Improvements in Explosives.
Year: 1899

page_text: Date of Application, 1st May, 1899
Complete Specification Left, 28th Feb., 1900-Accepted, 31s! Mar., 1900
PROVISIONAL SPECIFICATION..
Improvements in Explosives.
We. CHARLES HERBERT CURTIS, of 3. Gracechurch Street, London.
Explosives Manufacturer, and GEORGE GUILLAUME ANDRÉ, of Genlean, Argyll-
shire, Chemist, do hereby declare the nature of this invention to be as follows:-
The object of our invention is to produce an explosive suitable for guns and
|capable of being regulated in explosiveness so as to be adaptable to arms of any
calibre.
.
For this purpose we take as the basis of our new explosive ammonium pierate.
This salt of picric acid is but feebly explosive, and if is wholly resolvable into
gases. Hence it is peculiarly suitable as a basis on which to form an explosive
agent of the kind that we have in view. Moreover it is safe to manipulate for
it is not very liable to be exploded by a blow or friction.
This picrate does not contain sufficient oxygen in its composition to burn
completely the carbon constituent. In this respect it is very deficient, but this
deficiency furnishes us with the opportunity of regulating the explosiveness
of a mixture of which the picrate forms the basis, for by adding an oxygen
carrier, in which capacity we find it very advantageous to use barium nitrate
in proper proportions, which must be determined with reference to the duty
which the explosive is to perform, the heat and rate of combustion may be
varied within wide limits. In this way the initial pressure in the gun barrel
and the velocity of the projectile may, in a very considerable degree, be regulated.
For some purposes a mixture such as is above mentioned forms a Suitable
propelling explosive but by incorporating a small proportion of nitro-cellulose
with the base mixture of ammonium pierate and barium (or other) nitrate,
we obtain a further means of quickening combustion, and thereby regulating
the explosiveness. These two means combined give us complete control of the
explosive, so that we are able to produce an explosive suitable, not only for the
several classes of small arms, but for heavy guns as well. For example we may
proportion the nitrate to the picrate to give a certain degree of heat and regulate
the explosiveness with the required precision by means of the nitro-cellulose,
for by varying the quality or the quantity, or both quality and quantity of the
nitro cellulose. the readiness of the explosive to ignite, and the rate of combustion
after ignition may be changed.
"
For some purposes we may add some other substance as a restrainer as for
example mineral jelly, resin, etc. which serve as slowing agents to retard the
explosion.
J
L
THEO. MCKENNA.
Applicants Agent, 17 & 18, Basinghall Street, London, E.C.
COMPLETE SPECIFICATION.
Improvements in Explosives.
We. CHARLES HERBERT CURTIS. of 3. Gracechurch Street, London, E.C.,
Explosive Manufacturer, and GEORGE GUILLAUME ANDRE, of Glenlean, Argyll-
shire, Chemist, do hereby declare the nature of this invention and in what
11

