DK164665B - PYROTECHNICAL RANGE - Google Patents

Description

in

DK 164665 B

The present invention relates to pyrotechnic smoke rates which produce smoke that is impervious to the visible and infrared spectrum.

Artificial smoke is used in the art firstly to keep 5 frosts away from plantings (especially fruit or vine plantings).

In addition, either smoke or oil mist is usually prepared, or a fine mist of water, which may also be stabilized with glycerin, fatty alcohols or the like, is sprayed and spread over the culture to be protected in a more or less thick layer to reflect it. radiated heat from the earth, thus preventing cooling. Accordingly, these fogs or clouds must be maintained for a longer period, ie. the losses incurred through condensation and wind movement must be continuously renewed. For this purpose, therefore, continuous working systems are preferably used.

15 Artificial fogs are also used above all in the military sector for blurring of military installations, troop formation and vehicles. Especially when protecting troop formation and vehicles, it is important to avoid direct observation of the opponent for a shorter period of time, to which a pyrotechnic charge, usually distributed like a shotgun, is usually dispensed and forms many smoke-producing particles which provide a very fast and regular blurring of larger areas (cf.

DE-AS 30 31 369 and the literature cited therein).

To this end, a large number of different smoke and fog mixtures are known. For example, titanium tetrachloride, silicon tetrachloride, chlorosulfonic acid or combinations thereof with ammonia or sulfur trioxide such as liquid fumigants or red phosphorus, HC mixtures (hexachloroethane / zinc / zinc oxide) and ammonium perchlorate / zinc oxide as solid fumigants may be mentioned. In use, these substances are converted either through a secondary combustion reaction or through the suitable products released by their reaction. Crucial to the quality of the smoke formation is the rate of formation, the concentration and shape of the distribution, as well as the duration of the smoke veil. Smoke mixtures suitable for all these purposes are already known (cf.

35 German submission no. DE-AS 30 31 369).

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2

See, for example, German publication publications 25 56 256, 25 09 539, 18 12 027, 30 12 405, 27 29 055, 27 43 363, 19 13 790, and German publication no. 12 46 488.

However, for a wide application in the modern defense technique, these blends have a considerable disadvantage. While the former mainly came to achieve a visible smoke as dense as possible, military observers today still have infrared detectors and thermal imaging equipment that exploit the fact that military targets, due to their energy conversion, emit very intense 10 heat radiation that can be detected at a great distance. Since certain wavelengths are selectively absorbed by atmospheric constituents such as CO2 and water vapor, such equipment preferably operates in the so-called "windows" of the atmosphere which are at 0.7-1.5 µm, 2-2.5 µm, 3-5 xm and 8-12 / xm. In particular, efforts are made to work in the area of 8-12 µm, 15 as disturbances due to smoke, haze and normal fog in this area assume a minimum. In contrast, it is the task of pyrotechnic smoke rates to provide an absorption or reflection of the IR radiation in this range that is as high as possible.

Furthermore, from EP-A 37,515 it is known to combine smoke from halogen-20 donors / metal powders or phosphorous smoke with an additional secondary smoke of organic acids or microballoons, thus obtaining larger agglomerates which also exhibit light absorption in the range> 8 µm. The alkali metal salts (sodium, potassium, lithium nitrate) used in these mixtures cause, inter alia, also a six-half effect (staining of the flame), which, however, is not suitable for altering the infrared absorption.

In addition, most pyrotechnic smoke kits contain corrosive, toxic or highly acidic components such as phosphorus pentoxide, hydrochloric acid, sulfuric acid, titanium or zinc salts found in the smoke at 30 concentrations which are extremely harmful to humans and plants. Therefore, in the addition of metal oxides, buffer substances and ammonium compounds, in most previous smoke rates, the smoke produced is only as slightly acidic as possible or neutral. The object of the present invention therefore lies in that

DK 164665 B

3 modify the known smoke rates in such a way that, if possible, they do not react acidically.

These tasks are surprisingly solved by the measures described in the requirements, ie. in addition, to known smoke rates 5 based on halogen donors as well as metal powders and / or oxides or based on red phosphorus, the smoke rate further containing alkali metal salts, further mixing cesium compounds which are dispersed and burning radiation in the infrared area.

By this addition of cesium compounds, the transparency of the smoke in IR light is surprisingly reduced considerably, especially in infrared light with wavelengths of 3-5 or 8-12 μπι, as it has not yet been established why this is due.

