Year: 1888

page_text: I, EUGÈNE TURPIN of 18, Avenue Menelotte, Colombes, (Seine) France, Chemist,
do hereby declare the nature of this invention to be as follows:-
My Invention relates to an improved smokeless powder for fire-arms.
Since the discovery of gun cotton, many attempts have been made to employ it for
charging fire arms, but whether loose or compressed its ignition under pressure is too
rapid, producing a detonation sufficient to burst the fire arm. After many experiments
in this direction, 1 have found that by rendering the gun cotton sufficiently compact
the rate of combustion may be easily regulated as well as the initial pressures
developed at the moment of combustion. In this manner, powders may be obtained
capable of producing very high velocities and very flat trajectories. Pure celluloid
for example, which is composed of gun cotton and camphor burns even too slowly for
use in fire arms the proportion of camphor being too great in the absence of any
oxidizing agent to effect its combustion, while the gun cotton itself has not the
necessary amount of oxygen to ensure its complete combustion, so that celluloid
cannot be burnt in a closed chamber except it be previously raised to a high
temperature.
I have found that a very good powder may be made as follows;-Gun cotton in
pulp is dissolved to saturation in sulphuric or acetic ether of a density of from about
fifty two to fifty six centesimal degrees, and the resulting paste spread upon plates
having raised edges or trays, and allowed to dry in the open air or in a stove with
condenser for recovering a portion of the ether employed. The layer of gun cotton
when sufficiently dry is then rolled or passed through a burnishing press, while
moistened with ether in order to reduce it to the desired thickness. The sheets thus
obtained, when perfectly dry, are then cut up into strips in a machine similar to that
for cutting up tobacco, and then again cut crosswise, so as to form small cubes or
grains of powder.
The smaller the grains, the more rapid will be the combustion and the greater the
nitial pressure. If the powder thus obtained is too quick burning, a slower burning

page_text: powder may be prepared as follows;-Dissolve in a small portion of ether at a density
of from 52° to 56° as before, a certain quantity of camphor (from two to ten per cent.
of the weight of the powder employed) and then dissolve the gun cotton to saturation
in ether which is added a little at a time as necessary. When completely dissolved the
whole is to be kneaded under edge runners or between rollers with the addition at
same time of six or seven times the weight of the camphor employed of an oxidising
agent, such as nitrates chlorates oxides etc., but preferably barium nitrate or chlorate
which produce but little smoke and serve to burn the camphor contained in the mixture.
The above proportions may be increased to suit the rate of combustion desired. The
mixture when sufficiently dry is rolled while heated, to from 80° to 100° C. or moistened
with ether as above described, and then cut up into strips and grains as before.
The dough or paste may also be obtained by mixing the camphor with the gun
cotton in pulp and subjecting to hydraulic pressure in a cylinder steam heated at the
upper part and cooled at the lower part, as in the manufacture of celluloid. The mass
thus obtained is then softened in ether at 52° to 56° and kneaded in a closed mill
during which operation the necessary oxidising agent may be added after which the
mass is rolled to thickness as before described and finally cut up to granular form.
Variable proportions of nitro benzine, nitro toluene, paraffin, etc; may be added to
the above mixtures in order to still further retard the combustion or to keep the
material in a softer condition. Or, without adding oxidising agents a portion of the
camphor may be withdrawn by allowing the compressed mass to remain immersed in
ether, after which it is rolled and cut up as before.
By these processes, powders may be obtained adapted to suit various requirements
and having various rates of combustion and pressures suited to the different kinds of
fire-arins from small arms to artillery, by varying the proportions of the above named
ingredients.
E. TURPIN.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: I, Eugène TurpiN, of 18, Avenue Menelotte, Colombes, (Seine) France, Chemist,
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:
My Invention relates to an improved smokeless powder for firearms.
Many attempts have been made to employ gun-cotton for charging fire-arms, but
whether, loose or compressed (even if coated with paraffine or camphor) its inflammation
under pressure is so rapid owing to the penetration of the flame through the fibres
and mass as to often produce a detonation and generate such high pressure as to burst
the fire-arm.
I have found that if the gun cotton when more or less nitrated be brought to a
compact condition such that the rapid ignition of the entire mass is prevented and
that on the contrary its combustion proceeds uniformly from the exterior to the centre
of the grains of powder whatever may be their size, the rate of combustion as well as
the initial pressures developed at the moment of combustion may be easily regulated
by varying the size of the grains.
In this manner, powders of various kinds may be produced capable of imparting
very high velocities and very low trajectories with comparatively low pressures and
devoid of shattering properties. Pure celluloid, for example, which is composed of
gun cotton and camphor burns slowly when unconfined owing to its compactness, and
slower still, or not at all, in a closed vessel. It is therefore useless for firearms. As
the proportion of camphor is excessive, in the absence of any oxidizing agent to effect
its combustion, and as the gun cotton itself does not contain all the oxygen necessary
for its complete combustion, celluloid therefore cannot be burnt in a closed vessel
except it be previously raised to a high temperature and perhaps not then.
I have found that a very good powder may be made as follows:-In a hermetically
closed vessel I dissolve gun cotton more or less nitrated either in the form of pulp
or otherwise or a mixture of various known kinds of gun cotton in any solvent
suited to the kind of gun cotton employed, such as nitro-benzine and other nitro-
bodies of the aromatic series, aniline, aldehydes, amido-compounds of various kinds,
acetone, sulphuric, nitric, acetic, and other ethers. Ammonia in solution in sulphuric
or other ether, acetone in solution in sulphuric or other ether, and mixtures of ethers
of any kind which I term composite ethers holding in solution from 25% to 50% of
one or more of the compound above specified, are suitable for dissolving gun cotton
more or less nitrated, even that which is the least soluble in ordinary ether whether
pure or mixed with alcohol.
A very good solvent for the most highly nitrated gun cotton is obtained with

