Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CABLE FLUID INJECTION SLEEVE
The subject application is a continuation-in-part of U.S. patent application
Serial No. 08/799,547 filed February 13, 1997 and entitled CABLE CONNECTOR
WITH FLUID INJECTION POINT.
Field of the Invention
The invention relates to electrical cable connectors, such as splices; and
further relates to conduits, or the like, for injection of fluid into the
interior of
electrical cables.
Background of the Invention
Beginning in the post-war construction boom of the late 1950s and
early 1960s, overhead electrical cable lines were recognized as an eyesore.
Underground electrical cable technology was developed and implemented due to
its
aesthetic advantages and reliability. Underground electrical cable, a medium
voltage
cable that carries from 5,000 volts to 35,000 volts with an average voltage of
15,000
volts, initially employed high molecular weight polyethylene (HMWPE) polymer
as
the insulation of choice due to its low cost and ease of manufacturing.
Subsequently,
cross-linked polyethylene (XLPE) and ethylene propylene rubber (EPR) replaced
high molecular weight polyethylene as the insulation. More recently, a water
damage retardant formulation has also been included in these newer types of
insulation.
Underground electrical cable was initially touted as having a useful life of
from 25 to 40 years. However, the useful life of underground cable has rarely
exceeded 20 years, and has occasionally been as short as 10 to 12 years.
Catastrophic failure of older HMWPE, XLPE, and EPR cable is now beginning to
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occur due to water damage known as "water trees." Water trees are formed in
the
polymer when medium to high voltage alternating current is applied to a
polymeric
dielectric (insulator) in the presence of liquid water and ions. As water
trees grow,
they compromise the dielectric properties of the polymer until the insulation
fails.
Many large water trees initiate at the site of an imperfection or contaminant,
but
contamination is not a necessary condition for water trees to propagate.
Water tree growth can be eliminated or retarded by removing or minimizing
the water or ions, or by reducing the voltage stress. Voltage stress can be
minimized
by employing thicker insulation. "Clean room" manufacturing processes can be
used
to both eliminate ion sources and minimize defects or contaminants that
function as
water tree growth sites. Another approach is to change the character of the
dielectric,
either through adding water tree retardant chemicals to polyethylene or by
using
more expensive, but water tree resistant, plastics or rubbers. All of these
approaches
have merit, but only address the performance of electrical cable yet to be
installed.
For electrical cables already underground, the options are more limited.
First,
the entire failing electrical cable can be replaced, but the cost is often
prohibitive.
Second, the points of failures due to water tree propagation can be excised
and the
removed portions replaced with a splice. Unfortunately, since water trees are
not
identifiable until after cable failure occurs, splicing after cable failure
results in a
power interruption to the electric utility customers. Third, the cable can be
dried
with a desiccant fluid such as nitrogen in order to remove the water that
initiates the
water tree. While this approach improves the dielectric properties of the
underground cable, it requires perpetual maintenance to replace large and
unsightly
nitrogen bottles that remain coupled to the cable.
A more promising approach to retard failure of underground cable is to inject
a silicone fluid such as, for example, CABLECURE~, into the electrical cable
conductor strands. CABLECURE reacts with water in the underground cable and
polymerizes to form a water tree retardant that is more advanced than those
used in
the manufacture of modern cables. The dielectric properties of the cable are
not only
stabilized by CABLECURE, but actually improved dramatically.
However, the devices and methods used to treat underground electrical cables
with CABLECURE do have drawbacks. Different methodologies are employed
depending upon the type of cable being treated. There are two main classes of
cables, underground residential distribution (URD) cables which are relatively
small
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cables, and feeder cables, which are larger cables which often supply the URD
cables.
Regarding the treatment of feeder cables with CABLECURE, a major
problem is the ability of splices which are often encountered in the feeder
cable to
hold the pressure required to inject perhaps miles of the feeder cable with
CABLECURE. The larger the overall cable diameter, the larger the splice, and
the
higher the hoop forces created by the pressurization of the cable cavity. Due
to the
large diameter of feeder cables, there is seldom sufficient hoop strength in
the typical
splices to withstand the basic vapor pressure of the CABLECURE without
leaking,
not to mention the increased pressurization required to transport the
CABLECURE
along the miles of feeder cable. A leak of CABLECURE in the splice can create
a
contaminated path along the splice interface which may lead to eventual
failure of the
splice.
To avoid the problem of CABLECURE leaking at splices, one of two
approaches have been employed for injection of CABLECURE into feeder cables.
First, the splice can be reinforced with clamps or other devices to increase
its hoop
strength. However, this approach is limited because the force necessarily
applied by
the hose clamps or other reinforcement devices on the splice is so large that
there is
substantial deformation of the rubber material used to make the splice. The
deformation compromises the geometrical and electrical integrity of the splice
and
thus provides only a slight increase in injection pressure tolerance. A second
approach is to remove the splice prior to injecting the two separated segments
of the
electrical cable with CABLECURE, then injecting CABLECURE, and finally
injecting a second damming chemical compound into the two electrical cable
segments that physically blocks the migration of the CABLECURE into a new
splice
that is applied to the two cable segments after the CABLECURE treatment has
been
completed. An example of a damming compound is a combination of
dimethylsilicone polymers with vinyl cross-linker and a suitable catalyst. In
addition
to low viscosity and quick cure times, a damming fluid must be compatible with
all
cables, splices and other components. Drawbacks with the above method of
employing a damming compound include the additional cost of the expensive
damming compound, the necessity to install a new splice, and the possibility
that the
CABLECURE may compromise the structural integrity of the new splice if the
physical partition formed by the damming compound fails.
