IMPROVEMENTS IN OR CONNECTED WITH SAFETY LAMPS, PARTS OF WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO PYROMETERS
Year: 1879

page_text: LETTERS PATENT to John Dickinson Brunton, of Leighton Crescent, in the
County of Middlesex for the Invention of IMPROVEMENTS IN OR CONNECTED
WITH SAFETY LAMPS, PARTS OF WHICH IMPROVEMENTS ARE ALSO APPLICABLE
TO PYROMETERS." A communication from abroad by Louis Gossiaux, Manager
of the Works of the Societe Anonyme des Charbonnages des Bouches-du-Rhone,
in the Republic of France.
Sealed the 18th May 1880, and dated the 21st November 1879.
PROVISIONAL SPECIFICATION left by the said John Dickinson Brunton at
the Office of the Commissioners of Patents on the 21st November 1879.
to
JOHN DICKINSON BRUNTON, of Leighton Crescent, in the County of Middlesex.
IMPROVEMENTS IN OR CONNECTED WITH SAFETY LAMPS, PARTS OF WHICH IMPROVE-
MENTS ARE ALSO APPLICABLE TO PYROMETERS." A communication from abroad by
Louis Gossiaux, Manager of the Works of the Societe Anonyme des Charbonnages
des Bouches-du-Rhone, in the Republic of France.
This Invention relates to improvements in or connected with safety lamps, and it
has for its object the construction of an apparatus which shall indicate measure and
consume a large proportion of fire damp, with a view to preventing the accidents
arising from the presence of fire damp in mines.
It has been ascertained that in the case of a safety lamp burning in a mine which
yields a permanent supply of fire damp there is generated within the wire gauze
covering of the lamp an amount of heat which is dependent upon the quantity of
gas contained in the atmosphere in which the lamp is burning. The wire gauze,
and consequently a thin stratum of air surrounding the said wire gauze, thus passes
through all the degrees of heat, from the temperature acquired when the lamp is
burning in pure air up to the temperature of red hot iron, according to the quantity
of fire damp which is present.
In carrying out this Invention, in order to effect the object before mentioned this
property of variation in the temperature according to the quantity of fire damp
present is utilized in the construction of the apparatus in the following manner:
The improved apparatus is composed of two principal parts, viz., 1st, the lamp
proper, and 2nd, pyrometer.

page_text: 1st. The lamp is provided with a cylindrical reservoir containing the oil for
supplying the wick, and having a flat bottom. A central tube is soldered to the
bottom inside the reservoir, and a second tube, fitted so as to be capable of turning
freely within the former, is provided at its upper extremity with a disc, which is
also soldered to another tube having one or more external screw threads, and sur-
rounding the tubes hereinbefore referred to. All these tubes are situate within two
other concentric tubes soldered to the bottom of the reservoir, and supporting the
wick of the lamp between them. The inner tube of the two last mentioned tubes
is provided throughout nearly the whole of its length with longitudinal slits or slots,
through which are passed a corresponding number of projections formed upon a nut
working upon the screw threaded tube, and these projections carry claws which lay
hold of the lower extremity of the wick. The wick may be raised or lowered by
the act of turning the tube carrying the disc hereinbefore referred to by means of a
button fixed on its lower extremity, and thereby rotating the screw threaded tube,
so as to cause the nut to travel up or down the said tube.
The oil reservoir is provided with a cover having a central orifice closed by a
screwed plug, the latter being formed with holes through which the oil may be
introduced into the reservoir, and which also serve to conduct any oil overflowing
from the wick back into the interior of the said reservoir.
The arrangement for snuffing the lamp when burning consists of a metal rod
working inside the central tube, and provided at its upper extremity with a small
toothed cylinder two discs. Between these discs works a sliding piece of metal,
which carries a knife and is provided with a slot having internal teeth on one
side forming a rack which engages with the small toothed cylinder hereinbefore
referred to. The slot is of such a length as to allow the sliding piece to move
laterally in such a manner that the knife may be caused to project a sufficient
distance to enable it to reach the wick for the purpose of snuffing the same, and to
enable the knife to be retracted within the wick when not in use.
