Improvements in or connected with the Treatment of Explosives.
Year: 1898

page_text: Improvements in or connected with the Treatment of Explosives.
65
or
I, FREDERICK WILLIAM JONES, of Barwick, Ware, in the County of Hertford,
Chemist, do hereby declare the nature of this invention to be as follows: —
The present invention relates to the treatment of explosives, and has for its
object to moderate and regulate the combustion of explosive charges, and is
more especially applicable to granulated "gelatinized dissolved" powders,
for use in guns of all calibres.
* dis-
It is well understood that the gunpowders known as "gelatinized" or
solved," under normal conditions burn only on the outside of the grains, and
therefore the evolution of the gases from a charge, or its combustion, is a
function of the superfices of the grains. Obviously by varying the size, shape,
and perforations of the grains, the rate of combustion is varied to any degree;
from the initial ignition to complete combustion. The variation in shape and
size of grains or granulation, is the method now in vogue, and applied to all
gelatinized explosive substances to fit them for guns of different calibres, the
rate of combustion of the explosive substance being determined by its physical
and chemical nature in well understood ways i.e., by the nature of the solvent
and the method of applying the same, and the explosive ingredients and moderators.
With present-day gunpowders, the grains of a charge are all ignited before the
projectile moves any material distance, therefore the initial burning surfaces
of a charge determine the initial pressure, so that the aim of manufacturers is
to make the initial burning area, the smallest possible, combined with a minimum
thickness of grain, which will cause the grains to be consumed, as the projectile
leaves the barrel, therefore practically the whole of the grains should be ignited
by the primer, to use grains presenting a minimum superficies.
In gunpowders as at present manufactured, the ignition of the whole charge
in a small capacity causes high initial pressure, and the weight of the charge
and the velocity of the projectile is thus limited by gun construction.
To overcome this defect the charge is air-spaced, or the grains are multi-
perforated in various manners.
The granulation and the variation of the physical and chemical nature of the
explosive substances, are the present means manufacturers use to make gun-
powders for guns of all calibres, hitherto it has never been proposed to moderate
and regulate the combustion of explosive charges by delaying the passage of
ignition from grain to grain by coating the grains substantially as hereafter
described.
I have found that by thus retarding the ignition from grain to grain, so that
a charge burns progressively, the whole of the grains not being ignited until
some time after the initial ignition, depending on the thickness and nature
of the coating, a means is given to regulate the combustion of explosive charges,
which is of far more usefulness than the methods now in use. All gunpowders
now manufactured can be improved by my invention, that is, very much higher
velocities can be obtained without increase of the initial pressure.

page_text: In making explosive compounds according to this invention, I prepare granu
lated explosives by any of the well known methods, and coat the grains with a
non-explosive material such as any one, or a mixture of the waxes, resins, fatty
acids, fats or solid hydrocarbons, or a solid substance which when melted, has a
solvent action on the substance of the grain, for example the solid nitro hydr
carbons, coumarine, etc., or graphite mixed with an oleaginous substance or
metal dust or foil made to adhere by some suitable size. In no instances do
use substances which would cause the grains to cohere at a temperature below
150° F., which may be taken as the limit of service temperature.
In applying this coating I prefer to use, although I do not limit myself, a
drum such as is used for glazing. I add the substances to the granulated
powder in a finely divided form. The extent to which the grains are coated
being determined by the amount added and the duration of drumming. In
some instances I cause the drum to be heated, either during the whole or a part
of the time, so that the substances used for coating the grains become soft
With the substances used for coating the grains I may add graphite for glazing
or I may glaze after coating.
Powders made according to this invention, give standard velocities at a very
low initial pressure, exceptionally high velocities can be obtained without ex-
ceeding the normal pressures. An increase over and above the charge required
to give the standard velocity causes the velocities to increase in proportion, but
the initial pressure is not affected, or if so only to a slight degree, due no doubt
to the progressive nature of the ignition and combustion. All the grains of a
charge are not ignited until the projectile has moved some considerable extent,
therefore the charge burns as if it were ignited in a capacity larger than the
powder chamber. There is no need to airspace the charge, or perforate the
grains, as the combustion of a charge is progressive, and there is a gradually
increasing burning area and evolution of gases, as the ignition from grain to
grain progresses, and the projectile moves up the barrel. A large initial surface
is no longer an objection because it is not ignited at once. Thin grains can be
used, which is a great advantage owing to the difficulty of removing the
volatile solvent from grains of large dimensions. The moderating effect is
enhanced by the uniformity of the coating, and the thinner the coating may be,
the better is the result.
In powders treated according to my invention the moderating ingredients
are wholly or partially on the outside and not as hitherto wholly a component
of the explosive substances, and as the material on the outside has an effect
equal to five to ten times its weight, when mixed with the explosive substance,
obviously it is possible to carry the retardation to a much greater degree, with-
out too great a demand on the oxygen contents.
The initial ignition, which depends on the primer, obviously plays an
important part in the combustion of charges composed of gunpowders treated
according to this invention, this is more especially the case in guns of large
calibre and it gives an additional means whereby the effects of a charge may
be influenced.
Although in small bore cartridges the degree of coating has a limit, determined
by the failure of the usual primer to ignite the charge, yet within that limit the
velocities are exceptionally regular, and the time the bullet is moving up the
barrel is less than usual; the coating within practical limits increases the regu-
larity of action of an explosive compound.
That gunpowder is the best, which gives the greatest velocity to the pro-
jectile, without giving pressures above the standard pressures fixed by gun
construction, the powders treated according to this invention are a great advance-
ment in this direction.
I am aware that it has been proposed to make grains of layers of different
progressive rates of burning, the outer layer being the slowest; in these powders
the outer layer is of considerable thickness, and explodes so that the initial

