Patent ID: 6220837
Filing Date: 2001-04-24
Classification: F04C

Abstract:
A progressing cavity pump comprising a stator having a bore therethrough formed with a female, two start, helical gear formation having a given pitch and lead, a cooperating rotor formed with a male, single start, helical gear formation having the same given pitch, an eccentricity and a minor diameter and a drive arrangement for causing said rotor to rotate and orbit relative to said stator, wherein the ratio of the eccentricity, e, of the gear formation of the rotor to its minor diameter, d, is in the range of between 1 to 4.6 and 1 to 5.2 and wherein the ratio of the eccentricity, e, of the gear formation of the rotor to stator lead, p.sub.s, is in the range of between 1 to 11 and 1 to 15.