Luminescent Aerosol Marker

Abstract

A method for forming a 3-dimensional marker for long range detection which omprises releasing an aerosol spray into the atmosphere consisting of a mixture of compounds whereby the reaction of the mixture produces a marker of light visible from any angle.

Description

GOVERNMENT INTEREST

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION

The invention relates to a method for forming a 3-dimensional chemiluminescent aerosol marker for long range detection.

In the search for long range detection by airborne observers many methods have been developed. Such chemical sources as tetrakis-(dimethylamino)ethylene are not suitable as aerosols due to long lived intermediates which limit maximum intensities to low orders. Chemiluminescent clouds have been made for simulated fallout studies; however, large particles (larger than aerosol) are required and are not adaptable to form markers. When these chemiluminescent materials are used as markers, they are primarily limited to two-dimension disseminated materials lying on the ground or on vegetation. The present invention produces a 3-dimensional signal easily detected at any viewing angle for longer duration per payload than any other known chemiluminescent marker.

DESCRIPTION OF THE INVENTION

In accordance with the present invention a luminescent aerosol cloud was formed by spraying into the atmosphere a liquid mixture of a solution containing oxalate ester selected from the group consisting of bis(2,4,6-trichlorophenyl)oxalate, bis(2,4,5-trichloro-6-carbobutoxyphenyl)oxalate and bis(2,4,5-trichloro-6-carbopentoxyphenyl) oxalate and a solution containing hydrogen peroxide in a ratio ranging from 2 - 10 parts oxalate to 1 part peroxide whereby the reaction between the oxalate and the peroxide produces a 3-dimensional light marker readily visible from any viewing angle.

In operation two storage tanks were provided, one containing 250 cc oxalate ester in the solvent, dibutylphthalate, and the other containing 80 cc of hydrogen peroxide in the solvent, 3-methyl-3-pentanol. The tanks were connected by a common tube to a pressurized nitrogen gas system which was provided with a pressure regulator. The storage tanks were both connected to a mixer by outlet tubes each of which was provided with metering devices for measuring the quantity of oxalate and peroxide transferred to the mixer. A nozzle was attached to the mixer for spraying the materials into the atmosphere. These materials are kept in separate containers until the desired cloud is to be formed because they begin to react with each other upon contact to form light. Catalysts may be added to the mixture to speed up the reaction. Sodium salicylate and t-butyl ammonium salicylate are two examples of successful catalysts. The oxalate esters used are solids and are dissolved in a compatible liquid solvent for use in one tank in accordance with this invention. Also, t-butyl alcohol, 3-methyl-3-pentanol and mixtures thereof are excellent solvents with hydrogen peroxide for use in the other tank. The cloud formed allows personnel to make the initial acquisition and the viewing angle is not limited by Lamberts law as in 2-dimensional markers. In time, the aerosol droplets which form the cloud marker gradually settle to the ground thereby creating an extension of the marker which provides for longer duration of light in essentially the same area. The present invention, therefore, provides a 3-dimensional chemiluminescent marker for initial acquisition in ranges from 5 to 10 miles and an extended 2-dimensional marker on the ground or foliage for about 2 miles for an additional time. Initial acquisition ranges from about 5 - 10 miles for about 1 minute per pound of mixed compounds. If the payload is 6 pounds or more, the two dimensional marker duration ranges from 5 or more additional minutes, minimum.

The color of the luminescent aerosol cloud marker formed has been varied with the addition of fluorescers to the oxalate estersolvent mixture. The fluorescer, 9,10-diphenylanthracene, produces a blue light; 9,10-bis(phenylethynyl)anthracene produces a green colored light, 5,6,11,12-tetraphenylnaphthacene produces an orange light, and 16,17-dihexyloxyviolanthrone produces an invisible (near-IR) marker.

Other means of mixing and spraying the mixture of compounds into the atmosphere to form an aerosol cloud marker may be used.

Claims

What is claimed is:

1. A method for forming an aerosol cloud marker which comprises

blending in a mixer, provided with a nozzle adapted to spray liquid into the atmosphere, liquid components from two separate vessels, one vessel containing a mixture of an oxalate ester selected from the group consisting of bis (2, 4, 6-trichlorophenyl) oxalate, bis(2, 4, 5-trichloro-6-carbolutoxy-phenyl) oxalate and bis(2, 4, 5-trichloro -6-carbopentoxyphenyl) oxalate and a compatible solvent and the other vessel containing a mixture of hydrogen peroxide and a compatible solvent; and

spraying said blended mixture into the atmosphere;

whereby the reaction between said oxalate ester and hydrogen peroxide produces a 3-dimensional light marker.

2. The method in accordance with claim 1 wherein a catalyst is added to said mixture containing hydrogen peroxide.

3. The method in accordance with claim 2 wherein the catalyst is a member selected from the group consisting of sodium salicylate and t-butyl ammonium salicylate.

4. The method in accordance with claim 1 wherein the solvent in the mixture containing hydrogen peroxide is a member selected from the group consisting of t-butyl alcohol, 3 methyl-3-pentanol and mixtures thereof.

5. The method in accordance with claim 1 wherein the solvent for the mixture containing the oxalate ester is dibutylphthalate.

6. The method in accordance with claim 1 wherein the cloud contains essentially from 2 to 10 parts oxalate ester to 1 part hydrogen peroxide.

7. The method in accordance with claim 1 wherein a fluorescer selected from the group consisting of 9,10-diphenylanthracene, 9,10-bis(phenylethynyl)anthracene, 4,6,11,12-tetraphenylnaphthacene and 16,17-dihexyloxyviolanthrone is added to said mixture containing the oxalate ester.