Improvements relating to the Manufacture of Explosives and to Apparatus therefor.
Year: 1888

page_text: Date of Application, 8th Nov., 1888
Complete Specification Left, 8th Aug., 1889-Accepted, 28th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements relating to the Manufacture of Explosives and to
Apparatus therefor.
1, HIRAM STEVENS MAXIM, of 53 Parliament Street, in the City of Westminster,
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
:-
My invention relates to the manufacture of explosives for use in fire-arms and for
other purposes.
The main object of my said invention is to provide an explosive which will be
smokeless or will by its combustion produce much less smoke than gunpowder, and
which when used in a fire-arm will burn slowly as compared with ordinary gun
cotton and will exert a high and continuous pressure on the projectile. My said
invention morcover comprises improved apparatus for use in the manufacture of
explosives as hereinafter set forth.
Gun-cotton has most of the elements or qualities requisito in an explosive for use
in fire-arms, that is to say, when properly prepared it is stable, very powerful,
produces but a small quantity of smoke, does not injure metallic cartridge-cases, and
is not sufficiently hygroscopic to impair its efficiency. It has nevertheless, as hitherto
manufactured, the disadvantage that it is too quick or sudden in its action. I obviate
this defect by my invention as hereinafter described.
Attempts have heretofore been made to manufacture explosives from collodion
formed by the treatment of the low grades of gun-cotton. By tho low grades 1
mean those which aro readily soluble in ether or alcohol or in a mixture of these
substances, and which do not contain a large percentage of oxygen. The low grades
of gun-cotton are unstable, do not withstand the action of sunlight, and, as they do
not contain sufficient oxygen to consume all of tho vegetable matter of which they
are composed, they produce, in burning a large quantity of smoke.
My invention relates chiefly to the manufacture of pellets, grains or other forms of
powder or explosive material from the higher grades of gun-cotton, that is to say,
tho highly explosivo grades thereof which are not soluble in ether or alcohol. To
accomplish this result, I soften or dissolve the gun-cotton in acetone, either alone or
mixed with ether or alcohol, or in ethylic acetate, or in similar liquids. I am thus
enabled, without the use of any of the low grades of gun-cotton, to make highly
explosive material which produces a very small proportion of smoke and which has
great stability.
When gun-cotton is dissolved, it forms a thick gelatinous mass which is very
Moreover the
difficult to manipulate by the means heretofore used for this purpose.
amount of liquid or solvent required, in the methods heretofore adopted, to bring the
dissolved gun-cotton to such a consistency that it can be spread out to be dried, is
very great, consequently the manufacture of explosives from gun-cotton has hitherto
been very costly.
In order to reduce the quantity of liquid or solvent required and to facilitate the
manipulation of the dissolved gun-cotton, I have devised improved apparatus
whereby only a small quantity of solvent is required so that the loss from evapora-
tion is reduced to a minimum, the facility of making the powder is much increased,
and the cost of manufacture greatly diminished.
In carrying my invention into practice, according to one method, the highly
explosive gun-cotion is first reduced to a pulp in water in a rag-engine or pulping
machine. The pulp is then thoroughly washed and dried. The dried pulp is then
placed in a strong metal cylinder provided with a piston; the air is then exhausted,
that is to say, a vacuum or partial vacuum is created in the said cylinder and the

page_text: vapours of acetone, either alone or mixed with ether or alcohol or both, are allowed
to enter the said cylinder. Every particle of air being removed from the interior of
the fibres of the cotton, the acetone vapours will penetrate to the core of every fibre
and the product will be quite free from air-bubbles, empty spaces or soft parts such
as exist in ordinary gun-cotton and into which, when the material is exploded while
closely confined, the inflamed gases are forced by the pressure developed, thus
causing the too rapid explosion of the gun cotton when detonated by fulminate of
mercury.
