<p>A pump for evacuating heavy oil containing mechanical impurities and embedded in strata is disclosed. The pump includes one or more tanks (4), each with a flexible membrane (5), situated in an external pump casing. Each flexible membrane divides each tank into two compartments. The first compartment of each tank is in fluid communication with a collector cavity (25). The second compartment of each tank is in fluid communication with a suction cavity (29). The suction cavity includes a suction valve and a forcing valve. The pump also includes a hydraulic drive connected with the collection cavity so that operational fluid from the hydraulic drive is forced against the membrane upon insertion of a hydraulic rod (10) and creates suction against the membrane upon extraction of the rod. The external pump casing also includes a change lever (12) for connecting to external pipes.</p>
