Improvements in or relating to Electric Cables.
Year: 1899

page_text: PROVISIONAL SPECIFICATION..
Improvements in or relating to Electric Cables.
I, GEORGE EDWARD HEYL-DIA, of 55, Market Street, Manchester, in the County
of Lancaster, Engineer, do hereby declare the nature of this invention to be
as follows:
Paper insulated cables as at present manufactured absorb moisture if their
ends are left open, thus giving cause for break downs and bad insulation tests,
and they are entirely dependent on their lead covering. Should this covering
get pierced or should the lead covering be faulty from any cause the cable is
liable to speedily break down, as the dampness in the ground penetrates into the
paper insulation. The so-called paper cables are usually covered with paper
which has been impregnated with resin oil. As this remains in the cable in
the liquid form it is evident that unless the cable be completely filled, which
is usually impracticable, it will run down and collect in the lowest part of the
cable leaving the higher portions with the paper dry. It is essential therefore
that the resinoil paper cables should be laid in the ground as level as possible
to avoid break downs through the paper being drained dry in places. It is a
fact that many break downs have taken place for the reasons above mentioned.
The lead covering is also frequently attacked and corroded, by chemicals which
are found in many oils. In consequence of these facts the paper cable of to-
day cannot be considered reliable under all circumstances. The method of
insulation which I am now about to describe is designed to avoid these difficulties
and dangers and to obtain an insulation which will combine in itself all the
good qualities of paper more especially its high resistence against high tensional
currents, the impregnated paper also being applied in a semi dry state, the
layers of paper adhere to each other, so that moisture cannot creep up if the
ends are left open. This paper is made as described in my former Patent,
No. 2610 of 1899 or it is impregnated with oils under application of heat to
expel moisture, and of such character that they will gelatinise if exposed to the
action of oxygen.
A highly insulated paper is thus obtained and the sheeting
of gelatinized oil such as oxidized linseed, rape, or other oxidizable oil, oxidized
after the paper has been impregnated with the ordinary unoxidized or only
partially oxidized oil, the oxidation being preferably performed by hot air cur-
rents which act on the oil sheeting while the paper is hung up, thus solidifying
it. The oil coating may be varied in thickness according to the number of
impregnations or coverings the paper is submitted to, it being understood that
the paper is subjected to oxidation after each covering with oil. Paper made
into a good insulator by this method is cut up into strips and put on the cable
strand in any ordinary way, but to further safeguard the cable against water
getting into the insulation by the lead covering giving way, the lays of paper
may be interleaved with a sheathing of rubber, gutta percha, pitch compound
containing sulphur or the like. After several concentric lays of paper, one layer
is laid on of the vulcanized composition, lapped on double lap, so as to make