page_text: ammonia in solution in sulphuric ether of a density of 0.750 about, or by dissolving
25% to 30% of acetone in 75% to 70% in volume of sulphuric ether of a density
of 0.750. Acetic ether for dissolving the most highly nitrated gun cotton, must be
pure and its price is too high. Ammonia in too great a quantity, or acetone employed
alone or in too large a quantity in the ether, renders the final product comparatively
brittle and friable after desiccation. Ammonia reduces tri-nitro-gun cotton and forms
an amido-compound.
One litre of the composite ether above specified will dissolve 250 grammes of the
most highly nitrated gun cotton (trinitro gun cotton for example) reduced to pulp
but thoroughly dry. These proportions may however be varied according to the
consistency of the paste required. A good paste more or less thick, according to the
quantity of ether, may be made by dissolving 100 grammes of the least nitrated
(soluble) gun cotton in one litre of sulphuric or other ether (either simple or compound)
and afterwards adding 150 grammes of well-dried tri-nitro-gun cotton in pulp and
thoroughly mixing the whole by any suitable means. The tri-nitro (or so-called
insoluble) gun-cotton is in great part soluble in a solution of soluble gun cotton
in ordinary sulphuric ether of a density of about 0.750°. When the paste has
been prepared in one of the ways above specified, it is spread by machines similar
to those employed for waterproofing fabrics with caoutchouc or by means of a hopper
running on rails upon a table upon which the paste is expressed from the hopper
upon a tray; or the tray may be placed upon an endless travelling web of wire-
gauze or other material moving beneath a stationary hopper, or any other mechanical
or manual means may be employed for forming a sheet of any desired thickness.
The layer of paste thus obtained is exposed to the action of a current of hot air of
suitable temperature, and then rolled so as to equalize its thickness by means of one
or more rollers of metal or other material which may either be heated or not and
moistened or not with ether, etc., to prevent adhesion, the tray or table being provided
with raised edges, or the rollers with end flanges, of such depth as, in all cases, to
ensure the layer of paste having a thickness about three times that which the sheet is
to ultimately possess, this extra thickuess being necessary to compensate for shrinkage
produced by evaporation of the solvent and to permit of the sheet being sufficiently
rolled to render it thoroughly compact. The paste, after being spread in sheets of
the desired dimensions, is then dried either in the open air or in a stove provided with
a refrigerating jacket for recovering, by condensation,. a portion of the solvent
employed.
When the sheets of gun cotton thus prepared are nearly, but not completely, dry
they are passed, either separately or several together, through an ordinary roller or
calendering press or if of considerable thickness they are compressed in an hydraulic
or other press, to the desired thickness and density, the operation being facilitated by
softening the sheets with ether of a density of about 0.700. The sheets thus obtained
are then cut up into strips in a machine such as used for cutting paper or pasteboard,
the width of the strips corresponding to the thickness of the sheets, and then again
cut cross-wise, so as to form small cubes or grains of powder. Grains of small
size may also be produced by rasping or milling tools, or by circular or other saws
juxtaposed. The powder thus obtained is sifted in order to sort the different sizes of
grains.
The smaller the grains the greater will be the rate of combustion and the higher
consequently will be the initial pressure and the velocity of the projectiles, for charges
of equal amount. A more perfect combustion may be obtained with smaller grains,
and thus with a smaller charge the same pressure and velocity may be obtained as
with a larger charge composed of larger grains, for in the latter case a portion of the
charge is blown out of the gun before it has had time to be completely consumed. The
size of the grains should increase proportionately to that of the calibre of the gun.
For artillery, the explosive material need not be granulated, but may be used in the
form of strips. By this means the rate of combustion may be slightly retarded as the
surface of ignition is less for a strip of a given weight than for the same strip cut up
into cubes or prisms.

