Improvements connected with Blasting in Mines.
Year: 1892

page_text: Date of Application, 19th Apr., 1892
Complete Specification Left, 19th Jan., 1893-Accepter, 25th Feb., 1893
PROVISIONAL SPECIFICATION.
Improvements connected with Blasting in Mines.
We ALEXANDER REID MOLISON of 35 Terrace Road Swansea in the County
of Glamorgan, Science Teacher and ALLAN MCLUCAS of Brecon Villa Victoria
Road Llanelly, in the County of Carmarthen, Photographer do hereby declare
the nature of this invention to be as follows:-
This invention has for its object the providing of a blasting cartridge which
shall be free from the possibility of setting fire to inflammable gases or other com-
bustables and will therefore be especially suited for use in coal mines where blasting
by gunpowder or gun cotton would be dangerous.
The invention is carried out by providing a small cylinder, tube closed at one
end, or other suitably shaped vessel of any convenient material of sufficient strength
such as cast iron, glass or carthenware. Into this tube or vessel a rod or wire of
high electrical resistance is carried and insulated so that an electric current can be
sent through it. The wire may be conveniently wound round and may be
imbedded in a rod of clay or some similar substance and one end of the wire may
be electrically connected with the vessel or shell-if the vessel or shell be made of
a conducting material-and the other end brought through in an insulating plug.
Where the vessel is made of an insulating material, of course, both ends are
brought through for connection. Water is put in the cartridge or shell nearly
filling it, leaving however sufficient room for the expansion of the water as water.
The vessel or shell is now closed by a screw stopper or in any other convenient
manner, care being taken to make it steam-tight, or in the case of glass being used
as material for the vessel or shell, it may be simply hermetically sealed. The size
and strength of the cartridge shell is adjusted to the work it has to do.
To use this water or steam cartridge after insertion in its place wires from an
electric generator are attached and a current sent through. The water is thus
heated and raised much above the ordinary boiling temperature. When the steam
tension is above the pressure the shell can withstand the cartridge explodes and
the work is effected. It will be observed that the essential feature of this invention
is the using of steam pressure for the purpose of blasting; which steam has been
generated by the heating agency of electricity in the cartridge itself. Suitable
arrangements are made to prevent accidents from overheating of the wires (which
may be made of a metal which fuses before it rises to a dangerous degree of
temperature) and also from sparking.
The current may be supplied from a dynamo or other suitable generator, and the
generator may be placed where its presence would not be dangerous.
Dated this 18th day of A wil 1900
ALEXR. R. MOLISON.
ALLAN MCLUCAS.
COMPLETE SPECIFICATION.
Improvements connected with Blasting in Mines.
We ALLAN MCLUCAS, of Vaughan Street, Llanelly, in the County of
Carmarthen, late of 35 Terrace Road, Swansea, also in the County of Carmarthen,
Photographic Artist, and EDITH MAUD MOLISON of 35 Terrace Road, Swansea
aforesaid, Administratrix to the estate of the late Alexander Reid Molison, 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:-
The object of this invention is to produce a blasting cartridge which can be

page_text: exploded without risk of firing any inflammable gases, or explosive mixtures of
gases which may be in its vicinity. The cartridges made in accordance with this
invention are therefore especially suitable for blasting in coal mines and other
places where inflammable gases or explosive mixtures of gases or vapors abound.
The cartridge is a hollow vessel nearly filled with water, immersed in which is a
wire or rod of high electrical resistance connected to a suitable source of electricity.
When a current is passed through the wire or rod, the heat developed by its
resistance will cause the water in the cartridge to boil and the expansive force of
the steam generated will burst the sides of the cartridge and disruptor-break
asunder the strata of the coal or rock in which the cartridge is embedded.
The accompanying drawing shews a section of a blasting cartridge constructed
according to this invention.
A is the outer case or shell which may be of any desired shape or conformation
and is preferably made of a brittle metal such as cast iron of a thickness and
strength according to the internal bursting pressure which it is desired to develop
before the explosion shall take place. B is an insulating plug screwing into, or in
any other manner, airtightly secured in one end of the shell A, and T T are terminals
to which are connected the ends of the resistance C which passes through the plug B
into the interior of the cartridge. The resistance C may be formed into a loop or
spiral and immersed in the water contained in the vessel, or it may be, and prefer-
ably is, embedded in a spiral groove formed in a rod of baked clay or other
refractory material D which is attached to or formed upon the insulating plug B.
The water is filled into the cartridge leaving sufficient air space to allow for the
expansion of the water by heating and if desired the wires leading from the plug B
to just below the normal water level may be made of some good conducting
material, the resistance being below the water level so that if the cartridge is
placed vertically upright the part of the wire above the water level will not burn
away. The resistance C which may be a wire or a rod, may be made of a metal
such as zinc or a metallic alloy which will fuse before it reaches a temperature
high enough to ignite the inflammable gases in the coal or other mine or place, or
it could be so arranged that the bursting of the shell destroys the wire or rod or
otherwise disconnects the circuit.
Instead of bringing both ends of the resistance C through the plug B, an eye or
the like may be cast on the interior of the shell, to which one end of the resistance C
could be connected and the shell would then form the other terminal and could be
connected up to the electrical source.
When an electric current is sent through the wire or rod C, the water in the
shell A. will be heated, and rising above the boiling point will gradually attain
sufficient elastic force to burst the shell and when embedded in coal or other rock
will cause a rupture thereof.
Having now particularly described and ascertained the nature of this said inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is —
A blasting cartridge, comprising a shell in the interior of which is a rod or wire
of high electrical resistance immersed in water and connected to an exterior source
of electricity so as to be heated by the passage of an electric current, and the water
in the shell thereby heated until the expansive force of the steam generated, rises
to the tension required to burst the outer case or shell, substantially as described
and for the purpose stated.
Doted this 10th day of LANUM 10
F. W. GOLBY,
36, Chancery Lane, London, W.C., Patent Agent for the Applicants.