Improvements in connection with Carbon Electrodes.
Year: 1893

page_text: Date of Application, 13th Jan., 1893
Complete Specification Left, 25th Oct., 1893-Accepted, 25th Nov., 1893
PROVISIONAL SPECIFICATION.
Improvements in connection with Carbon Electrodes.
HARRY THEODORE BARNETT M.I.E.E. 14 Narcissus Road London N.W. do
hereby declare the nature of this invention to be as follows:-
This invention relates to that class of electrode which consists of a number of
fine carbon projections situated upon & outstanding from a carbonaceous or metallic
conducting support.
.
I find that the said fine carbon projections are liable to damage in packing, in
transit when the electrodes are in use & also at other times.
To obviate this difficulty I construct the electrodes with guarding portions attached
to or formed of the substance of the said conducting support they being so disposed
upon & so far outstanding from the same as to prevent the fine projections being
damaged under any of the ordinary conditions which they might be subjected to.
I prefer to arrange that the said guarding portions be of some insulating substance
or (in the case of their being of the same material as the conducting support or of
other conducting material) that they be provided with an insulating face, the said
insulation serving to prevent accidental electric contact when the said electrodes
are in use.
Dated this Twelfth day of January 1893.
HARRY THEODORE BARNETT.
COMPLETÉ SPECIFICATION.
Improvements in connection with Carbon Electrodes.
I, HARRY THEODORE BARNETT Mem. Inst. Elec. Engrs. 14 Narcissus Road
W. Hampstead London N.W. 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 that class of electrode which consists of a number of fine
carbon projections situated upon and outstanding from a carbonaceous or metallic
conducting support.
I find that the said fine carbon projections are liable to damage in packing, in
transit, when the electrodes are in use and also at other times.
When the fine projections are so filamentary as to consist of single fibres of
carbonized cotton or some such substance forming a close pile, by reason of their
resiliency they will stand a fair amount of handling, however, when the projections
are of agglomerated fibres or powder carbonized they are very likely to be broken
or rubbed away.
To obviate this difficulty I construct the electrodes with guarding portions
attached to or formed of the substance of the said conducting support they being
so disposed upon and so far outstanding from the same as to prevent the fine
projections being damaged under any of the ordinary conditions which they might
be subject to.
I prefer to arrange that the said guarding portions be of some insulating
substance or (in the case of their being of the same material as the conducting
support or of other conducting material) that they be provided with an insulating
face, the said insulation serving to prevent accidental electric contact when the said
electrodes are in use.

page_text: My invention may be carried out in various ways among which are the
following:-
1
In the case of rods or tubes of conducting material covered with velvet carbon,
they may have a number of india rubber rings placed upon them at intervals, there
being a ring at each end of the pile covered portion, the depth of the rings being
of course greater than the depth of the carbon pile.
In the case of flat carbons, these may have ridge, band, or other projections of
the required depth moulded upon their surfaces during manufacture, cotton velvet
being subsequently attached to the flat surfaces between such ridge, band, or other
projections, and afterwards carbonised--the carbon projections being conductors of
electricity and likely to produce "short circuit" if the electrodes are used as battery
or electrolytic elements with no separating diaphragm or sufficient distance between
them and the element to which they are opposed their faces should be enamelled
with any suitable electricity non-conducting enamel varnish or other material.
In the case of carbon filaments cast into a lead backing, portions of earthen or
other non-conducting material may be placed in the mould before the lead is poured
so that when the metal is cast it shall incorporate a sufficient portion of the said
guarding substances so as to ensure their retention-the insulating guarding material
should be in the form of ridges, studs, or other suitable device, the precise form of
which must, however, together with the design of the electrode be determined after
consideration of the purpose for which the same is intended to be used.
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 :-
Claim I. The combination of an electrode consisting of a number of fine carbon
projections situated upon and outstanding from a carbonaceous or metallic conducting
support and one or more guarding portions attached to or formed of the substance
of the said conducting support substantially as and for the purpose described.
Claim II. The combination of an electrode consisting of a number of fine
carbon projections situated upon and outstanding from a carbonaceous or metallic
.conducting support certain portions of which are raised above the general surface
level for the purpose of protecting the fine carbon projections from injury, and a
coat of electricity insulating cement, enamel, or other suitable material upon the
outer surface or face of the said guarding portions substantially as and for the
purpose described.
Dated this 20th day of October 1893.
H. T. BARNETT.