Improvements in Electric Mains and in Apparatus used in their Manufacture.
Year: 1890

page_text: Date of Application, 13th Aug., 1890
Complete Specification Left, 11th May, 1891-Accepted, 4th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in Electric Mains and in Apparatus used in their
Manufacture.
I, SEBASTIAN ZIANI DE FERRANTI of 120 Fellows Road, Hampstead in the
County of Middlesex, Electrician, do hereby declare the nature of this invention
to be as follows:-
My improvements relate to electric mains composed of comparatively rigid
conductors in short lengths coupled together end to end. In order to facilitate the
winding of paper or fabric which has been saturated with paraffin or other insulating
material around each length of conductor to insulate it as described in an appli-
cation for Patent made by me No. 16237 in 1889 I employ a pair of horizontal
parallel rollers on which to support the conductor as the paper is being wound
around it and cause the conductor to be pressed down on to the supporting rollers
by a weighted roller.
In order to avoid putting strain upon the paper as it is being wound around the
conductor I cause the conductor to be revolved by gearing at its ends and also
cause the supporting rollers to be driven nearly up to the same surface speed as
that of the paper which is being wound onto the conductor so that there may be
but little rubbing of the paper against the surface of the supporting rollers the
upper roller might also be driven if desired.
In other respects the machine may be constructed in the manner described in my
former application for Patent above mentioned.
To facilitate the joining together of lengths of electric mains composed of
concentric tubular conductors which are separated from one another by insulating
material I form the ends of the lengths in such a manner that they can be coupled
without using short coupling pieces to couple the outer tube or tubes.
The electrical connection between the adjoining ends of the inner tubular con-
ductors may be made as described in former Patents granted to me by a short
length of copper rod forced for a distance into the two ends.
One end of the outer tubular conductor may for a distance be reduced in
diameter so that it may be made to enter the unreduced end of the outer tubular
conductor of the next length.
Similarly if there is a protecting tube outside the insulation by which the outer
conductor is surrounded this outer protecting tube may be formed with one end
reduced in diameter for a distance to enter the unreduced end of the next
length.
When the ends of two lengths of main so formed have been brought together
and the end of one forced into the end of the other they may be held together by
forming a number of indented grooves or corrugations around the outer tube where
one has cutered into the other.
In place of reducing the outer tubular conductor and protecting tube at one end
they might be enlarged-or the outer tubular conductor might be composed of two
tubes fitting one within the other. The inner tube might at each end be stopped
short at a distance from the end and the outer one be reduced in diameter at one
end to the diameter of the inner tube so that such reduced end may be made to
enter the unreduced end of the outer tube of the next length.
The ends of the insulation by which the inner conductor is separated from the
outer I make coned and to fit together as described in the application for Patent
above mentioned.
In place of making the mains in lengths each of which is complete in itself I in
some cases make them with each length of inner conductor and its insulation

