IMPROVEMENTS IN UNDERGROUND CONDUITS FOR ELECTRIC WIRES AND IN THE METHOD OF Laying the WIRES THEREIN A
Year: 1882

page_text: ETTERS PATENT to Alfred Julius Boult of the firm of W. P. Thompson
& Boult, Agents for Foreign Patent Solicitors, of 323 High Holborn, London
in the County of Middlesex and Lord Street, Liverpool, in the County of
Lancaster for an invention of "IMPROVEMENTS IN UNDERGROUND CONDUITS
FOR ELECTRIC WIRES AND IN THE METHOD OF Laying the WIRES THEREIN
A communication from abroad by Joseph Drew Thomas, of the City, County
and State of New York, United States of America
"
PROVISIONAL SPECIFICATION left by the said Alfred Julius Boult at the
Office of the Commissioners of Patents on the 5th April 1882.
ALFRED JULIUS BOULT of the firm of W. P. Thompson & Boult, Agents for
Foreign Patent Solicitors, of 323 High Holborn, London, in the County of
Middlesex, and 6 Lord Street, Liverpool in the County of Lancaster, "IMPROVE-
MENTS IN UNDERGROUND CONDUITS FOR ELECTRIC WIRES AND IN THE METHOD
"
OF LAYING THE WIRES THEREIN [A communication from abroad by Joseph
Drew Thomas, of the City, County and State of New York, United States of
America.]
This invention relates to improved means for, and a method of, protecting
electrical wires that have to be laid underground,
According to this invention electrical wires, such as used for the purposes of
telegraphy and for telephonic and electric lighting apparatus, are placed into a
conduit of special construction and are preferably embedded in the material
hereinafter named. In the said conduit provision is made for ready access to the
wires and for readily "tapping" and repairing the same.
The conduit according to this invention is constructed as follows, The base or
bottom part consists of troughs or shallow boxes by preference made of glazed
earthenware; at their open ends these troughs are provided with lips or flanges so
that each one can overlap the one adjoining it at one side whilst its other end
extends under the lip or flange of the contiguous trough. If desired one or more
Price C21

page_text: division walls may be provided in these troughs for a purpose that will hereinafter
appear. The outer edges or walls of the said troughs are rabbetted so as to make a
better joint with the lids hereinafter described.
The division walls above mentioned serve to form two or more separate channels
in one conduit as for instance where telegraphic and telephonic lines are to be laid
in one conduit and yet are to be kept separate.
•
The said division walls are' of the same height as the sides or outer edges of
the trough so that the lid when in position will rest on the edges of the trough and
also on the division walls.
The lids for these troughs are likewise preferably made of glazed pottery ware
and form shallow inverted boxes; they have however no division walls and their
edges are plain and fit upon the rabbets of the base troughs. Their ends open like
those of the above described troughs are similarly constructed with a view to
causing adjoining lids to overlap one another. The rim of the lids has small
apertures into which a lever or crow bar can be inserted to allow the same to be
prized open when required after the conduit has been laid down
In laying down a line the base troughs are first laid and their over-lapping
edges united by hydraulic cement, the wires are then put into place and it will be
found very advantageous to embed the same in soapstone or the like and they will
be moreover insulated in the usual manner so as to prevent electrical contact
between the individual wires. The lids are subsequently laid over the troughs so
as to "break joint" with the same as will be readily understood and the lids are
joined, both with the troughs and with one another, by hydraulic cement. The
wires may be laid down in the troughs in any convenient manner, for instance
they may be wound upon a drum resting on a small vehicle and the vehicle
may be drawn along so as to unwind the wires in proportion as they are covered
by the lids.
Where it is required to "tap" the wires suitable tubular extensions project
from the lids and are covered by a cap secured by cement as above described
or the cap may directly cover an aperture in the lid and an insulated wire pass
through.
At suitable distances apart stations are provided for facilitating the inspection
and repair of the wires and at such stations the ordinary electric apparatus such
as telegraphic or telephonic apparatus or dynamo machines, may also be placed
When a wire becomes defective, it may be cut and a line be attached to one of the
cut ends; by hauling in the part thus cut, say at the next station, all defects
may be remedied and the line attached to the wire will afford a ready means for
bringing the end of the repaired wire, or of a new one inserted therefor, to the
place where the connection has been cut and the circuit may thus be re-
established.
