Improvements in or relating to Conduits for Electric Conductors.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Conduits for Electric Conductors.
We, FRANK JONES, of 30, Daulby Street, Liverpool, in the County of Lancaster,
Building Material Merchant, and FREDERIC ARTHUR POCKLINGTON, of Freshfield,
mear Liverpool, aforesaid, Electrical Engineer, do hereby declare the nature of
this invention to be as follows:-
This invention is designed to provide an underground conduit for electric
conductors which will be much cheaper that those commonly used hitherto.
"
33
In carrying our invention into effect, we make our conduit in suitable lengths
and wholly of concrete, earthenware or other like insulating material. Each
length is made in the form of a truncated pipe, with flanges at one end adapted
to overlap or embrace the end of the adjacent length, thus constituting an open
duct or channel. By the term truncated pipe' we mean like a pipe with a
part sliced off longitudinally so as to form a segmental circular or elliptical
trough. The trough thus produced is about three fourths of a circle or ellipse
in cross section. The top of the conduit or duct is covered over with tiles or lids
set in cement or mortar. The ducts may if desired be provided at intervals with
transverse pieces or webs, having one, two or more grooves according to the
number of conductors to be placed in each conduit, or in place of these short
beads placed at intervals throughout the length of the duct on which the con-
ductors rest may be employed, or other suitable projection may be provided,
the object in each case being to raise the conductors above the bottom of the
conduit, so as to enable the insulating material which is poured into the con-
duit to entirely surround each conductor and firmly embed it therein. The
diameter or width of the conduit may if desired be greater than the opening
caused by the longitudinal truncating of the flanged ends, and therefore the
conduits when placed together when slipped endways one into the other, cannot
possibly accidentally come apart by any lateral or vertical movement.
In use the conduit is laid in a trench in the ground, and the plain ends of
each length introduced into and embraced by the flanges or socket of the oppo-
site ends of the next adjacent length and a firm joint made, a small countersunk
bolt and nut being used for additional security if desired. In this position they
cannot be accidentally separated because the external diameter or width of the
conduit is greater than the opening resulting in the longitudinal truncating of
the flanged ends. When the necessary number of lengths have thus been
secured together a perfectly clear run for the cables is obtained and both vertical
and horizontal movement of each and every length is absolutely arrested. The

page_text: Suitable
cables are laid in the conduits with distribution boxes placed at intervals as
required and the service boxes at intervals in the branch circuits.
insulating material is poured in, so as to embed the cables in the ducts, the
cables being raised above the bottom of the conduit by the transverse webs,
beads etc. aforesaid. Tiles or lids are then placed on top and are set in cement
so as to form a solid conduit, with the cables firmly embedded inside, and sur-
rounded by the insulating material, the lids pressing the bitumen in the channel
and forming a compact mass. The webs or beads when used, have the effect of
greatly strengthening the conduit as they form transverse ribs which greatly
help to resist fracture.
Each length being comparatively small the whole system is extremely flexible
and easy to adapt to the various requirements of underground main laying
and the somewhat sinuous routes found necessary to avoid obstacles met with
in towns. The absolute rigidity of the conduits after being fixed in position is
a very valuable feature, especially where it is necessary to lay mains in light
loose soil, or in made-up ground such as is frequently met with in all districts.
Should a subsidence of ground take place under the completed main when laid
in these gutters, the latter from their construction are amply strong enough
to withstand any strain to which they may be subjected, and our invention
therefore is immeasurably superior to conduits with butt joints. Should a sub-
sidence take place with the conduits butt-jointed the whole strain of the main
is at once thrown on the cables, whereas with our joint the conduits take all
the strain and fulfil their purpose, which is to support the cables thus avoiding
the defect alluded to.
