IMPROVEMENTS IN THE CONSTRUCTION OF GAS LAMPS OR LANTERNS."
Year: 1879

page_text: LETTERS PATENT to William Thomas Sugg, of Vincent Street, in the City of
Westminster, Gas Engineer, for the Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF GAS LAMPS OR LANTERNS."
PROVISIONAL SPECIFICATION left by the said William Thomas Sugg at the
Office of the Commissioners of Patents on the 24th December 1879.
WILLIAM THOMAS SUGG, of Vincent Street, in the City of Westminster, Gas
Engineer. "IMPROVEMENTS IN THE CONSTRUCTION OF GAS LAMPS OR LANTERNS."
This Invention relates to a novel construction of lamp or lantern for use in
streets or other exposed situations, and with either flat flame or argand burners,
and in which the air to support combustion is drawn in through the roof or upper
portion of the lantern.
In carrying out my Invention I prefer to use a dish shaped lantern, which I
secure by its base in any convenient manner to the pillar, or suspend from its upper
part by tubular rods.
This lantern I cover with a slanting metal roof having a large circular opening
in the centre. In this opening I suspend, by stays or other means, a metal chimney
of less diameter than the opening, thus leaving an annular space all round the
chimney through which the air can enter the lantern. Either to the bottom of this
chimney or to the sides of the lantern (or both) I secure a reflector (either of metal,
glass, or porcelain) which extends nearly to the sides of the lantern. The upper
side of this reflector and the lower side of the roof of the lantern will form an
annular passage which serves to conduct the air required for combustion and
ventilation to the interior of the lantern.
In the mouth of the chimney I suspend, in any convenient manner, a conical
porcelain or enamelled metal tube or shade, which will not only serve as an
additional reflector, but will collect the gases of combustion and direct them up the
centre of the chimney, thus inducing a current of fresh air into the lamp and
preventing the reflector from becoming overheated.
A hood is provided to cover the annular opening and prevent the entrance of
rain, snow, or sleet, and the chimney is provided at top with a hood supporting a
baffle plate to prevent the entrance of down draughts.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Thomas Sugg in the Great Seal Patent Office on the 24th
Jane 1880.
.
WILLIAM THOMAS SUGG, of Vincent Street, in the City of Westminster, Gas
Engineer. "IMPROVEMENTS IN THE CONSTRUCTION OF GAS LAMPS OR LANTERNS."
This Invention relates to a novel construction of lamp or lantern for use in
streets or other exposed situations in combination with flat flame burners, to which
the air for supporting combustion is admitted through the roof or upper portion of
the lantern.
In carrying out my Invention I use a bowl or a funnel shaped lantern which I 1
secure at its base in any convenient manner to the pillar, or I may suspend the
lantern by its upper part from tubular pendent rods.
In Sheet I. of the accompanying Drawings, Fig. 1 shews in vertical section a
globular shaped lamp with my improvements applied thereto. A is the framed
glass case supported on a pillar, and through its centre rises a gas supply pipe as
usual, and fitted to this pipe is a flat flame burner B. C is the cover of the lamp
or lantern formed of metal, and having at its centre a tube O' which is slightly
conical, and constitutes virtually an extension of the concentric internal porcelain
chimney D. C² is a conical partition forming part of the metal cover of the lamp,
and rivetted to this partition are clips c which serve to carry a conical reflector E,
made either of opaque glass or porcelain. The upper part of this reflector E serves
as a support for the chimney D which drops over a neck formed on the reflector.
The conical partition C* stands in such relation to the reflector as to form therewith
an annular passage for the descent of the air admitted to the lamp. Immediately
above this partition is a ring of openings c' in the cover of the lamp for admitting
air thereto for supporting combustion after the manner of the lamp for which
obtained a Certificate of Registration under the Designs Copyright Act of 1843, dated
January Twenty seventh, One thousand eight hundred and seventy nine, No. 6134.
The tube C¹ is closed at top by a cap piece Č³ provided with annular openings C³ on
its periphery for the escape of the gases of combustion, and pendent from the cap piece
is a central conical baffler C which deflects the gases of combustion as they ascend
from the chimney to the openings in the cap piece. At the same time this baffler C
prevents a down draught, while it leaves a passage above it for any gusts of air to pass
directly through the cap piece. Supposing the burner to be lighted the heat generated
in the lamp will cause air to be drawn in by the opening c¹ to maintain combustion.
