Presence of Fire-damp in Mines.
Year: 1885

page_text: Presence of Fire-damp in Mines.
:
I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co Patent Agents
Southampton Buildings in the County of Middlesex, do hereby declare the nature
of my invention for "IMPROVEMENTS IN AND RELATING TO APPARATUS FOR
INDICATING THE PRESENCE OF FIRE-DAMP IN MINES" to be as follows:-
This invention relates to apparatus for automatically indicating the presence of
fire-damp in mines, and comprises various improvements in apparatus of the class
described in the specification of former Letters Patent dated 1st August 1882
N° 3644.
r
"
One object of the said invention is to provide for effecting by means of electricity
the ignition of the fire-damp within the space enclosed by the wire gauze of the
lamp; box or chamber. For this purpose I employ in combination with the said
lamp, box or chamber suitable means for producing an electric spark or for
rendering a platinum wire or other conductor incandescent.
The said invention is moreover designed to provide, more efficiently than
heretofore, for indicating the height of the explosive gas from the bottom or floor
of the mine or gallery.
It, has been found that, whilst in some portions of the mine, the indications given
by the apparatus as heretofore constructed show the presence of explosive gas, in
other parts, no such indication is made, until the instrument is lowered to the
distance of about a foot from the roof, when the indication is at once made. This
demonstrates clearly that at some points the uppermost layers of the gas, four or
five inches from the roof, are in an explosive state, whilst at other points the gas is
not explosive for about a foot or more from the roof. The instrument or apparatus
should therefore be so arranged as to extend throughout the whole depth of the
space in which the gas is liable to accumulate so that the indications will be given
no matter what portion of the gas stratum is explosive.
1
For this purpose the indicator is graduated so that the officers in charge of the
mine shall receive the exact information not only as to the locality but also as to
D

page_text: the height of the explosive gas. The said instrument is divided into compartments
which correspond with a scale arranged on instruments of precision. And this
point has its importance; because if the farthest box or boxes should show from
the topmost compartment gas of an explosive character in that locality and very
close to the roof it might not be necessary to interrupt the work going on, a
warning to the workmen to be careful or to avoid that portion of the mine
altogether sufficing perhaps. If it were merely announced, however, that explosive
gas is present there, without an exact intimation as to its height, prudence would
immediately command an immediate cessation of work until the gas was removed.
The apparatus comprises a box or trough which is semi-circular or V-shaped in
transverse section, and the cover of which is provided with circular orifices say
about six inches in diameter. These orifices are covered with double walls of wire
gauze separated from each other by a space of about half an inch. These wire
gauze wall are protected from injury (by falling coal for example) by a perforated
shield of cast iron or other suitable metal. The instrument is placed in the mine
in the vertical position in an excavation prepared for its reception in the wall. It
is thus out of the way of falling coal, and does not occupy any of the room space of
the mine, and is not in the way.
The interior of the box or trough is subdivided into compartments. It is by
means of these compartments that the stratum of gas is tested in the various
portions of its thickness or height and the information furnished to the officer in
charge, as above stated. In each compartment is arranged a circuit making and
breaking device in combination with a thermostat, that is to say, a piece of metal
readily expansible by heat. This piece of metal is arranged as described in the
said former specification.
In mines of great extent having numerous galleries, it may be desirable for many
reasons that the arrangement be somewhat different from the preceding, that
instead of an individual box, a whole gallery or block, (according to the arrange-
ment,) should be tested at once. To accomplish this result all the boxes in the
gallery or block are placed upon one circuit, and the pressure of a button will at
once test the whole section. When this arrangement is adopted the instrument in
the interior of the box is somewhat different from that above described.
In each of the compartments of the box or trough are two terminals or points
with a slight space between them. These points are included in the circuit of an
electric generator, which circuit can be completed by pressing a button or by other
suitable means.
When it is desired to test any box the officer or engineer presses the said button
so that a current is sent along the wires to the box and a spark created between
the said points in each of the four compartments. If there be gas present in any
of the compartments, it will be exploded by the said spark; this explosion causing
a rise of temperature in the compartment brings the thermostat into action. By
the thermostatic arrangement, the indicator circuit is closed and the current
returns along the return wire connecting with the register or indicator in the office.
A double signal is given, the first the number of the box, the second the number of
the compartment. Thus if the box be No. 6 and the compartment the 3rd, in which
the explosion occurred, it will give first the number of the box by six strokes of the
bell then the number of the compartment by three strokes of the bell.
Or the indications are made upon a double register, that is to say, one having
two divisions one for the box numbers, and one for the compartment numbers.
There will be as many box numbers as there are boxes in the mine. The.
compartment numbers will be from one to four. The indications are made by a
number dropping in the box division and another number in the 2nd division or
that for the compartment numbers.
Where the boxes are arranged on one circuit for a whole gallery or block the
indication on the register is made in a similar manner only instead of showing the
number of the box it shows the number of the gallery or block. In this arrange-
ment there are no box numbers but only the numbers of the blocks or galleries.