page_text: separate from the lengths of outer conductor and their insulation and in putting
them together I arrange that the joints between the lengths of inner conductor
shall be intermediate of the joints of the outer conductor, so that when a length or
lengths of. inner conductor have been put in place a length or lengths of outer
conductor may be slipped over it and secured-then again another length of inner
conductor and so on.
Thus the joints can readily be made one after the other.
There may be insulation on the interior of the outer tube as well as on the
exterior of the inner tube.
When the ends of two lengths of cuter tube have been brought together they
may be held by a short length of tube embracing both of them and having
corrugations indented into it all around its circumference.
COMPLETE
SPECIFICATION.
Improvements in Electric Mains and in Apparatus used in their
Manufacture.
1, SEBASTIAN ZIANI DE FERRANTI, of 120 Fellows Road, Hampstead, in the
County of Middlesex, Electrician, 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 :-
My improvements relate to electric mains composed of comparatively rigid
conductors in short lengths coupled together end to end. In order to facilitate the
winding of paper or fabric which has been saturated with paraffin or other insulating
material around each length of conductor to insulate it as described in the Specifi-
cation of my Patent No. 16237 in 1889 I employ a pair of horizontal parallel
rollers on which to support the conductor as the paper is being wound around it
and cause the conductor to be pressed down on to the supporting rollers by a
weighted roller:
In order to avoid putting strain upon the paper as it is being wound around
the conductor I cause the conductor to be revolved by gearing at its ends and also
cause the supporting rollers to be driven nearly up to the same surface speed as
that of the paper which is being wound onto the conductor so that there may be
but little rubbing of the paper against the surface of the supporting rollers-the
upper roller might also be driven if desired.
In other respects the machine may be constructed in the manner described in the
Specification of my Patent above mentioned.
In Figure 1 of the annexed drawings 4 is a transverse section of the tubular
conductor upon which the insulating sheets are to be wound. b and c are two
rollers on which the conductor lies. d is a third roller which presses upon it
on the upper side. e is a trough usually containing melted paraffin in which the
parts a b c and d are contained. The rollers and c replace the V groove
described in the Specification of my former l'atent. The roller d can be
driven by suitable gearing which at the same time that the roller rotates
permits it to rise as the lapping of paper or other insulating sheets around
the conductor a increases its diameter. The rollers and c are driven and for
this purpose I lead their necks or axes out through the end of the trough e
preferably through a gland or stuffing box and form pinions upon them; these
pinions engage with the teeth of a wheel which receives motion by a belt and
pulley or otherwise from a running shaft it may be from the back shaft K of my
Specification No. 16237 of the year 1889. The conductor a is driven as heretofore
except that I now employ a driving belt passing around continuous cone pulleys
and as the diameter of a increases and the roller d rises I cause the belt to be
automatically shifted along the cone pulleys so as to maintain an approximately

page_text: uniform surface speed on a notwithstanding the increase in diameter resulting from
the lappings. The surface speed is or should be slightly greater than the surface
speed of the rollers b and c. By these means I lessen the strain upon the sheets of
paper or insulating material in the winding process and I also cause the winding to
he performed at a more regular speed and with more uniform pressure.
To facilitate the joining together of lengths of electric mains composed of con-
centric tubular conductors which are separated from one another by insulating
material. I form the ends of the lengths in such a manner that they can be
coupled without using short coupling pieces to couple the tube or tubes.
The electrical connection between the adjoining ends of the inner tubular con-
ductors may be made as described in my Specification No. 12505 in the year 1888,
or by a short length of copper rod forced for a distance into the two ends, or in
any of the methods hereafter described for jointing the outer tubular conductors.
One end of the outer tubular conductor may for a short distance be reduced in
diameter so that it may be made to enter the unreduced end of the outer tubular
conductor of the next length.
Similarly if there is a protecting tube outside the insulation by which the outer
conductor is surrounded this outer protecting tube may be formed with one end
reduced in diameter for a distance to enter the unreduced end of the next length.
When the ends of two lengths of main so formed have been brought together and
the end of one forced into the end of the other they may be held together by
forming a number of indented grooves or corrugations around the outer tube where
one has entered into the other.
Figure 2 shows in longitudinal section portions of two lengths of an electric main
jointed together in accordance with my invention.
a is the inner tubular conductor usually of copper. bis the insulation preferably
of paraffined paper lapped around the conductor a in the manner already described.
c is the outer tubular conductor also preferably of copper. d is insulation preferably
of paraffined paper on the outside of c. e is the protecting tube outside of all; it
may be of iron, steel, or other suitable substance.
The insulating material on one end of the conductors a is formed conical at the
end and that on the other is so formed as to project beyond the extremity of the
conductor thus forming a socket for the coned end. The conductor e is slipped on
over the insulation band by drawing through a die is made to fit tightly onto it.
The end of one of the conductors c where they meet and are to be jointed together
is reduced so that it may be able to enter the end of the conductor c in the socket
part. I similarly prepare the ends of the outer protecting tubes and of the
insulation within them. The two conductors a are joined by the piece of copper
rod jammed tightly into their ends.
The two lengths of the electric main when thus prepared are brought together
and are forced home into one another by strong pressure.
Afterwards the outer
tube e where it overlaps the inner has a series of annular grooves formed in it.
This is done by means of a tool in which are three small rollers of hard steel which
can be forced together by a screw or otherwise whilst the tool is turned around the
joint and the joint is nipped between the rollers. In place of reducing the outer
tubular conductor and protecting tube at one end, they might be enlarged as is
shewn in Figure 3 of the drawings. Or the outer tubular conductor and protecting
tube might be composed of two tubes fitting one within the other. The inner tube
might at each end be stopped short at a distance from the end and the outer one be
reduced in diameter at one end to the diameter of the inner tube so that such
reduced end may be made to enter the unreduced end of the outer tube of the next
length.
Figure 4 illustrates this method of jointing. It will be seen that in each case the
ends of the insulation by which an inner conductor is separated from the outer
I make coned and to fit together as described in the Specification of my former
Patent above mentioned.
According to another part of my invention, in place of making the maius in