A convenient way of uniting the ends of wires is to provide them with screw-
couplings and to cover the said couplings with insulating material (say India
Rubber) in the same manner as the wires. Each wire may have suitable India
Rubber or other labels attached thereto so as to prevent mistakes in "tapping"
and repairing the various lines.
Although the troughs and lids which form the conduit are hereinabove described
as being made of glazed pottery-ware and united by hydraulic cement and although
such material is particularly adapted to such purpose, it will nevertheless be
understood that the conduit may be made of metal or other material if desired;
the tubular extensions and the particular lids to which they are attached may well
be made of iron.
The outer edges of the lids and of the base troughs may be bevelled off so as to
allow the same to be more readily embedded

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alfred Julius Boult in the Great Seal Patent Office on the
5th October 1882.
ALFRED JULIUS BOULT of the firm of W. P. Thompson and Boult Agents for
Foreign Patent Solicitors, of 323 High Holborn, London in the county of
Middlesex, and 6 Lord Street, Liverpool in the County of Lancaster IMPROVE-
"
MENTS IN UNDERGROUND CONDUITS FOR ELECTRIC WIRES, AND IN THE METHOD
»
OF LAYING THE WIRES THEREIN, A communication from abroad by Joseph
Drew Thomas of the City and State of New York, United States of America.
Numerous methods of laying electrical wires in underground tubes or conduits
in lieu of the overhead system now in use have heen heretofore proposed, but I am
not aware that any method has been yet devised which so perfectly fulfills the
several practical requirements as would commend it to the general adoption of
telegraph or other electrical companies in place of the present system.
For the purpose of an underground wire conduit it is quite important that the
structure be comparatively cheap in first cost, both as to material and the manner
of its construction and also that it be durable to underground influences and while
perfectly enclosing and protecting the wires will yet admit of ready access to the
wires at any part of the lines when required for the purpose of making connections,
of examining the wires or inserting or removing portions thereof. I have therefore
aimed to devise a conduit which will embody these important advantages and to
this end I construct my improved wire conduit of baked pottery clay or equivalent
earthen ware which is formed in hollow longitudinal sections laid end to end and
secured together to form a continuous conduit, by portland cement or other means
thus securing a material of construction which is very cheap and very cheaply laid
and moreover is absolutely proof to all underground influences and while
possessing great strength to resist underground strains, it is yet of that nature
which admits of being easily bored cut or broken into at any part to give easy
access to the wires wherever desired and can afterwards be as readily repaired.
Furthermore each longitudinal section of my improved conduit is itself bisected in
two vertical halves or sections, that is, an underlying trough shaped section, which
receives the wires, and an overlying lid or cover cemented over the former to
completely enclose the wires, by which construction the conduit is very easily laid
and the lid of any section can at any time be easily broken off or removed, if
required to get at the wires and a new lid afterwards put in its place with little
cost. The meeting ends of each section are also so flanged or rabetted and the
two halves of each section so relatively placed that the ends lap in such manner
as to produce very secure joints and the several features here outlined together
with a number of features constitute the essence of my invention as hereinafter
fully set forth.
In the annexed drawings Figure 1 presents a perspective view of one section of
my improved wire conduit Figure 2 represents a cross section of a street showing
a longitudinal elevation of my improved conduit which is laid under the same.
Figure 3 is an enlarged cross section of the conduit with the wires laid therein.
Figure 4 represents one manner in which a station may be formed in the line of
the conduit, or one manner in which the conduit may be tapped.
On reference to Figure 1 it will be readily seen that each section of the conduit
is made in two vertical divisions or parts ab one fitting over the other, The lower
part or receptacle a is of a trough shape to receive the wires as illustrated and its
opposite sides or edges are formed with the marginal lips c and shoulders d. At

page_text: about the middle of the trough two dividing webs e e arise from the base of the
trough to a level with the lips or edges c and run the whole length of the trough
parallel with its sides so as to divide it into three parallel compartments f g h
adapted say for telegraph, telephone, electric light wires respectively, thus providing
a distinct cell or duct for each distinct kind of service. These dividing webs may
however be omitted altogether, or more or less than the two shown may be used,
as circumstances demand as will be understood.