page_text: "
As the gas, if present, is always found close to the roof and in the seams and
crevices of the same, the box as far as the level of the 1st compartment (that is
the topmost) is placed in the roof, that is to say, an excavation is made in the
roof of sufficient size, and into this the box is pushed as far as the floor of the
1st compartment.
To further the flow of gas in this direction grooves or gutters are cut into the
roof of the mine with an upward inclination and made to converge towards the
box. By these gutters the gas will naturally flow into the compartment and
whenever the boxes are tested it will be immediately shown whether the gas is
explosive or not.
It is evident from what has been stated above that when a mine is fully equipped
with the electric fire damp indicator above described the officer or officers in charge
are in position to be at all times accurately informed as to the condition of the gas
therein, its locality, its height; and its explosiveness.
There is another and very important advantage that will be derived from the
use of the electric fire damp indicator in mines, namely, that it will indicate the
presence of combustion, if such be going on anywhere although concealed.
Fires in mines are not of infrequent occurrence, and are often so destructive that
whole valuable properties are totally destroyed, or immense damage entailed. It is
not necessary to go into the details here as to the cause and manner of occurrence
of these fires; it is sufficient to state that they are of slow growth, and that their
development and breaking forth are matters that take time, perhaps years. During
this process of growth; and whilst as yet concealed and ordinarily imperceptible, it
is certain that the temperature in the immediate vicinity is raised. Now, this
elevation of the temperature acting on the thermostat causes a closure of the
circuit and an announcement at the office. Such an uncalled for announcement
will be a sufficient notice to the officer in charge that there has been a rise of
temperature in the vicinity of the box sending it, and that there is therefore good
reason for an investigation, and such investigation will be so much easier since the
locality where it has to be made is indicated by the apparatus.
Instead of employing the two points in connection with the electric generator,
I sometimes use a piece of platinum wire or other suitable conductor which will
be rendered incandescent by the electric current when the aforesaid button is
depressed or pushed in.

