Oil-water interface control for submersible electric motor

Claim 1

Apparatus for maintaining a predetermined level of the oil-well fluid interface in a seal section associated with a submersible electric motor which drives a submersible pump comprising: a housing; means dividing said housing into a motor compartment and a pump compartment; an electric motor in said motor compartment, said motor compartment being filled with oil; a pump in said pump compartment, said pump compartment being filled with well fluid; a shaft means forming the driving connection between the motor and the pump and passing through the dividing means; means defining a chamber in communication with said motor compartment and said pump compartment and having both oil and water with an interface therebetween; means in said motor compartment for supplying oil under pressure to said chamber; means comprising a valve to regulate the supply of said oil to said chamber; sensing means comprising a float to sense the level of said interface and to control said regulating means to thereby sense changes in said interface level and regulate the supply of oil to said chamber in response to said changes in interface level; a cup-shaped member connected to said shaft means and defining an outer rotating wall of said chamber and a cylindrical portion of said driving means, and means defining an inner stationary wall of said chamber; and a cavity in said cylindrical portion communicating with said chamber, said float being confined in said cavity.