Improvements in Incandescent Electric Lamps.
Year: 1896

page_text: Date of Application, 6th May, 1896
2000
1002
Improvements in Incandescent Electric Lamps.
SAMUEL PHILLIP EASTICK, Chemical Engineer, 47 Ashford Road Crickle-
wood Middlesex, and EGERTON SAYER Electrical Engineer, 51 Ashford Road
Cricklewood Middlesex, do hereby declare the nature of this invention to be as.
follows:-
As is well known the filaments of all incandescent electric lamps after being in
use for some time are consumed or burnt away owing to the presence of a small
amount of oxygen gas that is left in the bulb; a perfect vacuum in which is.
practically impossible to obtain.
It is also well known that the efficiency of every incandescent electric lamp.
gradually diminishes when in use, a fact which is undoubtedly due to the partial
combustion of the filament itself. The removal of these disadvantages would very
materially prolong the life of the lamp and also allow them to work at their
maximum efficiency throughout that life."
By means of our invention we overcome these disadvantages by the removal
of the combustion supporting oxygen that is left in the partial vacuum of the.
bulb.
In our invention we have in addition to the ordinary lamp filament, one or
more short filaments of carbon or other suitable combustible substances connected
with the two platinum terminals of the lamp filament itself, or the additional
filament may have separate terminals. The removal of the oxygen from the
partial vacuum of such a lamp is accomplished in the following manner. The
terminals to which the additional filament is attached is connected with an electric
current which passes through the short filament, rendering it highly incandescent,.
in which state it immediately burns away, converting the whole of the oxygen into
carbonic acid gas. By this means the whole of the oxygen is destroyed and a
rarefied atmosphere of carbonic acid gas exists in the bulb, in which the illuminating:
lamp filament is absolutely incombustible.
We, SAMUEL PHILLIP EASTICK, of 47, Ashford Road, Chemist, and EGERTON
SAYER, of 51, Ashford Road, Electrical Engineer, both in Cricklewood in the
County of London, 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 :-
Our invention relates to improvements in incandescent electric lamps.
It is well known that the filaments of incandescent electric lamps are gradually-

page_text: consumed or burnt away owing to the presence of a small amount of oxygen gas
that is left in the bulbs in which it is practically impossible to obtain a perfect
vacuum. It is also well known that the efficiency of every incandescent electric
lamp gradually diminishes when in use, a fact which is undoubtedly due to the
partial combustion of the filament itself.
The object of our invention is to overcome these disadvantages and thereby very
materially prolong the life of incandescent lamps and also allow them to work at
their maximum efficiency throughout that life, and to this end we remove or
eliminate the combustion-supporting oxygen that remains in the bulb owing to the
imperfect vacuum.
According to our invention we construct a lamp with one or more short filaments
of carbon (or other substance which when heated will combine with oxygen) in
addition to the ordinary filament. The additional filament or filaments is or are
connected with the two platinum terminals of the lamp filament itself, or it or they
may have separate terminals, or a terminal which may be used in combination with
one of the terminals of the ordinary filament.
In the accompanying drawing which is a sectional elevation of a lamp the
additional filament is indicated by the letter a and is represented as attached to
the terminals b, b of the ordinary filament c.
This filament a must have a lower resistance than the filament c, so that, when
an electric current is passed through it, it will be rendered incandescent and
consumed without the liability of the filament c becoming incandescent. If,
however, the additional filament is connected to terminals independent of those of
the main filament it may be of any desired resistance providing it is capable
of being consumed by the current employed.
In manufacturing a lamp according to our invention the air is exhausted through
the tube d in the usual manner; whilst the lamp is still on the pump the terminals
to which the additional filament is attached are placed in an electric circuit and a
current is passed through the short filament whereby it is rendered highly incan
descent, and immediately burns away thereby converting the oxygen into carbonic
acid gas. By this means the whole of the oxygen is destroyed, and a rarefied
atmosphere of carbonic acid gas exists in the bulb, in which the illuminating lamp
filament is absolutely incombustible.
Experiments have shewn that the life of a lamp manufactured as hereinbefore
described will probably be from 3000 to 4000 hours, and that the efficiency will be
very little, if at all, impaired.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. An incandescent electric lamp provided with a filament or filaments in
addition to the ordinary filament, substantially as, and for the purpose, described.
2. An incandescent electric lamp wherein any oxygen remaining in the bulb
after exhaustion is consumed or eliminated, substantially as described.
3. The manufacture and use of incandescent electric lamps, substantially as
hereinbefore described.
1007
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.