An Improved Method of and Apparatus for Measuring the Power of Explosives.
Year: 1898

page_text: An Improved Method of and Apparatus for Measuring the Power
of Explosives.
I, CHRISTIAN EMIL BICHEL, of 1, Alsterdamm, Hamburg, in the Empire of
Germany, Director, do hereby declare the nature of this invention to be as
follows:
By this improved method and apparatus, appertaining thereto, it is possible,
to simultaneously measure the explosive power of explosives and their mixtures
in a very exact and reliable manner, without any circumstantial operations, by
the aid of a known indicator, and in a manner not heretofore attained.
A cartridge of the explosive to be examined or tested is placed into the hollow
space of a thick-walled cylinder provided with a blasting box or capsule adapted
to be exploded by electric ignition wires, and the explosion chamber of the
cylinder is closed gas tightly by means of a cover. Thereupon a partial or,
under given circumstances a perfect vacuum is produced in the explosion
chamber and the cartridge then exploded by an electric spark. By the gases
resulting from the explosion, the piston of an indicator, connected with the
explosion chamber is set in motion, the pin, or style of which is adapted to draw
a curve upon the periphery of a rotary drum, actuated by clockwork; from
this curve the brisancy and power of the explosive can be derived
The ignition of the cartridge in a partial or perfect vacuum may also be
effected in the presence of an inert gas such, for example, as nitrogen, although
this method has the disadvantage, that the expansion of the nitrogen, resulting
from the latter being heated, must be taken into account and that, in view of
the very high temperatures of explosion, the oxygen, contained in the decomposed
gases, would also have an oxydizing effect upon the nitrogen. In a sufficiently
rarified space, on the contrary, the decomposed gases, resulting from the explosive,
act independently without any foreign influence, and the explosion takes place
under the same chemical and physical conditions as it occurs in reality in the
blast hole made in coal or rock.
The capacity of the explosion chamber may be more or less reduced by inserting
pieces into said chamber.
One method of connecting the igniting device, so arranged, that, when the
drum occupies a certain position, an extra current is generated, which causes
the blasting box or capsule of the cartridge to be ignited. In addition, thereto,
conducting wires pass from the battery to the ignition-capsules as well as to a
switching-contact device, and in these conducting wires current breaking devices
and a coil having a bundle of iron rods located in its interior, are inserted.
D
011

page_text: After the clock work, which actuates the drum, has been released, and after
the rotary speed of the drum has been found to be uniform by means of electric
bell signals, the coil is inserted into the circuit of the battery by successively
closing the contacts, whereupon the current traverses the path, battery, resistance
coil, first contact, second contact back to battery. If subsequently the first
contact is opened, the current is caused to traverse the path, battery, resistance
coil, switching contact device to second contact and battery until a pin of the drum
lifts the contact switching contact off and thus interrupts the current. Thereby
an extra current is generated in the known manner in a shunt-circuit, which
extra current ignites the blasting box or capsule in the interior of the explosion
chamber, and this always at a time, when the drum has a certain portion of its
periphery located opposite the indicating style, so that the drawing of the diagram
is always commenced at a given point, which is essential for obtaining easily
legible and measurable diagrams.
Dated this 25th do
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
An Improved Method of and Apparatus for Measuring the Power
of Explosives.
I, CHRISTIAN EMIL BICHEL, of 1, Alsterdamm, Hamburg, in the Empire of
Germany, Director, 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:-
By this improved method, and apparatus appertaining thereto, it is possible,
to simultaneously measure the explosive power and brisancy of explosives and
their mixtures in a very exact and reliable manner, without any circumstantial
operations, by the aid of a known indicator, and in a manner not heretofore
attained. This is accomplished by causing the explosion of the substances to be
tested to take place under the same chemical and physical conditions as it occurs
in the blast hole and to this effect the ignition by the aid of electricity of the
explosive to be tested is performed in a rarefied space or in the presence of an
inert gas, so that the decomposed gases developed on explosion act independently
and without any foreign influence upon the indicator.
In order to make my invention more clearly understood I will proceed to
describe the same, by way of example, with reference to the accompanying
drawing, in which:
:-
Figure 1 is an end view of an apparatus for measuring the explosive power
and brisaney of an explosive, as it appears after the removal of the cover closing
the explosion chamber;
Figure 2 is a longitudinal section of the apparatus;
Figure 3 illustrates the course of a line on the paper of the indicator, from
which the power and brisancy of the explosive may be ascertained, and
Figure 4 is a diagram of the electric ignition device.
Similar letters denote similar parts throughout the several views.
A cartridge a of the explosive to be examined or tested is placed into the
hollow space of a thick-walled cylinder e provided with a blasting box or cap‐
sule a adapted to be exploded by electric ignition wires and b, and the

