ANALYSIS OF SET OF VALVE FROM HERMETIC RECIPROCATING COMPRESSORS UNDER ACCELERATED LIFE TEST (ALT) BY ALTERNATIVE MACHINE IN REPLACEMENT OF THE USUAL COMPRESSOR BENCH TEST

摘要

In search of plenty understanding and continuous improvements of hermetic reciprocating compressors several analysis methods have been applied. Among them finite element methods (2D and 3D) and laboratorial experiments are the most common and useful to validate the compressor design, some of them particularly applied to the valve design; which is of such importance to the compressor effectiveness. An alternative endurance test machine in replacement to the reciprocating compressor is presented to test a set of valve plus the valve plate under accelerated life test (ALT). Only one particular set of valve model (valve plus valve plate) was tested; which undergo several speeds/loads at the same pressure level under controlled humidity. The results obtained from the valve set were plotted on a graph that reveals the endurance versus the machine speed/load change, those curves represent the valve Weibull ALT lifetime. The values were analyzed using the normality and the probability approaches beyond of t-student to determine the difference among the lifetime values towards the p-value. Beyond of the Weibull graph, microscopic analysis of fractured surface of the valve and on the valve plate seat using SEM/EDS was done to have a better phenomena characterization based on the damage and fracture micromechanics. Based on the Weibull curve and microscopy analysis gotten the flapper valve set, the performance of this assembling is known. Those results confirm the machine reliability and give the valve endurance lifetime under impact test.