page_text: Presence of Fire-damp in Mines.
I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings in the County of Middlesex, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement :-
This invention relates to apparatus chiefly designed for automatically indicating
the presence of fire-damp in mines, and comprises various improvements in
apparatus of the class described in the specification of former Letters Patent
dated 1st August 1882, N° 3644.
In the apparatus described in the said former specification it is necessary to keep
a light burning in each box or chamber, in order that the fire-damp within the
same should be ignited to make or break the electric contact; and no completely
efficient means are provided for indicating the height of the explosive gas from the
bottom or floor of the mine or gallery, so that, whilst in some portions of the mine,
the indications given by the said former apparatus show the presence of explosive
gas, in other portions thereof no such indication is made until the instrument is
lowered to the distance of about a foot from the roof, whereupon the indication is
at once made. This fact demonstrates clearly that, at some points the uppermost
layers of the gas, say four or five inches from the roof, are in an explosive state
whilst at other points the gas is only explosive at about a foot or more from the
roof.
i
The objects of the present invention are firstly to provide for effecting, by means
of electricity, the ignition of the fire-damp within the space enclosed by the wire
gauze of the box or chamber, and secondly to so arrange the instrument or
apparatus that it shall extend throughout the whole depth of the space in which
the gas is liable to accumulate, and thus indicate what portion of the gas stratum
is explosive.
In carrying out the first object I employ, in combination with the said box
or chamber, suitable means for producing an electric spark or for rendering a
platinum wire or other conductor incandescent. To accomplish the second object
the instrument is divided into compartments which correspond with a given scale;
and this point has its importance, because if the box or boxes in the most remote
parts of the mine should show from the topmost compartment gas of an explosive
character in that locality and very close to the roof, it might not be necessary to
interrupt the work going on, a warning to the workmen to be careful or to avoid
that portion of the mine altogether sufficing perhaps. If it were merely announced,
however, that explosive gas were present there, without an exact intimation as to
its height, prudence would immediately command an immediate cessation of work
until the gas was removed; with this arrangement, however, the officers in charge
of the mine can receive the exact information not only as to the locality, but also
as to the height of the explosive gas.

page_text: Apparatus suitable for carrying my improvements into practice is illustrated in
the accompanying drawing, in which
Figure 1 is a front elevation of the box divided into chambers in which the fire-
damp is ignited, some parts being removed to show the interior.
Figure 2 is a front elevation of the gauze wall of one of said chambers, with its
protecting cover.
Figure 3 is a view of an indicator which may be used in combination with the
.said box.
Like letters of reference indicate corresponding parts in the several figures.
a is a box or trough which is semicircular or V-shaped in transverse section, and
which is formed into a number of compartments by partitions b. Each of these
compartments is provided with an orifice c which is covered with a double wall d
of wire gauze, the sides of said wall being separated from each other by a space
of about half an inch. This double wall is preferably formed of a ring e having
pieces of wire gauze upon its sides so that the thickness of the ring is between
them. The said walls may however be formed in any other suitable manner.
These wire gauze walls are protected from injury (by falling coal for example) by
a perforated shield ƒ of cast iron or other suitable metal, which shield, as shown;
is hinged to the ring e.
In each compartment is arranged a circuit making and breaking device ġ in
combination with a thermostat h, that is to say, a piece of metal readily expan-
sible by heat. This piece of metal is arranged as described in the said former
specification, to close an electric circuit when the temperature within one of the
compartments is raised owing to the burning of the fire-damp.
In each compartment of the box are also placed two terminals or points i i with
a slight space between them. These terminals are included in the circuit of an
electric generator, which circuit can be completed by pressing a button or by other.
suitable means.
Instead of employing the two terminals or points in connection with the electric
generator, I sometimes use a piece of platinum wire or other suitable conductor
which will be rendered incandescent by the passage of an electric current.
As the gas, if present, is always found close to the roof and in the seams and
crevices of the same, the box, as far as the level of the floor of the 1st compart-
ment (that is the topmost), is placed in the roof, that is to say an excavation is
made in the roof of sufficient size, and into this the box is inserted.
To further the flow of gas in this direction, grooves or gutters are cut into the
roof of the mine with an upward inclination and made to converge towards the
box. By these gutters the gas will naturally flow into the excavation and when-
ever the boxes are tested it will be immediately shown whether the gas is or is not
explosive.
Each of the boxes hereinbefore described is placed in an electric circuit which
may extend to any suitable point, for instance to the office of some official above
ground, and is adapted to be closed by a push button or other suitable means.
When it is desired to test any box, the officer or engineer presses the said button
so that a current is sent along the wires to the box and a spark created between
the said points ii in each compartment or the wire rendered incandescent. If
there be gas present in any of the compartments it will be exploded by the said
spark, or owing to the incandescence of the wire. This explosion causing a rise of
the temperature in the compartment brings the thermostat h into action. By the
thermostatic arrangement, the indicator circuit is closed and the current returns,
along the return wire connecting with an indicator in the office.
>
When a number of boxes are arranged in different galleries of a mine I provide
each box with means for indicating its location, for instance with means similar to
those described in the said former specification, where a bell is struck a certain
number of times. In the present instance, however, it is necessary to give a
double signal, the first being the number of the box, and the second the number of
!

