IMPROVEMENTS IN LAYING ELECTRICAL CONDUCTING WIRES IN THE GROUND AND ALSO IN AN INSULATING COMPOUND TO BE USED FOR ELECTRICAL PURPOSES GENERALLY
Year: 1883

page_text: LETTERS PATENT to Herbert John Allison, of the firm of Allison Brothers,
Patent Agents, of 41 Southampton Buildings, Holborn, in the County of
Middlesex, for an Invention of "IMPROVEMENTS IN LAYING ELECTRICAL
CONDUCTING WIRES IN THE GROUND AND ALSO IN AN INSULATING COMPOUND
TO BE USED FOR ELECTRICAL PURPOSES GENERALLY" communicated to him
from abroad by John Greives and John Henry Bleoo, of Paterson, New Jersey,
United States of America
COMPLETE SPECIFICATION filed by the said Herbert John Allison at the
Office of the Commissioners of Patents on the 29th May 1883.
HERBERT JOHN ALLISON, of the firm of Allison Brothers, Patent Agents,
of 41 Southampton Buildings, Holborn, in the County of Middlesex, " IMPROVE-
"
5MENTS IN LAYING ELECTRICAL CONDUCTING WIRES IN THE GROUND AND ALSO IN
AN INSULATING COMPOUND TO BE USED FOR ELECTRICAL PURPOSES GENERALLY
communicated to me from abroad by John Greives and John Henry Bleoo, of
Paterson, New Jersey, United States of America.
This invention relates to an improved system of laying electrical conducting
wires in the ground; and it includes an improved conduit for such purpose, a
device for discharging the induced electricity from the insulating coating of each
wire, an improved manhole connecting with the conduit, and an improved
insulating compound for use in laying the wires or in other situations.
The improved conduit is formed by coating a metallic pipe internally with any
insulating composition adapted to adhere permanently; the discharging device
consists in a naked copper wire laid inside the conduit and connected at both ends
or at intervals, with the ground or the exterior of the metallic conduit, and having
the exterior insulated coating of each enclosed conductor electrically connected
with it.
The man-hole is constructed with an iron well-casting, an internal insulated
wooden chamber, and water-tight connections through the sides of the well-casting
and chamber for the respective conduits leading to the chamber.

page_text: The insulating compound consists in a fused mixture of common rosin or
colophony with the hydrate or carbonate of lime.
The nature of the invention will be understood from the annexed drawings in
which Fig. 1 is a plan of the man-hole; Fig. 2 is a central vertical section of the
same, with a short portion of the conduit connected to each of two opposite sides;
and Fig. 3 is a plan of several blocks of ground having the man-holes and conduits
applied thereto.
Fig. 4 is a perspective view of a section of the conduit; Fig. 5 is a vertical
longitudinal section of a conduit and the walls of the well-castings and chambers
to which it is connected; Fig. 6 is an end view of the conduit and enclosed wires,
showing the connections from the latter to the discharging wire; and Fig. 7 is a
sectional side view of one end of the conduit, showing the direct connection of the
discharging wire with the coatings of the conductors.
A is the conduit, formed by coating the inside with an adherent insulating
material; B, B are the enclosed conducting wires, each of which is also coated
externally with an insulating material; C is the discharging wire, D a binding
post inserted through the lining of the conduit and connected to the wire C,
and E is a wedge for holding the wire C in a hole at one end of the pipe A in
lieu of the post D. The insulating lining is lettered Z. F is a nozzle (Figs. 5
and 6) inserted in the pipe to make a local connection; G is a cap to cover it until
it is used, and H is a service pipe enclosing the ends of one wire B.
"
The wires B, B are shown placed, without any cover or special arrangement, in
the bottom of the conduit A, and the latter is laid and connected with the man-holes,
in the following manner.
Referring to Fig. 3, the district in which the conducting wires are to be laid and
used, is divided into sections of several hundred feet, at the end of which, as at the
corners X and intermediate points X³, the well-castings I are sunk, and the
conduits laid from one to another and projecting several inches through the side of
the well-casting internally.
The conduits are made in sections of from six to ten feet in length to be coated
readily and perfectly upon their inside; and when laid in the ground, are provided
with screw-couplings A¹, as shown in Fig. 5, or joined by flanges and bolts or in
any other manner. A drag wire B', shown in Fig. 5, as drawn through the centre
of the conduit, is inserted in the same as it is laid and may be used subsequently
to insert the wires B from any man-hole, whenever required, in the usual manner.
The well-castings I are made to exclude all moisture from the wooden insulating
chamber J (Fig. 2), and are provided with man-hole covers K to afford access
inside; and with a screw sleeve a passed through its side and the wall of the
chamber J, at each point where the conduit penetrates it.
The sleeve fits, both, water-tight, and is made large enough to admit the conduit
and an annular packing caulked around it, as at b, b; the packing being inserted
after the fixtures have been properly set in place in the ground.
The chamber J is formed of wood, and rests upon wooden cleats c, c. placed
between its bottom and sides and the enclosing well-casting I to insulate it, and is
preferably coated internally with a waterproof and insulating composition of the
kind described herein.
The chamber is provided with a cover d, held in place by a removable bridge e,
having a set-screw fat its middle; and is provided with a water-tight packing, as
soft rubber, where it fits the top of the chamber, to exclude moisture.
The wires B, B are shown in Fig. 2 as connected with binding posts g upon
a switch board at one side of the chainber; and the latter is made of four or five
feet in diameter so that an operator can readily manipulate all the wires and alter
their connections as required.
The discharging wire operates as follows; it is shown connected with the ground
through the medium of the metallic conduit, the exterior of which is not insulated,
and it may be electrically connected with the metal of the conduit in either of the
methods shown herein, or otherwise.