page_text: combustion goes on as if the charge were composed of grains of the same com-
position as the outer layer. In powders made according to my invention the
coating is thin, non-explosive and on the outside, the advantages gained depend
upon the non-explosiveness of the coating which completely encloses or envelopes
each grain, and delays each individual grain from being immediately ignited,.
by absorbing the energy or flame of ignition, thus delaying the ignition through
the charge, making it progressive, and by varying the thickness and nature of the
coating, giving a means for regulating this progressive ignition and subsequent
combustion.
Dotad the 15th day of Tul., 1900
BREWER & SON,
Agents for the Applicant.
Improvements in or connected with the Treatment of Explosives.
I, FREDERICK WILLIAM JONES, of Barwick, Ware, in the County of Hertford,
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:-
The present invention relates to the treatment of explosives, and has for its
object to moderate and regulate the combustion of explosive charges, and is
more especially applicable to granulated "gelatinized" or dissolved" powders,
for use in guns of all calibres.
<<
It is well understood that the gunpowders known as gelatinised" or
« dis-
solved," under normal conditions burn only on the outside of the grains, and
therefore the evolution of the gases from a charge, or its combustion, is a
function of the superficies of the grains. Obviously, by varying the size, shape
and perforations of the grains, the rate of combustion of the grains is varied.
Such variation in shape, size and perforations of the grains, is the method now
in vogue, and is applied to all gelatinised explosive substances, to fit them for
guns of different calibres.
These factors must be determined with due regard to the rates of combustion
of the explosive substance, which is determined by its physical and chemical
nature in well understood ways, and depends on the nature of the solvent, and
the method of applying the same, and the explosive and moderating in-
gredients.
These methods depend on the rate of combustion of the grains and they assume
-as is the case with gunpowders of the present day-that the grains of a charge
are practically all ignited before the projectile moves any material distance along
the barrel. This ignition of the whole charge so early in the propulsion of the
projectile and in a chamber of comparatively small capacity, causes high initial
pressure, which is only partially remedied by air-spacing the charge, and thus
the weight of the charge, and thereby the velocity of the projectile, are limited
by considerations of gun construction.
I have found that a more beneficial effect can be obtained by delaying the
passage of ignition from grain to grain, by coating the grains substantially as
hereafter described, so that a charge burns progressively, the whole of the
grains not being ignited until some time after the initial ignition. The evolu-
tion of the gas will therefore commence successively in the different parts of the
charge and not practically at the same moment in all parts and thereby I can
use larger charges of powder with lower initial pressures without having the

page_text: grains of a size, form or material which will render the combustion too slow to
become complete before the projectile reaches the end of the barrel.
In making explosive compounds according to this invention; I prepare granu-
lated explosives by any of the well-known methods, and coat the grains with a.
non-explosive material such as any one, or a mixture, of the waxes, and solid.
hydrocarbons of high melting points or solid substances which when melted
have a solvent action on the substance of the grain, (for example dinitrotoluene, or
coumarin,) or graphite mixed with a small quantity of an oleaginous substance."
In no instances do I use substances which would cause the grains to adhere at a
temperature below 150° F., which may be taken as a limit of service temperature.
In applying this coating. I use a drum such as is used for glazing. I add the
covering, substance or substances in a finely divided form, to the granulated
powder. The extent to which the grains are coated, is determined by the
amount added and the duration of drumming. In some instances I cause or
allow the drum to become warm either during the whole, or a part of the time,
so that the substances used for coating the grains become somewhat soft to expedite
the operation. With the substances used for coating the grains I may add
graphite for glazing, or I may glaze after coating.
The moderating effect is enhanced by the uniformity of the coating and the
more uniform the coating the thinner it may be and the better the result.
In powders treated according to my invention, the substances which retard the
combustion of the charge are (so far as this invention is used to effect that pur-
pose) on the outside of the grain and not as hitherto, component parts of the
explosive. Material thus placed on the outside has a retarding effect, equal to
many times the effect of the same weight when mixed with the explosive so that
it is possible to carry the retardation to a much greater degree by my invention,
without too great a demand on the oxygen contents.
It is an essential of the applicability of my process that the covering material
should remain on the surface of the grains in a thin and practically continuous
coating. Thus the process is applicable to all impermeable powders, i.e., those
which have no tendency either by reason of their physical condition or their
composition to absorb the covering material, to any appreciable amount. If
however the powder can absorb to an appreciable extent the covering material,
or any of its ingredients or is permeable to it by reason of its physical condition
or its composition, it will not receive the attenuated coating essential to my
invention and there will be a tendency to hang-fire.
The initial ignition, (which depends on the primer), obviously plays an
important part in the combustion of charges composed of gunpowders treated
according to this invention, inasmuch as its size and intensity affects the range
of the initial ignition. This is more especially the case in guns of large calibre
and it gives an additional means whereby the effects of a charge may be
influenced.
So that my invention may be better understood I will describe how it can be
applied to a gelatinized granulated gunpowder.
The explosive base may be composed of any of the usual ingredients, and the
gelatinisation may be produced by any of the well known methods. In general,
manufacturers will find it advisable, to either make the grains thinner, or contain
less slowing ingredient, than is at present usual for the purpose in hand. The
grains dried and freed from solvent, are easily coated in a glazing drum, the
coating materials being added in a finely divided state. Carnauba wax and
ceresine of high melting point are excellent materials for this purpose. The
amount of coating will depend on the purpose for which the explosive is wanted;
in military guns the amount will increase as the size of the guns increase and
generally the amount will be smaller as pressures are smaller. It is not usually
advisable to use more than 3%. The best amount will readily be obtained by
experiment for any particular powder when the gun in which it is to be used
has been determined on. In practice it is necessary to add the covering material

