Improvements in Insulators or Insulating Supports for Electric Conductors.
Year: 1891

page_text: Date of Application, 27th Oct., 1891
Complete Specification Left, 21st July, 1892-Accepted, 27th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in Insulators or Insulating Supports for Electric
Conductors.
A communication by ROBERT HEWETT, of Saint Louis, in the State of Missouri,
Electrician, and FRANKLIN LEONARD POPE, of Elizabeth, in the State of
New Jersey, Electrical Engineer, both of the United States of America.
I WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E. of the Agency for
Foreign Patent Solicitors 6, Lord Street, Liverpool and 6, Bank Street,
Manchester, both in the County of Lancaster, and 323 High Holborn, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this
invention to be as follows
The body of this improved insulating support is preferably made of porous
material. It may be held in a ring or collar of metal, fixed to a post or other
support. A cup or reservoir, situated within or near the body of the insulator,
serves to contain a supply of liquid non-conducting material, which is at the same
time repellent of moisture, such as resin or paraffin oil. Ducts or channels are
provided, either within or without the body of the insulator, from which the said
liquid percolates slowly, by capillary attraction, either through the porous
substance of the insulator, or through a wick or other like porous or capillary
device, flowing therefrom in a thin continuous film along the external surface, and
dripping off at the lower edge, thereby constantly keeping said film renewed with
fresh oily material, and carrying away any conducting particles which may have
found lodgment thereupon, and maintaining the surface as well as the body of
the insulator (when required) in such a condition as to effectually prevent the
escape of the electric current to the earth. The reservoir may be replenished
with fresh liquid from time to time as its contents becomes exhausted.
Dated thia 26th day of October 1891
WM. P. THOMPSON & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Insulators or Insulating Supports for Electric
Conductors.
A communication by ROBERT HEWETT, of Saint Louis, in the State of Missouri,
Electrician, and FRANKLIN LEONARD POPE, of Elizabeth, in the State of
New Jersey, Electrical Engineer, both of the United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool, and 6 Bank Street,
Manchester, both in the County of Lancaster, and 323 High Holborn in the
County of Middlesex, Civil Engineer, 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 :-
This invention consists in an improvement in the construction of insulators or
insulating supports for electric conductors. The body of the insulator is preferably
made wholly or in part of porous material. The insulator proper may be held in a
ring or collar of metal fixed to a post or other support. A cup or reservoir
situated within or near the body of the insulator serves to contain a supply of

page_text: liquid non-conducting material, which is, at the same time, repellent of moisture,
such as resin oil or paraffin oil. Ducts or channels are provided either within or
without the body of the insulator from which the said non-conducting liquid
percolates by capillary attraction through the porous substance of the insulator or
through other like porous or capillary device extending therefrom in a thin con-
tinuous film along the 'external non-conducting surface and dripping off at the lower
edge of the insulator, thereby constantly keeping said film renewed with fresh oily
material carrying away any conducting particles that may have found lodgment
thereupon and maintaining the surface as well as the body of the insulator in such
a condition as to effectually prevent the escape of the electric current from the
conductor to the earth. The reservoir may be replenished with fresh liquid from
time to time as its contents become exhausted.
Figures 1, 2, 3 and 4 of the accompanying sheet of drawings show vertical
transverse sections of various forms of insulators embodying the principle of the
invention.
Figure 5 is a plan view of the insulator shown in Figures 3 and 4.
Referring to Figure 1, the body of the insulator is shown at A and is preferably
made of wood, unglazed porcelain or earthenware, or other pervious or porous material,
the pores of which form capillary ducts. It may be cylindrical and slightly tapering
in form, and held and supported within a metallic ring or collar B, integral with a
shank D, which forms a support for the insulator, and is shown as provided with a
threaded end so that, by means of suitable nuts, it may be secured to the side of
a conduit H or other convenient support. The insulator A is made concave at its
upper end so as to form a cup or reservoir C for containing a supply of a suitable
liquid non-conducting material, which is, at the same time, repellent of moisture;
such, for example, as paraffin or resin oil. The conducting wire T may be sup-
ported by means of a clip or other suitable fastening upon the end of a hook or
wire-holder E, which may be secured centrally in the body of the insulator A, as
shown.
In an insulator of the form here shown, or of any of the forms in ordinary use,
the leakage or escape of electricity takes place over the surface of the body of the
insulator, from the wire-holder E to the ring B by reason of the accumulation of
moisture and dirt upon the surface which forms a conducting path for the current.
In order to keep this surface covered with a film of the liquid non-conducting
material, which shall be constantly renewed, channels II are formed within the
body of the insulator which are at all times filled with the liquid from the
reservoir C, which liquid percolates slowly through the pervious material of
the insulator, flows in a thin stratum along the external surface and drips off at the
lower edge, thereby keeping the film constantly renewed with fresh material and
carrying away any particles of dirt or conducting substance which may have found
a lodgment thereon, thus maintaining the surface as well as the body of the
insulator in a condition to effectually prevent the escape of the electric current
from the conductor T to the earth.
The reservoir C at the top of the insulator is preferably covered with a cap F,
whereby foreign substances are prevented from entering. It may be replenished
with fresh liquid from time to time as may he required.
In Figure 2, the body of the insulator A is composed of wood and has the usual
bell shape at the bottom, as shown at a. The upper part of the insulator is formed
into a reservoir C and is filled with insulating oil which saturates the entire porous
body of the insulator and continually exudes through the pores of the wood which
constitute capillary ducts into the crown of the bell a. The inclined shape of the
interior of said crown causes the oil to flow rapidly outward to the rim, and thence'
in a thin film down to the edge where it drips off. It is preferred to so arrange the
wood of which the insulator is formed that its pores will extend in a longitudinal
direction and not in a transverse direction; close-grained wood is the most suitable
for the purpose, and it is preferred to treat the wood by kiln-drying it before using,
so as to expel all volatile matter. The bolt E, which serves to sustain thei

