US3537397A - Pyrotechnic signaling device having water reactive igniter - Google Patents

Description

nit ed States Patent Inventors William L. Ripley and 910,942 1/1909 McCombie Lloyd A. Smith, Bedford, Indiana 910,943 [/1909 McCombie Appl. No. 753,090 1,858,456 /1932 Mills Filed Aug. 16, 1968 2,459,267 1/1949 Dwyer et al..

Patented Nov. 3,1970 2,543,079 2/1951 Veek Assignee The United States of America, as 3,1 10,259 1 H1963 Van Dersarl represented by the Secretary of the Navy Primary Examiner Roben F. Stab] 102/16 102/16 l02/6X 102/16X 102/37.8 102/37.8

Attarneys- Edgar J. Brower, H. H. Losche and Paul S.

PYROTECHNIC SIGNALING DEVICE HAVING WATER REACTIVE IGNITER 4 Claims, 1 Drawing Fig.

US. Cl 102/37.8, l02/6,102/16 Int. Cl ..F42b /22,

1 F42b 22/28 F429 3/00 ABSTRACT: A pyrotechnic signaling device having a quantity Field of Search 9/83; f pyrotechnic composition f producing Smoke or flame and References Cited UNITED STATES PATENTS 650,210 5/1900 Wilson 9/8.3X 25 percent ofpowdered aluminum.

r vr'd1\;-f.=\nn2- 22' h I 20 =5" a water reactive material for igniting said pyrotechnic composition. The water reactive material is comprised of, by weight, of between and 55 percent of sodium peroxide, between 20 and percent of ferrosilicon and between 10 and Patented 0v. 3, 1970 INVENTORS WILL/A L. RIFLE) LLOYD 4. SMITH ATTORNEYS PYROTECIINIO SIGNALING DEVICE'l-IAVING WATER REACTIVE IGNITER BACKGROUND OF THE INVENTION The present invention relates to a signaling device and more particularly to a signaling device containing a pyrotechnic composition and which hasintended use in a water environment, such as on a submarine orother naval vessel.

Many types of signaling and marking devices are presently being used for marine purposes. For example, submarines frequently use pyrotechnic signals as a means-of providinga mark onthe ocean surface in order to show the relative position of the submarines to surface ships.

Various devices and means have heretofore been used-to ignite the smoke or flame composition which is.used for signal ing. For example,.in U;S. Pat. No. 3,l96,789,:issued-.luly'27, 1965, to Stanley M.. Fasigand Glenn C. Johnson, there is shown and described a sea water battery which is energized by water, and power from the battery is. used to igniteor explode squibs which, in turn, ignite a pyrotechnic composition.

The use of water activated batteries for activating pyrotechnic compositions has a shortcoming in that thesebatteries are normally designed for operation in sea water and must be modified for use infresh water. Once a modification is performed, the devices utilizing the batteries cannot be storedfor more than 24 hours.

SUMMARY OF THE INVENTION Inthe presentinvention, a quantity of pyrotechnic composition which, when ignited,.will produce either smoke or flame is packed in a container and a startercomposition is provided adjacent one end of the pyrotechnic composition. A water reactive composition is provided which is comprised of sodium peroxide, which acts as a heat. generator and oxidizer; aluminum,.which acts as a fuel;.and ferrosilicon, which acts as, a fuel, a reaction rate regulator and a clinker which holds heat during and justafter the reaction. The water reactive composition is preferably placed in a hermetically sealed container to preventdeterioration from humidity.

BRIEF DESCRIPTION OF THE DRAWING The figure of the drawing is-a longitudinal sectional view of a preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, a quantity of pyrotechnic composition 11 is packed in a cardboard container 12 and enclosed in an outer metallic container 13, which has a bottom portion 14 and a top portion 15.

By way of example, one pyrotechnic composition widely used by the military departments for producing smoke and flames is comprised, by weight, of percent of phosphorus, 36 percent of manganese dioxide, 7 percent of magnesium, 3 percent of zinc oxide, and 3 percent of linseed oil. A starter composition 16 is provided in the top end of the pyrotechnic composition 11 to facilitate the ignition of pyrotechnic composition 11. By way of example, starter composition 16 might be comprised, by weight, of six parts of lead peroxide, eight parts of silicon powder, and six parts of cupric oxide.

Water reactive material 17 is provided to ignite starter composition 16 and in order to facilitate assembly and prevent moisture from affecting the water reactive material 17, it is preferably placed in a thin-walled aluminum container 18 which is closed at the top by a piece of asbestos paper 19. A cavity 20 is provided in top portion and container 18 is positioned within the cavity so that the bottom of container 18 is adjacent to, and in contact with, starter composition 16. A closure top 21 and sealing ring 22 are provided to close cavity in order to prevent any water from prematurely igniting pyrotechnic composition 11. A pull-ring 23 is attached to closure top 21 to facilitate removal of top 21.

