SUBMERSIBLE POSITIVE DISPLACEMENT PUMP

The invention relates to pump equipment and can be used in the oil industry in the operation of marginal wells with difficult oil reservoir conditions. The pump comprises a submersible electric motor, a driven oil pump, a piston working pump consisting of a hollow upper guide rod, two pistons rigidly connected to a hollow central rod, inside which is disposed a hydraulic channel for interconnecting a compensating fluid below the pistons, said working pump also having suction and discharge valves and being rigidly connected via a rod to a hydraulic motor, the chambers of which are connected via an automatic reversing valve to a suction line and to a discharge line of the driven oil pump, wherein the latter has a safety valve mounted thereon which consists of a single piston with working channels disposed therein, said piston being rigidly connected to the hollow guide rod, a hydraulic compensator, the head-end chamber of which is connected to the outlet of the working pump, which passes via the central rod and the upper rod, and the chamber below the piston is connected to the head-end chamber of the working pump and via a channel in the central rod to the chamber below the piston in the working pump, an oil tank with fine oil filters, and a volumetric oil expansion compensator, wherein the electric motor is provided with a protector, via the shaft of which, the shaft of the electric motor is kinematically connected to the shaft of the driven oil pump. The invention provides for enhanced pump performance and manufacturability and also improves pump reliability and safety. L'invention concerne des équipements de pompe et peut s'utiliser en industrie d'extraction pétrolière dans le cadre de l'exploitation de puits de forage à faible débit présentant des caractéristiques problématiques du gisement de pétrole. La pompe comprend un moteur électrique immergé, une pompe à huile d'entraînement, une pompe de travail à piston constituée d'une tige creuse supérieure de direction, de deux pistons reliés rigidement par la tige creuse à l'intérieur de laquelle est disposé un conduit hydraulique pour faire communiquer le liquide de compensation sous le piston, y compris avec les soupapes d'injection et d'aspiration, qui est relié rigidement via la tige à un moteur hydraulique dont les cavités sont branchées en passant par une soupape d'inversion automatique aux conduites d'aspiration et d'injection de la pompe à huile d'entraînement; on a monté sur la dernière conduite un