IMPROVEMENTS IN AND RELATING TO INSULATED WIRES AND CABLES, AND IN THE METHODS OF INSULATING, FIXING, AND LAYING THE SAME FOR TELEGRAPHIC AND OTHER PURPOSES
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Walker Moseley at the Office of the
Commissioners of Patents on the 24th January 1879.
WALKER MOSELEY, of Liverpool, in the County of Lancaster.
"IMPROVEMENTS
IN AND RELATING TO INSULATED WIRES AND CABLES, AND IN THE METHODS OF
INSULATING, FIXING, AND LAYING THE SAME FOR TELEGRAPHIC AND OTHER
PURPOSES."
',
The object of this Invention is to obtain more perfect and permanent insulation
in electric conductors to facilitate their being fixed or laid in position, and in many
cases to reduce their expense. Up to the present time it is found that insulated
wire fixed on land, whether the insulator be gutta percha, indiarubber, or any non-
conducting compound, becomes so much deteriorated by various atmospheric changes
and pollution that the defects in the nonconducting substance expose the wire to
the effects of dampness, in which case the electric current, whenever it meets with a.
"return" (whether by "earth or otherwise) acts through the water to the disso-
lution of the wire until complete rupture takes place. In the case of submarine
cables it is found that gutta percha loses its virtue as an insulator, and contracts
during the process, whilst india rubber does so by increasing in bulk through. its
absorption of water; submarine insects are also found to attach and penetrate the
gutta percha. The various compounds that have been tried have also failed to
retain their insulating properties. The materials hitherto adopted to insulate the
conducting wires offering very little resistance to pressure or tension have required
great support and protection, which has been generally effected by surrounding the
core with tape, fibre, iron, and steel wire, et cetera. This has led to the adoption of
cables of bulky construction without effecting sufficient protection. It is found
that comparatively light cables are quite as effective and durable as the heavier.
ones.
My oxperience of all the pliable non conductors is that they will not resist the
action of air and water, but since adopting the method described in my Patent,
No. 2926, 1873, for the protection of the positive wire in electric plant, I have
found that the insulation remains quite perfect in ships fitted five years ago. I
have now devised means for obtaining the same object in relation to "line" wires.
I am aware that the protection of insulated wires by metal and other tubes, et cetera,
is old, but my Invention is designed to overcome all the difficulties and objections
that have attended every attempt to adopt them. In my Invention I abandon the
idea that the insulating material must necessarily be waterproof. Any fibre that
has good strength and good insulating properties will answer the purpose, but I
Davina 71

page_text: prefer horsehair as having the best combination of desirable properties, viz., a perfect
insulator, great tensile strength, very unyielding to any blow or pressure, very
pliable, and strong elasticity. I propose to surround the wire or cable with twisted
strands of this material, then to saturate the whole with melted resin or gum with
a little oil to toughen it. I then enclose it in a double sheathing of copper or other
metal, with tin or composition between the double sheath, but the melting point of
the soldering metal must not be so great as to injure the hair. The method I
propose to adopt, which is one part.of my Invention, is as follows: The size of
copper conductor being given, and the thickness of the insulation being determined,
I procure sufficient lengths of copper tape of such width as will envelope the
circumference. I then tin both sides by passing the whole through molten tin in
a bath provided with a wiper at each end, the one at its entrance being supplied
with powdered resin, and the one at the exit to wipe off all surplus metal adhering.
I provide also equal lengths of tin tape, or a softer metal alloy if desired, and another
series of copper tape of three thicknesses, wider than the other copper tape. I then
proceed to pass the insulated wire along with the first tape through hollow edged
rollers, thus folding the tape longitudinally round the covered wire. I then apply
the tin tape in the same way, with the joint reversed to the opposite side. I then
apply the second copper tape in the same way and at the same time. I follow this
operation by causing the triple tape covered wire to pass through a block of iron,
with the hole wider at the entrance than at the exit, a thermometer being inserted
in a hole made for the purpose; the block of iron will be kept heated to about 450°.
As the covered wire is drawn through this block the two copper tapes will be
soldered together, forming a solid metal sheath of equal thickness all round.
If the average supply of horsehair should be found to suffer any injury when
subjected to a heat of 450°, it will be desirable to alloy the tin with bismuth, but
my experiments indicate that pure tin in a molten state deteriorates neither the
the elasticity nor tensile strength of horsehair.
For submarine cables I may corrugate the metal sheathing with annular corru-
gations for the purpose of making it more pliable, but I do not consider this necessary.
I may also cover the metal sheathed cable with strands of fibre and wire, but I
doubt its desirability except for the shore ends.
By this method, as briefly described, I obtain perfect insulation and strength for
telephone conductors and like purposes by using about one pound weight of hair to
thirty yards of wire, and for submarine cables about one pound of hair to three
yards of wire.
I may also employ other fibre in combination with the hair. In order to relieve
these light cables more effectually from any sudden strain from the ship rising
suddenly in rough water I propose to cradle a pulley at the end of a long arm, say,
twenty feet long, the said arm to be counterbalanced so that an extra strain of, say,
2 hundredweight, is needed to pull it over. The cable being made to pass over
this pulley at the end of the arm which in its normal position shall be upright, and
thence over a pulley at the ship's bows, it will follow that a sudden rise of the ship
will overtake the speed of the paying out machinery, and the long arm will be
pulled over; the paying out machine will then be accelerated either by the automatic
action of a spur at the bottom of the long arm gearing into the machine, or else by
a man constantly standing by.