IMPROVEMENTS IN ELECTRIC CONDUCTORS, AND IN A COMPOUND OR COMPOUNDS FOR PREVENTING THE DETERIORATION OF RUBBER INSULATORS
Year: 1880

page_text: LETTERS PATENT to George Barker, of 77, Colmore Row, Birmingham, in the
County of Warwick, Consulting Engineer and Patent Agent, for an Invention
of "IMPROVEMENTS IN ELECTRIC CONDUCTORS, AND IN A COMPOUND OR
COMPOUNDS FOR PREVENTING THE DETERIORATION OF RUBBER INSULATORS."
A communication from abroad by William W. Jacques, of the City of Boston,
State of Massachusetts, America.
PROVISIONAL SPECIFICATION left by the said George Barker at the Office
of the Commissioners of Patents on the 24th August 1880.
GEORGE BARKER, of 77, Colmore Row, Birmingham, in the County of Warwick,
Consulting Engineer and Patent Agent. "IMPROVEMENTS IN ELECTRIC CONDUCTORS,
AND IN A COMPOUND OR COMPOUNDS FOR PREVENTING THE DETERIORATION OF
RUBBER INSULATORS." [A communication from abroad by William W. Jacques, of
the City of Boston, State of Massachusetts, America.]
The object of this Invention is to provide an insulating coating for telegraph
wires and other electric conductors which shall have a high insulating power and
at the same time be tough, pliable, and elastic under any conditions of temperature
or weather to which it would naturally be exposed, which shall be entirely
impermeable to water, gases, and moisture, and not affected by atmospheric
influences nor liable to change with time, and, finally, which shall be much cheaper
than substances usually employed for the same purpose.
The covering is composed of rubber which has been subjected to a peculiar
process whereby a substance is mixed with it that imparts to the rubber certain
desirable qualities, practically that of durability; with this prepared rubber may
be mixed a considerable quantity of one or more of the cheap substances ordinarily
used to increase the bulk of the mass at small cost, such as oxide of zinc, litharge,
steatite, or asphalt; sulphur is also used in the usual proportions in order that it
may be vulcanized.

page_text: It is well known among scientific men that the decay observed in rubber,
particularly when exposed to the sun and atmospheric influences, is one of
oxidation, whereby the hydrocarbon of the approximate composition carbon 90,
hydrogen 10, is converted into an oxide of the approximate composition carbon 64,
hydrogen S, oxygen 38, that is, the rubber takes into combination with itself,
chemically, about one quarter of its weight of oxygen, and the peculiar product is
crystaline in structure, brittle, permeable to fluids, and entirely unfit for an insulating
coating for telegraph wires.
I have discovered that rubber, either pure or mixed with the ordinary dilutants,
has the power of taking considerable quantities of oxygen from the air or water
into actual solution in itself and of condensing this oxygen in its pores.
The oxygen so dissolved and condensed is nearly pure and in active condition to
combine chemically with the rubber and destroy its valuable properties. The
chemical union goes on most rapidly when the rubber is exposed to air and sunlight,
and the process that I have invented destroys the solvent and absorbent power of
the rubber, fills up the pores, and prevents decay.
It consists in thoroughly impregnating the pores of the rubber, by a process
hereinafter set forth, with a mixture of about equal parts of Venice turpentine and
beeswax, though the proportion of the ingredients may be considerably varied, and
then of coating this impregnated rubber with more of the preserving compound,
sulphur, and various dilutants, by continued working on warm rolls.
The substance thus obtained is applied to the wire by known processes and then
vulcanized in the usual way. In carrying out the process I take a vessel
conveniently arranged to be heated and to exclude the air by exhaustion through
the means of a suitable air-pump, and heat the preserving compound in the vessel
to about 80° C.
The rubber is then added in the form of sheets, or better in the form known as
"cracked rubber," and is submerged in the compound. The heat is then gradually
raised to about 100° C., the air at the same time being gradually exhausted from the
vessel and consequently from the pores of the rubber. I then admit the air and
allow the mass to cool to about 80° C., and remove the rubber, which will have
absorbed from 20 to 30 per cent. of the compound.
Rubber so prepared will be found to have lost its power of absorption and to
have its insulating power and impermeability to water and moisture greatly
increased. It is also fitted to take up a larger proportion of cheapening dilutants
without losing its essential properties as a coating for wires. The rubber thus
impregnated with the preserving compound is now mixed on warm rolls in the
usual way with powdered sulphur enough to allow of vulcanization, and with an
equal weight or more of some cheap substance to give bulk to the mass.
Powdered steatite or asphalt answers the purpose very well and their cost is but
trifling. A composition that I have found to give good results and to be at the
same time cheap consists of,-
Rubber
Preserving compound-
Sulphur
Oxide of zinc
Steatite
Asphalt
30 parts.
7 parts.
3 parts.
-
10 parts.
10 parts.
40 parts.

