US Patent 7540501 Segmented shaft seal

A segmented shaft seal is provided for circumferentially sealing an outer surface of a rotating shaft unit. The shaft seal includes a plurality of seal ring segments disposed within a housing having a circumferential spring holding the ring segments together. The ring segments further have lift grooves defined on the circumferential inner surfaces thereof to generate a radially outwardly directed lift force acting against the inwardly directed spring force. The lift grooves have a tapered profile radially and/or circumferentially to facilitate formation of the outwardly directed lift force as well as molding of the ring segments.