Improvements in the Manufacture of Carbons or Electrodes for Electric Lamps.
Year: 1889

page_text: Date of Application, 1st June, 1889
Complete Specification Left, 1st Mar., 1890-Accepted, 5th Apr., 1890
[Communicated from abroad by Messrs. LACOMBE & Co., of 33, Rue de Lorraine
Levallois-Perret, near Paris, France, Manufacturers.]
Improvements in the Manufacture of Carbons or Electrodes for
Electric Lamps.
1, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature of
this invention to be as follows:-
This invention relates to the manufacture of carbons or electrodes for electric
lamps.
The said invention is chiefly designed to increase the efficiency of carbons or
electrodes made in the form of plates or discs, which, whilst occupying but a small
space in the lamp, contain a large volume of carbon for the maintenance of the
electric arc. My improvements are, however, also applicable to the manufacture of
other forms of carbons.
In the manufacture of carbons or electrodes according to the present invention, I
place between discs or other pieces or layers of carbon a layer of a material composed
of a mixture of carbonaceous and silicious substances, or any suitable composition or
material which, while not interfering with the proper working of the lamp, will by
reason of the better conduction of the electrical current ensure the retention of the
are in a fixed position and the consequent steadiness of the light. The pieces or
layers of carbon with the steadying substance above mentioned between them are
preferably subjected to a high degree of compression so as to consolidate the mass
and increase the density and homogeneity thereof and the duration of the electrodes.
Attempts have been made to employ discs of carbon for are lights, but these
attempts have failed by reason of the want of fixity of the are owing to the non-
employment of a substance such as that herein referred to. By the present invention,
however, plate or disc carbons can be manufactured with which a fixed or stable arc
and therefore a steady light can be maintained.
I am aware that carbon pencils have heretofore been manufactured which are
pierced with an axial opening and have inserted therein a mixture of refractory earth
and plumbago. These carbon pencils are, however, manufactured by forcing the
carbon through a die in the centre of which is placed a mandrel, the steadying sub-
stance being either introduced through the saidmandrel or inserted after the formation
of the carbon tube. It is evident that this method of making cored carbons is not
favorable to the efficient compression of the carbon and the obtainingofa high degree
of density, quite apart from the increased cost of manufacture.
In making my improved carbons or electrodes, I apply the above mentioned sub-
stance or composition in a liquid or in a pasty condition, or in the form of powder, or
I mould it to the desired shape before placing it between the two pieces or layers of
carbon, according to the method adopted for the manufacture of my improved carbons
or electrodes. Amongst the different methods which may be adopted for the manu-
facture of these electrodes, the following is given by way of example, viz.-One of
the two elementary discs or other pieces which are to constitute the electrode is
slightly compressed and then covered with a layer of the steadying substance or com-
position. The second disc or other piece prepared in the same manner as the first is
then placed above it and the whole is subjected to heavy pressure. The electrode is
then baked in the ordinary manner. It is obvious, however, that the manner of
combining the said substance or composition with the pieces of carbon may be
modified if desired.

page_text: Although I prefer to mould my said plate or disc carbons or electrodes under
pressure, yet it is obvious that a better carbon or electrode than those heretofore
manufactured can be made by uniting the component parts by chemical reaction,
adhesive material, or by baking, with or without the application of pressure.
I also sometimes form a spiral of carbon and, after extending the same in a plastic
state. I place the above mentioned substance between the convolutions thereof, and I
then compress the said spiral in any convenient manner. I thus produce an electrode
which can be conveniently employed in combination with a carbon rod or other
suitable electrode.
Data 1. 1.1
T1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
...
COMPLETE SPECIFICATION.
1
Improvements in the Manufacture of Carbons or Electrodes for
Electric Lamps.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, 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:-
This invention relates to the manufacture of carbons or electrodes for electric
lamps.
The said invention is chiefly designed to increase the efficiency of carbons or
electrodes made in the form of plates or discs, which, whilst occupying but a small
space in the lamp, contain a large volume of carbon for the maintenance of the
electric are.
My improvements are, however, also applicable to the manufacture of other forms
of carbons, although I prefer the discs above mentioned which are intended to be
arranged in pairs in combination with convenient devices for rotating them about
their axes so as to change the portions of their surfaces between which the arc is
formed, gradually until the whole of both circumferences have been used to any fixed
depth and a fresh rotation started, and so on until the discs have been so far consumed
as to render it impracticable to use them further.
In the manufacture of carbons or electrodes according to the present invention, I
place between discs or other pieces or layers of carbon, a layer of a material composed
of a mixture of carbonaceous and silicious substances, or any suitable composition or
material which, while not interfering with the proper working of the lamp, ensures
the retention of the are in a fixed position, and the consequent steadiness of the light.
The pieces or layers of carbon, with the steadying substance above mentioned between
them, are preferably subjected to a high degree of compression so as to consolidate
the mass and increase the density and homogeneity thereof and the duration of the
electrodes.
I am aware that attempts have been made to employ discs of carbon for are lights,
but these attempts have failed, amongst other reasons for the want of fixity of the are
owing to the non-employment of a steadying substance such as that herein referred
to. By the present invention, however, plate or disc carbons can be manufactured
with which a fixed or stable arc and therefore a steady light can be maintained.
I am also aware that carbon pencils have heretofore been manufactured which are
pierced with an axial opening and have inserted therein a mixture of refractory earth
and plumbago. These carbon pencils are, however, manufactured by forcing the
carbon through a die, in the centre of which is placed a mandrel, the steadying
substance being either introduced through, or by means of a hollow mandrel, or
inserted after the formation of the carbon tube. It is evident that this method of
making cored carbons is not so favourable to efficient compression of the carbons, and
the obtaining of a high degree of density.

