Abstract: A method of electroplating helical rotors provides uniform plating depth. A positive pole electrode having a bore with the same configuration as the rotor receives the rotor, which is the cathode. The bore is larger than the rotor, providing a uniform width clearance. Electrolyte solution is pumped through the clearance while electrical current flows to cause plating. The rotor is rotated and advanced during plating.

Abstract: A progressing cavity pump has features that allow it to be installed through tubing in a well. The pump has a stator and a helical rotor located in the stator. The rotor is rotated by a string of sucker rods that extends through the tubing to the surface. The tubing has a tubular seating member located at the lower end. A seating member is secured also to the lower end of the stator for reception in the seating member of the tubing. The seating members cooperate to prevent rotation of the stator and sealing. A rotor nipple extends above the stator and contains a drive rod which is connected between the sucker rod and the rotor. The rotor nipple has a restraining collar, and the drive rod has couplings located above and below the collar and spaced apart a selected distance to allow some vertical movement of the rotor with respect to the stator.

Abstract: A submersible device for pumping liquids and liquid slurries and for concurrently grinding and comminuting solid and semi-solid material contained in the liquid product to be pumped. The device is generally located in a reservoir containing the liquid product, the reservoir being, for example, a sewage collection tank in a positive pressure sewage system. The liquid product is initially shredded by a cutter bar and then drawn upwardly through a grinding and comminuting section where an abrasive drum mounted on a rotary drive shaft cooperates with an interior cylindrical stator surface to grind and comminute solids and semi-solids contained in the liquid product. From the grinding section, the resulting slurry is drawn into a centrifugal pump section with an impeller having a frusto-conical pumping face formed with symmetrical pumping cavities that are operable in both directions of rotation.