Pressurized seal for submersible pumps

Abstract

A submersible pump employs a sealed, oil-filled chamber with a moisture-sensing probe to detect the presence of any pumpage, such as water, which has leaked into the chamber. If contamination is detected, the pump may be shut down for repairs before it fails. Two mechanical seals are installed the lower seal is located between the pump and the oil chamber and an upper seal is located between the oil chamber and the motor. The improvement disclosed herein combines a pressurized oil accumulator with the pump oil chamber described above. The accumulator is divided into two compartments separated by a bladder, one compartment being connected to the reservoir of the pump and filled with oil for providing make-up oil to the reservoir and for accepting surplus (expansion) oil from the reservoir. The second compartment is pressurized and applies pressure to the bladder that, in turn, transfers the pressure to the oil in the first compartment and to the oil-filled chamber. The purpose is to pressurize the pump oil chamber in order to equalize pressure across the seals and thereby prevent failure of the seals or, at least, extend their life. The invention also includes apparatus for purging the motor casing with air and a pressure transducer for detecting a decrease in reservoir oil pressure.

Dependencies are inferred from the claim text.