A seal section for location between a submersible rotary pump and motor
has a primary mechanical seal and a secondary oil seal at the pump end of
the seal section. The mechanical seal has rigid seal faces that slide in
engagement with each other. The secondary seal has an inner portion that
seals against the shaft of the seal section and an outer portion that
seals against the housing. The seal section has a pressure equalizing
device for equalizing pressure of motor lubricant with well bore
pressure.