Improvements in Lamps.
Year: 1895

page_text: Date of Application, 25th Apr., 1895-Accepted, 6th July, 1895
Improvements in Lamps.
I, JAMES MADISON USHER, of Medford, in the State of Massachusetts, one
of the United States of America, Merchant, do hereby declare the nature of this
invention and in what mauner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This invention has for its object the production of a novel lamp, particularly
desirable for use as a night lamp.
Lamps for this purpose need not produce a large flame on the contrary a com-
paratively small flame is more desirable, and it is also desirable that the lamp be
capable of burning for a long period of time, without requiring refilling and without
attention.
In lamps as usually constructed at the present time the oil conducted to the
burner by the wick is vaporised by the flame more rapidly and in larger quantities
than can be properly consumed by the natural combination with it of the oxygen
in the air, rendering it necessary to employ a burner of such construction as shall
create an artifical draught of air to supply the latter to the flame in such quantities
as shall effect a perfect combustion of the vapours.
This artificial draught of air, however, necessarily increases the size of the
flame and the rapidity with which the oil is consumed, and in ordinary lamps it is
practically impossible to turn the flame down to a low point and obtain perfect
combustion without causing an objectionable odor.
I have accordingly conducted experiments to devise a lamp which would be
capable of producing a small flame and capable of burning for a long period of
time without refilling.
To meet these requirements it is necessary first, to dispense with the artificial
draught, and when the artificial draught is dispensed with some means must be
provided for taking care of the surplus vapours which cannot be consumed except
by artificial draught.
To accomplish this I have provided what I term a vapourising and condensing
chamber located close to and immediately below the burner, and in which the oil
drawn to the burner is vaporised and stored.
All the vapour necessary to support perfect combustion at the burner is drawn
by the flame from this chamber and all surplus vapour condenses in the chamber
and is returned to the reservoir.
In the preferred construction the vapourising and condensing chamber is formed
by an enlargement of the wick-tube immediately below its upper end constituting
the burner, said enlargement or bulb resting upon the neck of the body or reservoir
and acting to sustain the wick tube within the reservoir.
The drawing represents in vertical section one form of lamp embodying my
invention.
Referring to the drawing, in the particular lamp there shown to illustrate my
invention A is an oil reservoir, more or less ornamental in shape and shown as
provided with a central neck a which constitutes a lateral support for the protecting
globe or shade b.
Resting in the mouth of the neck a is a bulb c, which is shown as constituting a
part and an enlargement of the wick tube c, the upper open end c¹ of which
constitutes the burner, the said tube extending down into the oil contained in the
reservoir.
The bulb c contains or forms a chamber, which I have designated the vapourising

page_text: and condensing chamber, through which in the construction shown is passed the
wick which leads from the reservoir through the wick tube to the burner, the said
wick terminating at a level with the top of the burner or immediately below the
same.
The oil is drawn by capillary attraction to the burner, the wick being at all
times saturated with the oil as in all burners.
To light the lamp, a match is applied at the burner to ignite the oil contained in
the same, as in any lamp, the flame thus produced gradually warming the bulb e
and raising the temperature within the vapourising chamber to such a degree that
the oil, as it is drawn to the chamber by the wick, is there vapourised and stored
within the bulb c, and only such portion of the vapour thus generated and stored
rises to the burner and is consumed thereat as will be perfectly consumed by the
natural combination therewith of the oxygen in the surrounding air.
'
All the surplus gas generated within the vapourising chamber remains therein
and gradually cools and condenses in the bottom of the chamber and falls back to
the reservoir through the wick tube.
By this construction I am enabled to maintain a small flame at the burner, that
is, such a flame as results from the natural union or combination of the oxygen
with such portion of the vapour as would perfectly combine with it, and all surplus
vapour which it has hitherto been necessary to burn, and which, therefore, increased
the size of the flame, is in my improved burner condensed and returned to the
reservoir.
I prefer to embody my invention in a lamp constructed substantially as herein
shown, I having found the same productive of excellent results, although my
invention is not necessarily restricted to the same, for the same may be varied and
still come within the spirit and scope of the invention.
The lamp shown is preferably constructed of glass, the reservoir and supporting
tube a being shown as integral, while the wick tube and bulb are formed
independent of the tube a and simply rest thereon.
I prefer glass for the reason that it is a poorer conductor of heat than metal,
and does not heat the vapourising chamber to such a high degree, and therefore
does not generate so much vapour as would a metallic chamber, the glass chamber
more quickly condensing and causing to be returned the surplus vapours which
cannot be consumed at the burner.
I have herein shown and prefer to employ a globe or shade.b to protect the
flame from side draughts, which would tend to make the flame flicker or become
extinguished, but it should be understood that the globe or shade in my improved
lamp is not provided for the purpose of creating any artificial draught to supply
the flame with additional oxygen, but that the said globe or shade need admit no
air whatever below the burner, its sole function being to shield the flame from
draughts of air and to form a sort of air chamber in which the air is heated
that it may more readily combine with the oil vapours to form perfect and ready
combustion.
In my improved lamp the wick need never be raised above the top of the burner,
and therefore the said wick is not consumed to any appreciable extent, a single
wick lasting for between two and three weeks of continuous burning without
renewal,
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A lamp comprising an oil reservoir having a raised neck portion, a wick tube
provided with an enlarged: bulb portion which rests upon the neck and thereby
sustains the wick tube within the neck and reservoir, said enlarged, bulb portion
forming a closed vapour chamber immediately below the upper end of the wick
and close to the burner, the wick passing through the said vapour chamber to the
burner, as described.

page_text: 2. A lamp comprising an oil reservoir having a raised neck portion, a wick tube
provided with an enlarged bulb portion which rests upon the neck and thereby
sustains the wick tube within the neck and reservoir, said enlarged bulb portion
forming a closed vapour chamber immediately below the upper end of the wick
and close to the burner, the wick passing through the said vapour chamber to the
burner, and an externally surrounding globe or chimney, as described.
3. The construction of lamp, particularly adapted for night use, whereby
artificial draught can be dispensed with and consumption of the surplus vapour
controlled by means of a closed vapour chamber as and for the purpose set forth.
Dated the 25th day of April 1895.
WM. BROOKES & SON,
55 & 56 Chancery Lane, London, Agents for the Applicant.