| dc.description.abstract | With increased oil and gas activity in low-temperature areas of the world, it is highly important that the industry utilize the most robust materials and zero-leakage solutions. The O ring is a type of elastomer sealer that, among other applications, is used in pipe connections. Such seals must withstand high pressures and sudden pressure drops, as well as different contact media and a wide temperature range.
The capability of the O ring has been investigated. Standard failure modes have been studied and the different features necessary to protect against leaks, such as oil and fuel resistance, resistance towards more aggressive fluids, operating temperature spectre and mechanical properties have been looked into.
The mechanical properties of filler/elastomer composites have been tested at a range of temperatures from room temperature to -25°C, with respect to Young s modulus and hysteresis (energy loss) development.
O rings for use in the arctic must have a sufficiently low glass transition temperature (Tg) for the environment in which the seals will be used. They should be impervious to contact media and gas diffusion, and they must be able to operate at high system pressures without suffering from compression set, extrusion or abrasion.
It has been found that Young s modulus increase significantly at temperatures below the Tg. When adding filler to the elastomer, a higher Young s modulus is obtained. This effect is bigger at low temperatures. When investigating hysteresis development, it has been found that as the temperature decrease towards Tg, the energy loss is much higher compared to ambient temperature. For cyclic testing, the energy loss is biggest from the first to the second cycle and even out from the second to the fourth cycle. | |