Since, as is well known in the near-infrared region, up to 12 μτη of cesium salts exhibit no absorbable tracings and for which the cesium ions are responsible (none of the cesium halides, the cesium nitrate exhibits only the nitrate group oscillation at 7.2 µm), a direct absorption of the IR light does not qualify for the effect. Since the amounts used are relatively small compared to the amount of the total smoke rate, corresponding to only an average of 20 25%, and compared to the other smoke-forming components are only present in small amounts, the increase in the particle number of the dispersed system cannot, either. be made responsible for the effect. Also, since the rate of sinking and condensability of the resulting smoke clouds does not differ from the corresponding smoke rates without the addition of cesium salts to date, no improvement in the scattering effect of the particles produced appears to be responsible for the effect. Assuming that Stoke's law applies to these particles as a first approximation, viz. that the sink rate is proportional to the square of the particle diameter, an increase of 30 the particle diameter from 1 µ in conventional smoke rates to 10 µ, which would be necessary for an effective spread in the IR range of 8 to 12 µπι, would increase the sink rate by a factor 100.

It must therefore be reserved for further studies to find a satisfactory theory as to why the pyrotechnic smoke rates according to

DK 164665 B

4 the invention exhibits a satisfactory density both in the visible and in the infrared range.

The present invention further has the object of increasing the smoke yield from phosphorus-containing smoke rates.

5 The commonly used metals magnesium and titanium lead to an ash content of 60-70% after burning the smoke rate.

Surprisingly, they succeed in increasing the efficiency of such smoke rates by using a zirconium / nickel alloy instead of magnesium and titanium, preferably with 70% zirconium and 30% nickel. The ash content of such rates can thereby be lowered to 5%. Addition of boron works in the same direction and further improves IR absorption.

By adding ammonium chloride, the efficiency can be further increased.

A major advantage of the smoke rates described above is that they are passively active. This means that they do not exhibit their own heat toning and therefore do not change the ambient image in infrared observation equipment.

In the following examples, a number of smoke rates according to the invention are compared with corresponding smoke rates without the addition of the invention.

EXAMPLE 1

Ammonium perchlorate smoke 1.7 kg aramonium perchlorate, 1.5 kg zinc oxide, 0.8 kg polychlorosprene and 0.5 kg ammonium chloride are processed into a paste with a solution of 0.5 kg dioctyl phthalate ill methanol. The mixture is pressed through a sieve with a mesh size of 0.3-0.5 mm and dried on trays. The dried granules are then compressed according to German Laid-Open Specification 30 31 369 at a pressure of 50-150 MPa for press bodies of approx. A total of 20 press members are united in accordance with Example 2 i

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5 German presentation written 30 31 369 with a spark plug in a plastic or metal casing to form a charge.

The ignition kit has the following components: Magnesium powder (1.2 kg), Berlin blue (0.9 kg), amorphous boron (2.39 kg), powdered chloro paraffin 5 (0.8 kg) and black powdered flour (4.71 kg). The magnesium powder and berlin blue are premixed; The chloro paraffin, dissolved in 2 L of perchloroethylene, is added and mixed. The amorphous boron is added and the mixing process is continued for 5 minutes. As the final ingredient, the black powder was added, mixed with the other ingredients for 10 minutes, 10 dried and pressed at 150 MPa.

The same mixture as above was further mixed with 0.4 kg of cesium nitrate and was similarly processed into press bodies weighing approx. 50 g. As before, a total of 20 press bodies, together with a spark plug in a casing, were united to a charge.

15 To assess the smoke effect, 3 to approx. 40 ° C heated white plates placed in the terrain at a distance of 10 m and observed at a distance of 100 m with infrared and optical observation apparatus at wavelengths of 10 μτα, 3.5 μτα and 0.6 μτα. Smoke charges of the above-described composition were ejected with the aid of a drive charge. 40-50 m in front of the target, where within 3 seconds a 3-15 m high and 25-40 m wide and deep smoke wall formed. At temperatures of 22 ° C and a relative humidity of 48%, the coverage conditions given in the following table were obtained.

By "extremely good" is meant a hedge of 95-100%, ie. the target can no longer be distinguished from the background. By "good" is meant a hedge of 80-95%, ie. the target can hardly be distinguished. "Moderate" means a hedge of 50-80% and "bad" means a hedge of less than 50%, by which the target can be clearly seen.

Table 1 30 _ 0.6 µ 3.5 / i 10 µ

Perchlorate good bad bad

Perchlorate / CsNOj very good good good

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EXAMPLE 2 Hexachloroethane smoke 2.5kg hexachloroethane, 0.8kg zinc oxide, 0.4kg silica powder, 0.3kg aluminum powder and 0.3kg amorphous boron were thoroughly mixed and 5 together with 2kg of a 10% elastomer binder solution in acetone converted into pasta in an altar. In the same way as in Example 1, the mixture was processed into press bodies which were isolated by a further coating of methacrylic resin and were combined to smoke charges in accordance with Example 1.

