IMPROVEMENTS IN SAFETY LAMPS
Year: 1868

page_text: LETTERS PATENT to William Hann, of Hetton Colliery, near Fence
Houses, in the County of Durham, Secretary to the Hetton
Coal Company, for the Invention of "IMPROVEMENTS IN SAFETY
LAMPS."
Sealed the 4th August 1868, and dated the 7th February 1868.
PROVISIONAL SPECIFICATION left by the said William Hann at
the Office of the Commissioners of Patents, with his Petition, on
the 7th February 1868.
I, WILLIAM HANN, of Hetton Colliery, near Fence Houses, in the
County of Durham, Secretary to the Hetton Coal Company, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
SAFETY LAMPS," to be as follows:-
This Invention has for its object improvements in safety lamps. For
this purpose I form safety lamps with numerous tubes of small diameter,
or with concentric cylinders with narrow spaces between them to carry
off the products of combustion from the flame of the lamp.
In constructing a Clanny lamp I attach a perforated plate to each end
of a series of tubes or concentric cylinders; the plate at one end carries

page_text: a ring, which can be screwed on to a corresponding ring fixed to the
wire gauze casing of the lamp, and the plate at the opposite end fits
into a perforated shield or cap to protect the upper ends of the tubes or
cylinders from currents of air. The casing of wire gauze is surrounded
by a cylinder of glass, the top of which is fixed to a plate, which by
descending rods is fixed to a ring screwed on to the top of the oil
vessel. The ring at the lower end of the set of tubes or cylinders fits
plate has also small holes formed
The holes are bored at an angle,
impinge against the glass before
to the last-mentioned plate, and this
through it to admit air to the lamp.
so that the incoming currents of air
passing through the wire gauze casing, and the holes are protected from
currents of air by a shield or guard.
In constructing a Stephenson's lamp the tubes or cylinders which are
to carry off the products of combustion from the flame of the lamp are
fitted to the top of the glass chimney which surrounds the flame; both
the glass chimney and the tubes are enclosed within the wire gauze
casing of the lamp. The in current of air enters the lamp through small
perforations in the lower frame, then passes through the gauze and under
the interior glass chimney to the burner. The small perforations above
mentioned are protected from currents of air by a shield or guard.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said William Hann in the Great Seal Patent Office
on the 7th August 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HANN, of Hetton Colliery, near
near Fence Houses, in the County of
Durham, Secretary to the Hetton Coal Company, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria by Her
Letters Patent bearing date the Seventh day of February, in the
year of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did for Eerself, Her heirs and successors,
give and grant unto me, the said William Hann, Her special licence,
that I, the said William Hann, my executors, administrators, and
assigns, or such others as I, the said William Hann, 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

page_text: 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
SAFETY LAMPS," upon the condition (amongst others) that I, the said
William Hann, 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.
NOW KNOW YE, that I, the said William Hann, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say:-
In constructing safety lamps according to this Invention I adapt to
them numerous tubes of small diameter to carry off the products of
combustion from the flame of the lamp. To the upper end of the
series of tubes is applied a shield or cap to guard the upper ends of the
tubes from currents of air, whilst the lower end of the series of tubes
is affixed to the top of the glass or wire gauze casing with which the
flame of the lamp is surrounded.
Figures 1 and 2 show a vertical section and side view of a Stephenson's
lamp so fitted with numerous tubes of small diameter to carry off the
products of combustion from the flame of the lamp.
The tubes I form of very thin metal (copper by preference) so that
the weight of the lamp may not be materially increased. The tubes
at each end are attached to plates T', which in the Drawing are shewn
to be flat discs, but they might be concave on the under side if desired,
so as the better to carry off the products of combustion. The plates
have holes formed in them into which the ends of the tubes are
inserted, and the ends of the tubes are then spread out or turned over,
so as to secure them; or in place of thus attaching the tubes to two
plates, the tubes might be bound together and held between two pieces
of wire gauze at their ends; or they might be otherwise held together.
The disc to which the upper ends of the tubes are attached fits against
an internal flange within the lower end of a cap D which protects
the upper ends of the tubes from currents of air. The disc T' to which
the lower ends of the tubes are attached is formed with a cylindrical