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Further, it has been learned that injection of damming compounds into even
short lengths near the end of a cable can create transient discontinuities in
the
penetration of the dielectric enhancement fluid. These discontinuities of
penetration
create discontinuous treatment, which at a minimum leaves some small section
of the
cable untreated for a longer period of time, increasing the risk of a post
treatment
dielectric failure. Further, there is a potential that these discontinuities
can even lead
to local electrical stress increases which may contribute to a failure in the
region
where the dam interferes with uniform penetration. Since the point of
injecting cable
is to increase its reliability and mitigate its proclivity to fail, the use of
either
reinforcing devices or damming compounds to handle sufficient injection, vapor
and
elevation-induced pressure are not ideal solutions.
CABLECURE injection can also be employed to treat water tree damage in
UIRD cables. Since the diameter of the URD cables is less than that of feeder
cables,
the splices in UItD cables can withstand the vapor pressure of CABLECURE.
Additionally, due to the typically shorter lengths of the URD cables, a lower
pressure
(0-30 psig) than the pressure employed in feeder cables is required to
transport the
CABLECURE through the URD cable; therefore, the splices in the U1RD cable are
not subjected to the moderate pressures (30-120 psig) desired to inject
typically
longer feeder cable and their integral splices. However, because an URD cable
does
not have enough interstitial volume in the strands of the cable to hold
sufficient
CABLECUIZE for maximum dielectric performance, URD cables require an
extended soak period of 60 days or more to allow for additional CABLECUIZE to
diffuse from the cable strands into the polyethylene. When very long URD
cables or
URD cables with large elevation changes are encountered, moderate to medium
(120-350 psig) pressure injection of CABLECURE may be required. The moderate
to medium pressure addition of CABLECURE to an URD cable therefore
necessitates removing the splices during the treatment of the cable, followed
by
adding new splices after the treatment.
A need thus exists for devices and methods whereby expensive damming
compounds are not required to block the contact of repair chemicals with the
replacement splice in feeder cables.
A need also exists for devices and methods in which both a separate conduit
for injecting CABLECURE into a feeder cable as well as a separate replacement
splice are not required.
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A further need exists for devices and methods in which repair chemicals can
be injected into URD cables at moderate to medium pressures without
compromising
the structural integrity of splices.
Summar~r of the Invention
A device and method for repairing and electrically connecting, in a first
embodiment, at least two sections of electrical cable includes an elongate
conduit, for
example, a tube having two open ends that are each adapted to receive an end
of an
electrical cable section. The elongate conduit has an interior wall
longitudinally
dividing the elongate conduit into two portions, each portion having a hollow
interior
for containing the end of one of the two electrical cable sections. The
elongate
conduit also has an orifice in each of the two portions communicating with the
hollow interior of that portion. A closure device, such as a threaded plug, is
mateable
with each orifice. Additionally, the device further comprises a fluid-tight
seal over
the juncture of each electrical cable section end and at each end of the
elongate
conduit. In operation, water damage to the electrical cable portions is
repaired by
securing an end of an electrical cable section in the hollow interior of each
of the two
portions of the elongate conduit, sealing those junctures, and passing
repairing
chemicals through the orifices in the elongate conduit, into the hollow
interior of
each of the two portions of the elongate conduit, and into the interior of the
sections
of the electrical cable. The secondary addition of damming chemicals through
the
elongate conduit and into the electrical cable sections is not required. The
sections of
electrical cable are electrically connected when secured in the hollow
interior of the
two portions of the elongate conduit; therefore, the elongate conduit alsa
functions as
a splice electrically joining the two wire sections.
Preferably, the elongate conduit further comprises an annular groove adjacent
each elongate conduit end, on the hollow interior and intersecting the orifice
to
augment fluid flow. The elongate conduit also preferably comprises an annular
groove adjacent each elongate conduit end and around the elongate conduit
exterior
for strain relief. Most preferably, the elongate conduit also comprises an
annular
groove adjacent each elongate conduit end and around the elongate conduit
exterior
that is sized to receive an interior seal locatable between the elongate
conduit and the
fluid-tight sheath.
In another embodiment of the present invention, an end of a single electrical
cable is secured to an end of an elongate conduit having a hollow interior
that
contains the electrical cable end. A single orifice communicates with the
hollow
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interior for passage of chemicals therebetween. A single fluid-tight seal is
located
over the juncture of the single electrical cable end and end of the elongate
conduit.
In another embodiment of the present invention, the cable connector includes
an interior connector and an injection fitting. The interior connector
connects the
interior ends of the two sections of electrical cable and includes an elongate
hollow
electrically conductive conduit having open ends adapted to receive the
interior ends
of the two sections of electrical cable. The interior connector also includes
a fastener
for securing the interior ends of the two sections of electrical cable in the
open ends
of the elongate hollow electrically conduit. Another component of the interior
connector is a stress control tubing that is adapted to cover the elongate
hollow
electrically conductive conduit. An insulation sleeve covers the stress
control tubing.
Compression rings located on the insulation sleeve adjacent each of the open
ends of
the elongate hollow electrically conductive conduit secure the insulation
sleeve to the
elongate hollow electrically conductive conduit. The interior connector also
includes
a metal wrap adapted to cover the insulation sleeve and the compression rings.
