The reliable sealing performance of MDC’s Del-Seal™ CF flanges is a result of a unique seal design and geometry which “captures” a metal gasket material. When a flat OFE copper gasket is pressed between the conical sealing edges of two Del-Seal™ CF flanges, a lateral cold flow of the gasket material occurs. This cold flow is limited by a vertical flange wall or capture groove that is concentric to the sealing knife edge. Further material flow away from the seal area is severely limited and high interface pressures are developed. These pressures cause gasket material to fill minor surface imperfections and produce a highly reliable seal. At high temperatures, the “capturing” geometry maintains high pressures despite softening of the gaskets. Del-Seal™ CF flanges can be baked to 450°C and cooled to -200°C and are suitable for vacuum service levels of 1x10-13 Torr. They are ideally suited for the rigorous demands of ultrahigh vacuum environments and capable of maintaining seal integrity through high temperature excursions. Del-Seal™ CF flanges are 100% compatible with the equivalent Varian Conflat® metal seal flanges.
