Year: 1894

page_text: Date of Application, 7th Sept., 1894
Complete Specification Left, 8th July, 1895-Accepted, 10th Aug.,
1895
I, SEBASTIAN ZIANI DE FERRANTI of Charterhouse Square in the County of
London, Electrical Engineer, do hereby declare the nature of this invention to be
as follows:-
My improvements relate specially to that class of cable in which the conductors
are surrounded as much as possible by air, so as to lower their capacity and so
facilitate their quick working.
According to my invention I pass the wire to be insulated through a tube
mandrel. Upon this mandrel I wind paper, the edge of which has been treated
with some sticky material. I prefer to burnish this down either with a friction
cramp or with heated metal rubbers. The tube mandrel may either stand or
revolve, as is found best suited to the particular manufacture.
In some cases I form the tube mandrel with a screw on it, and the burnisher
with longitudinal grooves on it, in which case I run the tube so that the screw
helps to feed the paper tube off the mandrel as it is formed. In some cases
I may form a screw thread inside the burnisher instead of on the mandrel, and
run the burnisher, or both the burnisher and tube mandrel may be screwed, and
both run in opposite directions, to feed the paper or insulating tube off as it
is made.
In some cases I use a longitudinal paper gummed or treated on the edge with
some sticky material, to form a groundwork for the spiral paper and to assist in
drawing off. I may also use several papers so as to make a stiffer tube, and these
papers may be laid in opposite directions where found necessary. I prefer in all
these cases to stick the papers together so as to increase their stiffness and prevent
their collapsing when made up into a cable, and so keep the maximum air space
around the conductors. In some cases 1 treat the paper, as it is being laid on,
with a stiffening solution which may be dried by hot rubbers as laid on the
mandrel and which gives the paper tube greater stiffness and a better chance of
maintaining its shape.
The wires surrounded by their tubes may be bunched together to form a cable,
or they may be stranded in pairs or fours and then laid together, or they may be
formed into a cable in any of the well known methods. The tubes will take up an
irregular shape according to their position in the cable.
Whenever I have mentioned the use of paper, I may in certain cases use ebonite
or hard rubber, and stick the edges together with a vulcanising solution which is
fixed partly by the heated mandrel and rubbers and also by being cooked after-
wards, or the ebonite itself may be only partially cured and the process finished
after the tube or cable is made up.
Where the air space cables are used for submarine work, the insulation is
subjected to great pressure from the water. The object of my invention is to
provide an insulating non-compressible tube under the insulation of gutta percha
or india rubber.
According to one method, I effect this object by passing the wire through a
tube mandrel on which I form a paper tube, sticking each layer together with a
hard cement and drying same as the process proceeds, in this way I build up a tube
of great strength.

page_text: On this I lay a strip or strips of gutta percha and make good the joint with a
bot iron. The cable may then be passed through a gutta percha press, and
additional layers of gutta percha laid on in the ordinary way to make up the core.
The cable is afterwards finished and armoured.
Or I may take the paper tube as above explained and lay on longitudinally or
spirally pure or vulcanised as is commonly done in the manufacture of cables
insulated with rubber. This may be vulcanised or finished vulcanising by heat
which must not be great enough to destroy the paper tube.
The cable is then armoured and finished for laying in the ordinary way.
According to another method, I may form the insulating supporting tube to
contain the wire by passing the wire through a hollow mandrel on to which is
wound a strip of ebonite spirally.
This ebonite or equivalent material may be of square section, or it may be
formed with a projection on one edge and a recess on the other, so that, when wound
and pressed along on the mandrel, each turn will lock into the next and so form a
solid and yet flexible tube.
The ebonite may be made in a two-step section, or in such a form that, when
wound, it will lock sideways, or it may have tapered edges, so that, when wound,
each layer overlaps the next so as to give the maximum support to the insulation
covering the supporting tube.
In some cases I form the supporting tube out of a longitudinal strip, preferably
with registering or tongue and groove edges and form it through a die which may
be assisted by heat into a tube around the wire.
A tube formed of several layers, preferably breaking joint with each other, may
be made in this way.
In all of the above cases, the edges of the material out of which the tube is
formed may be treated with the vulcanising solution, which may be heated
sufficiently to add to the solidity of the supporting insulating tube.
Any of the supporting tubes as above described may be covered with india
rubber, which may be afterwards vulcanised, or they may be covered with gutta
percha pressed on in the ordinary way.
According to another method, I may form the tube of ebonite by pressing an
unvulcanised or partially vulcanised preparation of rubber or some equivalent
material through a core and die around the wire, and afterwards finishing the
hardening of the tube either by heat on the mandrel as the tube is pressed, or by
further curing after the rubber insulation has been laid on. Or, if the insula-
tion is to be formed of gutta percha, then the tube of ebonite or equivalent
composition must be finished by vulcanising or otherwise before the gutta percha
is applied.
In other cases where gutta pei cha is to be used as the insulator, I form the tube
of a special grade of gutta percha of the hardest kind, and which would be too
hard and brittle to cover a wire with insulation in the ordinary way. This I squirt
over the wire in one or more layers, leaving the necessary air space between it and
the wire, and then apply as many layers as necessary of the best gutta percha of
the usual quality used in the manufacture of the submarine cables.
In some cases, I form the inside of the tube with ridges or projections, preferably
at an angle of 120 degrees from each other, to support the wire.
Where more than one conductor is used in the cable, I form the conductors
round a core of ebonite or some other material preferably which will not absorb
moisture. This core may be made in the form of a cross where four wires are
used, and the hollow mandrel may be cut out to feed this through with the wires as
the supporting tube is formed. Or I may lay the wires together with each wire
twisted round with string or with a strip of ebonite or hard rubber to keep the
wires apart.
In all these cases I apply one or other of the forms of supporting insulating
tubes, insulated and finished as above described.
In all cases I prefer to so construct cables according to my invention that the

