Improvements in the Manufacture of Submarine Cables.
Year: 1894

page_text: Date of Application, 16th Mar., 1894
Complete Specification Left, 17th Dec., 1894-Accepted, 19th Jan., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Submarine Cables.
I, ALEXANDER MUIRHEAD, of No. 2 Princes Street, in the City of Westminster,
Doctor of Science, Electrical Engineer, do hereby declare the nature of this
invention to be as follows :-
One or more layers of tape or the like are wound spirally over a submarine cable
as at present made (whether protected with iron wires or not) as it passes through
a bath of pitchy compound, but such method is very defective in that the tapes do
not permanently adhere to the cable.
My invention has for its object to remedy such defect and to produce a compact
wrapping, which, when cooled, permanently adheres to the cable.
I attain this result by substituting for the closely woven tape hitherto employed
a canvas fabric of open texture, or other substance or material which is reticulated
in character.
The cable as it passes through the bath of pitchy compound is wrapped with a
band of such open or reticulated material or substance through the interstices of
which the pitchy compound covering the cable oozes, gripping the same.
Another
layer of similar, but preferably of less open, material or substance may be wrapped
over the previous layer while the pitchy compound is still fluid or tacky.
The canvas fabric or other substance or material may, previous to use, be
subjected to any suitable process of waterproofing or insulating treatment; the
material or method described in the Specification of Letters Patent No. 8892
dated 9th June 1890 granted to myself and C. R. A. Wright conjointly may be
suitable but I do not limit myself thereto.
The result on the cooling of the pitchy compound is a very compact wrapping
which is firmly combined as a whole by the continuity in the mass of the compound
from beneath the first layer through the interstices thereof and the intermediate
layers to the outside of the cable which then receives its final coating of pitchy
compound.
Dated this 16th dor of March 1901
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Submarine Cables.
I, ALEXANDER MUIRHEAD, of No. 2 Princes Street, in the City of Westminster,
Doctor of Science, 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:-
The usual process of protecting submarine cables which are sheathed or protected
by iron or steel wires is by means of strands or flat bands of hemp saturated with
pitch, asphalt, or other similar materials applied in a hot state round the cable at
the time of its manufacture and this process has been generally adopted up to the
[Price &d

page_text: present time. This has been generally carried out in practice by covering the iron
sheathing of the cable with two layers of closely woven canvas cut into strips
about two inches broad and laid on successively in opposite directions, melted
compound being at the same time poured hot upon the coatings and any excess
scraped off by properly shaped tongs enveloping the cable.
This process has been found to be defective in that sufficient adhesion is not
obtained between the iron wires and the protective sheathing or between the layers
of the sheathing itself and it is frequently found in picking up and repairing, a
cable that the outer protective coating is torn off. This is especially the case after
the cable has been some time submerged, as the canvas coatings, being only
imperfectly saturated with the pitch or like compound, rapidly decay and allow the
whole sheathing to fall or wash off the cable.
To obviate these defects and to produce a compact wrapping which, when cooled,
permanently adheres to the cable is the object of my invention.
According to my invention I employ in place of the ordinary first layer of
closely woven canvas, a ribbon or band of open net-work texture of hemp or other
similar material, with interstices sufficiently large to allow the melted compound to
percolate freely and form a nearly solid continuous mass of compound connecting
and uniting the iron cable through the first layer to the second or outer layer of
canvas. This outer layer may itself be of the open texture such as described.
The said material may, previous to use, be subjected to any suitable process of
waterproofing or insulating treatment. That described in the Specification of Letters
Patent No. 8892 dated 9th June 1890 granted to myself and C. R. A. Wright
conjointly may be suitable but I do not limit myself thereto.
In place of the wet jute serving usually applied next to the gutta-percha core I
prefer to apply a number of coatings or layers of open-textured canvas ribbons
similar to those above described which have been previously thoroughly dried and
saturated in paraffin wax preferably of low melting point or in a compound of
paraffin wax of low melting point with gutta percha as described in the Specification
of Letters Patent No. 5,835 dated 22nd December 1883 granted to me or other
similar material in the manner above described with regard to the sheathing of the
cable, the core so covered being passed through a bath of the same material of
low melting point and any excess scraped off by properly shaped tongs enveloping
the core.
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 ;-
In the manufacture of submarine cables the application of one or more layers of
hemp canvas or similar material of open net-like texture, previously treated as
described, either to the core of such cable, or to its iron sheathing, or to both,
for the purpose of producing a compact and permanently adhering wrapping
substantially as set forth.
Dated this 17th day of December 1804
A. F. SPOONER,
124, Chancery Lane, W.C., Agent for the Applicant.