IMPROVEMENTS IN RAILWAY CARRIAGE LAMPS
Year: 1878

page_text: LETTERS PATENT to John Pitt Kennedy, of Lupus Street, in the County of
Middlesex, Civil Engineer, John Latham, of Folkestone, in the County of Kent,
Gentleman, and John Andrews Dryden, of Elsley Road, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN RAILWAY CARRIAGE LAMPS."
Sealed the 2nd July 1878, and dated the 19th January 1878.
PROVISIONAL SPECIFICATION left by the said John Pitt Kennedy, John
Latham, and John Andrews Dryden at the Office of the Commissioners of
Patents on the 19th January 1878.
JOHN PITT KENNEDY, of Lupus Street, in the County of Middlesex, Civil Engineer,
JOHN LATHAM, of Folkestone, in the County of Kent, Gentleman, and JOHN
ANDREWS DRYDEN, of Elsley Road, in the County of Surrey. "IMPROVEMENTS IN
RAILWAY CARRIAGE LAMPS."
Our first improvement in railway carriage lamps has for its object to burn colza or
other fixed oils in an eigand lamp, in an effective manner, without the use of a
glass chimney.
The burner itself does not very materially differ in construction from ordinary
argand burners, in which cylindrical or round wicks are employed. The oil is sup-
plied from a reservoir above by two oil tubes which convey it direct to the oil
chamber surrounding the wick.
The burner is placed in an air chamber which is supplied with air from the out-
side through two branch pipes in the usual manner of railway roof lamps, and a
dome or deflector is adapted as a cover to this chamber for the purpose of deflecting
the air on to the outside of the flame.
There is a cylindrical opening through the centre of the burner, as usual, for the
purpose of admitting air to the interior of the wick and the central part of the
flame.
The lamp is enclosed in a glass casing or envelope which is air-tight, or so con-
structed that air to support combustion can only be supplied to the burner through
the air pipes provided for the purpose.

page_text: For a proper combustion of the oil in an argand burner, air must be induced to
pass up the central opening to the interior of the flame, and in ordinary argand
lamps this is effected by means of a glass chimney, the use of which, however, is
objectionable in railway carriage lamps, as they are liable to break, and the lamp
becomes useless for a time. To remedy this defect (and in fact in order to dispense
with the use of a glass chimney) we adapt to the burner a circular plate which fits close
round the burner, but leaves a narrow annular space between its outer edge and the
inside of the dome. This annular space gives ample room for the passage of the air
that is required to impinge on the outside of the flame, but prevents the passage of
an excess of air to this part.
The consequence is that as there is a certain amount of pressure of air in the air
chamber below, and the air being unable to escape, except through the central
opening, is obliged to pass up this passage to the interior of the flame, and
therefore to supply this part with the requisite quantity of oxygen to support
the combustion of the oil, and prevent the formation of smoke.
Our next improvement has for its object to so construct the roof lamp and its
appendages or accessories, that it will act as a ventilator to the compartment to
which it is adapted. To this end the glass dish or envelope in which the lamp
is suspended, is made a fixture in the roof of the compartment, as is also the
concave reflector, and the metal chimney connected therewith.
The glass dish or envelope is mounted in a metal ring, which is permanently
.secured to the roof of the carriage by screws or otherwise, and round this ring
a number of holes are made, so as to allow the vitiated air from the compart-
ment to pass into the space above the concave metal reflector round the metal
chimney. From this space the vitiated air is allowed to escape through suitable
openings into the atmosphere.
A large hole is made in the central part of the glass dish to receive the lamp which
is introduced from below and is suspended from the glass dish, air to support the
combustion of the oil being supplied to the interior of the lamp through openings
or holes made around the fittings whereby the lamp is suspended. This air being
drawn from the compartment instead of from the external air, also consists in
promoting ventilation, and together with the gaseous products of combustion,
pass up the metal chimney into the external atmosphere, and in so doing heat the
chimney and the space surrounding the same.
In order to prevent the lamp from falling, should the glass be broken, it may be
held in a ring suspended from two arms attached to the roof of the carriage.
We have said that a series of holes are made in the metal ring, in which the glass
dish is suspended. These holes will not only act as ventilators, but when the door
of the compartment is open, they will allow air to be drawn from the outside, and
discharged into the compartment instead of the air being allowed to rush down the
chimney into the interior of the dish, and thus put out the light.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Pitt Kennedy, John Latham, and John Andrews Dryden in the
Great Seal Patent Office on the 19th July 1878.
JOHN PITT KENNEDY, of Lupus Street, in the County of Middlesex, Civil Engineer,
JOHN LATHAM, of Folkestone, in the County of Kent, Gentleman, and JOHN
ANDREWS DRYDEN, of Elsley Road, in the County of Surrey. "IMPROVEMENTS IN
RAILWAY CARRIAGE LAMPS."
Our first improvement in railway carriage lamps has for its object to burn colza
or other fixed oils in an argand lamp in an effective manner, without the use of a
glass chimney.
It will be seen on reference to the accompanying Drawings, (in which Fig. 1,
Sheet I., is a vertical section of the lamp,) that the burner itself does not very materially
differ in construction from ordinary argand burners, in which cylindrical or round
wicks are employed.
The oil is supplied from a reservoir a, a, above by two oil tubes a¹, a¹, which con-
vey it direct to the oil chambers 6 surrounding the wick of the burner which is
placed in an air chamber c which is supplied with air from the outside through two
branch pipes c¹, c¹, in the usual manner in this construction of railway roof lamps.
A dome or deflector d is adapted as a cover to this chamber c, for the purpose of
deflecting the air on to the outside of the flame.
.
There is a cylindrical opening b¹ through the centre of the burner, as usual, for
the purpose of admitting air to the interior of the wick and the central part of the
flame.
The lamp is enclosed in a glass casing or envelope e, e, which is air-tight, or so
constructed that air to support combustion can only be supplied to the burner through
the air pipes c', c¹, provided for the purpose.
For a proper combustion of the oil in an argand burner, air must be induced to
pass up the central opening b¹ to the interior of the flame, and in ordinary argand
lamps this is effected by means of a glass chimney, the use of which, however, is
objectionable in railway carriage lamps, as such chimneys are liable to break, and
then the lamp becomes useless for a time. To remedy this defect (and in fact in
order to dispense with the use of a glass chimney), we adapt to the burner a circular
conical plate which fits close round the burner b, but leaves a narrow annular
space 1, 1, between its outer edge and the inside of the dome d, as seen best in the
sectional plan view, Fig. 2. This annular space 1, 1, gives ample room for the passage
of the air that is required to impinge on the outside of the flame, but prevents the
passage of an excess of air to this part.
The consequence is, that as there is a certain amount of pressure of air in the air
chamber c below, and the air being unable to escape, except through the central
openings, is obliged to pass up this passage to the interior of the flame, and there-
fore must supply this part with the requisite quantity of oxygen to support the
combustion of the oil, and prevent the formation of smoke.
Our next improvement has for its object to so construct the roof lamp and its
appendages or accessories, that it will act as a ventilator to the compartment of the
carriage to which it is adapted.
Fig. 3, Sheet II., is a vertical section of a railway roof lamp, constructed according
to our improvements.
The glass dish or envelope e in which the lamp b is suspended, is made a fixture
in the roof of the compartment, as is also the concave reflector g and the metal
chimney h connected therewith.
The glass dish or envelope e is mounted in a metal ring i, which is permanently
secured to the roof of the carriage by screws or otherwise, and round this ring i a
number of holes are made, so as to allow the vitiated air from the compartment
to pass into the space above the concave metal reflector g, and round the metal

