Abstract: A rotating union for transferring a material stream, and especially a bearing damaging material stream, includes, a generally cylindrical body and an annular sleeve that is annularly spaced from the body and rotatably coupled thereto via a pair of axially-spaced bearings. The body and the sleeve are formed with ports and interconnecting passages for carrying the material stream and these ports and passages communicate with each other via a material transfer interface that is sealed by at least one dynamic seal assembly. Finely lapped material is used to improve the quality of the dynamic seal faces, and the seal faces are uniformly spring loaded. This, along with the axial spacing of the bearings, helps to minimize seal face misalignment and consequent leakage. In the event that material leakage does occur, the rotating union further includes a leakage collection area filled with a barrier fluid. The leakage collection area may encompass the bearings or it may be separate therefrom.