Fluid pumps with integral motors, such as so-called “canned” pumps, are generally employed in a variety of applications. For example, fluid motor pumps can be used to move fluids such as chemicals and oils. In operation, pressures generated by the pump head can act on the motor rotor in an uneven fashion. Such unbalanced forces tend to degrade motor performance and efficiency by increasing the amount of drag and resistance on the motor. Unbalanced forces acting on the motor rotor can also accelerate wear and tear and increase the development of leaks, which in turn increases maintenance requirements and costs.
What is needed, therefore, is a motor pump configuration in which forces act on the motor rotor in a more balanced fashion.