page_text: explosion chamber of the cylinder is closed gas tight by means of a cover c'.
Thereupon a partial or, under given circumstances, a perfect vacuum is produced
in the explosion chamber by connecting the latter through the medium of an
adjustable valve 2 with an air pump, and the cartridge then exploded by an
electric spark. By the gases resulting from the explosion, the piston of an
indicator d, connected with the explosion chamber is set in motion, the pin, or
style of which is adapted to draw a curve upon a strip of paper laid around
the periphery of a rotary drum e actuated by a clock-work in the usual manner;
from this curve, Figure 3, the brisancy and power of the explosive can be
derived.
The ignition of the cartridge may also be effected in the presence of an inert
gas such, for example, as nitrogen, although this method has the disadvantage,
that the expansion of the nitrogen, resulting from the latter being heated, must
be taken into account and that, in view of the very high temperature of explosion
the oxygen, contained in the decomposed gases, would also have an oxydizing effect
upon the nitrogen. In a sufficiently rarified space, on the contrary, the decom-
posed gases, resulting from the explosive, act independently without any foreign
influence, and the explosion takes place under the same chemical and physical
conditions as occurs in reality in the blast hole made in coal or rock.
The capacity of the explosion chamber may be more or less reduced by inserting
pieces into said chamber, as is indicated by dotted lines in Figure 2.
I am accustomed to use an igniting device diagrammatically illustrated by
Figure 4 and so arranged, that, when the drum e of the indicator occupies a
certain position, an extra current is generated, which causes the blasting box
or capsule of the cartridge to be ignited. In addition thereto, conducting wires
pass from the battery or other source of electricity h to the ignition-capsule a as
well as to a switching-contact-device 121, and in these conducting wires current
breaking devices n, o and a coil f having a bundle of iron rods fi located in its
interior, are inserted.
After the clock-work, which actuates the drum e and which is not particularly
illustrated in the drawing, has been released, and after the rotary speed of the
drum has been found to be uniform by means of electric bell signals, the coil f
is inserted into the circuit of the battery h by successively closing the contacts o
and n, whereupon the current traverses the path, battery h, wire g², resistance
coil f, first contact o, wire g', second contact n and back to battery h. If subse-
quently the first contact o is opened, the current is caused to traverse the path,
battery h, wire g², resistance coil f, wire 22, switching contact device,
wires g, to second contact n and battery h until a pin of the indicator drum e
lifts the contact switching contact 2 off k¹ and thus interrupts the current.
Thereby an extra current is generated in the known manner in the shunt-
circuit f,, 61, 62, 3, which extra current ignites the blasting box or
in the interior of the explosion chamber, and this always at a time, when the
capsule a¹
drum has a certain portion of its periphery located opposite the indicating
style d, so that the drawing of the diagram is always commenced at a given
point, which is essential for obtaining easily legible and measurable diagrams.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same may be performed, I declare that what
I claim is:-
1. The herein described method of measuring the power and brisancy of explo-
sives, which consists in effecting the ignition of the explosive by an electric spark
in a chamber partially or perfectly evacuated or filled with an inert gas, and
admitting the decomposed gases, resulting from the explosion, to act upon an
indicator of known construction connected with the explosion chamber, sub-
stantially as and for the purpose set forth.
2. In an apparatus for measuring the power and brisancy of explosives, the
combination of an explosion chamber, the capacity of which may be more or less

page_text: reduced by filling pieces and being in connection with an air or gas-pump and
an indicator for drawing diagrams, with an electric igniting device comprising
a switching contact (2) for automatically breaking the current at a given
moment and a shunt-circuit coil (f f¹), substantially as and for the purpose set
forth.
Datal thin 25th day of Ma... 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.