page_text: flange projecting down from its outer edge, and this cylindrical flange
embraces the top of the glass of the lamp which is marked H. The
bottom of the glass (as described in a Provisional Specification lodged
by me and another on the 6th day of August instant) rests upon and
is ground to fit accurately to the upper surface of the ring I, which is
screwed into the lower part I of the frame of the lamp; an elastic but
non-combustible substance might also be interposed betwen the glass
and the rings at top and bottom. The outer circumference of this
ring at a point below the bottom of the glass nips or encloses the wire
gauze casing between itself and the ring I of the lower part of the
frame, as is clearly seen in the enlarged view of this part of the lamp at
Figure 6, thus effectually preventing any current passing between the
gauze and the glass. The in current of air enters the lamp through per-
forations A, A, in the lower frame, then passes through the exterior
gauze under the interior glass chimney H into an annular chamber, and
thence upward through an inner horizontal gauze or perforated plate I
to the burner K. The present arrangements and appliances of this
part of safety lamps are liable to defective fitting, and frequently render
lamps insecure, whilst the above method has been proved tight under
the pressure of extreme velocities of explosive gas. The wire gauze
casing of the lamp which surrounds the glass is marked U, this wire
gauze casing. I continue up, so that it also surrounds the set of tubes T,
and it is turned over so as to cover over the upper ends of these tubes,
as is more clearly seen in the enlarged view of this part of the lamp
shewn at Figure a. The cap or wind guard which the Drawing shows
as applied to the tops of the tubes is the guard which I prefer to
employ, and is made as described in the Provisional Specification before
referred to, but other guards or caps might be used in combination with
the tubes to protect their upper ends from currents of air. The cap or
wind guard shewn in the Drawing is composed of a hemispherical cap,
through which holes or perforations D' are formed, and within the
hemispherical cap is an arched guard E having in its centre an
opening E', or numerous smaller openings might be employed in place
thereof. The lower part of the lamp is also shown to be formed in the
manner described in the Provisional Specification above referred to, but
other ways of forming the bottom of the lamp might be resorted to
when using tubes of small diameter to carry off the products of
combustion as above described.
Figures 3 and 4 show my improvements applied to what is known

page_text: as a Clanny lamp. The top of the lamp is constructed in a similar
manner to that above described; the wire gauze cylinder which sur-
rounds the burner is marked G, it is attached by a screw at its lower
end to the oil vessel of the lamp, and at its other end to a screw ring J
at the lower ends of the tubes T. An exterior wire gauze casing or a
thin metal tube L surrounds the tubes T, as is more clearly seen in the
enlarged view Figure c; the lower end of the tube L is fitted at its
bottom end to the middle plate M of the framework, and at the top to a
projecting inner flange of the cap or guard. In the lamp shewn in the
Drawing the in current of air enters the lamp through perforations in
the lower frame, and passes below an inner shield P, P, to the burner K;
the middle plate of the frame above mentioned has also small holes R, R,
formed, through which air may be admitted to the interior of the
gauze. These holes may be protected by a shield or guard S, S, either
external or internal.
Having thus described the nature of my Invention, and the manner
of performing the same, I would have it understood that what I
claim is,-
First. The application to safety lamps of numerous tubes of small
diameter to carry off the products of combustion from the flame.
Second. Employing a cap or guard in combination with a series of
tubes employed to carry off the products of combustion from a flame
of a safety lamp, so as to protect the tops of such tubes from currents
of air.
Third. Attaching the lower end of a series of tubes to the top of the
wire gauze cylinder or glass chimney with which the flame of the lamp
is surrounded, as herein described.
In witness whereof, I, the said William Hann, have hereunto
set my hand and seal, this Fifth day of August, in the year
of our Lord One thousand eight hundred and sixty-eight.