IMPROVEMENTS IN THE PREPARATION OR MANUFACTURE OF GUNPOWDER CHARGES FOR BL STING
Year: 1875

page_text: LETTERS PATENT to Hunter Henry Murdoch, of No. 7, Staple Inn, in
the County of Middlesex, Patent Agent, for the Invention of
“IMPROVEMENTS IN THE PREPARATION OR MANUFACTURE OF GUNPOWDER
CHARGES FOR BL STING."-A communication from abroad by Herman
Müller, of Clermont, in the Kingdom of Belgium, Gunpowder
Manufacturer.
4
L
PROVISIONAL SPECIFICATION left by the said Hunter Henry
Murdoch at the Office of the Commissioners of Patents, with his
Petition, on the 22nd May 1875.
I, HUNTER HENRY MURDOCH, of No. 7, Staple Inn, in the County of
Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE PREPARATION OR MANUFACTURE OF
GUNPOWDER CHARGES FOR BLASTING," to be as follows:-
For blasting purposes it has hitherto been usual to use gunpowder
in grains of variable size and cartridges or full charges of compressed
gunpowder.

page_text: According to theory the powder to produce its full effect on the rock
to be blasted should not explode too sharply or too quickly, and it has
been proposed to retard its combustion by varying the proportion of its
constituents, but the effect of this is to diminish the gaseous volumė
evolved and consequently the quality and explosive force of the powder.
It has also been proposed to retard the combustion of the powder by
compression and by increasing the size of the grains, the proportions and
quality of the ingredients being such as to produce the greatest possible
volume of gas, and consequently the greatest effect: By this means the
rapidity of combustion decreases in proportion as the amount of com-
pression and the size of the grains or pieces of compressed powder aro
increased. This last method is evidently preferable to the former one,
but there remains the difficulty of obtaining the same effect regularly
from grains varying in size, shape, and density, and such gunpowder
requires considerable manipulation in charging the blast hole.
Now this Invention consists in forming blasting charges of pieces of
compressed gunpowder or gunpowder cake, such piecces being of
uniform size and suitable for being readily introduced into the blast hole
and having the required density for their combustion to be as nearly as
possible such as is desirable in theory.
The powder used according to this Invention is such as will produce
the greatest possible volume of gas, and it may be either mealed or
granulated. The said powder is formed into rings or pieces of the
required size and density, with holes through their centres, so that the
quantity required to make up the blasting charge may be threaded or
strung upon a match or fuzee like the beads of a chaplet.
The said rings or pieces of powder may be of circular, square,
hexagonal, or any other suitable shape, with plain or convex surfaces
and with or without grooves, ribs, projections, or any kind of angular
parts formed upon them. They may be perforated entirely or partially
with one or more holes or depressions besides the central hole herein-
before referred to as serving to thread them upon the match or fuzee,
and if desired their external peripheries may be ribbed so as to present
the greatest possible extent of surface for the ignition of the whole
charge as well as of all its component parts, it being important that every
part of the blasting charge should ignite simultaneously.

page_text: The said rings or pieces of compressed gunpowder may be made either
by-cutting them out of powder cakes compressed in a press, or they
may be made by the action of two compressing pistons caused to
move one towards the other, or suitable punches or other mechanical.
means may be used in the manufacture of the said rings or pieces of
compressed gunpowder.
After having been threaded or strung upon a suitable match or fusee,
the said rings or pieces of compressed powder form a blasting charge
capable of bending, so as to accommodate itself to the irregularities of
the blasting hole.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Hunter Henry Murdoch in the Great Seal Patent
Office on the 19th November 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HUNTER
HENRY MURDOCH, of No. 7, Staple Inn, in the County of Middlesex,
Patent Agent, send greeting.
'
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of May, in the year:
of our Lord One thousand eight hundred and seventy-five, in the thirty-
cighth year of Her reign, did, för Herself, Her heirs and successors,
give and grant unto me, the said Hunter Henry Murdoch, Her special,
licence, that I, the said Hunter Henry Murdoch, my executors, adminis-
trators, and assigns, or such others as I, the said Hunter Henry.
Murdoch, my executors, administatrors, and assigns, should at any time
agree with, and no others, from time to time and at all times there-.
after 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 PREPARATION OR MANUFACTURE OF Gun-
POWDER CHARGES FOR BLASTING," (a communication to me from abroad by
Herman Müller, of Clermont, in the Kingdom of Belgium, Gunpowder
Mánufacturer,) upon the condition (amongst others) that I, the said
Hunter Henry Murdoch, my executors or administrators, by an instru-;

