Improvements in Insulating and Supporting Electric Conductors.
Year: 1898

page_text: Date of Application, 18th Nov., 1998-Accepted, 29th Apr., 1899
CUBE DELE
Improvements in Insulating and Supporting Electric Conductors.
I, LOUIS HACKETHAL, of No. 2, Ernst August Platz, Hanover, in the German
Empire, Telegraph Superintendent, 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 the present application consists of, a novel means of insulation for
electrical constructions of all kinds, which is devised to be applied in combination
with a process for the laying of above ground electrical conductors for telephone
purposes. The insulation can by way of example serve to protect the insulation of
above ground conductors, whether of weak or of strong current against the
influence of the weather, to obviate short circuits and the like, and to protect the
weak current lines against the injurious influence of strong current
lines in the case of contact, besides which by means of the arrange-
ment of the conductors according to my system the inductional influences are also
entirely obviated. It is well known that from all conductors traversed by strong
currents or weak currents there radiate magnetic lines of force in concentric circles,
the influence whereof diminishes as the radius of the circle increases. These
radiating lines of force prolong themselves from the conductor in a direction
at right angles to the direction of the current, and are capable of creating electric
currents in neighbouring conductors. It is further well known that these influences
are less in the case of metallic return circuit conductors than in the case of single
lines with earth return, and moreover in the proportion of the differential action
which results from the influences. From this it follows that if a position be given
to the metallic outgoing and return conductors, such that both of them are inter-
sected by the magnetic lines of force of neighbouring conductors in like directions,
and at like distances, the influences will neutralize one another completely, 80
that such metallic outgoing and return conductors will be protected against all
influences from adjacent conductors. This condition is fulfilled by the construction
of metallic outgoing and return conductors hereinafter set forth. At the present
time above ground telephone conductors are constructed exclusively of naked wire
either arranged as a single line or in the so-called group conductors. In the latter
kind there are used two insulators at each points of support. In view of the danger
of these wires touching one another or other wires, the distance between them, both
In the horizontal as also in the vertical direction is made somewhat considerable.
Nevertheless, such interruptions, and contacts with other conducting bodies happen
daily. Both conductors are moreover at unequal distances from other conducting
bodies, and are therefore liable to be influenced unequally by induction from these
latter, so that both the conversation, telegraph, and strong currents from other
connections act upon them, and disturb their operation. The removal of this,
and of other drawbacks can be effected according to my process by the construction
of a telephone connection formed of an outward and return conductor in the shape
of insulated wires, and as shewn in the accompanying drawing with the application
of only one insulator at each point of support, the conductors being so attached
to the insulators that each of the two wires is alternately placed at the front and

page_text: hinder end of the insulator. In this manner the two wires of the same conductor
are brought so near together, and are so equally disposed with regard to their
distances from other conductors, that the inductive action of the latter will be
exercised equally upon both wires, and will consequently be entirely neutralized
thereby. For transmission wires with the insulation hereinafter described should
be used. The composition and construction of the insulators for these wires is so
devised, that the conductors are prepared with a wrapping of textile fabric woven
upon them, or wrapped spirally around them, which fabric has been dipped into an
emulsion of red lead or litharge and linseed oil, and exposed to the air until the
preparation is thoroughly hardened. The dry litharge consists of finely powdered
oxide of lead which is dielectric in a high degree. These are so intimately com-
bined in the proportions of 4 to 5 parts by weight of oxide to 1 part of oil that
the oil with the oxide is able to penetrate and fill the finest pores of the fabric in the
same manner as pure oil would do. On account of this latter property litharge
has proved itself to be the most suitable means of rendering tight connections
which are subjected even to high pressure, such as air, gas, steam, or water
tubes; also in ceramics, in the manufacture of accumulators, and for other
industrial purposes, and for the protection of metallic objects against oxidation
litharge has become of special importance.
Experiments have proved that the hard crust produced by the combination of the
indiarubber-like constituents of the linseed oil in combination with the dielectrical
lead oxides possesses a high degree of insulating capacity, and is not influenced by
changes of temperature, burns with only a little flame, and does not become
brittle, crumbly, nor decomposed; it is impervious, and is non-absorptive to
moisture, and is therefore specially adapted in combination with fabrics to protect
articles against the influence of the weather, and the insulation of the wires
protected by it is maintained almost in undiminished strength. Moreover, in
the above described method of preparing the insulating wrapper there is formed
upon the wire itself a skin-like covering of lead oxide, which hardens to a great
firmness, and which remains unaltered for a considerable number of years (as
has been proved by the examination of old pieces of iron painted with lead oxides)
as long as it is not exposed directly to the action of the weather. This protection
is given in addition to its dielectric properties to the fabrics soaked in the
material, which fabrics prove themselves to be very resistant to corrosion, and to
be as little alterable under the influence of great heat or cold as the litharge
covering itself of the wire. The insulation resistance of the litharge in the
hardened condition, or after combination of the oily parts with the highly
oxidized material of the litharge exceeds that of other usually employed insulating
materials very considerably, and may amount to from 80 to 100,000 megohms
and more per cubic centimeter, the exact amount depending upon the amount of
the absorption, and the state of the oxidation.
Only such wires as have been treated with the above described insulating
material, and arranged according to the process herein set forth will give the
advantages indicated.
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 metallic outward and return conductor for telephone purposes characterized
by the use of one insulator only for each point of support, in such a manuer that
the single conductors fixed at both sides of the head of the insulator, and
moreover specially insulated, are carried in the same plane, and in regular
alternation across one another.
2. In the metallic outward and return conductor for telephone purposes as
set forth in Claim 1, the special insulating material for the conductors consisting
essentially of a wrapper of thin fabric, or of a band formed from the said fabric,
soaked in an emulsion of litharge and linseed oil, together with the application

page_text: of liquid lead paint for the purpose of protecting electric current conductors of
every kind against the loss of current or interchange thereof, both in cases in which
the lead oxides are materially attached to the objects to be insulated, or are
applied in any manner in combination with auxiliary materials.
[898.
W. P. THOMPSON & Com
322, High Holborn, London, W.C.,
Patent Agents for the Applicant.