IMPROVEMENTS IN APPARATUS FOR THE CONDUCTION AND DISTRIBUTION OF ELECTRIC CURRENTS
Year: 1882

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 15th
November 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
33
My invention relates to insulated conductors specially suitable among other
things for use in electric lighting on a large scale
As an improved means of insulating the copper rods described in my patent
N° 5080 dated November 21st 1881 I use india rubber or other suitable elastic
gum, as the insulating material, and apply it in the following manner.
I coat the copper rod with the india rubber or other insulating gum by winding
it on in the form of a spiral strip, applied longitudinally the edges being afterwards
united by heat, or other suitable means, so as to make the coating continuous
After treating the coating, with any one or several of the agents known as
vulcanizing or curing agents such as sulphur, ozokerite et cetera I place the rod
thus covered with insulating material within the sheathing tube, which may be of
cast iron wrought iron, brass or other suitable material; I then subject the whole
to a high temperature maintained for a sufficient period of time to cause the
vulcanizing or curing agent to enter into intimate combination with the insulating
gum and thus complete the process.
This vulcanizing or curing process usually carried out by placing the article
enveloped in the gum and curing agents in a metal mould and then subjecting it
to the temperature and finally removing it from the mould when the process is
complete; but according to my invention I utilize the sheathing tube itself as the

page_text: mould, and the pressure afforded by the increasing bulk or swelling up of the gum
itself under the curing process to supply the pressure requisite to force the
insulating material into such very intimate contact with the surface of the copper
rod and the inner surface of the sheathing tube that the insulating gum becomes
cemented to both of them.
I thus obtain an extremely dense compact form of insulation free from porosity,
very elastic and thus allowing the copper rod and iron pipe to adjust themselves
sufficiently under changes of temperature without liability of cracking the insulating
gum
To prevent extrusion of the insulating material at the two ends of the sheathing
pipe during the curing process, I close them by suitably fitted screwed caps or
otherwise; I prevent excess of pressure or the collection of gases during the curing
process by providing vent holes at suitable intervals along the sheathing pipe,
these vent holes can be afterwards stopped by plugs.
This arrangement of utilizing the sheathing pipe as a mould, in other words of
vulcanizing or curing the insulating material within its own sheathing pipe can be
used for any curing process for conductors and distributers of electric currents
whenever the original gum or material to be cured increases in bulk during the
curing process.
Another part of my invention relates more particularly to the method of forming
the joints of the sheathing pipes above described.
I effect this by thickening the ends of the sheathing pipes, either by screwing on
to them ferrules and brazing them fast in position or in any suitable manner
enlarging them sufficiently to enable a screw thread to be cut on the enlarged ends,
the diameter of the bottom of the thread of the screwed part being of greater
diameter than the external diameter of the rest of the pipe.
To make the joints after having connected the ends of the copper rods in the
manner described in my Patent No 5080 by a differential screw coupling or by any
other coupling which may be found convenient, I slide over the two ends of the
sheathing pipe a short cast iron sleeve which had been slipped back onto the pipe
before they had been laid in position, this sleeve is of such length that, when in
position centrally over the joints there is sufficient of the screwed portion of the
pipe outside the sleeve to permit of a lock, or jam nut or connecter being screwed
on from each end; a rubber washer is introduced between the jam nut and the end
of the sleeve so as to make the joints perfectly tight, and prevent the entrance of
moisture.
This sleeve is formed somewhat similar to the T pieces usually used for
connecting the ends of three wrought iron pipes, the stem of the T being a hole of
comparatively small diameter, and screwed internally whenever it is desired to
take a branch off the main; I utilize this T as a means of connecting the branch
main which must be of less diameter than the internal diameter of the T.
I pour in melted insulating material through the annular space thus left, and
so fill up the sleeve joint with insulating material; this insulating material may be
any of the various paraffin, Chatterton's compound, marine glues or other suitable
material, after the insulating material has been poured in, and while it is still fluid,
I apply pressure to it by screwing a long plug into the T, where a branch is taken
off, this plug will be tubular, somewhat similar to the gland of a stuffing box, but
where a branch is not needed, this plug will be solid; by this means I ensure that
every portion of the joints is thoroughly filled with insulating material free from
porosity

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 12th May 1883.
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."
1
My invention relates to insulated conductors specially suitable among other
things for use in Electric lighting on a large scale
As an improved means of insulating the copper rods described in my Patent
No 5080 dated the twenty first day of November One thousand eight hundred and
eighty one I use india rubber or other suitable elastic gum as the insulating material
and apply it in the following manner.
I coat the copper rod with the india rubber or other insulating gum by winding
it on in the form of a spiral strip applied longitudinally the edges being afterwards
united by heat, or other suitable means so as to make the coating continuous
After treating the coating with any one or several of the agents known as
vulcanizing or curing agents such as sulphur ozokerite et cetera I place the rod
thus covered with insulating material within the sheathing tube which may be of
cast iron, wrought iron, brass or other suitable material I then subject the whole
to a high temperature maintained for a sufficient period of time, to cause the
vulcanizing or curing agent to enter into intimate combination with the insulating
gum and thus complete the process.
This vulcanizing or curing process is usually carried out by placing the article
enveloped in the gum and curing agents in a metal mould and then subjecting it to
the temperature and finally removing it from the mould when the process is complete
but according to my invention I utilize the sheathing tube itself as the mould, and
the pressure afforded by the increasing bulk or swelling up of the gum itself under
the curing process to supply the pressure requisite to force the insulating material
into such very intimate contact with the surface of the copper rod and the inner
surface of the sheathing tube that the insulating gum becomes cemented to both of
them.
I thus obtain an extremely dense compact form of insulation free from porosity,
very elastic, and thus allowing the copper rod and iron pipe to adjust themselves
sufficiently under changes of temperature without liability of cracking the
insulating gum.
To prevent extrusion of the insulating material at the two ends of the sheathing
pipe during the curing process I close them by suitably fitted screwed caps or
otherwise, I prevent excess of pressure, or the collection of gases during the curing
process by providing vent holes, at suitable intervals along the sheathing pipe these
vent holes can be afterwards stopped by plugs
This arrangement of utilizing the sheathing pipe as a mould in other words of
vulcanizing or curing the insulating material within its own sheathing pipe can be
used for any curing process for conductors and distributors of electric currents
whenever the original gum or material to be cured increases in bulk during tho
curing process.
Another part of my invention relates more particularly to the method of forming
the joints of the sheathing pipes above described
I effect this by thickening the ends of the sheathing pipes, either by screwing on
to them ferrules and brazing them fast in position or in any suitable manner
enlarging them sufficiently to enable a screw thread to be cut on the enlarged ends,
the diameter of the bottom of the thread of the screwed part, being of greater
diameter than the external diameter of the rest of the pipe

page_text: To make the joints after having. connected the ends of the copper rods in the
manner described in my said Patent N° 5080 by a differential screw coupling or
by any other coupling which may be found convenient: I slide over the two ends
of the sheathing pipe a short cast iron sleeve, which had been slipped back onto
the pipe before they had been laid in position, this sleeve is of such length that
when in position centrally over the joints there is sufficient of the screwed portion
of the pipe outside the sleeve to permit of a lock or jam nut or connecter being
screwed on from each end; a rubber washer is introduced between the jam nut, and
the end of the sleeve, so as to make the joints perfectly tight and prevent the
entrance of moisture.
This sleeve is formed somewhat similar to the T pieces usually used for
connecting the ends of three wrought iron pipes, the stem of the T being a holo of
comparatively small diameter and screwed internally whenever it is desired to take
a branch off the main. I utilize this T as a means of connecting the branch main
which must be of less diameter than the internal diameter of the T.
I pour in melted insulating material through the annular space thus left and so
fill up the sleeve joint with insulating material this insulating material may be
of any of the various paraffin, Chatterton's compound, marine glues or other
suitable material. After the insulating material has been poured in and while it is
still fluid, I apply pressure to it by screwing a long plug into the T, where a
branch is taken off, this plug will be tubular, somewhat similar to the gland of a
stuffing box but where a brauch is not needed, this plug will be solid; by this
means I insure that every portion of the joints is thoroughly filled with insulating
material free from porosity.
Having thus described the nature of my said invention and the means employed
by me in carrying the same into effect I would have it understood that I do not
confine myself to the precise details herein set forth But what I do claim is the
Improvements in apparatus for the conduction and distribution of Electric currents
as herein described
In witness whereof I the said Rookes Evelyn Bell Crompton have hereunto
set my hand and seal this twelfth day of May in the year of our Lord
One thousand eight hundred and eighty three.
Witness
ALFRED G BROOKES
59 Chancery Lane
London.
REB CROMPTON (L.S.)