page_text: a thin tube all over the paper covering, then again follows several lays of paper,
then again a sheathing of vulcanized composition, and so on until the thickness
of insulation desired has been obtained. The cable is then exposed to a gentle
heat so so to vulcanize the vulcanizing composition sheathings into a solid tube.
Should the lead coverings be damaged in this case it would not effect the insu-
lating qualities at all as the semi liquid or viscous oil insulation and the rubber
or pitch composition forming a solid tube all round the conductor and paper
prevents any moisture from creeping into the paper. Instead of vulcanizing
compositions, other compositions may be used which will form a solid tube by
their natural adhesiveness, one spiral or longitudinal lay sticking to the other.
Such compositions are made for instance from low class gums like balata,
potato rubber and the like, care being taken of course that such compositions
shall be non-conducting.
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01
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1000
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
I, GEORGE EDWARD HEYL-DIA, of 55, Market Street, Manchester, in the County
of Lancaster, 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:―
Paper insulated cables as at present manufactured absorb moisture if their
ends are left open.. thus giving cause for break downs, and bad insulation tests.
They are in fact almost entirely dependent on their lead covering. Should this
covering get pierced or should the lead cover be faulty from any cause, the
cable is liable to speedily break down, as the dampness in the ground pene-
trates into the paper insulation. The insulation paper of these so-called paper
cables is usually impregnated with resin oil. As this oil remains in the cable
in the liquid form it is evident that unless the cable be completely filled, which
is usually impracticable, it will run down and collect on the lowest part of the
cable leaving the higher portions practically destitute of oil. It is essential
therefore that the resin oil paper cables should be laid in the ground as level as
possible to avoid break downs through the paper being drained dry in places.
It is a fact that many break downs have taken place for reasons above mentioned.
The lead covering is also frequently attacked and corroded by chemicals which
are found in many soils, and sometimes in the oils used. In consequence of
these facts the paper cables of to-day cannot be considered reliable under all
circumstances.
Now my invention is designed to avoid the dangers and evils above mentioned,
and to obtain an insulation which will combine in itself all the good qualities
of the ordinary paper insulation, especially its high resistance against high
tension currents, and yet avoid these difficulties and dangers.
My impregnated paper is applied in a semi dry state, the layers of paper
adhere to each other so that moisture cannot creep up if the ends be left open.
or the lead be perforated. This paper is made as described in my previous
Specification, No. 2610 of 1899, or it is impregnated with oils while under or
immediately after application of heat to expel moisture and the oil being gela-
tinized by exposure to oxygen a highly insulated paper is thus obtained. The

page_text: sheeting of gelatinized oil such as oxidized linseed, rape, or other oxidizable
oil, is oxidized after the paper has been impregnated with unoxidized or partially
oxidized oil, the operation being preferably performed by hot air currents which
act on the oil sheeting while the paper is hung up, thus solidifying it. The oil
coating may be varied in thickness by varying the number of impregnations or
coverings to which the paper is submitted, it being understood that the paper is
subjected to oxidation after each covering with oil. Paper is made into a
good insulator by this method and then cut into strips or it can be cut into strips
first, and then subjected to the impregnation. The strips are put on the cable
strand in any ordinary way. To further safeguard the cable against water
getting into the insulation by the lead covering giving way, the lays of paper
are preferably interleaved with a sheathing of rubber, gutta percha, or a pitch
compound containing sulphur, or the like vulcanized. After several concentric
lays of paper, one layer is laid on of the vulcanized composition, lapped on
double lap, so as to make a thin tube all over the paper covering. This is
covered by several more lays of paper, then again by a sheathing of the vulcanized
composition and so on until the thickness of insulation desired has been obtained.
The cable is then preferably exposed to a gentle heat so as to vulcanize the
vulcanizing composition sheathings into a solid tube. Should the lead coverings
be damaged in such a cable as this, it would not affect the insulating qualities
at all, as the gelatinous or viscous oil insulation and the rubber or pitch compo-
sition forming a solid tube all round the conductor and paper, prevent any mois-
ture from creeping into the paper or getting to the conductor. Instead of
vulcanizing compositions, very soft rubber or other compositions may be used
which will form a solid tube by their natural adhesiveness, one spiral or longi-
tudinal lay sticking to the other. Such compositions are made for instance
from low class gums like balata, potato rubber or the like, care being taken
to only use such compositions are are non-conducting. In thus speaking of
paper, it must be clearly understood that the word is intended to include any
long strips or ribbons of fibrous non-conducting materials whether the said
ribbons are made in a paper machine, a felting machine, or by any other mech
anism, or by hand, but so that the strip be formed of cellulose material with
sufficient longitudinal strength for the purposes described.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is:
1. The improvement in the manufacture of electric cables which consists in
forming the insulation thereof of long strips of paper coated with gelatinous oil
and laid on the cable in several lavers in such manner that the various layers
shall each form a tube and shall adhere to each other, substantially as described.
2. In a cable, substantially as described in Claim 1, the combination with
one or more sheathings of vulcanized composition, rubber, or the like, substan-
tially as described.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.