Improvements in Laying and Insulating Underground Wires Intended for Use as Conductors of Electricity.
Year: 1887

page_text: Improvements in Laying and Insulating Underground Wires
Intended for Use as Conductors of Electricity.
1 THOMAS OCTAVIUS CALLENDER of 101 Leadenhall Street in the City of London
Merchant do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved method of laying and insulating underground
Wires used as clectrical conductors for the purposes of telegraphic or telephonic
communication so as to be suitable for rapid telegraphy and for the use thereon of
multiplex telegraph instruments.
It is well known that the use of multiplex telegraph instruments is rendered
difficult on underground lines owing among other causes to the fact that the inductive
capacity of the conductors when insulated and placed underground in pipes in the
usual way is much greater than that of bare overhead wires. It is known that this
increased inductive capacity can be reduced by employing an increased thickness
the sheathing of insulating material, and the difficulties of rapid working can also as
is known be reduced by increase in the area of the conductor which should however
be covered with insulating material in a ratio proportionate to its diameter.
The largely increased quantity of material necessary to effect either or both these
purposes with Gutta percha or India-rubber the materials now in general use for
underground telegraph lines would render the cost of so doing prohibitive.
The object of this invention is to reduce the inductive capacity of any underground
conductor and at the same time by the employment of a method of laying and
insulating the conducting wires to attain the desired result with efficiency and also
economically.
My improved method of laying and insulating wires used as electric conductors is
carried into effect in the following way: a case or trough of the dimensions required
which I find may be advantageously formed rectangular in shape is made of bitumen
concrete in the required lengths. Such lengths are carefully jointed together "in
situ so as to form one continuous case or receptacle for the conductors, these
"3
"

page_text: conductors are each first insulated preferably with the bituminous material described
in the specification of Callender's Patent dated October 11th 1881, No. 4409, and are
protected in the usual manner by tape braiding or otherwise.
When desired they can be stranded into cable form or covered in groups by the
usual machinery.
As many of such conductors whether single or in cable form as are required are
laid in the case or trough with a space more or less between each being held in
position by spacing bridges placed in the case or trough at suitable distances. The
whole vacant space is then filled by running in refined bitumen in a molton state care
being taken that it is not of too high a temperature to char burn or otherwise injure
the insulator on the cables or wires and also that no vacant space is left either between
the individual conductors or between such conductors or cables and the case or
trough. By employing the trough or casing with the wires laid and embedded in the
manner above described and employing the materials above mentioned groups or
systems of underground wires can be laid more efficiently and cheaply than by any
method hitherto adopted.

page_text: Intended for Use as Conductors of Electricity.
I THOMAS OCTAVIUS CALLENDER of 101 Leadenhall Street in the City of London
Merchant 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 Invention relates to an improved method of laying and insulating underground
wires used as Electrical Conductors for the purposes of telegraphic or telephonic
communication so as to be suitable for rapid telegraphy and for the use thereon of
multiplex telegraph Instruments.
It is well known that the use of multiplex telegraph Instruments is rendered
difficult on underground lines owing among other causes to the fact that the inductive
capacity of the conductors when insulated and placed underground in pipes in the
usual way is much greater than that of bare overhead wires. It is known that this
increased inductive capacity can be reduced by employing an increased thickness of
the sheathing of insulating material and the difficulties of rapid working can also as
is known be reduced by increase in the area of the conductor which should however
be covered with insulating material in a ratio proportionate to its diameter. The
largely increased quantity of material necessary to effect either or both these purposes
with gutta percha or india rubber the materials now in general use for underground
telegraph lines would render the cost of so doing prohibitive.
The object of this invention is to reduce the inductive capacity of any underground
conductor and at the same time by the employment of a method of laying and
insulating the conducting wires to attain the desired result with efficiency and also
economically.
My improved method of laying and insulating wires used as electric conductors is
carried into effect in the following way. A case or trough of the dimensions required
which I find may be advantageously formed rectangular in shape is made of bitumen
concrete in the required lengths. Such lengths are carefully jointed together
"in situ " so as to form one continuous case or receptacle for the conductors. These
conductors are each first insulated preferably with the bituminous material described
in the Specification of Callender's Patent dated October 11th 1881 No. 4409 and may
be protected in the usual manner by tape braiding or otherwise.
When desired they can be stranded into cable form or covered in groups by the
usual machinery.
As many of such Conductors whether single or in cable form as are required are
laid in the case or trough with a space more or less between each being held in
position by spacing bridges placed in the case or trough at suitable distances. The
whole vacant space is then filled by running in refined bitumen in a molten state care
being taken that it is not of too high a temperature to char burn or otherwise injure

page_text: the insulator on the cables or wires. And also that no vacant space is left either
between the individual conductors or between such conductors or cables and the case
or trough. By employing the trough or casing with the wires laid and embedded in
the manner above described and employing the materials above mentioned groups or
systems of underground wires can be laid more efficiently and cheaply than by any
method hitherto adopted.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I do not limit myself to the exact
form of the case or trough above described but I declare that what I claim is―
1. The method of reducing the static or inductive capacity of insulated wires used
as Electric Conductors by laying them in cases troughs or receptacles substantially as
above described.