An
outer sheath is adapted to cover the metal wrap to complete the assembly of
the
interior connector. Preferably, the stress control tubing, compression rings
and outer
sheath are heat shrunk to produce a fluid tight assembly. The injection
fitting
includes a cable adaptor that is attachable to the outer surface of one of the
electrical
cable sections. The cable adaptor supports an exterior housing and is located
on the
outer surface of the electrical cable section at a position remote from the
exterior end
of the electrical cable section to leave exposed a portion of the outer
surface of the
electrical cable section adjacent the exterior end thereof. The injection
fitting also
includes a sleeve having a first end, a second end and a fluid injection
opening. The
first end of the sleeve is adapted to fit over the exposed portion of the
outer surface of
the electrical cable section adjacent the exterior end thereof. The second end
is
adapted to fit over a conductor contact attached to the central conductor
portion of
the electrical cable section. In this manner, the sleeve creates a fluid tight
seal for
passage of repair fluid into the fluid injection opening, through one
electrical cable
section, through the interior connector and through the other electrical cable
section.
Preferably, the sleeve can be heat shrunk to create the aforesaid fluid tight
fit.
Brief Description of the Drawings
The foregoing aspects and many of the attendant advantages of this invention
will become more readily appreciated as the same becomes better understood by
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reference to the following detailed description, when taken in conjunction
with the
accompanying drawings, wherein:
FIGURE 1 is a perspective view, partially exposed, of a cable connector of
the present invention;
S FIGURE 2 is a side view of the cable connector of the present invention;
FIGURE 3 is a side view of a first embodiment of the cable connector of the
present invention secured to a cable for injection of cable damage repair
chemicals
therethrough and for electrical connection of the cable with a second cable;
FIGURE 4 is a side view of a second embodiment of the cable connector of
the present invention secured to a cable for injection of cable damage repair
chemicals therethrough and for electrical connection of the cable with a
second cable;
FIGURE 5 is a side view, partially exposed, of a third embodiment of the
cable connector of the present invention secured to a cable for injection of
cable
damage repair chemicals therethrough and for electrical connection of the
cable with
a second cable;
FIGURE 6 is a detail view of FIGURE 5;
FIGURE 7 is a side view, partially exposed, of a fourth embodiment of the
cable connector of the present invention secured to a cable for injection of
cable
damage repair chemicals therethrough and for electrical connection of the
cable with
a second cable;
FIGURE 8 is a side view of a fifth embodiment of the cable connector of the
present invention secured to a cable for injection of cable damage repair
chemicals
therethrough and for electrical connection of the cable with a second cable;
FIGURE 9 is a side view of a sixth embodiment of the cable connector of the
present invention secured to a cable for injection of cable damage repair
chemicals
therethrough and for electrical connection of the cable with a second cable;
FIGURE 10 is a side view of first and second electrical cable sections
prepared for connection by a seventh embodiment of the cable connector of the
invention;
FIGURE I 1 is a side view of the interior connector components of the
seventh embodiment of the cable connector of the present invention arranged on
the
first and second electrical cable sections prior to installation;
FIGURE I2 is a partially exposed side view showing the attachment of the
conduit of the interior connector of the seventh embodiment of the cable
connector of
the present invention to the first and second electrical cable sections;
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FIGURE 13 is a side view showing a first sealing step for providing a fluid
tight seal at the joints of the conduit with the first and second electrical
cable sections
of FIGURE 12;
FIGURE 14 is a side view showing a second sealing step for providing a fluid
tight seal at the joints of the conduit with the first and second electrical
cable sections
of FIGURE 12;
FIGURE 15 is a side view showing attachment and heat shrinking of the
stress control tubing over the conduit of the interior connector of the cable
connector
of the seventh embodiment of the present invention;
FIGURE 16 is a side view showing attachment and heat shrinking of the
insulation sleeve over the stress control tubing of the interior connector of
the cable
connector of the seventh embodiment of the present invention;
FIGURE 17 is a side view showing heat shrinking of the compression rings
over the ends of the stress control tubing of the interior connector of the
cable
connector of the seventh embodiment of the present invention;
FIGURE 18 is a side view showing the application of metal wrap over the
stress control tubing of the interior connector of the cable connector of the
seventh
embodiment of the present invention;
FIGURE 19 is a side view showing the reconnection of the optional shielding
wires of the first and second electrical cable sections;
FIGURE 20 is a side view showing the application of a second metal wrap
when shielding wires are present;
FIGURE 21 is a side view showing the attachment and heat shrinking of the
outer sheath over the second metal wrap of the interior connector of the cable
connector of the seventh embodiment of the present invention;
FIGURE 22 is a side view showing the interior connector of the cable
connector of the seventh embodiment of the present invention completely
installed
between first and second electrical cable sections;
FIGURE 23 is a partially exposed side view of the sleeve of the injection
fitting of the seventh embodiment of the cable connector of the present
invention
attached to the exterior end of the cable section and to conductor contact;
FIGURE 24 is an exposed detail view of a first embodiment of the fluid
injection opening of the sleeve of the injection fitting of the seventh
embodiment of
the cable connector of the present invention;
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FIGURE 25 is an exposed detail view of a second embodiment of the fluid
injection opening of the sleeve of the injection fitting of the seventh
embodiment of
the cable connector of the present invention;
FIGURE 26 is an exposed detail view of a third embodiment of the fluid
injection opening of the sleeve of the injection fitting of the seventh
embodiment of
the cable connector of the present invention;
FIGURE 27 is an exposed detail view of a fourth embodiment of the fluid
injection opening of the sleeve of the injection fitting of the seventh
embodiment of
the cable connector of the present invention; and
FIGURE 28 is an exposed detail view of a fifth embodiment of the fluid
injection opening of the sleeve of the injection fitting of the seventh
embodiment of
the cable connector of the present invention.
