IMPROVEMENTS IN MINERS' SAFETY LAMPS, AND IN THE MODE OF MANUFACTURING THE SAME
Year: 1867

page_text: PROVISIONAL SPECIFICATION left by Frederick Foster at the Office of
the Commissioners of Patents, with his Petition, on the 2nd December
1867.
I, FREDERICK FOSTER, of No. 60, Mortimer Road, Kingsland, in the
County of Middlesex, do hereby declare the nature of my said Invention for
"IMPROVEMENTS IN MINERS' SAFETY LAMPS, AND IN THE MODE OF MANUFACTURING
THE SAME," to be as follows:-
My Invention has for its object the rendering of miners' so called
"safety lamps" really secure and reliable, so that no explosion can take
place through their use in mines or other places where inflammable gases
are present.
My Invention consists,-
I. Firstly, in providing existing lamps or constructing new lamps in such
manner that they carry in, at, or near the roof of the lamp, or in suspending
by a projecting spindle, or piece, or frame above. the flame, an extinguisher,
which extinguisher is carried on a fusible spindle passing through to inside of
extinguisher, and there held by a nut, which may or may not also be fusible;
but if a fusible nut be employed, the use of a fusible spindle is not necessitated.
The spindle and nut, or either or both are made of any known alloy or com-

page_text: position that will fuse or melt should the temperature exceed a certain degree,
and thereby the extinguisher will be instantly set free, and will at once fall
over the flame, and by extinguishing it prevent the possibility of explosion.
I may also provide a guide or guides to ensure the accurate descent of the
extinguisher upon the flame.
II. Secondly, in the peculiar construction and application of three concentric
rings of metal. The first or outer one has a thread upon its lower exterior
surface, by which it can be screwed into a corresponding thread in upper part
of fluid reservoir. This ring has at its upper interior surface a shoulder, by
means of which the second or middle ring is retained in its proper place; this
second ring is provided with perforations or orifices, through which the air
can flow to feed the flame. The second or middle ring has at its upper inner
surface a screw or thread, into which is screwed the third or inner ring, which
ring carries the glass of lamp; this ring is, like the second or middle
one, provided with holes or perforations for the admission of air to the
flame. Between the outer and middle and middle and inner rings are
interposed wire gauzes, so that all air entering the lamp by means of the
holes in the rings must pass through a double set of wire gauzes before it can
reach the flame.
III. Thirdly, in an improved construction of the bottom part of miners'
lamps, or that part below the reservoir containing the fluid to be burned. I
construct this part of a metal ring or annular stand, having perforations or
orifices for the admission of air; this ring is provided with an annular shoulder
for the purpose of receiving two diaphragms of wire gauze which are held in
position one above the other by means of a small spring until the bottom is
screwed securely in its place. All air entering from the perforations or
orifices must pass through the double wire gauze partition formed by the two
diaphragms; these diaphragms are bent or made concave, so that there may
be an air space between them.
IV. Fourthly, in the result produced by the peculiar construction described
in the parts of this Specification marked II. and III., that there is double
gauze in every part of the lamp through which air is admitted to the flame,
excepting the part where the light has to pass through, where the flame is
protected by a glass chimney.
V. Fifthly, in the mode of manufacturing that part of the lamp forming
the reservoir for the fluid to be burned; this, with the exception of the
bottom part or floor of reservoir, I prefer to spin up of sheet metal. The
bottom part I make of sheet iron.

page_text: VI. Sixthly, instead of using a tube for the purpose of raising and lowering
the wick, I cut away the lower portion of the tube in such a manner as to
leave sufficient metal only in which to cut a longitudinal slot for the purpose
of raising and lowering the wick.