By my process the product is mado very dense and free from air-bubbles or
vacant spaces so that it will not yield under the enormous pressure in the gun. I
can therefore make a powder which will explode slowly enough to be used in any
description of fire-arm, the rapidity of burning or explosion depending upon the size
of the grains, the density being always at its maximum. Powder or explosive
material so formed produces very little smoke, can be manufactured cheaply, and can
be made to explode with any degree of rapidity.
The apparatus which I employ comprises a cylinder in which is fitted a piston,
the rod whereof passes through a stuffing-box in a removable or detachable cap or
cover at one end of the cylinder; the other end of this cylinder is provided with
an aperture or nozzle. The said apparatus also comprises a closed vessel for con-
taining the acetone or other solvent. This vessel is placed in a tank which is to be
filled or partly filled with hot water. Or other suitable provision is made for
evaporating the acetone or other solvent. The said vessel is connected with the
aforesaid cylinder by a pipe provided with one or more cocks as may be required.
The cylinder is also connected by a pipe with an air-pump or other apparatus for
drawing the air therefrom. When the gun-cotton has been dissolved in the said
cylinder, the latter is disconnected from the said pipes, and, by means of the said
piston, the plastic explosive material is forced out through the said aperture or
nozzle in the form of a continuous strip or thread and may be cut into small pieces
or grains. Or there may be more than one aperture in the end of the said cylinder,
so that two or more strips or threads of the said material can be formed
simultaneously.
If gun-cotton be partially gelatinized or dissolved and then pressed into very
hard sheets or cakes, it will not explode quickly but will allow the projectile to move
before an excessively high pressure is set up in the gun.
I sometimes employ a highly explosive grade of gun cotton and proceed as follows,
viz. the gun-cotton is first reduced to a pulp in a paper-pulping machine as above
described to remove any free acid that it may contain. The pulp is then moistened
with acetone and is treated until it becomes partially dissolved, with a mixture of
six parts of ether to one of alcohol. When it has been sufficiently softened it is
pressed into a solid cake or sheet and allowed to dry, or it is put into a cylinder
and squeezed in a small stream or streams through one or more fine openings.
The thread so formed is cut into any desired lengths to form the grains or other
pieces of explosive material.
The press used for forming it into sheets or cakes should be a very strong one
and the pressure on the material very high, higher than any it would ever encounter
in the gun, it may be advantageous to apply a moderate amount of beat to the
material while in the press. I prefer to subject the material to a pressure of from
20 to 40 tons per square inch. The sheet of solidified compressed cotton thus obtained
is cut up so as to form swall cubes. These cubes may have their corners rounded by
rumbling.
If it is found after this treatment, that the powder or cotton still explodes too
quickly, other substances are mixed with the cotton which will have a tendency to
diminish the rate of combustion.
Gun-cotton as hitherto manufactured, when used in a gun, explodes too suddenly
because the high pressure set up ignites the whole mass instantly by compression,
that is to say, when closely confined, the inflamed gases are forced, under the
enormous pressure developed in the gun, into the interstices and decomposition is

page_text: thus accelerated. When however it is made as above described in lumps or grains
of considerable size and in such a state of compression that no pressuro to which it
is liable to be subjected in the gun can further compress it, it can only burn from
the outside of the grains, and the explosion although quick will take long enough
to allow the projectile to move forward before the total mass is in a state of ignition.
A slight mixture of mineral wax or resinous matter or hydrocarbons combined with
some oxygen-bearing salt like nitrate of potash or soda or chlorate of potash are
sometimes added to the gun-cotton to facilitate solidification and diminish the rate of
burning.
To produce a slow burning powder, I sometimes combine with the gelatinized mass
of parily dissolved gun-cotton, a small percentage of nitrate of potash or soda, or
chlorate of potash or other oxygen-bearing salts, and in some instances, a larger
percentage of chlorate of potash and about one per cent. of paraffin wax.
According to another method or process, the paper pulp is formed into thick
sheets and is then cut into small squares and treated with ether and alcohol, or
with ether, alcohol and acetone until it is partly dissolved, and is then allowed to
dry.
