IMPROVEMENTS IN APPARATUS FOR THE CONDUCTION AND DISTRIBUTION OF ELECTRIC CURRENTS."
Year: 1881

page_text: LETTERS PATENT to Rookes Evelyn Bell Crompton, of Mansion House
Buildings, Queen Victoria Street, in the City of London, Engineer, for an
Invention of "IMPROVEMENTS IN APPARATUS FOR THE CONDUCTION AND
DISTRIBUTION OF ELECTRIC CURRENTS."
PROVISIONAL SPECIFICATION left by the said Rookes Evelyn Bell
Crompton at the Office of the Commissioners of Patents on the 21st
November 1881.
ROOKES EVELYN BELL CROMPTON, of Mansion House Buildings, Queen Victoria
Street, in the City of London, Engineer. "IMPROVEMENTS IN APPARATUS FOR
THE CONDUCTION AND DISTRIBUTION OF ELECTRIC CURRENTS."
I construct durable and economical insulated conductors, specially suitable
among other things for use in electric lighting on a large scale, in the following
manner
I take copper rods of proper, thickness and enlarge their ends by a suitable tool,
and on these enlarged ends I cut screw threads. The pitch of these screw threads
is so taken that at each junction, when the rods are placed in the order in which
they are to lie in forming the conductor, the screw threads on the two adjacent
ends are of slightly different pitch. Over those ends I screw a sleeve or socket.
When this is screwed up in the proper direction it forces the ends of the conductors
into very intimate contact.
The conductors so formed I insulate by placing one or more of them in tubes
of convenient section. In the case of two such conductors I prefer to have the
section of the tube rectangular. These tubes will in general be made of cast iron
for the sake of cheapness. The conductors may be maintained in the proper
position within tubes during the process of insulation by core nails or chaplets
such as are used for the support of the cores of pipes when cast horizontally.
I then place the tube containing the copper rods in a vertical position and pour

page_text: in purified blast-furnace slag, so as to form a vitreous insulating envelope thoroughly
insulating and protecting each of the conductors.
To insure perfect and intimato contact between the conductors and their
insulating envelope I sometimes enamel them before placing them in the tubes.
After the process of running in the vitreous matter is complete, and it has become
hard, I remove the chaplets or core nails. The holes left by them can be filled up
with insulating material of any durable kind, and the hole in the tube closed by
a screw plug if there is no desire to join a branch on to the main at that point.
If however it is intended to bring out a branch from the main at that point I
screw a copper plug of proper length into the metal of the conductor and bring
it out through a porcelain or glass washer, or surround it with other suitable
. insulating material, so as to prevent it coming into electrical contact with the
metal tubes or any other conductor in the tubes or the earth. The branch wires
are connected to theso copper studs preferably by borrowing a portion of the
branch wire, and after stripping it of any insulating material that may be on it,
taking a turn with it under the head of the copper plug before it is screwed down.
The hole through which the branch connection is made may with advantage be
covered by a cast iron hood or cap screwed down to the outer surface of the
envelope, and finally filled with pitch or gutta percha or other suitable insulator
to prevent the entrance of moisture.
I join the tubes or cases above described in which the conductors are placed by
means of short tubes made to slip over and fit somewhat closely upon the adjacent
ends of those containing the conductors, and join these short tubes to those over
which they slip by ordinary gasket and run lead joints, such as are used in the
case of cast iron water pipes. In the walls of these socket pipes holes are to bo
left through which melted pitch or other suitable insulating material can be poured,
so as to fill it up entirely after the joints above referred to have been securely
made and the holes are then filled up with screw plugs.
To enable these socket pipes to be used the conductors are made to project such
a distance beyond the tubes that contain them as to enable the junctions to be
most easily constructed. I prefer to make all bends and corners by providing
a series of pieces of various curvatures, as in the case of water pipes terminating
in straight ends of sufficient length to allow of the use of socket pipes as above
described. There is no difficulty in casting the slag in pieces of such shape.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Rookes Evelyn Bell Crompton in the Great Seal Patent Office on
the 20th May 1882.
ROOKES EVELYN BELL CROMPTON, of Mansion House Buildings, Queen Victoria
Street, in the City of London, Engineer. "IMPROVEMENTS IN APPARATUS FOR
THE CONDUCTION AND DISTRIBUTION OF ELECTRIC CURRENTS."
I construct durable and economical insulated conductors, specially suitable among
other things for use in electric lighting on a large scale, in the following manner :-
I take copper rods of proper thickness and enlarge their ends by a suitable tool, and
on these enlarged ends I cut screw threads. It will be understood that the ends
are thus enlarged to preserve the effective section of the conductor from being
reduced at the joint, but otherwise it is not necessary to or forms part of my
Invention
The pitch of these screw threads is so taken that at each junction, when the rods
are placed in the order in which they are to lie in forming the conductor, the screw
threads on the two adjacent ends are of slightly different pitch. Over these ends
I screw a sleeve or socket. When this is screwed up in the proper direction it
forces the ends of the conductors into very intimate contact. The way in which
this is to be done will be readily understood from the Drawings. The screw threads
on the extreme ends of the rods are stripped for a little distance to allow of the rods
being so screwed together, or some other equivalent method is used.
The conductors so formed I insulate by placing one or more of them in tubes of
convenient section. In the case of two such conductors I prefer to have the section
of the tube rectangular.
These tubes will in general be made of cast iron for the sake of cheapness. The
conductors may be, if desired, maintained in the proper position within the tubes
during the process of insulation by core nails or chaplets, such as are used for tho
support of the cores of pipes when cast horizontally; I then place the tubes con-
taining the copper rods in a vertical position, and pour in purified blast furnace
slag, so as to form a vitreous insulating envelope thoroughly insulating and
protecting each of the conductors. To insure perfect and intimate contact between
the conductors and their insulating envelope I prefer to enamel them before placing
them in the tubes.
After the process of running in the vitreous matter is complete, and it has
become hard, I remove the chaplets or core nails. The holes left by them can be
filled up with insulating material of any durable kind, and the hole in the tube
closed by a screw plug if there is no desire to join a branch on to the main at that
point. If however it is intended to bring out a branch from the main at that
point I screw a copper plug of proper length into the metal of the conductor, and
bring it out through a porcelain or glass washer; or surround it with other suitable
insulating material, so as to prevent it coming into electrical contact with the
metal tubes or any other conductor in the tubes or the earth. Tho branch wires
are connected to these copper studs preferably by baring a portion of the branch
wire, and after stripping it of any insulating material that may be on it, taking a
turn with it under the head of the copper plug before it is screwed down. The
hole through which the branch connection is made may with advantage be covered
by a cast iron hood or cap screwed down to the outer surface of the envelope,
and finally filled with pitch, or gutta percha, or other suitable insulator to prevent
the entrance of moisture. The insulating material should if possible be poured in
in a fluid state through a hole in the cap, which should finally be secured by a
screw plug.

