Improvements in Explosive Propelling Compounds and in Processes and Apparatus for their Manufacture.
Year: 1897

page_text: Improvements in Explosive Propelling Compounds and in Processes
and Apparatus for their Manufacture.
I, HUDSON MAXIM, of Thurlow Lodge, 377, Norwood Road, London, S.E., Chemist
and Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
The present invention relates to improvements in explosive propelling com-
pounds known as smokeless powders, and in process and apparatus for their
manufacture.
The invention has for its object mainly the production of an explosive com-
pound, in form of a multi-perforated body, the perforations being so shaped and
arranged as to present the minimum of burning surface to the flame of ignition
when fired in a gun, and be consumed with a constant increase of burning surface
or combustion area, whereby the pressure behind the projectile shall be substantially
maintained in its flight through the bore of the gun.
The compound which I prefer to employ consists of a colloid of guncotton, or
tri-nitro-cellulose, and di-nitro-cellulose, such a compound as is described in the
British provisional application of Robert Charles Schupphaus, No. 3,002, of 1897,
or I may employ a compound of tri-nitro-cellulose, gelatin-pyroxylin and nitro-
glycerin, described in my British Patent No. 16,311 of 1895, except that I may
employ an improved process of drying the explosive compound as hereinafter
described.
In carrying out my invention, a body of colloidal impervious explosive com
pound is multi-perforated with angular pins or mandrils, preferably either
hexagonal or three-sided, as hereinafter described, and in a manner described for
the use of round pins in my British Patent No. 16,862 of 1895, or as described
in my British Patent 8569 of 1895. A body of explosive compound so molded
presents a wall or body of explosive material between the perforations of a thick-
ness practically uniform, so that, when the powder is consumed by combustion
within the perforations, the total consumption of the powder will be completed at
the instant of interjunction of the perforations, and when the perforations shall
have attained their largest size.
Smokeless powder may in this manner be perforated either longitudinally or
transversely to the longitudinal axes of the grains, rods or strips employed. When
perforated longitudinally, the powder is preferably made by stuffing or squirting
through a suitable die, and the rod or grain may be either cylindrical or hexagonal,
but preferably hexagonal. When made hexagonal, the number of holes will be
preferably made according to the rapidity with which it is desired that the con-
sumption of the powder shall take place, according to the size of gun in

page_text: which it is intended to be employed. The number of holes may be either
seven, nineteen, thirty-seven, or sixty-one, or even only one, or still more than
sixty-one.
The preferable form is to make the powder, however, in rods or strips of a
length approximating the length of the powder chamber of the gun in which they
are to be employed, and transversely perforated as shown and described in my
British Patent No. 16,861 of 1895, except that the perforations be hexagonal and so
arranged with respect to one another as to secure best results and the rods or
strips may and are preferably made. rectangular, and the cross-section thereof
may be made of any desired size up to a point when the length of the perforations,
as compared with their diameter, becomes so great as to cause the pressure from
combustion within the perforations, to disrupt or break up the body of explosive
compound.
However, I may employ a multi-perforated body of explosive compound in hollow
cylindrical form, having hexagonal perforations opening into the interior of
the cylinder, and the cylinder may be made to approximate in size the powder
chamber of the gun, as described” and shown in my British Patent No. 16,862
of 1895.
When making a cylindrical rod longitudinally perforated with hexagonal per-
forations the rod has an external circular wall with radial walls connecting it
with the apexes of the outer angles formed with the external rows of hexagonal
perforations of the group of perforations centrally formed within the rod in
much the same manner as the cells of a honeycomb are connected with the walls
of its container by the action of the bees.
However, the preferable form of perforation for longitudinally perforated rods
of smokeless powder in cylindrical form is a three-sided perforation, the preferable
number being six, the apex of one of each of whose angles points to the centre
of the rod, the perforations having preferably two flat sides radiating from the
centre of the rod, and one rounded side running parallel to the external surface of
the cylinder. When the rod has a round central perforation the angular perfora-
tions are formed with an additional side parallel with the central perforation. By
this arrangement of perforations, all parts of the explosive body are simultaneously
consumed.
When employing a compound consisting mainly or wholly of pyroxylin or
pyroxylins, such as one of those above referred to, I have found an effective method
of evaporating the solvent from the same is to proceed in the following manner.
The material, when ready to be dried, is placed in a suitable chamber or receiver,
from which the air is preferably exhausted. The receiver is then charged with
the vapour of a volatile solvent, such as acetone, and by means of pipes through
which hot water is circulated, the temperature of the explosive compound is raised
beyond the boiling point of the acetone or volatile solvent employed in the
manufacture of the compound, which serves to drive out or expel the solvent from
the compound, while the same still remains in an atmosphere of or an atmosphere
charged with the vapours of a solvent of the compound, thus securing the drying
of the compound from the interior or deeper portions of the same, and at the same
time preventing the too rapid drying of the external surfaces thereof. This
prevents warping and cracking of the compound due to shrinkage of the surfaces
thereof upon an undried interior portion, and also prevents the formation at the
surfaces of a layer of very hard colloid which more or less obstructs the rapid and
efficient drying of the material.
Dated this Nineteenth day of March 1897.

