US2754761A - Incendiary pellet - Google Patents

Description

July 17, 1956 DQDDS INCENDIARY PELLE'I Filed March 27, 1941 FIG. 5

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FIG. 1 INVENTQR NUGENT DODDS 5Y0 I 62 E United States Patent I? flice 2,754,761 Patented July 17, 1956 INCENDIARY PELLET Nugent Dodds, Washington, D. C., assignor to the United States of America as represented by the Secretary of War Application March 27, 1941, Serial No. 385,582

Claims. (Cl. 102-90) The invention described herein may be manufactured and used by or for the Government for governmental purposes, Without the payment to me of any royalty thereon.

This invention relates to an incendiary pellet.

One object of the invention is to provide an incendiary pellet which will spontaneously ignite when exposed to the atmosphere until it is dry.

Another object is to provide an incendiary pellet which will be stable on storage in water or in other suitable liquid medium, or in an atmosphere saturated with moisture, but which will spontaneously ignite when exposed to normal atmosphere until it is dry.

Other and further objects of the invention will become apparent as the description of the invention proceeds.

In modern warfare one of the methods of destroying enemy property and personnel is the dropping of incendinary munitions from aeroplanes onto the targets. By this method the incendiary munition ignites any combustible material which it may contact, causing destruction to enemy property. Furthermore, such a munition causes burns of more or less severity to personnel with whom it may come into contact.

Incendiary munitions may be divided into two groups. In the first group there are those munitions which combine explosive properties with burning properties, there being a two-fold damage resulting from the combined effects of explosion and of setting fire to adjacent property or causing burns on personnel. The second group relates to those munitions which have a burning effect only. The subject of this invention is a pellet which has the above described burning effect only.

According to the invention an incendiary pellet is provided which consists of paper, cloth or similar material wrapped into a coil or roll, said roll having cavities at one or both ends, and having phosphorus in one or both cavities. The phosphorus is normally kept moist by a covering of wet felt or similar material, to prevent the spontaneous combustion of the phosphorus.

While the invention is not to be limited thereto, a method of preparing this pellet will now be described.

Figure l is a plan of the strip of paper or cloth before rolling.

Figure 2 is an elevation of the completed pellet.

Figure 3 is an enlarged section of the pellet with one indented end.

Figure 4 is a similar view with two indented ends.

Figure 5 is a view similar to Figure 1 of a modified form.

Figures 6 and 7 are a plan and elevation of another modification.

Figure 8 is a plan of one felt cap prior to assembly.

A strip of paper such as soft paper towelling or cloth 1 is soaked in a solution of potassium nitrate, is removed therefrom and is dried. The strip 1 is then soaked in melted paraflin, is removed therefrom, and While the paraffin is still soft the paper is rolled up into a substantially cylindrical unit or roll resembling a cigarette, and one or both ends thereof are pressed into form depressions 2 therein. A small lump of phosphorus 3 is slipped into these depressions or reservoirs, and the end or ends of the pellet, including the lumps of phosphorus in the depressions in said ends, are then covered with wet felt 4.

in some cases it is desirable to incorporate flaked mag ncsiurn in the pellet to obtain a higher temperature of burning. As shown in Figure 5, flaked magnesium 6 can be distributed over the strip 5 while the paraflin coating is still soft, whereby the magnesium particles will be embedded in the parafiin.

Another modification is shown in Figures 6 and 7. in some cases the incendiary pellet may fall close to but not in contact with a combustible material. To cause contact with adjacent material and thus start or spread a fire, a narrow strip of steel spring 7 is rolled into the pellet. This spring 7 is placed approximately in the center of the paper or cloth strip 8, and the final pellet is otherwise rolled and prepared as previously described with the spring 7 rolled inside the pellet. The tendency of the spring 7 to straighten out flat is normally overcome by the sealing of the paraffin.

When the pellet starts burning, the parafiin seal is gradually weakened until the spring tension predominates. Then the burning strip snaps open, as seen in Figure 6, and contact is established with additional combustible material.

In all forms of the invention, the felt cap 4 is permanently secured to the pellet. Various methods may be used to this end. As seen in Figure 8, the cap 4 is generally circular, and has a plurality of separate tabs 9 arranged circumferentially. These tabs 9 are bent downwardly into engagement with the outer wall of the rolled pellet and are secured thereto. These tabs may be secured by any cement or glue which is compatible with and will stick to the parafiin coating. Another method of securing the tabs is to coat the end of the rolled pellet with hot parafiin, such .as by a paint brush, then place the tab 4 in place and bend and press tabs 9 into contact with the soft paraflin. Still another method would be to provide a heated former having two semi-cylindrical members which would press the tabs 9 against the side of the pellet, at the same time heating the paraffin sufiiciently to cause adherence of the tabs to the softened paraffin.

In all assembly operations, the completed pellets must be promptly dropped into cold water, which serves to quickly harden any soft parafiiu, and wets the felt 4 to prevent combustion of the phosphorus.

Care must be taken that the main body or end of the felt caps 4 are not covered with parafiin, in order to allow passage of water to the phosphorus during storage and passage of air to ignite the phosphorus during use.