The upper section or cover b is formed with a flat or level underside which rests
upon the edges c c of the trough and its dividing webs ee and also has pendant
marginal edges or lips i which overlap the lips c of the trough and rest upon the
shoulders & as shown the sides of the trough and cover being of course flush with
each other when the two are placed together as illustrated in Figures 1 and 3.
The longitudinal corners on the bottom of the trough and on the top of the lid are
beveled off as shown at k so that the structure will embed itself better in the
ground and be lighter and of a better shape for forming and handling as will be
appreciated
The ends of both the trough and lid do not terminate abruptly but are recessed
or rabetted uniformly across the ends so as to form an underlying ledge at one
end of each part and overlying ledge m at the opposite end of the same so that
when the sections are laid end to end as seen in Figure 2 to form the continuous
conduit these ledges overlap and thus break joints in a very simple and secure
manner which is favourable to strength and to the exclusion of moisture. I also
prefer as shown best in Figure 2 to so lay the upper and lower divisions of the
conduit relatively to each other that the ends of the upper divisions meet at the
middle of the lower divisions or nearly so and vice versa which also conduces
greatly to the strength and tightness as will be appreciated.
As before noted I prefer to construct both the troughs a and lids 6 in the form
already described and shown of commom pottery clay or equivalent earthen
material which is pressed or moulded in the described shape in the same manner as
is employed in the manufacture of bricks tiles, drain pipe or terra cotta work and
afterwards baked and glazed. By this means not only is the first cost of the
conduit rendered very cheap comparatively but its material is absolutely durable
under ground, is proof to moisture and is comparatively light and may be easily
handled and laid rapidly by a small number of men I prefer to make the lid and
trough of each section of such a size as seen in Figure 1 that they may be easily
lifted and handled by one man and I prefer to make the thickness of lid and
trough equal to that of a common brick thus securing necessary strength with
comparative lightness. Instead however of making the lid and trough of a solid
thickness as seen in Figure 1 the outer sides may be panelled or recessed if desired
to reduce the weight of material and offer greater surface for embedding in the
ground if desired, but I prefer the solid form.
It may now be understood that to lay the improved conduit it is only necessary
to first dig a trench to the desired depth and of the correct size and proper grade,
after which the trough sections a a are placed in the trench one after the other
and fitted together at the ends, the ledges overlapping each other as shown and
joined securely by a thin film of portland cement placed between them which
rapidly sets and soon joins the sections firmly together. In this way the conduit
may be laid with rapidity by say three men, one in the trench to lay the sections,
one on the bank to hand the sections to the former and a third to keep the others
supplied with materials. When a sufficient length of the trough or lower part of
the conduit is laid, say one mile section thereof, the wires can then be placed
therein and the covers bb afterwards placed over the same these covers being fitted
end to end, same as the troughs and fitted over the edges of the trough, as before
described, a thin film of portland cement being used to joint the meeting surfaces
by which the whole work becomes completed in a very rapid simple and secure
manner. Instead of laying a great length of the trough before putting in the
wires and putting on the covers, the wires may be laid in the troughs and covered

page_text: in as fast as the troughs are laid or as fast as the cement on the recently laid troughs
set if preferred for in this case the wires may be wound on a drum and mounted on
a small car which can be run along upon the lips c of the trough as upon a railway
so as to thereby deposit the wires in the troughs as fast as the troughs are laid and
in a very easy and simple manner and the lids may then be cemented on the trough
as fast as the wire car advances.
The wires it is presumed will be properly protected or insulated so that a
number may be laid closely together in the compartments of the conduit as seen in
Figure 3 without making electrical contact with each other. For this purpose
I prefer to cover the wire uniformly with a thick coating of rubber which ensures
perfect protection which coating I have described in a separate application filed
March 18th 1882, but of course any suitable method of insulation may be employed.
