PROCESS OF MANUFACTURE OF STATORS OF SCREW DOWNHOLE MOTORS Russian patent published in 2003 - IPC

FIELD: drilling technique. SUBSTANCE: invention refers to manufacture of screw downhole motors and rubber and metal articles for oil and gas industry. Proposed process includes electrochemical degreasing of frame, shot-blasting of surface, coating with adhesive, drying of adhesive film, preheating of mould, assembly of mould, pouring of rubber mixture, vulcanization, disassembly of mould, check of parameters of rubber encasing, test of specimen from rubber lot for fatigue. If fatigue endurance does not reach rated index of 100000 cycles and if positive values of fatigue strength at moment of rupture and relative elongation with rupture in narrow hardness range is between 72-78 Shore then vulcanization condition of specimens of given lot is altered in temperature interval 130-150 C and in time interval 20-60 min. On completion of vulcanization mould is cooled and after disassembly of mould stator is subjected to weathering to stabilize parameters of rubber ( encasing ). Introduction of flexible vulcanization conditions makes it feasible to manufacture stator which rubber encasing displays hardness of 72-78 Shore with required physical and mechanical properties ensuring long service life of downhole motors. EFFECT: long service life of downhole motors. 6 dwg, 3 tbl