To obtain very large grains to be used in the larger forms of guns, I prefer to
place the gun-cotton or the pulp in a receiver and to exhaust the air therefrom and
then allow the vapours of the solvents to enter until the mass becomes to a certain
degree sticky, or partly dissolved; then, without admitting any air, I compress the
mass and solidify it. Large and solid pieces may thus be formed which are quite
free from air bubbles.
According to another modification of my process, the low and soluble grades of
gun-cotton are dissolved with ether thus forming collodion; the collodion is then
intimately combined with gun-cotton which is of a highly explosive nature and
which is insoluble in ether; the collodion of the low grade being sufficient to cause
the gun-cotton of high grade to adhere in a solid mass. As the low grades have
less oxygen than the high grades, I find it advantageous in this case, to employ
chlorate of potash to supply additional oxygen.
The cotton may if desired be first made into paper and the paper then partly
gelatinized and pressed; I find it more advantageous, however, to first treat the
cotton and then reduce it to pulp, this being the most effectual method of removing
the free acid.
The product formed by the compression and drying of the mixtures before mentioned
is very hard, resembling born; it does not injure metallic cartridge-cases, is not
sufficiently bydroscopic to impair its effectiveness, is very powerful, and it burns
much slower than ordinary gun-cotton, while it gives very little smoke and produces
a high pressure. It is, therefore well adapted for use in cases where the absence of
smoke is desirable.
Dated this 8th day of November 1888
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements relating to the Manufacture of Explosives and to
Apparatus therefor.
I, HIRAM STEVENS MAXIM, of Crayford Works, Crayford, in the County of Kent,
and 53 Parliament Street, in the City of Westminster, Mechanical Engineer, 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 the manufacture of explosives for use in fire-arms and for
other purposes, and to apparatus for use in such manufacture.
The main object of my said invention is to provide in a more efficient manner than

page_text: heretofore, for the production from gun-cotton of an explosive which will be com-
paratively smokeless or will by its combustion produce much less smoke than gun-
powder, and which, when used in a fire-arm, will burn slowly as compared with
ordinary gun-cotton and will exert a high and continuous pressure on the projectile.
My said invention comprises improved methods or processes whereby I am enabled
to economically and advantageously manufacture pellets, grains or other pieces of
explosive material from the higher grades of gun-cotton, that is to say, the highly
explosive grades thereof which are not soluble in ether or alcohol.
When gun-cotton is dissolved, it forms a thick gelatinous mass which is very
difficult to manipulate by the means heretofore generally used for this purpose.
Moreover in the methods of manufacture heretofore adopted, a very large quantity
of the solvent is required to bring the gun-cotton to such a consistency that it can
be spread out to be dried, consequently the manufacture of explosives from gun-cotton
has hitherto been very costly.
By my invention the quantity of solvent required is greatly diminished, the loss of
such solvent by evaporation is reduced to a minimum, the facility of manipulating
the dissolved gun-cotton and of making the explosive material is much increased,
and the cost of manufacture thus greatly diminished, as compared with the methods
of manufacture heretofore adopted.
An important feature of my said invention is the treatment of the gun-cotton in
a chamber or receiver from which air is exhausted.
Another important feature of my said invention consists in subjecting the gun-
cotton to the action of a solvent in the form of vapour instead of in a liquid state
as heretofore. For this purpose I prefer to use, as the solvent, acetone or ethylic
acetate, either alone or mixed with ether or alcohol or with both of these substances.
I can, however, employ other solvents if desired.