page_text: air space surrounding the wire may be most definite and may best retain its
shape; so that the supporting tube enclosing the conductor and the air space may
be strong enough to resist the maximum pressure, may be a good insulator, may
not absorb moisture (or may be so worked that the moisture may be driven off
during the process before the insulation is put on) and may be of the minimum
weight, and so that the insulation is so laid on the supporting tube as to efficiently
insulate and waterproof the cable.
Dated this 6th day of September 1894.
I, SEBASTIAN ZIANI DE FERRANTI of Charterhouse Square in the County 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:-
My improvements relate specially to that class of cable in which the conductors
are surrounded as much as possible by air, so as to lower their capacity and so
facilitate their quick working.
According to my invention I pass the wire to be insulated through a tube
mandrel. Upon this mandrel I wind paper, the edge of which has been treated
with some sticky material. I prefer to burnish this down either with a friction
cramp or with heated metal rubbers. The tube mandrel may either stand or
revolve, as is found best suited to the particular manufacture.
In some cases I form the tube mandrel with a screw on it, and the burnisher
with longitudinal grooves on it, in which case I run the tube so that the screw
helps to feed the paper tube off the mandrel as it is formed. In some cases I may
form a screw thread inside the burnisher instead of on the mandrel, and run the
burnisher, or both the burnisher and tube mandrel may be screwed, and both run
in opposite directions, to feed the paper or insulating tube off as it is made.
In some cases I use a longitudinal paper gummed or treated on the edge with
some sticky material, to form a ground work for the spiral paper and to assist in
drawing off. I may also use several papers so as to make a stiffer tube. and these
papers may be laid in opposite directions where found necessary. I prefer in all
these cases to stick the papers together so as to increase their stiffness and prevent
their collapsing when made up into a cable, and so keep the maximum air space
around the conductors. In some cases I treat the paper, as it is being laid on,
with a stiffening solution which may be dried by hot rubbers as laid on the mandrel
and which gives the paper tube greater stiffness and a better chance of maintaining
its shape.
together to form a cable,
together, or they may be
The tubes will take up an
The wires surrounded by their tubes may be bunclied
or they may be stranded in pairs or fours and then laid
formed into a cable in any of the well known methods.
irregular shape according to their position in the cable.
Whenever I have mentioned the use of paper, I may in certain cases use ebonite
or hard rubber, and stick the edges together with a vulcanising solution which is
fixed partly by the heated mandrel and rubbers and also by being cooked after-
wards, or the ebonite itself may be only partially cured and the process finished
after the tube or cable is made up.
Where the air space cables are used for submarine work, the insulation is
subjected to great pressure from the water. The object of my invention is to

