Year: 1889

page_text: I, GEORGE WASHINGTON COOK, of Detroit, Michigan United States of America,
Gentleman do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertuned in and by
the following statement:-
This invention relates to new and useful improvements in underground conduits for
electric wires, and the invention consists in the peculiar construction, arrangements
and combination of parts, whereby perfect insulation and freedom from loss by induc-
tion is obtained, while at the same time, the conduit can be built at a moderate cost
and at the same name, complies with all the requirements found necessary in the
application of such devices for laying telephone, telegraph and electric light wires
under ground.
The especial features of my construction consists in the novel manner of insulating
the wires which may be either naked or covered wires in any form; and another
feature of my conduit is its peculiar construction in sections of moderate length,
whereby the work of laying the conduit may be rapidly executed; all as more fully
hereinafter described and shown in the accompanying drawing, in which,
Figure 1 is a perspective view showing a section of my conduit as in the process of
construction.
Figure 2 is a cross-section thereof, and
Figure 3 is a perspective view showing my manner of securing the electric wires in
paper tubes.
My conduit consists, first, of an outer box made of well-seasoned lumber, and consists
of the bottom A, the sides B, B, and the top C, joined together in the form of a rect-
angular box in sections, in the following manner.
The sides B, B, are provided on the inner edges with tenons D and the top and
bottom boards A and C are provided with corresponding mortices to receive these
tenons. The ends of the bottom and top boards A and C are halved, one end being
halved on the upper face, and the other on the lower face, as shown in Figure 1, wherein E
and F show respectively halved ends of the bottom board of one section; the side
boards B are cut off at an angle at the ends, as shown in G in Figure 1, and these
CD
1

page_text: sides are secured to the bottom board by nailing, or otherwise and are shorter at one
end and correspondingly longer at the other end than the bottom board, so as to break
the joint between two sections of conduit, the top board of each section is left unsecured
until the conduit 13 ready to be laid in the ground. Sections of the conduit are thus
constructed of a suitable length, say 12 to 16 feet long, and if desired to secure the
permanency of the conduit when buried in the ground, the sections of conduit may be
previously treated by a wood-preserving process, such as impregnating them with
corrosive sublimate or any other of the well-known wood-preservatives, or they may
be varnished or painted on the outside It will be noticed that the sides, and the top
and bottom, of each section are interchangeable, which, in manufacturing the conduit,
naturally simplifies the work Before putting the sides and bottom of each section
together, the joints may be coated with paint, tar or similar compound, to render such
joint tight.
The wires are laid in the conduit in 'the following manner: 1 construct the paper
tubes H of suitable length, say two feet, slightly tapering from one end to the other,
so that the tubes may be joined on to each other by inserting the smaller end of one
tube into the larger end of another tube, allowing the tubes to telescope each other in
that way for a little distance and with the smaller end firmly wedged into the large
end These tubes have to be of suitable diameter to be readily strung upon the wine
or cable which they are intended to enclose. Before using them, however, I treat
them to a bath of melted paraffine in which I dip each tube so as to coat it thoroughly
both inside and out, and have it completely impregnated therewith, to which end 1
preferably use more or less porous material for manufacturing the tubes, which have
to be, however, of sufficient stiffness to permit their being firmly stuck together in the
manner described
In proceeding in laying my conduit, I first lay the box, minus the top board, into
the bottom of the trench, then I place at suitable distances apart insultating bridges I
upon the bottom board, preferably of moulded glass and shaped in such fashion as to
form suitable bearings J for holding the paper tubes, about equi-distant between the
top and bottom and at regular distances apart, if there are more than one wire or
cable to be placed in the conduit These insulating bridges I form in such a manne
that they have the least possible number of contacts with the sides and bottom of the
box, there being preferably small lugs K formed on the underside of the bidges, as
shown in Figure 1, or the underside of the bridges may be formed corrugated as shown
in Figure 3 The object of thus forming the insulating bridges is not alone to restrict
their contact with the boxes, but also to allow an insulating material with which the
boxes are filled up to flow around.
In joining the next section, the parts which form the joint are first coated with
some water proof material, such as tai or similar compound, and the laying of the
paper tubes which enclose the wire is proceeded with, in a similar manner as for the
preceding section, care being taken to have every tube firmly inserted with its smaller
end into the larger end of the preceding tube. Before paying any wires in the box,
I prefer to coat the box on the inside first with some water-proof compound preferably
a composition of tar, pitch or paraffine, after one or more sections have received the
paper tubes enclosing the wires, I fill the whole box full of a compound, preferably
of the kind already described, which I pour in hot, taking care that no empty spaces
are left. After filling the box with the compound, I lay on the cover, breaking joints
as shown in Figure 1 It will be noticed that in placing the cover on, some of the
compound with which the box is filled will be displaced, as the box when open holds
more than when closed, on account of the mortice and tenon engagement between
the sides and the top; thus the laying of the top ensures the complete fullness of the
conduit, while, at the same time, the material is not crowded out on the sides, and
therefore liable to prevent the formation of a tight joint, but must be displaced
end wise. After laying on the top, the latter is secured by nailing it down upon the
sides. From experimentally constructing conduits of this kind, I have ascertained
that from this manner of insulating the electric wires, the insulation of the wires is
absolutely perfect, and the moisture of the ground is permanently excluded.

page_text: By constructing the paper tubes as described, I have found that by merely sticking
the tubes into each other, as described, they form air tight joints, and as the paraffine
is not alone insulating, but water proof, all moisture is absolutely excluded from the
interior of the tubes, being besides completely buried into the compound, the insula-
tion of the paper tubes themselves is absolutely perfect; thus it is obvious that even
a naked wire is absolutely and permanently insulated by my conduit, and induction
is also reduced to a minimum.
It will be understood that the paper tubes, aside from their insulating quality,
insure the parallelism of the wires, thus keeping them out of mutually contact or
approach to each other, and also all possible displacement of the wires within
the box.
The construction of the boxes, as well as the manner of constructing the entire
conduit, increases the strength of the conduit, which at the same time very favourably
compares in price with other conduits.
I preferably construct the paper tubes of asbestos paper, which has a much longer
life than any other kind of insulating material, as it does not rot nor decay, nor is it
affected by heat.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim 18:
First. In a conduit for electrical conductors, in combination with an outer conduit
of an inner conduit or conduits of like paper tubes fitted one within the other,
substantially as described.
Second. A conduit for electrical purposes, consisting of a series of like paper
tubes, saturated with paraffine and taper-jointed together.
Third. In a underground conduit, the combination of the following elements, an
outer casing or box of substantially rectangular shape, insulating cross bridges
placed therein at intervals, an inner conduit or conduits consisting of paraffine,
taper-jointed paper tubes supported upon said cross bridges, and an insulating water-
proof compound filled into the outer conduit, substantially as described.
Fourth. The inner conduit, consisting of a series of asbestos paper tubes, substan-
tially as described.
Fifth. An underground conduit for electrical conductors, consisting of tubes
tapering from one end to the other, and adapted to be taper-jointed together, substan-
tially as described.
Dated this 7th day of May 1889.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.