CORDON ELECTRIQUE ETANCHE AVEC JOINT D'ETANCHEITE DEFORMABLE

ELECTRICAL CORD SEALING ARRANGEMENT WITH A DEFORMABLE SEAL

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
According to the present invention a new electrical cord
assembly is provided for sealing in a liquid cooled pump
and/or a submersible pump. The one piece preformed
electrical cord assembly comprises an insulated electrical
cord having at least two individual insulated electrical
conductors extending from one end thereof, and a sealing
means positioned intermediate the ends of the electrical
cord assembly. The sealing means is at least partially
deformable and encapsulates a portion of the conductors
and the end of the insulated electrical cord. The sealing
means may be compressively loaded to provide a seal within
a cavity of a pump casing while maintaining the seal with
the electrical conductors. The sealing means is made of
an electrically insulating material to avoid shorting
between the bared conductors. This assembly can be
preformed and tested prior to installation in the
electrical appliance.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A one piece preformed electrical cord assembly comprising
an insulated electrical cord having at least two individual
insulated electrical conductors extending from one end thereof
for connection with electrical terminals and sealing means
intermediate the ends of said electrical cord assembly, said
sealing means being at least partially deformable and
encapsulating a portion of said conductors, the portion of said
conductors encapsulated within said sealing means including a
length stripped of insulation wherein said sealing means provides
a liquid tight seal with said conductors and said sealing means
may be compressively loaded to deform and provide a seal between
said sealing means and a cavity of slightly larger dimensions
into which the sealing means may be inserted while said sealing
means maintains the seal with said electrical conductors; said
sealing means being of an electrically insulating material.
2. A one piece preformed electrical cord assembly as claimed
in claim 1 wherein said electrical conductors are multi-strand
wires and the bared portions of said conductors are treated to
avoid wicking prior to encapsulation in said sealing means.
3. A one piece preformed electrical cord assembly as claimed
in claim 2 for use in an oil cooled submersible pump wherein said
sealing means encapsulates both a portion of said conductors and
the end of said electrical cord adjacent said extending
conductors to seal one end of said cord assembly adjacent said
sealing means.

4. A one piece electrical cord assembly as claimed in claim
3 wherein said sealing means is made of an injection molding PVC
material formed about said conductors and cord end to seal
therewith.
5. A one piece electrical cord assembly as claimed in claim
2, 3 or 4 wherein said sealing means is circular in cross-section
and includes a reduced stem portion encapsulating the end of said
electrical cord.
6. A one piece electrical cord assembly as claimed in claim
2, 3 or 4 wherein the treated portions of said conductors are
located generally centrally within the length of said sealing
means.
7. A one piece electrical cord assembly as claimed in claim l
wherein said conductors are multi-strand wires and the bared
portions of said conductors are sealed to prevent wicking along
said conductors from one side of said sealing means to the other
side thereof.
8. A one piece electrical cord assembly as claimed in claim
2, 3 or 4, wherein said conductors are treated by being tinned,
said sealing means is resiliently deformable, and is generally a
solid cylinder having a central axis with the conductors
generally aligned with said axis, whereby said sealing means is
deformable outwardly to engage and seal with such cavity by axial
compressive loading of said sealing means.
9. In a submersible pump having a pump casing defining an
electrical motor housing, a preformed electrical cord assembly

having at least two insulated electrical conductors extending
from one end thereof, said electrical cord being of the type
having an outer plastic sheath and insulation material between
said sheath and said conductors, sealing means intermediate the
ends of said electrical assembly being partially deformable and
encapsulating a portion of said sheath and a length of said
conductors extending from said assembly adjacent the end of said
sheath, the length of said conductors encapsulated within said
sealing means including a length strip of insulation with said
sealing means in direct contact with said conductors to provide a
liquid tight seal therewith, said pump casing including a cavity
for receiving the sealing means of said assembly and allowing
said conductors to pass through said casing into said motor
housing, a member adapted to engage said cavity and compressively
load said sealing means causing deformation thereof whereby said
sealing means engages said cavity and provides a liquid tight
seal therewith.
10. In a submersible pump as claimed in claim 9 wherein said
electrical conductors are multi-strand wires and the bared
portions of said conductors are treated to avoid wicking of fluid
along the strands prior to encapsulation in said sealing means.
11. In a submersible pump as claimed in claim 9 or 10 wherein
said sealing means is generally circular in cross-section and is
received within a similarly shaped cavity, said cavity including
a threaded portion to cooperate with said member which includes
threads to engage the threaded portions of said cavity.
12. In a submersible pump as claimed in claim 9 or 10 wherein
said sealing means is generally circular in cross-section and is

