Dynamic thrust balancing for centrifugal compressors

Abstract

Systems and methods for dynamically balancing axial loads in centrifugal compressors to reduce residual axial loads on the bearings used therein are described. A sensor or probe detects a parameter associated with the axial load acting on the bearing. Based on the detected parameter, the pressure in a balance chamber is controlled to adjust the compensating axial force generated by a balance drum.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This is a national stage application under 35 U.S.C. §371(c) of prior-filed, co-pending PCT patent application serial number PCT / EP2010 / 070001, filed on Dec. 16, 2010, which claims priority to Italian Patent Application Serial No. CO2009A000072, filed on Dec. 22, 2009, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]The present invention relates generally to centrifugal compressors and, more specifically, to balancing thrust in such compressors.[0003]A compressor is a machine which increases the pressure of a compressible fluid, e.g., a gas, through the use of mechanical energy. Compressors are used in a number of different applications, including operating as an initial stage of a gas turbine engine. Gas turbine engines, in turn, are themselves used in a large number of industrial processes, including power generation, natural gas liquification and other processes. Among the various type...

AI Technical Summary

Benefits of technology

The patent describes a system and method for reducing residual axial loads on bearings in centrifugal compressors. The system includes a sensor to measure a parameter associated with the axial load on the bearing, a control valve to adjust the pressure in a balance chamber, and a balance drum. The sensor detects a parameter, such as temperature or pressure, associated with the bearing. Based on this data, the control valve adjusts the pressure in the balance chamber to create a compensating force that reduces the residual axial loads on the bearings during operation. This results in a reduction of the damage caused to the bearings and increases the lifespan of the compressor.

Problems solved by technology

However, when the gas conditions change during operation in the compressor, the compensation provided by the balance piston may not be sufficient to avoid bearing overload.

Indeed some types of centrifugal compressors are more likely than others to experience such gas condition variations, e.g., in gas storage applications for multistage centrifugal compressors employing parallel operation, wherein the difference in axial thrust between the first and second sections of the compressor, linked to flow coefficient difference, may not be readily compensated for by the balance piston.

However AMBs also have the drawback that they are not capable of handling as much axial thrust as the conventional oil-lubricated bearings.

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