Year: 1886

page_text: Date of Application, 23rd Oct., 1886
Complete Left, 23rd Aug., 1887
Complete Accepted, 23rd Dec., 1887
JAMES MACNAB, of 39 Mortimer Street, Cavendish Square, in the County. of
Middlesex, Engineer do hereby declare the nature of my said invention to be as
follows:-
My invention relates to improvements in safety-lamps for coalmines and other
purposes by which absolute safety and efficiency under all conditions of the carburetted
hydrogen or fire-damp of the mine is secured. A more brilliant light is also produced
and which advantages have never hitherto been obtained in any previous lamp
constructed for this special purpose. It will also indicate the least fire-damp with the
utmost reliability, and consists of an entirely new departure from the principles of
the ordinary "Davy Safety-lamp" for testing gas, and embraces other novel features
which have never been introduced before into such lamps to ensure perfect safety
under all conditions of the mine. The peculiar arrangements or method of constructing
my safety-lamp is entirely independent of electricity and therefore most economical
and cheap, and in which ordinary oil, a candle, or other suitable light may be used,
although in certain special modifications I employ the electric light in combination
with my improved lamp, especially where I require to combine my novel fire-damp
indicator for testing purposes. One or more of these improvements may also be
added to the present safety-lamps, if desired, for special work where absolute safety is
not an object but where a good light is an advantage. These improvements are also
applicable for gunpowder mill lamps, magazine lamps, ship lamps, and even for
domestic use and other suitable purposes.
Where the safety arrangements or attachments are not necessary, such as in
metalliferous or other mining, it may be dispensed with.
My improvements consist in constructing safety-lamps in which water or water
slightly diluted with sulphuric acid to prevent evaporation of same, or other suitable
transparent liquid is employed, for the purpose of preventing the flame or light of
same from igniting the gas of the coalmine and also for extinguishing the light
should the glass holder or vessel be accidentally broken, & in which water or liquid
the light floats on the surface securely placed in a buoyant vessel, or may, if desired,

page_text: ne nade fixed, so long as the vessel is in contact with the surrounding water or liquid.
For this purpose a suitable quantity of water or liquid is placed in the bottom of a
glass vessel or lampholder and which is securely closed at the bottom water-tight but
open at the top, and by preference of an elongated square form with parallel sides, or
it may be cylindrical shaped, if desired, and of a suitable height to allow the light to
freely and safely burn; to support the combustion of the flame a channel or tube is
securely fixed into the wooden plug or stopper which closes in the top of the glass
vessel or lamp, and is made water-tight-this inlet air channel or tube is bent to a
right angle at the inner end or nozzle to admit of the air supply being directed on
the light; immediately above this orifice a very fine tube projects horizontally from
this main inlet air tube, and is screwed in or fixed into same, and adjusted directly
above the flame, but not in contact, for the purpose of leading down the fire-damp
which will harmlessly fire at the flame when testing for gas, and will instantly cease
to burn on withdrawing the lamp from the gas-charged atmosphere. This constitutes
the fire-damp indicator. Above, and in a line with the flame, a central outlet air
tube is placed in the wood plug or stopper of the lamp glass; to this tube is attached
short length of india rubber tubing to hang down & is weighted with a piece of
metallic tubing, and serves as a ventilating shaft, and through which the heated air
passes after it is generated by the heat of the light in the vessel floating in the
water.
This vessel has a cork or other suitable disc sealed or fixed on its bottom to assist
floatation and in which four or more projecting arms of wire or wood splints radiate
from same into each corner of the glass vessel or lamp, to keep the light-vessel in a
central position or from oscillating too freely. On the exterior top of the wood plug
or lamp stopper, and in communication with the outer ends of the air inlet and air
outlet tube orifices and connected by a short length of india rubber tubing are two
glass safety vessels one of which is attached to each air orifice; they are made of
tubing, by preference of glass, & have a bulb or circular vessel blown in the middle
while the tubes are horizontal and lead from the bulb and suitably bent to an upward
right angle, then again bent to another right angle towards the bulb, the opposite
corresponding tube is bent in a similar manner with the orifices looking towards each
other; on each orifice or end is placed a suitable length of rubber tubing, one end
being attached to the air inlet to guide down the air into the lamp, while the other
length of rubber tubing hangs downwards and is weighted with a piece of metallic
tubing to keep it in position and serves as the inlet air orifice. The corresponding
vessel or bulb and tubing is attached to the outlet air orifice or ventilating tube in a
precisely similar manner.
