IMPROVEMENTS IN LAMPS FOR BURNING PARAFFIN, PETROLEUM, BELMONTINE, AND OTHER HYDROCARBON OILS WITHOUT THE USE OF GLASS CHIMNEY
Year: 1866

page_text: LETTERS PATENT to Thomas Rowatt the younger, of the Firm of Thomas
Rowatt and Son, of Edinburgh and London, Lamp Manufacturers, for
the Invention of "IMPROVEMENTS IN LAMPS FOR BURNING PARAFFIN,
PETROLEUM, BELMONTINE, AND OTHER HYDROCARBON OILS WITHOUT THE USE OF
GLASS CHIMNEY."
Sealed the 20th July 1866, and dated the 22nd January 1866.
PROVISIONAL SPECIFICATION left by the said Thomas Rowatt the
younger at the Office of the Commissioners of Patents, with his Petition,
on the 22nd January 1866.
I, THOMAS ROWATT the younger, of the Firm of Thomas Rowatt and Son,
of Edinburgh and London, Lamp Manufacturers, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN LAMPS FOR BURNING
PARAFFIN, PETROLEUM, BELMONTINE, AND OTHER HYDROCARBON OILS WITHOUT THE
USE OF A GLASS CHIMNEY," to be as follows:-
In lamps bitherto made for burning these oils the current of air necessary
for the perfect combustion of the gases evolved in the burning of the oils
is obtained by placing a glass tube or chimney above and around the flame.
By my improvements I obtain the necessary current of air by carrying down
a tube of metal or any suitable material from the dome to within a short

page_text: distance of the bottom of the burner, extending its lower rim laterally, so
that the opening remaining between the edge of this rim and the lower body
of the burner becomes an air channel with a much greater superficial area
than the area of the bottom neck of the tube, consequently the tube becomes
an air sluice when the lamp is lighted, and I thus obtain a current of air
which is impinged on the flame in the usual way. But for the perfect com-
bustion of the aforesaid gases I find that a current of air is required to be
also impinged on the flame from outside the dome used in these burners.
I obtain this current by placing another dome over the usual dome, and
perforating its sides so that a current of air rushes up, between the two domes,
and is impinged on the flame from outside the inner dome. I thus obtain a
clear steady light without the aid of any glass chimney or tube whatever above
the flame. Where requisite the flame can be protected from any draughts
or currents of air by a glass shade of any suitable shape fixed to the burner
in any suitable manner, as the flame of a gas lamp is protected from draughts
by the gas shades common in use.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Rowatt the younger in the Great Seal Patent Office
on the 20th July 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
ROWATT the younger, of the Firm of Thomas Rowatt and Son, of Edinburgh
and London, Lamp Manufacturers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of January, in the year of our
Lord One thousand eight hundred and sixty-six; in the twenty-ninth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Thomas Rowatt the younger, Her special licence that I, the said
Thomas Rowatt the younger, my executors, administrators, and assigns, or
such others as I, the said Thomas Rowatt the younger, my executors, adminis-
trators, 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 LAMPS FOR BURNING PARAFFIN,
PETROLEUM, BELMONTINE, AND OTHER HYDROCARBON OILS WITHOUT THE USE OF A
GLASS CHIMNEY," upon the condition (amongst others) that I, the said Thomas

page_text: Rowatt the younger, 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 Thomas Rowatt the younger, do hereby
declare the nature of my 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, reference being had to the figures and letters on
the accompanying Sheet of Drawings (that is to say):-
In most lamps hitherto made for burning bydrocarbon or other oils'
complete combustion is effected by the aid of tall glass chimneys, which have
not only the disadvantage of being easily and frequently broken, but tend to
diminish the amount of light which ought to be produced from a given
quantity of oil by causing too strong a draught of air. The object of my
Invention is to enable currents of air to be directed immediately upon the
flame sufficient to effect perfect combustion, but at the same time not
so strong as to injuriously affect the real light-producing power of the oil
consumed.
My improvements consist in applying to each burner two round-topped'
hollow cones or domes, one exterior and the other interior, both being so
arranged as to produce two separate and distinct currents of air. The form
of the domes resembles that of the ordinary dome, but the openings for the
flame to pass through extend entirely across the tops of the domes and are
expanded or enlarged at their ends, the exterior opening being proportionately
larger than the interior opening as the exterior dome is larger than the
interior. The domes are so connected together as to allow two distinct currents
of air to pass to the flane, and the interior dome rests on supports forming
part of the disc or frame, from the centre of which the wick tube rises, and the
perforations or openings in or between the supports are sufficiently large to
admit of an ample supply of air passing upwards to the flame through the
interior dome. Round the interior dome I make a number of perforations to
admit a second current of air to pass upwards between the domes and act on
the flame, and the effect of these outer and inner currents of air is to cause
the perfect combustion required. If desired, a gallery may be added to
support a globe, which will not only improve the appearance of the lamp but
also conduce to the steadiness of the flame by shielding it from sudden
draughts.

page_text: In the accompanying Sheet of Drawings illustrating my Invention, Fig. 1
is an elevation of a lamp with my improved burner attached; and also having
a globe for shielding the flame from draughts; Fig. 2, an elevation with part
in section of the burner, without the exterior, dome; Fig. 3, a bottom view of
the burner; Fig. 4 a side view, and Fig. 5 a top view of the exterior dome
detached.
b
. a represents the oil chamber; b, the bottom of the burner; and c, the
wick tube. On the part b rests the interior dome d, and in the part 6 there
are apertures e for supplying air to the flame through the inside of the interior
dome d surrounding the wick tube c. On the interior dome a flange is
formed, on which rests the exterior dome f, and in the said flange apertures g
are formed for supplying air to the flame through and between the two
domes. The enlarged openings for the flame at the tops of the domes are
shewn at h, Figs. 1, 2, 4, and 5.
Having now described the nature and particulars of iny said Invention, and
the manner in which the same is to be performed, I desire it to be understood
that I claim the combination of the two domes d and f in. one lamp burner
arranged and constructed as shewn and described, for producing and
directing upon the flame two separate currents of air for the purpose of
effecting complete combustion of hydrocarbon oils without the aid of a glass
chimney.
In witness whereof, I, the said Thomas Rowatt the younger, have here-
unto set my hand and seal, this Twentieth day of July, in the year
of our Lord One thousand eight hundred and sixty-six.
THO. ROWATT, JR. (L.S.)