page_text: chimney h. From this space the vitiated air is allowed to escape through suitable
openings into the atmosphere, as indicated by the arrows.
A large hole is made in the central part of the glass dish e to receive the
lamp b which is introduced from below, and is suspended from the glass dish e,
air to support the combustion of the oil being supplied to the interior of the
lamp through openings or holes made around the shoulder of the lamp casing
at k, k. The lamp is suspended by means of three pins n, which are screwed
into the lamp casing, and project through the side. Vertical grooves m are made in
the ring (from which the lamp is suspended) for the purpose of allowing the pro-
jecting pins to pass when the lamp is pushed up into the glass e. By turning the
lamp round a trifle, the pins n will be made to rest upon the edge of the ring 7, and
will hold up the lamp. A spring stop may be used to prevent the lamp from turning
round, and dropping out of the glass.
In order to prevent the lamp from falling, should the glass e be broken, it may be
held in a ring suspended from three arms or rods o attached to the roof of the
carriage, or to the stationary reflector g, as shewn in the Drawing. The air to sup-
port combustion being drawn from the compartment, instead of from the external
air also assists in promoting ventilation, and together with the gaseous products of
combustion passes up the metal chimney h into the external atmosphere.
We have said that a series of holes are made in the metal ring i in which the glass
dish is suspended. These holes will not only act as ventilators to the carriage, but
when the door of the compartment is opened, they will allow air to be drawn from
the outside, and discharged into the compartment, as indicated by the dotted arrows
in the Drawing, instead of the air being allowed to rush down the chimney h into
the interior of the dish e, and thus put out the light.
Having now described our Invention of "Improvements in Railway Carriage
Lamps," and having explained the manner of carrying the same into effect, we claini
as the Invention secured to us by Letters Patent, as aforesaid :-
First. The adaptation to argand burners of the conical ring f in combination with
the dome or deflector d for the purpose of controlling the supply of air to the burner
or flame, and causing an adequate supply of air to pass up the central opening b' of
the burner to the middle of the wick or flame, as and for the purpose herein set
forth.
Second. The mode herein set forth and shewn in Sheet II., of constructing railway
carriage roof lamps, so that the use of air pipes, oil pipes, elevated oil reservoirs and
glass chimneys may be dispensed with.
Third. We claim the combination with the reflector g of the perforated ring i,
for the purpose of ventilating the compartment by carrying off the heated or foul
air therefrom, and conducting it into the external atmosphere, as herein set forth.
In witness whereof, I, the said John Pitt Kennedy, have hereunto set my hand
and seal, the Eighteenth day of July, in the year of our Lord One
thousand eight hundred and seventy-eight.
J. PITT KENNEDY. (L.S.)