US3881968A

US3881968A - Incendiary comprising naphthalene and Mg-tetrafluoroethylene

Info

Publication number: US3881968A
Application number: US372554A
Authority: US
Inventors: Willard F Simpson; John N Sichra
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-06-22
Filing date: 1973-06-22
Publication date: 1975-05-06
Anticipated expiration: 1992-05-06

Abstract

A pressed composition of naphthalene and magnesium-Teflon powder is used as an incendiary bomblet fuel.

Description

Simpson et al.

INCENDIARY COMPRISING NAPHTHALENE AND MG-TETRAFLUOROETHYLENE Inventors: Willard F. Simpson; John N. Sichra,

U.S. Cl. 149/2; 102/6; 149/87 Int. Cl F24j 1/04; F42b 25/14 Field of Search 102/6; 149/2, 87

[ May 6, 1975 [56] References Cited UNITED STATES PATENTS 3,669,020 6/1972 Waite et al. 102/6 Primary Examiner-Leland A. Sebastian Attorney, Agent, or FirmR. S. Sciascia; Roy Miller; LLoyd E. K. Pohl [57] ABSTRACT A pressed composition of naphthalene and magnesium-Teflon powder is used as an incendiary bomblet fuel.

4 Claims, No Drawings 1 INCENDIARY COMPRISING NAPHTHALENE AND MG-TETRAFLUOROETHYLENE BACKGROUND OF THE INVENTION 1. Field of the invention This invention relates to incendiary compositions for use in jetting incendiary bomblets and a method for the preparation thereof.

2. Description of the Prior Art letting incendiary bomblets, i.e., incendiary bomblets which extend their effective range by producing jetting flames when activated, are well known. Such bomblets ordinarily contain a pyrotechnic composition which releases great quantities of heat and gaseous combustion products when burning and are provided with jet ports (holes) through which flames jet when the composition is ignited.

In the design of jetting incendiary bomblets, several factors must be taken into consideration. The bomblets must be of a size and shape to render them effective when interacting with target types of interest. The material which burns to produce the jetting flames must be safe to handle in manufacturing processes and yet be easily ignitable. The material must also burn in a manner whereby satisfactory jetting flames are produced. (That is, flames of sufficient size and temperature to ignite the target must be produced.) And, once it is ignited, the material should preferably be completely consumed and burn in a manner whereby clogging of the jet ports and, thereby, disruption of the working of the bomblet is avoided.

Prior art materials have been selected because of their ability to meet the standards suggested by the above factors. And, prior art materials have been highly satisfactory. However, in the broad field of weapon research, the search is continually on for new materials which might do the job better or do an equally good job less expensively. And, when suitable new materials are found, methods for the manufacture of articles using them must be developed.

SUMMARY OF THE INVENTION It has now been found that certain pressed mixtures of naphthalene and magnesium-Teflon (magnesiumpolytetrafluoroethylene) powder burn in a manner such that they are equal or superior to prior art jetting incendiary materials. The pressed compositions disclosed herein are safer to handle than magnesium- Teflon which does not have naphthalene added, easily ignited, burn cleanly and, as will be seen from the following discussion, produce highly satisfactory jetting flames.

DESCRlPTlON OF THE PREFERRED EMBODIMENT The preferred jetting incendiary composition according to this invention is a pressed grain containing 3parts by weight naphthalene and 1 part by weight Magnesium-Teflon powder.

Magnesium-Teflon is used, in the present invention, for two purposes. It heats the naphthalene to create a gaseous fuel and it results in the generation of pressure which expels the naphthalene fuel through the ports of the incendiary bomblet. The naphthalene fuel then burns when it contacts oxgen present in the atmosphere outside the bomblet. Other compositions containing differing ratios of naphthalene to Magnesium-Teflon may be used to alter the burning properties of the mixture and thus control the incendiary action. The naphthalene used may be either flake or powder.

The pressed compositions of this invention are prepared either by placing the mixture of materials in a bomblet casing or in a mold having the size and shape of the bomblet casing to be used, or a segment or portion thereof, and applying a pressure of from about 5,000 psi to about 8,000 psi for a duration of from about 10 seconds to about 30 seconds.

in the case where the bomblet casing itself is used as the mold, a cover may simply be placed on the casing after the pressing step is finished. In the case where a mold of suitable size and shape is used the pressed grain can be easily removed from the mold and placed in a casing of like size and shape.

