OIL-WELL SUCKER-ROD PUMP Russian patent published in 2003 - IPC

FIELD: oil producing industry. SUBSTANCE: pump is designed for lifting crude oil and other liquids from wells. Proposed pump contains plunger rod, cylinder with suction and delivery valves and plunger rod guide with through ports. Plunger is made in form of sections installed in tandem and sealed in cylinder by axially pressed sealing rings. Said sections are coupled with plunger rod and with each other for free displacement and deflection of section axis from plunger rod axis and other section axis by means of inner ring projection in hole on end face of plunger rod or other section engaging with upper external ring projection of other section connected to said section. Said projection is fitted with clearance in hole on plunger rod end face or end face of other section. Sealing rings are made with inner diameter calculated by formula Dir = Dp-Dor+Ds+2•h, where Dp is inner diameter of pump cylinder; Dor is outer diameter of sealing ring; Ds is diameter of cylindrical surface of section; h is summary thickness of layers of tolerable wear of rubbing surfaces of sealing ring and cylinder. Cavities are made on cylindrical surface of section at level of each sealing ring in which spring members are fixed to press off sealing ring corresponding to said level to one side of cylinder wall. Cavities of one level are located at opposite sides of cylindrical surface relative to cavities of neighbor level at displacement along axis of section through distance equal to height of sealing ring. Ring groove is made on upper external ring projection of section fitted in hole with inner ring projection in end face of plunger rod or section. Flexible cup is installed in ring groove to provide sealing of through channel of section and centering of its axis relative to axis of plunger rod or other section. End face surfaces of sealing rings and end face surfaces of section interacting with sealing rings and providing their axial pressing are flat ground and coated with antifriction material. When assembling pump plunger, sections of plunger are interconnected with turning of their cutting planes, on cylindrical surface of which cavities are located, through angle of 180/n degrees where n is number of sections. EFFECT: improved reliability, reduced expenses. 3 cl, 2 dwg