IMPROVEMENTS IN THE MANUFACTURE OF * PEBBLE' GUNPOWDER AND IN MEANS OF ADDADA MITA TAR
Year: 1870

page_text: LETTERS PATENT to Frederick Burney, of Faversham, in the County
of Kent, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
* PEBBLE' GUNPOWDER AND IN MEANS OF
ADDADA MITA
TAR
"
PROVISIONAL SPECIFICATION left by the said Frederick Burney at
the Office of the Commissioners of Patents, with his Petition, on
the 26th October 1870.
I, FREDERICK BURNEY, of Faversham, in the County of Kent, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF PEBBLE' GUNPOWDER AND IN MEANS OR APPARATUS FOR THE
SAME," to be as follows:-
My Invention relates to the manufacture of what is known as " pebble"
gunpowder, being gunpowder formed into grains of large size.
According to my Invention I mould the powder or "mill cake " as
received from the amalgamating mill into "pebble" powder at one
operation, the powder being formed into lumps or grains of a uniform
size and shape. For this purpose I compress a layer of mill cake

page_text: between plates or moulds worked by hydraulic or other pressure, by
which the powder or mill cake is condensed into uniform lumps of the
desired size. The plates forming each half of the mould are made
precisely alike, each being formed with a number of cells or recesses of
uniform shape or size. These cells are made angular in form with
inclined sides to facilitate the removal of the compressed powder. The
cells cover the whole surface of the plate or mould without any inter-
vening flat surface, so that the whole of the pressure is exerted on the
powder in the cells. In moulding the cells of the two plates are made
to coincide, one half of the grain or lump into which the powder or mill
cake supplied to the mould is pressed being formed by each plate. By
this means grains or lumps are made of angular form (octahedrons
for instance), each cell in the plate forming one half of the figure
produced.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Frederick Burney in the Great Seal Patent Office
on the 26th April 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
BURNEY, of Faversham, in the County of Kent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of October, in the
year of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Frederick Burney, Her special licence that I,
the said Frederick Burney, my executors, administrators, and assigns, or
such others as I, the said Frederick Burney, my executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time, and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
• PEBBLE' GUNPOWDER AND IN MEANS OR APPARATUS FOR THE SAME," upon the
condition (amongst others) that I, the said Frederick Burney, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and

page_text: ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederick Burney, do hereby declaro
the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by
the following statement, reference being had to the Sheet of Drawings
hereunto annexed, and to the letters and figures marked thereon (that is
to say) :-
My Invention relates to the manufacture of what is known as "pebble"
gunpowder, being gunpowder formed into grains of large size.
According to my Invention I mould the meal or broken down mill
cake received from the amalgamating mill into "pebble" powder at one
operation, the powder being formed into "grains" of a uniform size and
shape. For this purpose I compress a layer of broken down mill cake
between plates or moulds worked by hydraulic or other pressure, by which
the meal or broken down mill cake is condensed into uniform grains of
the desired size. The plates forming each half of the mould are made
precisely alike, each being formed with a number of cells or recesses of
uniform shape and size. These cells are made angular in form with
inclined sides to facilitate the removal of the compressed powder. The
cells cover the whole surface of the plate or mould without any inter-
vening flat surface, so that the whole of the pressure is exerted on the
powder in the cells. In moulding the cells of the two plates are made
to coincide, one half of the "grain" into which the powder or mill cake
supplied to the mould is pressed being formed by each plate. By
this means grains are made of angular form (octahedrons. for instance),
each cell in the plate forming one half of the figure produced.
DESCRIPTION OF DRAWINGS.
Figure 1 shows a transverse section of a portion of a pair of the mould
plates separated after having compressed the powder placed between

page_text: A and B are the upper and lower mould plates respectively, they are
mounted in an hydraulic press (not shown), the upper plate A being fixed
by clamps around its bevelled edges bolted to the head or top of the
press frame, and the lower plate B supported on the follower of the
press, but without being fixed thereto, in a position exactly parallel with
the upper plate A. The cellular surfaces of the two moulds or plates
face one another, and studs or pins are fixed on the follower for the
plate B to abut against when in position, and so make the cells in the
two plates coincide exactly when brought together. The plates are of
metal (preferably gun metal), and are formed by casting in moulds each
with cells or moulds of uniform shape and size covering one surface.
These cells whether square in plan as shown in Figure 2, or of triangular,
diamond, or hexagonal form, as shown in Figures 3, 4, and 5, are so
disposed close together that the whole surface of the plate is occupied,
the inclined sides of contiguous cells meeting one another at an angle
without any intervening flat surface between the cells or round the edges,
the plates presenting the appearance of a honeycomb. The sides of the
cells are inclined to facilitate the removal of the compressed powder and
meet in an apex at the centre. The cells may however be slightly filled
in to round off or flatten the apex of the grain or "pebble," as sharp
angles are liable to be abraded in packing. When the cells are made of
the shape shown in Figure 2, the grain or "pebble" of compressed powder
will be in the form of an octahedron, as shown in Figures 1 and 6, the
grains formed by plates having cells as in Figures 3, 4, and 5 being shown
in Figures 7, 8, and 9 respectively.
The operation is as follows:-A supply of meal or broken down mill
cake is placed on the lower or moveable plate B in a uniform layer of
suitable depth according to the degree of density required. The said
plate B is then placed in position on the follower of the press, and the
two plates being then brought close together by the motion of the
follower, pressure is exerted on the whole layer of mill cake, which is
compressed in the cells into the form of "grains," one half of every grain
being formed in each plate. The plates are then caused to recede, and
the plate B being withdrawn from the press the compressed grains
which remain thercon may be removed. As the plates do not actually
meet the grains or “pebbles" will be slightly connected at the edges, but
they may be easily separated by hand, and are then ready to be glazed as
usual. Several pairs of mould plates, cach pair having a layer of mill cake

page_text: between them, may be superposed on the press follower and simul-
taneously compressed at one stroke of the press, the plates being held in
position and guided by the pillars or framework of the press."
Having described the nature of my Invention and the manner of
performing the same, I declare that what I claim as my Invention to be
protected by the herein-before in part recited Letters Patent is,-
1st. Moulding meal gunpowder or broken down mill cake into
'pebbles" or "grains" of large size at one operation by pressure
between plates having cellular surfaces, as above described.
2ndly. I claim making the said mould plates with honeycombed or
cellular surfaces, the cells being shaped and arranged substantially as
herein-before described and for the purpose specified.
In witness whereof, I, the said Frederick Burney, have hereunto set
my hand and seal, this Twenty-fifth day of April, in the year of our
Lord One thousand eight hundred and seventy-one.