page_text: Improvements in Explosive Propelling Compounds and in Processes
and Apparatus for their Manufacture.
HUDSON MAXIM, of Thurlow Lodge, 377, Norwood Road, London, S.E., Chemist
and 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 ascer-
tained in and by the following statement:
The present invention relates to improvements in explosive propelling com-
pounds known as smokeless powders, and in process and apparatus for their
manufacture.
The invention has for its object mainly the production of an explosive com-
pound, in form of a multi-perforated body, the perforations being so shaped and
arranged as to present the minimum of burning surface to the flame of ignition
when fired in a gun, and be consumed with a constant increase of burning surface
or combustion area, whereby the pressure behind the projectile shall be substantially
maintained in its flight through the bore of the gun.
The compound which I prefer to employ consists of a colloid of guncotton, or
tri-nitro-cellulose, and di-nitro-cellulose, or I may employ a compound of tri-
nitro-cellulose, gelatin-pyroxylin and nitro-glycerin, described in my British
Patent No. 16,311 of 1895, except that I may employ an improved process of drying
the explosive compound as hereinafter described.
In the accompanying drawings Figs. 1 to 6 illustrate forms of powder grains
perforated in various ways according to my invention.
In carrying out my invention, a body of colloidal impervious explosive com-
pound is multi-perforated with angular pins or mandrills, preferably either
hexagonal or three-sided, as hereinafter described, and in a manner described for
the use of round pins in my British Patent No. 16,802 of 1895, or as described
in my British Patent 8569 of 1895. A body of explosive compound so molded
presents a wall or body of explosive material between the perforations of a thick-
ness practically uniform, so that, when the powder is consumed by combustion
within the perforations, the total consumption of the powder will be completed at
the instant of interjunction of the perforations, and when the perforations shall
have attained their largest size.
Smokeless powder may in this manner be perforated either longitudinally or
transversely to the longitudinal axes of the grains, rods or strips employed. When
perforated longitudinally, the powder is preferably made by stuffing or squirting
through a suitable die, and the rod or grain may be either cylindrical or hexagonal,
but preferably hexagonal. When made hexagonal 1, (see Fig. 1,) the number of
perforations 2, will be preferably made according to the rapidity with which it
is desired that the consumption of the powder shall take place, according to the
size of gun in which it is intended to be employed. The number of perforations
may be either seven, nineteen, thirty-seven, or sixty-one, or even only one, or
still more than sixty-one.
The edges or sides of the powder grain may be grooved at, 3, in order that the
consumption of the powder may extend into such parts of the grain that may not
be reached by the combustion within the perforations, and the external com-
bustion at the instant of the interjunction of the perforations. The final size of
the perforations at the moment before the total combustion of the grain is shown
on dotted lines on each figure.
The preferable form, however, is to make the powder, in rods or strips 1, (see
Fig. 2), of a length approximating the length of the powder chamber of the