page_text: conductor, is preferably screwed into the body of the insulator as shown, and may
be provided with a nute or other equivalent means for securing the conductor in
any convenient way.
Figure 3 is a sectional view and Figure 5 a plan of another form of the
insulator.
In this instance, the shell A of the outer portion consists of a tube of well glazed
porcelain, glass or vulcanite. A porous plug H of wood, unglazed earthenware or
other pervious material, is inserted in the lower part of the contracted portion of the
tube A and constitutes the bottom of the oil chamber CC o c. The plug H is held
upward against the beveled shoulder by means of the bolt E, which passes through
the plug and then through the perforated disc G, and is secured by the nut e¹.
The perforated disc G is sustained by a shoulder formed annularly within the
tube A as shown in the figure. The perforations 99 in this disc permit the non-
conducting oil to pass freely from the upper chamber C to the lower chamber c.
The oil percolates slowly through the porous plug H, passes over the insulating
surface and drips off at the edge of the bell as hereinbefore explained,
In Figure 4 is shown still another form of the insulator in which the pervious
portions are reduced to smaller dimensions. The bottom of the oil chamber C is
here shown as composed of a disc of non-porous material I, held in position by a
collar f formed upon the shank E which passes through its centre. A washer or
diaphragm of felt or other like material J is placed between the bevelled upper
surface of the washer I and a corresponding shoulder upon the interior of the
tube A. The parts are held in position as in the construction hereinbefore
described by the nut e'. It is preferred to place a second washer of felt K between
the collar fand its disc I. In this form of the insulator, by tightening or loosening
the nut e, the quantity of oil fed through the insulator may be regulated as
required.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondents I declare that what I claim is :-
1. The improvements, substantially as hereinbefore described, in insulators or
insulating supports for electric conductors, for preserving the non-conducting
properties of such insulators or insulating supports, which consist in coating the
exterior surface of the body of such insulators or insulating supports with a film
of non-conducting liquid and automatically maintaining a constant supply of said
liquid, whereby said film is continually renewed.
2. An insulator for supporting electric conductors containing a receptacle or
reservoir of non-conducting liquid and capillary ducts for automatically conveying
a continuous supply of said liquid from said reservoir to the non-conducting
surface of said insulator, substantially as hereinbefore described.
3. In an insulator for electric conductors, the combination of the non-conducting
body, the wire holder, the reservoir and the ducts leading from the reservoir to the
insulating surface, substantially as hereinbefore described.
T
11 oth 3 T_1_ 1800
WM. P. THOMPSON & Co.,
Agents for the Applicant.