Previous to fitting on these bulb vessels they are charged with water, or water
slightly diluted with sulphuric acid, to prevent evaporation, to about the level of the
tubing bore; there is also placed in these bulbs a small circular cork float with a pin
or wire pendulum to steady it and to prevent the float from closing the bulb orifices
unless under a great abnormal and abrupt pressure of air or an outburst of
gas.
These bulb vessels are securely fixed at right angles to each other and the projecting
tubes are adjusted to correspond with the four sides of the glass case or interior
division of the lamp, and which has an outer or exterior glass vessel, but circular in
shape to thus form a dioptric lens, and is also charged with water, or water slightly
diluted with sulphuric acid, or other suitable transparent liquid, and is filled up to
within about two inches of the top; and which vessel is also suitably closed in water-
tight with a hollow plug or stopper of wood made to fit round the neck or top of the
lamp glass.
This plug has a small opening bored through it and is firmly covered on the top
with an outward working valve of rubber to relieve any pressure that might be
generated by the interior heat, and so let off any vapour. The square lamp-glass
vessel containing the floating light is placed down or submerged in the water of this
outer or exterior glass vessel to within a short distance of the bottom and kept
suspended in this position.
This outer vessel or skin of water now serves an important two-fold purpose.

page_text: First-it serves as a dioptric lens to magnify the light and widely distribute its rays
and thus largely increase its illuminating power. Second-it serves to protect the
lamp or inner glass vessel from being accidentally broken, and in the event of this
outer skin or medium of water being broken the inner glass skin or lamp glass will be
uninjured, and the light will still continue to burn; or should both vessels of water
be accidentally broken the outer case of water will flow in and extinguish the light in
conjunction with the inner medium of water; or should the inner glass of the lamp
be broken the outer water will instantly flow in and extinguish the light.
In the event of the lamp being upset or falling on either of its sides the light will
also be extinguished, because the water acting in the bulbs on the top of the lamp
frame comes into play and abruptly closes both the air inlet and the air outlet orifices
by flowing into the side tubes and at once stops all communication with the outer air
and the light is thus put out.
As another and most important example of safety whereby the light is instantly
blown out in the event of a sudden outburst of gas rushing at a high velocity and
striking the lamp, the great pressure alone on the air which the tubes and bulbs
contain will serve to blow out the light before the gas can penetrate to the flame,
combined with the assistance of the water and cork floats in the bulbs.
These main glass vessels, constituting the lamp and charged with water or other
transparent liquid, are suitably protected from damage by being encased with non-
conducting material and which outer case or frame is made square at the base to
correspond with the inner square glass vessel to enable the bulb or water vessels on
the top to act efficiently should the lamp be thrown by accident on its side. The top
is suitably covered in and a handle is attached for carrying the lamp in the usual
manner. These improvements, especially the water lens and fire-damp indicator can
be combined with electricity or the electric lamp as now made, whereby greater
safety, efficiency, and reliability can be obtained than at present exists, in consequence
of the water lens so largely magnifying and distributing the light over a greater area,
as considerably less battery power is required, and would therefore keep down the
great weight of necessity attached to an electric lamp.
This combination could be easily and simply made by placing and securely fixing
the electric lamp in the bottom of the inner glass vessel or lamp and filling up the
water around it, when the light-vessel could float above it, as already described, to
act as a fire-damp indicator. The incandescent glow lamp would then be inverted,
that is, the wires or conductors would run through the base or bottom of both water
vessels which have suitable necks to bind them water-tight with a piece of india
rubber tubing, and thence into the battery which is situated at the base of the lamp
proper.