Earthenware boxes may be provided which interlock with the main at any
position in its length when and where required. These boxes may have the
form of feeder boxes for the insertion of the feeding ends of the mains from
the source of supply and into these boxes distributing mains forming the net-
work are led and connected up by suitable devices, or they may take the form
of network boxes or service boxes; the former for use at the corners of streets
and at other points where a network of distributing mains requires intercon-
necting, the latter being provided for connecting consumers to the neighbour-
ing network. The boxes are so constructed that each tapping cable and its
continuing service cable of one polarity are absolutely separated from the.corre-
sponding pair of opposite polarity, and the risk of short circuiting is entirely
negligable. This is effected by a centre rib of solid earthenware extending
right through and across the box from top to bottom. Should coal or other
gas find its way into the boxes from the surrounding soil there is no possibility
of it being fired by the two conductors sparking across from one to the other.
The boxes may be buried in the ground if access to them is not required or
placed in a chamber or pit fitted with surface covers by means of which easy
and frequent access to the boxes may be obtained. These pits have hitherto
been generally made of brickwork, but by the present invention we propose to
form them of an earthenware chamber sunk into the ground and fitting onto or
over the conduit with a lid on the top. The size of these chambers is such as to
provide ample space round the outside of the boxes for the drainage of surface
water which may find its way between the surface cover or lid and the top of
the pit or chamber. The surface cover may be of iron, stone, asphalt or other
material so as to correspond absolutely with the surrounding pavement, thus
dispensing with the unsightly patches on the pavements that are unavoidable
when substances foreign to the surrounding surface are used.
Dated this 12th day of June 1800
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicants.

page_text: Improvements in or relating to Conduits for Electric Conductors.
We, FRANK JONES, of 30, Daulby Street, Liverpool, in the County of Lancaster,
Building Material Merchant, and FREDERIC ARTHUR POCKLINGTON, of Freshfield,
near Liverpool, aforesaid, Electrical Engineer, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:—
This invention is designed to provide an underground conduit of the open
duct or channel type with interlocking joints for electric conductors which will
be efficient, both mechanically and electrically, and much less costly and more
easily and securely laid than those commonly used hitherto.
In order to facilitate description, reference will be had to the accompanying
drawings, in which,
Figures and are longitudinal and cross sections of the improved conduit:
Figures 2 and 3 are front elevation and horizontal section of a distribution
box showing how branch or distribution conduits are connected:
Figure 4 is a perspective view of a pit chamber to receive the distribution
and house service boxes:
Figures 5, 6 and 7 are vertical cross section, vertical longitudinal section.
and horizontal section showing the conduits connected to a house service box
enclosed in a chamber: and
Figure 8 is a front elevation of the service box and saddle.
In carrying our invention into effect, we make our conduit in suitable lengths
and wholly of concrete, earthenware or other like insulating material. Each
length is made in the form of a truncated pipe A with flanges or sockets a at
one end adapted to overlap or embrace the end of the adjacent length, thus con-
stituting an open duct or channel, as shown in Figures 1 and 1*. By the term
truncated pipe" we mean like a pipe with a part sliced off longitudinally so
as to form a segmental circular or elliptical trough, the trough A thus shaped
being approximately three fourths of a circle or ellipse in cross section. The
top of the conduit or duct is covered over with tiles or lids B set in cement or
mortar. The ducts may if desired be provided at intervals with transverse
pieces or webs, having one, two or more grooves according to the number of
conductors to be placed in each conduit, or in place of these, short beads C
placed at intervals throughout the length of the duct on which the conductors
rest may be employed, or other suitable projection may be provided, the object
in each case 'being to raise the conductors above the bottom of the conduit, so
as to enable the insulating material which is poured into the conduit to entirely
surround each conductor and firmly embed it therein. These webs or beads are
formed in one piece with the conduit but it is obvious that where necessary the
ordinary loose bridges may be used. The diameter or width of the conduit being
greater than that of the opening at the top it follows that a maximum size of
cable may be laid in a given size of conduit, as will be seen from Figure 1".