The
In carrying my said invention into practice, according to one method or process,
the highly explosive gun-cotton is treated as follows, viz. :-It is first reduced to
pulp in water in a rag-engine or pulping-machine or other suitable machine, and
then thoroughly washed and dried. The dried pulp is then placed in a strong
metal cylinder or chamber and the air is exhausted from the said cylinder or
chamber, that is to say, a vacuum or partial vacuum is created therein.
vaporized solvent consisting of acetone, either alone or mixed with ether or alcohol
or with both of these substances, is then allowed to enter, or is forced into the said
cylinder or chamber. The air being entirely removed from the interior of the fibres
of the cotton, the vaporized solvent will penetrate to the core of every fibre and the
product will be entirely free from air-bubbles and from empty spaces or interstices
such as exist in ordinary gun-cotton and into which, when the material is exploded
while closely confined, the inflamed gases are liable to be forced by the pressure
developed, thus causing too rapid explosion or detonation of the gun-cotton. After
the treatment of the gun-cotton with the vaporized solvent as above described, the
explosive material thus produced is preferably subjected to a very high degree of
compression, and is then, if desired, cut or divided into pellets, grains or other pieces
of any suitable dimensions.
In the accompanying drawings
Figure 1 is a plan, and
Figure 2 a vertical longitudinal section on the line, x, Figure 1, illustrating one
form of my improved apparatus for the manufacture of explosive material.
Figure 3 is a vertical central section showing a modification of part of the said
apparatus.
Figure 4 is a perspective view illustrating a method of cutting or dividing the
explosive material into small pieces or grains.
Like letters indicate corresponding parts throughout the drawings.
A is the cylinder in which the gun-cotton is to be treated. B is a closed vessel
for containing the acetone or other solvent. is a tank in which the said vessel B
is placed and which is to be filled, or partly filled with water. Suitable provision
is made for heating the water, either before or after its introduction into the said

page_text: tank, for the purpose of vaporizing the said solvent. Other suitable means may,
however, be employed, if desired, for vaporizing the acetone or other solvent.
In the apparatus shown in Figures 1 and 2, the cylinder A is provided with a
removable or detachable cap or cover a at one end thereof, and with a piston b, the
The
rod of which passes through a stuffing-box a' in the said cap or cover a.
other end of the cylinder A is provided with a nozzle c having a cock or valve c¹.
The vessel B is formed with a suitable aperture for the introduction of the solvent,
which aperture is closed by a plug B. The cylinder A is connected with the
vessel B by a pipe d provided with a cock or valve d'. The cylinder A is also
connected, by the piped and by another pipe e provided with a cock or valve e
with an air-pump or other apparatus (not shown in the drawing) for pumping or
exhausting the air from the said cylinder.
The manufacture of explosive material is carried on by means of the above
described apparatus as follows, viz. :-The cocks or valves being all closed, the cap or
cover is removed from the cylinder A together with the piston b; the cylinder A
is then filled with the aforesaid dried pulp, or with gun-cotton otherwise suitably
prepared, and, the cap or cover a and piston b being replaced, the said cap or cover
is screwed tightly upon the end of the said cylinder, the piston 6 then being in the
position indicated in the drawing. The cocks cand e¹are then opened and a vacuum,
or partial vacuum, is created in the cylinder A by means of the aforesaid air-
pump or other exhausting apparatus. The cock or valve e' is then closed and the
cock or valve d opened, so that the vaporized solvent is forced into the cylinder A.
When the gun-cotton has been gelatinized or dissolved in the said cylinder, the
latter is disconnected from the pipe d, and, by means of a suitable hydraulic or
other press acting upon the piston b, the plastic explosive material is forced out
through the nozzle c in the form of a continuous strip or thread, and may then be
cut into small pieces or grains. There may, if desired, be more than one aperture in
the said nozzle, so that two or more strips or threads of the said material will be
formed simultaneously.
The cylinder A shown in Figure 3 is closed at its lower end by means of a remov-
able or detachable cover or baso a having one or more apertures a² through which the
explosive material will be forced in the form of strips or threads. The piston b
consists of two parts or discs between which is placed a cup-leather b². The said
discs are arranged as shown, or otherwise, so that they may be adjusted in such a
manner as to clamp or squeeze the said cup-leather between them and thus make the
same fit tightly within the cylinder, so that the said piston cannot be moved by the
pressure of the atmosphere when a vacuum is formed in the cylinder. The said
cylinder A is provided with a nozzle c for connection with the pipe d, the said nozzle
being provided with a cock or valve c' as above described.
