Abstract: An oil filter can include porous material that acts to filter solid particulate matter from motor oil, that forms a chamber and that defines a central bore for receipt of a drive shaft of an electric motor forming part of a downhole device; and, disposed in at least a portion of the chamber, sorbent for removing aqueous liquids from the motor oil. A downhole device may be an electric submersible pump.

Abstract: A submersible pump stage comprises an impeller comprising a first front top disc and a first rear top disc, first blades located between the front and the rear top discs, a bushing and a diffuser comprising a second front top disc and a second rear top disc, second blades located between the second front and second rear top discs. The second rear top disc has through holes passing in end surfaces and located circumferentially. A number of the through holes is selected at least equal to a number of interblade channels. The holes are made so as to provide an overflow of a liquid from a front pocket of this stage of the submersible pump into each interblade channel of a preceding stage diffuser.