Rotary gear transfer pump having pressure balancing lubrication, bearing

Abstract

An externally driven rotor is rotatable within a pumping chamber and is located in meshing relationship with an internal idler gear. An annular bearing mounted within the housing in confronting relationship with a peripheral surface of the rotor, provides a bearing surface and supports radially directed loads exerted by unbalanced fluid force on the rotor. A pressure balancing circuit is provided for transferring pressurized fluid from a discharge region in the pump to a backside of the rotor to at least partially balance axial forces exerted on the rotor by pressurized fluid. To provide bi-rotational capability, a cross-communicating passage and check valves are used for controlling the flow of fluid into the pressure balancing circuit. A vented seal chamber is also provided which includes passages and check valves communicating with ports which are arranged such that when the seal chamber exceeds inlet pressure, the check valve associated with the port acting as an inlet opens to discharge fluid from the seal chamber. A replaceable foot bracket is provided so that the mounting height of the pump can be selected to coincide with a mounting height of a drive motor to which it is connected eliminating the need for shims or other adjustments. An alternate rotor is disclosed including trimmed regions for reducing viscous friction when pumping high viscus fluids.