When the gun-cotton has been treated with the vaporized solvent in this cylinder
in the manner above described, the said cylinder is disconnected from the pipe d and
placed under a suitable press, whereby the piston is moved downward and the
explosive material thus forced out through the apertures a³. The mass of com-
pressed material remaining in the cover or base a after this operation will be
sufficiently stiff or solid to prevent the entrance of air into the cylinder when a
vacuum is formed therein during the treatment of a fresh quantity of gun-cotton.
I prefer to employ three or more cylinders such as that shown in Figure 3, so
that, while one cylinder is under the press, another cylinder can be used for the
treatment of gun-cotton with the solvent as above set forth, and a third cylinder can
at the same time be charged with gun-cotton.
According to another method or process, I manufacture explosive material by
gelatinizing or dissolving gun-cotton as above described, and then compressing it
and thus forming it into very hard sheets or cakes, which are cut or divided into
pieces or grains of any desired size. For this purpose a suitable quantity of a high
grade or highly explosive gun-cotton is reduced pulp in a paper-pulping machine
or rag-engine or other suitable machine, as above described, to remove any free acid
that it may contain and is then dried. The dried pulp is then moistened with

page_text: acetone and subjected to the action of a mixture of six parts of ether to one of
alcohol until it is partially dissolved. When it has thus been made sufficiently plastic
it is compressed into a solid cake or sheet and allowed to dry. The sheet of solidified
or compressed gun-cotton thus obtained is cut up into small cubes or pellets. These
cubes or pellets may have their corners rounded by rumbling or in any other
convenient manner.
The press used for forming the dissolved or partially dissolved, gun-cotton into
sheets, cakes, strips, throads or other pieces should be a very strong one and the
pressure applied to the material should be very high. I find it advantageous to
subject the gelatinized gun-cotton to a pressure higher than any it will ever be likely
to encounter in the gun. For example I subject it to a pressure of from 20 to
40 tons per square inch. It may be advantageous to apply a moderate amount of
heat to the material while in the press.
Gun-cotton as hitherto manufactured, when used in a gun, explodes too suddenly,
because the high pressure set up in the chamber of the gun forces the inflamed gases
into the interstices of the explosive material, thus causing instant ignition of the
entire mass thereof. When, however, it is made as above described in lumps or
grains of considerable size and in such a state of compression that no pressure to
which it is liable to be subjected in the gun can further compress it, it can only
burn from the outside of the grains, and the explosion although quick will be
sufficiently retarded to allow the projectile to move forward before the entire mass
is in a state of ignition.
The gun-cotton may, if desired, be first made into paper and then partially
gelatinized and compressed. In some instances, the gun-cotton pulp is formed into
sheets of any desired thickness, which are then cut into small cubes or pellets, and
treated with ether and alcohol or with ether, alcohol and acetone or other suitable
solvent until the gun-cotton is partially dissolved, and are then allowed to dry.
To obtain very large cubes, pellets or other pieces for use in heavy guns or
ordnance, I sometimes proceed as follows, that is to say, I place the gun-cotton
pulp in a suitably shaped receiver and exhaust the air therefrom and then allow the
vaporized solvent to enter the said receiver and act upon the mass until the same
becomes to a certain degree sticky, or partially dissolved; then, without admitting
any air, I compress the mass and solidify it and withdraw it as a whole from the
said receiver. Large and solid pieces may thus be formed which are quite free from
air-bubbles. Blocks of the explosive material thus formed can, if desired, be con-
veniently cut or divided into small pieces or grains in any suitable manner.
example, a block J, Figure 4, of the explosive material, of rectangular form in
transverse section, is produced as above described, and is subjected to the action of
knives or cutters whereby a series of cuts or incisions are first formed in the said
block and then a series of cuts or incisions at right angles to the incisions ; ; the
square rods thus formed are then subjected to the action of a transverse cutter
whereby they are divided into small cubes or grains.
