Improvements relating to Pumps for Exhausting Electric Incandescent Lamps.
Year: 1897

page_text: Date of Application, 1st Dec., 1897
Complete Specification Left, 30th Aug., 1898-Accepted, 5th Nov.,
1898
Improvements relating to Pumps for Exhausting Electric
Incandescent Lamps.
I, FREDERICK JAMES SATCHWELL, Electrical Engineer, 55, Lightfoot Road,
Hornsey, Middlesex, do hereby declare the nature of this invention to be as
follows:-
An invention whereby all the oxygen & combustion supporting gas is converted
into a none-combustion supporting gas in a highly rarefied condition in all the
tubes & connections thereto of any pump which obtains any degree of vacuum.
This-I-accomplish-in-the-following manner-Upon-one of the tubes leading to the
pump I connect a vessel to which vessel the objects to be exhausted are also
connected in this vessel I cause an electric are to be formed thus consuming &
converting any oxygen in the tubes & connections thereto of the pump.
Dated this 29th day of November 1897.
Improvements relating to Pumps for Exhausting Electric
Incandescent Lamps.
I, FREDERICK JAMES SATCHWELL, of 55, Lightfoot Road, Hornsey, in the County
of Middlesex, Electrical Engineer, 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:—
My invention relates to means whereby during the process of exhausting the bulb
of an electric glow lamp the oxygen of combustion supporting gas in the bulb and
pump connections is consumed or converted into a highly rarefied gas that will
not support combustion, by which means an improved vacuum is obtained in the
bulb, and the life of the lamp is lengthened.
In carrying out my invention, I proceed as follows, that is to say, in communica-
tion with the passages connecting the exhaust pump and the lamp bulb I provide
a chamber furnished with carbon pencils or rods through which a current of
electricity can be passed and an arc struck, or with, a carbon filament which can
be made incandescent by a current passed through it. The current is sent through
the pencils or filament after a high vacuum has been attained, the remaining
oxygen or combustion supporting gas being thereby partially occluded in the hot
77

page_text: carbon rods or filament, and partially converted into a gas that will not support
combustion. The application of the current is momentary and may be repeated
several times if desired.
In the accompanying drawing I have illustrated more or less diagrammatically
how my invention may be carried into effect.
A is a bulb to be exhausted; B is the passage leading to the exhausting pump;
C is a chamber communicating with said passage and with the lamp bulb.
D, D are carbon rods or pencils resting in contact with each other and carried by
copper or like tubular sockets E, E connected to terminals F, F secured in the
walls of the chamber C. G, G are conductors connecting the terminals to a
suitable source of electricity. One of the rods or pencils D is flexibly supported
so that by a tap or shake it can be momentarily separated from the other rod or
pencil and the arc thereby struck when the current is on.
In some instances I support one of the carbon pencils in a kind of stuffing-box
or flexible joint sealed with mercury whereby it can be withdrawn and held away
from the other rod for the purpose of striking the arc.
The air is exhausted from the bulb in the usual manner, but before the operation
is completed a current of electricity is passed through the pencils or rods D, D
and an arc is struck by momentarily separating the rods, by which means the
attenuated oxygen in the bulb and pump connections is partially occluded in the
hot carbon pencils, and partially converted into a gas that will not support com-
bustion. The arc may be struck two or three times or as often as desired, and then
the bulb is sealed off in the usual manner.
I sometimes effect the same object by means of a carbon filament in the
chamber C rendered incandescent by a current of electricity passed through it.
Having now particularly described and ascertained. the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. In connection with a pump for exhausting electric incandescence lamps,
a chamber communicating with the passage from the lamp to the pump, and
means whereby an arc can be struck or a carbon filament rendered incandescent
in said chamber, for the purposes specified.
2. The method of treating the rarefied air in the bulb of an electric glow lamp
by an electric arc or an incandescent filament, during the process of exhausting
the bulb, substantially as, and for the purposes, specified.
Datal this 90th d..
J
1000
GEORGE HARRISON,
35, Therapia Road, Honor Oak, London, Agent for the Applicant.