Improvements in, Laying and insulating Underground Mains for Conveying Electricity
Year: 1889

page_text: Date of Application, 18th Apr, 1889
Complete Specification Left, 19th Sept., 1889-Accepted. 7th Dec.. 1889
PROVISIONAL SPECIFICATION.
Improvements in, Laying and insulating Underground Mains for
Conveying Electricity.
We, WILLIAM HARDING SCOTT Electrical Engineer of Gothic Works King
Street Norwich & LAURENCE PARIS & SCOTT Limited of Gothic Works King, Street
Norwich do hereby declare the nature of this invention to be as follows:
We propose to use for insulating and separating the conductor or conductors,
troughs, blocks, or tubes split or whole of any incombustible and, insulating material
such as earthenware, brick, glass or cement; these enclosing the conductor will be
enclosed in iron or other metal troughs or tubes and the interstices between the
blocks or tubes of incombustible insulating material we should fill in with any
fusible or semi liquid non conductor of electricity such as pitch, tar, resin, parafin
wax or any other suitable fusible or semi liquid non conductor or a suitable mixture
of any of the above substances; so that the spaces between the conductor and the
iron containing troughs or tubes is almost filled in with the non combustible
insulated material which is cheap and indestructible and may be made of con-
siderable thickness the fusible or semifluid insulating material simply filling up and
en a leak occurring melting through the heat produced and probably sealing up the
leak.
We propose to use either cast or wrought iron containing troughs with covers to
the same having flanges which will lap over the sides of the, under troughs a con-
siderable distance; in this case the blocks of incombustible insulating material will.
take the form of thick troughs with one or more grooves or channels for laying the
conductors in; they will be placed in the iron troughs and the conductors in the
channels; the fusible insulating or semifluid insulating material will then be poured.
in to fill up spaces in and between the blocks of incombustible material; this being
done, the covers of the troughs may be put on, the joint being made good in any.
suitable way.
"
In the case where iron containing tubes are used the incombustible pieces will be..
split. in one or more places through the centre of the holes, which are, left for the
conductors, so that they can be inserted in the iron containing tube round the,
conductor or conductors without it being necessary to thread them on the con-
ductors.
When the pieces of incombustible nonconducting material are of a porous nature,
they may be soaked or boiled in pitch or other suitable insulating material, in order
to prevent them ever absorbing moisture, and so impairing the insulation.
In some cases, we propose to use tubes or blocks with holes in them of the..
incombustible materjal, and when extremely high insulation is required two or more..
tubes of glass, porcelain or earthenware or other highly insulating incombustible
material may be made of different diameters so as to slip into one another, the
tubes which will be in short lengths being arranged so as to break joint with one
another.
'
This would be the arrangement with concentric cables or when only one conductor..
was carried in each containing pipe. Where two or more conductors that have to
be insulated from one another, are contained in the same containing pipe or trough,
the incombustible insulating material may be in the form of tubes round each:
conductor with outside blocks having holes in them large enough to take in the
smaller tubes containing the conductor and so arranged that the smaller tubes break..
joint with the larger outside blocks. Other ways of breaking joint may also be
used, such as by conical male and female pieces, or by small connecting sockets;
or tubes let-into suitable recesses or enlargements in the main tubes, and where

