Application of On-Line Acceleration & Cylinder Pressure Measurements
Portable condition monitoring systems for reciprocating compressors have long provided cylinder pressure and other measurements on reciprocating compressors. By itself, cylinder pressure enables diagnostic tools such as pressure versus volume (PV) curves that allow the condition of the sealing elements inside the cylinder to be understood. It has also been understood that combining the cylinder pressure, rod load and crosshead acceleration curves allows one to assess the condition of the crosshead pin, piston rod to crosshead connection piston to piston rod and liner. On-line systems with similar measurement capabilities have gained commercial acceptancein recent years. These systems consist of a variety of transducers, electronic protection/data collection hardware and data analysis an trending software. Unlike portable systems, the transducers must be permanently attached to the compressor, the hardware installed at the compressor, often in hazardous areas, and the software integrated into the corporate IT structure. This paper presents a short tutorial on the economic justification, selection, design and installation of on-line condition monitoring systems for reciprocating compressors. A series of short case histories will be included to show the impact of correctly selected and installed condition monitoring systems on reciprocating compressor economics, operation and reliability.