Abstract: A system and method for transporting high-viscosity, high-solids, dewatered materials essentially includes a progressing cavity pump system utilizing a twin-screw feeder with an extended tunnel section. The feeding of the material into an extended tunnel section of the twin screw feeder creates a positive pressure, which assists in feeding the product into the suction housing of the progressing cavity pump, and correspondingly, into the pumping elements. This increases volumetric (fill) efficiency of the progressing cavity pump, thereby allowing a smaller pump to be used. The suction housing of the progressing cavity pump includes an auger positioned therein that is directly coupled to, and preferably integral with, the progressing cavity rotor. The universal joint is moved from the position in front of the stator entrance to a point behind the auger and suction inlet opening to improve flow of material from the suction housing to the progressing cavity pump elements.

Abstract: At least two progressing cavity pumps or pump sections are connected in series. The flow volume rate of the second pump or pump section is less than the flow volume rate of the first pump or pump section. If there are more than two pumps or pumps sections, the flow volume rate of the third pump or pump section would be less than the flow volume rate of the second pump or pump section, and so on. The cascade arrangement of progressing cavity pumps can be achieved by interconnecting separate pump assemblies end to end. The cascade arrangement of progressing cavity pump sections can be achieved by the attachment of the rotor/stator pairs of each pump section in series with suitable universal mechanisms and housings. Such a cascade arrangement of progressing cavity pumps or pump sections allows and compensates for the compressibility of the gas in the two-phase or multi-phase fluid being pumped, especially in pumping operations requiring high differential pressures.

Abstract: A progressing cavity pump is provided in which the compressive fit between the rotor and stator is gradually reduced with the distance from the suction end of the pump. This gradual decrease in compressive fit allows for increased slippage near the discharge end of the pump, resulting in better distribution of the internal differential pressure along the length of the pump. The differential pressure distribution in turn reduces heat build-up near the discharge end, increasing the life of the elastomeric stator or rotor.

Abstract: A progressing cavity pump comprises an inlet housing defining a chamber, an extension tube defining a tube interior communicating with the chamber, a stator defining an internal passageway communicating with the tube interior, a rotor positioned in the internal passageway in abutment against an inner surface of the internal passageway and a coupling at least partially enclosed by the extension tube. The coupling is connected to the rotor for actuating the rotor for rolling movement along the inner surface of the internal passageway of the stator. In an especially preferred form, the extension tube is in the form of a surface of revolution and is separable into first and second sections along a dividing plane which passes through the center of the tube. Fasteners are used to removably fasten the first and second sections to each other, the housing and the stator casing to provide access for inspection of the coupling, the rotor and the stator.

Abstract: A seal for a gear ball joint in a progressing cavity pump. The seal includes a flexible seal member having a depending flange portion including five sealing surfaces for sealing against mating parts of the joint assembly. The seal also includes an annular stiffening wire molded within the flange portion to provide dimensional stability during seal molding, structural support during assembly and increased working life.