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 sealing arrangement is disclosed for use in a pump. The sealing arrangement can include a first pump component having a first face surface. The first face surface can have a sealing protrusion thereon. A second pump component can have a second face surface positioned in confronting relation to the first face surface. The second pump component can define a sealing cavity for holding a fluid under pressure. The sealing protrusion is positioned to engage the second face surface when the first face surface is pressed against the second face surface so that the sealing protrusion seals against the second face surface to prevent movement of the fluid from the sealing cavity past the sealing protrusion. Other embodiments are described and claimed.

Abstract: A self-adjusting gear pump is disclosed. The pump may be a crescent internal gear pump, a gerotor pump, or an external gear pump. The pump includes a pump housing, gear housing, first and second gears, a side plate housing with a side plate, a shim and an end plate. The side plate moves between a first position contacting the first and second gears and gear housing, and a second position contacting the end plate. The side plate is spring biased toward the first position. A method is disclosed for match grinding the crescent plate (if used), gear housing and gears as a unit to provide a uniform surface. The side plate housing and side plate are similarly match ground. An assembly method is disclosed which allows the crescent plate to be moved with respect to the gear housing so that clearances between the crescent and the gear teeth are eliminated.

Abstract: A self-adjusting gear pump is disclosed. The pump may be a crescent internal gear pump, a gerotor pump, or an external gear pump. The pump includes a pump housing, gear housing, first and second gears, a side plate housing with a side plate, a shim and an end plate. The side plate moves between a first position contacting the first and second gears and gear housing, and a second position contacting the end plate. The side plate is spring biased toward the first position. A method is disclosed for match grinding the crescent plate (if used), gear housing and gears as a unit to provide a uniform surface. The side plate housing and side plate are similarly match ground. An assembly method is disclosed which allows the crescent plate to be moved with respect to the gear housing so that clearances between the crescent and the gear teeth are eliminated.