For absolute safety and efficiency in the event of both the glass water vessels being
broken and to instantly cut off the electric current, I make the connections with two
glass tubes, sealed or cemented to the base of the incandescent lamp, and which are
filled with acidulated water, or other suitable conducting liquid into which the
projecting terminals or wire ends of the lamp are placed a short distance down into
the bore of the glass tubes at the top while the wire terminals of the battery project
into or pass up a similar distance into the lower or opposite extremity of these glass
tubes.
The acidulated water acting as an intervening liquid conductor, in the well-known
manner, but in this instance, and for absolute reliability in severing the connection
should the outer glass vessel be broken, the glass tube or tubes will also be broken
and instantly disconnect the current, while the upper floating light will at same
instant be extinguished by the water on which it floats in conjunction with the safety
bulbs of water on the top of the frame of this combination electric and ordinary light
safety lamp.
As a further modification of this combined electric lamp the fire-damp indicator or
glass tubing apparatus and connections may be fitted or sealed into the the glass bulb
of the electric glow lamp liquid-tight. In which case the tubing may be of a very.
fine bore, the interior end of the air inlet tube of which is bent to a right angle and

page_text: fixed into the side of the glass bulb or vessel directly opposite and suitably near to
the non-conductor film or bridge of the incandescent glow flame to enable it to
ignite the fire-damp and indicate the presence of same; while the oulet air tube or
ventilator is fixed or sealed into the top of the glass bulb in a similar water-tight
manner, when both tubes are then fixed down on the top of the lamp frame as
already described. It will then act in a similar manner and is so sensitive that it
will indicate the least amount of fire-damp or gas in the atmosphere of the mine.
Should it be desired to make the outer glass vessel of water of the lamp square instead
of round the inner glass vessel or lamp proper should be round to utilize the
advantage of the liquid lens principle; but the method already described is the most
efficient. Parts of these improvements are also adapted for domestic oil lamps,
lanterns, or where candles or gas is used, to ensure safety and also to give a greatly
increased illuminating power through the action of the water or other suitable
liquid lens.
Dated this 23rd day of October 1886

page_text: 1, JAMES MACNAB, of 39, Mortimer Street, Cavendish Square, in the County of
Middlesex, Engineer, 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 :-
This invention relates to improvements in safety-lamps for employment in collieries
and for other purposes, parts of the said improvements being adapted for use with
domestic and other lamps and lanterns in which a hydrocarbon illuminant or electricity
is employed. The objects of the said invention are to prevent or greatly diminish the
risk of the inflammable gases or combustible matter with which the atmosphere may
be charged becoming ignited from the lamp; to enable the presence of fire-damp to
be detected with greater certainty than hitherto, to increase the illuminating power,
and to provide means whereby the flame or incandescent filament may be extinguished
or cooled in the event of the glass vessel or vessels surrounding the same being
broken.
In a lamp constructed according to this invention, the flame or other source of
illumination is surrounded by water, or water to which a small proportion of sulphuric
acid or its equivalent has been added for the purpose of diminishing evaporation, or
by some other suitable transparent liquid; the same serving to quench the flame or
cool the incandescent filament, in the event of serious accident to the lamp; the
ignition of fire-damp or other inflammable atmosphere which may be present being
thereby guarded against.
And in order that my invention and the mode of carrying it into effect may be
readily understood, I will proceed to describe the same with reference to the
accompanying drawings
Figure 1 is a sectional elevation of my improved safety-lamp as adapted for
burning oil or other suitable hydrocarbon, Figure 2 being a section on the line X-X
and Figure 3 a section on the line Y-Y, Figure 1. a is the burner carried by the
reservoir a'; the latter being arranged to float on the surface of a liquid, the requisite
buoyancy being imparted thereto by means of a cork or other float a². The burner a
is maintained in a central position by means of a suitable number of wire or other
projections attached to or forming part of the reservoir a¹. A fixed burner may,
however, be employed instead of the floating one above described. The burner is
surrounded by two vessels of glass 6 6¹, arranged one within the other, the inner one
being square and the outer one cylindrical in shape, the intervening space or spaces
serving for the reception of water or other transparent and fire-extinguishing liquid.
