Improvements in Conduits for Electrical Conductors.
Year: 1892

page_text: Date of Application, 26th Oct., 1892
Complete Specification Left. 25th July, 1893-Accepted, 30th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Conduits for Electrical Conductors.
We, CHARLES EDMUND WEBBER, C.B., Major General, Royal Engineers,
retired, of 17, Egerton Gardens, Kensington, in the County of London, JOHN
SMITH RAWORTH, Engineer, of 112, Belvedere Road, Lambeth in the County of
Surrey and THOMAS OCTAVIUS CALLENDER, Engineer, of 101, Leadenhall Street
in the City of London, do hereby declare the nature of this invention to be as
follows:-
<<
Our invention relates to certain improvements in conduits for conductors of
electrical energy, and has for its objects to provide a "way" or ways therein so
perfectly insulated that naked low or high pressure conductors (as defined by the
regulations prescribed by the Board of Trade under the provisions of the Electric
Lighting Act, 1888) can be used, and whereby it is unimportant whether the
substance of which the conduit itself is formed, or the material used for jointing
the sections of the same are good non-conductors of electricity or not.
In 1884 Charles Edmund Webber one of the present inventors and another
proposed in Patent No. 3,318 a method of laying naked electrical conductors in a
stretched condition inside troughs, in which they were supported by spacers of
insulating material and were also embedded in paraffin with which the troughs were
filled after the conductors had been fixed in position.
And later in 1886, under Patent No. 10,393, the said Charles Edmund Webber
and T. O. Callender secured the construction of conduits, ways, or cases for
electrical conductors, cables, &c., with a separate way therein for each conductor
or cable, and they intimated that such conduits or cases might be preferably made
of one of the mastic materials described in the Provisional Specification No. 1,538
of 1886 of J. W. Butler.
In 1891, in Patent No. 3,239, we proposed the use of paper tubes for the
electrical conductors having insulated supports all laid in metal cases with
removable covers and embedded in bitumen or bitumen compound.
In the first of the above named inventions the patentees found that shrinkage of
the embedding material was the cause of electrical leakage.
In the second case it was found that the porosity of the mastic material itself,
and the difficulty of making insulating joints precluded the use of naked conductors.
In the third case we found that the surrounding or embedding material of the
paper tubes having to be filled in in a melted state at the time of laying incurred a
wasteful expenditure of labour.
In carrying out the present invention we make our insulated ways for the
conductors of electricity of tubes of paper, paper compound or other substance
having equivalent or nearly equivalent properties of insulation resistance. These
tubes are made with spigot and faucet ends or otherwise in such manner that they
can be jointed longitudinally by insertions one into the other. They are inserted
into the way or ways of a conduit or casing which may be made of earthenware,
mastic compound, or any other suitable material, preferably of low electrical con-
ductivity, and sheathed or not with iron. It is an important feature of our
invention that in the jointing of these tubes, the joints thereof are invariably
arranged to break joint with the joints of the sections of the containing conduit or
casing.
Before insertion the paper tubes are treated with paraffin or other suitable
composition to ensure tight joints, and so as to fill interstices and to secure, as far

