US2076279A - Liquid oxygen explosive - Google Patents

Description

Patented Apr. 6, 1937 UNITED STATES LIQUID OXYGEN EXPLOSIV E Henri Sauvage, Paris, France, assignor to lAir Liquide, Societe Anonyme pour lEtude & lExploitation des Procedes Georges Claude,

Paris, France No Drawing. Application July 24, 1934, Serial No. 736,721. In Great Britain August 3, 1933 Claims.

The present invention relates to liquid oxygen explosives which comprise a combustible material adapted to be impregnated with liquid oxy gen, particularly with regard to the sensitivity 5 of the said explosives, that is the ease with which they can detonate under mechanical actions, impact or friction. It is known that this sensitivity varies a great deal according to the quality of the combustible used and that, for a given combustible, the sensitivity can be reduced by adding to the combustible substances which are more or less fine, preferably very fine, and are chemically inert with respect to the oxygene. g. powders of talc, calcium carbonate and magnesium carbonate. For the same purpose it has also been proposed to add to the combustible a substance containing water or evolving water vapour.

However, these additions have the disadvan- 0 tage of diminishing the power of the explosive, whereas, according to the present invention, good results can be obtained with regard to the insensitivity whilst avoiding this disadvantage.

According to the present invention, the mateterial added to the combustible material and which is intimately mixed with the whole mass of said combustible material, is starch, which, being combustible in liquid oxygen, contributes to the force of the explosion.

Now it has been ascertained that the results obtained with a given content of starch in a cartridge of liquid oxygen explosive were not always constant and that this was to be ascribed to the varying content of the cartridge in humidity coming from the atmospheric air. A certain efficiency is already obtained when starch,

which has passed through a screen of 300 meshes to the French linear inch is added in a proportion of 10% in weight, to lampblack which constitutes a cartridge or a priming. But to obtain a suflicient insensitivity which is near to the insensitivity ofthe usual permanent explosives,

it has been ascertained that the percentage of starch should be brought up to about 30% of 4,5 the whole mass of the combustible placed in the cartridge, without it being necessary to go beyond that percentage. With this percentage of 30% of starch the security of the same cartridge which does not include starch is increased by a little more than 100% all other conditions remaining the same. Moreover, the cartridge ispractically unimpaired as regards sensitivity, by the unavoidable variations of the atmospheric humidity.

However, as a supplementary precaution, it will be advisable to ascertain just before use that the cartridge is not dry and even that it contains the quantity of humidity which has been settled beforehand, for instance 10% in weight of the cartridge. For this purpose, for instance, the external part of the cartridge is provided with a small round piece of paper sensitive to humidity and the coloring of which will show that the humidity contained in the cartridge has not come down below a certain limit.

In case the cartridge is enveloped with paper or tissue, it is obvious that this envelope must preferably be non-combustible; asbestos paper, if necessary perforated, the use of which has been known or a long time, is particularly suitable to obtain the maximum insensitivity.

In case there is desired to simultaneously obtain a cartridge the material of which should be agglomerated, the above proportion of starch will be used under the form of starch size which would ensure the rigidity of the cartridge.

It is to be noted that the addition of even 30% inweight of starch diminishes only by little the ability of the usual lamp-black to absorb liquid oxygen and that on the other hand it gives an explosive which has a relatively small disruptive power.

I claim:

1. A liquid oxygen explosive comprising an intimate mixture of a main mass of a solid combustible material which is sensitive to shock by mechanical action and of starch in a proportion suflicient to materially reduce the sensitivity of the explosive constituted by the main mass of said solid combustible material.

2. A liquid oxygen explosive comprising an intimate mixture of a main mass of a solid combustible material which is sensitive to shock by mechanical action and of starch, the proportion of starch amounting to 30%, in weight, of said mixture.

3. A liquid oxygen explosive comprising an intimate mixture of a main mass of a solid combustible material which is sensitive to shock by mechanical action and of starch in a proportion sufficient to materially reduce the sensitivity of the explosive constituted by the main mass of said solid combustible material, the mixture having a moisture content of 10%.

4. A liquid oxygen explosive comprising an intimate mixture of a main mass of lamp black and of starch in a proportion suificient to materially reduce the sensitivity of the explosive constituted by the main mass of said lamp black.

5. A liquid oxygen explosive comprising an intimate mixture of lamp black and of powdered starch, said starch being in a proportion between 10 and 30% of said mixture and having been passed through a three hundred mesh screen.

HENRI SAUVAGE.