IMPROVEMENTS IN LAMPS
Year: 1854

page_text: PROVISIONAL SPECIFICATION left by William Britton Stephens at the
Office of the Commissioners of Patents, with his Petition, on the 21st
April 1854.-A communication.
I, WILLIAM BRITTON STEPHENS, of Mark Lane, in the City of London,
Merchant, do hereby declare the nature of the Invention for "IMPROVEMENTS
IN LAMPS" to be as follows:-
An improved arrangement of an oil bag or flexible reservoir under pressure,
working without friction, and maintaining a constant height or length of the oil-
ascending column (or hydrostatic equilibrium) throughout a stroke of any given
length. This is effected by means of a flexible tube or bag, of the effective
length of half the stroke, attached to two metallic arrangements above and
below, one fixed and the other moveable, in such manner that it folds or doubles
over itself (like a stocking in the act of being drawn on and off) during the
stroke. It is supported on one side by a regularly formed rigid plunger of
sufficient length for this purpose, and on the other by a rigid exterior case with
perforations to drain off any oil which may get to the outside of the bag; and
the plunger is guided by an interior fixed vertical wire or rod, which may also,
if required, moderate the supply of oil, as in the French lamps. This arrange-
ment is most advantageously applied to an oil candle, in which the oil tube
carries a hollow imitation candle above, and at the lower end a plunger of
larger diameter; or the candle itself may form the plunger, or a continuation
of it. The charge of oil is most conveniently introduced into the base of the
candlestick, and thence raised into the flexible reservoir through numerous
small holes covered by a simple flap, by merely drawing up the candle, without
any intervening mechanism.

page_text: In the foregoing arrangement the burner descends as the oil is consumed.
For a fixed burner the arrangement is turned upside down, and the plunger is
actuated by a spring beneath it, and it carries no oil tube. This tube works
oil-tight through the metallic cover of the oil bag, and by pushing it down so
that it depresses the plunger, the oil is drawn into the bag, when the tube is
drawn up again to the proper height, leaving the plunger free. Here the
column of oil shortens from below. as the lamp burns, and the spring is so
adjusted that its decrease in tension is compensated by this circumstance. For
larger lamps with fixed burners a hydro-pneumatic arrangement is used, like
the bird fountain inverted, the oil being raised from below by an excess of
pressure on an oil bag or piston and cylinder, regulated by the admission of air
from behind, the air being excluded,-excepting the small and frequent supplies
which can enter only as the descent of the oil in the burner uncovers the mouth
of a small air pipe rising to a sufficient height, and again descending to the
closed chamber at the back of the piston or oil bag. This air tube may also
be placed entirely below the burner, its mouth being closed by the overflow of
oil from the wick, and opened by the gradual and regulated escape of this oil
from the small vessel which receives it to the base of the lamp.