For
If the explosive material manufactured as above described is found to still explode
too quickly for the purpose for which it is required, I mix with the gun-cotton any
suitable substance or substances which will have a tendency to diminish the rate of
combustion thereof.
A mixture of mineral wax or resinous matter or of a hydrocarbon with some
oxygen-bearing salt such as nitrate of potash or of soda, or chlorate of potash, is
sometimes added to, or combined with, the gun-cotton to facilitate solidification and
diminish the rate of burning. In some instances, 1 combine, with the gelatinized
mass of partially dissolved gun-cotton, a small percentage of nitrate of potash or of
soda, or chlorate of potash or other oxygen-bearing salts, and, in other instances, a
larger percentage of chlorate of potash, and about one per cent. of paraffine-wax.
The explosive material manufactured by the improved process above described,
being very dense and free from air-bubbles or empty spaces or interstices, will not
yield under the enormous pressure to which it is subjected in the gun. I can,
therefore, make an explosive which will explode slowly enough to be used in any

page_text: description of fire-arm; moreover I can vary the rapidity of the burning or explosion
of the material by varying the size of the grains thereof.
The product formed by the methods of manufacture above described is very hard,
resembling horn; it does not injure metallic cartridge-cases; is not sufficiently
hygroscopic to impair its effectiveness; is very powerful, and burns much slower
than ordinary gun-cotton; while it gives very little smoke and produces a high
pressure it is, therefore, well adapted for use in cases where the qualities above
named and especially the absence of smoke are desirable.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 wish it understood that
I claim :-
First. The treatment of gun-cotton with a solvent in a chamber from which air is
exhausted, for the purpose above specified.
Second. In the treatment of gun-cotton, the employment of acetone, ethylic acetate
or other solvent in a vaporized condition, for the purpose above specified.
Third. The herein described method of softening or dissolving gun-cotton, consisting
in treating the same, in a chamber from which air is exhausted, with vaporized
acetone, ethylic acetate or other solvent.
Fourth. The manufacture of explosive material by first reducing gun-cotton to
pulp, washing and drying the same or otherwise suitably preparing it, and then
treating it, in a chamber from which air is exhausted, with vaporized acotone, ethylic
acetate or other solvent, and subjecting it to pressure, substantially as, and for tho
purposes, set forth.
Fifth. In the manufacture of explosive material from gun-cotion, subjecting the
softened or dissolved or partially dissolved gun-cotton to a pressure higher than that
to which it is liable to be subjected in a fire-arm, for the purposes above specified.
Sixth. The method of manufacturing explosive material, consisting in reducing
gun-cotton to pulp, moistening the said pulp with acetone and softening or partially
dissolving it by means of ether and alcohol and then compressing it, substantially as,
and for the purposes, set forth.
Seventh. The cylinder provided with the removable or detachable cap or cover,
the piston and one or more discharge apertures and adapted to be connected with
an air-pump or other exhausting apparatus and with apparatus for the supply of
vaporized acetone, ethylic acetate or other solvent, substantially as, and for the
purposes, set forth.
Eighth. The improved apparatus constructed and arranged substantially as described
with reference to Figures 1 and 2 of the drawings, for the purposes specified.
Ninth. In the manufacture of explosive material from gun-cotton, the combination,
with the softened or dissolved or partially dissolved gun-cotton, of a mixture of wax
or resinous matter and nitrate of potash or other oxygen-bearing salt, for the
purposes above specified.
Tenth. The method of manufacturing explosive material, consisting in first reducing
gun-cotton to pulp, forming the said pulp into sheets and dividing the said sheets
into cubes or other pieces, and then partially dissolving the said pieces and drying
them, substantially as set forth.
Eleventh. The modification of my improved process wherein I form a cube, pellet
or other piece of the explosive material in a receiver from which air is exhausted, and,
after compressing and solidifying the mass, withdraw it as a whole from the said
receiver, substantially as set forth.
HIRAM S. MAXIM.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.