page_text: In making my improved carbons or electrodes, I apply the above mentioned
steadying substance or composition in a liquid or in a pasty condition, or in the
form of powder, or I mould it to the desired shape before placing it between the two
pieces or layers of carbon, according to the method adopted for the manufacture of
my improved carbons or electrodes. Amongst the different methods which may be
adopted for the manufacture of these electrodes, the following are given by way of
examples, viz. According to one method, one of the two elementary dises or other
pieces which are to constitute the electrode, is first made by mixing powdered
carbon with suitable adhesive or agglutinating material and slightly compressing
it. This disc or other piece is then covered with a layer of the above mentioned
steadying substance or composition. The second disc or other piece prepared in the
same manner as the first, is then placed above it, and the whole is subjected to
heavy pressure, preferably in a suitable mould. The electrode is then baked in the
ordinary manner.
According to another method, 1 place in a suitable mould, a layer of carbon,
together with any suitable binding or agglutinating material, and I cover this layer of
carbon with the steadying substance or composition in a liquid or in a pasty
condition or in the form of powder; I then place thereon another layer of
carbon mixed with the adhesive material or agglutinant, and I cause an intimate
union of the two layers of carbon and the intervening steadying substance or
composition, by subjecting the whole to pressure in the said mould, or in any other
convenient manner, the electrode being baked in the usual manner.
It is obvious, however, that the manner of combining the said substance or composi-
tion with the pieces of carbon may be modified if desired.
Although I prefer to mould my said plate or disc carbons or electrodes under
pressure yet it is obvious that, in making my carbons or electrodes, I may employ
any means by which the parts above mentioned may be united, for instance, chemical
reaction, adhesive material, or baking with or without the application of pressure.
I also sometimes form a spiral or coil of carbon and, after extending the same in a
plastic state, I place the above mentioned steadying substance between the convolutions
thereof,and I then compress the said spiral lengthwise in any convenient manner so as
to form a cylindrical or other piece having the steadying substance extendinghelically
around the same. I thus produce an electrode which can be conveniently employed
in combination with a carbon rod or other suitable electrode.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I wish it understood
that I do not claim generally or irrespectively of my improvements herein described,
the employment in a carbon or electrode, of a steadying material or composition, as I
am aware that, in some cases, carbons have been made with a core of vitreous or other
material in order to ensure steadiness of the light; but I claim :—
First A carbon or electrode composed of plates or discs of carbon arranged side
by side and having between them a steadying substance or composition such as I have
herein before described, the whole being united by pressure or otherwise, for the
purpose above specified.
Second The improved method of manufacturing carbons or electrodes for electric
are lamps, consisting in first slightly compressing carbon mixed with a suitable
binding or agglutinating material and thus forming one of the elementary discs or
other pieces, then covering one side of the said disc or other piece with a layer of
the steadying substance or composition and placing thereon the second disc or other
piece prepared in the same manner as the first, and then subjecting the whole to heavy
pressure, and baking it, substantially as herein before described.
Third The improved method of manufacturing carbons or electrodes for electric
are lamps, consisting in placing in a suitable mould, a layer of carbon mixed with
binding or agglutinating material, covering this layer with the steadying substance or
composition and placing thereon a similar layer of carbon, and then uniting the whole
by pressure or otherwise, substantially as herein before described.

page_text: Fourth-A cylindrical or other carbon or electrode having the steadying
substance or composition extending helically around the same, substantially as
herein before described.
Fifth The herein described method of manufacturing carbons or electrodes for
electric are lamps, consisting in forming a spiral or coil of carbon, extending the same
longitudinally, placing between its convolutions the steadying substance or compo-
sition, and then effecting an intimate union between the convolutions and the
steadying material by pressure or otherwise, substantially as, and for the purpose,
described.
Dal 1.0041
11
1000
HASELTINE, LAKE & Co..
45, Southampton Buildings, London, Agents for the Applicant.