Improvements in the Manufacture of Insulating Compositions for Electrical Purposes.
Year: 1895

page_text: Date of Application, 26th Nov., 1895
Complete Specification Left, 14th Jan., 1896-Accepted, 15th Feb., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Insulating Compositions for
Electrical Purposes.
I CHARLES JAMES GRIST of 20 Gracechurch Street in the City of London,
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
I take linseed or other drying oil and heat it up to at least 400° F. adding
litharge or other suitable drying agent taking care that it does not boil continuously
for more than six hours at any one time the whole of which time the oil is kept
continually in motion by suitable apparatus arranged either attached or conveniently
adjacent to the vessel containing it.
I then take a fibrous substance such as hemp, jute, cotton or suitable animal
fibre or other fibrous substance in which the fibres are or can be made to be distinct
and similar.
I then subject the fibres to a cleaning process such as carding.
The fibres now are spread and subjected to a drying process such as by means
of heated air propelled or drawn through them in order to remove as much as
possible any trace of aqueous moisture.
The oil having regained its normal temperature I take the fibres which have
been treated as above described, and immerse them in such oil immediately
removing them and placing them in a hydro-extractor or other suitable machine
for the purpose of extracting as much as possible all the superfluous oil, which is
then drained away.
The fibres will now be found to have small globules of partially oxidised oil
adhering at intervals on each fibre.
Then the fibres are spread loosely on wire gauze or netting and a current of
heated air is made to pass through them by means of a fan or other suitable
machine and in order that all the globules of oil in the fibres may be brought into
contact with the heated air as much as possible, the fibres must be turned or
redistributed in the netting about every hour. By these means nearly every
globule of oil adhering to the fibres is thoroughly oxidised and dried. When this
is accomplished I take the fibres and redip in the oil and when taken out of the
hydro-extractor it will be found that more globules of oil are adhering to the
fibres in the vacant spaces in between the former and already oxidised particles.
I repeat the drying process. A third and last time I dip the fibres and proceed
as before. I find that it is not expedient to dip more than three times because
most of the fibres being covered with globules of oxidised oil, should another dip
take place the unoxidised oil might coat and spread on the oxidised oil if this
happens the drying process cannot be thorough as the heated air would not be able
to play upon the whole of the unoxidised oil and oxidation being imperfectly
accomplished the resulting material would be worthless.
The fibres are now placed in masticating or grinding rolls, of different diameters,.
running at a high speed, and worked till they assume a homogeneous condition.
Then the material is placed in crushing rolls, which must not be heated, and at
least 15% to 20% of powdered sulphur should be added. Care must be taken
that the material is not allowed to get hot, by continually stripping it off the rolls
by means of a knife or gauge adapted to the purpose. When the sulphur is