page_text: in excess and after the drumming is finished to sift out what remains. The
longer the drumming the less the amount of this excess that need be used.
The surface layer must be distinct from the explosive grain, so that the ex-
plosiveness of the under-lying grain is not lessened, but on the other hand, this
surface layer must cohere to the grain. In general the rubbing action in
drumming produces the necessary degree of cohesion, but a moderate heating
of the drum may be employed to facilitate this result. The heating however,
must not be carried so far as to melt the materials used for covering the grain.
In special cases covering material like dinitrotoluene (which when heated are
solvents of the substance of which the grains are composed) may be used. When
using dinitrotoluene for this purpose I first crush it to an impalpable powder. I
then add it in the powdered form to a charge of the gunpowder in the drum.
The proportion of dinitrotoluene added will be considerably greater than the
proportion eventually taken up by the gunpowder, and may amount to as much
as say, 5 Ver cent. I then drum the mixture for a period of time, perhaps eight
hours, more or less, which suffices to cause the grain to take up so much of the
dinitrotoluene as is desired. I then remove the charge from the drum and sift
it in order to separate the coated gunpowder from the residue of dinitrotoluene.
I then take the coated powder and expose it in a suitable oven to a temperature
of about 70 deg. Cent. At this temperature the dinitrotoluene will melt but
being already evenly distributed over the grain it does not when brought into
the molten condition penetrate the grain, owing to the viscous nature of the
solid solvents and the small amount of nitro cellulose dissolved. The dinitro-
toluene remains where it has been placed and the only effect of its being brought
to the molten condition is that it becomes strongly adherent to the grain form-
ing a non-explosive shell. In all cases I prefer to glaze the coated grains with
graphite to make them smooth and easy to load with.
I will now describe in detail the treatment according to my invention of a
small bore rifle powder consisting of thin laminae of gelatinized gun cotton
such as now in use.
100 parts of this powder are drummed with 1 parts of finely divided Car-
nauba wax, for 8 hours, then sifted to separate the free wax. About 1.0% will
be found to cohere, in the form of an evenly distributed film. The powder
should afterwards be graphited.
I am aware that it has been proposed to make grains of layers of different
progressive rates of burning, the outer layer being the slowest; in these powders
the outer layer is of considerable thickness, and explosive so that the initial
combustion goes on as if the charge were composed of grains of the same com-
position as the outer layer. In powders made according to my invention, the
coating is thin, non-explosive, and on the outside, the advantages gained depend
upon the non-explosiveness of the coating which completely encloses or envelopes
each grain, and delays each individual grain from being immediately ignited,
thus lessening the extent of the initial ignition and delaying the ignition through
the charge, and making it progressive, and by varying the thickness and nature
of the coating, giving a means for regulating this progressive ignition and subse-
quent combustion.
Having now particularly described and ascertained the nature of this inven- .
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. The herein described method of taming and regulating the combustion
of granulated gunpowders, by covering. the grains with a non-explosive sub-
stance, such as is herein before described applied in the form of a thin shell
for the purpose and substantially as set forth.
2. The method of covering granulated explosives with solid substances which
when melted are solvents for the substance of the grains, and subsequently

page_text: finishing the covering shell and rendering it closely adherent to the grain by
heating the coated grains to a temperature above the melting points of the
substances used for covering them for the purposes and substantially as herein
set forth.
3. The herein described granulated gun powders tamed and regulated by being
covered with non-explosive substances such as are hereinbefore described applied
to the grains, substantially as set forth.
BREWER & SON,
London and Leeds, Agents for the Applicant.
BREWER & SON,
London and Leeds, Agents for the Applicant.