Improvements in Means to be employed in Igniting Blasting Charges.
Year: 1895

page_text: Date of Application, 19th Feb., 1895-Accepted, 23rd Mar., 1895
COMPLETE SPECIFICATION.
Improvements in Means to be employed in Igniting Blasting
Charges.
I CARL ROTH of Villa Roth Hennickendorf in the Empire of Germany 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:―
This invention relates to means for igniting blasting charges and has reference to
the system described in the Specification of Letters Patent No. 23417 granted to
me and dated the 5th December 1893 wherein gases or other fluids, such as are
indicated in the said Specification, are conducted to the substances which in
conjunction therewith produce an explosion the gases or other fluids being according
to my present invention conducted through a channel formed in the substance of
the tamping and extending along the bore or blast hole to the orifice at the end of
the blasting charge or cartridge or the detonator thereof (I will refer to it as the
cartridge). The escape of air may also be provided for, by a channel formed in
the same way in cases where the portion of the bore-hole wherein such cartridge
is embedded, is not wide enough, or the material is not sufficiently porous, to allow
the air to escape.
According to my present invention the channel is or channels are formed in the
tamping by means of a tube, wire, cord or the like which extends from the cartridge
back through the blasting hole the tamping material being then rammed in and
the tube, wire, cord or the like withdrawn leaving the requisite channel or channels
for conducting the fluid to the cartridge and if necessary for allowing the air to
escape.
A simple method of so forming the said fluid-conducting channel consists in
pushing forward the cartridge into the bore or blast hole by means of a tube or
rod (say from to ½ of an inch in diameter) in the direction of the longitudinal
axis (or thereabouts) of the bore or blast hole, up to the extremity thereof. The
bore or blast hole around the said tube or rod next to the cartridge is then tamped or
filled in with material presenting interstices for the passage of air such as balls or
masses of paper or similar material such filling of paper or the like extending from
the end of the tube or rod next the cartridge backwards for a distance of say
about of an inch and then the bore or blast hole for the remaining length around.
the tube or rod is filled in with any of the usual or suitable tamping materials such
as clay, stone-dust, loam or the like. In order that the detonating materials or
priming enveloped in a paper or metal case at the front end of the cartridge, may
be adequately protected while being conveyed through the bore or blast hole, the
tube or rod employed in introducing the cartridge should be made sufficiently wide
or so formed at its end that it does not come in contact with the priming. When
the bore or blast hole has been thus tamped and the said tube or rod has been
removed there remains in the tamping a channel of the size of the said tube or rod.
Instead of the said rod or tube any other device may be used such as a wire or
cord secured to or in the cartridge and the cartridge be introduced in any suitable
way the wire or cord following it and being held or supported in the requisite
position whilst tamping and being afterwards withdrawn.
:
When an air outlet is required it may be provided by forming another chaunel
in the same manner as that described for forming the fluid conducting channel.

page_text: A simple plan is to fix a piece of cord which should exceed the length of the bore or
blast hole by say an inch at least to the outside of the cartridge, by means of pitch,
and then to put the cartridge in position in the bore or blast hole. Then after the
materials have been filled into the bore or blast hole as before described the cord
is removed it being readily pulled off the said cartridge and the required channel
is left.
Figure 1 of the accompanying drawings shews a section of a bore or blast hole
containing a cartridge S. The detonator of the said cartridge is connected with
the gas or fluid supply channel E (formed as aforesaid) by a small strip or tube C
of any suitable material such as paper or wood coated with a priming mixture on
its outer surface which may be roughened for the purpose the arrangement being
such that the fluid for effecting ignition passing through the said channel E must
pass into the tube C such tube projecting a little into the said channel and
leaving a space outside it for the escape of air where chlorine gas is used for
effecting ignition, the tube C (which is but loosely held between the detonator walls
and terminates within the filling material of the detonating cap) may be coated, for
example, with a mixture of finely powdered sulphur (1 part by volume) and yellow,
precipitated oxide of mercury (3 parts by volume) or with a mixture composed of
an equal number of parts, by weight, of red phosphorus and nitrate of potash.
These or similarly acting substances when the detonator or explosive used is readily
inflammable, may if preferred be placed upon instead of within the cartridge and
when the current of chlorine or similarly acting gas comes into contact with them,
they become ignited and so heated that the temperature required for the explosion
is transmitted to the detonator or explosive.
For firing the following arrangement may be used. A bent tube R is first
inserted into the channel E, the joint between it and the said channel at B', being
tightly closed by means of a filling material such as clay, gypsum or the like. G is
a bottle or jar containing say concentrated hydrochloric acid into which is introduced
say a piece of permanganate of potash which may be coated with a passive or
neutral substance by which the explosion is properly timed as described in the
Specification of my aforesaid Patent 2341793. The end of the tube R is introduced.
through the closure of the bottle G and the said bottle is closed. If carbonate of
zinc be used as the covering for the permanganate of potash the carbonic acid gas
developed in the said bottle displaces the air from the bottle and tube R and
channel F through the material at P and thence through the discharge channel A
into.. the atmosphere. The carbonic acid, gas follows the air and it does not
interfere with subsequent ignition or detonation by the action of chlorine and it
expels any fire damp there may be in the passages so that the explosion takes
place in a medium of an inert gas.
Instead of hydrochloric acid and the substances developing chlorine (or other
gas capable of acting similarly to chlorine, in conjunction with such substances as
are capable of co-operating with them, respectively for igniting blasting charges)
concentrated sulphuric acid and a pellet or piece of sodium carbonate may be used
the tube R in this case extending down to near the bottom of the bottle so that
the sulphuric acid will by the generation of gas, creating pressure within the bottle,
be forced through the tube R and channel E to the cylinder or tube C or its
equivalent which may in this case be coated with a mixture of chlorate of potash
and sugar and so that the acid on touching the tube C will cause an explosion to
take place. The tamping through which the channel E'extends should as far as
possible be chemically of a passive or inert nature.
Where a liquid is employed it may be poured into the supply channel from
above the cartridge bed if conditions be such as will permit the liquid to descend
by gravity. Among the fluids which may thus be brought into contact with
substances capable of producing a detonation or explosion in combination with
them, I may mention for example a highly concentrated solution of nitric acid or
other oxidizing agents capable of producing explosions when in contact either with
explosives having phosphorus for their main constituent or with metallic potassium

