Improvements in Electric Conductors, and in Laying and Supporting Conductors within Conduits.
Year: 1889

page_text: Date of Application, 20th July, 1889
Complete Specification Left, 10th Apr., 1890-Accepted, 17th May, 1390
PROVISIONAL SPECIFICATION.
Improvements in Electric Conductors, and in Laying and Supporting
Conductors within Conduits.
I, ROOKES EVELYN BELL CROMPTON of Arc Works, Chelmsford, in the County
of Essex, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to further improvements connected with my invention of
underground conductors of electricity more particularly described in Letters Patent
No. 7655 of the 25th May 1888 already granted to me, and which I hereinafter refer
to as my former patent.
To facilitate the introduction and withdrawal of the copper strip from my culverts,
for some special cases I find it convenient to construct what I horeafter call "moveable
insulator carriages." These consist of a frame made of suitable materials supported
on three or more rollers or wheels. These wheels are preferably, though not necessarily
made of insulating material. On these frames are mounted any required number of
pairs of vertical insulators. Each pair of vertical insulators being connected by a
suitable strap or tie preferably made of metal, in the centre of which a third insulator
of roller form, having a grooved edge, is free to revolve. In the groove of this roller
lies the copper strip conductor. These insulator carriages are so made and arranged
that they can be readily drawn into and along the line of the culvert being so guided
that the conductor when supported by the grooved rollers occupies its correct position
in the culvert. It will be seen that by the employment of these insulator carriages,
I can, if I so desire it, construct a culvert with proper openings for access at very
considerable distances apart and can roof in the culvert and finish the surface of the
roadway, as I am able at any convenient time to draw in the copper strip conductor
through the openings and finally draw in a train of these insulator carriages which will
pass underneath one or more conductors and lift it or them into the required position
as the train advances along the culvert. I prefer to space my insulator carriages at
the required distance apart by lengths of wire rope made of galvanised steel or other
suitable material of sufficient strength and not liable to corrosion or decay. In such
eases where I wish to have several conductors in the same culvert and of these some of
them carrying currents differing very slightly in electro motive force as may be the case
when feeder mains lay alongside distributing mains, I can mount these on the same
pair of vertical insulators although on separate rollers, that is to say, that the con-
ductors will be only spaced apart by flanges between the rollers, which revolve on,
and are supported by a common axis, which in its turn is more thoroughly insulated
from the earth by the vertical insulators which support the strap. I sometimes employ
these insulator carriages only for points midway between the openings or surface
boxes but my older form of fixed insulators described in my former patent at or under
these surface boxes. In some cases I design and arrange these insulator carriages so
that they can be used in cast or wrought iron culverts consisting of pipes of
rectangular or circular cross section. In order to admit of the ready withdrawal of
any one of these insulator carriages, I so construct my openings or surface boxes
that sufficient space is given to one side of the line of conductors that each insulator
on being drawn to a point immediately opposite the surface box can be first
moved to one side and then lifted out of the surface box clear of the conductors.
I can employ this arrangement whether the culverts are completly constructed of
brickwork or concrete as described in my former letters patent or with the iron
culverts or culverts combined of ironwork brickwork and concrete.
In addition to the various straining devices described in my former patent I find
it convenient in certain cases to employ the following improved arrangement :-
In such cases where I desire to have a fixed abutment in order that 1 may strain

page_text: up any desired length of the copper strip conductor without the necessity of entting
the said strip, I build into the walls of the culvert or, fix to the cast iron culvert as
the case may be, at any convenient position opposite the surface box, one or more
pairs of cross bars according to the number of abutinents required. These may be
made of either iron covered with insulating material or of wood or of any material
of any transverse strength of which the surface is thoroughly insulated. These cross
bars are placed in pairs vertically above one another at sufficient distance apart to allow
of the strip passing between them. Each strip also passes through a bridge piece
made of iron or suitable material somewhat of the form of the well known bridge used
to hold up the internal manhole doors of steam boilers. The two ends of these bridge
pieces abut against the cross bars suitable glass insulators being interposed under
each end. The strip after passing through the hole in the centre of the arm can be
strained by any of the means described in my former patent and then fixed in position
either by pinching screws clamping it against one side of the hole in the bridge
piece or in some cases separate clamps may be employed made in two pieces and
formed that they occupy little side space which can be screwed firmly to the strip
just outside the eye of the bridge piece and thus prevent the strip passing back
through the eye and the strain being relaxed when the temporary straining screws
are removed.
