Progressive cavity pump

A method of making a progressive cavity pump the method comprising:

• providing a stator, wherein the stator includes a helical shaped interior with a first pitch;
• providing a rotor, wherein the rotor includes a helical shaped exterior with a second pitch, wherein the second pitch is different from the first pitch;
• placing at least one bearing on the rotor;
• and
• placing the rotor and bearing inside the stator;
• wherein
• the rotor is effective to rotate with respect to the stator and effective to move eccentrically within the stator to define at least one cavity inside the stator;
• and
• the bearing is sized and shaped so that the rotor is effective to rotate inside the bearing and the bearing is effective to move eccentrically along with the rotor.

A method of using a progressive cavity pump the method comprising:

• rotating a rotor inside, and with respect to, a stator to move the rotor eccentrically within the stator and to define at least one cavity inside the stator, wherein the stator includes a helical interior surface with a first pitch, and the rotor includes a helical exterior surface with a second pitch, wherein the second pitch is different from the first pitch,
• engaging an exterior surface of a bearing against the helical interior surface of the stator;
• engaging an interior surface of the bearing with the rotor;
• and
• eccentrically moving the bearing along with the rotor.