The air on entering the lamp will pass over the edge of the partition C³ and down
the annular passage formed by that partition and the reflector E, which latter will
deflect the air onto the sides of the lamp and cause it to move in the direction of
the arrows to the burner. As, however, the burner is situate near the reflector it
will impart an abundance of heat thereto, which heat however will be rapidly
absorbed by the incoming air. The air will thus be caused to reach the burner in
a rarefied state, and thereby the quality of the light will be improved owing to the
more perfect combustion of the illuminating gas. This deflection of the air onto the
sides of the lamp will ensure a perfect ventilation of the same, all the currents
tending towards the centre, and then ascending and finding their exit by the
chimney. The lamp shewn at Fig. 1 represents one pattern of what I have called
the "City of London Lamp," a second pattern of this form of lamp is illustrated in
sectional elevation at Fig. 2, Sheet II., of the Drawings. In this example the
reflector E is carried by a pendent cylindrical projection of the cover C, but the
annular passage for admitting the air and rarefying it during its progress into the
lamp is retained. The chimney D has a glass or porcelain conical extension D'
(supported from the cylindrical projection of the cover C by clips c) which serves
to collect the ascending gases of combustion and lead them upwards towards the
d

page_text: exit apertures in the cap piece C³. In some cases I propose to raise the conical
extension of the chimney to a level with the top edge of the reflector E, as shewn
by the dotted lines in the Figure. This will prevent the casting of a shadow from
the conical extension onto the reflector and thus widen the area of distribution of
reflected light. In order to ensure a bright economical light in these lamps it is
important to proportion their cubical contents and the areas for the admission of
air and for the escape of the gases of combustion according to the illuminating
capacity of the burner. After careful experiments I have found good results to be
obtained in the "City of London" lamp, by giving to such lamp when fitted with
a burner of a 50-candle power the cubical contents of 6327 cubic inches for the
admission of air an area of 24 square inches, and for the escape of the gases of
combustion an area of 14.12 square inches. Again, for a lamp fitted with a burner
of a 100-candle power, the proportions I employ are,—
Cubical contents of lamp
Area of air admission
Area of escape for gases of combustion
-
-
12,010 cubic inches.
39-3 square inches.
25.5 square inches.
The plane of measurement of the admission and exit areas are taken at the
dotted lines 1, 1, and 2, 2, of the Figures.
Fig. 3, Sheet I., shews in vertical section a street lamp which I designate the
"Westminster" lamp with my Invention applied thereto. As the reference letters
already used are placed on corresponding parts of this Figure it will only be
necessary to remark that this lamp has a six or eight sided closed case A. which is
suspended from pendent rods, that the chimney has the conical extension piece D'
of Fig. 2, and that the lamp is provided with the deep annular passage for rarefying
the air, shewn at Fig. 1. When it is desired to avoid the casting of a shadow from
the conical extension piece D¹ onto the reflector E, the reflector may be flattened,
as indicated by the dotted lines, the upper edge of the reflector being brought to a
level with the lower edge of the extension piece D'. Fig. 4 shews in vertical
section a second form of the "Westminster" street lamp, which differs from Fig. 3
only in that the annular passage formed by the deflector and the cover is short in
Fig. 4 as in Fig. 2.
In constructing the "Westminster" form of lamp I have found a good result may
be obtained in a lamp fitted with a composite burner of 200-candle pover by giving
to it a cubical content of 18,600 cubic inches, and making the area of air
admission 100-5 square inches, and the area for the escape of the gases of combustion
20 square inches.
Having now set forth the nature of my Invention of "Improvements in the
Construction of Gas Lamps or Lanterns," and explained the manner of carrying the
same into effect, I wish it to be understood that under the above in part recited
Letters Patent 1 claim,—
The application to gas lamps or lanterns which are supplied with air from above
for supporting combustion and ventilating the lamp of the means above described
for rarefying the air on its admission to the lamp, and deflecting it onto the sides
of the lamp, as and for the purpose above set forth.
In witness whereof, I, the said William Thomas Sugg, have hereunto set
my hand and seal, the Seventeenth day of June, in the year of our Lord
One thousand eight hundred and eighty.