IMPROVEMENTS In of MINERS' SAFETY LAMPS
Year: 1868

page_text: "IMPROVEMENTS
LETTERS PATENT to Thomas Heppell, of Pelaw, Main Collieries, in
the County of Durham, for the Invention of
MINERS' SAFETY LAMPS."
IN
Sealed the 15th December 1868, and dated the 19th June 1868.
PROVISIONAL SPECIFICATION left by the said Thomas Heppell at
the Office of the Commissioners of Patents, with his Petition, on
...the 19th June 1868.
THOMAS HEPPELL, of Pélaw Main, Collieries, in the County of
Durham, do hereby declare the nature of the said Invention for
"IMPROVEMENTS-IN MINERS' SAFETY LAMPS." to be as follows:-.
"This Invention relates to an improved arrangement of miners' safety
lamps by which the risk of explosion is diminished, the light from the
flame. of the lamp .being transmitted through suitably arranged glass
surfaces, and thus furnishing a less obscure light than is obtained from
lamps where, the light is transmitted through wire gauze.
Above or
around the oil holder of the lamp I arrange a chamber which is
perforated around the outside, the air entering the chamber through
[Price Gd.]

page_text: these perforations. The top of the chamber serves as a support for the
glass surfaces or cylinders which surround the flame, and the top of
the chamber between the support for the glass and the centre opening
(into which the top part of the oil holder screws) is perforated so as to
allow the air to pass out of the chamber to supply the flame of the lamp.
The chamber of the lamp around the flame may be formed by means of
one or more glass surfaces, but 1 prefer to surround the flame by two
concentric glass cylinders, the glass surfaces being so arranged that
should injury arise to the inner cylinder or surface of glass by contact
with the flame or otherwise, the outer cylinder or surface will remain to
protect the flame, while the portions of the inner cylinder of broken will
in most cases fall upon the wick and extinguish the flame. Should
injury arise to the outer cylinder or surface of glass from an accidental
blow or otherwise the inner cylinder will remain to protect the flame.
Above the flame the products of combustion pass away through a
chimney the top of which may be perforated, or the opening may be
protected by wire gauze. Within the chimney is an inner chimney or
contractor, so that should the lamp be exposed to an explosive mixture
of air it will check the escape of the products of a too rapid combustion,
and so extinguish the flame.
The lamp is provided with an outer frame for connecting and
supporting the parts enumerated, and a cap provided witli a ring or
handle is mounted upon such frame over the chimney of the lamp to
divert and disperse the heated air arising from it.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Thomas Heppell in the Great Seal Patent Office
on the Sth December 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
HEPPELL, of Pelaw Main Collieries, in the County of Durham, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of June, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas Heppell, Her special licence that I,

page_text: the said Thomas Heppell, my executors, administrators, and assigns, or
such others as I, the said Thomas Heppell, my executors, administrators,,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN MINERS' SAFETY
LAMPS," upon the condition (amongst others) that I, the said Thomas
Heppell, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
same is
NOW KNOW YE, that I, the said Thomas Heppell, do hereby declare
the nature of my said Invention, and in what manner the
to be performed, to be particularly described and ascertained in and
by the following statement:-
The object of the above-mentioned improvements is to diminish the
risk of mine explosions from safety lamps and yet to furnish a less
obscure light than is obtained by the use of ordinary safety lamps.
My said improvements are of the nature and character following, that
is to say
I use an arrangement of miner's safety lamp embodying the following
improvements in which the light from the flame of the lamp is trans-
mitted through glass, thus furnishing a less obscure light than is
obtained from lamps where the light is transmitted through wire gauze.
Above the oil holder of the lamp I arrange a chamber perforated all
round the outside to the required height, through these perforations the
air enters the chamber, the top of which chamber is supports cylinders or,
chambers of glass between this support and the centre opening (on to
which the top part of the oil holder screws), are perforations where the
air passes out of the chamber to supply the flame of the lamp. The
chamber of the lamp around the flame may be formed by means of one
or more glass surfaces, but I prefer to surround the flame by two
concentric glass cylinders, the glass surfaces being so arranged that'
should injury arise to the inner cylinder or surface of glass by

page_text: contact with the flame or otherwise, the outer cylinder or surface will
remain to protect the flame, while the portions of the inner cylinder if
broken will in most cases fall upon the wick and extinguish the flame.
If the outer cylinder or surface of glass should sustain any injury from
an accidental blow or otherwise the inner cylinder will remain to protect
the flame. Above the flame the products of combustion pass away
through a chimney the top of which may be perforated, or the opening
protected by wire gauze. Within this chimney is an inner conical
chimney or contractor made of wire gauze, so that should the lamp be
exposed to an explosive mixture of air it will check the escape of the
products of a too rapid combustion, and so extinguish the flame. The
lamp is provided with an outer frame for connecting and supporting
the parts above described, and a cap provided with a ring or handle is
mounted upon such frame over the chimney of the lamp to divert and
'disperse the heated air arising from it.
Having thus described the nature and character of the said Inven-
tion, I will now proceed to describe in what manner the same is to be
performed or carried out in practice, which I shall do by referring to the

page_text: details of construction herein-before described, except when used for the
purposes and in the manner herein-before described.
In witness whereof, I, the said Thomas Heppell, have hereunto
set my hand and seal, this Fifteenth day of December. in the
year of our Lord One thousand eight hundred and sixty-
eight.
Witness,
MICHAEL HARLE,
Ouston Colliery,
Fence Houses,
Durham.
THOMAS HEPPELL. (L.S.)