Centrifugal Compressors

OVERVIEWThe purpose of this unit is to provide trainees with an understanding of the general operation of centrifugal compressors and describe maintenance procedures commonly performed on them. The disassembly and re-assembly of a vertically split centrifugal compressor are explained.At the conclusion of this unit, trainees should have a basic understanding of how centrifugal compressors compress air. They should be able to identify the major components of a centrifugal compressor and describe precautions and preparations associated with centrifugal compressor overhauls. In addition, trainees should be able to describe the major steps in disassembling and reassembling vertically split centrifugal compressors and to describe some of the checks and measurements that are typically made. OBJECTIVESComponents and Operation--------------------------------------- * Identify characteristics common to all centrifugal compressors. * Identify the components of a horizontally split centrifugal compressor and a vertically split centrifugal compressor. * Describe the operation of a centrifugal compressor. Protective Systems and Practices---------------------------------------------- * Identify components of a typical centrifugal compressor lubrication system and describe its operation. * Describe surging. * Identify the components of a variable-pressure surge control system and describe its operation. * Identify the components of a constant-pressure surge control system and describe its operation. * Describe some common precautions and preparations associated with centrifugal compressor maintenance procedures. * Describe a procedure for cleaning or replacing an air filter on a centrifugal compressor. * Describe a procedure for cleaning or replacing an oil filter on a centrifugal compressor. Vertically Split Compressor Disassembly, Part 1 * Describe preliminary steps commonly taken before a vertically split centrifugal compressor is disassembled. * Describe one way to remove the intercoolers, diffusers, impellers, and diffuser covers from a vertically split centrifugal compressor. Vertically Split Compressor Disassembly, Part 2 * Describe a procedure for removing the pinion shaft assemblies from a vertically split centrifugal compressor. * Describe checks and measurements that can be made on the pinion shaft components after removal. * Describe how to package centrifugal compressor components for shipment. Vertically Split Compressor Reassembly * Describe a procedure for reassembling a vertically split centrifugal compressor. * Describe checks and measurements that can be made as a vertically split centrifugal compressor is reassembled. SUBJECTS * Components and Operation * Centrifugal Compressor Characteristics * Horizontally Split Compressor Components * Vertically Split Compressor Components * Centrifugal Compressor Operation * Protective Systems and Practices * Lubrication System Components * Lubrication System Operation * Surge Control * Variable-pressure surge control system components * Variable-pressure surge control system operation * Constant-pressure surge control system components * Constant-pressure surge control system operation * Blowoff recirculation * Compressor Maintenance * General considerations * Air filter maintenance * Oil filter maintenance * Vertically Split Compressor Disassembly - Part 1 * Preliminary Disassembly Procedures * Intercooler and Diffuser Removal * Impeller and Diffuser Cover Removal * Vertically Split Compressor Disassembly - Part 2 * Pinion Shaft Removal * Checks and Measurements * Packaging Components for Shipment * Vertically Split Compressor Re-assembly * Pinion Shaft Assembly Installation * Diffuser Cover and Impeller Installation * Diffuser and Intercooler Installation