Improvements in Incandescent Electric Lamps.
Year: 1891

page_text: Date of Application, 3rd Apr., 1891
Complete Specification Left, 2nd Jan., 1892-Accepted, 2nd July, 1892
PROVISIONAL SPECIFICATION.
Improvements in Incandescent Electric Lamps.
We the undersigned ERNEST BOEM of 6 Stonefield Street Cloudesley Street
London Electrical Engineer and ERNEST BAILEY of 103, Judd Street, Euston
Road London do hereby declare the nature of this invention to be as follows:-
The object of this invention is to produce an electric lamp which shall combine
all the advantages of the incandescent lamp with those of the arc lamp.
We effect this in the following manner:
1. The lamp consists of a duplex ring or disc conductor of large sectional area &
low resistance or
2. Of one or more ring conductors coupled up in series or parallel.
The lamp is in the form of a globe with a neck. Through this neck are passed
two platinum wires sealed in the glass. They are connected to two copper wires
which pass through the ring conductor to which they are attached by screws or
other means.
The ring conductor is composed of a circle or disc which is coated with calcium,
whereby all gases which would dim or destroy the clearness of the glass are
prevented & at the same time more illuminating power is given and much greater
durability.
In witness whereunto we the undersigned have hereunto set our hands this
Third day of April One thousand nine hundred and ninety-one.
COMPLETE SPECIFICATION.
Improvements in Incandescent Electric Lamps.
We, ERNEST BOEHм, of 6, Stonefield Street, Islington, and ERNEST BAILEY,
of 103, Judd Street, Bloomsbury, both in the County of Middlesex, Electrical
Engineers, do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
The object of this invention is to produce an electric lamp of the incandescence
type, but possessing greater illuminating power and durability than characterise the
incandescent lamp in common use at the present time, and in which a carbon
filament of small section and fragile nature is employed.
A lamp constructed according to our invention is represented in the accompanying
drawings, whereof
Fig. 1 is a side elevation and
Fig. 2 a horizontal section.
A is a glass bulb, from which the air has been exhausted, and formed with a
neck a, whereby the lamp is mounted in a holder which may be of the usual
description. BB are
two platinum wire conductors, sealed airtight in the
substance of the glass bulb, and extending or connected to a ring C, preferably
flat, of comparatively large sectional area and low resistance. The ring C is
composed of carbon and calcium or calcium oxide, and is mounted on the extremities
of the conductors B3 B', a small piece of carbon being inserted between the ring
and each conductor.
The electric current, in passing from the conductor B to the conductor B¹, or
vice versi, traverses both halves or branches of the ring C and raises the same to a

page_text: state of incandescence. If, owing to disintegration or accident, either half of the
ring becomes fractured, the remaining branch continues to serve as a conductor
and light-emitter.
In the preparation of the illuminating conductor C, we stamp a ring from
cartridge paper, parchment or other suitable vegetable matter, and carbonise the
same. We then coat the carbonised ring with calcium by immersing it in a bath
of liquid hydrocarbon, such as benzoline, charged with calcium oxide and main-
tained in a state of agitation, an electric current being passed through the ring,
whilst so immersed, for the purpose of highly heating the same. On removal from
the bath, the ring will be found to have received a coating of calcium in conjunction
with a certain proportion of carbon, and when dry, is ready for attachment to the
wire conductors of the lamp in the manner hereinbefore described.
Owing to the circumstance that calcium or calcium oxide preponderates in the
composition of the ring when finished, the illuminating power and durability of
the lamp are greatly increased. Moreover, there is little, if any, tendency for the
clearness of the glass to become impaired, owing to the liberation of gases and the
deposit of solid matter on the interior of the bulb.
Although we have alluded to the illuminating conductor as a ring, it will be
obvious that it may assume an elliptical or wavy form, without departing from the
principle of our invention.
Two or more ring conductors of the kind hereinbefore described may be mounted
within the same globe or vacuum chamber and may be coupled up either in series
or 'parallel.'
Having thus particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we claim :-
:-
1. In an electric lamp of the incandescence type, the employment of a stamped
ring or equivalent endless conductor, connected at two points to the wires communi-
cating with the source of supply the two halves or branches of the endless
conductor forming a duplex connection between the said wires, substantially as
herein described.
2. In an electric lamp of the incandescence" type, the employment, as a body to
be raised by the electric current to a state of incandescence, of a ring or equivalent
endless conductor, of comparatively large sectional area and low resistance,
arranged and operating substantially as herein described.
3. The improved electric lamp constructed and operating substantially as herein
described and comprising a stamped ring or equivalent endless conductor, composed
of calcium, or calcium oxide, and carbon, connected at two points with the wires
communicating with the source of supply and enclosed in a globe or bulbous vessel
in an exhausted state.
Dated the 28th day of December 1801
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.