Improvements in the Manufacture of Gunpowder.
Year: 1891

page_text: Date of Application, 4th Nov., 1891
Complete Specification Left, 3rd Aug., 1892-Accepted, 4th Nov., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Gunpowder.
We, CHARLES HERBERT CURTIS of 74 Lombard Street in the City of London
Gunpowder Manufacturer and GEORGE GUILLAUME ANDRÉ of Havelock
Cottage, Dorking in the County of Surrey Civil Engineer do hereby declare the
nature of this invention to be as follows:-
It has been a matter of common knowledge among chemists ever since the
discovery of gun-cotton in 1845 that nitro-cellulose is soluble in certain ethers.
This solubility affords the readiest and the most frequently used test of the degree
of nitration effected in the cellulose. Thus cotton, for example, nitrated in the
second degree and known as di-nitro-cellulose, is soluble in ordinary (sulphuric)
ether to which a small proportion of alcohol has been added; while cotton nitrated
in the third degree, and known as tri-nitro-cellulose, is not soluble in that substance.
But this same tri-nitro-cellulose, as well as the lower grade (di-nitro-cellulose) is
soluble in acetic ether and in acetone. Several inventors have of late utilized
the solvent property of acetic ether and acetone to completely dissolve nitro-
cellulose for the purpose of rendering the latter fit for use as gunpowder; their
method is to reduce the mass of nitro-cellulose and solvent to a thick homogeneous
paste by macerating and kneading it so as to completely destroy the fibrous nature
of the cellulose, and then to produce from this paste rods wires strips or granules
by means of special machinery and apparatus. We do not claim any of these
things but proceed otherwise in our method of manufacturing gunpowder. We
first mix with the gun cotton (tri-nitro-cellulose) a small proportion, say from
6 to 16 per cent. of di-nitro-cellulose, or we produce a gun cotton containing the
requisite proportion of cotton nitrated in the second degree, and then we manu-
facture this nitro cotton while in the wet and therefore inexplosive state, into
granules or pellets. So made, these granules or pellets are soft and easily friable,
and when dried they become violently explosive. In this state they are useless as
gunpowder. We next treat these dried (or it may be partially dried) granules
with the solvent capable of dissolving only the di-nitro-cellulose. The latter when
dissolved forms a cement strong and inflammable, but only feebly explosive. This
cement hardens on the evaporation of the solvent and binds firmly together the
undissolved fibres of guncotton. There is, it will be observed, no mere coating
of the granules in this case and no mere hardening of the surface only; but all
the fibres throughout the mass of the granule are strongly cemented together so
cannot be broken up
that the said granule becomes very hard and so strong that
by rubbing between the fingers. This effect is very different from that which is
brought about by the use of collodion to harden the granules. In the latter case
the granules are friable or may be easily rubbed to powder by the fingers.
Another and a very important effect of cementing together the fibres of gun
cotton of which the granule is composed in the way we have described is to
moderate their explosiveness. By simply varying the proportion of the dinitro-
cellulose within the limits already mentioned any requisite degree of explosiveness
may be obtained: the larger proportion of dissolved cotton present the slower the
rate of burning. This graduation of the rate of combustion cannot be obtained
when the whole of the explosive material is dissolved by acetic ether or acetone.
We do not limit ourselves to the method of first producing the granules or
pellets and then treating them with the solvent. We may thus treat the prepared
nitro-cellulose with the solvent and afterwards, but before the solvent has evaporated,
make it into pellets.
We may to retard ignition, dissolve the whole surface of the granules or pellets

