New Developments In Centrifugal Compressors

Abstract

Design goals and operating experience with a new bearing design and a new microprocessor based compressor control system are discussed. Both of these developments are included in a compressor designed for the small centrifugal plant air market, but potential applications exist beyond this single type of turbo machine. The new bearing design is discussed in terms of its usage with two gear driven pinion shafts, one running at 36,000 rpm and the other running at 50,000 rpm. Major design aims achieved were for increased effective rotor/bearing system damping, rugged construction features and ease of assembly and maintenance. The microprocessor based compressor control system includes all normal monitoring functions plus adaptive digital control techniques with memory based learning. The dual loop interactive system is equipped only with setpoint adjustments, as the control is capable of self-adapting its PID values based on the last incremental system response.