The upper end of the cylindrical vessel 6' is closed by a plug 62, provided with valves b³
to perinit of the escape of any vapour or gas which may be evolved from the liquid
contained in the vessel. The plug 63 and the bottom of the lamp may be formed from
metal, wood or vulcanite and may be held together by means of binding rods c; the

page_text: joints between the glass vessels and the top of the lamp being made water-tight by
means of sheet india-rubber or its equivalent. The bottom of the lamp is preferably
surrounded by a brass band d, a square hollow cover e being attached to the top,
a hook or handle e¹ being added. The cover also serves to protect those parts of the
lamp, hereinafter described, through which pass the air-supply and the products of
combustion respectively. The inlet air-tube f is preferably formed of glass tubing,
and is provided at its lower extremity with a nozzle f, adapted for directing the air-
supply to the flame of the lamp. At its upper extremity it is connected, by means of
a length of flexible tubing i, with a safety-bulb f, partially charged with mercury or
with a liquid of a character similar to that within the space between the two glass
vessels 6 and 6. The safety-bulb f is blown in the middle of a pipe f³, the two
extremities of which are bent into a series of right angles, as indicated in the
drawings. The outlet pipe f*, for the escape of the products of combustion, is also
connected by means of a length of flexible tubing with a similar safety-bulb f³,
blown in the pipe f, the latter being arranged at right angles to the other pipe f³.
Each safety-bulb may be provided with a small spherical cork float f, fitted with
a wire pendulum f³, to promote steadiness of action. These safety-bulbs may be
mounted either on the plug f closing the vessel b, or in the cover e. A length of
india-rubber tubing, weighted with a piece of metal tubing it, may be attached to
the outlet pipe inside the lamp, and to the extremities of the air inlets and outlets
within the cover e; then, when the lamp is overturned, these weighted tubes become
bent under the influence of gravity, and close or partially close the communication
through the outlet and inlet pipes.
The air-supply is first admitted into the hollow cover e, through orifices arranged in
such a manner as to break the force of any dangerous current of gas; from thence it
passes through the pipe 3, safety-bulb, inlet air-pipe f and nozzle f¹ to the burner a.
The products of combustion escape through the outlet pipe f4, through the bulb
and pipe f into a chamber in the hollow cover e, from whence they escape into the
atmosphere.
The two glass vessels 6 and 61, with the liquid contained in the space between them,
form lenses for magnifying or concentrating the illuminating power of the lamp.
In case the outer glass vessel b' be accidentally broken and the inner glass vessel b
left intact, the lamp will continue to burn, without prospect of immediate danger, and
may be extinguished at leisure; but should the inner glass vessel be broken, the lamp
will be immediately extinguished by the liquid liberated from the space between the
said vessels b and b¹.
Should the lamp be accidentally upset, the liquid normally contained in one of the
safety-bulbs will flow into the bent pipe attached thereto, and close the same, thus
extinguishing the lamp by preventing either the admission of air or the escape of
products of combustion, according to which of the two safely-bulbs is thrown into
action. As previously explained, the bent tube of the one safety-bulb is at right
angles to the bent tube of the other safety-bulb, and, moreover, each bent tube is
parallel with the adjacent side of the cover e, so that no matter on which side the
lamp falls, one of the safety-bulbs becomes operative. In the event the lamp being
plunged into gas at a high pressure, meeting with gas flowing at a high velocity, or
firing, the cork-floats fare brought into play and temporarily stop the air-inlet and
the air-outlet respectively. The cork-floats f" may, however, be dispensed with;
under these circumstances, the flame of the lamp would be extinguished by a current
of gas flowing through the pipe fat a sufficiently high velocity. As an alternative
safety-arrangement, bulbs may be employed fitted with valves floating on mercury. 5
The mercury, on the lamp being overturned, flows from under the valve-floats, the
valves being thereupon closed by the action of the valve-springs with which they are
provided.
For indicating the presence of fire-damp, a nozzle f10 is provided on the inlet
tube just above the lamp-burner. The fire-damp, if any, issues in a jet from the 5
nozzle 10; and although harmlessly burning within the lamp indicates the presence
of danger.

page_text: Although I have described glass vessels b and b¹ of a particular shape, other shapes
are applicable for the purposes of this invention.
Figure 4 represents in sectional elevation the invention illustrated in Figure 1,
with the addition of an incandescent electric light. The general construction remains
the same.