Water reactive material 17 has been mixed using between 35 and 55 percent, byweight of sodium peroxide, between 20 and 50 percent, by weight, of'ferrosilicon (Fe Si) and between l0 and 25 percent, by weight of powdered aluminum.

For optimum results, the aluminumshould have an average particle size of 60 micronsand theferrosilicon and sodium peroxide should be of a granulation which will pass through a No. 20 U. S. Sieve. Variation of particle size, however, can be tolerated andstill have an operable. device. In compounding and testingvarious formulaof water reactive material, it has been determined that if thecombined weightsof the sodium peroxide and powdered aluminumis less. than fifty (50 percent of the total weight the material will drown-out. The sodium peroxide serves as an oxidizer, while thealuminum and ferrosilicon serve as. fuels. The. ferrosilicon moderates the reaction andforms a dense solid clinker. which holds heat. When the combinedweights of the powdered. aluminum and sodium. peroxide exceed eightypercent of the. total weight, a clinker does not form. It hasbeen determined by experimentation-at the- US. Naval Ammunition Depot, Crane, Indiana, that an optimumformula is comprised, by weight, of 5 l .6 percent of sodium peroxide, 32.3 percent of ferrosilicon, and 16.1 percentof aluminum.

In preparing the water reactive material, the sodium peroxide, ferrosilicon, and. powdered aluminum are first separately sieved and then combined ina dry box having an atmosphere from which substantially all moisture has been removed. A quantity of the mixture is then placed in container 18 which is closed by, asbestos paper 19 which is held in position by a ring 24 and the crimping of the top edgeof container 18. The weightof' the water reactive. material which is.used is determined by. the amount. of energy demanded by the application. The heat output ofthe composition is-approximately 950 calones per gram.

The water-reactive igniter of. the present invention operates in both freshwater and sea water, as well as under the surface of the water. Safety and compatibility of the water-reactive igniter were shown to be satisfactory by tests conducted at the Naval Ammunition Depot, Crane, Indiana, with the following results.

Drop sensitivity-No fires at kg.-c1n.

Friction sensitivity-No fires at 7, 500 ft.-Ibs.

Electrostatic sensitivity-No fires at 0.18 joules.

Autoignition to1nporaturc-lguited after 5 seconds at 324 degrees C.

OPERATION By way of example, container 13 might be dimensioned and proportional so that it will float, with bottom portion 14 being submerged. When it is desired to ignite pyrotechnic composition 11, pull-ring 23 is first pulled thereby removing closure top 21. Container 13 is then tossed or mechanically ejected into the water, and water seeps or passes through the asbestos paper 19 to ignite water reactive material 17. Asbestos paper 19 tends to keep the heat from material 17 concentrated at the bottom, and aluminum container 18, which is thin-walled, is quickly melted or burned away, and starter composition 16 is 'ignited. Starter composition 16, in turn, ignites the it can thus be seen that the present invention provides a small, rather inexpensive, device for igniting pyrotechnic compositions and that no mechanically moving parts or electrical circuits are required. Also the igniter works equally well in either fresh water or sea water. Reliability of the device has been demonstrated at the Naval Ammunition Depot, Crane, Indiana, where test trials were conducted on 21 units and ignition ofthe pyrotechnic composition occurred every time.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. For example, instead of closure top 21, a tear top such as those commonly used on metal beer and soft drink cans, can be utilized to seal top portion 15 of container 13 and, upon pulling the tear top an aperture or opening is provided for the entry of water. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

We claim:

1. A pyrotechnic signaling device comprising:

a container;

a quantity of pyrotechnic composition in said container;

a first fire composition adjacent one end of said pyrotechnic composition;

a water reactive material for igniting said first fire composition, said water reactive material consisting of between 35 and 55 percent, by weight, of sodium peroxide, between 20 and 50 percent, by weight, of ferrosilicon, and between 10 and 25 percent, by weight, of'powdered aluminum;and

means for hermetically sealing said container.

2. A pyrotechnic signaling device as set forth in claim I wherein said container has a closed bottom portion and a top portion having an aperture therein and wherein said means for hermetically sealing said container are removably attached to said top portion for closing said aperture.

3. A pyrotechnic signaling device as set forthin claim 1 wherein said water reactive material consists of about 51.6 percent, by weight, of sodium peroxide, about 32.3 percent, by weight, of ferrosilicon, and about l6.l percent, by weight, of powdered aluminum.

4. A pyrotechnic signaling device as set forth in claim 1 wherein said pyrotechnic composition consists of about 51 percent, by weight, of phosphorous, about 36 percent, by weight, of manganese dioxide, about 7 percent, by weight, of magnesium, about 3 percent, by weight, of zinc oxide, and about 3 percent, by weight, of linseed oil, and wherein said first fire composition consists, by weight, of about six parts of lead peroxide, eight parts of silicon powder, and six parts of cupric oxide.

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