US2098341A - Flashlight powder - Google Patents

Description

Nov. 9, 1937. A. KALBER FLASHLIGHT POWDER Filed March 2, 1936 Inventor Attorney:

45' ber of years with all known flashlightpowder Patented Nov. 9, 1937 PATENT OFFlCE FLASHLIGHT POWDER Albert Kalber, Pforzheim, Germany Application March 2, 1936. Serial No. 66.751

- 3 Claims.

Myinv ention relates tofiashlight powder to be used .as,a filling for flashlight cartridges to be ignited by apercussion cap forming part of the cartridge. and more especially it has reference to 5 a special and new powder mixture by which substantial improvements are obtained.

Flashlight cartridges filled with a mixture of metal powder such as aluminium and/or magnesium, together with additional substances containing oxygen for inducing a quick burning of the flashlight powder, are known in many instances. One suitable mixture, which is probably the best known is described in my British Patent No. 419,658, and consists of 700 to 900 parts of magnesium, 10 to 18 parts of sulphur,

100 to 140 parts of potassium permanganate, '70 to 85 parts of potassium nitrate, 100 to 160 parts of ma nesia and 10 to 30 parts of wood charcoal. Whereas the particular composition of this known flashlight powder is such that a detonation of the light generating and burning metal with the said other substances during the firing can be avoided, this powder is not quite satis-' factory in every respect-because it is necessary to make special arrangements by which the powder in the cartridge will be continuously held under a certain mechanical pressure so as to prevent an unmixing and'separating of the different substances from taking place during transport, as this apparently renders the powder incapable of a reliable ignition and a quick burning thereafter. In the above mentioned British patent I proposed to apply for such purpose, a closing prop consisting of felt or the like elastic material,

35 holding the powder under a slight pressure. Al-.

' though the application of'this prop has been quite successful in avoiding the unmixing. it'is attended by several serious-handicaps or draw backs, especially if the cartridge is to be fired in- 40 doors, and it is the object of the present invention to prevent the unmixing of the powder mixture without having to apply any special means :10 hold the powder under mechanical compreson. Q

I have made extensive experiments 'fora nummixtures, comprising, amongst others, substances such as potassium chlorate, nitrates, sulphates and the -like, but none of these has been found 50 to be satisfactory. Finally, I succeeded in discovering a' mixture embodyingcarefully selected materials as stated hereinafter and in the selection of which care was taken that they have in addition or apart from the necessary charac- 55 terlstics to av d a detonation when fired and to be capable of discharging suflicient oxygen for the burning of the metalpowder, also the special characteristic that their specific weight is rather close to that of the material to be burnt. It was found in these tests that when care was taken 5 that only such materials which showed only a slight difference in the specific weight were employed, there is no real tendency of the carefully mixed powder to unmix during the transport,

so that even after a long shaking, as may take 10 place during transport of the cartridge, the different parts will not separate from each other, even if the powder in the cartridge is not held under compression.

The invention will now be further described 15 with reference to the accompanying drawing which will facilitate its understanding.

In said drawing:

Fig. 1 shows on a somewhat enlarged scale a longitudinal section through a cartridge; and Fig. 2 illustrates diagrammatically the arrangement of the extremely finely I subdivided and mixed difierent materials, upon a greatly magnified scale.

Referring to the drawing, a (Fig. 1) represents the cartridge which in its outer form corresponds substantially to known flashlight cartridge forms, such as that shown in my before mentioned British Patent No. 419,658, and is provided as in that example with a detonation cap I) in the bottom which is charged there, as described in the patent, with a potassium chloratephosphorus mixture. It may be mentioned here that the filling of the percussion cap does not form any direct part of the invention. This cartridge is filled with the powder mixture 0 of the new composition that is described below. With this "new filling it has been found to be unnecessary to close the upper end of the cartridge, opposite the percussion cup, by a prop of felt or the like as in said patent, and that it is quite suflicient simply to arrange here a thin paper or card disc d suitably'flxed, as for instance by gluing.

