Improvements in Explosive Compounds
Year: 1899

page_text: Date of Application, 31st Jan., 1899-Accepted, 2nd June, 1899
Improvements in Explosive Compounds,
I, JAMES O'BRIEN GUNN, of 222, Market Street, San Francisco, California, in
the United States of America, Manufacturer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, that is to say:-
This invention relates to improvements in explosive compounds, and more par-
ticularly to what is known as blasting powder.
The present compound consists of the following ingredients mixed in the pro-
portions, as to weight, approximately as set forth.
The preferred formula for the present compound consists as follows:-
Nitrate of sodium, 63% ;-mineral coal, 22% ;-and sulphur, 15%.
By the use of the term, mineral coal, we desire to be understood as meaning
generally any form of coal from which illuminating gas is at present manufactured.
Or in other words, any coal containing hydro-carbon gas. It is due to the expan-
sion and explosion of the hydro-carbon gases contained in, and liberated from the
mineral coal, that we obtain our efficiency, or rending power.
For the nitrate of sodium, nitrate of potassium may be substituted to produce
a more rapid-firing explosive. But it is doubted, at this time, whether the strength
or rending power of the explosive, is not materially diminished in proportion to
the rapidity with which the explosion transpires.
A somewhat inferior, but still effective compound is manufactured by omitting
from the formula above given, the sulphur. We find that the best results have
been obtained by the use of the ingredients in the proportions above set forth, in
which the hydro-carbonaceous compound is used in large proportion.
The process for the manufacturing of this explosive compound is as follows:-
The different ingredients in their mineral or crude shape, are pulverized, or ground
to a greater or less fineness. We find that the best results are obtained from a
grinding which will permit the particles to pass through a screen of from 50 to 100
meshes to the linear inch. When the ingredients are ground to a size larger than
would pass through a mesh of less than 50 to the linear inch, the explosive action
is slow and not as efficient. It is presumed that the hydro-carbon gases are not
evolved completely from the granules or particles of the mineral coal when too
large.
Each of the ingredients, is, by preference, ground separately, and then mixed.
They can, however, without deleterious effect be ground together. We have use.]
nitrate of sodium, because its action is slower than other nitrates and it permits
the desired action of evolving completely the hydro-carbon gases from the mineral
coal. While the nitrate of sodium is deliquescent in its usual form we have found
that it is so covered by the coal as to avoid deliquescence, and that the longer the
nitrate of sodium and the mineral coal are in intimate contact the more perfect
the action of the explosive seems to become; and this, even where the compound,
after being mixed has been exposed to the atmosphere.
The compound when exposed to the open air may be freely burned, there being
only sufficient apparent vitality contained therein to evolve the gases, which are
:

page_text: consumed as the ordinary illuminating gas is consumed. In ordinary packages,
such as boxes, or cans, this compound will not explode, or detonate, for the reason
that before sufficient heat is generated to evolve the hydro-carbon gases contained
in the mineral coal, the solder is melted and the cans fall to pieces, or are merely
parted by the expanding gases. While this is true in its action when not resisted,
when confined within strongly resistant walls, sufficient to maintain the gases
under pressure, until the time of explosion, the efficiency and rending power of
the explosive is equal to, if not greater than any of the known explosives.
While this process has been described as a dry process, or one in which the in-
gredients are mixed dry, this is not essential to the invention, as it may be formed
by a wet process as follows:
The mineral coal is pulverized to a suitable fineness, that most desired being
of a size which will pass through the meshes of a screen of from 50 to 100 meshes
to the linear inch. When ground crude nitrate of sodium, and chloride of sodium
are added to the mineral coal and both placed in a vessel of approximately twice
the necessary size to hold them. Enough water is added to the mixture to
thoroughly submerge the same and the water is boiled.
During the boiling the mixture is stirred to bring all of the particles in contact.
The stirring may be more or less thorough as desired, it not being necessary in
this process to stir as thoroughly as in the former processes. The quantity of
water most desired, is just sufficient to dissolve the nitrate of sodium. The boil-
ing is continued until the water is evaporated and the mixture becomes dry. As
the same is becoming dry more care is taken to stir the mixture to prevent its
caking.
When the mixture has become dry, the proportion of sulphur above mentioned,
after being ground to about the same fineness as mentioned with regard to the
mineral coal, is added to the mixture. We have found that the mineral coal be-
comes perfectly and thoroughly nitrated when the mixture is boiled, while at tem-
peratures less than 212° F., the nitration is more or less imperfect. By means
of this perfect nitration, the evolving of the explosive gases, from the mineral coal,
is equalized and more thorough.
While the advantages of boiling the mixture have been here set forth, we do
not wish to be understood as confining ourselves to that process only, as we are
aware, that approximately as good results may be obtained at degrees slightly
less than 212° Nor do we desire to be understood as stating that a substantially
good powder could not he manufactured by the combination of the ingredients
herein set forth under what is known as the ordinary wet process. Or in other
words, wherein the mixture is carried forward in a bath heated to less than 160°.
We have ascertained, however, that the most perfect powder is produced when
the temperature is not below 212°.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
1. An explosive compound, consisting of the mixture of mineral coal, nitrate
of sodium, and sulphur, ground into small particles and mixed together in the
proportions, substantially as described.
2. An explosive compound, consisting in the mixture of mineral coal, ground
into small particles, and mixed with a suitable chemical, adapted to produce a
heat sufficient to liberate the gases contained within the coal, and to ignite the
same, substantially as described.
3. The method of manufacturing an explosive compound, consisting in grinding
mineral coal, nitrate of sodium, and sulphur into small particles of a predetermined
size, separately and then mixing the same in a dry state, in proportion, substan-
tially as described.
4. The process of manufacturing explosive compounds consisting in grinding.

page_text: mineral coal, to a predetermined size, mixing it with nitrate of sodium and chloride
of sodium, immersing the mixture in water; boiling the mixture, or the water con-
taining the mixture, drying the mixture, and adding thereto the desired propor-
tion of sulphur ground to a fineness equal to or greater than the mineral coal,
substantially as described.
5. The process of manufacturing explosive compounds consisting in grinding
mineral coal, to a predetermined size, mixing it with nitrate and chloride of
sodium, immersing the mixture in water, heating the water and mixture to about
160° F., until the water is evaporated, and adding thereto the desired propor-
tion of sulphur ground to a fineness equal to, or greater than, the mineral coal,
substantially as described.
Dated this 31st day of January
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, and 5A, Market Street, Nottingham,
Agent for the Applicant.