As is well known, magnesium-Teflon powder is actually a powder made up of magnesium particles and polytetrafluoroethylene (Teflon) particles encased in a binder material such as motor oil, Viton A, Vitel, etc.. Magnesium-Teflon powder is so well known and so commonly used that it needs no further explanation here.

As is also well known, naphthalene is a solid at room temperature and remains a solid at temperatures considerably thereabove. Thus, the grains can be prepared at room temperature. Naphthalene comes from its manufacturers in both powder and flake form. Either is suitable for use in the practice of this invention.

A 3 to 1 weight ratio of naphthalene to Magnesium- Teflon has been found to be greatly preferred. ln tests comparing pressed grains prepared from 3 parts by weight naphthalene and 1 part by weight magnesium Teflon to pressed grains prepared from 4 parts by weight naphthalene and 1 part by weight magnesium- Teflon and to pressed grains prepared from 2 to 1 weight ratio mixtures of naphthalene and magnesium- Teflon, it was found that the 3 to l weight ratio grains were superior. They were superior in that the jets produced a higher temperature as witnessed by the fact that 3 to 1 jets ignited wooden ammunition boxes placed 12 and 18 inches away from the jet port whereas the 4 to 1 jets and the 2 to l jets would not. They were superior in that the 3 to l grains burned almost completely leaving only about 5% or less unburned material whereas both the 4 to l grains and 2 to l grains left from ID to 20% unburned material. They were superior in that no clogging of jet ports was observed when the 3 to l grains were burned as opposed to some clogging in cases where the 4 to l and 2 to 1 grains were used.

in other tests, grains were prepared both by the press ing method described above and by a slurry method wherein a solution of naphthalene in alcohol was mixed with magnesium-Teflon and the alcohol was allowed to evaporate. The grains prepared by the pressing method were superior in that they produced jets which would ignite wooden targets from l2 to 18 inches away from the jet ports and in only one case out of 10 bomblets did the grains fabricated by the slurry method ignite wooden targets placed at like distances from the jet ports.

In still other tests, grains containing 3 parts by weight naphthalene and lpart weight magnesium-Teflon and prepared by the pressing method described above were compared with state of the art grains of other magnesium-Teflon mixtures and with state of the art Alcast grains The grains of this invention were found to be superior to state of the art magnesium-Teflon grains and equal to Alcast grains insofar as target ignition was concerned.

One particularly desirable feature about the compositions of this invention is the fact that they can be pressed into almost any desired shape, This renders them suitable for use in any size or shape of container ordinarily used for jetting incendiary purposes of which there are many That is, any continer built to contain a solid grain, provided with means for igniting the grain and provided with jet ports may utilize the compositions of this invention. ln the above-described tests, canisters about 6 inches long and about 2 inches in diameter which were provided with a plurality of 9/32 inch diameter jet ports near one end were used to contain the grains. MagnesiumTeflon rods about 1 inch long and one-half inch in diameter were used to ignite the grains. It should be realized that with containers of different sizes than the ones used in the tests. different weight ratios of naphthalene to magnesium-Teflon may turn out to be preferable over the 3 to 1 ratio described herein We claim:

1. An article of manufacture fabricated by pressing a mixture consisting essentially of naphthalene and of magnesium-polytetrafluoroethylene powder into a suitable shape.

2. An article according to claim 1 wherein 3 parts by weight of naphthalene are provided for every 1 part by weight of magnesium-polytetrafluoroethylene.

3. A method for manufacturing an article of manufacture, said method comprising the steps of:

a. mixing about 3 parts by weight of naphthalene and 1 part by weight of magnesium-polytetrafluoroethylene particle in a container having a suitable shape; and

bi pressing said mixture at a pressure of from about 5,000 psi to about 8,000 psi.

4. In the method for starting a fire which comprises depositing a jetting incendiary bomblet in an area where ignitable materials are likely to be and activating a material within the bomblet to produce jetting flames the improvement which comprises utilizing a pressed grain of naphthalene and magnesium-polytetrafluoroethylene as said material.

Claims

1. AN ARTICLE OF MANUFACTURE FABRICATE DBY PRESSING A MIXTURE CONSISTING ESSENTIALLY OF NAPTHALENE AND OF MAGNESIUMPOLYTETRAFLUOROETHYLENE POWDER INTO A SUITABLE SHAPE.

3. A method for manufacturing an article of manufacture, said method comprising the steps of: a. mixing about 3 parts by weight of naphthalene and 1 part by weight of magnesium-polytetrafluoroethylene particle in a container having a suitable shape; and b. pressing said mixture at a pressure of from about 5,000 psi to about 8,000 psi.