This thesis reports on the design and assessment of a high-pressure test device for the evaluation of rapid gas decompression (RGD) performance of elastomers. RGD damage is a common problem in elastomer seals used in industry applications. RGD results from when gas is diffused in elastomers at high pressures and then is rapidly released from the elastomer when the ambient pressure is lowered rapidly. The resulting damage includes deformation, swelling, blistering, cracking, and, ultimately, failure of the elastomer
To understand the effects of different gas depressurization rates on the elastomer, a commercial off-the-shelf high-pressure test vessel was obtained and modified. Additionally, components for introducing gas, releasing the gas at different rates, heating and temperature control, pressure sensing, data acquisition, and computer control were specified to create a complete test environment. A series of tests was conducted to evaluate the performance of the system based on the NORSOK M710 standard. Damage observed in the test samples is compared to other studies found in the literature. Qualitative correlations between observed damage and test parameters are also proposed. The test system was demonstrated at pressures to 10 ksi and temperatures to 250°F. The use of an actuated micrometering valve allowed depressurization linearly at 300 psi/min. However, the system as designed suffers from a 10% pressure loss during dwell time, does not provide linear depressurization rates below 250 psi/min, and requires a lengthy calibration procedure. Suggestions for addressing these shortcomings include re-machining the system to accept the factory-specified seal and designing a feedback system to control depressurization.Mechanical Engineerin