page_text: lengths each of which is complete in itself 1 in some cases make them with each
length of inner conductor and its insulation separate from the lengths of outer
conductor and their insulation and protecting tube. The ends of the parts are
In
adapted to fit together preferably in any of the manners already described.
putting them together arrange that the joints between the lengths of inner
conductor shall be intermediate with the joints of the outer conductor, so that when
a length or lengths of inner conductor have been put in place a length or lengths of
outer conductor may be slipped over and secured-then again I place another
length of inner conductor and so on. The protecting tubes may be similarly
treated.
Thus the joints can readily be made one after the other.
If desired the interstices between the parts may be filled with a fluid semi fluid
or other insulating material fluid or plastic when hot forced in by means of a
pressure pump.
There may be insulation on the interior of an outer conducting or protecting
tube as well as on the exterior of an inner tube in which case I form the layer of
insulation upon a mandril and then clothe it with a tube as already described.
The mandril may be made in parts in order that it may be more casily with-
drawn.
When the ends of two lengths of outer tube have been brought together they
may be held by a short length of tube embracing both of them and having
corrugations indented into it all around its circumference by means of a suitable
tool as already described. Or the lengths of the outer tube may be adapted so that
their ends enter the one into the other as already described.
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 1
claim is :-
1. The improvement herein described for covering short lengths of a com-
paratively rigid conductor with sheets of paper or insulating material consisting in
supporting the conductor upon a pair of rollers which are rotated by suitable
gearing whilst the conductor itself is also rotated and the sheets of insulating
material are lapped around it.
2. In machinery for covering electric conductors providing driving gear for
rotating the conductor, and other driving gear for rotating a roller or rollers in
contact with the conductor at approximately equal surface speeds as herein set
forth.
3. In machinery for covering electric conductors providing coned pulleys and
automatic belt shifting gear for maintaining approximately uniform surface speed
on the conductor being covered as herein set forth.
4. In jointing together lengths of electric mains such as shewn by the annexed
drawings and containing concentric conductors; the means herein described for
joining up the several lengths of conductors without the use of short connecting
pieces by adapting the ends to fit the one into the other and driving them forcibly
together.
5. In jointing together lengths of electric mains such as shewn by the annexed
drawings and provided with outer or protecting tubes; joining up the several
lengths of outer or protecting tubes without the use of short connecting pieces by
adapting the ends to fit the one into the other, driving them forcibly together and
then forming annular grooves around them where they overlap.
6. An electric main formed in the manner described in respect to Figure 4 with
in each length two metallic tubes fitted closely the one within the other and the
outer tube projecting at both ends beyond the inner end these projecting ends being
adapted so that the projecting end of one length fits into the projecting end of the
next length as herein set forth.
7. Jointing together lengths of electric mains substantially as herein described
and represented by the annexed drawings.

page_text: 8. The means herein described of building up an electric main having concentric
tubular conductors; by first clothing the lengths of the inner conductor with sheets
of paraffined paper or other insulating material lapped around them, then connecting
such lengths by forcing together the ends, then passing over the inner conductor so
jointed together, the lengths of the outer tube, and connecting these together
in the intervals between the joints of the inner conductor as herein set forth.
9. The means herein described of building up an electric main; by clothing
exteriorly a central tube or conductor with sheets of paraffined paper or other
insulating material, and by clothing interiorly another tube with like insulating
material and finally securing the former within the latter as herein set forth.
Dated this 0th day of May 1801
S. Z. DE FERRANTI.