FI76066B - PYROTECHNIC DIMPATRONER. - Google Patents

Description

1 76066

Pyrotechnic mist cartridges - Pyrotechnic dimpatroner

The present invention relates to pyrotechnic mist charges based on halogen donors and metal powder and / or oxides or red phosphorus to which an alkali salt may have been added, which charges form a mist which is impermeable to the visible and infrared region.

Artificial mists have already been used in the technique to keep frost away from plantations (especially fruit or vineyards). In this case, either a smoke or oil mist or a fine aqueous mist is usually formed, which may additionally be stabilized with glycerin, fatty alcohols or the like and which is applied to the crop to be protected in a more or less thick layer. The purpose of this is to reflect the heat radiating from the ground and thus prevent cooling. To this end, these mists or clouds must persist for a long time, i.e. the loss due to condensation and wind movements must be compensated by reconstruction. Therefore, continuous devices are most often used for this purpose.

Another area of application of artificial fog is primarily in the military sector in the camouflage of military equipment, troops and vehicles. In the protection of troops and vehicles in particular, it is a question of keeping them out of the direct control of the enemy for a short time. For this purpose, a pyrotechnic charge is usually fired in the direction of the enemy, which is distributed like a fragmentary charge and forms many mist-forming particles which very quickly and evenly cover large areas under the mist (cf. DE-AS 30 31 369 and the literature cited therein).

A large number of different smoke or mist mixtures have been made known for this purpose. Examples are titanium tetrachloride, silicon tetrachloride, chlorosulfonic acid or combinations thereof with ammonia or sulfur trioxide used as liquid mist formers, or red phosphorus, HC mixtures (hexachloroethane / zinc / zinc oxide) and ammonium used as solid mist formers. In use, these substances are converted either through a secondary combustion reaction or through suitable products released in their mutual reaction. From the point of view of the quality of mist formation, the rate of formation, the concentration and quality of its spread and the duration of the mist are decisive. Mixtures suitable for all these purposes are currently known (cf. DE-AS 30 31 369).

See, for example, DE-OS 25 56 256, DE-OS 25 09 539, DE-OS 18 12 027 DE-OS 12 46 488, DE-OS 30 12 405, DE-OS 27 29 055 DE-OS 27 43 363 , DE-OS 19 13 790.

However, these mixtures have a very significant disadvantage in view of their widespread use in modern warfare technology. Whereas in the past it was sufficient to generate as thick a fog as possible in the visible space, current military observers also have access to infrared directional and thermal imaging equipment, which take advantage of the fact that military targets emit very strong thermal radiation from long distances. Because atmospheric components such as carbon dioxide and water vapor selectively absorb infrared radiation of a certain wavelength in the range of 0.7 to 1.5 μ, 2 to 2.5 μ, 3 to 5 μ, and 8 to 12 μ. Particular efforts are made to operate in the range of 8 to 12 μ, since interference from smoke, dust and normal fog is minimal in this range. Pyrotechnic nebulizers, on the other hand, therefore aim to ensure the highest possible absorption or reflection of IR radiation in this region.

In addition, most pyrotechnic mist cartridges contain corrosive, toxic or highly acidic components such as phosphorus pentoxide, hydrochloric acid, sulfuric acid, titanium or zinc salts, which at concentrations present in the mist are very harmful to humans and plants. In most current

II

3 76066 cartridges contain metal oxides, buffers and ammonium compounds, therefore care is taken to ensure that the mist formed is as weakly acidic or neutral as possible. It is therefore also an object of the invention to modify the known mist charges so that they react as little as possible with acid.

U.S. Pat. No. 3,983,816 discloses a spray charge which e.g. however, contains very small amounts of cesium nitrate, about 1% cesium nitrate, to "generate a radar signal". However, such an amount of cesium salt is far too small to provide effective IR absorption.

U.S. Pat. No. 3,274,035 describes a mist mixture for producing artificial rain. However, the publication of the mist charge contains alumina, potassium iodide and lithium iodide. There are no indications that the mist formed is impermeable in the infrared range.

Surprisingly, these objects are achieved by the spray charges according to the invention, which are characterized in that the spray charges are additionally mixed with 5 to 50% of cesium compounds which, when burned, disperse and absorb radiation in the infrared range.

This addition of cesium compounds surprisingly and quite decisively reduces the permeability of the mist to IT light, in particular, infrared light with wavelengths of 3-5 or 8-12 pm. To date, the cause of this has not been determined.