In my before mentioned experiments I found that a powder mixed in the following way or by the following formula does not, when ignited by the firing of the percussion cap, cause a loud detonation or explosion, but burns surely and quickly, and keeps its favourablefeatures even if the cartridge was before use subjected to shaking during transport or handling, because by the special selection of the substances an unmixing is entirely avoided.

The mixture found adapted to this purpose 55 teria1s are arranged in the mixture.

designated quantities, namely:

' Parts by weight Magnesium (Mg) 120to140 Aluminium (Al) 25 to' 32 Calcium (alabaster) carbonate I (CaCoa) or calcium alabaster,

meaning specifically finelyground calcareous alabaster 45 to 56 Silica (SiO2); 18 to 24 Magnesia usta (Mg repeatedly glowed 8to 12 The preferred mixture will contain:

. Parts by weight Magnesium (Mg) 130 I Aluminium (Al) .1. 30

Calcium (alabaster) carbonate (CaCOa) as above defined 50 Silica (SiOz) 20 Magnesia usta (Mg 0) as above specified 10 If it is desired to have the flashlight powder burn with a special color, then in known manner metal oxides influencing the color, such as an oxide of strontium, may be added in small quantities, for instance, in 2 to parts by weight. The different parts of the mixture must be most carefully ground and then very carefully mixed. It is necessary that raw material of very high quality is used, especially the calcium (alabaster) carbonate, or calcium alabaster, must be used in an extremely'pure and fine form. As suitable raw material, only extremely finely ground or shaved calcareous alabaster is to be used, whereas the oxide of magnesium is tobe used in the form of repeatedly glowed magnesia usta. The powdered magnesium is intermixed with aluminium ground to extreme fineness, such that during the mixture the metallic parts of the magnesium are so-tospeak surrounded and protected against oxidation by the very fine parts of the aluminium dust.

In Fig. 2 it is endeavored to show rather diagrammatically how the parts of the different ma- By small horizontal strokes the magnesium forming the main part of the mixture is indicated, whereas the extremely finely powdered aluminium is shown by small dots, although it cannot be shown how the parts of magnesium are enclosed in a protecting layer of aluminium dust. It should be mentioned here that it is known to use as flashlight powder magnesium aluminium alloys, which alloy how ever is not sufficiently resistive against oxidation.

2,098,341 contains the substances named below in the In the figure also the small vertical strokes indicate the parts of the calcium (alabaster) carbonate (CaCO3) or calcareous alabaster and the small crosses indicate the silica, while the small circles indicate the ground and repeatedly glowed magnesia usta (Mg 0) The powder so far described is not explosive in any way, so that it may be filled into thecantridge even with considerable: pressure. The closing paper or card disc serves 'onlyithe purpose of closing and keeping the cartridge filled. The term finely ground calcareous alabaster '(CaCOa) as hereinafter-used in the claims is intended to mean calcium carbonate (C9003) or calcium alabaster, i. e. having reference specifically to al'abaster of'a calcareous nature which is finely ground.

Having now particularly described and ascertalned the nature of my said invention and in what manner the same is to be performed, I declare that what I claim as new and desire to secure by Letters Patent '01? the United States Finely ground calcareous alabaster (CaCOa) 45 to 56 Silica (S102) 18 to 24 Repeatedly glowed magnesia usta (Mg 0) 8to 12 2. A powder mixture for aflashlight cartridge filling, consisting of:

Parts by weight Magnesium (Mg) 130 Aluminium (A1)--. 30 Finely ground calcareous alabaster (CaCOi) 50 Silica (SiOz) 20 Repeatedly glowed magnesia usta (Mg 0) 3. A flashlight powder mixture used in a flash light cartridge, which consists of substantially:

Parts by weight Magnesium (Mg) 130 Aluminium (Al) 25 to 32 Finely ground calcareous alabaster (CaCOal -1 45to 56 Silica (SiOz) 18 to 24 Repeatedly glowed magnesia. usta (Mg O) 8to 12 ALBERT

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