SCREW DOWNHOLE MOTOR Russian patent published in 2010 - IPC E21B4/02 

FIELD: engines and pumps.

SUBSTANCE: invention relates to oil-and-gas production, particularly to downhole motors (DHM) designed drill oil and gas wells. Proposed DHM comprises a section of working elements, i.e. stator and rotor arranged off-center inside the former, spindle section and internal joint assembly representing S-like bent torsion arranged below the rotor or inside it. Said torsion has working length L and diametre d set by the following ratios where ω=2π·Z·n, Z is the number of rotor teeth, E is elasticity factor, MPa; ρ is specific weight, kg/m³; G is axial force, "И"; n is frequency of revolution, s^-1; a, b are dimensionless parametres-coordinates set proceeding from internal part of torsion stability area limited by lines a=-3b+19, a=0, a=b; a=-b+4.

EFFECT: longer life and higher reliability.

2 cl, 3 dwg