Design And Testing Of A Zero-Net Radial Taper, Radially Compliant Face Seal

Abstract

Conventional seal designs, the net radial taper changes with operating conditions so that contact is not always maintained across their entire width and leakage can occur. The “zero-net” face seal combines two ideas to avoid this problem. The first is where the geometry of the cross section is selected so that thermal radial taper of both the primary and mating rings is essentially the same so that the faces remain parallel at various operating conditions. The second is where one of the rings is made axially very short so that it becomes radially self-aligning. The final result is a seal design where the faces remain in parallel contact across the face in spite of variable temperature, pressure, and speed. The concept has been proven in the laboratory. Wear profiles show that the seal readily contacts across the entire face width test data shows that the zero-net seal design has very low leakage in a water environment. The seal has been tested for more than a thousand hours and has been shown to give reliable and consistent performance. The zero-net face seal is expected to give longer, low-leakage life in field service than conventional rigid designs. The zero-net seal is now ready for field testing.