Improvements in the Manufacture of Gunpowder.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Gunpowder.
We, CHARLES WILLIAM CURTIS, of 74, Lombard Street, London, Gunpowder
Manufacturer, and ARTHUR HAMILTON DURNFORD, of Hanworth Lodge, Hanworth
Road, Hounslow, do hereby declare the nature of this invention to be as follows:-
This invention relates to the manufacture of an improved gunpowder suitable
for both blasting and propulsive purposes and particularly suitable for blasting
in dusty and fiery coal mines where explosive gases are developed, and where
ordinary blasting gunpowder is unsafe or is prohibited. Ordinary blasting gun-
powder as now used produces when exploded flame and incandescent particles of
so high a temperature, that when the same come in contact with the explosive
gases found in such mines such gases are under certain conditions readily ignited.
In gunpowder made under this invention the flame and incandescent particles
produced by its explosion are of such a different composition and are so much
lower in temperature and less in quantity that this gunpowder can be used with
safety in dusty and fiery mines. Ordinary gunpowder is usually made with three
ingredients, namely saltpetre, charcoal and sulphur and the charcoal usually
contains a high proportion of carbon, averaging 80 per cent. In carrying the
said invention into practice only two ingredients are used, viz.: saltpetre and a
charcoal so prepared as to have a comparatively low ignition point and to contain
a large proportion of oxygen and hydrogen. The sulphur ordinarily used is
entirely dispensed with. The proportions preferred are 80 parts of saltpetre
and 20 parts of a charcoal containing about 60 per cent. of carbon but we do not
confine ourselves to these proportions but may vary them, particularly when the
charcoal varies in composition--for example if the charcoal used contains say
68 per cent. of carbon the quantity of saltpetre would be about 82 per cent. and
the charcoal 17 per cent. The charcoal is prepared in iron cylinders at a very
low temperature, from preferably alder or willow wood or other suitable charcoal
producing material and should be prepared so as to contain preferably about
60 per cent. of carbon but this proportion of carbon however can be varied if the
proportion of the ingredients are also varied so as to give a theoretical chemical
result by which the oxygen of the saltpetre converts all the carbon of the charcoal
into carbon di-oxide (CO2). The variation in the carbon of the charcoal should
not be more than 70 per cent. or less than 50 per cent. The two ingredients are
ground fine and mixed together and are then incorporated and granulated in the
same manner as ordinary gunpowder. This gunpowder although having little
explosive power in the open air has when confined great strength and powerful
rending and propulsive action.
P
1900
THEO.
MCKENNA,
17 and 18, Basinghall Street, London, E.C.,
Applicant's Agent.

page_text: We, CHARLES WILLIAM CURTIS, formerly of 74, Lombard Street, London, but
now of 3, Gracechurch Street, London, Gunpowder Manufacturer, and ARTHUR
HAMILTON DURNFORD, of Hanworth Lodge, Hanworth Road, Hounslow, Manager
of Gunpowder Works, 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 : -
:----
This invention relates to the manufacture of an improved gunpowder suitable
for both blasting and propulsive purposes, and particularly suitable for, blasting
in dusty and fiery coal mines where explosive gases are developed, and where
ordinary blasting gunpowder is unsafe or is prohibited. Ordinary blasting gun
powder produces when exploded flame and incandescent particles of so high a
temperature that when the same come in contact with the explosive gases found
in such mines, such gases are under certain conditions readily ignited. In gun-
powder made under this invention, the flame and incandescent particles produced
by its explosion are of such a different composition and are so much lower in
temperature and less in quantity that this gunpowder can be used with safety
in dusty and fiery mines. Ordinary gunpowder is made with three ingredients,
viz.: saltpetre, charcoal and sulphur, and the charcoal usually contains a high
percentage of carbon, averaging about 80 per cent. In carrying the said inven-
tion into practice, only two ingredients are used, namely, saltpetre and a charcoal
so prepared as to have a comparatively low ignition point and to contain a
comparatively large proportion of oxygen and hydrogen. The sulphur ordinarily
used is entirely dispensed with.
The proportions preferred are 80 parts of saltpetre and 20 parts of a charcoal
containing about 60 per cent. of a carbon but we do not confine ourselves to these
proportions, nor to this percentage of carbon in the charcoal, but may vary them,
particularly when the charcoal varies in composition. For example if the char-
coal used contains say 68 per cent. of carbon, then, the proportions of the ingre-
dients would be about 82 parts of saltpetre and 17 parts of such charcoal,
while if the charcoal contains say 52 per cent. of carbon, then the proportions
of the ingredients would be about 78 parts of saltpetre and 213 parts of such
charcoal. Thus when the proportions of the ingredients are varied, with reference
to the percentage of carbon contained by a particular charcoal, they should be
such that the oxygen available from the decomposition of the saltpetre should,
theoretically, convert all the carbon of the charcoal into carbon di-oxide (C. O₂).
The percentage of carbon contained in the charcoal should, however, not be greater
than 70% or less than 50%.
The charcoal is prepared in iron cylinders from wood or other suitable charcoal
producing material, preferably alder or willow wood. The wood is put into the
cylinders and heated at a low temperature, until a certain quantity of the volatile
matter is driven off, so that the charcoal thus prepared shall still contain a large
percentage of volatile matter.
The quantity of volatile matter left in the charcoal varies, though not propor-
tionately, according to the percentage of carbon that it is desired for the charcoal
to contain for example, a charcoal which contains about 65 per cent. of carbon
will, approximately, give off when heated to redness in a current of coal
50 per cent. of volatile matter including of course a certain proportion of carbon
compounds while one containing 58 per cent. of carbon will in like manner give
off approximately 63 per cent. of volatile matter.
gas

page_text: It is an advantage in our gunpowder that a large proportion of its constituent
charcoal should be in the condition of the volatile matter estimated in the manner
above described and hence it is necessary to use for its manufacture a charcoal
having a low proportion of carbon as above described. We find that a charcoal
containing by analysis 70 per cent. of carbon is the richest in carbon which it is
at all useful to employ for this purpose, and we consider that it is advantageous
when making powder for blasting in fiery mines to use a charcoal containing less
carbon than this proportion, and to reduce the carbon constituent as much as
possible.
The saltpetre and charcoal are ground fine and mixed together, and are then
incorporated and granulated in the same manner as ordinary gunpowder.
This gunpowder although having little explosive power in the open air has,
when confined, great strength and powerful rending and propulsive action.
Having now particularly described and ascertained the nature of our said
invention, and the manner in which the same is to be performed, we declare that
what we claim is:
An explosive compounded of saltpetre and a charcoal such as is above described
in the proportions above specified the charcoal being characterized by the property
of yielding under the conditions above mentioned a large percentage of volatile
matter.
d the 19th day of May 1899.
THEO. MCKENNA,
17 and 18, Basinghall Street, London, E.C.,
Applicants' Agent.