Reliability, Polymer, Plastic, Discharge
Polymers have been increasingly used in engineering parts along the last years. This trend can be explained by the several advantages of this type of materials as low weight, high damping, low friction, molding flexibility and the continuous development of novel grades presenting higher mechanical strength and thermal stability. These advantages are also important in the refrigeration field, mostly inside particularly in hermetic compressors. However, the thermo chemical environment inside these machines may be excessively harsh for most of the commercially available polymers. In this context, the development of reliable parts is very challenging but not impractical. Recently, a novel discharge system was developed using polymeric tubes made of Perfluoroalkoxy Alkane (PFA), which can help to improve the compressor efficiency through making feasible a better thermal management, reduced pressure drop and lower vibration transmission. Although PFA presents outstanding thermo chemical properties when compared to other polymers, its strength is just a fraction of what is found in steel tubes. This combination of characteristics may introduce other failure mechanisms to the discharge system, requiring new design criteria and approval process. The objective of this article is to explore these new design criteria and evaluations done in order to develop and approve the discharge tube used in a hermetic compressor.