Since it is known that in the vicinity of infrared radiation up to 12 μm, cesium salts have no absorption at all, which can be derived from vibrations in which cesium ions participate (cesium halides have no vibrations at 7.2 μm and cesium nitrate as a nitrate group there can be no direct absorption of IR light. Since the amounts used are relatively small, averaging only 25% of the total mist charge, and thus the amounts of conventional mist-forming components are small, the increase in the number of particles in the dispersed system 4 76066 cannot be the cause of the phenomenon either. Since, based on the observations to date, the settling rate and condensability of the formed cloud clouds also do not differ from the values of the corresponding mist charges without the addition of cesium salts, the phenomenon does not appear to be due to an improvement in the binding effect of the formed particles. Assuming that these particles are roughly subject to Stoke's law, i.e. the settling rate is proportional to the square of the particle diameter, an increase in the particle diameter of 1 y of conventional spray charges to 10 y, which would be necessary for efficient binding in the IR range B to 12 μ, would mean a 100-fold increase in the settling rate. Therefore, it remains to be found in subsequent studies to find a satisfactory theory that would explain why the mist cartridges of the invention have a satisfactory consistency in both the visible and infrared regions.

It is also an object of the present invention to improve the mist yield of phosphorus-containing mist feeds.

Commonly used magnesium and titanium metals cause the ash content to be 60 to 70 Å after combustion of the charge charges.

Surprisingly, the efficiency of such spray charges can be improved by using zirconium / nickel alloy instead of magnesium and titanium, which preferably contains 70 Å of zirconium and 30% of nickel. In this way, the ash content of such charges can be reduced up to 5 S. Boron additions act in the same direction and further improve IR absorption.

Efficiency can be further improved by adding ammonium chloride.

tt 5 76066

A major advantage of the described mist charges is that they have a passive effect. This means that they do not have any heat generation of their own and thus do not change the environmental image in IR viewers.

The following examples have compared some of the spray cartridges according to the invention with corresponding spray cartridges to which no addition according to the invention has been made.

Example 1

Ammonium perchlorate mist 1.7 kg of ammonium perchlorate, 1.5 kg of zinc oxide, 0.8 kg of polychloroisoprene and 0.5 kg of ammonium chloride are made into a paste with a solution containing 0.5 kg of dioctyl phthalate per liter of methanol. The mixture is sieved through a sieve with a mesh size of 0.3 to 0.5 mm and dried on grates. The dried granulate is then compressed at a pressure of 500 to 1500 bar according to DE-AS 30 31 369 into compression pieces weighing about 50 g. The charge is formed according to Example 2 of DE-AS 30 31 369 by combining 20 compression pieces and an ignition charge in a plastic or metal shell.

The ignition charge contains the following components: Magnesium powder (1.2 kg), vivianite (0.9 kg), amorphous boron (2.39 kg), chlorinated paraffin powder (0.8 kg) and black powder flour (4.71 kg). First, magnesium powder and viviaanite are mixed together; then chloroparaffin dissolved in 2 liters of perchlorethylene is added and mixed. Amorphous boron is added and stirring is continued for 5 minutes. As the last component, black powder is added, mixed with the other components for 10 minutes, dried and pressed at a pressure of 1500 bar.

6 76066

In addition, 0.4 kg of cesium nitrate is mixed into a mixture as described above and processed in the same way into compression pieces weighing about 50 g. As before, a charge is formed by joining together 20 compression pieces and an ignition charge.

To assess the fog effect, three white plates heated to about 40 ° C at 10 m intervals are placed side by side in the terrain and observed at a distance of 100 m with infrared and optical viewing devices at wavelengths of 10 μ, 3.5 μ and 0.6 μ. Fog charges of the described composition are triggered by a driving charge of about 40 to about 50 m in front of the object, whereby in a few seconds a fog wall 3 to 15 m high and 25 to 40 m wide and deep is formed.

At a temperature of 22 ° C and a relative humidity of 48? I, the coverage ratios given in the following table are obtained.

Very good means 95-100% coverage, i.e. the subject can no longer be distinguished from the background. By good is meant 80-95% coverage, i.e. the object is almost indistinguishable. Moderate means 50-80% coverage. Poor means less than 50% coverage, so that the object can still be clearly detected.