received within a similarly shaped cavity, said cavity including
a threaded portion to cooperate with said member which includes
threads to engage the threaded portions of said cavity, said
motor housing being filled with oil to cool a motor, said sealing
means being deformable outwardly and cooperates with said cavity
to provide said liquid tight seal along the circular portion of
said sealing means.
11

Description

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1 FIELD OF THE INVENTION
___ _ _ _________
The present invention relates to an electrical cord
assembly for use in appliances being used in a liquid
environment. More particularly the invention relates to
an electrical assembly for use in a submersible pump for
separating the oil environment within the pump from the
liquid environment to the exterior thereof.
BACKGROUND OF THE INVENTION
_____ ___
A number of sealing arrangements for electrical cords
have been developed as illustrated by United States
Patents 3,772,453 which issued to O'Brien November 13,
1973 and United States Patent 4,226,432 which issued to
Nakamizo October 7, 1980. The structures disclosed in
these patents are adapted to seal an electrical cord
assembly for applicances such as submersible pumps however
are not suitable for providing a sealing arrangement
separating two liquid environments. In this regard,
United States Patent 4,128,735 which issued December S,
1978 to Zehren and United States Patent 3,781,456 which
issued to Knowles et al. December 25, 1973 provide sealing
between two liquid environments however the first
structure is quite complicated and the second structure
requires the seal to be established during the manufacture
of the pumping unit and as such is not suitable for all
applications.
The present invention seeks to mitigate the above
problems by providing a simple structure which can be
preformed on an electrical cord and easiiy installed
during the manufacture of a submersible pump or other
appliance. Because the unit is preformed it may also be

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1 pretested to ensure the individual electrical conductors
are not shorted and thereby reduce quality control
problems with respect to the finished units.
SUMMARY OF THE INVENTION
According to the present invention a one-piece
preformed electrical cord assembly is possible comprising
an insulated electrical cord having at least two individual
insulated electrical conductors which extend from one end
of the cord and sealing means intermediate the ends of the
electrical cord assembly. The sealing means is at least
partially deformable and encapsulates a portion of the
conductorsO The portion of the conductors encapsulated
within the sealing means includes a length stripped of
insulation whereby the sealing means provides a liquid
seal with the conductors and the sealing means may be
compressibly loaded to provide a liquid seal within a
cavity while maintaining the seal with the electrical
conductors. The sealing means is made of an electrically
insulating material to isolate individual conductors. The
individual conductors which extend from the sealing means
may be easily connected to electrical terminals of the
pump or appliance without the requirement to seal the ends
of these connections as a seal is established between the
bared electrical conductors within the sealing means.
According to a preferred aspect of the invention the
individual conductors are multi-strand wires and the bared
portion of these electrical conductors are tinned prior to
being encapsulated within the sealing means. This embodi-
ment assures that wicking of fluid along the strands does
not occur whereas the sealing means about bared solid

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1 conductors assures that wicking does not occur between the
conductors and their insulating coating.
BRIEF DESCRIPTION OF THE_DRAWINGS
Preferred embodiments of the invention are shown in
the drawings wherein;
Figure 1 is a perspective view of the electrical
cord assembly passing through a wall of the pump which has
been cut away for illustrative purposes;
Figure 2 is a vertical section taken through a wall
of the pump unit with the sealing means being compressed
within a chamber of the pump casing wall;
Figure 3 is a sectional view showing the relationship
between the electrical cord and the individual conductors
and the sealing means;
Figure 4 is a cross-section taken along line A-A of
Figure 3, and;
Figure 5 is a cross-section taken along line B-B of
Figure 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The electrical cord assembly generally shown as 2 in
Figures 1 and 2 provides a liquid seal between the liquid
environment 16 to the interior of the pump casing 10 and
the exterior liquid environment 18. The electrical cord 4
is sealed within the sealing means 6 with the individual
electrical conductors 8 extending beyond the sealing means
and into the pump casing.
As can be seen with respect to Figures 1 and 2, nut
14 is threadably received within the sidewall of the pump
casing 10 to compressiqely load the sealing block 6 within
the wall of the pump casing. As the nut is screwed

