Abstract: A pump includes a front plate, a gear plate and a rear plate. A drive shaft has a drive gear, an arbor has a driven gear engaged with the drive gear, and first and second bearings are disposed in the gear plate. The first and second bearings receive the drive shaft and the arbor. The rear plate has drain ports adjacent ends of the drive shaft and the arbor. The arbor has an opening such that media that passes between the first bearing and an outer surface of the arbor is directed to the second drain port via the opening. A drain bushing is positioned against the front plate, and includes an opening for the drive shaft. The drain bushing has a chamber and a radial port. When pumped media passes between the first bearing and the drive shaft it is directed to the chamber and out the radial port.

Abstract: A gear pump includes a housing, at least one gear set and a plurality of end plates. The gear set may be positioned between the end plates so that side surfaces of the gears face corresponding side surfaces of the end plates. The side surfaces of the end plates may have a plurality of spiral grooves positioned directly adjacent the side surface of the gears. The plurality of spiral grooves may have a logarithmic shape. Thus arranged, when the gears rotate, fluid in the pump is forced along the lengths of the spiral grooves, creating a local high pressure region that forces fluid between the side surfaces of the gears and the end plates, minimizing or eliminating contact therebetween. In some embodiments the plurality of spiral grooves may be positioned on bearing surfaces of the pump instead of end plates.

Abstract: A gear pump includes a housing, at least one gear set and a plurality of end plates. The gear set may be positioned between the end plates so that side surfaces of the gears face corresponding side surfaces of the end plates. The side surfaces of the end plates may have a plurality of spiral grooves positioned directly adjacent the side surface of the gears. The plurality of spiral grooves may have a logarithmic shape. Thus arranged, when the gears rotate, fluid in the pump is forced along the lengths of the spiral grooves, creating a local high pressure region that forces fluid between the side surfaces of the gears and the end plates, minimizing or eliminating contact therebetween. In some embodiments the plurality of spiral grooves may be positioned on bearing surfaces of the pump instead of end plates.

Abstract: A pump includes a front plate, a gear plate and a rear plate. A drive shaft has a drive gear, an arbor has a driven gear engaged with the drive gear, and first and second bearings are disposed in the gear plate. The first and second bearings receive the drive shaft and the arbor. The rear plate has drain ports adjacent ends of the drive shaft and the arbor. The arbor has an opening such that media that passes between the first bearing and an outer surface of the arbor is directed to the second drain port via the opening. A drain bushing is positioned against the front plate, and includes an opening for the drive shaft. The drain bushing has a chamber and a radial port. When pumped media passes between the first bearing and the drive shaft it is directed to the chamber and out the radial port.