IMPROVEMENTS IN MINERS' SAFETY LAMPS
Year: 1879

page_text: LETTERS PATENT to Richard Charles Strolley, of the Ebbw Vale Works,
Ebbw Vale, in the County of Monmouth, Engineer, for the Invention of
"IMPROVEMENTS IN MINERS' SAFETY LAMPS."
PROVISIONAL SPECIFICATION left by the said Richard Charles Strelley at
the Office of the Commissioners of Patents on the 14th October 1879.
RICHARD CHARLES STRELLEY, of the Ebbw Vale Works, Ebbw Vale, in the
County of Monmouth, Engineer. " IMPROVEMENTS IN MINERS' SAFETY LAMPS."
Miners' safety lamps as at present constructed are provided with finely perforated
metal for the passage of air or vapour to or from the interior of the lamp for the
maintenance of the flame within the lamp, but such perforated metal becomes often
so highly heated when in use in situations where much fire damp or explosive gas
is present as to convey such heat to and cause the ignition of the gases surrounding
the lamp.
The object of the present Invention is to remedy this evil. For this purpose I
substitute for the perforated metal usually employed a material of a low conducting
power, and of substance that will admit of some extent of surface to the per-
forations for the passage of air or vapour to and from the interior of the lamp so as
to lessen the passage of heat, and thereby prevent the danger of ignition of the
surrounding gases.
The material which I have found to answer well is porcelain, or earthenware,
glazed or otherwise, applied to a suitable part of the lamp; and I form such material
as a disc, say about 2 inches in diameter and of 1½ of an inch in thickness, perforated
with holes of about 1/4 of an inch in diameter, and in number, say, from 50 or 60
to the square inch of surface.
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These details may however be varied.

page_text: The Drawing, Figure 1, represents the section of one form of miners' safety lamp
now in use but with my Invention applied to it. a is the oil vessel, and 6 the wick tube
thereof. This vessel a it will be seen is screwed into the frame c of the lamp at a'. dis
the glass cylinder through which the rays of light pass from the lighted wick from
the wick tube b. This glass tube d is supported on the gallery or drum e, which is
perforated with a series of holes e' to admit air from the exterior by the small
holes to support combustion for the light required. Externally of these holes e¹,
and between them and the holes f, is applied a surface of wire gauze g or other
suitable material to regulate the current through these holes f and e', and prevent
the passage of heat to and cause ignition of surrounding gases when in an explosive
mixture. The gallery or drum e is, as will be seen, screwed at e² to the frame c, by
which close joints may be formed between the upper and lower ground surfaces of
the glass cylinder or tube d and the parts holding it; h is the funnel or chimney
with a sort of hood h¹ to it to prevent the products of combustion from the chimney
passing too freely to the perforated disc A, arranged according to my Invention. Å
plan view and section of one of these perforated discs is shown separately at
Figures 2 and 3. is a metal plate supporting the funnel or chimney h, and
closing the passage between the lower end of the funnel and the cylinder j. The
hood serves to protect the perforated disc A from the two direct accumulations of
soot and other products of combustion in the lamp. i, i, are outlets for the escape
of air passing through the lamp. The arrows indicate the direction of the respective
currents of air. In the use of perforated discs such as I have described, the cylinder
jabove the glass cylinder d is formed of sheet metal in place of wire gauze.

page_text: Having thus described my Invention and means which I adopt in carrying the
same into effect, I would have it understood that although I have shown my
Invention applied to one particular form of miners' safety lamp I do not confine my
improvements to such lamps; but what I claim is the improvements in miners'
safety lamps, whereby material of a low conducting power, and that will admit of
some extent of surface to the perforations formed through it, is employed for the
passage of air or vapour to and from the interior of the lamp so as to lessen the
passage of heat, and thereby prevent the danger of ignition of the surrounding
gases, substantially as stated.
In witness whereof, I, the said Richard Charles Strelley, have hereunto set
my hand and seal, this Seventh day of April, in the year of our Lord One
thousand eight hundred and eighty.
R. CHARLES STRELLEY. (L.S.)