Detailed Description of the Preferred Embodiment
FIGURES l and 2 depict a cable connector 2 of the present invention in the
form of an elongate conduit which may be, for example, a tube, pipe or any
other
similarly shaped device capable of fluid transport. The cable connector has an
exterior 4, ends 6 and 7, and an interior 8 that is divided by an interior
wall 10 into
two hollow portions 12 and 14. The hollow portions 12 and 14 are each sized
and
shaped to receive an end of an electrical cable or cable section. A portion of
a cable
that has been stripped to remove the outer insulation from the cable is
inserted into
each hollow portion. The ends of the cables are then secured to the cable
connector
by crimping each end 6 and 7 of the connector. Crimping guides 28 and 30 are
provided on the exterior 4 of the connector to demark the appropriate location
of
crimping. Strain relief grooves 24 and 26 are located on the exterior 4 of the
cable
connector adjacent the crimping guides 28 and 30, respectively, and provide
relief
from strain forces generated as the cable connector is crimped.
Two orifices 16 and 18 are provided in the ends 6 and 7 of the cable
connector 2 to allow a cable damage repair chemical to be injected into the
cable.
Orifice 16 communicates with the hollow portion 12 of the cable connector, and
orifice 18 communicates with the hollow portion 14. Each orifice 16 and 18 is
preferably threaded to allow the orifice to be closed after chemicals have
been
pumped through the orifice, as described in further detail below. To
facilitate even
fluid flow through the interior 8 of the cable connector, interior
circumferential
grooves 20 and 22 are formed around the interior of the hollow portions 12 and
14,
respectively. The interior grooves 20 and 22 preferably intersect orifice 16
and
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orifice 18, respectively, to channel chemicals pumped through the orifice
around the
exterior of each cable contained in the ends of the cable connector.
The exterior 4 of the cable connector 2 is also formed with circumferential
seal grooves 32 and 34 adjacent the ends 6 and 7 of the connector,
respectively. The
S seal grooves are sized to receive an O-ring or other seal known in the art,
to
optionally provide an enhanced seal between the cable connector 2 and
electrical
cable sections or cables, as described in further detail below.
FIGURE 3 shows a first embodiment for attachment of the cable connector 2
to an electrical cable in which an O-ring or other seal is not employed in
seal
groove 32, and seal groove 32 is not present. Instead, broad band seals 33 can
be
employed between sheath 36 and connector 2 and cable 38. Alternatively, sheath
36,
itself, may provide a tight enough seal without seals if sheath 36 is, for
example,
vinyl. Also, instead of broad band seals 33, an adhesive can be employed
between
sheath 36 and connector 2 and cable 38. As shown in FIGURE 3, sheath 36 is
initially placed over the end 6 of the cable connector 2. The sheath 36 is
preferably
comprised of a liquid tight material that can be either resilient or can have
heat-
shrink properties and can be, for example, rubber, vinyl, polyethylene, or
nylon.
Cable 38 that is comprised of, for example, cable insulation 40 and cable
strands 42,
is inserted into the end of the cable connector and secured in the hollow
portion 12
by crimping the connector. Optional sheath connectors 44, which may be, for
example, steel bands or clamps, or other material with high tensile strength,
may be
placed around the sheath 36 to provide additional hoop strength to secure the
sheath 36 at the juncture of the end 6 of cable connector 2 and the cable
insulation 40
of the cable 38.
Once the cable 38 is secured to the cable connector 2, cable water-damage
repair chemicals, such as, for example, a silicone fluid (CABLECURE~), may be
injected into the cable 38. The repair chemicals are supplied from a pressure
source
known in the art through a tube 46 in communication with a tube fitting 48.
Tube
fitting 48 is preferably threadedly mateable with orifices 16 and 18, and
preferably
also functions as a closure device. As shown in FIGURE 3, after passing
through
tube fitting 48, the silicone fluid flows through orifice 16, into hollow
portion 12,
where it contacts cable strands 42 of cable 38, passes out of end 6 of
elongate
conduit 2 and into cable 38 for a predetermined distance. After sufficient
silicone
fluid has been injected into the cable the tube 46 is removed. The tube
fitting 48 may
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remain in the orifices 16 and 18 and may be plugged to the orifices 16 and 18,
or tube
fitting 48 may be removed and a plug fitting installed in orifices 16 and 18.
After termination of cable water-damage repair chemical treatment and after
the tube 46 is detached from the tube fitting 48, the electrical cable or
cable sections
are electrically energized. It will be appreciated that because the cable
connector 2 is
electrically conductive, cable 38 is electrically connectable to any other
cable also
attached to the cable connector. Note that while FIGURE 3 only shows and
describes the chemical repair and electrical connection of a single cable 38
to the
cable connector 2 at end 6, it is understood that a second cable can be
attached at
end 7 of the cable connector 2 for a similar chemical repair and electrical
connection.
In other words, the present invention encompasses both a cable connector 2
having
only an end 6 and not an end 7 to secure only a single cable 38 with some
other
known electrically conductive connection to other devices in place of end 7,
as well
as a cable connector 2 having both an end 6 and an end 7 to secure, repair and
electrically connect two cables 38.
