Improvements in and relating to Insulators for Electrical Purposes.
Year: 1895

page_text: Date of Application, 13th June, 1895
Complete Specification Left, 28th Nov., 1895-Accepted, 28th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in and relating to Insulators for Electrical
Purposes.
We, ALFRED JAMES PERTON WHITAKER of Llanishen, near Cardiff, Chartered
Accountant and FREDERICK GWILYM TREHARNE Analytical Chemist of Wrang-
brook, Llanishen near Cardiff in the County of Glamorgan, do hereby declare the
nature of this invention to be as follows:-
Our invention relates to improved insulators for electrical purposes and chiefly
,for telegraph and telephone wires.
According to our invention we form insulators of steel or other metal and we
coat them with a non-conducting enamel composed chiefly of silica and aluminium
together with, in the preferred form, a more or less relatively small quantity of
lime, barium, tin and borax.
The composition of the enamel may, for example, be as follows:-
Silica
Aluminium
Lime
Barium
Oxide of tin
Borax
-
50 per cent.
-
20
do.
-
5
do.
-
5
do.
5
do.
15
do.
100
do.
We preferably carry our improved insulator by a spindle or spike which may
be coated with the non-conducting enamel aforesaid. The spindle is held in
position in the insulator and is insulated therefrom by means of a substance
composed of sulphur, bitumen, sulphate of lime, sulphate of barium, silica, together
with in some cases oxide of lead and resin, which substances may, for example, be
advantageously combined in the following proportions
Sulphur
-
:-
20 per cent.
The said composition is preferably placed in a recess in the insulator when in
a plastic state the spindle being then held in position therein till the composition
sets" and hardens.
Our improved insulators are adapted for use in any climate.

page_text: Improvements in and relating to Insulators for Electrical
Purposes.
We, ALFRED JAMES PERTON WHITAKER, of Llanishen, near Cardiff, in the
County of Glamorgan, Chartered Accountant and FREDERICK GWILYM
TREHARNE, Analytical Chemist, of Wrangbrook, Llanishen near Cardiff afore-
said, 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 improved insulators for electrical purposes and chiefly
to insulators for telegraph and telephone wires. Our improved insulators are
however well adapted for carrying conductors intended for high voltage currents
and also as insulating supports for accumulators and other electrical apparatus.
Our improved insulator consists of a steel or other metal shell filled with a
suitable insulating cement or composition, and coated with a suitable non-conducting
enamel composed chiefly of silica and aluminium or of resinous gums suitably
prepared, and having in some instances a spike or spindle for supporting the
shell.
We preferably carry our improved insulator by a spindle which may be coated
with the non-conducting enamel aforesaid, and which is held in position in the shell
and insulated therefrom by means of the above-mentioned cement or composition.
Referring to the accompanying drawings,
Figure 1 is a side elevation of an insulator constructed according to our invention,
and
Figure 2 is a central longitudinal section of the same.
Figure 3 is an elevation partly in section of a modified form of insulator.
Figure 4 is a similar view of a further modification the spindle being removed.
Figure 5 is a central longitudinal section on a smaller scale of a still further
modified form of insulator furnished with two shells separated by insulating
cement.
Figure 6 is a similar central section of a further modified form of insulator
constructed according to our invention, and
Figure 7 is a similar section of an insulator suitable for supporting accumulators.
Like letters of reference denote corresponding parts in the several figures.
A is the metal shell or body of the insulator which may have any desired shape;
B is the spindle; C is the insulating cement or composition which fills the shell A
and receives and retains the spindle B; D is the non-conducting enamel coating
which is composed chiefly of silica and aluminium together with a more or less
relatively small quantity of lime, barium, oxide of tin and borax. The composition
of the enamel may, for example, be as follows :-
Silica
fiftv
(50) nor cont.

page_text: The insulating cement C is composed of sulphur, bitumen; sulphate of lime or¹
sulphate of barium, and silica, with, in some cases, oxide of lead or resin, or oxide
of lead and resin which substances may, for example, be advantageously combined
in the following proportions :-
"
The said insulating cement is placed in the shell A while in a plastic state, and
the spindle B is then held in position therein till the cement or composition "sets
and hardens. The spindle may be arranged to pass right through the insulator as
in the form shown in Figures 3 and 4 or it may only project into the interior of
the insulator, as shown in Figure 2. In either case the spindle is secured to and
insulated from the shell A by means of the insulating cement C.
The insulator shown in Figure 5 is furnished with a second metal shell E enclosing
the shell A and secured thereto by insulating cement C at the upper or inner end.
An annular space F unfilled with cement is left between the two shells as shown, to
diminish the risk of leakage when the insulator is exposed to driving rain. The
shell E is coated with enamel. In Figure 6 a metal cylinder G is shown
surrounding the spindle B and embedded in the cement. Another cylinder H of
larger diameter than the cylinder G is also shown embedded in the cement. This
cylinder may be made of enamelled iron or of woven natural or manufactured
silicates of iron or aluminium. Two or more such cylinders may be used in one
insulator. The cylinders may be coated with the above described enamel.
In Figure 7 we have shown an insulator suitable for supporting accumulators.
It consists of an inner metal tube J, an outer metal shell A having a flat top, and
insulating cement C between the shell and tube. The tube projects from the outer
shell and serves as the foot of the insulator. This form of insulator will be very
useful in connection with electric tramways and railways. The shell or shells is or
are preferably lined internally as well as coated externally with the enamel.
some instances however the enamel coating may be omitted.
In
Our improved insulators are adapted for use in any climate, they are very
cheap, and are much more durable than porcelain insulators, being practically
unbreakable.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. An improved insulator for electrical purposes consisting of a metal shell
coated with the non-conducting enamel, in coinbination with a spindle for carrying
the insulator, and the insulating cement for securing the said spindle within the
shell, substantially as described.
2. The non-conducting enamel composed of silica, aluminium, lime, barium,
oxide of tin and borax, substantially in the proportions, and for the purpose,
specified.
3. The insulating cement composed of sulphur, bitumen, sulphate of lime, or
sulphate of barium, silica and oxide of lead, or resin, substantially in the proportions,
nd for the purpose, specified.
4. The modification of our improved insulator wherein we provide two metal
shells or an
outer metal shell and an inuer tube or two or more inner tubes
connected by insulating cement and each coated with non-conducting enamel,

page_text: substantially as described with reference to Figure 5, or to Figure 6 or to Figure 7
of the drawings.
Dated this 28th day of November 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicants.