IMPROVEMENTS IN APPARATUS FOR PREVENTING EXPLO- SIONS IN COAL MINES, PART OF WHICH IS ALSO APPLICABLE FOR INDICATING OR CONTROLLING THE DENSITIES OF GASES OR OF GASEOUS MIXTURES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Arnold Budenberg at the Office of the
Commissioners of Patents on the 16th October 1880. A communication
from abroad by Christian Frederick Budenberg and Bernhard August Schäffer,
both of Buckan, Magdeberg, in the German Empire.
ARNOLD BUDENBERG, of the City of Manchester, in the County of Lancaster,
Mechanical Engineer.
"IMPROVEMENTS IN APPARATUS FOR PREVENTING EXPLO-
SIONS IN COAL MINES, PART OF WHICH IS ALSO APPLICABLE FOR INDICATING
OR CONTROLLING THE DENSITIES OF GASES OR OF GASEOUS MIXTURES."
A communication from abroad by Christian Frederick Budenberg and Bernhard
August Schäffer, both of Buckan, Magdeberg, in the German Empire.
This Invention has for its object the prevention of explosions in coal mines
either by giving an indication or alarm when an undue or excessive proportion of
gas is present, or by igniting the gas or gaseous mixture as it escapes from the coal
or is formed in the galleries or other parts of the mine at frequent intervals, thus
substituting a series of harmless explosions for a single great explosion, which
might otherwise result.
The first part of this Invention which may also be arranged to indicate the
presence of carbonic acid or other gases in wells, manholes of sewers, and similar
places, consists in utilizing the different densities of various gases in the following
manner:-
A closed vessel of thin sheet metal or other suitable material, and containing any
suitable gas or gas mixture, but preferably atmospheric air, is so suspended or
supported in the gas or gas mixture, the density of which is to be indicated or
controlled that the motion, deformation, or change of volume of the vessel caused by
an alteration of the density of the medium by which it is surrounded or to which it
is exposed acts upon an indicator of any known construction, for instance, an alarm
bell, preferably by opening or closing the current of a galvanic battery.
This may
be effected in the following manner:-A. light cylindrical vessel filled with air is
suspended from one end of a scale beam, and the said vessel is guided at its lower
end, preferably by means of a vertical guide pin, while the other end of the scale
beam carries a weight which is adjustable, and a needle of the scale beam is allowed
to play between two set screws, one of which is fixed insulated but connected by a
conductor with a binding screw (positive) of a conducting wire leading to a
galvanic battery, the current of which passes through the other binding screw

page_text: (negative) to the stand of the scale beam and to the needle. The instrument is so
adjusted that in the highest position of the air vessel the circuit is open, but closed
as soon as the said air vessel falls in consequence of an increase of light gases in
the surrounding medium, or it may be adjusted that in the lowest position of the
air vessel the circuit is open, but closed as soon as the said air vessel rises in
consequence of an increase of heavier gases in the surrounding medium. The
electric circuit actuates an alarm bell or causes a small explosion, and is inter-
rupted as soon as the density of the surrounding medium is restored to its normal
state.
Instead of suspending the air vessel from a scale beam, it may be suspended
from a helical or other spring and guided at the bottom by a pin which touches an
adjustable contact spring when the air vessel falls, or it may be arranged with
heavier gases that the contact takes place by a rising of the air vessel, the current
passing in this case through the stand, suspension spring, air vessel, and contact
spring.
Another modification of the apparatus is obtained by supporting the cylindrical
air vessel by a number of feet arranged at the lower part of its circumference and
closing the cylinder at top and bottom by a flexible diaphragm, preferably of
corrugated sheet metal, the top end being protected by a hood open at the upper
part and attached to the mantle of the cylinder by brackets.
The two diaphragms are connected by a central rod projecting below the lower
diaphragm and ending opposite a contact spring so adjusted that no contact takes
place when the cylinder is placed in atmospheric air, but that the lowering of the
said rod or rising, if so arranged for heavier gases caused by an alteration of the
surrounding medium, establishes a contact with the spring and thereby closes the
current of a galvanic battery.
When desired, the motion or deformation of the air vessel may be indicated on a
dial by a pointer which may be actuated by any known means, as for example, the
current of a galvanic battery.
