Patent ID: 7186093
Filing Date: 2007-03-06
Classification: F04D

Abstract:
1. A pump assembly for circulating a supercritical fluid comprising: a) an impeller for pumping supercritical process fluid between a pump inlet and a pump outlet; b) a rotatable pump shaft coupled to the impeller; c) a motor coupled to the rotatable pump shaft, wherein the pump assembly comprises a plurality of bearings coupled to the rotatable pump shaft; d) a plurality of flow passages coupled to the plurality of bearings; an injection means for delivering pressurized cooling fluid to the plurality of flow passages; e) a regulator, coupled to the injection means, for controlling the pressure of the pressurized cooling fluid; f) a coolant outlet for venting the pressurized cooling fluid from the pump assembly; g) means for measuring a first pressure coupled to the pump outlet; h) means for measuring a second pressure coupled to coolant outlet; and i) means for making a difference between the first pressure and the second pressure less than approximately 100 psi.