FIELD: oil and gas industry.;SUBSTANCE: sucker-rod pump with short plunger comprises a cylinder with suction valve and travelling valve and a short plunger equipped with a set of metal rings. In the set of metal rings with diameter D the rings are pressed to each other at butt ends and piled elastically to the sealed surfaces. At the short plunger case there are circular slots with placed elastic rings. At inner surface of the metal rings there are eccentric grooves at one side intended for elastic rings and to provide shift of the metal rings in radial direction to (0.1-0.3)D. In the set in each pair the metal rings in radial plane are unfolded towards each other in eccentric position per 180°. Each pair of the metal rings in radial plane is unfolded per 90° in regard to the each next pair. Length of the ring of metal rings is not less than two diameters of the plunger. The set of metal rings is pressed in longitudinal direction by a threaded bushing with a gap of (0.05-0.1)D in regard to the short plunger case.;EFFECT: invention allows improvement in the device reliability due to improved tightness of the short plunger sealing.;3 cl, 3 dwg
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