page_text: as possible, the required degree of non-porosity, and thus the insulating "way" or
"ways is or are continuous and perfect.
::
Dated his 50th of October 1800
J. C. CHAPMAN,
Agent.
COMPLETE SPECIFICATION.
Improvements in Conduits for Electrical Conductors.
We, CHARLES EDMUND WEBBER, C.B., Major General, Royal Engineers,
retired, of 17, Egerton Gardens, Kensington, in the County of London, JOHN
SMITH RAWORTH, Engineer, of 112, Belvedere Road, Lambeth, in the County of
Surrey, and THOMAS OCTAVIUS CALLENDER, Engineer, of 101, Leadenhall Street,
in the City of London, 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:-
"
Our invention relates to certain improvements in conduits for conductors of
electrical energy and has for its objects to provide a way" or ways" therein so
perfectly insulated that naked low or high pressure conductors (as defined by the
regulations prescribed by the Board of Trade under the provisions of the Electric
Lighting Act, 1888) can be used, and whereby it is unimportant whether the
substance of which the conduit itself is formed or the material used for jointing the
sections of same are good non-conductors of electricity.
In 1884, C. E. Webber, one of the present inventors and another proposed in
Patent No. 3318 a method of laying naked electrical conductors in a stretched
condition inside troughs in which they were supported by spacers of insulating
material and were also embedded in paraffin with which the troughs were filled
after the conductors had been fixed in position.
And later in 1886, under Patent No. 10393, C. E. Webber and T. O. Callender,
two of the present inventors, secured the construction of conduits, ways, or cases
for electrical conductors, cables, &c., with a separate way therein for each con-
ductor or cable, and they intimated that such conduits or cases might be preferably
made of one of the mastic materials described in the Provisional Specification
No. 1538 of 1886 of J. W. Butler.
In 1891, in Patent No. 3239, we proposed the use of paper tubes for the
electrical conductors having insulated supports all laid in metal cases with
removable covers and embedded in bitumen or bitumen compound.
In the first of the above-named inventions the patentees found that shrinkage of
the embedding material was the cause of electrical leakage.
In the second case it was found that the lowest specific insulation of the mastic
material itself, and the difficulty of making perfectly insulating joints precluded the
use of naked conductors.
In the third case we found that the surrounding or embedding material of the
paper tubes having to be filled in in a melted state at the time of laying incurred a
wasteful expenditure of labour.
In carrying out the present invention we make our insulated ways for the
conductors of electricity of tubes of paper, paper compound, or other substance
having equivalent or nearly equivalent properties of insulation resistance. These
tubes are made with spigot and faucet ends or otherwise in such manner that they
can be jointed longitudinally by insertion one into the other. They are inserted
into the way or ways of a conduit or casing which may be made of earthenware,
mastic compound or any other suitable material preferably of low electrical con-
ductivity and sheathed or not with iron. It is an important feature of our invention
that in the jointing of these tubes the joints thereof are invariably arranged to
break joint with the joints of the containing conduit or casing.
Before insertion the paper tubes are treated wholly or partly, but preferably
wholly, with paraffin or other suitable composition to ensure tight joints and so as

page_text: to fill interstices and to secure as far as possible the required degree of non-porosity
and insulation, and thus the insulating way' or 'ways' is or are continuous and
perfect.
In further explanation we have illustrated our invention in the annexed drawing
which forms part of this Specification.
Fig. 1 is an isometrical perspective view of a three-way conduit or casing having
two of our improved ways for the conductors inserted thereinto.
Fig. 2 is a longitudinal section of same showing two ways in elevation.
P are our improved tubular insulated ways each tube of which is double or about
double the length of the casing C, and of practically the same outer diameter as
the case-way.
Each tube P is tapered at one end p as shown, or it may be
shouldered or otherwise fixed so as to admit of its being jointed longitudinally by
insertion into the faucet or cylindrical end of the next one, and so to make a
continuous tube. The casing C is shown sheathed with iron c for protection.
By the arrangement above described it follows that all the joints of the tubes P
break with those of the casings C as illustrated. The insertion of the tubes P
into the casings C is preferably performed during the laying and setting in per-
manent position of each casing by passing each subsequently laid casing of the line
over the projecting tubes P of the last one. To ensure a good fit between casings
and tubes and also at the joints of casings bitumen or suitable mastic may be
employed, though it is not essential.
We would observe that an important advantage incidentally accrues from our
above described invention, viz. that it enables the localisation between any two
points in a line of conduits of a leakage from the copper to earth through the
conduit after the conductor has been drawn in, to become a simple matter. This
may be readily done in the following manner. First, cut the copper conductor at
any two points between which leakage is suspected and provide by suitable insula-
tion against its making earth' outside the conduit. Then connect it up with a
testing battery through a detector, taking care to leave sufficient slack insulated
leads to an earth.' Next draw the defective conductor slowly out of its 'way'
maintaining the insulation from earth of the portion withdrawn. When the fault
is reached and passed the circuit will be interrupted and this will be shown by a
reduction of the pressure indicated by the detector. Then accurate localisation is
'
merely a matter of measurement as will be readily understood.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
6
1. In conduits for electrical conductors making the way' for each conductor of
tubes of paper or equivalent as specified such as P, adapted to be jointed longi-
tudinally by insertions one into the other, and inserting same into the 'way' of a
conduit or casing such as C and so as to break joint therewith as shown whereby
each way is continuous and so perfectly insulated that naked copper conductors
can be used for high or low pressure without electrical leakage as above set
forth.
2. In conduits for electrical conductors the use of continuous spigotted or
longitudinally jointed tubes of paper or equivalent as specified inserted into the
ways of casings sheathed or not with iron, and arranged so as to break joint and
form a continuous and perfectly insulated way for each naked copper conductor
substantially as hereinbefore described and illustrated.
Dated this 25th day of July 1893.
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