Abstract:
A connector for connecting electrical power to a well pump motor has cable and motor connector portions that mate with each other in a connected position. The connector portions have insulating members, each of which has a number of passages and an end face. Electrical contact members are mounted in each of the passages. The ones in the cable connector portion protrude past the end face of the insulating member. An end face seal surrounds each of the protruding contact members and is deformed by engagement of the end face of the motor insulating member when the cable and motor connector portions are in the connected position.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims priority to provisional patent application Ser. No. 60/844,051, filed Sep. 12, 2006. 

   FIELD OF THE INVENTION 
   This invention relates in general to downhole electrical connectors for use in electrical submersible pump applications, and in particular to a downhole pothead connector for use in oil wells. 
   BACKGROUND OF THE INVENTION 
   Electrical submersible pumps have been used in oil wells to pump well fluids for many years. These pumps are part of an assembly that includes a submersible motor. The pump assembly is typically suspended on tubing, and a power cable from the surface is strapped alongside the tubing. A motor lead is secured to the lower end of the power cable, the motor lead terminating in a connector that plugs into a receptacle of the motor. This connector is typically known as a pothead connector. 
   The motor is filled with a dielectric lubricant that is sealed from the exterior at the receptacle. The connector has seals that seal the electrical conductors from well fluid. A variety of connectors are known. In one type, the cable portion of the connector has a housing that contains two rigid insulating members separated by a deformable insulating member. Passages extend through the members for sealingly receiving the insulated electrical conductors. Electrical contact members or pins connect to the conductors and protrude past the forward insulating member. The remaining portion of the housing is filled with an epoxy. 
   The receptacle portion of the connector has a rigid insulating member with passages for receiving insulated conductors from the motor. Electrical contact members, typically sleeves, are located in the passages in the insulating member. When the cable portion of the connector is connected to the receptacle, the electrical contact pins slide into the electrical contact sleeves. 
   Even though this type of connector works well, in the motor lubricant becomes contaminated, debris from the oil can encroach into the connector and come into contact with the electrical contact members. The debris can cause electrical arcing in this region. 
   SUMMARY 
   The connector of this invention has end face elastomeric seals surrounding each of the electrical contact pins. Each end face seal has an inner diameter in sealing contact with the contact pin and a rearward side in abutment with the end face of the rigid cable insulating member. When connected, the end face of the motor insulating member contacts the end face seals and deforms them against the opposite end face. 
   Also, in the embodiment shown, a metal sleeve surrounds part of the protruding portion of each contact pin. The sleeve does not extend past the end face of the cable insulating member as far as the pins. A sleeve seals is fitted around each pin at the rim of the sleeve to prevent entry of debris between the sleeve and the pin. The electrical contact sleeves in the receptacle abut the sleeve seals to cause them to seal against the rims of the pin sleeves. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a longitudinal sectional view and depicts the interior of the pothead connector made according to an embodiment of the present invention, mounted to the terminal end of the flat downhole electric cable; 
       FIG. 2  is a side view of the pothead connector made according to an embodiment of the present invention entering a female assembly; 
       FIG. 3  is a sectional enlarged view of a portion of  FIG. 2 ; 
       FIG. 4  is a side sectional view showing the pothead connector fully inserted into the female assembly according to an embodiment of the present invention; and 
       FIG. 5  is a sectional enlarged view of a portion of  FIG. 4 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a longitudinal section view and depicts the interior of the pothead connector  10  made according to an embodiment of the present invention, mounted to the terminal end of a motor lead  12 . The upper or rearward end of motor lead  12  is joined to an electrical cable extending to the surface of the well. 
   Pothead connector  10  may have a wide variety of components. However, in this example, pothead connector  10  has a tubular housing  30  with a rearward end  32  through which cable  12  passes and a forward end  34  through which electrical conductor pins  18  extend. Pins  18  electrically connect to a female receptacle  14  of a down hole electrical submersible motor  15  ( FIG. 2 ). Tubular housing  30  preferably comprises two opposite end pieces, base  26  and cap  36 . Base  26  provides forward end  34 , and cap  36  provides rearward end  32 . 
   Referring to  FIG. 1 , cap  36  of tubular housing  30  has a tapered tubular end  38  which extends around the exterior of armor  40  of motor lead  12 . The interior of cap  36  is filled with epoxy  42 , which acts as a retaining means to secure conductor pins  18  within cap  36  in alignment for extending into base  26 . Epoxy  42  is a type of epoxy that is rated high for temperature service. The interior surface of the tapered tubular end  38  has a conical profile, with the rearward end periphery being smaller than the forward end periphery. After cap  36  is fastened to base  26  and epoxy  42  is cured, epoxy  42  will provide a conically shaped layer that is aligned within the conical profile of tapered tubular end  38  and prevents movement of cap  36  and base  26  inward over armor  40  of motor lead  12 . 
   As shown in  FIG. 1 , armor  40  has been stripped back from the terminal end of electrical power cable  12 , so that armor  40  has a terminal end enclosed within the tapered tubular end  38  of cap  36 . Preferably, each bare electrical conductor  22  is surrounded by one or more layers of conductor insulation  24  to protect and insulate the conductors from one another. 
