The field of this invention is pumping apparatus.
One common type of pump includes a pump housing which includes a stationary chamber portion for receiving fluid from a suction port and discharging fluid through a discharge port, the suction and discharge ports being connected to a fluid flowline network such as a pipeline. An external power source is provided by an electric motor or other power device mounted onto the outside of the housing. The external power source is attached to a drive shaft which extends through the pump housing to a position within the housing chamber. An impeller is mounted on the drive shaft for rotation with the drive shaft in response to activation of the external power source. Rotation of the impeller by the external motor and shaft combination causes the impeller to apply radial and/or axial fluid forces to a fluid passing through the housing chamber from suction to discharge.
Another type of pump features an "in-line" design wherein the impeller is connected directly to the rotor of an electric motor and the rotor is mounted for rotation about a stationary hollow shaft. The stator windings of the motor are mounted in a sealed housing that surrounds the rotor. Fluid enters at the suction, flows straight through the hollow shaft, to the impeller and through the entire rotor cavity to the discharge. A non-magnetic stator lining hermetically isolates the fluid from the motor windings, but allows their rotating magnetic field to turn the rotor and impeller. The fluid circulates through the entire rotor cavity to lubricate the bearings and cool the motor. A pump of this type is manufactured by the Crane Co., Chempump Division, Warrington, Pennsylvania.