By turning a button fixed on the lower extremity of the rod the sliding piece
rotates with the rod until it bears against a short pin acting as a stop, whereupon
the toothed cylinder working inside the slot causes the sliding piece to move laterally
and push out or retract the knife. In order to snuff the wick the button on the rod
is turned in one direction until the sliding piece comes in contact with the stop,
then, by continuing to rotate the rod, the toothed cylinder pushes out the knife as
far as possible; the rod is then pushed upwards by pressing the button until the
sliding piece rises over the stop, and while thus elevated the rod and knife are
rotated so as to cause the latter to remove the carbonised portion of the wick, after
which the rod is drawn downwards and turned in the opposite direction, so as to
retract the knife. When the wicks are very small the knife is arranged to act from
outside the wick.
2nd. The pyrometer employed in the lamp constructed according to this Invention
is by preference composed of a metal wire coiled in the form of a helix, and placed
between columns which prevent the diameter of the helix from changing. the wire
being caused to engage in suitable notches or recesses provided for its reception in
the sides of each of the columns: or, according to another arrangement, the wire
may be passed through holes formed in the columns; or, again. two sets of columns
may be provided, one set being arranged on the interior and the other on the exterior
of the helix, so as to support the wire between them. The columns are connected
together at their upper extremities by means of a suitable ring, and the upper
extremity of the wire forming the helix is made fast to one of the columns. The
other extremity of the said wire is free to move according to the expansion or con-
traction of the metal, and is provided with a tube closed at one end for the purpose
of adjusting the apparatus. When the metal expands the end of the tube pushes the
upper extremity of a lever, the lower extremity of which carries a small toothed
segment this segment is in gear with a pinion fast upon a horizontal spindle
carrying a pointer, which is thus caused to travel over a graduated semicircle. A
small spring is provided for the purpose of maintaining the extremity of the lever

page_text: in contact with the end of the tube. A cylindrical base is employed furnished with
a flat surface, on one side having a glazed aperture, the glass of which is maintained
in position by means of a metal frame fastened to a plate supporting the spindle of
the pointer and the graduated scale.
A ring screwed into the top of the cylindrical base serves to support the lower
extremity of a cylindrical casing of wire gauze by means of a collar formed in
segments, and attached to the said ring by screws, which cause the segments to grip
the gauze between the said segments and the internal circumference of the ring. A
second cylindrical casing of wire gauze is arranged so as to enclose the former, and
is secured in position by means of a ring screwed on to the upper part of the
cylindrical base, which ring also serves to support a suitable number of vertical
columns connected at their upper extremities to a cover provided with a ring for the
purpose of suspending the lamp. When the ring is screwed down it is prevented
from becoming unscrewed by means of a set screw situate inside the base.
The helix is arranged in the space between the two casings of wire gauze. The
employment of two casings is an extra precaution against danger, because in case of
one of the casings becoming accidentally out of order the other would still be
sufficient to afford the required protection, but one only may be used, if desired.
The lamp hereinbefore described is screwed into the lower part of the cylindrical
base, and is prevented from becoming unscrewed by means of ratchet teeth formed
on the bottom of the oil reservoir, and engaging with two pawls on the cylindrical
base arranged one above the other, and caused to press against the teeth by means
of springs. The upper pawl, with its spring. is separated from the lower one by
means of a metal plate, and the pawls may be disengaged from the ratchet teeth by
means of a suitable key, when it is desired to unscrew the lamp.
The details of the arrangements of the parts may be modified to suit the different
sizes, of lamps or the exigencies of particular cases.
In order to make the space travelled over by the pointer proportional to the
expansion of the wire of the pyrometer a rack may be substituted for the lever
hereinbefore described, such rack being actuated by the free end of the wire, and
acting upon the pinion of the spindle carrying the pointer, either directly or through
the intervention of a double toothed segment.
The apparatus hereinbefore described. when employed without the lamp, consti-
tutes a pyrometer which may be applied to any required purpose by adjusting the
graduations of the instrument to correspond with the limits of temperature to be
indicated by the pointer.
It should be observed that in carrying out this Invention the dimensions of
ordinary safety lamps are by preference increased, for the purpose of augmenting
the consumption by such lamps of the fire damp present in the atmosphere in which
such lamps are employed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Dickinson Brunton in the Great Seal Patent Office on the
19th May 1880.