page_text: finally drawn through a die in a manner similar to that in which wires are covered
with gutta percha.
As an alternative for this method the composition may be rolled into sheets, with
which the wires are afterwards covered, or other well known means may be resorted
to in order to coat the wires.
The coated wires are finally packed in powdered soapstone and vulcanized in the
usual way. It is obvious that my Invention is not limited to the single application
of the prepared rubber herein before set forth, namely, the coating of electric
conductors. Given the result of my discovery, and the properties of the new
composition embodying the same; numerous uses to which the new composition are
applicable suggest themselves.
Instead of coating the wires with the prepared rubber they may be coated with
the rubber compound in the usual way, the coating being subsequently impregnated
with the preserving compound, as described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Barker in the Great Seal Patent Office on the 22nd
February 1881.
GEORGE BARKER, of 77, Colmore Row, Birmingham, in the County of Warwick,
Consulting Engineer and Patent Agent. "IMPROVEMENTS IN ELECTRIC CONDUCTORS
AND IN A COMPOUND OR COMPOUNDS FOR PREVENTING THE DETERIORATION OF
RUBBER INSULATORS." (A communication from abroad by William W. Jacques, of
the City of Boston, State of Massachusetts, America.)
The object of this Invention is to provide an insulating coating for telegraph
wires and other electric conductors which shall have a high insulating power, and
at the same time be tough, pliable, and elastic under any conditions of temperature
or weather to which it would naturally be exposed, which shall be entirely imper-
meable to water, gases, and moisture, and not affected by atmosphere influence, nor
liable to change with time, and, finally, which shall be much cheaper than
substances usually employed for the same purpose.
The covering is composed of rubber which has been subjected to a peculiar
process, whereby a substance is mixed with it that imparts to the rubber certain
desirable qualities, practically that of durability; with this prepared rubber may
be mixed a considerable quantity of one or more of the cheap substances ordinarily
used to increase the bulk of the mass at small cost, such as oxide of zinc, litharge,
steatite, or asphalt; sulphur is also used in the usual proportions, in order that it
may be vulcanized.
It is well known among scientific men that the decay observed in rubber,
particularly when exposed to the sun and atmospheric influences, is one of oxidation,
whereby the hydrocarbon of the approximate composition carbon 90, hydrogen 10,
is converted into an oxide of the approximate composition carbon 64, hydrogen S,
oxygen 38, that is, the rubber takes into combination with itself, chemically, about
one quarter of its weight of oxygen, and the peculiar product is crystaline in
structure, brittle, permeable to fluids, and entirely unfit for an insulating coating
for telegraph wires.
I have discovered that rubber, either pure or mixed with the ordinary dilutants,
has the power of taking considerable quantities of oxygen from the air or water
into actual solution in itself, and of condensing this oxygen in its pores.
The oxygen so dissolved and condensed is nearly pure, and in active condition
to combine chemically with the rubber and destroy its valuable properties. The
chemical union goes on most rapidly when the rubber is exposed to air and
sunlight, and the process that I have invented destroys the solvent and absorbent
power of the rubber, fills up the pores, and prevents decay.
It consists in thoroughly impregnating the pores of the rubber, by a process
hereinafter set forth, with a mixture of about equal parts of Venice turpentine and
bees-wax, though the proportion of the ingredients may be considerably varied, and
then of coating this impregnated rubber with more of the preserving compound,
sulphur, and various dilutants by continued working on warm rolls.
The substance thus obtained is applied to the wire by known processes, and then
vulcanized in the usual way. In carrying out the process I take a vessel con-
veniently arranged to be heated, and to exclude the air by exhaustion through the
means of a suitable air pump, and heat the preserving compound in the vessel to
about 80° C.
The rubber is then added in the form of sheets, or better in the form known as
"cracked rubber," and is submerged in the compound. The heat is then gradually

page_text: 100
Ia mixing the rubber with the dilutants, it is well to add a small quantity of the
preserving compound also; the whole must in any case be thoroughly mixed by
long continued working on rolls.
The substance being prepared in the way described, is formed upon the wire that
it is desired to insulate by running the wire through a chamber heated to
about 100° C., and containing the prepared rubber under pressure, the wire being
finally drawn through a die in a manner similar to that in which wires are covered
with gutta percha.
As an alternative for this method, the composition may be rolled into sheets,
with which the wires are afterwards covered, or other well known means may be
resorted to in order to coat the wires.
The coated wires are finally packed in powdered soapstone and vulcanized in the
usual way. It is obvious that my Invention is not limited to the single application
of the prepared rubber herein before set forth, namely, the coating of electric
conductors gives, the result of my discovery, and the properties of the new com-
position embodying the same; numerous uses to which the new composition are
applicable suggest themselves.
Instead of coating the wires with the prepared rubber, they may be coated with
the rubber compound in the usual way, the coating being subsequently impregnated
with the preserving compound as described.
Having thus fully described the said Invention of improvements in electric
conductors, and in a compound or compounds for preventing the deterioration of
rubber insulators, as communicated to me by my foreign correspondent, and the
manner of performing the same, I wish it to be understood that I claim as my
Invention,
First. As an article of manufacture an electric conductor, consisting of a metalic
core coated with a compound containing rubber, beeswax, and Venice turpentine, as
set forth.
Second. The composition herein described, consisting of rubber, Venice turpentine,
and beeswax, with a without dilutants, substantially as and for the purpose set
forth.
Third. The process herein described for preventing the deterioration or decay of
rubber insulators, consisting in subjecting the same to diminished pressure in
presence of a preservative composition, whereby the pores of the rubber are opened,

page_text: and finally increasing the pressure in order to force the preservative into the pores,
as described.
In witness whereof, I, the said George Barker, have hereunto set my hand
and seal, this Twenty first day of February, in the year of our Lord One
thousand eight hundred and eighty one.
JOSEPH HENRY PEARSON,
Clerk to George Barker,
Consulting Engineer & Patent Agent,
77, Colmore Row,
Birmingham.
GEORGE BARKER. (L.S.)