Abstract: The invention can be used in installations for extracting downhole fluid. The device is in the form of a protector which is arranged between an electric motor and a downhole pump and comprises at least one stage, which comprises a cylindrical body, a tube surrounding the drive shaft of the pump, nipples, a damping bushing, an annular piston in a chamber formed in the space between the body and the tube and dividing the chamber into two sections, which are filled with dielectric fluid and formation fluid, and a formation fluid and dielectric fluid divider which is mounted freely in the chamber at the end of the piston which is in contact with the formation fluid. The divider can move autonomously and is in the form of a single component consisting of two pipe lengths of annular elements which are arranged one in the other and are rigidly interconnected by means of a common base, which is mounted so as to adjoin the ends of the two lengths on the annular-piston side.

Abstract: The invention relates to crude oil production, and can be suitably used for hydroprotection of submersible electric centrifugal motors. A hydroprotection protector of a borehole pump electric motor comprises at least one stage, which stage includes a cylindrical body (7), a tube (8) coaxially positioned inside said body and surrounding a shaft (5), nipples (9, 10), a damping bushing (11), an end-face seal (12) and an annular piston (13), which piston is adapted to reciprocate in an annular chamber (14), which chamber is defined within the space between the cylindrical body (7) and the tube (8). The piston (13) separates the chamber (14) into two areas (15, 16) filled, respectively, with the dielectric fluid and the formation fluid arriving from the annulus.