This feature of the invention is very important from an economical point of
view, and also because the peculiar cross section causes the conduit to interlock
with its contents. Moreover the conduits when placed together and each length
slipped endways into the flanged end of the adjacent length, cannot possibly
accidentally come apart by any lateral or vertical movement.
In use, the conduit A is laid in a trench in the ground, and the plain ends
of each length introduced into and embraced by the flanges or socket a of the
opposite ends of the next adjacent length and a firm joint made, a small counter-.

page_text: sunk bolt and nut being used for additional security if desired, but this is not
usually necessary. In this position they cannot be accidentally separated
because the external diameter or width of the conduit is greater than the open-
ing at the top as before stated. When the necessary number of lengths have
thus been secured together a perfectly clear run for the cables is obtained and
both vertical and horizontal movement of each and every length is absolutely
arrested. The cables are laid in the conduits with distribution boxes such for
instance as E (Figures 2 and 3) placed at intervals as required, and the service
boxes such for instance as F (Figures 5 to 8) at intervals in the branch cir-
cuits. Suitable insulating material is poured in, so as to embed the cables in
the ducts, the cables being raised above the bottom of the conduit by the trans-
verse webs or beads C, etcetera, aforesaid. Tiles or lids B (Figure 1) are then
placed on top and are set in cement so as to form a solid conduit, with the cables
firmly embedded inside, and surrounded by the insulating material, the lids
pressing the bitumen in the channel and forming a compact mass.
The lid or cover B shown in the drawing is of the simplest form consisting of a
tile, but it is obvious that any desired shape may be given to it. For instance it
may be formed with a cambered or rounded or convex upper face which latter
may be of such curvature as to complete the circular or elliptical outer form of
the conduit as a whole. Similarly the undler face of the cover may either be
made straight or more or less concave and may be provided towards the sides
with lugs, shoulders or rebates to engage the edges of the conduit and thus
prevent the cover being displaced sideways, whilst as the lugs or part of the
cover between the rebates will in such case actually enter the conduit a little,
a slight compression of the insulating material will be produced on closing the
conduit. It will also be understood that the upper edges of the conduit instead
of having a horizontal face as shown to receive the cover, may be formed with
a vertical or oblique or radial face or seating for the cover which must have its
edges correspondingly shaped to fit to same. This latter arrangement prevents
lateral displacement of the cover without need of the lugs, shoulders or rebates
aforesaid, By using the lugs or the like, however, the lids or covers may be
made partly self locking by simply shaping the lug or the like at one side of the
cover to hook or catch under the lip or edge of the conduit so as to prevent up-
ward lift at that side, in which case the cover must be put on in such a way
as to let the said edge first engage under the conduit lip or edge before letting
the opposite edge of the cover drop into place.
The webs or beads when used, have the effect of greatly strengthening the
conduit as they may form transverse ribs which greatly help to resist fracture.
The curved form of the conduits in cross section, however, imparts great
strength to them, which renders it usually unnecessary to extend these pro-
jections into the form of strengthening ribs. The beads C shown in the draw-
ings are the best form as affording little contact to the cable and thus ensuring
a good insulation.
Each length being comparatively small, tlie whole system is extremely flexible
and easy to adapt to the various requirements of underground main laying and
the somewhat sinuous routes found necessary to avoid obstacles met with in
lowns. The absolute rigidity of the conduits after being fixed in position is a
very valuable feature, especially where it is necessary to lay mains in light loose
soil, or in made-up ground such as is frequently met with in all districts. Should
a subsidence of ground take place under the completed main when laid in these
gutters, the latter from their construction are amply strong enough to with-
stand any strain to which they may be subjected, and our invention therefore
is immeasurably superior to conduits with butt joints. Should a subsidence
take place with the conduits butt-jointed the whole strain of the main is at
once thrown on the cables, whereas with our joint the conduits take all the
strain and fulfil their purpose, which is to support the cables, thus avoiding the
defect alluded to.

