A Miner's Safety Lamp.
Year: 1892

page_text: A Miner's Safety Lamp.
I, WILLIAM EDDINGTON FIELD of Hawthorn in the Colony of Victoria,
Australia, Analyst, 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 has been devised to provide an improved lamp for the use of
miners in mines where there may be dangerous gases or vapours and is arranged
in such a manner as to prevent the possibility of explosions occurring if the lamp be
At the same
lowered or used in places where combustible gases or vapours exist.
time it is so constructed that its working is not affected by draughts or wind.
The lamp is preferably constructed in a shape somewhat resembling an ordinary
swing hand lamp, but the interior consists principally of a chamber enclosing the
flame of the wick the sides of which said chamber are impermeable to gases, whilst
the top and bottom of the chamber are wholly or partially constructed of wire
gauzes, through which the incoming and outgoing gases and vapours must pass.
This chamber terminates at its top in the form of a pipe for the purpose of
ensuring an updraught from the flame. This pipe or tube is covered cowl-wise by
a ventilator cap or shutter. This latter is arranged in such a manner as to enable
the operator to adjust it and in the case illustrated to raise it or lower it at his
discretion, and is also provided with a diagonal slot working on a pin, fixed in the
aforesaid pipe chimney. The cap lifts up and down quite freely and when desired
can be closed right on to the top of the pipe and thus cause the flame to go out
through lack of oxygen. The handle of the lamp is made preferably in the form
of a yoke and consists of a hollow tube near the top of which holes are suitably
arranged for the inlet of air to support the combustion in the lamp. This air pro-
ceeding down to the bottom of the aforesaid tube handle enters into a chamber to
be hereinafter explained, where a false bottom of wire gauze is provided. Immediately
above this false bottom a circular horizontal shutter is placed, the said shutter
being actuated by a spring and kept in an open position by a piece of combustible
material, such as string, or easily melted wire; and from this chamber two upright
tubes ascend and terminate under a wire gauze cap. This latter surrounds the
wick. The wick is arranged in the ordinary manner, is adjustable by the usual
thumb screw and depends into a chamber of oil which takes up all the unoccupied
portion of the bottom of the lamp. An inner glass chimney is preferably provided
for surrounding the wick and consists of a simple glass cylinder, but its use is not
arbitrary. The upper portion of the lamp, under the cap piece, is made in the
shape of a dome and contains an inner lining of non-combustible material, such as
asbestos, between it and the inner plate..
I would now direct attention to the drawings herewith, in which-
Figure 1 is an elevation of my lamp, half being in section.
Figure 2 is a cross section on line 1-2 of Fig. 1 whilst
Figures 3 and 4 are plan views respectively of the circular horizontal shutter in
its closed and open positions.
In these drawings "A" is the yoke shaped pipe handle provided with holes "A1"
for the ingress of air and terminating at the bottom in a circular chamber "B." In
this chamber "B" stands the lamp, at the bottom of which is a wire gauze "B"
in the form of a circular plate and above which is placed a circular horizontal
shutter "C," (Figs. 1, 3 and 4). This shutter is composed as follows.
Attached to a central pivot "C" is a spring "C" the end of which is fastened at
"C" to a circular shutter C' having a segmental opening "C" cut in same and

