Abstract: A sealing ring assembly for use in a pulp refiner unit which includes a housing having a pair of counter-rotating discs and a stock feed inlet mounted to the housing adjacent an opening provided therein for directing raw material toward the discs includes a seal ring defined by a circular flange section detachably mounted on the stock feed inlet within the housing opening and a projecting ring section extending from the flange section toward the discs. The sealing ring assembly also includes an inlet ring defined by a flange section detachably mounted on the disc most adjacent the housing opening and a projecting ring section extending from the flange section toward the housing opening for concentrically receiving the seal ring's projecting ring section thereby defining an annular clearance region between the projecting ring sections.