AN IMPROVEMENT IN THE MANUFACTURE OF TELEGRAPH CABLES "
Year: 1878

page_text: LETTERS PATENT to Francis Lambert, of Cornhill, in the City of London, for
the Invention of "AN IMPROVEMENT IN THE MANUFACTURE OF TELEGRAPH
CABLES
"
PROVISIONAL SPECIFICATION left by the said Francis Lambert at the
Office of the Commissioners of Patents on the 23rd February 1878.
FRANCIS LAMBERT, of Cornhill, in the City of London.
THE MANUFACTURE OF TELEGRAPH CABLES."
"AN IMPROVEMENT IN
My Invention relates to an improvement in the manufacture of submarine and
subterranean telegraph cables, having for its object to afford better protection to
the gutta percha, india-rubber, or other insulating material used against the ravages
of the teredo and other animals or insects by which cables are liable to be attacked,
and also for the better preservation of the outer sheathing from the exposure to
the destructive action of the water and constituents of the bottom on which the
cable may rest, or of the earth in which it may be embedded.
My Invention consists in the application and employment as a protective coating
for submarine and subterranean telegraph cables of a layer of the material known as
mineral wool, slag wool, or silicate cotton with a suitable agglutinating material or
composition, if required, such as pitch, tar, oils, collodion, india-rubber, gutta percha,
or other gums or resins, or any suitable combination of these or other substances of
a sufficiently cohesive nature, and capable of resisting the action of moisture.
In carrying out my Invention I may either serve the insulated core with a coating
of this material, or I may first coat or impregnate a tape (or sheet of fabric which
could be afterwards cut up to form a tape) with the compound of mineral wool and
the agglutinating material or composition of materials above mentioned, and lay it
spirally round the insulated core to protect it; or I may first lay a tape round the
core and then apply the protective compound, or instead of using the tape I might
use the silicate cotton alone to form a bed in lieu of the hemp ordinarily used as a
serving for the core; or I may first coat the insulated core or the tape or fabric as

page_text: the case may be with the adhesive material or composition, and then draw it through
or otherwise apply to it the silicate cotton, a thick layer of which is thus caused to
adhere to the core, tape, or fabric.
I may also coat the sheathing externally with a layer of hemp and then apply a
layer of silicate cotton compound or a tape impregnated or coated with such com-
pound as above described.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Francis Lambert in the Great Seal Patent Office on the 23rd August
1878.
FRANCIS LAMBERT, of Cornhill, in the City of London. "AN IMPROVEMENT IN
THE MANUFACTURE OF TELEGRAPH CABLES."
My Invention relates to an improvement in the manufacture of submarine and
subterranean telegraph cables having for its object to afford better protection to the
gutta percha, india-rubber, or other insulating material used against the ravages of
the teredo and other animals or insects by which cables are liable to be attacked,
and also for the better preservation of the outer sheathing from exposure to the
destructive action of the water and constituents of the bottom on which the cables
may rest, or of the earth in which they may be embedded.
My Invention consists in the application and employment as a protective coating
for submarine and subterranean telegraph cables of a layer of the material known as
mineral wool, slag wool, or silicate cotton, with a suitable binding or agglutinating
material or composition, if required, such as pitch, tar, oils, collodion, india-rubber,
gutta percha, or other gums or resins, or any suitable combination of these or other
substances of a sufficiently adhesive nature, and capable of resisting the action of
moisture.
I am aware that precipitated silica or silicate sand has been used in coating
tapes for the protection of cores, and also in compounds for protecting the iron
sheathing of cables, but owing to its coarse nature it is apt to settle in the
compound tank, unless it is constantly stirred, so that it is unequally distributed
through the mixture.
The advantage of the mineral wool is, that owing to its extremely finely divided,
and flocculent state, it remains in suspension in the compound tank, and is distributed
very uniformly throughout the mixture, which is consequently more homogeneous,
and when applied to the cable leaves no vulnerable places.
In carrying out my Invention may either serve the insulated core with a
coating of this mixture or compound of mineral wool and agglutinating material
(hereafter referred to as silicate cotton compound), or I may first coat or im-
pregnate a tape (or sheet of fabric which could be afterwards be cut up to form a
tape with the silicate cotton compound, and lay it spirally round the insulated core;
or I may first lay a tape round the core, and then apply the silicate cotton compound;
or instead of using the tape I might use the silicate cotton alone to form a bed in

page_text: lieu of the hemp ordinarily used as a serving for the core; but preferably I first coat
the insulated core or the tape or fabric, as the case may be, with an adhesive material
or composition (say Stockholm tar and resin) by passing it through a bath thereof,
and then draw it through or otherwise apply to it the silicate cotton, a thick layer
of which adheres to the core, tape, or fabric. After coating the core in this way,
then lay a prepared tape (preferably one impregnated with the silicate cotton
compound) spirally round it to keep the serving of the silicate cotton in place.
I may also coat the sheathing externally with a layer of hemp, and then apply a
layer of silicate cotton compound (mineral pitch and tar being used as the aggluti-
nant in this case); instead of the hemp; one or more tapes prepared in the usual way
to protect them from moisture may be laid spirally on the cable, each tape being
afterwards coated with the silicate cotton compound in the usual way of coating
cables.
The accompanying Drawing illustrates two convenient means of applying the
protective coating of mineral wool, the core being in either case first passed
through the bath of adhesive material, and then through a box or other receptacle
containing the mineral wool, the arrangement being in the one case vertical,
and in the other horizontal.
Figure 1 is a central vertical section of the vertical arrangement.
A is the core drawn off one drum and wound on another, passing over suitable
guide sheaves a, and through the following apparatus. B is an iron tank containing
the bath of adhesive material before referred to, the tank being steam-jacketted to
keep the bath in a sufficiently fluid condition. At the bottom it has a central aper-
ture furnished with a stuffing box b, through which the core A is passed upwards
through the bath B. C is the box containing the mineral wool. It is open at top,
and slightly enlarged in the form of a hopper, to enable the mass of mineral wool to
settle down compactly about the core A which passes up through a central hole cin
the bottom of the box through the mass of mineral wool therein, and then through
a die or gauge D consisting of a tube with a contracted mouth, through which the
core, coated first with adhesive material, and then with mineral wool, is drawn to
remove any excess of mineral wool that may adhere to it. This die D is
supported on cross bars fixed to the box C. E are one or more pairs of pressure
rollers having grooved peripheries which embrace or partially embrace the coated
core, and compress the serving of nineral wool into a uniform and closely adhering
coating.
In the other arrangement, Figure 2, the same letters refer to the same parts as in
Figure 1. In this case the core A is conducted by guide rollers e, through the bath
in tank B, as shown, instead of upwards through the bottom of the same as before,
and thence through an aperture c in the side of the box C containing the mineral
wool which it traverses horizontally, and passes out through a gauge D at the opposite
side, and then through compressing rollers E as before.
Having described the nature of my Invention, and the manner of performing the
same, I declare that what I claim as my Invention to be protected by the herein-
before in part recited Letters Patent is, the application and employment of the
material variously known as mineral wool, slag wool, and silicate cotton, as a pro-
tective coating for telegraph cables, as herein specified.
In witness whereof, I, the said Francis Lambert, have hereunto set my hand
and seal, this Twenty-third day of August, in the year of our Lord One
thousand eight hundred and seventy-eight.
FRANCIS LAMBERT. (L.S.)