Improvements in Joints for Electric Mains.
Year: 1888

page_text: Date of Application, 30th Aug., 1888
Complete Specification Left, 30th May, 1889-Accepted. 6th July, 1889
Improvements in Joints for Electric Mains.
1. 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:-
This invention has for its object improvements in joints for electric mains.
The mains which I employ for the conveyance of high tension currents consist of
concentric copper tubes separated by a lapping of paraffined paper; the outer tube is
drawn down upon this insulating material and made to embrace it tightly.
In connecting these mains expansion joints have to be introduced at intervals and
these prepare in the following manner-the outer tubular conductor is cut away
for a distance of some inches from the end of each of the lengths to be joined and in
its place a cylinder or ferrule of vulcanite is substituted. But before this is done two
metal rings fitting pretty accurately are passed on to the outer conductor of length
and so also is a cylindrical piece of vulcanite; this at its inner end is thickened to fit.
the corresponding end of the vulcanite ring or ferrule.
There is also a third cylinder of vulcanite which is passed on to one of the ends; it
is longer than the others and of a size to enter freely between them.
There is still another part which has to be passed along one of the lengths before
the operation of making the joint is commenced; this is a metal tube into which
the metal rings previously mentioned will just enter. This tube is corrugated around
its central part to give to it the capacity to elongate and contract to the extent
required. In making the joint cones of copper are screwed into the ends of the inner
conductors which have previously been prepared to receive them.
These cones have flanges and into holes in the flanges strands of copper wire have
been fixed with solder. These strands are -ufficiently flexible to permit of the expansion
and contraction which it is necessary to provide for.
The tubes of vulcanite are now brought together and on each length joints are
made by means of india rubber cement between the outer and inner tubes where they
fit together.
The longer middle tube of vulcanite is now loosely held between the other rings
but so as to allow the requisite play. The external corrugated tube is.now brought
over the joint and the metal rings are inserted into its ends. Thus each end of the
corrugated tube, in the plain part beyond the corrugations, now contains two metal
rings with a space between. This space is intended to receive solder or white metal.
There are holes in the side of the corrugated tube for this metal to be poured in.
The parts with which the molten metal will come into contact have been previously
tinned viz. the external conductor, the metal rings and the corrugated tube so that
the solder or white metal connects these parts securely together. It will be seen
that the vulcanite rings or screens serve to interpose a sufficient obstacle between the
inner and the outer conductor to prevent the formation of an arc.
I use solder or white metal in like manner in making joints where no provision for
expansion is required. Then in place of providing vulcanite screens I completely fill
the cavity within the connecting tube or socket with paraffin or other suitable
insulating material or sometimes 1 make the socket with a lining of vulcanite. I
then cut back the outer conductor for a suitable distance from the ends so that the
ining of vulcanite (which is slightly tapered) may jain tight upon and around the
covering of paraffined paper. The inner conductors are coupled with a double cono
piece screwed into them with right and left threads. This double cone is flanged and

