Abstract: An improved internal gear pump design is provided whereby the head plate includes a groove located vertically above the crescent for providing improved axial feed to the roots or innermost spaces between the idler teeth. The design of the pump also includes a stepped shaft design whereby the radius of the shaft immediately adjacent to the rotor is greater than an adjacent outboard section of the shaft. As a result, a chamber for housing the seal assembly is defined as the space between the stepped shaft portion, the annular seal plate, the outboard section of the shaft that has a lesser or reduced diameter, and the casing. The casing may also include a recess for providing sufficient space for the seal assembly. The larger section of the shaft is accommodated in a bushing mounted to the inside surface of the casing. The inside diameter of the bushing is large enough to accommodate the larger stepped portion of the shaft as well as the outside diameter of the seal assembly.

Abstract: An improved internal gear pump design is provided whereby the head plate includes a groove located vertically above the crescent for providing improved axial feed to the roots or innermost spaces between the idler teeth. The design of the pump also includes a stepped shaft design whereby the radius of the shaft immediately adjacent to the rotor is greater than an adjacent outboard section of the shaft. As a result, a chamber for housing the seal assembly is defined as the space between the stepped shaft portion, the annular seal plate, the outboard section of the shaft that has a lesser or reduced diameter, and the casing. The casing may also include a recess for providing sufficient space for the seal assembly. The larger section of the shaft is accommodated in a bushing mounted to the inside surface of the casing. The inside diameter of the bushing is large enough to accommodate the larger stepped portion of the shaft as well as the outside diameter of the seal assembly.

Abstract: An improved internal gear pump design is provided whereby the head plate includes a groove located vertically above the crescent for providing improved axial feed to the roots or innermost spaces between the idler teeth. The design of the pump also includes a stepped shaft design whereby the radius of the shaft immediately adjacent to the rotor is greater than an adjacent outboard section of the shaft. As a result, a chamber for housing the seal assembly is defined as the space between the stepped shaft portion, the annular seal plate, the outboard section of the shaft that has a lesser or reduced diameter, and the casing. The casing may also include a recess for providing sufficient space for the seal assembly. The larger section of the shaft is accommodated in a bushing mounted to the inside surface of the casing. The inside diameter of the bushing is large enough to accommodate the larger stepped portion of the shaft as well as the outside diameter of the seal assembly.

Abstract: A dual shaft, timed element high pressure industrial rotary lobe pump is provided. Lubricated sleeve bearings are located adjacent to the pumping elements. If the sleeve bearings are disposed on both opposing sides of the pumping elements, the lobe pump of the present invention can be operated at pressures as high as 400 psi. If sleeve bearings are disposed on one side of the pumping elements, the lobe pump can be operated at pressures up to 200 psi. Threaded thrust bearing cartridges enable fast and efficient positioning of the pumping elements during assembly without the use of shims. Recessed areas disposed in the head plate and in the casing bore provide improved loading and unloading of the pumping elements for high speed operation with reduced pressure pulsations and reduced noise. Access to the mechanical seals is simplified due to the easy removal of the timing gear box. The pump is also designed to accept standard mechanical seals as opposed to custom designed mechanical seals.