page_text: provide an insulating non-compressible tube under the insulation of gutta percha or
india rubber.
According to one method. I effect this object by passing the wire through a tube
mandrel on which I form a paper tube, sticking each layer together with a hard
cement and drying same as the process proceeds, in this way I build up a tube of
great strength.
On this I lay a strip or strips of gutta percha and make good the joint with a
hot iron. The cable may then be passed through a gutta percha press, and
additional layers of gutta percha laid on in the ordinary way to make up the core.
The cable is afterwards finished and armoured.
Or I may take the paper tube as above explained and lay on longitudinally or
spirally pure or vulcanised rubber as is commonly done in the manufacture of
cables insulated with rubber. This may be vulcanised or finished vulcanising by
heat which must not be great enough to destroy the paper tube.
The cable is then armoured and finished for laying in the ordinary way.
According to another method, I may form the insulating supporting tube to
contain the wire by passing the wire through a hollow mandrel on to which is
wound a strip of ebonite spirally.
This ebonite or equivalent material may be of square section, or it may be
formed with a projection on one edge and a recess on the other, so that, when
wound and pressed along on the mandrel, each turn will lock into the next and so
form a solid and yet flexible tube. These two forms of insulation are shown in
longitudinal section, Figures 1 and 2.
The ebonite may be made in a two-step section, as shown in longitudinal section
Figure 3 or in such a form that, when wound, it will lock sideways, as shown in
Figure 4, or it may have tapered edges, so that, when wound, each layer overlaps
the next so as to give the maximum support to the insulation covering the
supporting tube. This is set forth in Figure 5.
In some cases I form the supporting tube out of a longitudinal strip, preferably
with registering or tongue and groove edges and form it through a die which may
be assisted by heat into a tube around the wire, as set forth with registering edges
in Figure 6 transverse section or with tongue and groove edges as in Figure 7.
A tube formed of several layers, preferably breaking joint with each other, may
be made in this way, this is shown in Figure 8.
Figures 9 and 10 show two views of a cable built up as set forth in Figure 1 but
in which there are four spirals and one of these has an internal projecting edge so
as to touch or nearly touch the wire all along and thus keep it in the centre of the
spiral.
In all of the above cases, the edges of the material out of which the tube is
formed may be treated with the vulcanising solution, which may be heated
sufficiently to add to the solidity of the supporting insulating tube.
Any of the supporting tubes as above described may be covered with india
rubber, which may be afterwards vulcanised, or they may be covered with gutta
percha pressed on in the ordinary way.
According to another method, I may form the tube of ebonite by pressing an
unvulcanised or partially vulcanised preparation of rubber or some equivalent
material through a core and die around the wire, and afterwards finishing the
hardening of the tube either by heat on the mandrel as the tube is pressed, or by
further curing after the rubber insulation has been laid on. Or, if the insulation is
to be formed of gutta percha, then the tube of ebonite or equivalent composition
must be finished by vulcanising or otherwise before the gutta percha is applied.
In other cases where gutta percha is to be used as the insulator, I form the tube
of a special grade of gutta percha of the hardest kind, and which would be too
hard and brittle to cover a wire with insulation in the ordinary way. This I squirt
over the wire in one or more layers, leaving the necessary air space between it and
the wire, and then apply as many layers as necessary of the best gutta percha of
the usual quality used in the manufacture of the submarine cables.

page_text: In some cases, I form the inside of the tube with ridges or projections, preferably
at an angle of 120 degrees from each other, to support the wire, when it will have
a cross section similar to Figure 10.
Where more than one conductor is used in the cable, I form the conductors
round a core of ebonite or some other material preferably which will not absorb
moisture. This core may be made in the form of a cross where four wires are used,
and the hollow mandrel may be cut out to feed this through with the wires as the
supporting tube is formed. Or I may lay the wires together with each wire
twisted round with string or with a strip of ebonite or hard rubber to keep the
wires apart.
In all these cases I apply one or other of the forms of supporting insulating
tubes, insulated and finished as above described.
In all cases I prefer to so construct cables according to my invention that the
air space surrounding the wire may be most definite and may best retain its shape ;
so that the supporting tube enclosing the conductor and the air space may be strong
enough to resist the maximum pressure, may be a good insulator, may not absorb
moisture (or may be so worked that the moisture may be driven off during the
process before the insulation is put on) and may be of the minimum weight, and so
that the insulation is so laid on the supporting tube as to efficiently insulate and
waterproof the cable.
Having now particularly described and ascertained the nature of my said inven-
tion and the best modes known to me of carrying it into effect, I wish it to be
understood that I myself have patented cables formed of paper spirals on a mandrel
and also cables with squirted gutta percha insulation substantially the section set
forth in Figure 10 and I make no claim broadly for such but that what I claim as
new is:
1. The improvement in paper covered cables which consists in forming spirals of
paper with their edges cemented together into a tube on a mandrel with the aid of
a burnisher substantially as described.
2. The improvement in electric cables which consists in the building up of the
insulation in the form of a tube from solid and substantially rectangular, sectioned
or interlocking or mutually sustaining insulating spirals caused to adhere together
substantially as herein described.
3. The various forms of cable built up substantially as herein described and
illustrated.
Dated this 6th day of July 1895.
Dated this 6th day of July 1895.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.