Pump sealing system with throttle bushing

Abstract

A sealing arrangement is disclosed for a rotating shaft. A mechanical seal and a throttle bushing are mounted in a pump casing having a process fluid chamber and an end region. A shaft is rotatably mounted in the pump casing. The seal has a stationary portion mounted to the pump casing, and a rotatable portion mounted to the shaft. A throttle bushing surrounds the shaft and is connected to the casing. The throttle bushing has an inner surface that provides a fluid passageway between the inner surface of the throttle bushing and the shaft. The throttle bushing is spaced along the shaft at an axial distance from the mechanical seal, thus forming a barrier fluid space. The mechanical seal separates the barrier fluid space from the process fluid chamber. Barrier fluid migrates past the throttle busing inner surface, lubricates the pump bearings and gears, and is collected for reuse.

Dependencies are inferred from the claim text.