Table 1 0.6 μ 3.5 μ 10 μ

Perchlorate good bad bad

Perchlorate / CsNOj very good good good

Example 2

Heksakloorietaanisumu

Efficiently mix 2.5 kg of hexachloroethane, 0.8 kg of zinc oxide, 0.4 kg of silicon powder, 0.3 kg of aluminum-7 6 0 6 6 powder and 0.3 kg of amorphous boron and make into a paste in a kneader using 2 kg of 10 percent live st o-mer binder solution in acetone. The mixture is made by the method of Example 1 into compression pieces, which are further isolated with a methacrylic resin coating and combined according to Example 1 into spray batches.

The same mixture, to which, however, 1 kg of cesium nitrate has been added, is similarly made into a spray charge.

The mist effect is determined according to Example 1. This gives the results shown in Table 2 below. The pH of the resulting mist is about 5-7. The elastomer consists of butadiene. Polybutadiene can also be used.

Table 2 0.6 3.5 μ 10 μ HC mixture very good moderate moderate HC / CsCl very good very very good good

Example 3

Red phosphorus mist 0.65 kg of red phosphorus, 0.15 kg of iron (III) oxide, 0.15 kg of aluminum powder and 0.15 kg of magnesium powder and 0.2 kg of 10% elastomeric binder are made into a paste and further processed according to Example 1 into compression pieces.

Mixtures containing an additional 0.40 kg of cesium nitrate are similarly compressed into compression pieces.

The mist effect is determined according to Example 1. The results obtained in this case 8 76066 are shown in Table 3.

Table 3 0.6 μ 3.5 / j 10 μ

Phosphorus very good bad bad

Phosphorus / CsNO ^ very good very good very good

Example k 0.65 kg of hexachloroethane, 0.2 kg of silicon powder and 0.15 kg of aluminum powder are mixed and pressed under low pressure into a shell to which a driving and ignition charge is combined.

Mixtures containing an additional 0.10 kg of cesium chloride are further treated in a similar manner.

The following mist effects are obtained: 0.6 μ 3.5 μ 10 μ HC mist good moderate moderate HC - CsCl very good very good very good

In the following examples, good recipes are given.

Butadiene (polybutadiene) is used as the binder.

Example 5 55% Red phosphorus 23% Cesium nitrate 12% Zirconium / nickel alloy 70:30 10% Butadiene 7 6 0 6 6 9

Example 6 55 8 Red phosphorus 20 S Cesium nitrate 4 8 Manganese powder 6% Zirconium / nickel alloy 70:30 5% Fine aluminum powder 10 8 Butadiene

Example 7 27 8 NH.C10.

4 4 Θ 8 Zr / Ni 70: 3 5 K Fine aluminum powder 25 8 Cs N03 25 8 NH.C1 4 10 8 Butadiene

Example 8 43.75 8 Red phosphorus 33.00 8 Cs NO3 6.00 8 Amorphous boron 4.75 8 Titanium powder less than 100 m / j 12.50 8 Polybutadiene

Example 9 43.75 8 Red phosphorus 33.00 8 Cs NO3 6.00 8 Amorphous boron 4.75 8 Zirconium / nickel alloy 70:30 12.50 8 Macroplast B 202 (Butadiene in solvent, manufactured by Fa. Hnekel, Dusseldorf, BRD).

Claims (9)

1. Pyrotechnic fog cartridges based on halogen emitters and metal powders and / or oxides or red phosphorus, optionally containing an alkali salt, which forms an impermeable fog in the visible and infrared range, characterized in that the fumes are further incorporated into the fumes - 50%, which during combustion is dispersed and absorb strain in the infrared range. 2. Pyrotechnic fog cartridges according to claim 1, characterized in that the content of cesium compounds is 5 - 25%. Pyrotechnic fog cartridges according to claim 1 or 2, characterized in that the cesium compound is cesium chloride, chromide, nitrate and / or oxide. 4. Pyrotechnic fog cartridges according to any of claims 1-3, characterized in that with the cesium compound, hexachloroethane containing silicon and aluminum in the form of metal powder is involved. 5. Pyrotechnic fog cartridges according to claim 4, characterized in that they contain 50 - 70% by weight of hexachloroethane 20 - 40% by weight of silicon and / or aluminum powder and 5-20% by weight of cesium compound. 6. Pyrotechnic fog cartridges according to claim 5, the phosphorus content of which is at most about 50% by weight, characterized in that they contain a zirconium / nickel alloy, preferably in an alloy proportion of 70/30. Pyrotechnic fog cartridges according to claim 6, characterized in that they additionally contain amorphous boron. II