AN IMPROVED PROCESS AND ARRANGEMENTS FOR EVACUATING FIRE DAMPS FROM COAL MINES IN ORDER TO PREVENT THE EXPLOSION OF SAME
Year: 1880

page_text: LETTERS PATENT to Francis Wodiczka, of Graz (Styria), in the Empire of
Austria, Authorized Mining Engineer, for an Invention of "AN IMPROVED
PROCESS AND ARRANGEMENTS FOR EVACUATING FIRE DAMPS FROM COAL
MINES IN ORDER TO PREVENT THE EXPLOSION OF SAME."
COMPLETE SPECIFICATION filed by the said Francis Wodiczka at the
Office of the Commissioners of Patents on the 10th December 1880.
FRANCIS WODICZKA, of Graz (Styria), in the Empire of Austria, Authorized
Mining Engineer. "AN IMPROVED PROCESS AND ARRANGEMENTS FOR EVACUATING
FIRE-DAMPS FROM COAL MINES IN ORDER TO PREVENT THE EXPLOSION OF SAME.'
"
The method heretofore adopted for expelling or removing fire damp from coal
mines is based on the diffusibility of gases, by which law the explosive fire damp is
rendered innoxious by mixing the same with a sufficiently large quantity of
atmospheric air introduced from the surface by an active and continuous ventilation.
By this method however the desired result is not attained, as is evident from the
many deplorable accidents arising from explosion of fire damp which are constantly
taking place.
My improved method for drawing off or removing fire damp from coal mines is
on the contrary based on another natural law of gases, discovered and proved by
Dalton. According to this law, I render explosive fire damp innoxious by the
absorption of the same in its original and natural state, and by preventing it from
becoming diffused in the atmosphere of the mines. By comparing these two inethods,
it will be evident that my method is diametrically opposed to the method (which I
may term the ventilating one) heretofore employed.
My improved method consists essentially in the separation of the explosive gases
of less specific gravity from the gases of greater specific gravity or atmospheric air
in the mines, and in the separate drawing off or removal of the lighter gases imme-
diately after their formation by a suitable exhaust apparatus, I am thereby enablde
to draw off the explosive gases by means of suitable exhaust apparatus at greater
velocity than is practicable when they are removed simultaneously with the other
or heavier gases or atmospheric air by means of the ordinary arrangements for
ventilation, and I consequently prevent an undue accumulation of explosive

page_text: mixture or fire damp and avoid explosions. From the foregoing description it will
be evident that my method consists essentially of duplex systems of ventilation,
acting simultaneously, but separately from each other, videlicet:-
One for the gases of less specific gravity, and
One for the gases of greater specific gravity, consisting chiefly of the atmospheric
air in the mines. And in order that my said Invention may be fully understood, I
shall now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings, the same
letters of reference indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawings represents a vertical section taken along
the line C, D, Figure 2, of a gas exhaust funnel for drawing off the gases, as herein-
after described.
Figure 2 is a horizontal section of the same, the section being taken along the
line A, B, Figure 1.
Figure 3 is a vertical section taken along the line E, F, Figure 2; and Figure 4
is a detail hereinafter referred to.
For the lighter gases (fire damp) I employ the peculiar gas ventilating apparatus
and the auxiliary arrangements relating thereto hereinafter described.
The gas ventilating apparatus comprises the following parts:
a. The gas chimney, which is constructed of wooden tubbing, made gas tight in
the existing air-shaft, the cross section of which chimney should be proportional to
the existing underground or mining space.
b. The main gas channel. This consists of one channel in the roof of the main
gallery, or, according to circumstances, of two channels in the two side walls of the
main gallery.
The area of this channel, or the total area of the two channels, is in either case
equal to the area of the gas chimney. The channel is connected with the gas
chimney by gas tight joints, is closed at its ends, and may be formed either by a
tight partition separating the upper part of the main gallery from the underpart, or
by introducing an air tight tube in the roof, or, when two channels are employed,
by introducing two air tubes of equal area on the sides of the roof into the channels
of the main gallery, which are cut out for their reception.
c. The side gas channel. They branch off from the main gas channel, and are
tightly connected with the latter. The number of them depends upon the number
of the side galleries, and their area varies according to requirements.
The sum of the area of all of them should be approximately equal to the area of
the main gas channel, but should not exceed it. The side channels are provided at
their ends near the corresponding main gas channel with rotating valves or
dampers, by means of which the side channels may be shut off from or placed in
communication with the main gas channel.
The side channels, which are always arranged in the upper part of the side
galleries, can be formed of wooden air tubes, square in cross section, or of sheet iron
tubes, or of grooves or channels cut out in the coal seam or in adjacent rock. In
both the latter cases a groove or channel is formed either in the gallery roof, or
preferably in a corner between the gallery roof and its wall in the coal seam, or in
the adjacent rock, and prolonged along the side gallery. In this groove a gas
tight passage is made by means of boards laid on edge, which boards are continued
to the end of the groove.
d. The branch gas channels. They extend from the side channels, and are in
gas tight communication with the latter. Their cross section varies according to
circumstances. These channels are either arranged in the coal seam or in the
adjacent rock of the corresponding gallery roof, or they consist of wooden air
tubes, square in cross section, or of sheet iron tubes, or tubes made of any gas proof
material. The object of these branch gas channels is to enable the fire damp to be
drawn off from the branches of the side galleries and from those spaces which are
not in communication with the side galleries.
e. The gas exhaust funnels. These are arranged at the closed outlets or