Referring to FIGURE 4, a second embodiment of the present invention is
shown which is similar to the first embodiment of the present invention of
FIGURE 3
and in which the same element numbers are used as in FIGURE 3 to describe like
elements. The primary difference between the first embodiment of FIGURE 3 and
the second embodiment of FIGURE 4 is that in the second embodiment of
FIGURE 4, an O-ring or seal 50 is located in the seal groove 32 adjacent the
end 6 of
the cable connector 2. The seal 50 is therefore located between the end 6 of
the cable
connector 2 and the sheath 36. A second seal 50 is also located between the
sheath 36 and the cable insulation 40 of cable 38. Additionally, sheath 36 is
bowed
such that concave portions are present for the placement of seals 50 between
sheath 36 and cable 38, and between sheath 36 and the end 6 of the cable
connector 2, respectively. Additionally, sheath 36 is bowed such that a convex
center portion provides additional closure at the juncture of attachment of
cable 38 in
end 6 of the cable connector 2.
Referring to FIGURES 5 and 6, a third embodiment of the present invention
is shown in which the same element numbers are used as are used in FIGURE 3,
which shows the first embodiment, to describe like elements. The primary
difference
between the first embodiment of FIGURE 3 and the third embodiment of
FIGURES 5 and 6 is that the third embodiment of FIGURES 5 and 6 does not
employ a sheath 36 at the juncture of the end 6 of cable connector 2 and the
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insulation 40 of the cable 38. Instead, a threaded seal 52 is located at the
juncture of
end 6 of cable connector 2 and insulation 40 of cable 38. Threaded seal 52 is
comprised of a preferably annular inner seal member 54 having an exterior
surface 56. On exterior surface 56 are threads 58. Compression ring 59 is
located on
inner seal member 54 with O-ring seal 57 located therebetween. Threaded seal
52
also includes outer seal member 60 which is preferably annular, and which has
threads 64 thereon that are mateable with threads 58 of inner seal member 54.
Elastomeric packing 68 is located between the junctures of both compression
ring 59
and inner seal member 54 with insulation 40 of cable 38, and elastomeric
packing 69
is located between inner seal member 54 and end 6 of cable connector 2. Inner
seal
member 54 has a passageway 70 therethrough for passage of cable water-damaged
repair chemicals through threaded seal 52 and into contact with cable strands
42 of
cable 38, in a manner described above for the first embodiment of the present
invention. In operation, threaded interconnection of inner seal member 54 and
outer
seal member 60 imparts an axial force through compression ring 59 and into
elastomeric packing 68 while inner seal member 54 imparts an opposite axial
force
on elastomeric packing 69 to form a complete seal. Note that in the third
embodiment, connector 2 can be a connector known in the art, with the elements
of
the third embodiment being located over cable strands 42 and between
insulation 40
and connector 2.
Now referring to FIGURE 7, a fourth embodiment of the present invention is
shown which includes elements described in the first embodiment of the present
invention of FIGURE 3, these elements having like element numbers to those in
the
first embodiment of FIGURE 3. Unlike the first embodiment of the present
invention of FIGURE 3 in which sheath 36 is located at the juncture of the end
6 of
cable connector 2 and insulation 40 of cable 38, in the fourth embodiment of
the
invention of FIGURE 7, spring seal 72 is employed. Spring seal 72 is comprised
of a
spring receptacle portion 74 which is preferably annular in shape and which
has a
hollow interior 76 which is sized to receive spring 78. Spring seal 72 also
includes
annular elongate portion 80 which is mateable with hollow interior 76 of
spring
receptacle portion 74 to compress spring 78 when spring seal 72 is secured.
Hole 82
passes through spring receptacle portion 74, communicates with hollow interior
76
thereof, and is coaxially aligned with hole 84 when elongate portion 80 is
inserted
into hollow interior 76 of spring receptacle portion 74. Pin 86 is adapted to
pass
through hole 82 of spring receptacle portion 74 and hole 84 of elongate
portion 80 to
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lock elongate portion 80 in spring receptacle portion 74. O-ring-type seal 88
is
present between elongate portion 80 and spring receptacle portion 74 in hollow
interior 76 thereof; O-ring-type seal 90 is present between spring receptacle
portion 74 and insulation 40 of cable 38, and O-ring-type seal 92 is present
between
elongate portion 80 and end 6 of cable connector 2 to provide a fluid-tight
environment through which cable repair chemicals can pass. Passageway 94 is
located through spring receptacle portion 74 to allow cable repair chemicals
to pass
through spring seal 72 and contact cable strands 42 of cable 38.
Referring to FIGURE 8, a fifth embodiment of the present invention is shown
having elements that are also present in the first embodiment of the present
invention
of FIGURE 3, these like elements having the same element numbers as those used
in
the first embodiment of FIGURE 3. Unlike the first embodiment of the present
invention of FIGURE 3 in which sheath 36 is located at the juncture of the end
6 of
cable connector 2 and insulation 40 of cable 38, in the fifth embodiment of
FIGURE 8, a fluid-tight connection between cable 38 and connector 2 is created
by
cable shoulder 98 which is defined by first portion 100 of insulation 40
having a
standard outside diameter and by a second portion 102 of insulation 40 having
an
outside diameter less than the outside diameter of first portion 100 of
insulation 40 of
cable 38. A seat 104 in hollow portion 12 of interior 8 of connector 2 is
mateabie
with shoulder 98. More specifically, seat 104 includes first portion 106 that
has an
inside diameter less than the outside diameter of second portion 102 of
insulation 40,
and also includes a second portion 108 that has an inside diameter greater
than the
outside diameter of second portion 102 of insulation 40. Thus, second portion
102 of
insulation 40 is insertable into second portion 108 of hollow portion 12, but
second
portion 102 of insulation 40 has an outside diameter too great to clear the
lesser
inside diameter of first portion 106 of hollow portion 12 such that shoulder
98 of
insulation 40 mates with seat 104 of hollow portion 12 and abuts against end 6
of
connector 2. To further ensure a fluid-tight fit between cable 38 and
connector 2,
annular seal 110, for example, an O-ring or the like, can be located between
second
portion 108 of hollow portion 12 and second portion 102 of insulation 40.
