In addition, the known method provides dehydrated air to the regenerative product, which will cause a natural decrease in the temperature of the DHA on inspiration due to the worse functioning of the regenerative product, since water is required to absorb carbon dioxide and release oxygen. And the worst work of a regenerative cartridge will require an increase in its mass.

The authors of the known method are doubtful that applying these salts to fibers of inorganic material can significantly reduce the aerodynamic resistance of the pathways of the respiratory mixture through the absorber compared to other methods of cooling DGS:

The objective of the invention is to increase the cooling efficiency of the respiratory gas mixture.

The technical result of the invention is to reduce weight and size characteristics and reduce breathing resistance.

The technical result is achieved by the method of cooling the respiratory gas mixture in personal protective equipment of the respiratory system operating on chemically bound oxygen, including the use of a refrigerant deposited on the fibrous substrate, the respiratory gas mixture is passed during inhalation and exhalation through the cooling element, and the gas mixture is passed between the fibrous substrates, on which the refrigerant is preliminarily applied on one or both sides, which is used as a mixture of high molecular weight solid carbon limit hydrogen species modified with nanomaterial.

As a refrigerant, a mixture of modified paraffins with different phase transition temperatures can be used.

As the nanomaterial can be used a mixture of nanotubes of the type "Taunit" or "Taunit-M" in the amount of wt. % from 0.5 to -10.

As the material can be used nanographite (polygraph) in the amount of wt. % 0.2 to 6

In the gap between the turns of the spiral can be placed a tape from a knotless mesh.

Passing the gas mixture between the fibrous substrates, on which the refrigerant is preliminarily applied on one or both sides, using a mixture of solid high molecular weight hydrocarbons of a limiting nature, modified with nanomaterial, provides:

- reduction of breathing resistance due to the choice of the optimal gap between the substrates,

- reduction of material consumption due to the use of materials with a greater specific heat-absorbing ability,

- increased reliability; since to start the operation of the cooling elements is not required, as in the prototype, the saturation of the refrigerant by expired moisture, and the duration of this process depends on the ambient temperature,

- comfort of breathing due to the greater temperature difference of the flows during inhalation and exhalation.

The use of a mixture of modified paraffins with different phase transition temperatures as a refrigerant provides an increase in the electrical and thermal conductivity of the refrigerant. In this case, the material becomes form-stable and does not flow at the phase transition temperature. It was established experimentally that by changing the ratio of modified paraffins, it is possible to provide a temperature difference of up to 40 ° C.

Use as a nanomaterial a mixture of nanotubes of the “Taunit” or “Taunit-M” type in the amount of wt. % from 0.5 to 10 provides an increase in the thermal conductivity of paraffin from 0.238 W / m ° C before modification to 0.37 W / m ° C after modification.

Use as nanomaterial nanographite (polygraph) in the amount of wt. % from 0.2 to 6 increases the thermal conductivity of paraffin from 0.238 W / m ° C to 0.52 W / m ° C.

The space in the gap between the substrates coated with a knotless refrigerant mesh reduces breathing resistance to a comfortable level and maintains a constant gap during prolonged storage and during operation.

The essence of the proposed method is illustrated by an example and a drawing, which shows a schematic diagram of its implementation.

For the implementation of the invention, the following starting materials were used:

Paraffin is a mixture of solid high molecular weight hydrocarbons of a limiting nature, normal isostructure, with an insignificant admixture of cyclic hydrocarbons, obtained mainly from oil, ozokerite, and also synthetically - reduction of CO with hydrogen. The hydrocarbons that make up paraffin are divided into paraffins and ceresins.

Refined paraffin is a colorless product, odorless and tasteless, greasy to the touch, insoluble in water and alcohol, soluble in most organic solvents and mineral oils; when heated, soluble in many vegetable oils. The density of solid paraffin at 15 ° depending on its purity ranges from 0.881-0.905 g / cm ³ (crude paraffin) to 0.907-0.915 g / cm ³ (purified paraffin). Due to the heterogeneity of the composition of paraffin, the temperatures of the beginning and end of its melting can vary by 10-12 °. Poorly refined paraffin is yellow or brown in color and darkens in the light.

