AN IMPROVED MANUFACTURE OF MATERIAL FOR ELECTRICAL INSULATION
Year: 1882

page_text: LETTERS PATENT to John Imray of No 28 Southampton Buildings Chancery
Lane in the County of Middlesex, for an invention of "AN IMPROVED
MANUFACTURE OF MATERIAL FOR ELECTRICAL INSULATION."-A communication
from abroad by La Sociètè Anonyme des Cables electriquès (Systeme Berthoud,
PROVISIONAL SPECIFICATION left by the said John Imray at the Office of
the Commissioners of Patents on the 29th March 1882.
JOHN IMRAY of No 28 Southampton Buildings Chancery Lane in the County of
Middlesex 66
AN IMPROVED MANUFACTURE OF MATERIAL FOR ELECTRICAL INSU-
LATION." [A communication from abroad by La Sociètè Anonyme des Cables
electriques (Systeme Berthoud, Borel et Cie) of Paris in the Republic of France
an incorporated company.]
This invention relates to the production of a material for electrical insulation
consisting mainly in the transformation of a siccative oil into a solid elastic
body.
The process employed by preference for the production of this material is as
follows:-
A quantity of siccative linseed oil is heated to boiling point or about 320°
Centigrade in a metal vessel, which is open so that the oil can be continually stirred
so that the part in contact with the atmosphere is always being changed. The oil
becomes gradually of a darker colour, and at the end of a certain time which may
vary from twenty minutes to several hours, according to the quality of the oil this
becomes transformed into a solid elastic mass similar to caoutchouc. This
material by itself gives an insulation which is not perfect, and it has been found
that colophonium mixed with the oil at the moment when the transformation from
a liquid to a solid state commences, gives a material that has the same degree of
insulation as the mixture of colophonium and paraffine which has been employed
as insulating coating for telegraph cables.

page_text: The quantity of colophonium to be added depends upon the degree of hardness
which it is desired to impart to the material.
With equal parts of colophonium and of oil a very elastic material of a high
degree of insulation is obtained, which does not harden at a low temperature.
If the proportion of colophonium be increased the material becomes rather brittle.
The chemical action involved in the transformation of the liquid oil into a solid
is generally admitted to consist of the oxidation of the oil in contact with the air.
It is possible that this may be correct, but it is probable that there is also a
molecular transformation involved.
The material prepared as described either from pure linseed oil or from a mixture
of this oil with colophonium, can either be applied by known methods directly as
an insulating coating to the telegraphic wires, or it may be used to impregnate textile
fabrics used as a sheathing to the conductors.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Imray in the Great Seal Patent Office on the 29th September
1882.
"
JOHN IMRAY of No. 28 Southampton Buildings Chancery Lane in the County of
Middlesex "AN IMPROVED MANUFACTURE OF MATERIAL FOR ELECTRICAL INSU-
LATION A communication from abroad by La Sociètè Anonyme des Cables
electriques (système Berthoud, Borel et Cie) of Paris in the Republic of France
an incorporated Company.
This invention relates to the production of a material for electrical insulation
consisting mainly in the transformation of a siccative oil into a solid elastic
body.
The process employed by preference for the production of this material is as
follows: A quantity of siccative linseed oil is heated to boiling point or about
320° Centigrade in a metal vessel, which is open so that the oil can be continually
stirred in order that the part in contact with the atmosphere may be continually
changed. The oil becomes gradually of a darker colour, and at the end of a certain
time which may vary from twenty minutes to several hours, according to the
quality of the oil, this becomes transformed into a solid elastic mass similar to
caoutchouc. This material by itself gives an insulation which is not perfect, and
it has been found that colophonium mixed with the oil at the moment when the
transformation from a liquid to a solid state commences, gives a material that has
the same degree of insulation as the mixture of colophonium and paraffin which
has been employed as insulating coating for telegraph cables.
The quantity of colophonium to be added depends upon the degree of hardness
which it is desired to impart to the material.
With equal parts of colophonium and of oil a very elastic material of a high
degree of insulation is obtained, which does not harden at a low temperature. If
the proportion of colophonium be increased the material becomes rather brittle.
The chemical action involved in the transformation of the liquid oil into a solid
is generally admitted to consist of the oxidation of the oil in contact with the air.
It is possible that this may be correct, but it is probable that there is also a
molecular transforination involved.
The material prepared as described either from pure linseed oil or from a mixture
of this oil with colophonium, can either be applied by known methods directly as
an insulating coating to the telegraphic wires, or it may be used to impregnate
textile fabrics used as a sheathing to to the conductors.
Having thus described the nature of the said invention and in what manner the
same is to be performed as communicated to me by my foreign correspondents, I
claim:
The herein described improved manufacture of material for electrical insulation,
consisting of linseed oil converted into a solid elastic body by the application of
heat, with or without admixture of colophonium.
In Witness whereof I the said John Imray have hereunto set my hand and
seal this twenty ninth day of September in the year of our Lord Ons
thousand eight hundred and eighty two.
JOHN IMRAY (L.S.)