page_text: split tubes or blocks are employed, the longitudinal joint may be broken by having
inside and outside tubes or blocks.
It is proposed in every case to fill in the interstices between pieces of incombus-
tible insulating material by means of any suitable insulating fusible or semifluid
substances as before mentioned.
This fusible or semifluid insulating material may be forced under pressure into
the containing tubes or troughs after they are laid, in such a way that the air is
driven out before it, and the pressure may be kept up until the whole is quite cool
80 that contraction may not cause holes and spaces to be left, and in the case where
iron. containing troughs with lids are used, the fusible or semifluid material may
be filled up above the top of the trough, being prevented from running over by light
and unsubstantial ridges or walls of thick paper or cardboard or other suitable
material so that on the cover being placed on, any weight placed on this cover will
come on the fusible or semifluid material, thus forcing it into the joints of the
trough and its cover, and allowing contraction to take place without hollow spaces
being formed.
Dated this 16th day of April 1880
WILLIAM HARDING SCOTT.
REGINALD LAURENCE, }
W. H. SCOTT,
Directors.
Arthur F. Armstrong, Secretary.
COMPLETE SPECIFICATION.
Improve.nents in Laying and Insulating Underground Mains for
Conveying Electricity.
We WILLIAM HARDING SCOTT Electrical Engineer and LAURENCE PARIS and
SCOTT Limited Engineers both of Gothic Works Norwich in the County of Norfolk
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:
.
According to this Invention we use for insulating and separating the conductor
or conductors of underground lines or mains for conveying electricity troughs
blocks or tubes split or whole and of any suitable incombustible and insulating
material such as carthenware, brick glass or cement or combinations of them these
being placed end to end so as to form a continuous line and enclosing or containing
the conductor or conductors throughout its or their entire length and themselves being
enclosed in troughs or tubes of iron, wood creosoted or not or other strong material.
The interstices between the blocks or the like of incombustible and insulating
material and their containers we fill in with any fusible or semi-liquid nonconductor
of electricity which is waterproof such as pitch, tar, resin, resin oil, paraffin wax or
mixtures of them or any other suitable fusible or semi-liquid nonconductor having
the-same or like properties. We prefer to use a mixture of the said substances
which at normal temperature is so solid or nearly solid that it will not run away
through a small crack in the containing troughs or tubes but will run together and
seal up any crack or fracture which may occur inside the troughs or tubes or in
the troughs or tubes themselves. A cheap and convenient composition for the
purpose may be made by melting pitch or resin with from 5 to 20 per cent. of tallow,
paraffin wax or resin oil. The space between the conductors and the containing
troughs or tubes is filled in or almost filled in with the noncombustible and insulated
material which is cheap and practically indestructible and may be made of con-
siderable thickness the fusible or semifluid insulating material simply filling up
the small spaces left and preventing any moisture getting to the conductors. Should
however a leak occur the material will melt through the heat produced by the
current and in all or many cases will seal up the leak.
Figure 1 of the accompanying drawing represents in cross section (on the line
3-4 Figure 2) and Figure 2 in longitudinal section (on the line 1-2 Figure 1) an

page_text: arrangement according to this Invention. We preferably use either cast or wrought
iron for the containing troughs A. and to provide them with covers a having flanges
which lap over the sides of the troughs A. a considerable distance. The blocks
of incombustible and insulating material are in the form of thick troughs B with
one or more grooves or channels as at b. These trough like blocks B are placed in
the troughs A. end to end so as to form a continuous line and the conductors C
are laid in the channels b.
The fusible insulating material d will then be poured in while quite hot and fluid
so as to run into and fill up all the interstices left between the blocks or troughs of
insulating material, the conductors and the outside containing troughs so that when
the covers a are put on and secured together by the junction pieces D D¹ (which are
placed at the joints between the troughs and over lap each pair of adjacent ends of.
the troughs the whole forms a well insulated electric main which is protected from
mechanical external injury by the containing trough or tube. The said main is
also impervious to moisture of any kind even should the outside containing trough
or tube be imperfect or damaged such for instance as might be caused by a blow
from a pick.
Moreover the conductor is supported along its whole length by hard solid supports
that are insulating incombustible and practically indestructible and so cheap that
they may be used of considerable thickness.
Figures 4 and 5 show the containing troughs with a cover a having projections a³
which fit over and make a good joint with the engaging edges a of the under troughs
so that the fusible or semi-fluid material shall make good or help to make good the
joint between the bottom trough and the,cover. Hemp rope canvas or asbestos
or the like may be added to assist in making the joints.
'
The junction pieces and covers D D₁ serve to clamp the covers a down on to the
troughs A. but they can be narrower if required than in the case of Figures 1. 2
and 3.
The troughs and covers may be made in any convenient way or we may use tubes
of iron or other suitable metal or strong material and in this case the incombustible
and nonconducting blocks B are split in one or more places through the centre of
the recesses therein for the conductors so that they can be inserted in the said tubes
round the conductors without it being necessary to thread them on the conductors.
In ordinary cases we prefer to use ordinary terra cotta bricks or earthenware for
the pieces of incombustible and nonconducting material and when they are of a
porous nature they may be soaked or boiled in pitch or other suitable insulating
material in order to prevent them from absorbing moisture and so impairing the
insulation.
We have shewn in Figures 1 and 2 plates or lengths of glass, porcelain or other
incombustible nonconductor e placed around the conductors and Figure 3 shows an
arrangement like Figure 1 but wherein glass or other nonconductor e
is placed
above the conductors and between the two series of them contained in the recesses b
but these may be omitted from both arrangements. The parts in Figures 2 and 3
which correspond with those shewn in Figure 1 are marked with the same letters of
reference.
In some cases we propose to use tubes or blocks with holes in them and made of
the incombustible and nonconducting material and when extremely high insulation
is required two or more tubes of glass porcelain earthenware or other highly
insulating incombustible material may be made of different diameters so as to
slip into one another the tubes which will be in short lengths being arranged so
as to break joint with one another. This arrangement is shown in cross section
in Figure 6 and in longitudinal section in Figure 7 where the conducting cable is
marked C and the tubes of incombustible and insulating or non conducting material
are marked B the way in which their junctions break joint being clearly shewn in
Figure 7. A is the containing tube of iron or other strong material and d the
semi solid or solid fusible non conducting and waterproof insulating material run
into the spaces as in the previous cases.

