Simone Pratesi

Advanced Design of Packing and Cylinders for Hyper-Compressors for LDPE Production

The optimization of packing cup geometry is important for improving the reliability of hyper-compressors. The complex arrangement and the transmission of loads through the various components requires the use of FEA to properly determine the stress level. The need to reduce the sensitivity to external factors requires an investigation with more advanced simulations. The entire cylinder and associated components such as head flanges, cylinder chambers and tie rods, were modeled. This provided the characteristics of the interfaces and the boundary conditions necessary to simulate the packing cups. Considering the thickness, ring housing profile, lube-oil holes, mating surfaces, interference-fit and diameter make it possible to obtain the stresses at the most critical points. This new simulation approach shows the effect of the parameters that influence the stress level at critical points, thus optimizing the packing cup profile and its relevant features.Copyright

Evaluation of Loads on a Hypercompressor Plunger in Service Conditions

The plunger is a very critical component for the operation of hyper-compressors. To achieve long packing ring life it is necessary to select very hard materials for the plunger. As a consequence of the special materials used, the plunger is very brittle. To guarantee safe operation it is necessary to have perfect alignment to avoid bending stress that could cause plunger failure. The effects of the whole system, including packing rings and supporting crossheads were analyzed using a multi-body dynamic simulation to determine the maximum loads acting on the plunger. This analysis verified the viability of this critical component during abnormal machine operating conditions.Copyright