Patent ID: 7665975

Claim:
In a submersible pump assembly having a rotary pump driven by a motor, an improved seal section located between the motor and the pump for equalizing pressure of motor lubricant contained in the motor with well bore fluid pressure on the exterior of the pump assembly, comprising: a housing located between the pump and motor and having a pump end and a motor end; a shaft extending through the housing for causing the motor to drive the pump; a primary seal at the pump end of the housing, the primary seal having a rotary seal member mounted to the shaft for rotation therewith and in engagement with a stationary seal member stationarily mounted to the housing around the shaft; a non-rotatable secondary seal at the pump end of the housing on a motor end side of the primary seal, the secondary seal having an inner diameter portion in sliding and sealing engagement with the shaft and an outer diameter portion in stationary sealing engagement with the housing; and wherein the primary and secondary seals define a sealed chamber between them that is free of any inlet ports.