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1 inwardly against friction washer 39, the sealing block is
compressed and deformed to generally thicken and move
outwardly against the sides of the apperture 19 and form a
seal therewith. The movement of the nut 14 inwardly also
causes the end of the block to abut and at least partially
seal along surface 21. The friction washer provides a
simple means of isolating the rotation of nut 14 relative
to the sealing block as rotation may reduce the seal
effectiveness.
With respect to Figure 3 it can be seen that the
individual conductors 8A and 8B of the electrical cord 4
have been bared over a portion 42 and have a tinned area
40 for sealing the individual strands of the electrical
conductor. The sealing block 14 is cast or molded about
the individual conductors to separate the individual
conductors, to electrically insulate between them and ~o
provide a seal along each conductor length. This block
seals with the outer plastic coating 11 of the individual
conductors but provides an intimate seal against the
tinned area 40 of each individual conductor to stop
movement of liquid from one environment to the other.
This tinned area in the case of a multi-strand conductor
avoids problems due to wicking of the liguid between the
individual strands of the conductor which could occur if
not for the tinned portion.
This can be more fully appreciated with respect to
Figures 4 and 5 wherein the individual strands of Figure 4
are not tinned and spaces occur between the individual
strands 50. These spaces allow the liquid to wick along
the length of the conductor and eventually move to the

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1 opposite end of the electrical cord. However as can be
seen with respect to Figure 5 the tinned area provides a
solid cross-section having substantially eliminated all
the spacing between the individual conductors such that
wicking is no longer possible. Furthermore because the
tinned area 40 provides an intimate bond with the sealing
block 6, no liquid can pass to the exterior surfaces of
this tinned area. Once the block has set the individual
conductors are locked in place and the tinned area is
generally centrally located within the block 6. This
central location assures the seal between the tinned area
and the block remains intact during compression of the
block member and thereby positively isolates the liquid
environment 16 from the liquid environment 18 disposed the
other side of the sealing block.
Returning to Figure 3, it can be seen that the
sealing block 6 is provided with a reduced stem portion 7
which positively engages the electrical cord 4. This
electrical cord has an outer casing 5 of a PVC type
material, which is encapsulated within the stem 7 to
provide a positive seal between these components. Within
the electrical cord and between the individual conductors
is an insulating-type material which is also sealed from
the liquid environment to the exterior of the sealing
block 6.
In order to produce this electrical cord assembly one
merely has to remove the outer casing 5 from one end of
the electrical cord and therewith any insulating material
between individual conductors, bare a portion of the
individual conductors and in the case of multi-strand

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1 conductors, tin a portion of the conductor (epoxy or a
potting compound could be used instead of the tinning
step) and then locate the cord within a chamber into which
an injection moldable electrically insulating is injected
to produce the sealing block 6. As can be appreciated the
individual conductors 8A and 8~ must be physically
separated to avoid shorting between the conductors. The
block material is preferrably made of an injection molding
PVC to assure good adhesion to the cord however other
materials are possible such as a thermoplastic urathane.
After the unit has been produced it may be
electrically tested to assure the conductors have not
shorted prior to assembly in a pump. This structure
avoids problems common with use of potting compounds where
the terminal ends of the oonductors are are coated to
provide a seal with the conductors and the
plastic insulating material thereof. This requires
careful installation to assure the potting compound is not
damaged during connection of the conductors with the pump
motor. With the present assembly one merely has to insert
the conductors through the pump casing, tighten a bolt
member to deform the sealing block and provide a seal. As
can be appreciated these electrical cord assemblies may be
mass produced inexpensively, and greatly simplify the
installation of the cord assembly to the pump.
Therefore the present invention provides a simple
method for sealing an electrical cord and separating two
; liquid environments. The invention utilizes the inherent
sealing affinity of the electrical conductors and the
insulating material to the material of the sealing block

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1 as well as the resilient deformation of the sealing means
when compressibly loaded.
Although the invention has been described herein in
detail it can be understood by those skilled in the art
that variations may be made thereto without departing from
the spirit of the invention or the scope of the appended
claims.