page_text: Earthenware boxes may be provided which interlock with the main at any
position in its length when and where required. These boxes may have the
form of feeder and network boxes such as E (Figures 2 and 3) for the inser-
tion of the feeding ends of the mains from the source of supply and into these
boxes distributing mains forming the network are led and connected up by suit-
able devices, or they may take the form of service boxes F (Figures 5 to 8) the
former for use at the corners of streets and at other points where a network of
distributing mains requires interconnecting, the latter being provided for con-
necting consumers to the neighbouring network.
These distribution and service boxes may be of any desired or suitable kind.
Those shown in the drawings are intended only to illustrate the application of
the invention and they therefore form no part of the present invention except
in that they are provided where required with truncated circular or elliptical
Hanges or sockets a similar to those on the conduits so as to adapt them to
receive the plain ends of the conduits. Similarly where a box is arranged such
as F in Figures 5 to 8 to sit on the main conduit by means of a saddle J, we
form the latter on its under face with flanges shaped to fit over the curved sides
of the conduit to prevent lateral displacement. G is a partition or central rib
of solid earthenware extending right through and across the box from top to
bottom to separate the conductors ay and thus render risk of short circuiting
entirely negligible. Should coal or other gas find its way into the boxes from
the surrounding soil there is no possibility of it being fired by the two conductors
sparking across from one to the other.
The boxes may be buried in the ground if access to them is not required, or
placed in a chamber or pit fitted with surface covers by means of which easy
and frequent access to the boxes may be obtained. These pits have hitherto
been generally made of brickwork, but by the present invention we propose
to form them of an earthenware chamber such as H which may be of any
desired shape made in one piece without a bottom and sunk into the ground
and fitting onto or over the conduit boxes with a lid I on the top. The size of
these chambers H which may be made of other material in cases where greater
strength is desirable is such as to provide ample space round the outside of the
boxes for the drainage of surface water which may find its way between the
surface cover or lid I and the top of the pit or chamber. The surface cover I
may be of iron, stone, asphalt or other material so as to correspond absolutely
with the surrounding pavement, thus dispensing with the unsightly patches on
the pavements that are unavoidable when substances foreign to the surrounding
surface are used.
It will be readily understood that whilst we have described the preferred
form of making the lengths of our improved conduit with one end flanged, such
flange or socket may be dispensed with, and the several conduit lengths be
laid butt-jointed and secured by a loose flange or quasi sleeve of the peculiar
cross section of the conduit, or by any known means adapted to the purpose.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we wish it to be
understood that we are aware that it has been previously proposed to make
conduits for clectric conductors with an internal cross-section of less than three-
quarters of a circle and with transverse projections for supporting the cable,
and we lay no claim to these features of construction, but we declare that what
we claim is: -
•
1. The improvement in conduits of the open duct or channel type for electric
conductors which consists in forming same in lengths with an internal cross
section of not less than three-fourths of a circle or ellipse, whereby a maximum
size of cable may be laid in a given size of conduit and the conduit is caused to
interlock with its contents substantially as herein before set forth.
2. In a system of conduits of the open duct or channel type for electric conductors

page_text: forming one end of cach length of conduit and also desired points of the dis-
tribution and service boxes with flanges or sockets having a cross section of
approximately three-fourths of a circle or ellipse to receive the plain ends of the
correspondingly shaped adjacent lengths so as to form self locking connections
or joints which prevent any vertical as well as lateral displacement of the several
lengths substantially as described.
.
3. Providing the pits for distribution and service boxes of electric conduits
with bottomless chambers made in one piece of desired shape adapted to be sunk
in the ground to fit onto or over the boxes leaving a space round the latter for
drainage, said chambers having surface covers of material preferably correspond-
ing to the surrounding pavement, substantially as described.
4. The improved system of conduits for electric conductors constructed as a
whole substantially as described with reference to the accompanying drawings.
Dated this 26th day of September 1895.
WM. P. THOMPSON & Co.,
Patent Agents, of Liverpool, Manchester, Birmingham & London.