page_text: gun in which they are to be employed, and transversely perforated as shown
and described in my British Patent No. 16,861 of 1895, except that the perfora-
tions 2, be hexagonal and so arranged with respect to one another, together with
the grooves, 3, in the sides of the grain as to secure best results and the rods
or strips may and are preferably made rectangular, and the cross section thereof
may be made of any desired size up to a point when the length of the perforations,
as compared with their diameter, become so great as to cause the pressure from
combustion within the perforations, to disrupt or break up the body of explosive
compound.
However, I may employ a multi-perforated body of explosive compound in
hollow cylindrical form, 4, (see Fig. 3) having hexagonal perforations, 2, opening
into the interior of the cylinder, and the cylinder may be made to approximate in
size the powder chamber of the gun, as described and shown in my British Patent
No. 16,862 of 1895.
When making a cylindrical rod longitudinally perforated with hexagonal per-
forations, 2, (see Fig. 4,) the rod has an external circular wall, 5, with radial
_walls 6, connecting it with the apexes of the outer angles formed with the
external rows of hexagonal perforations of the group of perforations centrally
formed within the rod in much the same manner as the cells of a honeycomb are
connected with the walls of its container by the action of the bees.
However, the preferable form of perforation for longitudinally perforated rods
of smokeless powder in cylindrical form (see Fig. 5) is a three-sided perforation, 7,
the preferable number being six, the apex of one of each of whose angles points
to the centre of the rod, the perforations having preferably two flat sides radiating
from the centre of the rod, and one rounded side running parallel to the external
surface of the cylinder. When the rod has a round central perforation, 8, (see
Fig. 6) the angular perforations, 7, are formed with an additional side parallel
with the central perforation. By this arrangement of perforations, all parts of
the explosive body are simultaneously consumed.
When employing a compound consisting mainly or wholly, of pyroxylin or
pyroxylins, such as one of those above referred to, I have found an effective method
of evaporating the solvent from the same, is to proceed in the following manner.
The material, when ready to be dried, is placed in a suitable chamber or receiver,
from which the air is preferably exhausted. The receiver is then charged with
the vapour of a volatile solvent, such as acetone, and by means of pipes through
which hot water is circulated, the temperature of the explosive compound is
raised beyond the boiling point of the acetone or volatile solvent employed in the
anufacture of the compound, which serves to drive out or expel the solvent
from the compound, while the same still remains in an atmosphere of,
or an atmosphere charged with, the vapours of a solvent of the compound
thus securing the drying of the compound from the interior or deeper
portions of the same, and at the same time preventing the too rapid drying of the
external surfaces thereof. This prevents warping and cracking of the compound
due to shrinkage of the surfaces thereof upon an undried interior portion, and also
prevents the formation at the surfaces of a layer of a very hard colloid which
more or less obstructs the rapid and efficient drying of the material.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The herein described process of manufacturing an explosive compound for
use in guns, which consists in forming a body of explosive material into rods,
strips, or grains, of a desired shape, having perforations, of such shape, and so
arranged with respect to one another as to effect the complete consumption of the
explosive body at the instant of the interjunction of the perforations with one
another from their enlargement by interior combustion.

page_text: 2. A body of explosive compound, multi-perforated with angular perforations,
for the purpose above specified.
3. A longitudinally perforated rod or grain of explosive compound, having a
round central perforation, and other perforations having four unequal sides, with
the longest side nearest the circumference of the rod or strip, and preferably
parallel or concentric with the external surface of the same, for the purpose above
specified.
4. A multi-perforated body of explosive compound, having perforations so shaped
and arranged with respect to one another, as to present burning surfaces concentric
with, and, or parallel with one another, for the purpose above specified.
1000
W. H. GRAHAM,
Agent for Hudson Maxim.
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CIRURG TO CREAT SUM
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W. H. GRAHAM,
Agent for Hudson Maxim.