Below are the characteristics of the most used brand of paraffin.

Qualitative indicators of P-2 Paraffin oil solid

Thermal conductivity of paraffin - 0.238 W / m ° C; Modified by Taunite - 0.37 W / m ° С, Modified by graphene - 0.52 W / m ° С. In this case, the material becomes form-stable and does not flow at the phase transition temperature. The measurement was carried out on an IT - λ - 400 instrument in the mode of monotonous heating at an average rate of 0.1 ° C / s under adiabatic conditions. The use of a mixture of modified paraffins with different phase transition temperatures can provide a temperature difference of up to 40 C.

Carbon nanostructured material "Taunit". A mixture of carbon nanotubes (CNTs) and carbon nanofibres with a coaxial structure (UNVKS) with an outer diameter of 2-70 nm and a length of more than 2 microns. The content of carbon impurities is not more than 1% wt. Specific geometric surface (BET multipoint method) 90-130 m ² / g.

Multilayer carbon nanotubes "Taunit-M". Coaxial multilayer carbon nanotubes with an outer diameter of 8-15 nm and a length of more than 2 microns. The number of layers of one tube is 6-10. The content of non-carbon impurities is not more than 1% of the mass. Specific geometric surface (multipoint BET method) 300-320 m ² / g.

Nanographite (polygraph). Represents flakes of crystalline graphite with a diameter of 10 to 100 microns and an average thickness of 3-5 nm. Available as a paste in water or organic solvents with a mass content of nanographite of 6-10%. It can be used as an electrically conductive filler and to create electrically conductive coatings.

No-knot mesh made of polypropylene with a mesh size of 0.5; 0.8; 1,2; 1.5 and 2.0 mm. It is characterized by good thermal and chemical resistance.

Non-woven material from polypropylene "Spanbond with a density (g / m ² ) 15; 17; 21, 25 has high mechanical strength and hydrophobicity.

In FIG. 1 graphic materials shows a test scheme, which shows 1 - the body in the form of a pipe; 2 - the mesh is nodeless; 3 - a substrate with a refrigerant.

Example 1

In a container of dielectric material (silicone or polyethylene) with a volume of 0.01 m ³ , 0.002 kg of oxidized CNT Taunit was placed and 0.2 kg of paraffin grade P2 heated to 70 ° C was added. The mixture was sonicated at a frequency of 22.5 kHz for 1 hour while stirring with a mechanical stirrer (100 rpm). After cooling the material to a temperature of 50 ° C, reheating to 70 ° C was carried out, followed by sonication at a frequency of 40 kHz and stirring with a mechanical stirrer (100 rpm) for 20 minutes. Then they were re-cooled to a temperature of 50 ° C and re-heated to 70 ° C, followed by sonication at a frequency of 60 kHz and stirring with a mechanical stirrer (100 rpm) for 20 minutes. Got a black, opaque material. Next, the resulting material was applied to the surface of the spunbond, in the form of a tape, by grinding. After grinding, the ribbon obtained in this way was placed under an infrared heater with a dark emission spectrum to melt the upper layer and its subsequent penetration into the lower layers of the spunbond.

Example 2

In a container of dielectric material (silicone or polyethylene) with a volume of 0.01 m ³ , 0.002 kg of oxidized CNT Taunit-M was placed and 0.2 kg of paraffin heated to 70 ° C was added. The mixture was sonicated at a frequency of 22.5 kHz for 1 hour while stirring with a mechanical stirrer (100 rpm). After cooling the material to a temperature of 50 ° C, re-heating to 70 ° C is carried out, followed by sonication at a frequency of 40 kHz and stirring with a mechanical stirrer (100 rpm) for 20 minutes. Next, it is re-cooled to a temperature of 50 ° C and re-heated to 70 ° C, followed by sonication at a frequency of 60 kHz and stirring with a mechanical stirrer (100 rpm) for 20 minutes. Got a black, opaque material. Next, the resulting material is applied to the surface of the spunbond, in the form of a tape, by grinding. After grinding, the tape obtained in this way is placed under an infrared heater with a dark emission spectrum, which ensures the melting of the upper layer with its subsequent penetration into the lower layers of the spunbond.