page_text: Binding-posts like D, D may be inserted in the pipe, and the naked wire C be
suspended therein along the top of the conduit, or it may be laid among the
conductors B, B, and be fastened to the pipe A only at the ends where they
penetrate the chambers J and are easy of access. In such case the wire C can be
bent into a hole formed in the conduit, and jammed therein by a wedge E for
security; and the connection from the same to the wires B may be made by flat
strips of copper as at i in Figs. 5 and 6; or by coiling the wire C around and
among the conductors B, B, prior to connecting it to the pipe A.
The electrical charge inside each conductor induces a similar charge of opposite
electricity upon the outside of its insulating coating, which induction greatly
retards and deranges the desired operations of the operative currents transmitted;
and the effect of the connections i is to release the electricity thus bound upon the
exterior of each conductor, and to thus free the transmitted current from the
deranging influence.
The discharging wire is thus connected with the ground at each chamber J,
and the connections between it and the conductors are also made at the same
point the single discharging wire sufficing for all the conductors that may be
placed in the conduit, if their external coatings be electrically connected thereto.
The object of the construction described, for the conduit and man-hole pit, is to
secure an enclosure for the conductors, that shall not only be protected from
dampness at all points, but shall be itself electrically insulated so as to diminish to
the lowest degree the risk of losing the electrical currents.
It will be plain, from the drawings and description, that the conduit affords such
a protection, and prevents, in some degree, the loss of electricity from a conductor
whose own insulation may prove defective.
When the conduits are laid in the ground provision is made for tapping the wires
at any required intervals, as opposite to each building, by inserting a nipple as
at F, and covering the same with a cap G until it is wanted.
At any future time, the cap can be removed, and a service pipe H be coupled to
the nipple by a coupling E', in the usual manner.
The nipples and caps are preferably lined with an insulator like the conduit;
and to secure a cheap material for such purpose, I have invented the compound
of rosin and hydrate or carbonate of lime, which I prepare in the following
manner.
The rosin is melted and retained in a fused condition, while an excess of the
lime powder is stirred into and thoroughly incorporated with it, the resultant being
a compound of chemically different character from either of its ingredients.
This results from the acid character of the rosin, which consists chiefly of sylvic
and pinic acids; and the alkaline property of the lime powder, which is prepared
in the following manner.
The carbonate is prepared by taking common chalk and freeing it from all
silicious and foreign substances and then reducing it to very fine powder.
The hydrate is prepared by slaking the lime, either slowly in the air, or by the
application of a suitable proportion of water.
If the latter method be employed, care must be taken to supply enough water
or crystals of hydrate will be formed, and an excess of water must be avoided, to
prevent the formation of a wet paste in place of the dry powder required.
Either the hydrate or carbonate produces with the fused rosin, a compound
of apparently the same characteristics, resembling an artificial stone in appearance
and possessing a hardness and extreme tenacity entirely unlike either of the
separate ingredients.
The insulating quality of the compound is also so great that a film of it,
one-sixtieth of an inch in thickness, will resist a current of fifteen Ampères per
second.
The composition when fused, can be moulded into any desired form, or applied
to any surface; but if used to coat a flexible conductor, it requires a considerable

page_text: degree of ductility, which is readily imparted to it by stirring from two to five
per cent of a fixed oil like rosin oil into the mixture when fused.
With the addition of the fixed oil, the composition becomes almost as tough as
sole leather, and strongly adherent to metals; its tenacity is also all that is required
in a flexible coating for wires.
Any proportion of from fifty to ninety per cent of the lime powder may be used
in the composition, according to the hardness required, but I commonly use 35 per
cent of rosin to 65 of the lime powder.
This insulating material may be applied to conducting wires by heating them
and drawing them through a bath of the fused compound; and it may also, in a
fused state be applied to the inside of the conduits and chambers I employ, or to
any other objects requiring insulation in a similar manner.
t
Having thus described the nature of the said invention and the manner of
carrying the same into effect, what I claim is :—
1 The insulating compound herein described, consisting in the hydrate or
carbonate of lime mixed with fused rosin in the manner and proportions,
substantially as set forth.
2nd The means of rendering the said composition pliable, by the addition of a
fixed oil in the manner and proportions substantially as set forth.
3rd The improved conduit for electrical conductors, consisting in a metallic pipe
provided with a lining of an adherent insulating compound, substantially as set
forth.
4th The combination, with the insulated wires enclosed in the conduit, of the
naked discharging wire connected electrically with the ground and with the
insulating coatings of the conducting wires, substantially as and for the purpose
set forth.
5th The devices for enclosing the wires in an insulated casing in the ground,
consisting in the conduits A lined with insulating materials as described, and the
chambers J, insulated within well-castings I, and connected with the said castings
and with the conduits A, by the water-tight sleeves a and packing b, as herein
shown and described.
6th The means for tapping the main conduit for service connections without
boring the same or breaking its insulating lining, consisting in the nipples F
inserted in the conduit at suitable intervals and provided with removeable caps G;
the nipples and caps being lined with insulating material substantially as and for
the purpose set forth.
In witness whereof, I, the said Herbert John Allison have hereunto set my
hand and seal, this twenty-ninth day of May in the year of our Lord one
thousand eight hundred and eighty-three.
חננגו תיזזז
גום תII
J. ALLI
(S) NOSI