Reaction plastic foam prodn. fitting - seals mixing chamber by O=ring and seal ring revolving with rotor shaft

摘要

A device to produce foam parisons from reacting plastics, i.e. isocyanates and polyols, includes a mixing chamber with a mixing rotor, two feed channels and an outlet nozzle. The rotor shaft is sealed by a sliding ring seal. This consists of a sealing ring which is coupled by dogs to the rotor shaft, and of an O-ring which seals both against the shaft periphery and against a bore of the sealing ring extension. The sliding ring provides an effective radial seal and the O-ring an effective axial seal. The rotor shaft suffers no wear because the ring seal revolves with it. The O-ring is also a good thermal insulator to prevent a rotor shaft temp rise from the hot ring seal.