page_text: This is the arrangement with concentric cables or when only one cable is carried
in each containing pipe. Where two or more cables are used and have to be
insulated from one another being contained in the same containing pipe or trough
as shewn in Figures 8, 9 and 10, Figure 8 being in cross section and Figures 9 and
10 longitudinal sections taken respectively on the lines 5, 6 and 7, 8 of Figure 8 the
incombustible and insulating material is in the form of a tube or tubes B³ round
each conductor with outside blocks 13 having holes in them large enough to take in
the smaller tubes 133 and so arranged that the tubes B³ break joint with the joints or
meeting ends of the blocks B*. The spaces are filled in with the semi-solid or solid
and fusible waterproof and insulating material as in the preceding cases Other
ways of breaking joint may also be used such as by conical male and female pieces
or by small connecting sockets or tubes let into suitable recesses or enlargements in
the main tubes and where split tubes or blocks are employed the longitudinal joint
may be broken by having inside and outside tubes or blocks.
This fusible or semi fluid insulating material may be forced under pressure into
the containing tubes or troughs after they are laid in such a way that the air is
driven out before it and the pressure may be kept up until the whole is quite cocl
so that contraction may not cause holes and spaces to be left and in the case where
iron containing troughs with lids are used the fusible or semi-fluid material may
at the junctions be piled up above the top of the trough being prevented from
running over by light and unsubstantial ridges or walls of thick paper or cardboard
or other, suitable material so that on the junction pieces being placed on, any
weight brought to bear thereon will come on the fusible or semi-fluid material,
thus forcing it into the joints of the trough and its cover and allowing contraction
to take place without hollow spaces being formed.
In Figure 11 we shew a section of a main in which the outside containing trough
is made of wood which we prefer to have creosoted or otherwise made more durable.
The three pieces marked A are first put together and fastened by nails screws or
any other convenient way. We prefer to make up the trough out of the three pieces
of wood in position, the different lengths being made to finish off in different places
so that a continuous trough is formed, when the troughs B the conductors and the
filling in pieces are in position, the insulating material is poured in hot and the
trough is filled up a little higher than is shown in the drawing the lid (a) is then put
in position and weighted by which means not only is the hot insulating material
forced into all the interstices but the lid a follows it as it contracts in cooling and
no empty spaces are formed, when the whole is thoroughly cold the lid is nailed or
otherwise fastened down.
This procedure of course has to be modified to suit circumstances as for instance
on a slope but in all cases the lid must be allowed to follow the contracting material
and be fastened afterwards.
By our invention great strength and protection is given together with sufficient
flexibility to stand ordinary settlements and damages to which roadways are sub-
ject, no moisture can get to the conductors even though the containing trough be
cracked or damaged to a considerable extent. The conductors which do not require
to be otherwise insulated are supported along their whole length and require no
straining and the substance that supports it is not affected by heat, it is very cheap
and can be made of considerable thickness.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed, we declare that what we
claim is;
1. The laying and insulating of underground mains for carrying electricity by
the means substantially as herein before described and illustrated in the several
Figures of the accompanying drawings.
2. For laying and insulating underground mains for carrying electricity troughs
or boxes of metal or other strong material formed as described and containing
bricks or blocks of insulating and incombustible material grooved for containing

page_text: the conductors so that they can be laid in the said grooves the spaces between the
said bricks or blocks and metal (or the like) outer box being filled with an insulating
fusible and waterproof medium substantially as and for the purposes described and
as illustrated in the accompanying drawings whether the junction pieces be used
therewith or not.
3. In laying and insulating underground mains the introduction into the spaces
between the conductor and envelopes of semi-fluid or liquified insulating material,
which is maintained under artificial pressure until cold or sufficiently cooled sub-
stantially as and for the purposes herein before described. Also the method of
filling in the said material above the top of the trough before placing on the
junction pieces substantially as described."
1011
A
1000