Improvements in Insulators.
Year: 1890

page_text: Date of Application, 29th Nov., 1890-Accepted, 21st Feb., 1891
Improvements in Insulators.
I, JAMES FERGUSON MUNSIE, of 337, Broadway, in the City of Brooklyn,
County of Kings, State of New York, United States of America, 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 invention relates to certain new and useful improvements in insulating devices
for underground or overhead conductors for electric railways, and has for its object
to so construct and arrange the insulating device and its accessories as to
maintain a portion of said insulating device intermediate of the point of connec-
tion of the conductor and the point of support of the insulator, constantly in a dry
condition, for the purpose of preventing any possible grounding of the current in
wet weather; the said dry portion serving as a complete insulating break between
the conductor and the ground.
In carrying out my invention, I have devised the construction and arrangement
of parts illustrated in the accompanying drawings, wherein
Figure 1 represents a longitudinal section and partial elevation of an under-
ground electric railway conduit provided with my improvements, the section being
taken on a plane indicated by the line 1-1 of Figure 2.
Figure 2 represents a vertical cross-section thereof taken on the plane indicated
by the line 2-2 of Figure 1.
Figure 3 represents on an enlarged scale a side elevation of one of the insulators
employed in said conduit; and
Figure 4 represents in section a modified form of insulator, particularly designed
for overhead conductors.
Similar numerals of reference indicate similar parts throughout the several
views.
Referring to the drawing, 5 indicates an electric conduit provided with the
usual longitudinal slot 6 for the passage of the trolley-hanger 7, and having suitable
provision for carrying off to the sewer any dripping or condensation of water that
may accumulate at the bottom of the conduit; a convenient device for this purpose
is indicated by the outlet pipe 8 leading to the sewer and provided with a drip or
seal 9 to prevent inflow of sewer gases.
The positive and negative conductors are located respectively at opposite sides of
the conduit and consist of sections of conducting metal, supported upon the top of my
improved insulating devices. The metallic conducting sections 10 referred to are
electrically connected to form a continuous conductor (negative or positive) by means
of connecting pieces 11 of wrought iron, so as to make a substantial joint of low
resistance. I prefer to employ wrought iron as the material of construction of the
connecting piece 11, for the reason that it will not be subject from any cause to
permanent magnetization, which would tend to increase its resistance.
In the form of my insulator illustrated in Figs. 1, 2 and 3, I have shown the same
as consisting of a base 12 and a cap-piece 13, which may conveniently be formed of
wood saturated with oil, or of glass, glazed terra-cotta, or other equivalent material,
the two parts being joined by means of dowel-pins 14 or the like. The base 12 is
provided about its sides with a continuous annular groove as shown, and on its
upper surface with an annular depression 15, adapted to receive a hygroscopic
solid or liquid, as for instance calcic oxide, desiccated calcic chloride, sulphuric
acid, glycerine or similar material having an affinity for water.
The cap-piece 13 has an overhanging flange 16 extending from the upper edge or
rim of the base 12, so as to direct any water or drippings to the bottom of the

page_text: conduit. Each base-piece is provided with an aperture or perforation 17
extending entirely through it, and the said perforations are connected throughout
by means of intermediate pipe sections 18 having non-conducting jackets or coverings,
and adapted to receive and transmit to the insulating bases a heating fluid or liquid
such as hot-air, steam, hot-water, or the like, for the purpose of raising the
temperature of said bases, so as to drive off moisture therefrom or from the calcic
oxide or calcic chloride employed ordinarily as the drying agent, so as to renew or
revivify said calcic oxide or calcic chloride as drying agents.
In the form of my invention shown in Figure 4, the cap-piece 19 will form the
point of support, and the conductor sections 10 will be connected to the under side
of the base 20, the base and cap-piece being preferably connected by means of a
through-bolt 21. The depression or cavity illustrated in the upper part of the
piece 20 is for the reception of the hygroscopic material hereinbefore referred to.
The operation of my invention is as follows:
In the form illustrated in Figs. 1, and 3 any drippings of water that may take
place from the walls of the conduit or through the hanger slot upon the upper
surface of the cap-piece 13 are directed to the bottom of the conduit, the depression
in the top of the base-piece 12 being protected from said drippings by reason of the
overhanging flange of the cap-piece. Any water that may splash against the
bottom of the conduit is prevented from entering said depression by reason of
the curved form of the sides of the base, which is almost if not a complete pro-
tection against access of water due to splashing. If however any drops of water
should splash into the cavity or depression in the top of the base-piece 12, or should
any condensation of water upon the under surface of the cap-piece have a tendency
to form, such water or condensation will immediately be absorbed by the hygro-
scopic material within said depression, and as a consequence the lower surface of
the cap-piece will remain constantly in a dry condition. This dry portion of the
insulator is thus constantly interposed between the conductor and the ground,
thereby preserving at all times a reliable insulation, unaffected by drippings or
splashings of water upon the top of the insulator or about its sides. If at any time
it is desired to revivify the hygroscopic material by driving off its moisture, this
purpose can be readily effected by introducing a heating agent through the system
of pipes 18, as hereinbefore described.
In some instances I contemplate dispensing with the hygroscopic material and
employing the heating agent alone for maintaining the insulating base in a dry
condition; but the best results will be obtained by the employment of the two
conjointly.
In the form of my invention shown in Figure 4, the general mode of operation
and the results attained are similar to those just described, with the exception that
no provision is made for heating the insulator.
It will be evident that the insulators may be heated by other means than the
pipe system shown, and I do not therefore restrict myself to that particular means
of heating.
When I employ sulphuric acid as the hygroscopic material, I provide the cavity
or depression in the upper part of the base 12 or 20 with a lining of acid resisting
character, 22, such as sheet lead or stearic pitch.
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 I
claim is :-
1. An insulator of the kind described consisting of a base and an overhanging
cap-piece, said base being provided at its upper surface with a filling of hygroscopic
material; substantially as described.
2. An insulator of the kind described provided with a base, an overhanging cap-
piece, and means substantially as described for heating said insulator; substantially
as described.
3. An insulator of the kind described consisting of a base having a depression or

page_text: cavity in its upper surface for the reception of a hygroscopic material and an
opening for the reception of a heating agent, and an overhanging cap-piece; sub-
stantially as described.
4. An insulator of the kind described consisting of a base and an overhanging
cap-piece said base being provided with a flange or extension at its upper rim
to prevent splashing upon the under side of the cap-piece; substantially as
described.
5. An insulating system for electrical conductors consisting of a series of
insulators having perforations or channels for the reception of a heating agent and
pipe sections connecting said channels; substantially as described.
6. An insulating system for electrical conductors consisting of a series of
insulators having perforations or channels for the reception of a heating agent and
pipe sections connecting said channels, said pipe sections having non-conducting
jackets; substantially as described.
7. The combination with an insulator of the conductor sections 10 and connecting
joint 11 of wrought iron; substantially as described.
Dated this 20th dow of Novemba 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.