page_text: the compartment of the box. Thus if the box be N° 6 and the compartment
the 3rd in which the explosion occurred, it will give first the number of the box
by six strokes of the bell, and then the number of the compartment by three
strokes of the bell..
I prefer however that the indications should be made upon a double register,
that is to say, one having two divisions, one for the box numbers, and one for the
compartment numbers, as shewn in Figure 3.
This apparatus must be provided with as many box numbers as there are boxes
in the mine. The compartment numbers will be from one to four. The indications
are made by a number dropping in the "box". division and another in the 2nd
division, or that for the "compartment" numbers.
Where a number of boxes are arranged on one circuit in a single gallery or
block the indication on the register is made in a similar manner, only instead of
shewing the number of the box it shews the number of the gallery or block. In
this arrangement there are no box numbers, but only the numbers of the blocks or
galleries.
k, kare the buttons for closing the circuits of the instruments in different
galleries..
It is evident from what has been stated above, that when a mine is fully
equipped with the Electric Fire-Damp Indicator, above described, the officer. or
officers in charge is or are in a position to be at all times accurately informed as to
the condition of the gas therein, its locality, its height and its explosiveness.
There is another and very important advantage. that will be derived from the
use of this electric fire damp indicator in mines namely, that it will indicate the
presence of combustion, if such be going on anywhere although concealed.
Fires in mines are not of infrequent occurence, and are often so destructive that
valuable property is totally destroyed, or immense damage caused. It is not
necessary to go into the details here as to the cause and manner of occurence of
these fires; it is sufficient to state that they are of slow growth, and that their
development and breaking forth take considerable time, perhaps years. During
this process of growth and whilst as yet concealed and ordinarily imperceptible, it
is certain that the temperature in the immediate vicinity is raised. Now this
elevation of the temperature, acting on the thermostat, causes the closing of the
circuit and an announcement at the office. Such an uncalled for announcement
will be a sufficient notice to the officer in charge that there has been a rise of
temperature in the vicinity of the box sending it, and that there is therefore good
reason for an investigation, and such investigation will be so much easier since the
locality where it has to be made is indicated by the apparatus.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-
:-
First. In apparatus for indicating the presence of fire-damp in mines, the com-
bination with a chamber wholly or partially covered with wire gauze, of means for
producing an electric spark or causing the incandescence of a wire or the like in
said chamber, and means operated by heat to close an electric circuit, for the
purpose specified.
Second. The method of indicating the thickness of a stratum of fire-damp,
consisting in the arrangement of two or more ignition chambers at different
elevations, and capable of acting quite independently of each other, each of said
chambers containing means for igniting the gas therein, and for enabling the heat
generated by the explosion to close an electric circuit.
Third. A box or receptacle having two or more superposed chambers, each of
which communicates with the exterior atmosphere through a wall of wire gauze,
and is provided with means for igniting the gas therein, and with a thermostat

page_text: which is caused, by the heat generated by the explosion, to close an electric circuit,
substantially as, and for the purposes, specified.
Fourth. The combination with the wire gauze walls of the ignition chamber, of
the perforated cover, for the purpose specified.
Fifth. The arrangement of the ignition box or receptacle in the roof of a gallery
in such a manner that the floor of the uppermost compartment is level with the
said roof, as set forth.