Improved Plugging or Tamping Compound for Blasting Cartridges, also applicable for Keeping the Packages of such Cartridges Dry.
Year: 1893

page_text: Date of Application, 13th Apr., 1893
Complete Specification Left, 12th Oct., 1893—Accepted, 25th Nov., 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by WESTFÄLISCH-ANHALTISCHEN SPRENGSTOFF
ACTIEN GESELLSCHAFT, of Coswig, Anhalt, Germany, Manufacturers.
Improved Plugging or Tamping Compound for Blasting Cartridges,
also applicable for Keeping the Packages of such Cartridges Dry.
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Chartered Patent Agent, do
hereby declare the nature of this invention to be as follows:-
In blasting in mines, in particular coal mines, only such explosives could be
employed heretofore that produced no flame on their explosion, and consequently
were not liable to fire the fire damp or explosive gases collecting in the workings.
In consequence of this necessary restriction, a number of explosives could not be
used which although very effective in their blasting action yet produce flame on
their explosion and are consequently liable to cause explosions of fire damp.
According to the present invention this defect is obviated by plugging or
tamping the blast holes with the hereinafter described compound, which exercises
an extinguishing action upon flame, or at least envelopes the same in an
extinguishing layer of vapour so as to prevent any communication thereof with the
fire damp.
For this purpose the tamping or plugging for the blast hole is formed of a
cartridge consisting of a mixture of a neutral powder such as infusorial earth,
schwerspath, brickearth, fine sand &c. with a hygroscopic or liquefiable salt or a
liquid, which salt in consequence of the high temperature produced by the explosion
of the blasting charge, gives off all its moisture in the form of steam or vapour
which at the moment of firing is projected out of the blast hole so as to form in
front of the same an envelope surrounding the flame and explosion gases. The
neutral powder fulfils two purposes; firstly it prevents the hygroscopic liquid or
the liquefied hygroscopic salt from penetrating through the casing of the cartridge,
and running away, and secondly the said powder is ejected on the firing of the
cartridge in the form of a dust cloud and as each particle hereof has an envelope
of the hygroscopic liquid or salt, it will also effectually prevent contact of the flame
with the fire damp.
If only liquid were employed, without the powder, the main bulk thereof would
be ejected to a distance without being converted into a steam cloud immediately in
front of the blast hole and would consequently not have the described protective
effect.
It is also to be observed that the evaporation of the hygroscopic liquid or solution
takes place with a considerable absorption of heat, in consequence of which the
explosion gases issuing from the blast hole are reduced to a temperature which is
below that at which the ignition of the fire damp can take place.
In order to prevent that in keeping the said plugging or tamping material for a
longer time in dry air a decrease of the quantity of water contained therein shall
take place, so as to reduce the effectiveness thereof, it is essentially necessary that
only hygroscopic liquids or salts shall be employed for the above purpose.
Under these conditions the plugging material can also fulfil a further useful
purpose; it can be filled into suitable porous receptacles, that may have the form of
cartridges, together with the explosive compound, in which case it will serve to absorb
the moisture existing in the explosive cartridge and consequently to keep the latter
perfectly dry during storage and transport. In this application also is the
presence of a neutral powder of importance, as it effectually retains the hygroscopic

page_text: material and prevents it from running out of the porous receptacle in consequence
of the large amount of moisture it absorbs, and thus prevents any contact between
the liquid and the explosive.
In practice it is advisable to pack an explosive that is to be protected against
moisture, together with a number of cartridges containing for example a mixture
of 80 parts of infusorial earth and 20 parts of calcium chloride powder free from
water, or sodium bisulphate powder &c.
Immediately before use, the packet of explosive cartridges is opened, the dry
cartridges are taken out and placed in the blast holes and the cartridges of plugging
compound are then inserted in front of them.
Dated this 12th dow of 1002
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Plugging or Tamping Compound for Blasting Cartridges,
also applicable for Keeping the Packages of such Cartridges Dry.
I, CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Chartered Patent Agent, 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 :-
In blasting in mines, in particular coal mines, only such explosives could be
employed heretofore that produced no flame on their explosion, and consequently
were not liable to fire the fire damp or explosive gases collecting in the workings.
In consequence of this necessary restriction, a number of explosives could not be
used which, although very effective in their blasting action, yet produce flame on
their explosion and are consequently liable to cause explosions of fire damp.
According to the present invention this defect is obviated by plugging or tamping
the blast holes with the hereinafter described compound, which exercises an
extinguishing action upon flame, or at least envelopes the same in an extinguishing
layer of vapour so as to prevent any communication thereof with the fire damp.
For this purpose the tamping or plugging for the blast hole is formed of a
cartridge consisting of a mixture of a neutral powder such as infusorial earth,
barytes, brick earth, fine sand &c. with a hygroscopic salt or salt solution, which
salt in consequence of the high temperature produced by the explosion of the
blasting charge, gives off all its moisture in the form of steam or vapour which at
the moment of firing is projected out of the blast hole so as to form in front of the
same an envelope surrounding the flame and explosion gases. The neutral powder
fulfils two purposes; firstly it prevents the hygroscopic liquid or the liquefied
hygroscopic salt from penetrating through the casing of the cartridge, and running
away, and secondly the said powder is ejected on the firing of the cartridge in the
form of a dust cloud and as each particle hereof has an envelope of the hygroscopic
liquid or salt, it will also effectually prevent contact of the flame with the
fire damp.
If only liquid were employed, without the powder, the main bulk thereof would
be ejected to a distance without being converted into a steam cloud immediately in
front of the blast hole and would consequently not have the described protective
effect.
It is also to be observed that the evaporation of the hygroscopic liquid or
solution takes place with a considerable absorption of heat, in consequence of
which the explosion gases issuing from the blast hole are reduced to a temperature
which is below that at which the ignition of the fire damp can take place.
In order to prevent that, in keeping the said plugging or tamping material for a
longer time in dry air, a decrease of the quantity of water contained therein shall

page_text: take place, so as to reduce the effectiveness thereof, it is essentially necessary that
only hygroscopic liquids or salts shall be employed for the above purpose.
Under these conditions the plugging material can also fulfil a further useful
purpose; it can be filled into suitable porous receptacles, that may have the form
of cartridges, placed together with the cartridges of explosive compound, in which
case it will serve to absorb the moisture existing in the explosive cartridge and
consequently to keep the latter perfectly dry during storage and transport. In this
application also is the presence of a neutral powder of importance, as it effectually
retains the hygroscopic material and prevents it from running out of the porous
receptacle in consequence of the large amount of moisture it absorbs, and thus
prevents any contact between the liquid and the explosive.
In practice it is advisable to pack an explosive that is to be protected against
moisture, together with a number of cartridges containing for example a mixture of
80 parts of infusorial earth and 20 parts of calcium chloride powder free from water,
or sodium bisulphate powder &c.
Immediately before use, the packet of explosive cartridges is opened, the dry
cartridges are taken out and placed in the blast holes and the cartridges of plugging
compound are then inserted in front of them.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A compound for plugging or tamping shot holes and for keeping packages of
blasting material dry, consisting of a mixture of a neutral powder or absorbent
medium such as infusorial earth, sand, gypsum brick earth and the like, with a
hygroscopic salt or salt solution, such as calcium chloride, bisulphate of soda &c.
by means of which, on the one hand, the deterioration of blasting materials by
moisture during transport and storage is prevented, and on the other hand when it
is used as tamping, the flame on firing is surrounded by vapour produced by the
vaporisation of the hygroscopic substance which prevents the ignition of fire damp.
Dated this 12th day of October 1893.
ABEL & IMRAY,
Agents for the Applicant.