page_text: manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
The object of our invention is to produce an explosive suitable for guns and
capable of being regulated in explosiveness so as to be adaptable to arms of any
calibre.
For this purpose we take as the basis of our new explosive ammonium pierate.
This salt of pieric acid is but feebly explosive, and it is wholly resolvable into
gases. Hence it is peculiarly suitable us a basis on which to form an explosive
agent of the kind that we have in view. Moreover it is safe to manipulate for
it is not very liable to be exploded by a blow or friction.
This pierate does not contain sufficient oxygen in its composition to burn
completely the carbon constituent. In this respect it is very deficient. But this
deficiency furnishes us with the opportunity of regulating the explosiveness
of a mixture of which the picrate forms the basis for by adding an oxygen
carrier in which capacity we find it very advantageous to use barium nitrate
in proper proportions, which must be determined "with reference to the duty
which the explosive is to perform, the heat and rate of combustion may be
varied within wide limits. In this way the initial pressure in the gun barrel
and the velocity of the projectile may, in a very considerable degree, be regulated.
For some purposes a mixture such as is above mentioned forms a suitable
propelling explosive but by incorporating a small proportion of nitro-cellulose
with the base mixture of ammonium pierate and barium (or other) nitrate.
we obtain a further means of quickening combustion, and thereby regulating
the explosiveness. These two means combined give us complete control of the
explosive so that we are able to produer an explosive suitable not only for the
several classes of small arms, but for heavy guns as well. For example we may
proportion the nitrate to the pierate to give a certain degree of heat and regulate
the explosiveness with the required precision by means of the nitro-cellulose,
for by varying the quality or the quantity, or both quality and quantity of the
nitro cellulose, the readiness of the explosive in ignite, and the rate of combustion
after ignition. may be changed and the explosive standardised and adapted to
various duties.
For some purposes we add some other substance as a "restrainer" as for
example mineral jelly, resin dc., which serve as slowing agents to retard the
explosion.
The principle upon which we proceed in adapting our new explosive to the work
which it has to perform may be explained as follows:-
When for example the proportion of barium nitrate is about 0.20 to 1 of pierate
the carbon in the latter is burned to C.0. As we increase the proportion of
nitrate more and more of the C.0. is burned to C., till we reach about 1.24 to 1.
when the whole of the 0.0. will be burned to 0.0. The successive additions of
nitrate serve to raise the temperature of combustion and thereby to increase the
pressure of the gases and to quicken combustion. We have here a means of
regulating the rate of combustion and the pressure of the resulting gases.
The proportion of barium nitrate suitable for the small bore military riles
now in use lies between 0.70 and 0.80-say 0.75-to 1 of picrate. For shot guns
we prefer about 1.20 nitrate to 1 picrate.
To quicken ignition we may substitute potassium nitrate for a small portion
of the barium nitrate. The following are the proportions we find most suit-
able:
Ammonium Picrate
Rifle Powder.
Nitrate
{Potassium Nitrate-
1.00
0.701
0.05
Shot Gun Powder.
Ammonium Picrate
1.00
Barium Nitrate
1.05
Potassium Nitrate
0.15
For the purnose of maintaining a given heat of combustion and at the same

page_text: The proportion as well as the quality of the gun cotton may of course be varied
to suit requirements.
This last described powder granulated to a degree of fineness about equal to
that known as No. 6 for black gunpowder" is suitable for use in military small
bore rifles, such as the 308 Lee-Metford, the Mannlicher, the Mauser, etcetera,
aud. taking it as a starting point, the powder maker will be able by the aid
if the indications hereinbefore given to modify its composition so as to adapt
it to use with any other class of gun. It is of course impossible to lay down
in general terms the exact proportions that will meet every individual case, and
the determination of the best proportions of the ingredients named for a particular
powder must of course he left to the powder maker and by him ascertained by
methods of trial in common use for that purpose. It will be found however
that a wide range of standardised and accurately graded powders can be produced
by the employment of our method of compounding the explosive.
The ingredients are first thoroughly mixed together and then incorporated
under edge runners, or other similar means, with a small proportion--from 5 to S
per cent of water. The compound is then pressed into thin cakes and granu-
lated in the usual way for fine grain powder. For big guns it may be pressed
into cakes. perforated or otherwise as required. It will of course be understood
that the rate of combustion will vary with the degree of compression given in
the press. This is a further and a well known means for regulating the rate of
combustion.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :—
1. The herein before described method of manufacturing an explosive suitable
for guns having ammonium pierate for its basis.
2. A rifle powder compounded substantially as herein before described from
ammonium picrate. barium nitrate and potassium nitrate.
3. A shot gun powder compounded substantially as herein before described from
ammonium pierate, barium nitrate and potassium nitrate in the proportions
indicated.
4. A powder suitable for guns compounded substantially as herein before
described from ammonium picrate, barium nitrate. potassium nitrate and gun
cotton in the adjusted proportions indicated.
5. The manufacture by the method herein before described of a range of
standardised and graded powders having ammonium pierate as a basis and
adapted by the means herein indicated to use with various kinds of guns.
Dated the 27th day of February 1900.
THEO.
MCKENNA.
17 & 18, Basinghall Street, London, E.C., Agent for Applicants.