RU2174852C2 - Starting brick composition usable with isolating respirator devices - Google Patents

Abstract

FIELD: medical engineering. SUBSTANCE: brick has potassium bisulfate in the amount of 50-69.5% by mass, aluminum powder - 0.5- 2.5 % by mass and potassium or sodium superoxide making the rest. EFFECT: high heat stability; high reliability in starting operation of the apparatus under negative temperature conditions. 2 tbl _

Description

 The invention relates to compositions of chemicals used in chemically bound oxygen insulating breathing apparatus.

 In the initial period of operation of the insulating breathing apparatus, the starting briquette should sharply intensify the development of the regenerative product and ensure the generation of oxygen for human respiration during its development. The launch of the starting briquette is usually carried out using an ampoule with sulfuric acid.

A known composition of the starting briquette for insulating breathing apparatus, containing as a base potassium peroxide and sodium peroxide and as activating additives aluminum powder, aluminum hydroxide and manganese dioxide (av. St. USSR N 1197679 MKI A 62 D 9/00, priority 17.01. 83). The decomposition time of the starting briquette of such a composition weighing 44.5 - 45.0 g at room temperature is 30-35 s. When the briquette is decomposed, moisture is released, which contributes to the development of a regenerative product in an insulating breathing apparatus, and 6.0 liters of oxygen. The maximum temperature during decomposition of 400 ^o C.

This composition of the starting briquette is selected by the applicant for the prototype. The disadvantage of this composition is the low heat resistance of the briquette (75-100 ^o C) and its inoperability at temperatures below minus 10 ^o C. This significantly affects the performance of insulating breathing apparatus, which should operate at temperatures from minus 40 ^o C to plus 50 ^o C. As a rule, compositions with low heat resistance do not withstand long periods of storage. So, the shelf life of a known starting briquette is no more than 3-4 years.

Суммарный тепловой эффект этих реакций равен 1,9 ккал/моль.The reason for the low heat resistance of the composition is the low heat resistance of aluminum hydroxide (150 - 180 ^o C), and the inoperability of the composition at low temperatures (below minus 10 ^o C) is explained by the sharp inhibition of the main reactions that determine the composition

The total thermal effect of these reactions is 1.9 kcal / mol.

 The objective of the invention is to improve the operational characteristics of the starting briquette of an insulating breathing apparatus by increasing its heat resistance and ensuring its performance at low temperatures.

The problem is solved by the invention, according to which the composition of the starting briquette includes potassium bisulfate, aluminum powder and alkali metal peroxide. The ratio of the components of the composition is the following, wt. %:
Potassium Bisulfate - 50 - 69.5
Aluminum powder - 0.5 - 2.5
Potassium and / or Sodium Peroxide - Rest
The heat resistance of the starting briquette of this composition is 120-145 ^o C, which allows to increase the shelf life of breathing apparatus up to 10 years. The composition stably operates in the temperature range from minus 40 ^o C to plus 50 ^o C and ensures the effective development of a regenerative product in this temperature range.

Суммарный тепловой эффект этих реакций равен

.The reason for the higher heat resistance of the proposed composition is the high heat resistance of potassium bisulfate (more than 210 ^o C), and the performance of the composition at low temperatures is ensured by a significantly higher chemical activity of the neutralization reaction (4) in comparison with the quenching reaction of superperoxide with water (2):

The total thermal effect of these reactions is

.

 Aluminum powder is used as an additional source of heat to evaporate the resulting water.

 A method of manufacturing a starting briquette of the claimed composition consists in grinding and mixing the starting components, followed by molding the mixture into briquettes of various configurations (blocks, tablets), depending on the type of insulating breathing apparatus for which they are intended.

 Examples of the claimed composition of starting briquettes are shown in table 1.

 The choice of the optimal quantitative ratio of the components of the briquette is due to the following.

,

.The content of potassium bisulfate (50-69.5 wt.%) Was established taking into account the formation of hot water vapor. Hot water vapor starting briquette condenses on a regenerative product, the main component of which is potassium peroxide, heat it and react with it by reaction (2) with the release of oxygen. The development of the process is naturally enhanced by the heat of reaction (5) and (6):

,

.

 The more hot water vapor the briquette emits, the faster the regenerative product activates with access to the stationary mode. For such a composition, the initial release of oxygen by a briquette may be sufficient only to fill the breathing bag (2-3 l), and oxygen for respiration comes from the regenerative product being developed in accordance with reaction (2).

The content of potassium bisulfate below 50% in the composition leads to delayed (up to 5 min) and unreliable (possible undeveloped) development of the regenerative product at low temperatures (minus 40 ^o C). The content of potassium bisulfate above 69.5% leads to failure of the briquette when it is started.

 The content of potassium bisulfate, as well as the total content of potassium and sodium superperoxides, are also determined by the specific requirements of the insulating breathing apparatus.

 The relative content of sodium and potassium superperoxides is determined by the shape of the briquette, the required mechanical strength, the range of operating temperatures and the required decomposition rate.

 The limits of the quantitative content of aluminum powder are determined by the requirements for the temperature regime of decomposition of the briquette. An aluminum content of more than 2.5% makes the briquette fire hazard due to the high decomposition temperature, and an aluminum content of less than 0.5% leads to a delayed decomposition of the briquette.

Laboratory tests showed that during the decomposition of briquettes made from the proposed composition, toxic substances are not released, the mechanical strength of the briquettes when pressed with a density of 1.30 g / cm ³ to 1.75 g / cm ^{3 is} satisfactory and in the process of decomposition of the briquettes blur, i.e. the remainder retains the shape of the briquette.

 The test results are shown in table 2. The tests were carried out on briquettes weighing 44-45 g according to standard methods in accordance with GOST B 25308-82. The moisture released by the briquette was evaluated using a special technique and calculations.

 As can be seen from the data obtained, the claimed composition of the starting briquette has a sufficiently high heat resistance, which allows to increase the shelf life of the insulating breathing apparatus up to 10 years.

Starting briquettes composition workable at low temperatures (up to minus 40 ^o C).

 At the same time, the allocated amount of hot water vapor allows you to reliably and in a short time (no more than 35 s) activate the regenerative product of the insulating breathing apparatus with the release of additional oxygen.

Claims (1)

The composition of the starting briquette for insulating breathing apparatus, containing alkali metal superoxide and an activating additive including aluminum powder, characterized in that as alkali metal superoxide is containing potassium and / or sodium superoxide, and the activating additive additionally contains potassium bisulfate in the following ratio of components, wt .%:
Potassium Bisulfate - 50 - 69.5
Aluminum powder - 0.5 - 2.5
Potassium and / or Sodium Peroxide - Rest

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