page_text: thoroughly mixed with the composition the mixture is allowed to cool. I then
again place it in the crushing rolls when I may add gutta percha from 5% to 25%
as desired or wax or other suitable substance adapted to impart to the material
greater cohesion and consequent tenacity.
After the material has been rolled into sheets by means of heavy rolls or
callenders it can when cool be stored away till required, and is ready for use.
When it is necessary to soften the material for the coating of wire or other
purposes I take the sheets of material and again put them through the crushing
rolls. I then soak such reworked material in naptha, turpentine or other suitable
solvent and after thoroughly squeezing out the superfluous spirit, I again work
the same in the rolls until the composition is in such a soft and plastic condition
that it will adhere to the wire which is to be coated. The material can now be
placed in a wire-coating machine of the usual pattern for electrical purposes but
when the wire appears coated with the material it must be run through a hot air
chamber in order that any solvent spirit still retained in it may be evaporated.
Dated the 26th day of November 1895.
WM. BROOKES & SON,
55 & 56 Chancery Lane, London, Agents for the Applicant.
Improvements in the Manufacture of Insulating Compositions for
Electrical Purposes.
I CHARLES JAMES GRIST of 20 Gracechurch Street in the City of London,
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 :-
I take. linseed or other drying oil and heat it up to at least 400° F. adding
litharge or other suitable drying agent taking care that it does not boil con-
tinuously for more than six hours at any one time the whole of which time the oil
is kept continually in motion by suitable apparatus arranged either attached or
conveniently adjacent to the vessel containing it.
I then take a fibrous substance such as hemp, jute, cotton or suitable animal
fibre or other fibrous substances in which the fibres are or can be made to be
distinct and similar. I then subject the fibres to a cleaning process such as
carding. The fibres now are spread and subjected to a drying process such as by
means of heated air propelled or drawn through them in order to remove as much
as possible any trace of aqueous moisture.
The oil having regained its normal temperature I take the fibres, which have
been treated as above described, and immerse them in such oil immediately
removing them and placing them in a bydro-extractor or other suitable machine
for the purpose of extracting as much as possible all the superfluous oil, which is
thus drained away.
The fibres will now be found to have small globules of partially oxidised oil
adhering at intervals on each fibre.
Then the fibres are spread loosely on wire gauze or netting and a current of
heated air is made to pass through them by means of a fan or other suitable machine
and in order that all the globules of oil on the fibres may be brought into contact
with the heated air as much as possible, the fibres must be turned or redistributed
on the netting about every hour. By these means nearly every globule of oil
adhereing to the fibres is thoroughly oxidised and dried. When this is accom-
plished I take the fibres and redip in the oil and when taken out of the hydro-
extractor it will be found that more globules of oil are adhereing to the fibres in
the vacant spaces in between the former and already oxidised particles. 1 repeat
1

page_text: the drying and oxidising processes. A third and last time I dip the fibres and
proceed as before.
I find that it is not expedient to dip more than three times because most of the
fibres being covered with globules of oxidised oil, should another dip take place
the unoxidised oil might coat and spread on the oxidised oil and if this happens
the drying process can not be thorough as the heated air would not be able to
play upon the whole of the unoxidised oil and oxidation being imperfectly
accomplished the resulting material would be worthless.
The fibres are now placed in masticating or grinding rolls, of different
diameters, running at a high speed, and worked till they assume a homogeneous
condition.
Then the material is placed in crushing rolls, which must not be heated, and at
least 15% to 20% of powdered sulphur should be added, care must be taken that
the material is not allowed to get hot, by continually stripping it off the rolls by
means of a knife or gauge adapted to the purpose. When the sulphur is
thoroughly mixed with the composition the mixture is allowed to cool. I then
again place it in the crushing rolls when may add gutta percha from 5%
to 25% as desired or wax or other suitable substance adapted to impart to the
material greater cohesion and consequent tenacity. After the material has been
rolled into sheets by means of heavy rolls or callenders it can when cool be stored
away till required and is ready to be applied in any manner, after which it may
if desired be subjected to a process similar to that used for vulcanizing india
rubber.
When it is necessary to soften the material for the coating of wire or other
purposes I take the sheets of material and again put them through the crushing
rolls. I then soak such reworked material in naptha, turpentine or other suitable
solvent and after thoroughly squeezing out the superfluous spirit I again work the
same in the rolls until the composition is in such a soft and plastic condition that
it will adhere to the wire which is to be coated.
The material can now be placed in a wire-coating machine of the usual pattern
for electrical purposes but when the wire appears coated with the material it must
be run through a hot air chamber in order that any solvent spirit still retained in
it may be evaporated, and the material may then, as before, be subjected to a
vulcanizing process.
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:-
1. In the manufacture of insulating compositions for electrical purposes the
material resulting from the above described method of treating fibrous substances
with oil with the addition of at least fifteen per cent. of sulphur added as described
and the addition of gutta percha, or other suitable compounds adapted to give
enhanced tenacity all as and for the purpose set forth.
2. The method of manufacturing an insulating compound from fibres by coating
them with oil, oxidising, grinding with a large proportion of sulphur and then
vulcanizing, substantially as described.
Dated the 7th dow of Janua1806
WM. BROOKES & SON,
55 & 56 Chancery Lane, London, Agents for the Applicant.