Improving torque performance in reciprocating compressors via asymmetric stoke characteristics

This chapter is intended to show that it is possible to obtain a considerable improvement in compressor performance and reliability by modifying the design of the compressor drive. Instead of the traditional slider-crank mechanism, which has been used as a drive since the compressor industry started, it is now possible to replace this drive by more sophisticated ones which offer more flexible stroke design. Such replacement has been made possible by the modern manufacturing methods and analysis tools which are currently at the disposal of industry and research bodies. Earlier work in the domain of proposing new linkages to drive positive displacement machines can be found in the work by Ooi and Wan (2000) who presented a proposal to drive the compressor piston directly from the back using a camlike mechanism. Also, Mimmi and Pennacchi (2001) proposed a pump drive that produces four variable-length strokes per crank revolution. On the other hand, Sultan and Kalim (2011) presented a five-bar geared linkage which can be used to drive a reciprocating compressor instead of the conventional slider-crank mechanism. The next section will present a mathematical model for the compressor operation