IMPROVEMENTS IN LAMPS, ESPECIALLY APPLICABLE TO RAILWAY, SHIPS', AND OTHER EXPOSED LAMPS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Albert Marcius Silber at the Office of
the Commissioners of Patents on the 9th March 1878.
ALBERT MARCIUS SILBER, of No. 49, Whitecross Street, in the City of London.
"IMPROVEMENTS IN LAMPS, ESPECIALLY APPLICABLE TO RAILWAY, SHIPS', AND
OTHER EXPOSED LAMPS."
My Invention relates to that description of railway, ships', and other exposed
lamps, in which the burner is contained in a closed chamber, and has the air
required for combustion supplied to it through tubes communicating at top with
the outer atmosphere, and at bottom with a hood surrounding the burner. In
such lamps of present construction such tubes have been made of uniform or almost
uniform section throughout, and at the upper end the ingress of air has been
impeded by forming the orifice for the inlet of air of a number of small perforn-
tions; the supply of air to the lamp is thus rendered very uncertain, causing a
considerable variation in the size of the flame, according as the lamp is moved
through the air, or as the air moves past the lamp with greater or less velocity.
Now according to my present Invention I convey the air to the burners of such
lamps through tubes or passages, the upper open end of which has a comparatively
large sectional area, while such area is made to gradually diminish as the tube or
passage approaches the burner. By this means the external air drawn into the
mouths of such passages by the rarefaction of the air inside the lamp chamber enters
the tube or passage freely, and with little velocity, the velocity increasing very
gradually as it passes down the narrowing passage, while such increase of velocity
is again counteracted by the expansion of the air in passing through the heated
tubes, and so entering the combustion chamber with a steady flow and almost
imperceptible pressure, which is not affected by gusts of wind, or by variation in
the speed with which the lamp is moved through the air, thereby producing a
constant steady flame, and so showing proper combustion.
Furthermore, instead of making the hood surrounding the flame, and so forming
the combustion chamber, closed more or less entirely at bottom, as has been done
heretofore, I make the said hood open at the bottom, so that any excess of air supply

page_text: may find its way out through such open bottom into the lamp chamber without
affecting the flame of the lamp. By this means also any sediment or dirt that may
pass down with the oil or through the air tubes and enter the combustion chamber,
instead of collecting in the bottom of the same, as heretofore, falls into the bottom
of the lamp chamber, whence it can be readily removed from time to time.
In the before-described arrangement of funnel-shaped air tubes or passages these
may conveniently open into the space above the reflector, which fits practically air-
tight on a projecting rim in the lamp, and the case of the lamp above the reflector
is provided with perforations presenting a large collective area, through which the
outer air enters the space freely.
I also construct such lamps with the funnel-shaped passages before described in
combination with the external oil reservoir described in my previous Patent, No. 3318
of 1870, and with the construction of top described in my previous Patent, No. 3254
of 1871.