In some cases where economy of side space has to be studied instead of these
clamps rivet and solder or rivet or solder suitable pieces on to the copper strip
itself.
In the cases above mentioned where several strips are employed in one culvert
which carry currents differing slightly in electro motive force I strain these up by
separate bridge pieces hearing on glass insulators common to both but sometimes I
make the bridge piece and insulator with two or more sets of holes so that I can
strain up and clamp more than one side of strip conductors, the conductors being
insulated from one another in the holo by the holes themselves being lined by
insulating material.
Where I find it necessary to employ straining devices at the extremities of portions
of the culvert constructed at a lower level than the adjoining portions I employ a
hell crank lever device somewhat as follows-1 mount a bell crank lever on a
fulcrum attached to any convenient part of the pit which connects the two portions
of the culvert. This hell crank lever has mounted on the arm which extends to the
lower portion of the pit a suitably formed in-ulator of preferably roller form, and at
a higher level in the pit-nearly on a level with the insulators-in the higher portion
of the culvert. I mount a 2nd insulator. The strip is arranged to pass from the
higher level over this last named insulator and under that mounted on the lower arm
of the lever. The straining is effected by the bell crank lever being moved or rocked
by screw gearing or other suitable mechanism so as to move the lower end of the
lever outwards and thus bring a strain on that portion of the conductor which lies
within the lower part of the culvert.
The screwing can conveniently be effected from above by any suitable key or
turning means.
In cases where I employ more than one conductor I can either mount the
conductors on separate levers or in the cases before referred to where the difference
of potential between the sum of these conductors is small I can mount more than
one of them on a level common to them all.
The same device might be used where the portions of the culverts although
substantially in the same plane or otherwise, are not in the same line on plan view.
The position of the bell crank lever will be altered accordingly.
Dated the 20th day of July 1889.
WM. BROOKES & SON,
55 & 56, Chancery Lane. London, Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Conductors, and in Laying and Supporting
Conductors within Conduits.
I ROOKES EVELYN BELL CROMPTON, of Arc Works, Chelmsford in the county of
Essex, Engineer 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 :-
This invention relates to further improvements connected with my invention of
underground conductors of electricity more particularly described in Letters Patent
of the United Kingdom of Great Britain and Ireland No. 7655 of the 25th May
1888 already granted to me and which I hereafter refer to as my former patent.
The electrical conductors referred to are those more particularly adapted for use in
conveying currents of electricity, for transmitting power and for electric lighting.
The straining of those conductors is effected by fixing at convenient intervals in
the length of the conduit, transverse bars made of wood or iron covered with
insulating material.
Between these anchoring supports the tapes forming the conductor are strained
taut by screw or other straining devices such as described in my former patent and
the required degree of tension is hereaftor maintained by clamps secured on the
tape by means of set screws. The said clamps bearing against metallic bridge pieces,
which metallic bridge pieces bear against the transverso bars, suitable insulators
being interposed to insulate them therefrom. Or the clamp may be formed in one
with the bridge piece. Each successive length of conductor is strained up in a
similar manner and continuity between the adjacent ends of the conductors after they
have been strained is effected by connections which can be attached to the strips in
any way best suited to form a good electrical contact.
The insulators both for the intermediate supports and at the anchoring supports
I employ are formed by preference of annealed or toughened glass. They may take
the form of cylinders the one end resting in a recess formed in the cross bars, and
the other end in a recess in the bridge piece. Each cylinder has its insulating
surface increased by a considerable number of deep grooves. I prefer to increase
the insulating qualities of these glass insulators by coating them with an insulating
varnish such as copal.