page_text: small lug "C" provided with an eyelet hole. To this eyelet hole a piece of com-
bustible string or fusible wire "C" proceeds to and is fastened on a rigid eyelet "C","
the whole being so arranged that if the string "C" be at any time burnt by
contact with flame the tension of the coaipressed spring will rotate the shutter round
to the closed position as shewn on Fig. 4 and thus cut off the supply of air vapour
or gas to the flame above.
Over the top of the casing carrying the said shutter are arranged two inlet
Pipes Dfor conveying the air to the wick at the point of combustion, but before the
air reaches the wick it is made to pass through a gauze screen "E." This screen
is circular in shape and surrounds the base of the wick and flame "F."
FI" is an
ordinary ratchet actuated by the thumb and finger for adjusting the height of the
wick. "G" is an internal glass chimney, cylindrical in form and kept in position by
springs attached to the brass rim "G" "H" is the glass chamber enclosing the light
and terminating at its top in a dome "H'," made of copper or other suitable metal,
and provided with an asbestos inner jacket "H" and diaphragm plate "H³." In the
interior of this dome is another wire gauze partition "H" and at the top of the dome
a covering cap "J"is provided. This cap contains a set of ventilator holes "J" and
is made to fit neatly around the top portion or chimney of the dome "H¹." The
cap "J" may be also provided with a diagonal slot "J" said slot being set with a pin
and a small subsidiary slot for fixing the position of the cap when the lamp is at work.
It will be seen that the cap "J" can be lowered at the will of the operator to rest
upon the top of the dome chimney "H" and thus prevent any egress of gases from
the interior of the lamp. I do not confine myself to the particular form of this cap
my object being to control the upward-draught by means of an adjustable shutter."
The tubular handle "A can be removed from the lamp by unclasping the
latch K." This latch "K" may be of any approved design and is only necessary
on one of the legs of the yoke, as both legs of the yoke are kept in position by the
inner vertical tubes "A" (see Fig. 1). A screwed ring "L" is secured to the main
glass "H" which engages with a thread forming a portion of the oil reservoir of
the lamp.
65
The method of working my invention is as follows.—
cr
The latch "K" is unfastened the yoke "A" is then drawn up through
eyelets "A" The body of the lamp can then be unscrewed at "L" and removed,
the small inner glass cylinder "G" lifted up and the wick Flighted and adjusted to
the necessary height by the ratchet "F" The cylinder "G" is then replaced, as
shewn, and the body of the lamp again screwed into position at "L" (care
having been first. exercised in seeing that the cap piece "J" is in its "open" position)
this latter is done by slightly lifting and turning the cap in such a manner that the
pin in the slot "j" is brought down to the subsidiary set slot at "J;" the
yoke "A" is then replaced over the inner tubes "A" and the latch "K" locked in
position and the lamp is ready for use. It is presumed that the circular shutter is
in its open position (as in Fig. 3). The air necessary for the combustion of the
lamp enters at the air holes "A" and descends both legs of the yoke "A" and
enters the bottom chamber "B," whence it proceeds through the wire gauze "B,"
thence through the open shutter "C" into the upright passages "D" and after
passing through the other wire gauze "E" arrives at, and supports the combustion
f, the flame at "F." The up draught, carrying with it the unused and spent
gases and vapours thence proceeds upwards through the cylinder "G" towards,
and through, the conical shaped wire gauze cap "H" whence it is directed by the
diaphragm or inner plate "H" to the ventilated cap or shutter "J" where it may
escape to the outer air. We will presume for example that the lamp has been
lowered into a place containing a mixture of inflammable gases or vapours. In this
case the in-draught of the lamp will cause such inflammable gases or vapours to
proceed down the yoke "A" (in similar manner as hereinbefore described for the air
for combustion), but on the said inflammable gas or vapour passing through "E" it
catches fire at that position, and produces a number of minute explosions which are
reverberated on the plate or diaphragm "H" (see Fig. 1), should however 'the
*r

page_text: gauze plate "E" be damaged, or from some cause work ineffectually and allow the
flame to pass down the tube "D" as far as the circular shutter, the combustible
string or fusible wire "C" (see Fig. 3) will be severed by the heat when the
shutter, by reason of its automatic action, as hereinbefore described will close into
the position shewn on Fig. 4, thus cutting off the incoming supply of gaseous
vapours and preventing the communication of fire from the lamp to the body, of
gas that may be contained in the legs of the yoke "A" or in the mine.
The jacket of asbestos "H2" is for the purpose of keeping the outer surface of
the dome from becoming too hot and thus inconveniencing the person carrying the
lamp and at the same time allowing the inner plate of the dome to keep hot and
thus assist the draught through the lamp. The holes "A1" in the yoke are
arranged in such a manner as to catch a draught of air no matter from what
direction it may be coming in, and it will also be seen that the ventilation in the
cap or shutter piece "J," by reason of the apertures "J" may be made equally
efficacious in a draught or wind coming from any direction. The supply of oil to
the lamp can be inserted at any convenient spot in the ordinary manner.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is.
1. In a miner's safety lamp, a chamber enclosing the flame the sides of which
are impermeable to gases and vapours and the top and bottom of which are wholly
or partially constructed of wire gauzes through which said gauzes the incoming
and outgoing gases and vapours must pass, substantially as hereinbefore described.
2. In a miner's safety lamp, the combination of a lamp with a wire gauze at
the bottom as "E" on the upper surface of which gauze gases or vapours may be
burnt, substantially as and for the purposes set forth.
as
3. In a miner's safety lamp, the combination of an enclosed chamber
"H"
with a tube as "H3" at the top for the purpose of ensuring an updraught for the
flame and products of combustion in the said lamp, substantially as described and
illustrated.
6:
4. In a miner's safety lamp, the combination of a wire gauze division, preferably
shaped as "H4," with an upright tube as H3," the whole being mounted on a
chamber in which combustion takes place, substantially as and for the purpose set
forth.
5. In a miner's safety lamp, an automatic cut off shutter as "C" actuated by a
spring and put into operation by the severing of a combustible string or fusible rod,
substantially as and for the purpose hereinbefore referred to.
6. In a miner's safety lamp, an adjustable cap or shutter as "J" arranged in
such a manner as to cut off altogether, or regulate, the exit of the spent gases,
vapours and unused air, substantially as and for the purposes described and as
illustrated.
7. In a miner's safety lamp, a lead away diaphragm as "H" for the purpose of
concentrating and reverberating the vibrations of minute explosions caused by the
burning of an undesirable gas or vapour in a lamp, substantially as illustrated.
8. In a miner's safety lamp, a jacket of asbestos or analogous material as "H"
arranged in the manner and for the purposes herein before set forth and as illus-
trated.
9. In a miner's safety lamp, the general mechanical construction, combination
and arrangement of all the parts constituting an improved miner's safety lamp as
illustrated on Figs. 1, 2, 3, and 4 of the accompanying drawings.
Dated this 19th day of July 1892.
John P. O'Donnell,
W. E. FIELD.
2, Great George Street, London, S. W., Agent for the said Applicant.