Patent ID: 9506468
Filing Date: 2016-11-29
CPC Classification: F01C,F04C,F05C

Claim Text:
1. A progressive cavity pump comprising: a cylindrical casing having a longitudinal axis, said casing being provided with an inlet opening at one end and with an outlet opening at its opposite end, a helical stator contained within said casing, said helical stator comprising a helical cylinder having a central axis coinciding with the longitudinal axis of said casing; a helical rotor suitable for rotating inside said helical cylinder so as to move a fluid from the inlet opening toward the outlet opening, wherein said helical stator further comprises at least one compensator arranged within said casing, between the casing and said helical cylinder, said helical cylinder and said compensator being adapted to deform in a direction perpendicular to said longitudinal axis, and wherein the helical rotor is adapted to rotate at a frequency of rotation, and wherein said at least one compensator decouples the natural frequencies of the helical rotor and helical stator assembly from the frequency of rotation of the helical rotor; said at least one compensator being defined by a coefficient of stiffness which satisfies the following relation: where: W is the frequency of rotation of the helical rotor, M is the total mass of the helical rotor and helical stator.