   Insulation layers  24  will preferably extend within epoxy layer  42  so that the epoxy of layer  42  will bond directly to insulation layers  24 . The insulation layer  24  of each conductor  33  extends sealingly through a rearward rigid insulator member  52 , as shown in  FIG. 1 , and through a deformable elastomeric seal member  54 . In this example, seal member  54  is deformed between rearward insulation member  52  and a rigid forward insulation member  53 . Insulation layer  24  of each conductor  33  extends into forward insulation member  53  but not all the way through forward insulation member  53 . 
   At the outer end of base  26 , bare electrical connectors  22  provide a terminal end  20  of power cable  12 . Conductor pins  18  have bores which are separately mounted and then soldered over the terminal ends  20  of bare electrical connectors  22 . Conductor pins  18  are provided for mating with electrical connectors in receptacle  14  ( FIG. 2 ) of the submersible pump motor  15  ( FIG. 2 ). Insulation layer  24  of each conductor  22  extends up to and may abut conductor pin  18 , but does not extend over conductor pin  18 . 
   Still referring to  FIG. 1 , insulator members or blocks  52 , 53  are formed of a hard engineering grade plastic, such as polyetheretherketone (PEEK), and mounted at the forward or lower end of base  26 . Insulator blocks  52 , 53  are fixed within base  26  to prevent axial movement within the housing  30 . Insulator blocks  52 , 53  and seal member  54  are provided with a plurality of bores  69  (three in preferred embodiment) therethrough for electrical conductors  22  and for aligning them with the conductor pins  18 . Forward insulator block  53  has a flat forward end or face  55  that is in a plane perpendicular to conductor pins  18 . An elastomeric sealing boot  66  may extend around a forward lip of base  26  and provide a seal between tubular housing  30  and electrical submersible motor  15 . Boot  66  is shown in  FIG. 1  but not in the other figures. 
   At the interface between the forward end  55  of insulator  53  and each conductor pin  18  is an elastomeric O-ring end face seal  70 . Inside bore  69 , an optional sleeve  68  fits closely around each of conductor pins  18  and protrudes a short distance below forward face  55  of insulation block  53 . Sleeve  68 , if used, may be constructed to be part of conductor pins  18  and is formed of an electrically conductive metal. Each end face seal  70  encircles sleeve  68  of one of the conductor pins  18  and contacts end face  55  of insulator block  53 . The inner diameter of each end face seal  70  is substantially the same as the outer diameter of sleeve  68  for each conductor pin  18 . 
   In addition, an O-ring sleeve seal  72  may fit around each conductor pin  18  at the end or rim of each sleeve  68  to seal against any leakage between sleeve  68  and conductor pin  18 . The sealing engagement is formed by the inner diameter and the rearward portion of sleeve seal  72  contacting a shoulder on conductor pin  18  and contacting the rim of sleeve  68 . The outer diameter of sleeve seal  72  does not form a seal and shown as being only slightly greater in diameter than sleeve  68 . 
   Referring to  FIG. 3 , female receptacle  14  will now be described. A receptacle block  74  of a rigid insulation material is mounted in female receptacle  14 . Receptacle block  74  has a plurality of holes  76  (one shown), one for each conductor pin  18 . A mating electrical conductor sleeve  75  (shown only in  FIG. 3 ) is located within each hole  76  in receptacle block  74  to accept one of the conductor pins  18  as pothead  10  is connected to female receptacle  14 . Each conductor sleeve  75  is connected to one of the wires within motor  15 . Receptacle block  74  has a cylindrical portion with a diameter slightly smaller than the inner diameter of base  26  at its forward end for sliding into lip  26 . Receptacle insulating member  74  has an end face  78  that is flat and parallel with end face  55  of insulating member  53 . 
   Referring to  FIGS. 3 ,  4 , and  5 , during operation, end face seals  70 , which are between face  55  of insulation member  53  and face  78  of receptacle member  74 , are contacted and deformed by faces  55 ,  78 , thereby creating an effective barrier that prevents debris from getting into the area between conductor pin  18  and pothead  10 . The axial compression on each end face seal  70  causes its inner diameter to seal tightly around sleeve  68 . However, the outer diameter of end face seal  70  does not form a seal. When fully connected, as shown in  FIG. 5 , a small clearance exists between end faces  55 ,  78 . 
   When connected, sleeve seal  72  enters receptacle  76  but is not deformed by receptacle  76  because its outer diameter is smaller than the inner diameter of receptacle  76 . If electrical contact sleeve  75  is sized appropriately, sleeve seal  72  may make contact with the end of electrical contact sleeve  75  to deform sleeve seal  72  against the rim of sleeve  68 . The inner diameter of seal  72  forms a seal around conductor pin  18  and the rim of sleeve  68  to reduce entry of material between sleeve  68  and conductor pin  18 . 
   The invention has significant advantages. The end face seals provide an additional barrier to the entry of contaminated material into the area of the electrical contacts. The sleeve seals, if employed, provide still another barrier. 
   It is to be understood that the invention is not limited to the exact details of the construction, operation, exact materials or embodiment shown and described, as obvious modifications and equivalents will be apparent to one skilled in the art. For example, the pins could be located in the receptacle and the conductor sleeves could be located in the cable end housing.