"
JOHN DICKINSON BRUNTON, of Leighton Crescent, in the County of Middlesex,
Civil Engineer. IMPROVEMENTS IN OR CONNECTED WITH SAFETY LAMPS, PARTS
OF WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO PYROMETERS." A communica-
tion from abroad by Louis Gossiaux, Manager of the Works of the Societe Anonyme
des Charbonnages des Bouches-du-Rhone, in the Republic of France."
This relates to an apparatus which indicates, measures, and to a great extent
burns the fire-damp, the presence of which in mines is too often the cause of
terrible accidents, which this apparatus will effectually prevent if the indications are
acted upon.
By observing a miner's lamp burning it will be noticed that the light it gives in
mines where fire-damp permanently exists in much greater than when the same
lamp is burning in pure air, which is caused by the gas passing through the meshes
of the metallic gauze and being burnt by the flame of the lamp, and the small
quantity of oil burnt relative to the time during which the lamp is at work gives a
further proof of this fact. The greater the quantity of gas the greater will be the
intensity of the heat developed in the envelope of metallic gauze, and it may be
said that the intensity of this heat is in proportion to the quantity of gas contained
in the place where the miner's lamp is burning.
When the atmosphere is saturated with fire-damp, the heat developed in the
lamp may be so great that the metallic gauze will become red hot and set light to
the gas surrounding it, thus causing an explosion.
This shows that the metallic gauze, and consequently a small space surrounding
this ganze, passes through all the degrees of heat from the temperature obtained
when the lamp burns in pure air to the temperature of red hot iron.
It is upon this principle of variation in the temperature that this apparatus is
based.
The apparatus consists of two principal paris, viz., the lamp and a pyrometer.
The lamp consists of a cylindrical reservoir A in which the oil to be burnt is
contained. A tube b is soldered to the base B. a second tube a turns freely in the
first tube, and is terminated at its upper extremity by a disc c to which is also
soldered another tube d screwed with one or more threads. Two other tubes e and
f between which the wick is placed are soldered to the base B. The tube e is
formed with longitudinal slots made nearly the full length of the tube and serving
to allow the passage of projections on a nut g, such projections having teeth or
claws for the purpose of seizing hold of the wick at its lower extremity. By
turning a knob fixed on the lower end of the tube a the screwed tube d which is
firmly connected to the tube a causes the wick to ascend or descend as required.
A disc C screwed on the top part D of the lamp is made with openings j.
allowing the oil reservoir to be filled with oil, and also the excess of oil which
the capillary action causes to ascend in the wick to fall back again into the
reservoir.
The arrangement for trimming the wick whilst it is burning consists of a
metallic rod f, at the top end of which is fixed a small toothed cylinder o carrying
two small discs m. between which is placed a piece n formed with a slot having on
one of its sides teeth which gear with the pinion o. The length of the slot is such
that the piece n can be placed exactly in the centre of the wick when not in use
and present its cutting edge above the edges of the wick in the other position.
By turning the knob p fixed to the lower end of the rod t the piece n is stopped
by a small rod (plan) which projects but slightly, and the pinion causes it to
occupy one of its two positions. To trim the wick the piece is caused to occupy its

page_text: extreme position, then by raising the knob p the stop g can no longer act, and
then the knob p being turned, still keeping it in its raised position, the charred
part of the wick is removed. After the operation the knob is pulled down and
turned in the opposite direction so as to cause the piece n to occupy its former
position.
In the Drawing the piece is shown in the position for trimming the wick.
The wick employed is round and I claim the exclusive right of employing the
movement of a piece turning round the axis of the wick for the operation of
trimming the wick. When the wick is of very small diameter the cutting piece is
placed outside the wick.
Pyrometer. When a metallic wire wound in a spiral form is subjected to the
action of heat the wire lengthens and the diameter of the spiral increases, but if
one extremity of the wire is fixed and the diameter of the spiral invariable, the
other extremity of the wire will move either forward or backward according to the
expansion or contraction corresponding to the increase or diminution of the
temperature.
The pyrometer employed in this apparatus consists of a metallic wire wound in
spiral form and placed between the columus I (plan) which maintain the diameter
of the spiral invariable, in order to effect which the wire is lodged in cavities
formed in the length of each of the columns. The wire might also be made to pass
through holes formed in the columns, or other columns might be placed in juxta-
position to the former columns, so that the wire would be completely encased
between the two sets of columns. The columns I are connected together at their
upper extremities by a metallic ring S.