Referring to FIGURE 9, a sixth embodiment of the present invention is
shown having elements that are also present in the first embodiment of the
present
invention of FIGURE 3, these like elements having the same element numbers as
those used in the first embodiment of FIGURE 3. In the sixth embodiment of
FIGURE 9, a configuration is shown which allows cable connector 2 to pass
cable
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repair or desiccant fluids therethrough such that these fluids are originated
only at
one end of cable connector 2, i.e., end 6, and not at both ends 6 and 7 of
cable
connector 2, whereby cable repair or desiccant fluids flow in a single
direction
through cable connector 2. The above configuration is useful when cable
connector 2
is located remotely from the initial injection point of the cable repair
chemicals into
cable 38. Thus, as shown in FIGURE 9, tube 96 is employed to connect tube
fitting 48 of end 6 with tube fitting 48 of end 7 such that cable repair
chemicals
entering end 6 of cable connector 2 are not blocked by interior wall 10, but
instead
pass through tube fitting 48 of end 6, through tube 96, through tube fitting
48 of
end 7, and out of end 7 into the other portion of cable 38 which is joined by
cable
connector 2.
Referring to FIGURES 10-27, a seventh embodiment of the subject invention
is shown, which includes an interior connector portion and an injection
fitting
portion. More specifically, referring to FIGURE 10, electrical cable sections
120 are
shown after being prepared for attachment to the interior connector components
of
the seventh embodiment of the subject invention. Electrical cable sections 120
each
include a central core 122 that is surrounded by insulation 124. Core screen
126
covers insulation 124. Shielding wires 130 cover core screen 126. Oversheath
130,
which is optional, covers shielding wires 128. The electrical cable sections
120 are
each prepared by removing a portion of insulation 124 to expose central core
122.
Also, a portion of core screen 126 is removed to expose insulation 124.
Shielding
wires 128 are bent away from central core to lie substantially parallel to the
longitudinal axis of electrical cable section 120.
As will be further described below, conduit 132 of the interior connector
portion of the subject invention will electrically connect each central core
122 of
electrical cable sections 120. Conduit 132 will abut the exposed ends of
insulation 124 of each of electrical cable sections 120; it is therefore
important to
ensure that the structural integrity of insulation 124 remains undamaged and
that its
surface is free from any previous jointing material if conduit 132 serves as a
replacement splice.
Referring to FIGURE 11, attachment of conduit 132 to the central core 122 of
each electrical cable section 120 is shown. Conduit 132 is an elongate hollow
electrically conductive tubular member having a first end 134 and a second end
136.
Adjacent to first end 134 and second end 136 of conduit 132 are a plurality of
threaded openings 138; preferably, between two and four threaded openings 138
are
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present adjacent each of first end 134 and second end 136. Threaded openings
138
are sized to receive bolts 140. Bolts 140 are preferably of a length
sufficient to
contact central core 122 of electrical cable section 120 when bolts 140 are
tightened
without impeding the flow of cable repair chemicals through electrical cable
sections 120. As stated above, conduit 132 is hollow, and therefore has an
opening 142 and 144 adjacent first end 134 and second end 136, respectively.
Still refernng to FIGURE 11, prior to attaching conduit 132 to central
core 122 of the electrical cable sections 120, additional components of the
interior
connector portion of the subject invention are placed over the two electrical
cable
sections 120. More specifically, outer sheath 146 is first placed over one of
the two
electrical cable sections 120. Next, at least two compression rings 148 are
placed
over the same electrical cable section 120 such that the compression rings 148
are
located adjacent to outer sheath 146, and in closer proximity to the end of
the
electrical cable section 120. Stress control tubing 150 is placed over the
other
electrical cable section 120, and insulation sleeve 152 is placed over stress
control
tubing 150. Stress control tubing 1 S0, as described further below, is located
over
conduit 132, which connects the two electrical cable sections 120. Stress
control
tubing 150 is employed to provide electrical stress control around the joint.
Stress
control tubing 150 is preferably made of a carbon-based filler in a heat
shrinkable
polymer matrix. Insulation sleeve 152 provides electrical insulation and
screening,
as well as sealing. Insulation sleeve 152 is preferably made of an insulating
elastomer with an external conductive screen. Compression rings 148, as will
be
discussed further below, provide a fluid tight seal over the points of
attachment of
stress control tubing 150 and insulation sleeve 152 to the electrical cable
sections 120. Compression rings 148 are preferably comprised of a high density
polyethylene-based cross-linked material. Outer sheath 146 is the exterior
layer of
the interior connector portion of the cable connector of the seventh
embodiment of
the present invention. Outer sheath 146 is preferably comprised of a heat
shrink
material, such as low density polyethylene-based cross-linked material, and
provides
protection from the external environment. Preferably, all of outer sheath 146,
compression rings 148, stress control tubing 150, and insulation sleeve 152
are
comprised of a heat shrink material such that the application of sufficient
thermal
energy will cause the structure to shrink in diameter in order to ensure a
fluid-tight
fit.