page_text: apertures and on other points on the gas channels where fire damp is either present
or where it is produced, or where its formation may be apprehended.
The
They consist of funnel shaped vessels composed of sheet iron of various sizes. The
cone and neck combined together form the funnel a, b, of the Drawing.
height or elevation of the cone, and the length of the neck of the funnel, should
correspond with the diameter of the upper opening of the cone, which may be made
from, say, three to six inches.
When the exhaust funnel is to be put in communication with the cylindrical
channels, made of sheet iron or other solid materials, its neck may be shorter, but
when wooden gas channels are employed it should be longer, because in the latter
case the neck has to be introduced into holes bored in the walls of these gas channels,
as will be hereinafter described.
The area of the neck of the funnels should be at least equal to the sum of the
area of the whole of the holes, which are formed in a movable cover d, with which
the funnel is provided. To the upper circumference of the cone of the funnel is
fixed a sheet iron cylinder c, Figure 1, of, say, about three eighths of an inch in
height, which is closed by the cover d turning on a pivot e. Opposite the pivot on
the cover is fixed a clamp f, which is fitted over an eye g soldered to the cone of
the funnel, the parts being secured by a pin.
The slightly convex cover is made sheet copper or brass of suitable thickness,
and is perforated with a large number of small holes, after the manner of a rose
jet. These holes serve for the admission of the fire damp or other lighter gases
into the exhaust funnel, whence they pass to the gas channels. There is also in
the cone of the funnel an upper and a lower compartment formed by a loose iron
disc or partition h therein (see detail, Figure 4), the said disc or partition being
perforated with large holes, and made of a diameter equal to that of the central
portion of the cone of the funnel. This arrangement is designed to regulate in a
suitable manner the admission of gases into the exhaust funnel by introducing
porous substances, such, for example, as cotton, wool, and the like, into the upper
compartment of the funnel. The closure of the exhaust funnel from the gas
channels is effected by a valve i. The connection of the exhaust funnels with the
gas channels is made,―
First. In wooden gas channels, either by the introduction of the necks of the
exhaust funnels at a depth of, say, one or one and a half inches, into the holes
which are bored in the walls of the gas channels. For the fastening on the head
piece or end I solder on the necks of the exhaust funnels sheet iron shoulders K,
engaging with clamps which are screwed or driven into the walls of the gas
channels.
Second. In sheet iron gas channels. In this case the exhaust funnels are
soldered or fastened in any other suitable manner over the holes of the sheet iron
tubes.
Third. In case the gas channels consist of a different material from those before
mentioned, I effect the connection between the exhaust funnels and the gas channels,
videlicit, the fastening of the former in the holes of the latter by means appropriate
to the material of which the channel is made.
In addition to the foregoing arrangements I require,-
f. A fan (ventilator) which should be sufficiently powerful to enable a velocity of
from at least thirty or sixty feet per second to be obtained for the absorption of the
gases; and
g. A steam engine or other suitable motor for the fan.
Other additional arrangements for carrying out my system consist in the
maintenance of the fire damp or explosive gases in their natural state, and for the
prevention of an admixture of such gases with the atmospheric air in the mine.
They consist of—
a. Intercepting gas spaces, videlicit.
First. Hollow spaces formed in the roof of the gallery.
Second. Blind shafts or upbrows.

page_text: Third. Any open spaces which may remain in the grooves formed in the roofs of
the galleries after the side gas channels have been placed in position.
Fourth. All those spaces in which the fire damp or explosive gases have a
tendency to accumulate, and from which the access of the atmospheric air can be
excluded.
The fire damp or gases accumulated in such spaces can be easily and completely
drawn off by the gas exhaust funnels:
b. Of horizontal or ascending gas channels in old workings. These can be
established along the course or direction of the bed where the cogging is effected
with the employment of broken stones. In this case the gases from the old
workings pass away through channels constructed as herein before described, into the
higher levels, being drawn off by means of exhaust funnels; but when the roof is
allowed to fall in where the filling up or cogging of the old working is effected with
a material which does not consist of broken stones, the drawing off of the gases or
fire damp cannot be effected in the before mentioned manner, because the formation
of the channels would be too costly. In this case I prefer to draw off the explosive
gases (entering from the old working into the new working directly) by exhaust
funnels. It will be necessary at the same time to exclude the air from the old
working, in order to keep the gases contained therein in their natural state, and
prevent the formation of explosive mixtures.
II. For the heavier gases or atmospheric air
I employ the ventilating system or blast for the gases of greater specific gravity
in the manner which is now generally adopted and used, videlicit, I introduce
either a natural air draft, or I establish an artificial mechanical ventilation.
With regard to the velocity which the air has to receive, it will be preferable to
choose a feeble current or draft of from, say, two to three feet per second.
With regard to the direction to be given to the air, it will be indifferent whether
the current takes place in the same or in an opposite direction to that of the explosive
gases, because in both cases the action of each of the ventilating systems will be
carried out independently of each other.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion that what I consider to be novel and original and
therefore claim as the Invention is,―
The new or improved process and apparatus for removing explosive gases or fire
damp from coal mines in order to prevent explosions, by the separation from each
other of the gases found in coal mines, videlicit :-
a. The explosive gases in their pure state or mixed with other gases; and
b. All other innoxious gases (principally the atmospheric air), the explosive gases
being removed by absorption, and the innoxious gases by a ventilation or blast, all
substantially in the manner hereinbefore described.
In witness whereof, I, the said Francis Wodiczka, have to this my Complete
Specification set my hand and seal, this Thirtieth day of November,
One thousand eight hundred and eighty.
FRANCIS WODICZKA. (L.S.)