10 The same mixture as above, however, with the addition of 1 kg of cesium nitrate, was similarly processed into smoke charges.

The smoke effect was determined according to Example 1, whereby the values shown in the following Table 2 were obtained. The resulting smoke had a pH of approx. 5-7. The elastomer consisted of butadiene. Polybutadiene is also useful.

Table 2 0.6 μ 3.5 μ 10 μ HG mixture very good moderately moderate 20 HC / CsCl very good very good very good EXAMPLE 3 Red phosphorus smoke 0.65 kg red phosphorus, 0.15 kg iron (III) oxide, 0.15 kg of aluminum powder 25 and 0.15 kg of magnesium powder are kneaded with 0.2 kg of 10% elastomer binder and processed into press bodies according to Example 1.

Similarly, mixtures which further contain 0.40 kg of cesium nitrate are processed into press bodies.

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7 The smoke effect is determined according to Example 1, whereby the results shown in the following Table 3 are obtained.

Table 3 5 0.6 µ 3.5 µ 10 µ

Phosphorus very good bad bad

Phosphorus / CsN03 very good very good very good

Phosphorus / Rbn03 Extremely Good Extremely Good 10 EXAMPLE 4 0.65 hexachloroethane, 0.2 kg of silicon powder and 0.15 kg of aluminum powder are mixed and pressed under low pressure in a sleeve connected to a drive and ignition kit.

Similarly, mixtures which further contain 0.01-0.10 kg of cesium chloride are processed.

The following smoke effects are obtained: 0.6 µ 3.5 µ 10 µ HC smoke good moderate moderate 20 HC-CsCl very good very good very good The examples below show the tested recipes. As a binder, butadiene (polybutadiene) is used.

EXAMPLE 5 55% Red Phosphorus.

23% cesium nitrate.

12% Zirconium / Nickel Alloy 70:30.

10% butadiene.

DK 164665 B

EXAMPLE 6 55% Red Phosphorus.

20% cesium nitrate.

4% manganese powder.

5 6% Zirconium / Nickel Alloy 70:30.

5% Fine aluminum powder.

10% butadiene.

EXAMPLE 7 27% NH 4 ClO 4.

10 8% Zr / Ni 70:30.

5% Fine aluminum powder.

25% CsNO3.

25% NH 4 Cl 10% Butadiene.

EXAMPLE 8 43.75% Red Phosphorus.

33.00% CsNO3.

6.00% Amorphous boron.

4.75% Titanium powder, less than 100 μη.

12.50% Polybutadiene.

EXAMPLE 9 43.75% Red Phosphorus.

33.00% CsNO3.

6.00% Amorphous boron.

4.75% Zirconium / Nickel Alloy 70:30.

12.50% Macroplastic B 202 (butadiene in solvent manufactured by Henkel,

Diisseldorf, BRD).

Claims (11)

1. Pyrotechnic smoke rate which produces smoke which is impermeable in the visible and infrared area based on halogen donors as well as metal powders and / or oxides or based on red phosphorus, the smoke rate further comprising alkali metal salts, characterized in that the smoke rate is further admixed cesium compounds which, upon firing, disperse and absorb radiation in the infrared region. Pyrotechnic smoke rate according to claim 1, 10, characterized in that the content of cesium compounds is 0.5-50%. Pyrotechnic smoke rate according to claim 2, characterized in that the content of cesium compounds is 5-25%. Pyrotechnic smoke rate according to any one of claims 1-3, characterized in that the cesium compound contained is cesium chloride, cesium bromide, cesium nitrate or cesium oxide. A pyrotechnic smoke kit according to any one of claims 1-4, characterized in that the cesium compound is mixed into a hexachloroethane kit with silicon and aluminum as metal powder. The pyrotechnic smoke kit according to claim 5, characterized in that it contains 50-70% by weight of hexachloroethane, 20-40% by weight of silicon and / or aluminum powder and 1-20% by weight of cesium compound. The pyrotechnic smoke set according to claim 7, characterized in that the cesium compound is mixed in a smoke set containing red phosphorus. DK 164665 B Pyrotechnic smoke kit according to claim 7, characterized in that it contains zirconium / nickel alloy, preferably in the alloy ratio 70/30. Pyrotechnic smoke kit according to claims 8, 5, characterized in that it further contains amorphous boron. Pyrotechnic smoke rate according to claims 8 and 9, characterized in that it has the following mixing ratio: red phosphorus 30-50% zircon / nickel 3-15% 10 boron 5-20% cesium compound 5-25% and optionally aluminum powder in amounts of from 3 to 20%. Pyrotechnic smoke rate according to any one of claims 8-10, characterized in that it is added ammonium chloride in amounts of 5-25%.