page_text: ment in writing under my, or their, or one of their hands and
seals, should particularly describe and 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 Hunter Henry Murdoch, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say :
-
For blasting purposes it has hitherto been usual to use gunpowder in
grains of variable size, and cartridges or full charges of compressed
gunpowder.
According to theory, the powder to produce its full effect on the rock
to be blasted should not explode too sharply or too quickly, and it has
been proposed to retard its combustion by varying the proportion of its
constituents, but the effect of this is to diminish the gascous volume
evolved, and consequently the quality and explosivo force of the powder.
It has also been proposed to retard the combustion of the powder by
compression and by increasing the size of the grains, the proportions
and quality of the ingredients being such as to produce the greatest
possible volume of gas and consequently the greatest effect. By this
means the rapidity of combustion decreases in proportion as the amount
of compression and the size of the grains or pieces of compressed powder
are increased. This last method is evidently preferable to the former,
but there remains the difficulty of obtaining the same effect regularly
from grains varying in size, shape, and density, and such gunpowder
requires considerable manipulation in charging the blast hole.
Now this Invention consists in forming blasting charges of pieces of
compressed gunpowder or gunpowder cake, such pieces being of uniform
size and suitable for having readily introduced into the blast hole, and
having the required density for their combustion to be as nearly as
possible such as is desirable in theory.
The powder used, according to this Invention, is such as will produce
the areatest possible volume of an's and it may be either mealed or 1

page_text: •
'
Figure 3 is a plan of an octagonal piece of compressed gunpowder w
perforated at its centre a¹ for the passage of a match or fuze, and having
further perforations or depressions a³, a³, in it.
Figure 4 shows a piece of gunpowder of circular form a perforated
at its centre a³, and having in it further perforations or depressions a²;
and grooves a³, a³, may extend from the centre hole a¹ to the periphery
of the piece, as shown.
The said pieces of compressed gunpowder may be made into other
shapes than those, represented, and their surfaces may be either plain
or convex or bulging out, and if desired, ribs, projections, or angular
parts may be formed upon them.
Figure 5 represents in vertical section a portion of a rock with a
blasting hole bored therein, in which is a blasting charge of gunpowder
rings threaded on a match or fuze. According to this Invention A is the
rock, B the blasting hole, a, a, a, are the gunpowder rings which are 1
strung on the match or fuze 6; c is the knot of the said match or fuze,
and d is the filling in or "tamping" of the blasting hole. The charge
thus made up is capable of bending so as to accommodate itself to any
irregularities in the blasting hole.
The rings or pieces of gunpowder herein-before described, are made
by cutting them out of gunpowder cakes compressed in a hydrostatic
press, or the said rings may be made by the action of two compressing
pistons advancing towards and retiring from each other alternately, or
by suitable punches or other means.
Having now described the nature of this Invention and the manner
of performing the same, I wish it to be understood, that I do not confine
myself to the precise details herein-before described and illustrated in
the accompanying Drawings, as the said details may be varied without
departing from the nature of the said Invention. But I claim as the
said Invention of improvements in the preparation or manufacture of
gunpowder charges for blasting, compressing gunpowder into or cutting
out of gunpowder cake rings or pieces of circular, square, hexagonal,
or other suitable shape, perforated in the centre, and with or without ribs
or projections upon them, or grooves, depressions, or additional holes in
them; the surfaces of the said rings or pieces of gunpowder being flat
E

page_text: or convex, and their peripheries plain, or ribbed, or undulated, and
threading a number of the said rings or pieces of compressed gunpowder
upon a match or fuze, so as to form an effective blasting charge
essentially as herein-before described and illustrated in the accom-
panying Drawings.
In witness whereof, I, the said Hunter Henry Murdoch, have
hereunto set my hand and seal, this Nineteenth day of November,
in the year of our Lord, One thousand eight hundred and seventy-
five.
0
Witness,
B. WILLOOX,
his Clerk.
H. H. MURDOCH. (L.S.)