page_text: I join the tubes or cases above described in which the conductors are placed by
means of short tubes made to slip over and fit somewhat closely upon the adjacent
ends of those containing the conductors, and join these short tubes to those over
which they slip by ordinary gasket and run lead joints, such as are used in the case
. of cast iron water pipes, or it may be found convenient to use rubber packing, or
rubber rings, or other well known modes of making such joints water tight, and at
the same time not perfectly rigid, to allow for the movements caused by expansion,
settlement of the ground, or other like causes. In the walls of these socket pipes
holes are to be left, through which melted pitch or other suitable insulating material
can be poured, so as to fill them up entirely after the joints above referred to have
been securely made, and the holes are finally filled up with screw plugs. To enable
these socket pipes to be used the conductors are made to project such a distance
beyond the tubes that contain them as to enable the junctions to be most easily
constructed. I prefer to make all bends and corners by providing a series of pieces
of various curvatures, as in the case of water pipes, terminating in straight ends
of sufficient length to allow of the use of socket pipes, as above described. There is
no difficulty in casting the slag in picces of such a shape.
But that the Invention may be fully understood I will, by the aid of the
accompanying Drawings, proceed to describe means I adopt in carrying the same
into effect.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shews a transverse section of a tubo C of cast iron or other suitable
material containing two conductors A, A, of copper enamelled, and theso
conductors A, A, arc imbedded in and insulated from each other and from the
containing tube or case C by means of the mass of slag or other suitable vitreous
inaterial B, which fills the remaining space in such case.
Where it is desired to bring out branches from the conductors A, A, I screw
into the conductors A, A, copper plugs a, a, passing such plugs through porcelain,
glass, or other insulating washers d, d, which are screwed or otherwise secured
into the case C, and to these plugs a, a, I attach suitable connecting wires or
leads c, c, by means of the nuts b, b, or other suitablo connections.
Figure 2 shews by a longitudinal plan view, partly in section, an arrangement
of parts adapted for connections of portions of tubes C and their contained
conductors A, A.
The end portions e¹, es, of the conductors A, A, are somewhat enlarged and aro
formed with screw threads thereon, adjoining ends being as shewn alternately
formed with threads of finer pitch e² and coarser pitch e', and over these are
passed and screwed correspondingly threaded socket pieces D, D, which thereby
hold these parts together.
The conductors thence pass into and are embedded in the masses of slag B, B,
partly within the sleeve piece E and thence to within the tubes or cases C, C,
which are passed to within the spaces F of the piece E which serves to connect
those part tubes.
Figure 3 shews a section of a single core or conductor A with its enamel
covering e, its insulating coating of slag B, and containing metal tube C, which
tube may be conveniently formed of wrought iron. This arrangement will be found
particularly convenient when two conductors are not required.
Figuro shews a section of another arrangement of parts somewhat similar
to that shewn by Figure 1, but more particularly adapted for being placed in the
footways of roads. The like letters of reference indicate like parts, as in Figure 1,
and the description thereof applies equally well to this arrangement, except that
in this arrangement of tubo or case C, one side (the upper side as shown) is
adapted for removal in the form of a lid C', affording means of easy access to the
rods or conductors and their insulating covering and the branch connections, and
these branches 6 are applied from the sides of the case c. The covers c¹ may be
roughened or formned so as to afford good foothold.

page_text: Having thus described my Invention and means which I adopt in carrying the
same into effect, I would have it understood that I do not confine myself to the
precise form of the parts shewn and described, as these may be varied, but what I
do claim is,-
Firstly. The manufacture and employment of insulated conductors for conducting
and distributing electric currents consisting of one or more metal rods connected,
insulated, and protected in manner substantially as shewn and described.
Secondly. The method of insulating copper or other metal rods to be used as
conductors of electric currents by first enamelling them, and subsequently
surrounding them by purified slag, glass, or other suitable material of a vitreous
nature, substantially as herein described.
Thirdly. The use of the differential screw coupling herein described as a means
of obtaining effective electrical contact between the ends of the rods of conductors
for the conduction and distribution of electric currents.
In witness whereof, I, the said Rookes Evelyn Bell Crompton, have hereunto
set my hand and seal, this Nineteenth day of May, One thousand eight
hundred and eighty two.
Witness,
ALFRED G. BROOKES,
ROOKES EVELYN BELL CROMPTON. (LS.)
59, Chancery Lane,
London.