page_text: enclosed in a destructible case or with similarly enclosed ammonia either in a
gaseous compressed form, or dissolved in alcohol.
For the purpose of controlling the supply of fluid, and thereby timing the
explosion, the simplest means is to provide either a funnel-shaped receiver or
supply channel with a reduced or contracted neck, so proportioned as to afford a
passage only to an exactly predetermined quantity of liquid per unit of time to
allow the operator to reach a safe distance before the explosion occurs.
Figure 2 shews in section an arrangement which may be adopted in cases where
the position and direction of the bore or blast hole are suitable.
This arrangement permits an explosive to be fired by generating a detonating
gas within the channel or channels of the tamping so that a tube or pipe leading
into such channels from outside is dispensed with. For this purpose a space H is
provided in the rock or material to be blasted and in this space the gas
generating bottle G is inserted and the part B of the bore or blast hole
situated in front of the said bottle is tightly closed by means of clay, gypsum
or other suitable material. Or instead of a separate vessel such as G where
mouldable clay or a substance, which will remain passive or inert for a con-
siderable time, is used as the tamping material a suitable chamber for the
reception of the liquid and solid gas generating substances may be cut out in
the tamping material itself. The ingredients being of such a nature or
proportioned that the explosion or ignition can be timed. The front part B₁ of
the chamber can be tightly closed or stopped up very quickly and the operator
has ample time to withdraw to a safe position before the explosion takes place.
In order to prevent the passage A (where such passage is used) becoming
either contracted or clogged, the cord or wire or the like used in forming the
said passage A is not removed till the last moment and after the filling at B'
is put in.
so
Where
Where the nature of the explosive used enables a special detonator to be dispensed
with, and where the result of the reaction between the explosive and the fluid with
which it is brought into contact is not strictly speaking detonation, the igniting
material Z intended to cause an explosion when met by the gas employed can be
applied directly to the front end of the cartridge S as shewn in Figure 2.
chlorine is used, particularly powerful igniting agents such as powdered arsenic,
antimony or bismuth, or mixtures of red phosphorus and nitrate of potash should be
employed. A still more powerfully acting mass will be obtained by mixing 3 parts
(by volume) of precipitated oxide of mercury, part (by volume) of ammonium
chloride part (by volume) of arsenic and part (by volume) of sulphur, the
reason of its intense action probably lying in the formation of hypochlorous
anhydride and chloride of nitrogen in the nascent state.
These substances may be used either as independent agents or as component parts
of well known detonators. They may be replaced (as may be also the gases or
other fluids admitted) by other substances capable of exercising a similar chemical
action either directly or indirectly; or their mechanical arrangement may be varied
without departing from the nature of my invention.
I do not claim the employment of bodies such as caustic lime or soda, which in
contact with liquids, merely produce compressed steam or compressed carbonic acid
and therefore act only by means of a gradually increasing expansion resembling
that to which the walls of a steam boiler are subjected.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed I declare that what 1
claim is-
1. In effecting the ignition of blasting charges by means such as are described
in the Specification of my former Patent No. 2341793 and also herein described the
formation of a channel or channels for the passage of the gas or other fluid to
the cartridge through the tamping material itself substantially as hereinbefore
described.

page_text: 2. In effecting the ignition of blasting charges by means such as are described
in the Specification of my former Patent No. 23417 of 1893 and also as herein
described the formation of a channel or passage or channels or passages for air
and inert gas through the tamping material itself substantially as hereinbefore
described.
3. In effecting the ignition of blasting charges by means such as are described
in the Specification of my former Patent No. 2341793 and also herein described
the formation of a channel or channels for the passage of the gas to the cartridge
through the tamping material itself and also a chamber formed in the tamping
material for the reception of the agents or the bottle or vessel containing the agents
for generating the gas to so pass to the cartridge all substantially as hereinbefore
described.
4. The means for igniting blasting charges hereinbefore described and illustrated
in Figure 1 of the accompanying drawings.
5. The means for igniting blasting charges hereinbefore described and illustrated
in Figure 2 of the accompanying drawings.
Dated this 19th day of February 1895.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents..