Downtime Reduction on Reciprocating Compressors with Heat-Free Hub Design
Reciprocating compressors are a notoriously high stress application, especially when being driven by a diesel engine. The torque pulsations are enormous, and the torsional vibrations can be fatal to equipment. Therefore, the shafts in these compressors are very large to compensate for the high stresses. Some manufacturers have realized that one method for reducing stress is to eliminate the keyway. Without the keyway cut into the shaft, there are no stress risers that can lead to cracks. Another advantage of not using a keyway is the ability to make the shaft diameter smaller while maintaining the same stress level. Keyway or no keyway, the coupling hub still needs to carry high torques with a large service factor (at least 3) without slipping or breaking the shaft. In the case of keyless shafts, the shrink fit is usually tighter than in the keyed case.