Although in most cases I prefer to construct my conduit of brickwork, or cement
concrete, in some cases I construct it of wood or metal. In most cases I prefer to
have a moveable cover or inspection chamber over each set of insulators but in such
cases where I cannot provide such means of access to the insulators, I sometimes
make these insulators moveable. I then call them chariots, they consist of a frame
carrying two or more vertical insulators connected at their tops by a metallic strip or
bridle within which an insulating disc or sheave is free to revolve. In the groove of
this roller or sheave lies the copper strip conductor. These chariots are so made and
arranged that they can be readily drawn into the line of the conduit, the conductor
being so guided and supported by the grooved rollers that it occupies its correct
position in the conduit. The chariots may be made large enough to carry supported
on their vertical insulators, any desired number of grooved rollers corresponding
with the total number of conductors that are placed in the conduit.
It will be seen
that with the employment of these chariots I can if I so desire it construct a conduit
with proper openings for access at a very considerable distance apart, and can roof in
the conduit and finish the surface of the roadway as I am able at any convenient
time to draw in the copper strip conductors through the openings at each end, and
finally draw in a train of these chariots which will pass underneath the conductors
and lift them up into the required position as the train advances along the conduit.
I prefer to space my chariots at the required distance apart by lengths of wire ropes,
galvanized steel wire or other suitable material of sufficient strength for the purpose,
and not liable to corrosion or decay. I sometimes insulate two conductors which vary

page_text: but slightly in E.M.F. mounting them on the same vertical insulators; they being
slightly separated by a midfeather formed on a roller common to the two of them.
It will be seen that by this method of mounting insulators on chariots and making
these into a train, that any insulator can be got at for repair by the simple means of
drawing the train of chariots forward to one of the end openings, and by taking off
the chariots one by one at that end and adding chariots one by ono at the other
end, until the desired chariot reaches the opening.
In some cases I find it convenient to make the conduits of cylindrical cross section
so that they may be pipes of wrought or cast iron, or even of earthenware or concrete.
In order to adapt the chariot system to these pipe conduits so that the chariots can be
guided to keep in line upon the bottom of the pipe, and so insure that the centre line
of the chariot is in a sufficiently vertical position, a tail piece can be attached to the
chariot frame which runs on and is guided by a special guide wire rope or strip,
lying inside the pipe.
So long as these pipe conduits are laid in a perfectly straight line this guiding
wire or strip should take up a central position as low down in the pipe as
possible.
In case however that it is desired to lay these pipe conduits so as to pass round a
curve this guiding wire serves as a means of forcing the chariots to take a slightly
inclined position.
The angle of inclination being that best suited to resist the pressure of the con-
ductors on the roller insulators.
It is evident that the direction of this pressure should correspond as closely as
possible with the centre line of the chariot which is at right angles to a line passing
through the axis of its carrying wheels or rollers.
So long as the conduit is in a straight line this pressure is a vertical one, but
when the pipe conduit is curved the line of pressure is the component of two forces,
viz. the vertical force due to the weight of the copper and the side force due to the
tendency of the strained conductor to approach a straight line. It is found that if
the guide wire above mentioned is strained round the curve so as to take the shortest:
possible line, it will no longer occupy the bottom of the conduit but will be strained
to either side of it according to the direction of the curve. When the chariots are
drawn into the pipe their tail pieces will therefore be diverted to one side and con-
sequently force the chariots to take an inclined position which will he found to be the
correct one to resist in the best possible manner the above forces.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 shows a sido view of a portion of a culvert containing the conductors cach
conductor consisting of two superimposed tapes.
Fig. 2. shews the same in plan view with three conductors in position.
Fig. 3 shews an end view of one of the insulators.
Fig. 4 shews the end view of one of the bridge pieces.
In Figs. 1 and 3 a shews the vertical insulator carrying the conductors in its
rectangular notch. in Figs. 1 and 2 shows the wooden transverse supports on which
the insulators rest. c shews the double transverse supports against which the bridge
piece drests, being insulated therefrom by the horizontal insulators e. ff are the
clamping screws by which the conductor is retained in position after it has been
drawn taut. It will be seen that the rectangular notch in the insulators a can be
made of any required depth so that any number of tapes can be superimposed
therein.
In the drawing the depth is shewn sufficient for two tapes only.
Fig. 5 shews in side view, Fig. 6 in end view and Fig. 7 in plan view a chariot
fitted complete with 6 vertical insulators and rollers sufficient to carry five
conductors.
Here are the vertical insulators which take the place of the insulators a in
Figs. 1 23 and 4