The battery g is contained in the bottom of the lamp. The bulb h is
entirely surrounded by acidulated liquid, on the surface of which the oil-lamp is
caused to float. It will be observed the glass vessels b and 6¹ have in this instance
been slightly modified, their lower ends being formed into necks, the one adapted to
fit within the other. The bulb appertaining to the electric light is placed in the
smaller neck. The terminals of the battery and the wires of the lamp are some
distance apart, and the circuit is maintained by means of acidulated liquid forming a
connection between the said terminals and wires and contained within the neck of the
bulb h; which liquid, in case of fracture of the adjoining parts through accident, runs
out and breaks the circuit, the incandescent wire or filament being immediately
cooled. By these means is afforded a safety-lamp adapted for testing purposes, and
being compact in construction, safe and economical in use, and having great
illuminating power in the directions in which the rays of light are concentrated by
the action of the lenses formed by the two glass vessels 6° and 6¹ and the liquid
contained between them.
Figure 5 represents in sectional elevation a further modification in which means
are provided for automatically breaking the electric circuit in case the lamp falls or is
placed on its side, and for automatically remaking the circuit when the lamp is
restored to its erect position. The plug or stopper k in the neck of the bulb h
is prolonged and caused to project into the interior of the said bulb; a portion of the
projecting part of the plug is cut away to form a space k³, through the centre of which
the current from the battery is caused to pass. The battery-wire k² is divided so as
to leave two ends a sufficient distance apart projecting upwards and downwards
respectively into the space ¹; the bottom of the bulb h is supplied with mercury or
with fine filings of copper or other conductive metal. The mercury or filings serve
to electrically unite the two ends of the divided battery-wire k², but when the lamp
falls on one side, the connecting medium, under the influence of gravity, flows away
from the plug into the lower portion, for the time being, of the bulb h, thereby
breaking the electric circuit and extinguishing the lamp. Upon restoring the lamp
to the upright position, electrical connection is automatically re-established and the
lamp relighted.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I claim :—
1st: The improved construction of safety-lamp, substantially as herein described;
and wherein the illuminating agent is surrounded with water or other liquid for the
purpose of quenching the same in the event of the lamp being broken.
2ndly: The improved construction of lamp adapted for colliery and other purposes,
and provided with a double casing of glass charged with water and arranged in such
a manner as to form plano-convex lenses, substantially as herein described.
3rdly In a safety-lamp, the improved means, substantially as herein described,
for effecting the extinction of the illuminating flame in the event of the lamp being
turned upon its side; such means comprising two passages for the admission of air
and the eduction of products of combustion respectively, together with provisions for
closing one or both passages automatically.
4thly The fire-damp detector f10, arranged and operating substantially as herein
described.
:-
5thly In a safety-lamp, arranging the air-inlet substantially as herein described
in relation to the flame of the lamp, whereby, upon a sudden increase of atmospheric
pressure occuring, a jet of air is projected across the flame with sufficient force to
cause its extinction.
6thly:-The improved means, substantially as herein described, for controlling the
admission of air to the inlet-pipe or the escape of products of combustion from the

page_text: outlet-pipe of a safety-lamp, the same including a bulb, partially filled with liquid,
which, upon the lamp being overturned, acts as or renders operative a sealing device
for closing the passage to which the same is applied.
7thly In a safety-lamp, the combination of two safety-bulbs, of the kind described
in the preceding claiming clause, arranged at right angles to one another and
operating substantially as set forth.
8thly: The improved safety-lamp, arranged substantially as herein described, and
specially adapted for testing purposes; the same comprising an electric lamp for
illuminating and a hydrocarbon burner and detector for indicating the presence of
fire-damp.
9thly In an electric safety-lamp, the improved means for automatically making
and breaking the electric circuit, substantially as described with reference to
Figure 5; and consisting in the employment of mercury, or metal filings or other
suitable substance, for electrically uniting or disuniting the ends of a divided
conductor according to whether the lamp is in a working position or overturned.
Dated this 23rd day of August 1887
G. G. M. HARDINGHAM,
191, Fleet Street, E.C.,
Agent for the Applicant.