page_text: by the flange it is connected with the socket through the vulcanite, or the double cone
may be separate from the socket and its lining.
"
The socket may in some cases be screwed on to the exterior conductor.
n: 20 tv of 1000
CARPMAEL & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in Joints for Electric Mains.
I, 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:—
The object of this invention is mainly to provide a flexible expansion joint for
coupling together lengths of electrical conductors composed of two concentric tubes
separated from one another by insulating material.
I make the joint in the following manner. I insert into the ends of the inner
conductors copper cones which are connected by flexible conducting strands and I
connect the outer conductors by a metallic tube corrugated transversely.
To prevent an are being formed between the coupling which unites the inner
conductors and the corrugated tube which unites the outer conductors a tubular
telescopic or expansible screen is interposed between them.
The drawings annexed shew a joint formed according to my invention.
Figure 1 is a longitudinal section and Figure 2 a transverse section of the joint.
Figure 3 is a section through one of the lengths of the concentric tubular conductors
which the joint connects.
$
a is the inner tubular conductor of copper, is the outer tubular conductor
preferably of the same metal. c is the insulating material between the two. ff are
hollow cones or plugs of copper screwed into the conductors a a and.g g are flexible
wire strands soldered to them.
is a copper tube the central portion of which is
corrugated transversely as shewn. are rings fitting into its plain ends and fitting
over the outer tubular conductors b. These rings enclose between them a cavity for
white metal to be poured into. When white metal is poured in, the tubes 6 and h
and the rings i and become soldered together.
I is a
The outer tube b of the portion of the concentric tubular conductor which projects
beyond the ring is cut away and a tube k of vulcanite or like insulating material
put in its place this tube is made to closely embrace the insulating material c.
tube of vulcanite fitting loosely over the tubes k and m m are outer tubes of vulcanite
thickened at one end and made to fit upon the tubes where these also are slightly
thickened. India rubber varnish may be filled into the space between the tubes k
and m.
To make one of the joints, the outer tubular conductor is first cut away for a
distance from the end of each of the lengths which are to be joined.
The metal rings i are slipped on to the outer conductors and the vulcanite tubes k
are fixed in place-the vulcanite tubes m are slipped on to the outer metallic tubes b
of the two lengths-and also the vulcanite tube on to one of the lengths. The
corrugated tube 7 is also slipped over the end of one of the lengths.
The cones of copper are now screwed into the ends of the inner conductors which
have previously been prepared to receive them.
These cones have flanges extending around their outer ends and in these are holes
for the ends of the copper strands to be passed into.
When the ends of the strands
have been inserted into the holes they are fixed therein by solder. The vulcanite
tubes in and are now slipped into their proper places the joints between the vulcanite
tubes mand k being made tight by india rubber cement.

page_text: The rings and the corrugated tube h are now slipped into their proper places.
When this has been done white metal or solder is poured into the spaces between
The parts
the rings i, i, through holes formed for the purpose through the tube h.
with which the molten metal comes into contact having been all previously tinned these
parts become securely soldered together and the joint is complete.
I in like manner use solder or white metal in making joints where no provision for
expansion is required. Then in place of providing vulcanite screens I completely fill
the cavity within the connecting tube or socket with paraffin or other suitable
insulating material or sometimes I make the socket with a lining of vulcanite. 1
then cut back the outer conductor for a suitable distance from the ends so that the
lining of vulcanite (which is slightly tapered) may jam tight upon and around the
covering of paraffined paper. The inner conductors are coupled with a double cone
piece screwed into them with right and left threads. This double cone may be
flanged and by the flange be connected with the socket through the vulcanite, or the
double cone may be separate from the socket and its lining.
The socket may in some cases be screwed on to the exterior conductor.
Examples of joints formed in these ways are shewn at Figures 4, 5 and 6. In
these figures the parts marked a are of copper, & is insulation, c white metal, d wax
and e ebonite.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is :-
=-
1. A flexible or expansion joint for electric conductors in which the conductor is
surrounded by a telescopic insulator.
2. A flexible or expansion joint for electric conductors in which the conductor is
surrounded by a telescopic insulator itself surrounded by a corrugated metal tube
which excludes access of water and is capable of increase or decrease in length.
3. A flexible or expansion joint for electric conductors formed of a metal tube
corrugated transversely and secured at one end to the end of one length of conductor
and at the other end to the next length.
4. A joint connecting the ends of two lengths of an electric conductor composed
of two rings surrounding each length near its end at a distance apart from one
another and of a metallic tube surrounding the rings on both lengths and of readily
fusible metal filling the spaces between the two rings on each length.
5. The combination of two rigid tubular conductors or rods coupled end to end by
flexible copper strands and surrounded by other tubular conductors separated from
them by insulating material.
6. The combination of the inner conductors a coupled by cones or plugs and
flexible conducting strands g the outer concentric conductors 6 coupled by an
extensible tube and the insulating screens k l m interposed between the extensible
tube and the cones f and strands g.
201 1
CAL 1000
S. Z. DE FERRANTI.