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Referring to FIGURE 12, conduit 132 is attached to central core 122 of each
of the cable sections 120 by insertion of central core 122 (that has been
exposed by
removing a portion of insulation 124 therefrom) into one of openings 142 and
144 of
first end 134 and second end 136, respectively, of conduit 132. Bolts 140 are
then
S placed in threaded openings 138 of conduit 132. Bolts 140 are hand
tightened.
Bolts 140 are preferably shear bolts such that the application of sufficient
torque
thereto will cause the heads of bolts 140 to shear off. As shown in FIGURE 12,
a
ratchet or wrench is employed to provide sufficient torque for the heads of
bolts 140
to shear off. Next, the gaps created in threaded openings 138 by the removal
of the
heads of bolts 140 are filled with sealing clay, for example, Raychem clay
electrical
grade filler. Next referring to FIGURE 13, the joints between first end 134
and
second end 136 of conduit 132 with insulation 124 of the electrical cable
sections 120 are covered with rubber tape 154 having an elastomeric property
such
that the tape can be stretched to about one half of its original width to
ensure a tight
seal. Rubber tape 154 is wrapped over conduit 132 and the insulation 124 of
electrical cable sections 120 such that rubber tape 154 covers at least one-
half inch of
conduit 132 and one-half inch of insulation 124 on both first end 134 and
second
end 136 of conduit 132. Next, referring to FIGURE 14, a void-filling tape 156,
preferably Raychem stress grading yellow void filling mastic, is wrapped over
conduit 132, insulation 124 and rubber tape 154. More specifically, void-
filling
tape 156 has elastomeric properties such that it can be stretched to about one
half of
its original width during the wrapping process. Void-filling tape 156 is
wrapped over
a sufficient portion of first end 134 and second end 136 of conduit 132 to
cover
threaded openings I38 in which sheared bolts 140 are located. Void-filling
tape 156
can also optionally be employed to wrap the juncture of insulation 124 and
core
screen 126 formed by removal of a portion of core screen 126 to expose
insulation 124.
Referring to FIGURE 15, stress control tubing 1 S0, which had previously
been located over one of the two electrical cable sections 120, is now moved
to cover
conduit 132 connecting the two electrical cable sections 120. The stress
control
tubing 150 is of sufficient length to cover conduit 132, the exposed portion
of
insulation 124, and a portion of core screen 126. A thermal heat source, such
as a
propane torch, is employed to shrink stress control tubing 150. More
specifically,
shrinking is started at the center of stress control tubing 150 and is worked
outwardly
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to both ends thereof in order to ensure that stress control tubing 150 is
completely
shrunk and substantially wrinkle free.
Referring to FIGURE 16, insulation sleeve 152, which has previously been
located over the same electrical cable section 120 as was stress control
tubing 1 S0, is
now moved to cover stress control tubing 150, which has been heat shrunk over
conduit 132. insulation sleeve 152 is of sufficient length to substantially
cover stress
control tubing 1 S0. insulation sleeve 152 is heat shrunk with a thermal
energy
source, such as a propane torch, by first shrinking the center portion of
insulation
sleeve 152 until a sufficient portion of insulation sleeve 152 has been heat
shrunk so
insulation sleeve 152 does not rotate with respect to electrical cable
sections 120
when an attempt is made to twist it by hand. Next, one of the two outer
portions of
insulation sleeve 152 is heat shrunk; however, the exterior end of the outer
portion
being heat shrunk is not heat shrunk at this time. The other outer portion of
insulation sleeve 152 is then heat shrunk, again leaving the end of this outer
portion
unshrunk. The end of the first outer portion to be heat shrunk is then heat
shrunk.
Finally, the end of the second outer portion is heat shrunk to complete the
process.
As shown in FIGURE 17, compression rings 48, which were located on one
of the two electrical cable sections 120 are moved over insulation sleeve 152
while
insulation sleeve 152 is still hot from heat shrinking. One compression ring
148 is
oriented at each of the two ends of insulation sleeve 152. Compression rings
148 are
then heat shrunk with a propane torch, for example, onto insulation sleeve
152.
Referring to FIGURE 18, an alloy braid 158, comprised of, for example,
copper alloy, is wrapped over insulation sleeve 152 and compression rings 148.
As
shown in FIGURE 19, shielding wires 128 from each of electrical cable sections
120
are bent from their configuration away from the work area to now be positioned
over
alloy braid 158. The ends of each shielding wire 128 group are coupled to a
connector 160. The two connectors 160 are then connected by a wire lead 162 to
interconnect the two shielding wire 128 groups.
As shown in FIGURE 20, outer sheath 146 is moved from its position over
one of the electrical cable sections to cover alloy braid 164. Outer sheath
146 is heat
shrunk with, for example, a propane torch, starting at the center of outer
sheath 146
and working toward the outer edges thereof until outer sheath 146 tightly
encases
alloy braid 164. The above-detailed configuration of the interior connector
portion of
the seventh embodiment of the present invention, as shown in FIGURES 11-22,
facilitates the passage of cable repair chemicals through electrical cable
sections 120
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while maintaining electrical conductivity between the two electrical cable
sections 120.
