Progressing cavity pumps with split extension tubes

A pump assembly comprising:

• an inlet housing defining a chamber and a suction port communicating with the chamber;
• a extension tube in the form of a surface of revolution removably fastened to the inlet housing, the extension tube defining a longitudinal tube axis and a tube interior communicating with the chamber;
• a stator casing removably fastened to the extension tube;
• a resilient stator at least partially enclosed in the stator casing, the stator defining an internal passageway communicating with the tube interior, the internal passageway defining a helical inner surface, a stator axis, a stator length measured along the stator axis and an internal passageway cross-section normal to the stator axis;
• a rotor positioned in the internal passageway in abutment against the inner surface, the rotor defining a helical outer surface and a rotor cross-section;
• a drive shaft at least partially enclosed by the inlet housing;
• a first universal coupling connected to the drive shaft in the chamber;
• a connecting rod defining a first end positioned in the chamber and a second end positioned in the extension tube, the connecting rod being connected to the first universal coupling near the first end of the connecting rod in the chamber;
• a second universal coupling connected to the connecting rod near the second end of the connecting rod in the extension tube, the second universal coupling being connected to the rotor for actuating the rotor for eccentric movement along the inner surface of the internal passageway;
• and
• wherein the extension tube includes two sections separable along a dividing plane which includes the tube axis, each of the two sections being removably fastened to the inlet housing and the stator casing.

A pump assembly comprising:

• an inlet housing defining a chamber;
• a cylindrical extension tube defining a tube interior communicating with the chamber;
• a stator defining an internal passageway communicating with the tube interior, the internal passageway defining a helical inner surface, a stator length, a stator pitch less than the stator length and an internal passageway cross-section having a stator thread number;
• a rotor positioned in the internal passageway in abutment against the inner surface, the rotor defining a helical outer surface and a rotor cross-section;
• wherein the rotor defines a rotor pitch, the rotor cross-section defines a rotor thread number, the stator thread number is one greater than the rotor thread number and a ratio of the rotor pitch to the stator pitch equals a ratio of the rotor thread number to the stator thread number;
• a drive shaft at least partially enclosed by the inlet housing;
• a first universal coupling connected to the drive shaft in the chamber;
• a connecting rod connected to the first universal coupling in the chamber;
• and
• a second universal coupling connected to the connecting rod in the extension tube, the second universal coupling being connected to the rotor for actuating to rotor for eccentric movement along the inner surface of the internal passageway.