Improvements in Electrical Conduits.
Year: 1897

page_text: Date of Application, 28th July, 1897-Accepted, 25th Sept., 1897
CUMI LEIE DI ECIFICATION.
Improvements in Electrical Conduits.
We HENRY LEWIS DOULTON, Potter, and CHARLES EDWARD MORRIS, Engineer,
both of Lambeth Pottery, Lambeth in the County of Surrey 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:-
Our invention has for its object improvements in the method of jointing butt
lengths of earthenware conduits for underground electrical conductors and in the
means of making branch connections with the conductors therein. Letters Patent
relating to such conduits have been granted to us numbered respectively 1371892
and 1290305.
In jointing butt lengths of conduit one to another by this invention, we use metal
collars to secure mechanical strength at the joints an example of which is shown
in Figs. 1 & 2. Each collar is in two parts a & b which embrace the ends of
adjoining lengths of conduit and are provided with lugs and clamped together by
bolts C, C, or other suitable means. The interior of the collar is recessed d, d, and
the upper part has an aperture e. To ensure that the ends of the conduits are firmly
clamped by the collar, this is made so that a space f, f, is left between the upper and
lower parts to allow for variation in the dimensions of the earthenware. This space
is covered on the outer side by the flanges g, g. The interior of the collar is provided
with fillets h, h, which grip the conduits as near as practicable to their extremities.
Liquid or molten cement is poured through the aperture e, its egress being prevented
by clay or other material and to prevent its entering the conduit, expanding mandrils
may be used as described in our Specification No. 1371892.
An alternative form of collar is shown in Fig. 3.
In making branch connections with the conductors within, lengths of conduit are
used which are divided longitudinally. These may be inserted when laying the
conduit, or they may be substituted for an ordinary length. Example is shown
in Figs. 4 & 5. Slots j, j, are provided at the ends for the passage of the branch
cables. A connecting piece K fits in the outer slot, the end of which is provided with
a socket or other means of connection. In making the joint with the next length
of conduit a special form of collar m is used, made with an aperture to take the
connecting piece.
An alternative method may be adopted for making branch connections with the
conductors within. A length of conduit is removed from the line. To facilitate this
operation, lengths nicked for splitting may be inserted, when laying the conduit, at
points where snch connections are likely to be required. The cable-connections
having been made, the length of conduit which has been removed is replaced by the
box shown in Figs. 6 & 7. This consists of a split length of conduit of special
formation. Flanges may be provided to enable a sound joint to be made between the
upper and lower portions. Throughout a portion of its length the upper wall is raised
to provide a pocket or cavity n and the interior webs are preferably cut away. On
one or both sides is an opening which takes the connection piece o. This is made
with flanges around its edges to fit the earthenware & is provided with a socket p or
other means of connection, which may be made in two pieces to be bolted together,
0.1.7.

page_text: as shown in the figure, or it may be made in one piece, in which case the branch
cables are threaded through it. In some cases the box may be laid with the pocket
on the under side.
Another method of making branch connections is shown in Figs. 8 & 9. A length
of conduit is removed from the line, and an iron box substituted. The box is divided
longitudinally, and the two portions are secured together by bolts. The box is
provided at each end with an interior annular cavity r, r. When fixing the box in
position a sound joint may be made with the adjoining lengths of conduit by filling
the cavity with cement through the aperture 8, 8. The box is provided with one or
more openings t for branch cables. The top of the box is raised to provide a space v
for the passage of branch cables above those resting within the ducts of the
conduit.
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. Collars for joining butt lengths of conduit substantially as described & shown
in Figs. 1 & 2.
2. Collars for joining butt lengths of conduit, substantially as described. & shown
in Fig. 3.
: 3. The means of providing for connections with cables within conduits substantially
as described & shown in Figs. 4 & 5.
4. A connection-box & branch socket substantially as described and shown
in Figs. 6 & 7.
5. A connection-box substantially as described and shown in Figs. 8 & 9.
6. The means substantially as described for providing for branch connections with
cables within earthenware conduits.
Dated this 97th dow of Tulu 1907