page_text: manufactured in the way described by sprinkling these granules or pellets with
acetic ether or acetone.
Nitro-glycerine may be combined with the nitro-cellulose by dissolving the
former in the solvent used for the latter.
Dated this 4th day of November 1891.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.
COMPLETE SPECIFICATION.
Improvemente in the Manufacture of Gunpowder.
We, CHARLES HERBERT CURTIS of 74 Lombard Street in the City of London
Gunpowder Manufacturer and GEORGE GUILLAUME ANDRÉ of Glenlean,
Sandbank by Greenock in the County of Argyle Civil Engineer and Gunpowder
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:-
It has been a matter of common knowledge among chemists ever since the
discovery of gun-cotton in 1845 that nitro-cellulose is soluble in certain ethers.
This solubility affords the readiest and the most frequently used test of the degree
of nitration effected in the cellulose. Thus cotton for example nitrated in the
second degree and known as di-nitrocellulose is soluble in ordinary (sulphuric)
ether to which a small proportion of alcohol has been added while cotton nitrated
in the third degree and known as tri-nitrocellulose is not soluble in that substance.
But this same tri-nitrocellulose as well as the lower grade (di-nitrocellulose) is
soluble in acetic ether and in acetone. Several inventors have of late utilized the
solvent property of acetic ether and acetone to completely dissolve nitro-cellulose
for the purpose of rendering the latter fit for use as gunpowder. Their method is
to reduce the mass of nitro-cellulose and solvect to a thick homogeneous paste by
macerating and kneading it so as to completely destroy the fibrous nature of the
cellulose, and then to produce from this paste rods, wires, strips or granules by
means of special machinery and apparatus. We do not claim any of these things
but proceed otherwise in our method of manufacturing gunpowder. We first mix
with the guncotton (tri-nitrocellulose) a small proportion say from 6 to 16 per cent.
of di-nitrocellulose. By mixing from 6% to 16% of di-nitrocellulose with the
guncotton we mean adding that proportion to the ordinary high grade guncotton
which usually contains about 12% of the soluble grade. Thus the total proportion
will be 18 to 28 parts of the di-nitrocellulose to 88 parts of the tri-nitrocellulose.
These are the extreme limits. Or we produce a guncotton containing the requisite
proportion of cotton nitrated in the second degree and then we manufacture this
nitro cotton while in the wet and therefore inexplosive state into granules or pellets.
So made these granules or pellets are soft and casily friable and when dried they
become violently explosive. In this state they are useless as gunpowder. We
next treat these dried (or it may be partially dried) granules with the solvent
capable of dissolving only the di-nitrocellulose. The latter when partly dissolved
forms a cement strong and inflammable but only feebly explosive. This cement
hardens on the evaporation of the solvent and binds firmly together the undissolved
fibres of guncotton. There is it will be observed no mere coating of the granules
in this case, and no mere hardening of the surface only but all the fibres throughout
the mass of the granule are strongly cemented together so that the said granule
becomes very hard and so strong that it cannot be broken up by rubbing between
the fingers. This effect is very different from that which is brought about by the
use of collodion to harden the granules. In the latter case the granules are friable
and may be easily rubbed to powder by the fingers.
Another and a very important effect of cementing together the fibres of gun-
cotton of which the granule is composed in the way we have described is to

page_text: moderate their explosiveness. By simply varying the proportion of the di-
nitrocellulose within the limits already mentioned any requisite degree of
explosiveness may be obtained the Targer the proportion of partly dissolved cotton
present the slower the rate of burning. This graduation of the rate of combustion
cannot be obtained when the whole of the explosive material is dissolved by acetic
ether or acetone.
We do not limit ourselves to the method of first producing the granules or
pellets and then treating them with the solvent. We may treat the prepared
nitro-cellulose with the solvent and afterwards but before the solvent has evaporated
make it into pellets.
We may to retard ignition dissolve the whole surface of the granules or pellets
manufactured in the way described by sprinkling these granules or pellets with
acetic ether or acetone.
Nitroglycerine may be combined with the nitrocellulose by dissolving the former
in the solvent used for the latton
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
First. The application to a mixture of guncotton and dinitrocellulose of a solvent
for the latter whereby the fibres of the guncotton are cemented together for the
purpose of regulating the rate of burning of the gunpowder so made substantially
as set forth.
Second. The application of acetone or equivalent solvent of guncotton by
sprinkling therewith the granules made as firstly claimed for the purpose of
retarding the ignition.
Third. The combination of nitroglycerine with a nitrocellulose mixture made as
firstly claimed substantially as set forth.
Fourth. The manufacture of gunpowder substantially as set forth.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.