Referring to FIGURES 23-28, the injection fitting portion of the seventh
embodiment of the subject invention is shown. Specifically referring to FIGURE
23,
an electrical cable section 120 having a central core 122 is shown. It should
be noted
that the injection fitting portion of the subject invention, to be described
further
below, can be connected to an exterior end of an electrical cable section 120
whereby
the interior end of this same electrical cable section 120 is interconnected
with the
interior end of another electrical cable section 120 by the above-described
interior
connector portion of the subject invention of FIGURES 11-20. As shown in
FIGURE 23, injection fitting 176 of the seventh embodiment of the present
invention
is connectable to a cable splice 178 that can be, for example, Elastomold
model
No. M650S or model No. 755LR. Cable splice 178 includes splice housing 180, a
hollow member that is removably attachable to splice base 182. The end of
splice
housing 180 remotely located from splice base 182 includes adaptor opening 184
in
which cable adaptor 186 can be located. Cable adaptor 186 is a collar
attachable to
electrical cable section 120, preferably around insulation 124. Cable splice
178 also
includes conductor contact 188 that has an end attachable to the end of
central
core 122 of electrical cable section 120. The end of conductor contact 188
remote
from central core 122 of electrical cable section 120 is attachable to splice
base 182
by bolt 190. In this manner, conductor contact 188 provides electrical
interconnection between central core 122 of electrical cable section 120 and
cable
splice 178. Unlike prior art configurations of cable splice 178, cable splice
178 as
shown in relation to the present invention has a relatively truncated cable
adaptor 186
such that a portion of central core 122 of electrical cable section 120
between cable
adaptor 186 and conductor contact 188 is exposed and not covered by cable
adaptor 186. This configuration facilitates the orientation of injection
sleeve 192 of
injection fitting 176 over the exposed portion of insulation 124 to cover
cable
core 122 of electrical cable section 120. More specifically, injection sleeve
192 is
oriented over both insulation 124 and contact end 194 of conductor contact 188
to
form a fluid injection chamber 196 in which central core 122 of electrical
cable
section 120 is located. Injection port 198 is located in injection sleeve 192
to provide
fluid communication into fluid injection chamber 196 such that repair
chemicals can
be injected into injection port 198 to enter fluid injection chamber 196 and
pass into
central core 122 of electrical cable section 120. These repair chemicals can
pass
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through this electrical cable section 120 and into a second electrical cable
section 120
if the two electrical cable sections 120 are interconnected by the interior
connector
portion of the present invention as shown in FIGURES 11-22. However, it will
be
readily understood by one skilled in the art that the above-described interior
connector portion of the subject invention of FIGURES 11-22 and the present
injection fitting 176 can be used either in concert with or separately from
one another
to facilitate flow of cable repair chemicals through one or more electrical
cable
sections 120.
Referring to FIGURES 24-28, injection sleeve 192 and various embodiments
of injection port 198 are described in detail. Injection sleeve 192 is
preferably
comprised of polyethylene applied with a hot melt adhesive. Most preferably,
injection sleeve 192 is comprised of a heat shrink material such that the
application
of thermal dynamic energy from a thermal source, such as a propane torch or
the like,
facilitates a fluid tight fit of injection sleeve 192 over both insulation 124
of electrical
cable section 120 and contact end 194 of conductor contact 188. As shown in
FIGURE 24, in a first embodiment, injection port 198 can be an opening that is
drilled into injection sleeve 192 after injection sleeve 192 has been heat
shrunk and
has cooled. This opening is then tapped with internal threads to facilitate a
threaded
interconnection between injection sleeve 192 and a cable repair chemical
source
having an externally threaded connector (not shown).
Referring to FIGURE 25, a second embodiment of injection port 198 is
shown. In this second embodiment, a hole defining injection port 198 is first
drilled
in injection sleeve 192 prior to heat shrinking thereof. This hole is tapped
and a
temporary externally threaded fitting 200 is placed in the hole. Injection
sleeve 192
is then heat shrunk in the manner described above and the externally threaded
fitting 200 is removed, leaving an internally threaded injection port 198
through
which cable repair chemicals can pass from a cable repair chemical source
having an
externally threaded connector (not shown).
Referring to FIGURE 26, a third embodiment of injection port 198 is shown.
In this third embodiment, a hole is drilled in injection sleeve 192 prior to
shrinking
thereof. Internally threaded bushing 202 defining the injection port 198 is
placed in
the hole and adhesively connected to injection sleeve 192. Injection sleeve
192 is
then heat shrunk in the manner described above, and cable repair chemicals can
pass
through injection port 198 by attachment of an externally threaded connector
from a
cable repair chemical source (not shown) to externally threaded bushing 202.
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Referring to FIGURE 27, a fourth embodiment of injection port 198 is
shown. In this embodiment, injection sleeve 192 is first heat shrunk in the
manner as
described above. Next, a hole is drilled into injection sleeve 192, forming
injection
port 198. A tube preferably comprised of a synthetic polymer is inserted in
injection
port 198 and is sealed onto injection sleeve 192 by using a thermal adhesive,
hot air,
or ultrasonic energy in a manner known in the art.
Referring to FIGURE 28, a fifth embodiment of injection port 198 is shown.
In this embodiment, injection sleeve 192 is first heat shrunk in the manner
described
above and is allowed to cool. A hole defining injection port 198 is drilled
into
injection sleeve 192. Tube 206 is inserted in injection port 198. Tube 206 has
a
plurality of angularly disposed fins 208. Fins 208 are angled outwardly with
respect
to fluid injection chamber 196 such that tube 206 can readily be inserted into
injection port 198, but removal of tube 206 from injection port 198 is
hampered by
fins 208. Additionally, fins 208 provide a physical block to prevent seepage
of fluid
from between tube 206 and injection sleeve 192.
Those skilled in the art will recognize that the subject invention can be used
in low, medium, or high voltage environments, and is also applicable for the
use of
air drying techniques for cable water contamination in addition to the above
described water damage repair chemical application.
While the preferred embodiments of the invention have been illustrated and
described, it will be appreciated that various changes can be made therein
without
departing from the spirit and scope of the invention.