It is presumed that the wires will be furnished in certain lengths say of one or
more miles and at the end of each section of wire the conduit may open into an
underground station house as seen in Figure 4 where the wires may be coupled
together or connections made therefrom with switch boards, telegraph offices,
dynamo machines or other arrangements according to circumstances or the nature
of the service in which the wires are employed. At certain intervals along the
length of the conduit however a lid b' will be introduced between the plain lids
having an elbow or large nipple or manhole n projecting therefrom preferably at
an easy inclination which will be ordinarily covered with a cap s cemented thereto,
but which can be easily removed when it is desired to tap any wire within the
conduit or lead a connection therefrom to a station, office or dwelling along
the line of the conduit. Thus as shown in Figure 1 from the elbow on the
conduit under one street corner an earthen pipe is led to the base of a hollow
ornamental column t which rises from the sidewalk and through this pipe and
column the wires may be led from the conduit as shown some of which may extend
into the building opposite to connect with telegraphs, telephones, or electric lights,
while another wire connected with the fire alarm service may extend to a fire
signal instrument in a box on the column as will be readily understood. At the
opposite street corner a well protected wire passing simply through the ground into
the building may be led through a hole bored into the cover of the next elbow and
connected with the appropriate wire within the conduit as will be understood thus
enabling connections to be made in various ways and in a very simple manner,
The wires may be coupled together at the ends of each section by screw coupling
sleeves screwed onto the threaded ends of the wires and these couplings may be
afterwards covered and insulated by a sleeve of rubber so as to completely enclose
the coupling and present an exterior uniform with the rubber covering of the wire.
The wires may also be labeled at or on the couplings to indicate their individuality
by india rubber labels cemented to the rubber covering so that any particular wire
may be readily identified when access is had to the station box on the conduit
where the sections of wires will usually be coupled together.
It may now be seen that if it is desired at any time to remove any wire or
section thereof it can be readily done by drawing the desired wire out at any
station house or tapping section by means of a small windlass (see Figure 4) the
wire being of course previously cut at the next distant station a tow line attached
thereto and thus drawn through-the conduit. A new wire can thus be attached to
the tow line and drawn back to the distant station, after which the cut ends of the
wire may be coupled, thus replacing a damaged section of wire by a new section in
a simple and certain manner. In order to enable a wire to be thus easily drawn
in or out of the conduit between the other wires, I prefer to embed the whole series
of wires in the conduit, as seen in Figure 3, in a mass of powdered soap-stone or
other lubricating powder, preferably a nou conductor, which will serve to lubricate
the motion of the wire and also assist in insulating the wires from each other. If
for any reason it is ever desired to have access to the wires in the conduit at any
point of the line it is only necessary to dig down thereto and prize off the lid of
one section by a pinch bar and for this purpose the lower edges of the lids are

page_text: formed with notches uz to admit the point of the bar between the edge of the lid
and the trough. If it is found difficult to prize off the lid, it can then be easily
broken or cut by a hammer or chisel or readily bored into by a boring tool' and
after the broken lid is thus removed access may be readily had to the wires within
and any desired examination removal or connection made, after which the joints
of the conduit may be cleaned off with a, trowel and a new lid cemented on in the
place. of the old one and connections led from the new lid if desired, through holes
bored therein or through nipples formed thereon as will be understood, all of which
may be done with very little trouble or expense thus presenting an important
advantage in favor of this system,
From what has been already stated and illustrated it is therefore believed that
the important advantages of this system of wire conduit in cheapness permanency,
strength and ease of accessibility at any point are sufficiently obvious, without
requiring any further description to commend it to practical electrical engineers.
I have described the conduit as being formed preferably of pottery or earthen-
ware as this has prime advantages but the peculiar bisected construction of the
conduit as described is not of course necessarily confined to this or any other
material. Among the other materials however which may be mentioned are
hydraulic cement glass or cast iron, but I do not recommend any of these in
preference to common baked pottery or brick ware. The lower part of the conduit
might however be made of earthenware and the upper part of galvanized sheet
iron, but I strongly recommend the preferred construction described. The lids of
the conduit which are to be provided with manholes, nipples or elbows might
with advantage be made of cast or sheet iron, while all the rest were made of
earthenware.
Having now described the said invention and the manner of performing the
same, as communicated to me by my foreign correspondent I wish it understood
that what I claim and desire to protect under the hereinbefore in part recited
Letters Patent is.
First. An underground wire conduit formed in longitudinal sections of trough
shape fitting end to end with respectively overlying and underlying ledges m lat
their meeting ends forming overlapping joints substantially as and for the purpose
set forth.
Second A sectional conduit formed in two overlying sections adapted to be
ceinented together with the prizing notclies u formed on the meeting edge of one
or both of the sections substantially as and for the purpose set forth
".
In witness whereof I the said Alfred Julius Boult have hereunto set my hand
and seal this fourth day of October in the Year of Our Lord One
thousand eight hundred and eighty two.