The second part of this Invention consists in providing in various parts of the
mine electric lamps or spirals of fine platinum wire or other apparatus, which,
when an electric current is passed through it is capable of igniting gas either by
the formation of an electric arc or spark, or by incandescence. The stations and
positions of these lamps may be as numerous as required for the protection of the
mine, and as the explosive gases are lighter than atmospheric air they should be
placed near the roof. Insulated conducting wires are led from each lamp to a
central station where a series of apparatus is provided for producing, dividing, or
distributing and controlling the electric current in such a manner that it shall
actuate each lanp in the mine in succession, beginning with the first lamp, passing
through the whole series, and then commencing again, so that the gases shall be
ignited before they have time to accumulate and assume dangerous proportions.
The electric current required for the lamps may be generated by means of a
voltaic battery or by a Gramme, Siemens, or other machine as is well understood,
a wire leads from this battery or machine into the mine with a branch to each
lamp. The other wire from the battery or machine is led to a distributor, the
function of which is to divide or distribute the current to each of the lamps in
succession. From the distributor insulated wires are led to the lamps, one wire
being required for each lamp. All the wires leading to the mine may be gathered
into a cable for convenience.
The distributor consists of a shaft or cylinder of bronze or other suitable metal,
and has turned in it as many grooves as there are lamps; between these grooves are
arranged metal studs, one being between each pair of grooves in such positions
that a line passing through each stud shall describe a helix round the cylinder.
At right angles with the axis of the cylinder are fixed a series of contact springs
which are each provided at the end in contact with the cylinder with a block of
ebonite or other insulator shaped so as to work freely in the grooves. At the
same end of each contact spring is a metallic projection so fixed as not to touch

page_text: the cylinder but to come into contact with the studs, when by revolution of the
cylinder the studs are brought under the contact springs. Each of these metallic
projections on the contact springs is in metallic connection with one of the wires
leading to the lamps, and the cylinder is in netallic connection with the wire
leading from the battery or machine herein before mentioned. It will thus be
evident that for every complete revolution of the cylinder a current of electricity
will be sent to each lamp in turn, it being understood that the contact springs are
insulated from each other.
The rotation of the cylinder may be effected by weights, clock work, or in any
other manner, or by means of a special apparatus consisting of a clock, electro-
magnet, levers, ratchet wheel, and pawls, and an electric current derived from a
local battery, or from a branch from the battery or machine before mentioned in the
following manner :-
The pendulum of the clock is connected with one pole of the battery, so that
when it vibrates it may, by means of a contact piece attached to it, complete the
electric circuit by coming in contact with another fixed contact piece connected
with the other pole of the battery once for each vibration or half vibration as may
be desired. The momentary current thus produced passes through the coils of an
electro-magnet fixed upon the base of the distributor which then attracts an
armature suspended above it by means of a spring. On the cessation of the current
the spring withdraws the armature, and this operation is repeated for every contact
made by the clock pendulum. Attached to the armature is a lever pivoted at its
other end; this lever partakes of the motion of the armature and passes over a
ratchet wheel keyed on the axis of the cylinder. To the lever is pinned a pawl
taking into the ratchet wheel, so that for every stroke of the lever the ratchet
wheel advances a part of a revolution. In order to prevent a retrograde motion of
the ratchet wheel during the up stroke of the lever, a second pawl may be provided
which may be pinned to a bracket on the base board and take into the ratchet
wheel in a contrary direction to the pawl on the lever.
A galvanometer may be inserted in the circuit from the battery to the distributor,
and another in the local circuit between the clock and the distributor to show
when the current is passing, or there may be substituted for the galvanometer
or used in addition thereto an alarm apparatus to be brought into play on the
cessation of the current; this alarm apparatus may be constructed in any known
manner, or it may consist of a spiral of wire which forms part of the circuit of the
electric current by which it is expanded; so long as it is thus expanded the alarm
apparatus is not effected. Immediately however on the cessation of the current the
spiral cools, contracts, and releases a trigger which liberates a weight, the descent
of which actuates a bell or other alarm, closes a local electrical circuit which rings
an electric bell or puts an electric bell into an existing circuit.
The studs between the grooves of the distributor may be of such a length that
simultaneously with one passing out of contact with its contact spring, the succeeding
stud comes into contact with its contact spring, so that the current in the return
wire from the lamps may be continuous, when in the event of the failure of any of
the lamps the current will be intermitted and the alarum be sounded, or the
galvanometer needle will return to zero every time the faulty lamp is put in
circuit.
The distributor may be placed in the mine, in which case the cable of conducting
wires may be dispensed with.