Patent ID: 8925197
Filing Date: 2015-01-06
Classification: F02C,F04D,F05D,Y10T

Abstract:
1. A method of inhibiting a thrust bearing capacity of a compression system from being exceeded during a surge event, said method comprising: biasing a thrust bearing with a biasing force acting in one of two opposite axial directions of a compressor shaft connected to the thrust bearing and to an impeller of at least one compressor having a back disk seal, the compressor shaft driven by a driver to drive the impeller through rotation of the compressor shaft, the compression system having at least one stage of compression provided by the at least one compressor; the thrust bearing having a first thrust bearing capacity and a second thrust bearing capacity to absorb axial loads acting upon the thrust bearing in the two opposite axial directions of the compressor shaft, respectively, the thrust bearing configured such that a first overload margin exists between the first thrust bearing capacity and a first surge force and a second overload margin exists between the second thrust bearing capacity and a second surge force, the first surge force and the second surge force acting in the two opposite axial directions and created during the surge event and the surge event produced by flow rate through the at least one compressor falling below a minimum flow required at a given speed of the impeller of the at least one compressor that is necessary to maintain stable operation of the at least one compressor; exerting the biasing force on the impeller and through the compressor shaft to the thrust bearing, during normal operation of the compression system, by producing a force difference between an impeller eye side force and a back disk force exerted on the impeller, opposite to the eye side force, by a high pressure outer annular region and a low pressure inner annular region separated by the back disk seal of the impeller; and the biasing force increasing one of the first overload margin and the second overload margin such that the other one of the first overload margin and the second overload margin that is not increased, is decreased and the first overload margin and the second overload margin are no less than about twenty-five percent of the first thrust bearing capacity and the second thrust bearing capacity, respectively.