The combustion of the pellet is believed to be obvious. As long as the felt 4 is kept moist or wet, the phosphorus cannot ignite. When the felt dries out, air will pass through the porous felt and the phosphorus, will spontaneously ignite. The paper or cloth strip will take fire and the potassium nitrate will burn with a high tempera ture, as will the paraffin.

Until ready for use the entire pellet is kept moist by being covered with water or is kept in an extremely humid atmosphere. Preferably a plurality of similar pellets are kept covered with water in the same container. While water alone has been disclosed, it is within the scope of the invention to use any liquid which will keep the pellets out of contact with air and which will be otherwise satisfactory.

It is within the intent of the invention that the plurality of pellets made according to the invention are submerged in water in a suitable container, which water may be drained ofl just before flight, to reduce weight, and that the container thus loaded is carried in an aeroplane and that the pellets are removed from the container as needed and are dropped upon the targets selected. The invention is not to be limited to this particular method of dropping or placing the pellets upon selected targets, since many modifications will be apparent to those skilled in the art.

It will be understood that variations of this invention will be apparent to those skilled in the art without departing from the spirit of the invention nor exceeding the scope of the appended claims, such as the including of highly combustible material in the indentation that holds the phosphorus (e. g. Celluloid shavings or powder); the weighing of one end of the pellet to prevent too great a spreading of them when released over specific targets, to secure more direct flight downward.

Where the expression paper is used in the claims, it is understood to mean paper, cloth, or any other readily combustible substance.

I claim:

1. In an incendiary article of the class described: a cylindrical roll of inflammable material; spontaneously combustible matter in contact with said material; a reservoir in an end portion of said roll holding a combustion preventing substance in contact with said matter; and sealing means covering and encircling both said reservoir and said end portion of said cylindrical roll and being arranged and adapted to permit the dissipation of said substance and the subsequent admission of air to said matter.

2. In an incendiary article of the class described: a web of paper laden with inflammable material and rolled into a substantially cylindrical unit; spontaneously combustible matter in contact with said material; a reservoir in an end portion of said cylindrical unit holding a combustion preventing substance in contact with said matter; and sealing means covering and encircling both said reservoir and said end portion of said roll and being arranged and adapted to permit the dissipation of said substance and the subsequent admission of air to said matter.

3. The combination of claim 2, wherein said retaining means includes molten parafiin coated on said web.

4. The method of making an incendiary article of the class described that includes the following steps in sequence: impregnating a web of sheet material with a solution of an oxidizing agent; drying said web; coating said web with molten paraffin; introducing magnesium flakes into said molten paraflin before it has hardened; rolling said web to form a substantially cylindrical coiled unit before said paraflin has hardened; forming a depression in one end of said unit before said parafiin has hardened; introducing spontaneously combustible matter together with a combustion preventing substance into said depression; and sealing said matter and said substance therein with a material adapted to permit the dissipation of said substance and the subsequent admission of air to said matter. a

5. The method of making an incendiary article that includes the following steps; coating a web of combustible sheet material with molten paraflin; rolling said web to form a substantially cylindrical unit before said paraflin has hardened; forming a depression in one end of said unit; introducing spontaneously combustible matter together with a combustion preventive substance into said depression; sealing said matter and said substance therein with a permeable porous material adapted to permit the dissipation of said substance and the subsequent admission of air to said matter.

References Cited in the file of this patent UNITED STATES PATENTS 399,883 Graydon Mar. 19, 1889 1,166,265 Schofield Dec. 28, 1915 1,294,150 Ortiz Feb. 11, 1919 1,301,655 Conley Apr. 22, 1919 1,327,899 Bemisderfer Jan. 13, 1920 1,441,551 Adler Jan. 9, 1923 1,489,900 Ross Apr. 8, 1924 1,669,091 Kohn May 8, 1928 1,858,456 Mills May 17, 1932 2,258,868 Sherman Oct. 14, 1941 2,558,726 Barker July 3, 1951 FOREIGN PATENTS 4,796 Great Britain of 1894 453,795 Great Britain Sept. 18, 1936 850,398 France Sept. 11, 1939 OTHER REFERENCES Article in the New York Times (Newspaper), September 11, 1940, page 11, column 6, page 12, columns 5 and 6.

Article in the New York Times (Newspaper), September 13, 1940, page 4.

Claims (1)

1. IN AN INCENDIARY ARTICLE OF THE CLASS DESCRIBED: A CYLINDRICAL ROLL OF INFLAMMABLE MATERIAL; SPONTANEOUSLY COMBUSTIBLE MATTER IN CONTACT WITH SAID MATERIAL; A RESERVIOR IN AN END PORTION OF SAID ROLL HOLDING A COMBUSTION PREVENTING SUBSTANCE IN CONTACT WITH SAID MATTER; AND SEALING MEANS COVERING AND ENCIRCLING BOTH SAID RESERVOIR AND SAID END PORTION OF SAID CYLINDRICAL ROLL AND BEING ARRANGED AND ADAPTED TO PERMIT THE DISSIPATION OF SAID SUBSTANCE AND THE SUBSEQUENT ADMISSION OF AIR TO SAID MATTER.

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