page_text: If powder of a grain equal to 1 cubic millimetre in volume be best suited for a
calibre of 10 millimetres (which appears to be approximately correct) the size of
grain or the width and thickness of strips (in the case of artillery) may be deduced
from this formula for each calibre so as to obtain proportionate pressures and
velocities, these pressures and velocities being variable for each calibre by varying
the size of the grains and weight of the charge.
Thus, if the linear dimension of the cube or grain should be one-tenth of the calibre
of the arm for which it is intended, a fire arm of a calibre of 7 millimetres would
require a grain having a linear dimension of .75 millimetre, and one of eight milli-
metres, calibre a grain of .8 millimetre. A gun of two hundred millimetres calibre
would require a grain of twenty millimetres, or preferably strips of twenty millimetres
in width and thickness and of the same length as the chamber of the gun. The weight
of the charge would in this case, depend on the pressure and velocity desired and
would generally be fifty per cent. of the charge of ordinary black gunpowder whilst
giving a higher velocity.
The grains instead of being cubes may be made of various prismatic forms having
the same volume, by reducing the thickness and increasing the breadth.
If the powder is too quick-burning for some purposes such as for congreve rockets,
rocket lines, etc., the combustion may be chemically retarded in the following
manner: Dissolve in a portion of ether, either pure or of the composition herein-
before described, a certain quantity of camphor (from 2% to 10% of the weight of
the powder employed) and then dissolve the gun cotton in the manner before described.
When completely dissolved, the whole is to be kneaded under edge runners or between
rollers with the addition at same time of six or seven times the weight of the camphor
employed of an oxidising agent such as nitrates, chlorates, oxides, etc., but preferably
barium nitrate or chlorate which produce but little smoke and serve to burn the
camphor contained in the mixture. The above proportions may be increased to suit
the rate of combustion desired. The mixture when sufficiently dry is hot rolled at
from 80° to 100° C. or softened with ether and cut up into strips and grains, as
before.
The dough or paste may also be made by mixing the camphor, with the gun cotton
in pulp and pressing by hydraulic pressure in a cylinder steam heated at the upper
part and cooled at the lower part, as in the manufacture of celluloid. The mass thus
obtained is then softened in ether of 0.720° to 0.750° sp: gr and kneaded in a closed
mill during which operation the necessary oxidising agent may be added, after which
the mass is rolled to thickness and finally cut up to granular form, as before
described.
Variable proportions of nitro-benzene, nitro-toluene, paraffine, etc., may be added
to the above mixtures in order to still further retard the combustion or to keep the
material in a softer condition. Or, instead of adding oxidising agents, a portion of
the camphor may be withdrawn by steeping the compressed mass in ether after which
it is rolled and cut up, as before.
By these processes, powders may be obtained adapted to suit all requirements and
having various rates of combustion and pressures suited to the different kinds of fire
arms, from small arms to artillery by varying the proportions of the above mentioned
ingredients.
Having now particularly described and ascertained the nature of. the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:
1st. The manufacture of a smokeless powder for firearms by dissolving gun cotton
in a composite ether or equivalent solvent with or without an oxidising agent and
afterwards strongly compressing the mass, as and for the purpose specified.
2nd. The employment, for the manufacture of a smokeless powder from gun cotton,
of solvents composed of ether holding in solution, ammonia, acetone, nitro-compounds
of the aromatic series, as described, and in the manner specified.

page_text: 3rd. The processes of manufacture which consist in spreading the material
prepared as herein specified, equally upon a fixed or travelling surface, then rolling or
pressing it, and afterwards dividing or cutting up the compressed material into strips
or by cross-cutting into grains, or reducing the mass by means of saws or cutters, all
substantially as hereinbefore described.
E. TURPIN.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.