The free end of the metallic wire is terminated by a tube closed at one end.
This tube is destined to facilitate the regulating of the instrument. When the wire
expands the end of the tube pushes a lever F (elevation) terminated by a small
toothed sector gearing with a small pinion, upon which is fixed a hand moving over
a graduated semi-circular dial.
A small circle tends to keep the end of the lever F constantly in contact with
the end of the tube. A cylindrical frame is formed laterally with a flat surface in
which an opening is made to receive a piece of glass kept in position by a small
metallic border fixed to the plate H, to which the movement of the hand and the
graduated dial are secured.
This plate is maintained in position by means of small screws placed all round.
An envelope of metallic gauze is fixed to a ring J screwed internally to the top
part of the frame G by means of square sectors K which keep the gauze stretched
by means of screws. A second metallic gauze envelope is maintained in position
by the screwing up of the ring L, on the edge of which are fixed the columns N
which carry the cap M provided with a ring to receive the suspending hook.
When the ring is placed in position a screw O placed in the interior of the frame G
prevents this ring from being unscrewed.
The spiral is placed in the space formed by the two metallic envelopes. By
employing two envelopes a greater security is obtained, for should one of them
become in any way damaged the other will still maintain the desired security.
The lamp hereinbefore described is screwed to the lower part of the frame G,
and in order to prevent the miners unscrewing the lamp a safety lock is placed on
the lower part of the frame G.
The ratchet teeth Q (horizontal section) formed in the lower part of the base B
of the lamp receive the ends of the two superposed pawls R. which springs P tend
to keep engaged with the ratchet teeth. An iron plate separates each play of the
pawl and the spring. A removable barrel key acts upon the pawls and maintains
them in their extreme position when it is desired to unscrew the lamp.
This apparatus may be made in various sizes, and it will be readily understood
that the arrangement of certain parts will vary, but the fundamental principle
upon which the apparatus is based will remain the same. This principle consists
in the employment of any form of pyrometer placed so as to receive the action of

page_text: the heat developed by a miner's lamp, whether such lamp be protected by either
only one or by several metallic gauze envelopes.
If from this apparatus the lamp is removed, there still remains a pyrometer
which may be applied to any desired use by suitably graduating the instrument
according to the limits of temperature that the hand ought to indicate.
In order to obtain the graduation of the instrument the lamp is lighted in pure
air and when the hand remains stationary 0 is marked at such point on the dial.
The lamp is then removed and replaced by an iron cylinder of which the bulk is
about a fifth part of that developed by the first metallic gauze; this block of iron
is heated to a cherry red and introduced inside the envelope, leaving it until the
first envelope begins to become red, which corresponds, as already stated, to the case
when a lamp burns in an atmosphere completely saturated with fire damp. At
the position which the hand will then occupy on the dial 100 is marked, and the
space between 0 and 100 is divided into 100 equal parts. The degrees of the
instrument are thus obtained.
In order that the path traversed by the hand may be proportionate to the
expansion or dilatation of the wire of the pyrometer, the lever might be replaced
by a toothed rack which the movable end of the wire would put in motion: this
rack would act either directly or by the aid of a double toothed sector upon the
pinion which carries the hand of the instrument.
As already stated each lamp burns a small quantity of fire-damp, the large sized
apparatus would consume a very much greater quantity, and consequently the
chance of explosion would correspondingly diminish.
Having now set forth the nature of this Invention as communicated to me from
abroad, and explained the manner of carrying the same into effect, I wish it to be
understood that what I claim is,
First. Increasing to a considerable extent the volume of ordinary miners' lamps
so as to increase the combustion of the fire-damp by these lamps.
Second. The arrangement which consists in the application to this lamp of a
pyrometer based upon the principle of the expansion and the contraction of a
metallic wire in a spiral form according to the temperature to which it is subjected.
as well as that which consists in communicating these different movements of the
spiral wire to a sector of a graduated dial serving to signal the presence of any
quantity, either small or large, of fire-damp in the mine.
Third. The general arrangement of the apparatus as herein described.
In witness whereof, I, the said John Dickinson Brunton, have hereunto set
my hand and seal, this Nineteenth day of May, in the year of our Lord
One thousand eight hundred and eighty.
JOHN DICKINSON BRUNTON. (L.S.)