Design and Manufacturing of an Accelerated Lifetime Tester for Non-Metallic Materials used for Compressor Valve Sealing Elements

摘要

It is quite difficult in actual field applications to properly assess the lifetime of non-metallic sealingelements for valves used in reciprocating compressors. This difficulty is due to the wide variety ofoperating conditions and contaminants these sealing elements encounter while in service. If one is todetermine which of these non-metallic materials will function optimally as sealing elements, a standardizedmethod for quantifying the lifetime of these materials must be developed. Further, due to the large numberof new non-metallic materials available, this standardized test method must be capable of reachingconclusions rapidly. Numerous design approaches were considered, including an existing design for thisapplication. It was determined, however, that a completely new approach should be employed for thisstandardized test method of producing controlled sealing element failure. Theoretical models weregenerated to assure the new device would produce appropriate impact velocities to generate failure in atimely manner. Upon analysis of these models, hardware designs were developed with the adaptation of alarge bore V8 engine at the center of this new machine design. The use of a V8 engine also has the addedbenefit of allowing for the examination of up to four test materials simultaneously. Special attention wasgiven to the minimization of the clearance volume for the test section and associated piping, as well as tothe temperature control of the system. The new machine was also analyzed theoretically to determine theeffects of varying the pressure, lift and RPM on overall lifetime of the test materials. After a thoroughanalysis had been performed, the system was manufactured. Testing of the new system showed that theincrease in capacity did not diminish its performance when compared to an existing device used for similarapplications. Additionally, this new lifetime tester was capable of a wider variety of operating conditionsthan the existing device, allowing for tailoring the machine for the material to be tested. This study focuseson the theoretical development, manufacturing and commissioning of a new concept for the lifetime testingof non-metallic sealing elements.