Example 3

This example was carried out analogously to example 1, but graphene (Nanographite (polygraph)) was taken as the initial CNT. The mixture was sonicated at a frequency of 22.5 kHz for 1 hour while stirring with a mechanical stirrer (100 rpm). After cooling the material to a temperature of 50 ° C, re-heating to 70 ° C is carried out, followed by sonication at a frequency of 40 kHz and stirring with a mechanical stirrer (100 rpm) for 20 minutes. Next, it is re-cooled to a temperature of 50 ° C and re-heated to 70 ° C, followed by sonication at a frequency of 60 kHz and stirring with a mechanical stirrer (100 rpm) for 20 minutes. Received a dark gray, not transparent material. Next, the resulting material was applied to the surface of the spunbond, in the form of a tape, by grinding. After grinding, the ribbon obtained in this way was subjected to infrared heating with a dark emission spectrum to melt the upper layer and then penetrate it into the lower layers of the spunbond.

Example 4

This example was carried out analogously to example 1, but Taunit-M not oxidized CNTs were taken as initial CNTs. As a result, it turned out that the predominant part of the nanotubes after ultrasonic treatment is in sediment. Thus, when using non-oxidized CNTs under these conditions, only 2% of CNTs go into a colloidal solution, the rest precipitate. These data indicate that oxygen-containing groups on the surface of CNTs (hydroxyl, carboxyl, carbonyl, lactone) play an important role in the interaction with paraffin molecules. The conducted studies suggest that there is a chemical interaction of paraffin molecules with groups on the surface of carbon nanomaterial particles. Without the presence of oxygen-containing groups, the efficiency of paraffin modification is sharply reduced. Thus, the carbon surface of graphene layers of CNTs without oxygen-containing groups has a low affinity for paraffin.

Example 5

This example was carried out analogously to example 1, but instead of nanomaterial used various types of technical soot (grades: DG-100, DMG-80, PM-75, PM-50, PM-15 and TG-10). After heating and ultrasonic treatment, the soot settled on the bottom of the tank.

When a person breathes, the exhaled respiratory gas mixture has a temperature of about 37 ° C and is saturated with water vapor.

At a temperature of 37 ° C, the partial pressure of water vapor is 47.12 mm Hg, which corresponds to a concentration of 0.0453 g / l. For one exhalation, 1.75 L of DHA containing 0.0793 g of water vapor or 0.0044 mol enters the tube.

The measurement was carried out on an IT - λ - 400 instrument in the mode of monotonous heating at an average rate of 0.1 ° C / s under adiabatic conditions. The use of a mixture of modified paraffins with different phase transition temperatures can provide a temperature difference of up to 40 ° C.

Using the proposed method allows to increase the efficiency of cooling DGS by 25-40 ° C to create comfortable conditions for breathing. The method simplifies the maintenance of respiratory tract protection and provides the possibility of long-term storage of them in running order.

Claims (5)

1. The method of cooling the respiratory gas mixture in personal protective equipment for respiratory organs operating on chemically bound oxygen, including the use of a refrigerant deposited on a fibrous substrate, the respiratory gas mixture is passed during inhalation and exhalation through a cooling element, characterized in that the gas mixture is passed between the fibrous substrates on which the refrigerant is preliminarily applied on one or both sides, which is used as a mixture of solid high molecular weight hydrocarbons th character modified by nanomaterial. 2. The method according to p. 1, characterized in that the mixture of modified paraffins with different phase transition temperatures is used as the refrigerant. 3. The method according to p. 1, characterized in that as the nanomaterial use carbon nanostructured material “Taunit” - a mixture of carbon nanotubes of the type “Taunit” or “Taunit-M” in the amount of wt. % from 0.5 to 10. 4. The method according to p. 1, characterized in that the material used is nanographite (polygraph) in the amount of wt. % 0.2 to 6. 5. The method according to p. 1, characterized in that in the gap between the fibrous substrates with the applied refrigerant is placed a nodal net.

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